ISSN 0385-2520

Rock Magnetism

and

Paleogeophysics

Volume 16Decemher 1989

DELP Publication No. 29 ([)

Edited by Rock Magnetism and Paleogeophysics Research Group in Japan

Published by the Japanese National Committee for theDynamics and Evolution of the Lithosphere Project (DELP)

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II

PREFACE

This volume is the annual progress report of the Rock Magnetism and PaleogeophysicsResearch Group in Japan for the year 1989. We have published annual reports with a titleAnnual Progress Report of the Rock Magnetism (Paleogeophysics) Research Groups in Japan in1963, 1964, 1965, and 1967. Since 1973, the title changed to Rock Magnetism and Paleogeo­physics and the reports were published annually (except 1976).

As the previous reports were so, this volume contains a collection of summaries, extendedabstracts or brief notes of the research works carried out in our group this year. Many of thereports contain materials which may undergo a significant change or may be revised as theresearch activity continues. In this respect, readers are warned to regard them as tentative, andare also requested to refer from a complete paper if such is published as a final result. (Namesof journals appear at the end of individual articles if they are in press, submitted, or in prepara­tion for submission to some scientific journals).

This is the last year of the DELP Program and also the last year for me to serve as the edi­tor of this annual report. When I began in 1973, I did not think that I will be continuing to doso for more than five years. However, the volumes served as good media to inform the foreigncolleagues what we are up to in Japan. We have had large number of quotations from outsideJapan. At present, there are divided opinions in our group regarding the future of the annualreport. As many of the works nowadays are published in international journals without muchdelay, some think that we do not need such media any more. On the other hand, there are alsoopinions that the information channel cultivated in the last 16 years became too valuable toabandon so lightly. The future, therefore, depends on the decision of our group to be madewithin 1990, and also on the responses received from the colleagues overseas who are receivingthem. I would like to take this opportunity to thank the authors for contributing the abstracts forthe past volumes, and to the readers in general who encouraged us for this publication. As atoken of thanks from the outgoing editor to the authors and readers of Rock Magnetism andPaleogeophysics, I have prepared a permuted index for Volumes 1 to 16 inclusive.

This volume is published with a financial aid from Ministry of Education, Science and Cul­ture for the Dynamics and Evolution of the Lithosphere Project (DELP). It is Publication No. 29of the Japanese DELP Program.

TokyoDecember 1989

Masaru KonoEditor

Rock Magnetism and Pa1eogeophysicsResearch Group in Japan

iii

Rock Magnetism and Paleogeophysics, Volume 16

Table of Contents

it ;t 'hi ~ ii

Preface iii

Table of Contents iv

MAGNETIC FIELD, ANOMALIES, ITS GENERATION

S. Sakai, H. Oda, T. Nakayama, and H. Doi 1Abrupt Jump in the Magnetic Total Force at the Blast by Gun Powder ­Interpretation by Remanent Magnetization

T. Fujiwara, S. Ogura, H. Kinoshita, and R. Morijiri 4Study of Crustal Structure in the South Boso Peninsula Inferred from Mag-netic Anomalies

M. Kono 8Computer Algebra for Automatically Solving Kinematic Dynamo Problems

ROCK MAGNETISM, MEASURING INSTRUMENTS

H. Ueno 16Opaque Minerals in Hydrothermal Alteration Zones and Their Relevance toRock Magnetism

M. Torii, H. Oda, and H. Shibuya 20Thermal Variation on Initial Susceptibility by Using Automatic High­Temperature Susceptibility Meter

M. Kono, M. Hoshi, K. Yamaguchi, and Y. Nishi 24An Automatic Spinner Magnetometer with Thermal Demagnetization Equip-ment

ARCHEOMAGNETISM, PALEOINTENSITY

T. Nishitani and C. Shimamura 30Archeomagnetic Investigation of Ohdateno Remain in Akita Prefecture

IV

H. Morinaga, 1. Horie, H. Maruyama, and Y. Yaskawa 33A Geomagnetic Excursion Recorded in a Stalagmite (Speleothems) Collectedfrom West Akiyoshi Plateau, Japan

C. Itota, H. Morinaga, M. Kusakabe, F. Murata, S. Yamaguchi, N. Isezaki, H. Goto,and K. Yaskawa 38

Paleoenvironmental Secular Change in Ch'i-Lin-Ts '0, Tibet as Inferred fromPaleomagnetism and Stable Isotope Analysis

H. Sakai 42Paleointensity at the 75,000 Years B.P.

PALEOMAGNETISM, TECTONICS

M. Miki and Y. Otofuji 44Paleomagnetic Study on Miyako-Jima Island in the South Ryukyu Arc

M. Miki, S. Kondo, and Y. Otofuji 47Paleomagnetic Study on the Central Ryuku Arc - Kinematic History of theRyukyu Arc-

Y. Otofuji, T. Itaya, and T. Matsuda 49Fast Drifting of Southwest Japan Inferred from Paleomagnetism and K-ArDating

H. Oda, M. Torii, and A. Hayashida 51Paleomagnetic Study and Fission-Track Dating in Yanagawa and TakadateArea, Northeast Japan

Y. Adachi, H. Morinaga, Y.Y. Liu, G.Z. Fang, and K. Yaskawa 57Preliminary Results from Paleomagnetism on Apparent Polar Wander Pathfor the South China Block

M. Funaki, M. Yoshida, and P.W. Vitanage 61Natural Remanent Magnetization of Some Rocks from Southern Sri Lanka

Permuted Index for Volumes 1-16 67

v

1990. 3. 28

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ABRUPT JUMP IN TBE MAGNETIC TOTAL FORCE AT THE BLAST BY GUNPOWDER -INTERPRETATION BY REMANENT MAGNETIZATION

Hideo SAKA~l, Hiroyuki ODA1 , Takesi NAKAYAMA2 andHikaru DOl

1 Department of Earth Sciences, Faculty of Science,Toyama University, Gofuku 3190, Toyama, 930, Japan

2 Kamitakara Geophysical Observatory, DisasterPrevention Research Institute, Kyoto University,Kamitakara, Gifu, 506-13, Japan

Piezo remanent magnetization (PRM) may exist commonly at thestress concentrated region. Nagata and Kin~~hita_f1965) showedwhen the piezo remanence of the order of lObar is induced inthe sequence underground, the magnetic total force at the surfacemay change in the magnitude of 1 to 10 nT. When the shock isimposed to the rocks in a quite short period, the remanentmagnetization similar to PRM may be acquired. Nagata (1971)named it as the SRM (shock remanent magnetization).

In 1986, October 22, the cooperative research with theartificial earthquake was made at the Ohtaki village in NaganoPrefecture (Figure 1). The main purpose of the project (Thejoint group of seismological research in western NaganoPrefecture, 1988) was to investigate the crustal structure aroundthis area in detail. At this project, we made the observatoryexperiments of the magnetic total force in order to identify whatkind of change in the magnetic force will be induced by theartificial earthquake. The results may be useful for thediscussion of the stress-induced magnetization.

NPROTON N

IIt~:,AST

13311

GOH

G.P .8GKG

//~CASTI35'50'

A "@'PROTON

// 0 10 20 30M tI

131'40'

Fig. 1. Map of the area where theartificiai earthquake experimentwas made. The star mark shows theblast point.

Fig. 2. Map around the blast point(star mark). Double circle representsthe position of the proton sensor.

The artificial earthquake was produced by the blast of 86 Kggun powder placed at the depth of 68 m below ground (point A ofFigure 2). The magnetic total force was measured by a protonprecession magnetometer (Barringer model GM 122) which wasmodified to record the data on the printer. We set it 33 m from

1

the blast point. The sensor of the magnetometer was positionedon the aluminum pole of 2 m in height. We supported the aluminumpole f~rmly so as to restrain the movement of the sensor at theblast. The magnetic total force was measured from twenty minutesbefore the blast time until three hours after. The data weresampled at 6 second intervals. The apparatus was run withbattery power.

Figure 3 shows t,he change of the magnetic total force aroundthe blast time. The jump of the magnetic force up to 3 nT wasobserved at the blast. The general trend in the fluctuation ofmagnetic force before and after the blast was concordant withthat of the Amo stationary observatory 50 Km north-westward fromOhtaki district. The proton sensor was fixed rigorously and themagnetic gradient was less than 1 nT within a 15 cm radius fromthe sensor. Therefore, we could not consider that the movementof the sensor at the blast have caused the observed change in themagnetic force. We concluded that the jump of the magnetic forcewas induced by the change of magnetic properties underground atthe blast.

TOTAL FORCE

AMO

47092

. 47097• nT

f ..··········3nT

.' '\.~~~ __.- J ~ -._..__ .-46670

OHTAK I

46675nT

40

19S6. 10.22

20 30 min

I(BLAST)

10 12 15

TIME

55

46065 0h lh'--.---~-..,.....-....,--+--~-~.----,..--~-~-~,-l-47087

o

Fig. 3. Variation of the total magnetic force observed around theblasl time (1:12 am), Dolted line shows the data recorded at Amostatlon.

The increment in the magnetic force at the blast did notdecrease during the period of 30 minutes after the shot time<Figure 3). According to the succeeding observation, theincrement did not decrease after 1 hour from the blast time.

One of the possible cause for this irreversible change inthe magnetic force is the effect of iron casing around the blastpoint. The iron casing of the diameter of 120 mm was placed atthe depth from 1.2 to 400 m in order to set the gun powder.Figure 4 shows the contours map of the magnetic force around theblast point observed 1 month after the blast time. It suggeststhat the iron casing has the effective role for the distributionof the magnetic force around the blast point. At the blast, thecasing may have been deformed and/or heated to the hightemperatures and the susceptibility <p) of the iron casing mayhave changed. This change may have distorted the distribution ofthe magnetic force and caused the observed increase of the

2

magnetic force.

TOTAL FORCE CONTOURS MAP

f~467000T. .

'e­PROTON

o 20M

Fig. 4. Contours map of themagnetic force around the bl~st

point observed at the time1 month after the blast.

N+ + + .. + + + + +

40500

1+ + +

,

+ +

+ + + + +

+4G1OO

+ + + +

+ + + + +

+ + + +

+ + + + + + + + +

+ + + + + + + + + nT

Fig. 6 Calculated distribution of thetotal magnetic force when the Ironcasing was placed vertically at theblast point. We assumed the casing<p=200) of the diameter 120 mm wasset at the depth from 1.3 to 400m.

Figure 5 shows the calculated distribution of the magneticforce when the iron casing (p=200) is placed at the blast point.The distribution of the magnetic force shows the minimum at thenorth of blast point and maximum at the south. The observeddistribution in Figure 4 deflected from the north-south trend inthe calculated distribution. It indicates that the magnetizationunderground around this region also contribute to thedistribution of magentic force. The sequence around the blastregion consists of andesites and sedimentary rocks. NRMs of thedrilled core (sedimentary rocks) at the blast point weremeasured. They showed the reversed polarity with the intensityof 10- J mA 2 / kg. When the reversed NRM was decreased or brokenaccording to the acqusition of PRM and/or SRM at the blast, themagnetic force at the surface may increase. That is, the inducedNRM change in the underground sequence is also resposible for theobserved irreversible change in the magnetic force. The furtherstudy of the magnetoelectric effect at the artificial earthquakeis necessary to know the detrails.

REFERENCES

Nagata, T. 0971> Pure Appl. Geophys., 89, 159.Nagata, T. and H. Kinoshita (1965) J. Geomag. Geoelectr., 17,

121.The Joint group of seismological research in western Nagano

Prefecture (1988) The 1986 Joint Seismological Research inwestern Nagano Prefecture -Technical report-, 340.

3

STUDY OF CRUSTAL STRUCTURE IN THE SOUTH BOSO PENINSULAINFERRED FROM MAGNETIC ANOMALIES

1Toshiya FUjIWARA, Sumio

and Rie

1OGURA , Hajimu

2MORIjIRI

1KINOSHITA

1.Chiba University, Yayoi-cho, Chiba 2602.Geological Survey of japan, Tsukuba, Ibaraki 305

We have been conducting land magnetic survey using protonpreccession magnetometer in the south Boso Peninsula from 1985 to1989. In addition to these data, one track magnetic data wasacquired in the Tokyo Bay east side of Boso Peninsula by DELP1987 cruise (Isezaki et al. ,1989). So we could construct a de­tai led magnetic anomaly map in this area (Fig.l, Fig.2).

Data is reduced by IGRF 1985 model referring Kano-zan Geo­detic Station, Geographical Institute (about 20km north of surveyed area) to subtract Sq variations. Reduced data is refined byapplying upward continuation tecnique to a level of 1500ft(about460m). H in Fig.3 mark means relative high anomaly and L mark islow anomaly.

Magnetic basement map (Fig.5) is obtained by a two-layermodel inversion using pseudo-gravity and reduction to the pole(Okuma et al. ,1989) (Fig.4). Magnetization is assumed to beuniform with magnetization intensity of 2 Aim and parallel to theambient geomagnetic field vector.

Map of Fig.5 is probably explained by steeply decline base­ment from south to north and vertically magnetized bodies. Fig.5shows that basement curves down to 2km deep and its horizodnitalN-S spread is about 5km. The basement seems to be shallower inthe northern part of surveyed area. This matter as mentionedabove is maybe more understandable rather fig.4 map than fig.5map because Fig.5's calculation mesh is still rough. Fig.5's mapis obtained basically by downward continuation of fig.4. Locationof steep change of basement give a dense contour lines. Lowmagnetic anomalies is caused by declining of basement and highmagnetic anomaly reveals by vertically magnetized bodies.

Location of vertically magnetized bodies match to area ofoutcrop of Mineoka Ophiolites belt. (They are marked by opentriangle in Fig.l) Tectonic setting of the Mineoka Ophioliteshave been studied by several authors. Ogawa and Taniguchi (1987)discussed emplacement process of these rocks associated with theobduction of plate. Previous study of simulation which explainsgravity and magnetic anomaly in this area is given in a form of aslab dipping toward south by Tonouchi (1981). Our present resultdoes not seem to support this idea positively.

4

Fig.l Schematic map of surveyed area.

....

.'

.'... .'.

.'. ' .

, .~~.: :~.::/ ;~:..... :. :~..::...' :(;4'.:: r".:::.-:.:..:........) ... '.''.. .... .. '. ", :~.. '. • ." •••••••• _ •• 1 : "';'''

.' •••••: ,...... I. 'I' I.: I. • ." : 1.1 .'_: • II' • :.. . - ....• i ...., ." I, ••• I, •.... I. . ... I. .!, . '. ",.!., :,. •.L..... '. .

:...:':~':'- ..::} :.~f··,,~./· :,,:;,"~-:'(."\' :::'.....~....::; •• , .,.,..... II • ·.U· '"

:=:.' .....,:.' :. /..}..~:;.' ./.f} . .. ~~ II • :. II .': I ••. .. .

· ..1: ., . .:.....:.,'.. '." .1:•. I.::.:. '. ..II.. ... . ..

. . . II .. I:. .~. _'," .1 ..: ..

. , :.'

Fig.2 Surveyed area with data points.

5

.0

35<OO'N

Ok m

-100.0 -100.0 -100.0

Fig.3 Magnetic anomaly map, contour interval is 20 nT.

100.0

.0

I 0.0

1 0.0

1 0.0

10 .0200.0

00.0

100.

100.0

100.0

100.0

100.0

100.0

100.0

200.0

100.0

100.0

100.0

100\0 0 k m 200.0200.0 ~o

V«?rio/J/Z2IUO.O

0.0

0.0

0.0

0.0

0.0

-100.0

100.0100.0

100.0

0.0

Fig.4 Pseudo-gravity map, contour interval is 20*10"6 nT*m.magnetic anomaly transform to pseudo-gravity anomaly, top

magnetized body correspond to point of anomaly's peak.

Whenof

6

III >.5.5'" 1

13 1 "'1 5

111.5,...2

Em 2'""2.5

[] 2.5'" 3

~ <3

Fig.5 Magnetic basement map inferred from Fig.4, unitbelow surface in km,

References

is depth

Isezaki et al. (1989) Bull. Earthquake Res. Inst., Univ. Tokyo.,64, 179-222

Kinoshita,H et al. (1987) Rock Magnetism and Paleogeophysics.,14, 97

Ogawa,Y and H.Taniguchi (1987) Science Reports Department ofGeology Kyushu Univ. (in Japanese with English abst.), 15,1~23

Okuma,S et al. (1989) Butsuri-tansa.(in Japanese with Englishabst.), 42, 82-96

Tonouchi,S (1981) Ph.D Thesis, Univ Tokyo.

7

COMPUTER ALGEGRA FOR AUTOMATICALLY SOLVINGKINEMATIC DYNAMO PROBLEMS

Masaru KONODepartment of Applied Physics, Tokyo Institute of Technology

Ookayama 2-12-1, Meguro-ku, Tokyo 152, Japan

1. Introduction

Since the classical paper of Bullard and Gellman (1954), a number of solutions was foundfor kinematic dynamo problems in which velocity field was assumed to be composed of a smallnumber of toroidal and poloidallow-order spherical harmonics. They include T1 and S~ combi­nation of Bullard and Gellman (1954), Tl> S~c and S~ of Lilley (1970), Tn and Sn of Gubbins(1973), S~ and T~c of Pekeris et al. (1973), and T1, S2' S~ and T~s of Kumar and Roberts(1975). After the middle of the 1970's, the focus of interest of dynamo theorists seems to haveshifted to turbulent dynamos and hydromagnetic or dynamic treatments, but the importance ofthe Bullard-Gellman approach does not decrease even today. Kinematic dynamos are useful inunderstanding the interaction between the velocity and magnetic fields. The expansion intopoloidal and toroidal modes is applicable to any solenoidal vector fields, and is useful not onlyin kinematic problems but also in dynamic or hydromagnetic problems. Behaviors of kinematicdynamos have not been satisfactorily explored yet, as shown by the small number of cases forwhich existence of solutions was searched. Moreover, the Bullard-Gellman scheme can beextended to solve the time dependent behavior of the dynamo, so that it can form a basis formore general treatments. Therefore, it is very useful if this analysis is carried out for moreextensive combination of velocity fields.

The reason why the programming of dynamo problem was so difficult in the previous stu­dies is that the the equations obtained from the induction equation using toroidal-poloidal expan­sion (Bullard-Gellman type equations) are quite different depending on the velocity fields chosen.If a new combination of velocity modes is considered, the program should be developed almostfrom the scratch because the equations contain terms completely different from the ones for theprevious choice of velocity fields. It was the essential part of the previous studies of kinematicdynamos to derive the correct equations for the particular velocity field. The program developedin this study performs this procedure automatically, and the possibility of program error was thuseliminated. The method of calculation is essentially that given by Bullard and Gellman (1954)themselves, except that the present program handles general functional form rather than numbersappropriate for each specific case.

With this approach, kinematic dynamo problems can be handled with the same program andwith the same procedures for different combinations of velocity harmonics. The velocity fieldfor a kinematic dynamo problem can be characterized by the modes such as T 1 and S~c, and theshape of the radial function each mode takes. For the present program, the only parametersneeded besides the ones specifying the velocity field are the field we are interested in (usuallythe dipole term, SI), the maximum degree to which the magnetic field is expanded, and thenumber of division of radial distance when the differential equations are approximated by thedifference form. No change is necessary when different velocity harmonics are employed, orwhen the calculation is carried out to a different degree or using a different division number.

2. Method of Analysis

The procedure developed below follows very closely the scheme given by Bullard and Gell­man (1954). We shall only briefly outline the mathematical treatment as is necessary for

8

understanding the computer program developed later. The normalized form. of the inductionequation

oBa;-=Rmcur1(vXB)+V2B (1)

describes the behavior of the magnetic field B in the presence of a velocity field v. In this equa­tion, Rm is the magnetic Reynolds number characterizing the relative importance of the inductionterm (cur1(vxB)) against the diffusion term (V2B). Since both the magnetic field and the velo­city field satisfies the divergence-free condition, they can be expressed as sums of toroidal andpoloidal vectors, which can then be expanded using spherical harmonics (cf., Chandrasekhar,1961). For example, the magnetic field can be expressed as

B=:E (T~+S~)=:E[curl[T~(r)Y ~(e,<l»'!' J+cur12[S~(r)Y ~(e,<l»'!' J] (2)~ ~ r r

where (r, e, <l» are spherical coordinates, T~ and S~ are the toroidal and poloidal vectors ofdegree I and order m, and T~(r) and S~(r) are their defining scalar functions. (Following Bullardand Gellman (1954), Greek letters such as 13 represents, collectively, degree I, order m, and eithersin or cos of <l>-dependence of a spherical harmonic function if it appears as a suffix, and simplythe degree I if used by itself.) Y~(e,<l» are spherical harmonic functions of unnormalized form.Because of the solenoidal nature, the velocity field can also be expanded similar to (2). In thispaper, the suffix ex. is exclusively used to specify the velocity field, to make the distinction frommagnetic field harmonics, which are represented by either 13 or y. A notation Ua' UIl' etc. willbe employed if either toroidal or poloidal fields is implied. Inserting the toroidal-poloidal expan­sion into the induction equation (1), and then we integrate the equation over the surface of asphere of radius r after multiplying by a toroidal (poloidal) function T'y (S'y) which has the sameshape as (2) except that the radial function is unity for every value of r. Because of the ortho­gonality of toroidal andpoloidal fields of different degree and order, the results are simplified as

1. OTy 1.02Ty

r--::;--r--::;-+y(y+ l)Ty=-Rm:E:E[(TaT~Ty)+(TaS~Ty)+(SaT~Ty)+(SaS~Ty)J (3)ot or a ~

1. oSy ? o2Syr -::;--r--::;-+yCY+ l)Sy=-Rm:E:E[(Tas~Sy)+(SaT~Sy)+(Sas~Sy)J (4)

ot or a ~

In these equations, (UaU~Uy) on the right hand side are the interaction terms representing gen­eration of the magnetic field Uy by the action of the velocity Ua on the magnetic field U~.

K(UaU~Ty)=-NY jfUy'curl(UaXUIl)sineded<l> (5)

y

where Ky is r4 or r6/yCY+1), when Ur' is Ty' or Sr', respectively, and Ny is the normalizing factorefor the spherical harmonic. Equations (3) and (4) determine the' behavior of the various modesTy and Sy

Two different approaches are possible for solving these equations. One is to seek for asteady state solution by eliminating the time derivatives and form an eigenvalue problem for Rm,

which was the method employed by Bullard and Gellman (1954). Another is to assume a solu­tion which depends on time as eft. In this case, %t in (3) and (4) is replaced by p, and weobtain an eigenvalue problem for p, with Rm appearing as a parameter.

3. Programming

9

The following shows how to implement the above procedure in a computer program. Forthe programming language, C was used in the first half of the program where algebraic analysisof the induction equation is carried out, and Fortran was employed in the latter half of the pro­gram where actual numerical calculations are carried out. This choice was made because C iswell suited to carry out logical operations using character variables, while numerical calculationscan best be done using Fortran subroutines in mathematical libraries available at most computercenters.

Identification of the Interaction ChainThe first task in the expansion of induction equation is to find which magnetic field is

induced by the given velocity field. As the interaction terms (Ua.U~Uy) depend either on Gauntintegrals Ka.~y (when the number of the toroidal terms in U is 0 or 2) or on Elsasser integralsLa.~y (when it is 1 or 3), the search can be implemented by using the selection rules of the Gauntand Elsasser integrals.

Programming selection rules is quite simple. We start by choosing for the trial function aharmonic U~ which we are interested in (S1> for example). All the harmonics Uy with degreesless than or equal to the preassigned maximum degree are tried to see if it can be induced by thecombination of the velocity Ua. and magnetic field U~. If (Ua.U~Uy) satisfies the selection rulesand if Uy was not used as trial function before, we place the particular Uy in the waiting list.After the search for one U~ is over, the next one is taken from the waiting list, and the searchcontinues in the same manner, until the waiting list is exhausted.

There are rare cases in which the Gaunt or Elsasser integral vanishes for a combination ofharmonics satisfying the selection rules. However, as we need the values of these integrals inany case for constructing the differential equations, appearance of such zeros for the integralsdoes not cause any trouble. The Gaunt or Elsasser integral is evaluated when the selection rulesare satisfied, and the term is discarded if the particular integral vanishes.

The Gaunt and Elsasser IntegralsAs mentioned earlier, we need the values of the Gaunt and Elsasser integrals appearing in

the interaction terms (Ua.U~Uy). For both integrals, the integration by <l> between 0 and 2n givesn/2 times the number of occurrence of zero in the expressions i±j±k.

The Gaunt integral can be evaluated by the the method presented by Gaunt (1929). Thepart in Ka.~y related only to 8 (Gi~) can be written as

1 .

fpi(x)pi (x)P~(x)dx 2(-ly-m-k(m+j)!(n+k)!(2s-2n)!s! L (-l)t(l+i+t)!(m+n-i-t)! (6)-1 m (m-j)!(s-I)!(s-m)!(s-n)!(2s+1)! t (l-i-t) !(m-n+i+t) !(n-k-t) !t!

where 2s=l+m+n, and the summation by t spans integers for which all the factors of factorialsare nonnegative. By applying the recurrence formula of Legendre function, we can show thatthe integral Ei~ (the part of Elsasser integral related only to 8) can be represented by the use ofGi~ integrals.

"k 1 r "1k1 "k] 1 r "1k1 "k]Ei~=2"(m+j)L(m+j-1)Gi{;;'-1 ~ -(n-k)Gi-ln_1 n -2" (n+k) L(n+k-1)Gi~ ';::r(m-j)Gi-ln n-1 (7)

Thus the calculation of integrals is reduced to simple summation of terms by (6) or (7). Onething which needs special care in the calculation of the Gaunt and Elsasser integrals is that thenumerators and denominators in (6) tend to be quite large and the signs of terms alternate.Thus, if ordinary method is employed in this calculation, error may become unexpectedly largedue to the loss of significant digits. The values of Gi~ and Ei~ are always rational numbersas shown by (6) and (7). Using this property, each term of (6) are expressed as products of

10

prime numbers in the present program. This procedure is somewhat cumbersome, but by thismethod the calculations can be carried out in an error-free way.

The values of these integrals were sometimes given in a tabular form, but since its calcula­tion is straightforward as shown above, it is much easier to calculate them when they are neededin the program than to use tabulated numbers.

Evaluation of Interaction TermsThe next step is the formation of the differential equations governing the behaviors of indi­

vidual harmonics. The interaction terms (UaU~U'Y) in (3) and (4) can be represented by theGaunt or Elsasser integrals, <x, ~, y, and a normalization factor. The expressions are fairly easyand are given by Bullard and Gellman (1954).

The only point we should take care is that the velocity and magnetic field functions in theinteraction terms are not necessarily of the form of Ua or U~, but also their first and second r­derivatives and those divided by r. We have to treat these functions symbolically rather thannumerically to keep the generality of the scheme. In the present program, the coefficients ofinteraction terms are stored separately for each combination of one of Ua' Uair, aUalar,aUalrar, a2Ua /a? and one of U~, aU~/ar, a2U~/a?

The results of this evaluation are machine readable form of the expanded equation (3) and(4), with correct coefficients for each interaction term. Therefore, this output can be displayed insuch a way as is understandable to human thinking.

Reduction of Differential Equation into Difference FormSince we are studying only the kinematic problem, any forms of the velocity function

needed in calculation of (3) or (4) (aUa/ar, etc.) can be evaluated exactly, as the velocity radialfunction Ua is given. The differential form of the magnetic field, on the other hand, should bereplaced by approximate difference forms. If the range from r = 0 to 1 is divided into M equalparts, and if the value of particular function U~ at the kth grid point is written as U~.b the equa­tions (3) and (4) can be written at each grid point by applying the following replacements;U~=U~,b aU~/ar=M8', and a2U~/a?=M28", where 8' and 8" are the first and second centraldifferences of U~ at point rk = kiM. In the computer program, the easiest way to realize thisprocedure is to prepare a blank square matrix of necessary dimensions, and to add submatricesformed for the interaction term (UaU~U'Y) (appropriately weighted by the factors obtained earlier)in which differential terms are replaced by the above forms.

Boundary ConditionsThe boundary conditions satisfied by the magnetic field harmonics are that they are not

singular at the origin, that the poloidal field connects smoothly with the field outside the corewhich can be derived from a scalar potential, and that the toroidal field is completely containedin the core. Therefore,

S~=T~=O(r~+l) at r=O, aS~/ar+~S~=T~=O at r=l (8)

For a toroidal component, the radial function T~(r) vanishes at both r = 0 and 1, so that values atonly (M-l) points need to be determined. For a poloidal component, the value at r = 0 alsovanishes but the value at r = 1 should be determined by the boundary condition (8). The expres­sions of derivatives (20) at r=l gives a relation between S~,M-l> S~.M' S~,M+l> which are values ofS~ at r = 1 and its neighboring points. The latter (S~.M+l) is of course fictitious point outside ofthe sphere, but through the boundary condition (8), it can be replaced by S~,M-l and S~,M'

Formation of the Matrix Equation and Diagonalization

11

The matrix formed from the right hand side of the equations (3) and (4) are composed ofsubmatrices of My<M~, where My and M~ are either M or M-1 depending on the boundary con­ditions satisfied by Uy and U~. These submatrices are placed in the big matrix containing all theequations (3) and (4). The second and third terms on the left hand side of (3) and (4), represent­ing the diffusion of the magnetic field, can also be formulated by the same method and the boun­dary conditions can be applied as shown above. The diffusion term thus forms a tri-diagonalmatrix. The time derivatives in (3) and (4) on the other hand, form a diagonal matrix, which iscomposed of simply the values of ? (or (k/M)2, numerically). A matrix equation is derived bythese replacements.

Solving the Eigenvalue ProblemThe eigenvalues Rm or p and the eigenvector of the matrix obtained above can be solved by

using standard library routines. In the present case, Fortran subroutines in MATHJLIBRARY ofIMSL (IMSL, 1987) were used in the computation. In the stationary solution, the smallest realeigenvalue is the one we are seeking. On the other hand, time-dependent case is solved by tak­ing Rm as a parameter. The real part of p usually increases as the magnetic Reynolds number isincreased. The value of Rm at which the real part of p changes from negative to positive indi­cates the onset of instability. If the imaginary part of p is zero, the solution coincides with thesteady state solution. If the imaginary part is not zero, the instability takes the form of oscilla­tion with increasing amplitUde.

4. Application to the Bullard-Gellman Velocity Field

The programs were developed on Sun-3 and Sun-4 Workstations, and transferred to ETA-lOsuper computer, both of which run on Unix operating system. The program was first applied tothe case of T1 and S~c combination which was repeatedly studied since Bullard and Gellman(1954). That this program works correctly is shown by the fact that correct expansion forBullard-Gellman velocities are obtained for degrees 2, 3, 4 (Bullard and Gellman, 1954), and 5(Gibson and Roberts, 1969; with correction in Pekeris et al" 1973). It was also confirmed forthe least positive eigenvalues that the same values can be obtained by both stationary and time­dependent formulations.

Table 1 lists the smallest eigenvalues obtained by various authors for different combinationsof the degree of harmonics and division in radius. Apparently, large difference in eigenvalues isnoticed in a number of cases with the same truncation level and division number. However, oncloser look, it appears that the values reported by Gibson and Roberts (1969) are in most casesvery different from the values reported by others. The present results are in good agreementwith the data of Bullard and Gellman (1954) and of Lilley (1970). The difference between theeigenvalues of these three authors never exceeds 0.5 %. The eigenvalues of Pekeris et al. (1973)are reported to have been obtained by "finite differences, with an interval h of 0.01 or less". Thecoincidence between the present eigenvalues and the ones given by Pekeris et al. (1973) is alsosatisfactory. We can conclude from these comparisons that the present program works satisfac­torily for a wide range of trancation levels (L) and division in radius (M). Among the earlierresults reported for the Bullard-Gellman velocity field, the ones by Gibson and Roberts (1969)are apparently in error.

Figure 1 shows the change of the real part of the eigenvalue p with the change of magneticReynolds number. In the present study, satisfactory coincidence was observed in all the casesbetween the stationary and time-dependent solutions.

5. Conclusions

12

Table 1. Eigenvalues for Bullard-Gellman velocity T\=5r2(I-r), S~=,J(I-r)2

Degree No.ofEqs. Author(s) Division in r

10 16 20 50 100

BG54GR69 66.46

2 4 L70 58.6 64.4PAS73 66.460K89 58.38 63.22 64.38 66.13 66.38

BG54 68.8GR69 83.43 83.09

3 7 L70 67.6 78.5PAS73 83.207K89 68.78 76.60 78.78 82.35 82.90

GR69 76.02 75.954 12 L70 94.31

PAS73 95.834K89 168.90 94.05 94.57 95.60 95.76

GR69 143.25 17 PAS73 1369.2

K89 459.22 305.08 1414.9 1496.8 1434.7

Notes: BG54, Bullard and Gellman (1954); GR69; Clibson and Roberts (1969); L70, Lilley(1970); PAS73, Pekeris et al. (1973); K89, present study.1 Number of division was 17.

Computer programs were developed to treat the induction equation in a general way basedon the principle of computer algebra. Expansion of the induction equation leads to many termswith coefficients which should be determined one by one. In such a situation, evaluation of theequation is very time-consuming and prone to error if interaction terms are evaluated in a con­ventional manner. Present programs avoid this by manipulating the functional forms of variousvelocity and magnetic field harmonics rather than the values of these functions. Because ofmathematically simple structure of poloidal-toroidal expansion and because of the fact that thecoefficients are always rational numbers, error-free expansion of equations is possible by themethod of computer algebra.

Once the equation is correctly expanded, the rest of the program can form the matrix foreigenvalue problem in a straightforward way. Formulation into difference equations, taking careof boundary conditions, and diagonalization needed for making a standard eigenvalue problemcan be carried out without much trouble. Computation was also carried out for the case ofBullard-Gellman velocities and the obtained eigenvalues were compared with the values reportedby other authors. The eigenvalues obtained by the present program are in good agreement withthe values reported by Bullard and Gellman (1954) and Lilley (1970). Satisfactory agreementwas also observed between the present eigenvalues and those of Pekeris et al. (1973), althoughthe details of computation are not known for the latter. On the other hand, data in Gibson andRoberts (1969) are quite different from the present results. It can be concluded that their eigen­values are in error, because the present results are corroborated by comparison with valuesobtained by different workers and different programs.

The merit of present approach lies in the fact that the equations for given velocity harmon­ics can be obtained to any degree without errors. Application of this program to other

13

40

(a) degree 2, division 40

u 0

1 1

2,!!, 0 SI'l... 100

:: 20'""" SO

11 100-1000..:

-10

0 40 80 120 160

Magnetic Reynold. Number

40

(b) degree 3, division 40

u 0

J 1

20 S...

100

:; 20

"" SO11 100-1000..:

-10

0 40 80 120 160

Magnetic Reynold. Number

40

(e) degree 4, division 40

.. --0-- ."

i 'I

~2

0 S

0 10:: 20'""" 50ii 100-1000..:

-10

0 40 80 120 160

Magnellc Reynold. Number

Fig. 1. Change of the largest of the real part of the eigenvalue· p for time-dependent solutionwith the increase of magnetic Reynolds number Rm• The ration of toroidallpo1oidal velocities (e)for each curve is indicated on the right. The number of division in r is 40, and the maximumdegrees are (a) 3, (b) 4, and (c) 5.

14

combination of velocities is now in progress and will be reported elsewhere.The present approach can also be expanded for the hydromagnetic dynamo with inclusion of

Navier-Stokes equation. To do so, the velocity field must also be expanded into a sum of func­tions U(J.> and the equation for the fluid motion can be solved for the unknown values of Ua inthe similar way as the Bullard-Gellman formulation (Frazer, 1973). In this approach, we cannotrestrict the interaction diagram to a small number of velocity harmonics. If the induction equa­tion is coupled with Navier-Stokes equation, the resulting equations will be quite difficult andconventional approaches will fail just because of their complexity. If Bullard-Gellman expansionis extended to such cases, only algebraic treatment of equations by computer can handle theproblem. Otherwise, some different approaches (such as spectral method) are needed to formu­late ever increasing complexities. Further, it is planned to incorporate the equation of fluidmotion in a way as suggested by Frazer (1973). Such extension of the present program will beuseful in studying the behaviors of kinematic and hydromagnetic dynamos.

References

Bullard, E.C. and H. Gellman, Phil. Trans. Roy. Soc. Lond., A247, 213-278, 1954.Chandrasekhar, S., Hydrodynamic and Hydromagnetic Stability, 652pp., Oxford University Press,

London, 1961.Frazer, M.C., Phys. Earth Planet. Inter., 8, 75-82, 1974.Gaunt, JA., Phil. Trans. Roy. Soc. London, A228, 151-196, 1929.Gibson, R.D. and P.R. Roberts, in The Application of Modem Physics to the Earth and Planetary

Interiors, edited by S.K. Runcorn, pp. 577-602, Wiley, London, 1969.Gubbins, D., Phil. Tran. Roy. Soc. Lond., A274, 493-521, 1973.IMSL, MATHILIBRARY User's Manual, Version 1.0, 1149p, Houston, Texas, 1987.Kumar, S. and P.H. Roberts, Proc. Roy. Soc. Lond., A344, 235-258, 1975.Lilley, F.E.M, Proc. Roy, Soc. Lond., A316, 153-167, 1970.Pekeris, C.L., Y. Accad, and B. Shkoller, Phil. Trans. Roy. Soc. Lond., A275, 425-461, 1973.

(in press in Journal of Geomagnetism and Geoelectricity)

15

OPAQUE MINERALS IN HYDROTHERMAL ALTERATION ZONESAND THEIR RELEVANCE TO ROCK MAGNETISM.

Hirotomo UENO

Department of Geology, College of Liberal Arts,Kagoshima University, Kagoshima 890

Introduction

It is important to discriminate TRM and CRM, neverthe­less it is not easy by usual paleomagneical treatments. Thesimplest identification with the CRM may be that the remanence isdue to ferromagnetic minerals which are crystallized newly orrecrystallized from the same minerals during alteration or meta­morphism. In this paper opaque minerals, which are inclusive ofboth primary rock-forming Fe-Ti oxide minerals in igneous rocks,secondary Fe-Ti oxide minerals and new sulfide minerals changedfrom Fe-Ti oxide minerals, are examined in hydrothermal altera­tion zones around ore deposits, and remanences characterized bythese ore minerals are dealt with.

Continuous sections from fresh to altered within thesame igneous rock body are selected for this study.

Volcanic Sulfur Deposits

The opaque minerals in fresh rocks of two pyroxeneandesite lava around the Numajiri volcanic sulfur deposits (38 0

38'N,140 °15'E) consists of primary magnetite with accessoryilmenite. Advancing alteration, magnetite changes partly tomaghemite. In this step the alteration of silicate minerals isslight decomposition of plagioclase and pyroxene. As kaolinite,montmorillonite and jarosite are detected in more altered sites,fine grained Ti rich hematite is formed from maghemite and magne­tite. Opaque minerals in highly altered sites consist mainly ofTi poor hematite with accessory with pseudobrookite, and aluniteis found in these sites. Finally those opaque minerals change tomarcasite (Fig. 1).

The median destructive fields by alternating fielddemagnetization of samples from fresh and altered sites are 10 to20 mT and 50 to over 60 mT, respectively. The CRMs due to hema­ti te in altered sites are harder than the TRMs in fresh sites(Ueno and Nedachi, 1985).

The similar occurrences of Fe-Ti oxide minerals in the

16

Green Tuff alteration zone at the western Gunma and in the geo­thermal alteration zone at Noya have reported by Sato (1984) andFujimoto (1987), respectively. But, they have not mentionedsulfide minerals. Therefore, results described here can beapplied to the region of Green Tuff alteration and geothermalalteration.

Kuroko Deposits

Generally almost rocks around the Kuroko deposits arealtered, but the Torigoe dacite lava around the Kosaka Kurokodeposi ts (40 0 19' N, 140 0 46') and the Hatabira dacite of the Tsu­chihata Kuroko deposits (39 0 17'N,140 0 SO'E) have fresh parts.

VOLCANIC SULFUR DEPOSITS Numajiri Mine)

Ti rich Mt --=::.( Ti poor Mt J--.....,t.:::..( Tpi

b

poor HmJ--_...."'" Marcasite

LMh~ Ti rich Hm I

KUROKO DEPOSITS (Kosaka & Tsuchihata Mines)

Mt -----...."" Hm -----~.... Pyritel -'--__---'~

SKARN DEPOSITS Chichibu Mine

Mt ...."" Mt .....:::.. Pyrite

II.- --_--I~

Fig. 1. Opaque minerals in hydrothermal alteration zones.Mt; magnetite, Mh; maghemite, Hm; hematite,Pb; pseudobrookite

17

The Torigoe dacite lava whose thickness in 68 m underlies theKosaka Kuroko deposits. The bottom and upper one third parts arealtered with pale gray or greenish white in color, but the cen­tral one third part is fresh with brownish gray in color. Thefresh part have relatively fine grained magnetite which is euhe­dral or subhedral .. The most fresh rock include no clay mineral.The altered parts have hematite of needle shape. In this partchlorite and sericite are detected. Finally hematite changes topyri te. The Hatabira rhyolite dome of the Tsuchihata Kurokodeposits is host rock of the network copper veins which arebelieved to the Keiko-type ores of the Kuroko deposits. The mostfresh rock among collected samples is 300m of the ore body at thenear the entrance adi t of Level 0, and the rocks become morealtered as the distance to the ore body decrease. Even if themost fresh part with brownish gray in color primary magnetitechanges partly to hematite along the rim of the grain. As chlor­ite and sericite increase, hematite replaces almost magnetite.Two perlite zones resulted from rapid cooling of original rockappear in the altered zone. Although clay mineral is mordeniteinstead of chlorite and sericite in the perlite zone, hematiteappears as a continuously changing phase of opaque minerals.Finally hematite changes to pyrite (Fig.1).

Samples from fresh and altered parts have normal andreversed polarity magnetizations, respectively (Ueno, 1982). Themedian destructive fields of samples from fresh parts are about10 mT, and those from altered parts are over 60 mT.

Pyrometasomatic Deposits

The Chichibu pyrometasomatic deposits (36 ° 01 'N, 138 °49 'E) have genetical relation to quartz diorite. The quartzdiorite bodies have undergone the different grade of hydrothermalalteration. The fresh parts of the quartz diorite bodies haveeuhedral or subhedral magnetite of 150 microns or less in size.As the alteration increases in grade, magnetite ought to berecrystallized as the aggregate of small magnetite of 10 micronsin each grain size. The recrystallized magnetite contains lessV20 3 , A1 203 and Ti02 (Ueno, 1986). The Curie temperatures are560°C on fresh rock and 580°C on altered rocks. The chemicalcomposition of magnetite is exactly concordant with the Curietemperature, and it seems that recrystallized magnetite becomemore pure magnetite. Finally those change to pyrite (Fig. 1).

The median destructive fields of samples from freshsites are 15 to 45 mT. The magnetizations due t~ recrystallizedmagnetite have the median destructive fields of 60 or over 60 mT(Ueno, 1987).

18

The ore deposits described above are of Miocene toHolocene in age. The older deposits may be examined by the sameprocedure, but the mineral changes in the later stages must beconsidered. There found no typical igneous body including freshand altered parts around vein type ore deposits because of over­lapping of so called propylitization.

Summary

Opaque minerals in the hydrothermal alteration zonearound ore deposits change according to the grade of the altera­tion. And the changing style of opaque minerals are different ineach type ore deposit. That means the opaque minerals are re­flecting upon the conditions during alteration. It is clear fromthe results that volcanic sulfur deposits and Kuroko deposits arehigher oxidation state than pyrometasomatic deposits.

As mentioned above it is sure that median destructivefields of the CRM acquired during hydrothermal alteration ishigh as compared with the original TRM.

References

Fujimoto, K.(1987) Jour. Faculty Sci. Vniv. Tokyo, Sec. 2, 21,257-282.

Sato, W. (1984) Chikyu Kagaku (Earth Sci.), 33, 161-181.Veno, H. (1982) Sci. Rept. Tohoku Vniv., Sere 2, 15, 273-280.Veno, H., Nedachi, M. (1985) Rock Mag. Paleogeophys., 12, 66-71.Veno, H. (1986) Rock Mag. Paleogeophys., 16, 60-65.Veno, H., Tonouchi, S. (1987) Econ. Geol., 82, 1723-1731.

19

THERMAL VARIATION OF INITIAL SUSCEPTIBILITY BY USINGAUTOMATIC HIGH-TEMPERATURE SUSCEPTIBILITY METER

Masayuki TORII"~ Hirokuni ODA" and Hidetoshi SHIBUYAt

"Department of Geology and Mineralogy, Kyoto University, Kyoto 606.tDepartment of Earth Sciences, The University of Osaka Prefecture, Sakai 591.

Thermal demagnetization is a very powerful technique to remove secondaryoverprintings of remanence either of low-blocking or high-blocking temperaturecomponents. However some of the minerals in the rock samples turn magnetically orchemically unstable during thermal cleaning to a few hundred degrees in Celsius.Thermal instability of the magnetic minerals often degrades usefulness of thermaldemagnetization and shows a confusing pattern on the vector diagram (Fig. 1).Titanomaghemite, pyrrhotite, and goethite are typical minerals of thermally unstablenature. Main difficulty may come from the fact that those minerals convert to magnetiteduring the heating experiment. Newly formed magnetite can easily override the primaryremanence due to its very large magnetization. Growth of magnetite during the artificialheating is generally prominent for the case of unconsolidated sediments because. of thepresence of reducing agent, dehydration, and less abundance of primary stable magneticminerals.

Thermal demagnetization is a very time-consuming procedure and destructiveexperiment. By these reasons it is practically important to know prior to thermaldemagnetization whether the samples can survive the thermal treatment or not. It is alsohelpful to know the maximum temperatures to be allowed for each particular sample.There are numerous, well-established laboratory techniques for indicating thermalvariation of magnetic property during the heating. Thermally sensitive parameters are asfollows: Curie temperature, coercivity spectrum of isothermal or anhysteretic remanence,remanent coercivity, rotational hysteresis, initial susceptibility, and so on (e.g., Lowrie andHeller, 1982; Collinson, 1983). The initial susceptibility is one of such parameters and hassome advantages for practical use. Firstly the initial susceptibility is sensitive to theportion of finer magnetic particles which may carry stable part of remanence. Secondlymeasuring thermal change of the initial susceptibility is simple and less time-consumingparticularly by using an automatic high- temperature susceptibility meter system.

We employed Bartington M.S.2WIF system which is a very common commerciallydeveloped high-temperature susceptibility meter. It has very sensitive sensor which enableus to measure less magnetic samples such as sediments; the noise level is about 1X 10-8 in SI

20

200Stepwise heating

N

iii 150<XlIw

0~ ... 12.3b~ 100 ... 32.2c

~ ~ 33.2ca.Q)

~ 39.2cuOJ 50:l

Vl .Q. 48.3c

... 55.3c

00 100 200 300 400 500 600

Temperature

RT

S_I-----"-i<F~-F300-'------+--+-3~G >.., ,\ 5x 10-' Nm'.::: • 57O"~,o

4009' ...

,t· .......

~e0 .....

bE Dn RT

60~""'"

39.2c

Fig. 1 (left) Unsuccessful thermal demagnetization at the higher temperatures (above300°C). Sample is a marine siltstone from the Boso peninsula (Pleistocene).

Fig. 2 (right) Initial susceptibility measured after each step of progressive thermaldemagnetization for six samples from the Boso peninsula. Initial susceptibility increasesabove 350 0 C.

unit. For high-temperature measurement, sample should be prepared as a cylindricalshape of 15 mm in diameter and 25 mm highs. A furnace controller unit is equipped with aRS232C port through which we can transfer read out of susceptibility and temperature.However we could not control susceptibility meter through the RS interface such as to stopheating or to preset maximum temperatures. This one-way communication system forcedus to keep watching the thermometer during heating process and to switch the powercontroller towards cooling at the turning temperatures. We therefore made someimprovement to the electric circuit to enable automatic switching of the furnace throughRS interface. The adhon circuit is, in practice, very simple one and we do not thinknecessary to show the circuit diagram in this report. The interfacing program is coded withTurbo Pascal (ver. 5.0), and the diagrams are illustrated by using Microsoft Chart (ver. 3.1).

Thermal change of the initial susceptibility can be observed through measurementof the susceptibility after every steps of progressive thermal demagnetization as shown inFig. 2 The figure is a case of Pleistocene marine sediment form the Boso peninsula. Wecan find pronounced increase in susceptibility by heating samples above 350·C. We can,however, know the change only after thermal demagnetization.

Continuous change in the initial susceptibility is observed during heating by usingthe automatic high-temperature susceptibility meter (Fig. 3). Heating and cooling rate iscontrolled as 10·C/min. Sudden increase in susceptibility appears at 350·C and 500·C on

21

500

450

........ 400(f)

IX) J50I~ JOO...........

heating (22.1 a)

.".\

>- 2S0~

:Q 200-+Ja.8 150(Il::l

(f) 100 (X 10->-) • _...._-_••

.-.---....... ,,

600500200100

\'.... ._.- ..__..,~ ----. --

•• o?>: .."'.¥' ••"->J'I"< """' _ ~ __ __ ~ __._~ >~'::.~:~~..\o'Oo.~~ ..

oo

so

JOO 400temperature

Fig. 3 Variation of initial susceptibility during continuous heating up to 350·C. Heatingcurve is exaggerated by ten (indicated by X 10) to show increase of susceptibility. Coolingcurve is completely irreversible compared to the heating curve.

600500400200

Continuous heating (26.1 a)

100

150

:Q-+J

fr 50o(Il::l(f)

(f)

!f 1COwo...........

JOOtemperature

Fig. 4 Stepwise, continuous variation of initial susceptibility recorded by automatichigh-temperature susceptibility meter. Irreversible change observed by heating above300·C.

22

heating process. Increase in susceptibility is much enhanced on the cooling curve. Thissample clearly showed irreversible change of the initial susceptibility at high-temperatures(above 350°C).

Thermal change in susceptibility is more clearly observed with stepwise, continuousheating experiments; to heat up sample to.a certain temperature and to cool down to theroom temperature, and then to repeat heating/cooling cycles at the higher temperatures(Fig. 4). This progressive experiment is more similar to the actual condition of thermaldemagnetization experiment. We can point out the temperatures above which thesusceptibility makes irreversible change by heating.

Our tentative conclusion is that we cannot safely carry forward thermaldemagnetization above the irreversible point indicated by the continuous high-temperaturesusceptibility measurement The high-temperature susceptibility measurement can serveas a time-saving technique in terms of a reconnaissance of thermal demagnetization.

Reference:

Lowrie, W. and F. Heller (1982) Rev. Geophys. Space Phys" 20, 171.

Collinson, D.W. (1983) Method in Rock Magnetism and Paleomagnetism, (Chapman andHall, London), 503.

23

AN AUTOMATIC SPINNER MAGNETOMETERWITH TIIERMAL DEMAGNETIZATION EQUIPMENT

Masaru Kono, Masayuki HOSHI1, Koji YAMAGUCHI2, and Yosuke NISHI3

Department of Applied Physics, Tokyo Institute of TechnologyOokayama 2-12-1, Meguro-ku, Tokyo 152

1. Introduction

Spinner magnetometer is a very useful instrument and widely used in rock magnetism andpaleomagnetism. Some of the important steps in its development were the introduction offluxgate magnetometer with phase sensitive circuit by Foster (1966) and that of the ring-coresensor by Molyneux (1971). In paleomagnetic measurements, it is necessary to replace the sam­ple several times to obtain three components of the magnetization vector. Moreover, measure­ment of magnetization cannot be considered complete without appropriate magnetic cleaningsuch as alternating field (AF) or thermal demagnetization. Because the measurement ofremanence and demagnetization is very time-consuming, several attempts have been made toautomatize either the measurement itself (e.g., Kono et al., 1981), or the entire process of meas­urement and demagnetization (e.g., Noel and Molyneux, 1975; Niitsuma and Koyama, 1989).

Kono et al. (1981) constructed a spinner magnetometer in which the sample is rotatedaround two axes simultaneously, and the signal from a single ring-core fluxgate sensor suppliessufficient information about the magnetization of a sample. This was made possible because thevertical component of the magnetic field measured on the surface of a sphere completely deter­mines the potential field outside, as they satisfy the classical Dirichlet condition. Samplereplacements were made unnecessary by the rotation of the sample around the two orthogonalaxes (vertical and horizontal) by the use of bevel gears. For further automation, this instrumentmay be combined with alternating field (AF) demagnetization. But it is practically impossible tocombine this with thermal demagnetization because of the mechanical complexity.

As sophisticated demagnetization techniques became needed to characterize different com­ponents of magnetization, thermal demagnetization seems to have gained importance comparedwith AF demagnetization, as the latter is often useless for rocks containing very high coercivitycomponents such as hematite. To include thermal demagnetization in an automatic system, it isnecessary to make the mechanical parts as simple as possible to avoid damages caused by theheating, or the sample and the moving mechanism should be well separated so that heating doesnot affect the mechanical components.

We have designed an automated system in which a sample is rotated and translated and thesignal is measured by a fluxgate sensor. In contrast to the scheme of Kono et al. (1981), thepresent magnetometer measures the field over the surface of a cylinder surrounding the sample.In principle, this method gives the complete description of the potential field by a source withina cylinder only when the vertical component is measured over the infinite stretch of the cylinder.In practice, however, the magnetic moment of a sample can be determined to a satisfactory levelby measureing the field over a short distance in the axial direction even when it contains a con­siderable amount of multipole fields, e.g., quadrupole and octapole terms. We incorporated ther­mal demagnetization as a part of automatic operation, with an electric fumace placed in a three-

1 Now at Sony Corporation, Kita-Shinagawa 6-7, Shinagawa-ku, Tokyo 141.

2 Now at Kawasaki Steel Corporation, Uchisaiwai-cho 2-2, Chiyoda-ku, Tokyo 100.

3 Now at Yamatake-Honeywell Electric Corporation, Shibuya 2-12, Shibuya-ky, Tokyo 150.

24

layer permalloy shield well separated from the sensor. We shall describe below the method ofdetermination of remanence direction and intensity, and also give brief descriptions of the elec­tric circuit and mechanical setup, and some examples obtained by this instrument.

2. Determination of Magnetic Remanence

(1)

(2)nm

The magnetic potential of a sample can be expressed by expansion into spherical harmonics~ n C

W=cI, I,(_)n+1p~(cose)(a~cosm<!>+b~sinm<!»_lm=O r

where c is some length scale included to make the dimension of a~ and b~ that of the field,(r,e,<!» are spherical coordinates with the origin placed at the center of the sample and the polaraxis taken along the sample rotation axis, p~(cose) are associated Legendre functions, and a~

and b~ are the Gauss coefficients describing the magnetic moment of the sample. In our case, itis more convenient to use the cylindrical coordinated (s,z,<!». The three components of the mag­netic field at the surface of a cylinder of radius c can be obtained by partial differentiation of thepotential W by these coordinates.

Bs=I,Dinn+1e[(n+1)p~(cose)-(n-m+l)cOsep~+l(cose)](a~cosm<!>+b~sinm<!»

B z=I,I,(n-m+1)sinn+2ep~+1(cose)(a~cosm<!>+b~sinm<!»nm

(3)

Bq,=I,Lmsinn+leP~(cose)(a~sinm<!>-b~cosm<!»nm

(4)

Obviously, axially symmetric terms in the potential (m=O) does not contribute to the fieldcomponent Bq" so that we cannot obtain any information about them from the measurement ofthe <!>-component of the magnetic field. On the other hand, it is possible to determine the poten­tial either from z-component or s-component or from both. If the sample is rotated at a fixedvalue of z, a non-axisymmetric term (m:;e()) produces a signal which is sinusoidal with periodsequal to the time for one revolution divided by m. Distinction between terms with different mcan therefore be made easily by frequency sensitive analysis such as the fast Fourier transform(FFT). The distinction between the terms with differentn can only be made possible through theanalysis of the z-dependence of the magnetic field. Unfortunately, the signals corresponding todifferent n are not orthogonal to each other in contrast to the case of the sampling over the sur­face of a sphere (Kono et a1., 1981). Therefore, the Gauss coefficients ~ and b~ will change ifthe level of truncation in n is changed. It should be noted, however, that the components of themagnetic field are either even or odd function of z. Since even and odd functions are orthognalto each other if the interval of measurement is taken to be symmetric about z=O, the presence ofthe quadrupole term (n=2) does not hinder the precise determination of the dipole term (n=l).The source of largest error in the determination of the dipole term is obviously the octupole termwhich has similar dependence on z as the dipole term. We found out that the magnetization ofthe sample can be determined satisfactorily from the measurement of the magnetic field by thefluxgate sensor when the sample is rotated around and translated along an axis at the same time.

3. The Spinner Magnetometer

Figure 1 shows a schematic drawing of the magnetometer-furnace system. The rotation andtranslation of the sample are carried out by two stepping motors mounted about 50 cm awayfrom the sample. The stepping motors are actuated by the pulses sent from the computer.

25

Rack Pinion

FanStepping motor {or translation

Stepping motor {or rotation

Air ductSolenoidal coil

Photo interrupter {or rotation

Plastic Supporter

• Fluxgate sensor Herical gears

/Photo interrupter for translator

Ceramic shaft

Three-layer permalloy magnetic schield case

Fig. 1. Schematic diagram of the spinner magnetometer-electric furnace system developed in thisstudy.

Counterclockwise or clockwise rotation of 0.2-3 revs/s, or translation to the left or to the rightwith a speed of 0.4-5 crn/s, or their combination can be attained through the computer control.A fluxgate sensor of ring-core type is located in the middle of the non-magnetic field inside thethree-layer shield. The sensor measures the s-component of the magnetic field in the presentsetup.

In the measurements, the axisymmetric components of the magnetization (a~ is harder toobtain than the other components because it induces only DC magnetic field and because themagnetometer shows a non-negligible amount of drift. Non-axisymmetric terms give frequencydependent signals and therefore can well be determined. The axisymmetric terms can only bedetermined from the variation with z. It is necessary to repeat more translation than rotation inorder to effectively reduce the noise due to the drift.

Figure 2 shows the wave forms of the axisymmetric component for various stackingnumbers when a sample was measured by this magnetometer. This component contains the larg­est noise as indicated above. Obviously the stacking is quite effective in reducing the measure­ment noise. The RMS noise is reduced as the inverse square root of the stack number, as itshould if the noise is random. In practice, too large stack numbers are not practical as the sam­pling time becomes too long. Stack numbers less than about 40 is used in actual measurement.

4. Furnace Control

An electric furnace with noninductive winding is placed further away in the shield case,well separated from the fluxgate sensor in order to avoid the heating of the latter. The blockdiagram of the furnace control circuit is shown in Figure 3. The current to the furnace is con­trolled through a zero-cross solid-state-relay (SSR). The temperature is monitored by a Pt­Pt13%Rh thermocouple of which voltage is read into the computer through 12-bit AD converter.After the necessary linearization, the temperature shown by the thermocouple is compared withthe target temperature.

The computer calculates the necessary output power in terms of proportional action (P),

26

:::r--{\ r\"'~ A /\'1. yV v v0.00

00'002'~ (\'"': 2. ~ f\ 1\'4. ~\I\j v ·.....,...,.,v v

0.00

0.04 scack= 4

'''~''~0.00

.,,~ r\"'~ 8 ~ ~ (\~0.02~VV'V ~ \]V0.00

.,,~ r\'"'~ 16~ 6 (\~""~VV 'C7 '? \lIT

0.00

Fig. 2. The axisymmetric component of magnetization measured with various stacking numbers.Note the change in the zero level, which reflects the long-term drift of the DC level of the mag­netometer.

integral action (I), and derivative action (D). The output power to the furnace is thus the sum ofPill actions. The combination of these three actions improves the performance of the furnacewell if the parameters are suitably chosen. In the actual program, we use a formula written inthe discrete form

1 nPn=kp[En+- LEj+Td(En-En_l)/Ot] (5)

Tij=m

where Pn and En are the output and the deviation at the nth step, respectively, and Ot is the inter­val between the steps. The numerical parameters in the above equation (kp , Ti, Td) were deter­mined empirically, so as to optimize the performance. This power is applied to the furnace byswitching on the mains supply for certain numbers of half cycles in total of 128 cycles of themains supply and switching off for the rest of period. It was shown that the highest temperatureis quite close to the set temperature at every step, and also that the paired heatings show the

27

temperature changes almost identical with each other. This reproducibility is the most importantcharacteristics requied of a furnace used in paleointensity experiments (Thellier and Tehllier,1959).

5. Discussion and Conclusions

An automatic magnetometer-furnace system was built which can operate a series of thermaldemagnetization or magnetization experiments with the computer control. It was shown that,with the combination of rotation and translation of a sample along an axis, it is possible to deter­mine the vector magnetization to a satisfactory level. By this approach, the need to change thesample orientation in measurements was eliminated, and therefore the possibility arise to measureand demagnetize the sample without removing it from the sample holder.

As the needed movements (rotation and translation) are quite simple, the actuators for themovements (stepping motors) and sensors to measure the position (photo-interrupters) can beplaced well separated from the sample. This has a merit in reducing the noise caused by theseelements, as well as in permitting to construct the sample holder and the shaft with a heat resis­tant material such as ceramics. Thus, the sample can be translated to the inside of the furnace

I A ! 1AC 100V

W y (8SSR SSR

Heater

~100 HzData -c;. )

8 bitlatch Clock f"c:l :7'.Comperator,c::.:> }., register Counter Osdlator~)

~

~

SOlenoid~Computer I(NEC PC9801)

Counter Statns

I SSR

~

12bit

AID / Constanti- DC

converter

~ - 'Supply

~

Fig. 3. Block diagram of the electronic circuit controling the temperature of the furnace, appliedmagnetic field, and electric fan for cooling the sample and the furnace.

28

and heated to high temperatures, enabling the combination of heat treatment and measurement tobe carried out successively.

We used this system for paleointensity experiments and found some improvements over theones done by using conventional instruments. First of all, because the sample is never removedfrom the sample holder during the course of an experiment, sample orientation errors are practi­cally eliminated. Secondly, the sample stays inside the three-layer magnetic shield all the time,so that the effect of unwanted magnetic field is small compared with the ordinary experiments.This apparatus may also be useful for thermal demagnetization of viscous samples which acquirelarge remanences in the laboratory. Thirdly, it is possible to perform demagnetization in a goodvacuum to avoid chemical changes by sealing the samples inside a quartz capsule. There is noneed to place the entire system in vacuum.

There are still some shortcomings which need improvement. They include raising the sensi­tivity and reducing the noise level of the sensor, shortening the tum-around time by cooling withwater or with compressed air circulation. All of these points are technically feasible. We hopeto improve the system with such considerations in a near future.

References

Foster, lH., Earth Planet. Sci. Lett., 1,463-466, 1966.Kono, M., Y. Hamano, T. Nishitani, and T. Tosha, Geophys. l R. Astr. Soc., 67,217-227, 1981.Molyneux, L., Geophys. J. R. Astr. Soc., 24, 349-372, 1971.Niitsuma, N. and M. Koyama, paper presented at IAGA General Assembly, Exeter, 1989.Noel, M. and L. Molyneux, Geophys. J. R. Astr. Soc., 43, 1017-1021, 1975.Thellier, E. and O. Thellier, Ann. Geophys., 15,285-376, 1959.

(submitted to Journal of Geomagnetism and Geoelectricity)

29

ARCHEOMAGNETIC INVESTIGATION OF OHDATENO REMAININ AKITA PREFECTURE

Tadashi NI8HITANI and Chihiro 8HIMURA

Institute of Mining Geology, Mining College,Akita University, Akita 010 Japan

Archeomagnetic investigations were performed at OhdatenoRemain. Ohdateno is in the northern part of Aki ta prefecture(Fig.l). Figure 2 indicates an arrangement of houses andfurnaces. Total 145 specimens were collected in 13 furnacesusing a plastic case. An archeological age of this place areinterpreted in 10 to 11 century. Chronologically differentstages gathered there. 81-14 cuts the area of 81-17 and 81-17cuts that of 81-18. The sequence of age, therefore, can beinterpreted as 81-18, 17 and 14. We tried to specify itsorders and studied the relations between archeological ages andarcheomagnetic results.

We .tried to specify their orders and studied the relationsbetween archeological ages and archeomagnetic results. Threepilot samples from each furnace were demagnetized progressivelyup to a peak alternating field of 45 mT and an optimumalternating field was determined. Other specimens weredemagnetized using above optimum alternating field. Fig.3shows some results of this treatment.

Fig.l Ohdateno is in the northern part ofAkita Prefecture in Japan.

30

Fig.2 Samples were collected in the furnaces. SI meansa house. An oval-shaped mark indicates a furnace.All samples were collected from the furnaces.

N51-04

51-06

w

0.

+

~$."...

+

Fig.3 Examples of results obtained after alternatingfield demagnetization. Mark (+) indicate meaninclinations and declinations. a 95 confidencecircle is also indicated.

31

Table I summarized the results. Figure 4 showed the meaninclinations and declinations. We applied correction indeclination and inclination values, which were determinedassuming that the Earth's magnetic field is a dipole field, tothe results of Hirooka (1971). It may be concluded that 81-17and 81-15 are older than others.

ReferenceHirooka, K. (1971) Mem. Fac. 8c i • , Kyoto Un i v • , 8er. Geol.

Mineral., 2.§., 167.

Table I Archeomagnetic results of Ohdateno remain.

8ample N Dec Inc k u 95

81-15 7 -12.366 54.164 147.853 4.98181-06 19 5.682 49.217 105.937 3.27681-14 4 2.896 52.124 373.149 4.76381-15' 5 5.505 60.501 54.118 10.49481-04 14 3.592 54.404 213.753 2.72581-04' 5 12.633 51. 526 21.046 17.06981-03 6 6.259 50.379 260.067 4.16281-01 7 1. 033 55.417 24.523 12.43381-13 3 30.221 54. 004 24.304 25.56881-07 6 21.113 53.261 92.353 7.00881-08 7 11. 719 50.310 292.175 3.53781-05 10 12.810 53.049 57.225 6.44081-17 3 -16.256 49.860 65.121 15.402

DECLINATION

N

~tJo

Fig. 4 Results of mean inclinations and declinations.

32

A GEOMAGNETIC EXCURSION RECORDED IN A STALAGMITE (SPELEOTHEMS)COLLECTED FROM WEST AKIYOSHI PLATEAU, JAPAN

Hayao MORINAGA1, Ikuko HORIEz, Haruko MURAYAMAz, and Katsumi YASKAWAz

1. The Graduate School of Science and Technology, Kobe University, Nada,Kobe 657, Japan

2. Faculty of Science, Kobe University, Nada, Kobe 657, Japan

Figure 1 Schematic view of thevertical section of the stalagmitesample, showing three clear growthlayers (hiatuses).

lSA

------ 16 em -------

NNn3

1. IntroductionThe existence of the geomagnetic excursion has been demonstrated

mainly by paleomagnetism of sediments and partly by paleomagnetism ofvolcanics. A few problems, however, have been indicated; the possibilitythat magnetic phenomenon like an excursion is spuriously recorded inunconsolidated sediments because they are easy to distort physically andthe lack of 'temporal consistency' and 'spatially consistency' of proposedexcursions (Verosub and Banerjee, 1977).

Some excurs ions detected in sediments and volcanics; Mono Lakeexcursion (Denham and Cox, 1971) and La Champ excursion (Roperch et al.,1988) may be true phenomena of the geomagnetic field. Some interests arestill unclear; their occurrence was global or regional, how was theirfine-scale behavior, when they occurred and how long they lasted? This iscaused by detection of excursions in unconsolidated sediments whoseremanent magnetization seems to be a result of a convolution integral ofthe geomagnetic field variation and a moment fixing function (Hyodo,1984), and in volcanics which record only a short-time aspect of thegeomagnetic field. It is very important to detect a high-quality recordof excursions in continuously growing materials with a high time­resolution.

Speleothems (secondarydeposits of limestone cave)continuously grow like sediments.Small amount of magnetic particlesare mixed into their growth layersand carry stable remanentmagnetizations. Somepaleomagnetic studies (Latham etaI., 1986; Morinaga et a1., 1989)have reported that the remanentmagnetization of speleothems is afossil of the geomagnetic field atdeposition of thin growth layersof calcium carbonate and thatspeleothems are useful forclarifying the past geomagneticfield variation.

We got a stalagmite (one ofspeleothems) collected from anunnamed limestone cave in WestAkiyoshi Plateau, YamaguchiPrefecture, Japan through asouvenir processing company. Whenwe investigated the magneticstability and the reliability ofthe remanent magnetization of thesample, we detected the magneticrecording like a geomagnetic

33

excursion.

2. Stalagmite sample and magnetic measurementThe stalagmite had a conical (a hanging bell like) shape, with a

diameter less than 16 em and a height of 22 cm (Figure 1). Three cleargrowth layers were observed by visual inspection. These clear growthlayers may correspond to growth hiatuses. The stalagmite sample waseasily divided into blocks at two of three clear growth layers; outer andinner layers. This suggests the existence of considerably long-periodgrowth hiatuses. As the outer (younger) part of a few centimeter thickthan the outer clear growth layer had been almost stripped and lost whenwe got the stalagmite sample, we were able to obtain the geomagneticinformation in the corresponding period. The center part of thestalagmi te sample is whitish owing to a very small amount of impuritiesand therefore is not suitable to measure its remanent magnetization.234U/230Th dating method was performed on the sample taken out from thecenter part.

Four time-equivalent samples were drilled from the stalagmitesample; one of them drilled vertically and three drilled horizontally.Each drilled sample was of 2.5 em diameter and 6.5-- 11. 5 em in length.The growth layers of time-equivalent sa.mples had similar patterns, so thatsimultaneous growth layers could be identified in respective samples fromtheir characteristic patterns. The growth layers' patterns for foursamples (ISA-1, -2, -3 and -4) are shown in Figure 2. These four sampleswere cut by a diamond blade into 96 thin disc subsamplesof 2.0-- 3. a mmthick in order to measure their remanent magnetizations.

Magnetic measurements were carried out using a cryogenicmagnetometer whose sensitivity is 10- 11 Am 2 . Progressive alternatingfield demagnetization (AFD) was performed on all disc subsamples in orderto examine the magnetic stability and to define the characteristiccomponent of their magnetization. During the progressive AFD, only 6 discsubsamples, which had weaker remanent magnetization intensities by one totwo orders than normal subsamples, showed no stable component andtherefore was not used in latter discussion.

All the rest subsamples had a fairly to rather stable component.The directions of the components changed only slightly duringdemagnetizing up to 40 mT (partly up to 80 mT) and showed a Fisherian

ISA-4 ISA-3 ISA-2 ISA-1

34

Figure 2 Growth layersobserved in four drilledsamples. Lines indicatecorrespondence of simultaneousgrowth layers and solid linesindicate correspondence ofclear growth layers(hiatuses) .

distribution on the stereographic net. We determined the AF level rangeof the Fisherian distribution of the direction on the net by visualinspection and calculated the characteristic direction for eacb subsample,which was a unit vectorial average of the data after AFD in the AF levelsof the range.

3. Results and discussionThe characteristic direction variations along the drilled sample

axes were consistent with each other, according to the correspondence ofgrowth layers observed for four drilled samples. Consistency of thepaleomagnetic results for a vertically drilled sample with those for threehorizontally drilled samples implies that the remanent magnetization ofthe stalagmite is apparently unaffected by dip of the stalagmite surface.The positions of all subsamples were adjusted to distance from the surfaceof a 'master' sample (ISA-4) by stretching and compressing the data. Allthe results of direction (relative declination and inclination) for 90subsamples are shown in Figure 3. Solid lines in this figure showsmoothed variations by the vectorial running-means method of a 5.0 mmlength, shifted with a 2.5 mm step. Arrows in this figure indicate thepositions of growth hiatuses identified by visual inspection. Theintermediate clear growth layer may not correspond to so long-periodgrowth hiatus, because of the smooth change of the direction data at theposition.

In the inner {older} part than the clear growth hiatus of 6.5 cmdistance from the surface, relative declination rotates by about 180' and

DEC. sediment

180

o III

-60 I

1007

j:. ~~~ .I~T::~I.T.Y t(A~'). !

10-9 1 ..:~·

10-11

000

000

sediment

ISA stalagmite

-20

I SA stalagmite

o+--.,---,I-t-+.-+-+-_8+--_

20

INC.

"F i'-.;FP-·; , 1\ ./\

/\f'... J\'/ ,>0'\')" ',L f'J \ ./\ 'v VI ,,'d. 1;< y 3

2000 4000 6000 8000 10000

" > 1\ ;C" "!'.' I 'C'/' ; A

fI " ;/ ,,\ 'C.;'; \. 1\I , ,v ':--' , . •••• \ 1\ ~.A

V ,}'-'i' ., '" "

I{~ \ fI,'.'<" ..' ·Y.\! ... " \ 1\

\1/ \r\,"2000 -4000 6000 8000 10000 12

10(em)

..

00 ,

o 0

GROWTH

;

? HIATUS:Ill

, II I

DECLINATION (.)

60

120

Figure 3 Direction data of 90subsamples from four drilled sample.In the older (inner) part than theinner growth hiatus, the directiondata gradually rotate in an oppositedirection.

20

Figure 4 Tentative correlationbetween the direction variation forthe stalagmite described in thepresent study and that (shaded zone)from paleomagnetism of unconsolidatedsediments (M. Hyodo, personalcommunication) .

35

-t---+--j90W

180

Figure 5 Equal-area plot of thevirtual geomagnetic poles from thestalagmite described in the presentstudy.

90E t---t-----t--References

Denham, C.R. and A. Cox (1971) EarthPlanet. Sci. Lett., 13, 181.

Hyodo, M. (1984) J. Geomag.Geoelectr., 36, 45.

Latham, A.G., H.P. Schwarcz, and D.C.Ford (1986) Earth Planet. Sci.Lett., 79, 195.

Morinaga, H., H. Inokuchi, and K.Yaskawa (1989) Geophys. J., 96,519.

Nakajima, T., K. Yaskawa, N.

sign of inclination becomes reversed. This suggests the existence of somegeomagnetic reversal recorded in the stalagmite. The direction variationfor the outer (younger) part than the position of about 6.5 cm distancefrom the surface is fairly well correlated with the geomagnetic secularvariation record for 4000 years of 6500 to 2500 yr. BP (Figure 4), whichhas been obtained from paleomagnetism of unconsolidated sediments in Japan(Masayuki Hyodo, personal communication). This fairly good correlationshow that the inner growth hiatus was over 6500 yr. BP and that thegeomagnetic reversal occurred at the older time before 6500 yr. BP. Theinner growth hiatus may correspond possibly to the last glacial period,when ground water scarcely flowed into the limestone cave. The growthlayers recording the geomagnetic reversal may correspond possibly to theformer interglacial period.

A 234Uj230Th age for the whitish center part is about 302 (+inf.,-123) kat Because of the low isotopic ratio of 230Th/232 Th (11.2), whichindicates probably a contamination of the dated sample by detriticsediments with the possibility of a source of 230Th different from adisequilibrium source, it is possible that the age is between 300 and 350ka but the most probably is older. The 234U/230Th dating method wasperformed on the growth layers recording the geomagnetic reversal.However, the analysis of the sample had no good result because of the verylow 230Th/232 Th ratio of 4.5, which indicates the possibility ofcontamination by detri tic Th. Datations were made by CERAK, Centred'Etudes et de Recherches Appliquees au Karst, Faculte Polytechnique deMons, rue de Houdain, 9, B-7000 MONS- Belgique.

On the basis of this age, the geomagnetic reversal seems to be anexcursion younger than 300 to 350 Ka. Some excursions (or events) havebeen detected in a sediment core from Lake Biwa; their ages are about 18,49, 110, 180 and 295 Ka (Nakajima et al., 1973; Yaskawa, 1974; Yaskawa etal., 1973). The detected excursion in the stalagmite may correspond toone of them, although the correspondence can not be defined.

Anyhow, it is very significant to detect a geomagnetic excursion(reversal) in other material different from unconsolidated sediments andvolcanics. The geomagnetic reversal is situated at the distance of 7...... 9cm from the surface. On the basis that the younger (outer) part than theinner clear growth layer (hiatus) of 6.5 cm distance from the surface maycorrespond to duration of about 4000 years. duration of the geomagneticreversal can be calculated to beabo u t 1 200 yea r s . The vir t u a 1 VGP 0

geomagnetic pole during thegeomagnetic reversal passed nearlyalong the meridian on Japan from theSouth hemisphere to the Northhemisphere (Figure 5).

36

Natsuhara, N. Kawai, and S. Horie (1973) Nature Phys. Sci., 244, 8.Roperch, P., N. Bonhommet, and S. Levi (1988) Earth Planet. Sci. Lett.,

88, 209.Verosub, K.L. and S.K. Banerjee (1977) Rel'. geophys. Space Phys., 15, 145.Yaskawa, K. (1974) Paleolim. Lake Biwa Japan. Pleist., 2, 77.Yaskawa, K., T. Nakajima, N. Kawai, M. Torii, N. Natsuhara, and S. Horie

(1973) J. Geomag. Geoelectr., 25, 447.

(To be submitted to J. Geomag. Geoelectr.)

37

PALEOENVIRONMENTAL SECULAR CHANGE IN CH'I-LIN-TS'O, TIBETAS INFERRED FROM PALEOMAGNETISM AND STABLE ISOTOPE ANALYSIS

Chizu ITOTAl, Hayao MORINAGAl, Minoru KUSAKABE2,Fumiyuki MURATA1 , Satoru YAMAGUCHI 3 , Nobuhiro ISEZAKI4, Hiroya GOT05,

and Katsumi YASKAWA4

IThe Graduate School of Science and Technology,Kobe University, Kobe 657, Japan

2Institute for Study of the Earth's Interior,Okayama University, Misasa 682-02, Japan

3Teikoku Women's Junior college, Moriguchi Osaka 570, Japan4Department of Earth Sciences, Faculty of Science,

Kobe University, Kobe 657, Japan5Faculty of Liberal Arts and Sciences, Kobe University, Kobe 657, Japan

Ch'i-Lin-Ts'o (Siling Co) is a closed lake in Tibet, China. InAugust 1988, bottom sediments were collected from Ch'i-Lin-Ts'o using apneumatical piston corer with an aim to obtain useful information ofpaleoenvironmental secular change in Tibet.

Three cores were collected; CH8801, CH8802 and CH8803. Two coreswere long (3m) and one was short (1m). CH8803 core was longer one andthe sediments were composed of black to grayish white clay. CH8801 corewas longer, too, but the sediments were coarser than those of CH8803core (sand to silt). In this paper we report the results of paleomag­netic study and stable isotope analysis carried out for CH8803 core.

PALEOMAGNETIC STUDY

Ninty-nine sequential paleomagnetic samples were collected fromone side of replicated cores in 2.2X 2.2X 2.2 cm3 non magnetic polycar­bonate boxes. Natural remanent magnetization (NRM) of the samples weremeasured with a ScT cryogenic magnetometer. The majority part ofsamples has NRM intensities ranged from 10- 7 to 10- 6 Am2/kg. The restpart of samples has more intense NRMs (Fig. 1).

Twenty-seven pilot samples were subjected to a stepwise alternat­ing field (AF) cleaning, at levels of 3, 6, 9, 12, 15, 20, 25, 30, 35,40, 45, 50, 55 and 60 mT (Fig.2). At lower AF levels, directions of

Int. NRM •[Am 2/kgJ ... .. .

10-6

t-----t-----=-'O,..;-,rl...·.-.-t-----+----+_---i.. ....lilt,· -... .."..,.. ~ , ..,,~ "'......,.. -- • • ....."..••4IW'O

•2 3 [m]

Figure 1. NRM intensity in log scale as a function of depth in metermeasured from the top of the core tube.

38

Y. l

245( 121.4 em )

Y,l

280( 206.7 em )

VOl?

Figure 2. Typical orthogonal vectorcomponent diagrams for stepwise AFcleaning. Closed circles represent endpoint of remanence vector projected onto a plane perpendicular to core axis(X-Y plane). Open circles projected onto a vertical plane (X-Z plane).

225( 72.6 em I

remanent magnetization are con­siderably stable. At higher AFlevels, the directions are scat­tered. Stable components ofremanent magnetization are ob­tained between 3-6 to 9-30 mT AFlevels for each sample.

All the rest samples weresubjected to a stepwise AF clean­ing at levels of 3, 6, 9, 12, 15,20, 25 and 30 mT. Directionaldeviations between ~djacent

samples are fairly large. Run­ning mean curves of the direc­tions after AF cleaning below 12mT AF level seem to represent thesame variation pattern with eachother (Fig. 3(a». Above 12 mTlevel the variation patterns aredifferent from each other (Fig.3(b) ) • These deferences would beattributed to instability of eachsample's remanent magnetizationafter high AF levels' cleanings.Average direction for each samplewas calculated using remanentmagnetizations measured after AFcleanings ranged from 6 mT to 12mT (Fig. 3(c)).

>-----+----i-----+---+--___+_----::~[.J >--_-+__--i---__<--_+-+-~cl+----+----'3(IiJ

Dec.

a)NRM -12mT

'": j

Inc.

~30

lnt. lnt.

10-< 10-<

Dec.

Figure 3. Change in relativ~ declination, relative inclination and in­tensity after AF cleaning at levels of (a)O, 3, 6, 9 and 12mT; (b)15,20, 25 and 30mT, smoothed with a seven-point running mean, correspondingto a 15cm averaging interval. Declination and inclination axi-s aremarked every ten degrees.

39

o

MEAN DIRECTIONo (6mT-12mT>

o

Figure 4. Relativedeclination and inclina­tion as a function ofdepth. Mean directionare unit vectorialaverage for AF dataranged from GmT to 12mT .Open circles representrelative declinationvalues and closedcircles represent rela­tive inclination values.Solid lines denoteseven-point runningmean .

••

•••

o 0

0

000 00

000 0 0

0

0

0

0(J)

00

00

0 o.0

0 0

• o·• .0

••

o

o°rP

•

•

30

Inc.

Dec.

Average directions are still highly dispersed through the core.Sample cases had arranged unidirectionally through transportation fromsampling site to our laboratory and through storage at the laboratory.If samples had remagnetized between sampling and magnetic measurement,resultant viscous components must have the same effect on the remanentdirection. Scattered directions cannot be attributed to this sort ofremagnetization. This dispersed pattern would reflect paleogeomagneticsecular variation itself. The directions might have been scattered, ofcourse, by random magnetic noises acquired at and after deposition ofthe sediments, and/or by sampling and measurement errors. Some averag­ing technique such as sample mean and running mean can diminish suchrandom noises.

STABLE ISOTOPE

13C/12C and 180/16 0 ratios in CaC03 deposited from supersaturatedwater are depend on their ratios in the mother water and its tempera­ture. Standardized 13C/12C ratio (0 13C) and standardized 180/16 0 ratio(0 18 0) are good indicators of paleoenvironment.

The stable isotope analysis was performed on using the samesamples used for paleomagnetic measurement. Only even numbered sampleswere used for this analysis. The results of 0 13CPDB, 0 180SMOW and C02gas recovery rate are plotted in figure 4.

C02 gas recovery rates reflect the volume of CaC03 contained insediment. Variation of the recovery rates contrast with the NRM inten­sity variation. This fact supports the idea that the NRM intensityreflect the concentration of magnetic minerals.

On the basis of changes of o13C, 0 18 0 and C02 gas recovery rate,CH8803 core was divided into three sections.

First section ( I ) is correspond to depth level ranged from bottomof the core to 2 m. This section is characterized by rapid decrease ofo 18 0, increasing 0 13C and unstable recovery rate. Instability of the

40

Figure 5. (] 18 0 and (]13C profiles of totalC02 and C02 gas recoveryrate profiles. Theaverage curves (five­point running mean) arealso shown (solid line),CH8803 core was dividedinto three sections(dashed line).

3 [m]

de lta 16 0[%.)

••

14

t \. •12

de lta 13 C[%.J

..6

4

recovery rate[OJ,)

•..40 .

• ..20

2

ill II

recovery rate might reflect the disturbance of lake water volume causedby inflow of sediments and water, and heavy rain fall.

Second section (II) is correspond to depth level ranged from 2 mto 1.1 m. This section can be regarded as the period of stable environ­ment. There are slight increase in a 13C and slight decrease in a 18 0.During this epoch the environment around Ch'i-Lin-Ts'o would have beencontrolled under steady state.

Third section (ill) is correspond to depth level upper than 1.1 m.In this section variations of three variables agree with each other.Increasing a 13C and a 180 indicate that supply of light water (low a13C and a 18 0; i.e. rain) generally decreased and/or evaporation oflight water and degas of light C02 generally flourished in this period,though in short time inflow of water and rain fall increased and there­fore lake water was diluted isotopically (indicated by arrows in figure5). It may suggest the existence of the dry environment more lately inTibet.

(to be submitted to Earth Planet. Sci. Lett.)

41

PALEOINTENSITY AT THE 75,000 YEARS B.P.

Hideo SAKAIDepartment of Earth Sciences, Faculty of Science

Toyama University, Toyama 930

The paleointensity of the paleolithic age was obtained atthe Douara site (34°38.5'N, 38°27.5'E) in Syria. The orientedsamples were collected from the baked earths in the fireplace atthe Douara cave (Akazawa and Sakaguchi, 1987). The mean NRMdirection shows the Declination of 11.8° and Inclination of53.5°. The paleointensities were estimated by the Thellier'smethod. The results in Table 1 indicate that the geomagneticintesity was about 65% of the present. The age of this Douarasite was determined by three methods. The age by both C14 methodand TL method shows that this site is older than 50 thousandsyears B.P. Fission track age by Nishimura (1979) suggested theage of 75,000 years B.P.

Table 1. Results of the paleointensity experiments by theThellier's method.

Specimens with the same integral number were cut from the same block sample of baked earth.F: determined past geomagnetic intensity; Fb: standard error of intensity; Tl and T2: tem­perature interval where NRM-TRM relation is linear; N: the number of points in this tempera­ture interval; C.C: coefficient of correlation of the points.

SpecimenNO.

1.11.21.32.12.2,3.13.23.34.14.24.35.15.26.16.27.17.28.18.2

o 32060 380o 320

60 320undeterminedo 260o 380o 320o 430o 380o 430o 150

undeterminedo 150

undeterminedo 210o 210o 430o 320

N

6779784

4

96

C.C F" Fb("T) (I'T)

0.997 28.7 1.00.991 34.1 2.30.996 32.8 1.20.993 24.0 1.6

0.992 23.0 1.40.997 28.8 1.00.993 26.9 1.40.996 36.2 1.20.979 29.6 2.80.994 29.2 0.90.951 38.4 8.8

0.997 39.9 2.3

0.998 22.7 2.00.958 35.8 6.20.991 23.5 1.20.936 26.8 4.5

Averaged past~geomagneticintensityF=29.4±4.1 I'T

Data with N(>7) and C.C(>O.99) were used for the calculation.

Figure 1 shows the paleointensity obtained from the Douarasite and the previously summarized data by McElhinny andSenanayake (1986). The large intensity around 30 thousands B.P.is considered to be caused by the lake Mungo excursion (Barbettiand McElhinny, 1976). Figure 1 indicates, besides the largeintensity around Mungo event, the weak intensity is dominant from75,000 to 20,000 B.P. Barbetti and Flude (1979) calculated theeffect of the paleointensities on the radiocarbon age by the

42

method of Lingenfelter and Ramaty (1970). They suggested if thepaleointensity before 50,000 B.P. is as weak as that of 50,000B.P., the age between 50,000 and 20,000 B.P. estimated by C14method may be few thousands years younger than the absolute age.The low intensity at 75,000 years B.P. suggests this possibility.The preliminary data from the volcanic rocks in Hokuriku district(Ogawa and Sakai, in prep.) show that the paleointesity around120 thousands B.P. was similar to the present value, whichindicates the dominant low intensity has possibly existed fromthe age older than 75,000 years B.P.

+ McElhinny & Senannynkc (1982)OSaka!

0.8

~ 0.6

@:g 0.4

~\:Ill

oS0.2

b ++rn +Z + ++

~0

+ + +++ +0

~ -0.2

~ -0.4

[iJ-0.6

0

+

+

+

+

+++ +

+ +++++

++

+

20 40

Age(DP)

+

60 80rnlousnnds)

Figure 1. The paleointensity obtained from the Douara site andthe paleointensities summarized by McElhinny and Senanayake(1982). The age of Douara site was estimated by Nishimura (1979).

References

Akazawa, T. and Y. Sakaguchi (1987) Paleolithic site of theDouara cave and paleogeography of Palmyra basin in Syria,part IV: 1984 excavations (University of Tokyo Press), 166.

Barbetti, M. and K. Flude (1979) Nature, 279, 202.Barbetti, M. and M.W. McElhinny (1976) Philos. Trans. R. Soc.

Lond. A, 281, 515.Lingenfelter, R.E. and R. Ramaty (1970) Radiocarbon variations

and absolute chronology; ed. Olsson, LU. (Almquist andWi ks ell), 513.

McElhinny, M.W. and W.E. Senanayake (1982) J. Geomag. Geoelectr.,34, 39.

Nishimura, S. (979) Univ. Mus., Univ. of Tokyo, Bull., 16,235.

43

PALEOMAGNETIC STUDY ON MIYAKO-JIMA ISLAND IN THE SOUTH RYUKYU ARC

Masako MIKII and Yo-ichiro OTOFUJI2

1. The Graduate School of Science and Technology,Kobe University, Kobe 657, Japan

2. Department of Earth Sciences, Faculty of Science,Kobe University, Kobe 657, Japan

Paleomagnetic direction of Ishigaki-jima Island in the south Ryukyuarc shows that the area has undergone clockwise tectonic rotation since10 Ma (Miki et al., 1989). The paleomagnetic study were carried out onMiyako-jima Island north-east of Ishigaki-jima Island, in an attempt tocompare~the paleomagnetic directions of the two islands.

Samples were collected from the Shimajiri Group (Fig. 1), for whichthe age of about 4 Ma were reported (Kuramoto and Konishi, 1989). Thesamples consist of fine clay from 20 sites and tuff from one site. Three

It~t~t~r~ Shimajiri G.

t5 km

Fig.1 Map showing the distri bution of the Shimaj i ri Group on Miyako-jima Island. Solid circles are sampling localities.

44

Fig.2 Typical examples of the orthogonalprojection plots for NRM stability ex­aminations. a: demagnetization path for atuff sample. b: demagnetization path for aclay sample. Open (solid) symbols show themagnetic vectors projection on the verti­cal (horizontal) plane. Th demag = thermaldemagnetization. AF demag = alternatingfield demagnetization.

W(UP)

W(UP)

E(DOWN)

E(DOWN)

200

Th demag.

Th demag.

NAM

100 C>c

NAM

W(UP)

W(UP)

65

E(DOWN)

E(DOWN)

AF demag.

AF demag.

~SI---l--t--1--+-t--lI--iN

NAM

'30mT

'-----." 4 0

a

b

or four oriented large blocksamples were collected byhand sampling from each claysite. About ten 2.5 cm cubicspecimens were cut from eachblock sample. Specimens werecoated with acrylic fiber.Ten block samples were col­lected from the tuff site,and two or three 2. 5 cm core NAM 10;"T 20

specimens were cut from eachblock sample.

The stability ofremanent magnetization wasexamined through progressivedemagnetization of both al-ternating field and thermaltechnique. The orthogonaldemagnetization plot showswell defined single mag­netization component areresolved by both demag­netization methods (Fig.2).The component was taken bythe principal componentanalysis by Kirschvink(1980) .

Reliable paleomagneticdirections were obtainedfrom 12 sites (Fig.3). Bothnormal and reversed polaritywere observed. The meandirection after tilt correc­tion is D = -1.5 0

, I = 27.0°and a 95 = 12.5°. The direc­tion shows no deflectionfrom northward, contrastingwith the clockwise deflec­tion in the Eocene and 10 Mapaleomagnetic direction ofIshigaki-jima Island.

The geomorphologicaldata shows, that there are no such large fault as cut the Ryukyu arc be­tween Miyako-jima Island and Ishigaki-jima Island (Hamamoto et al.,1979). Miyako-jima Island and Ishigaki-jima Island appears to be con­tained in one rigid block. The paleomagnetic results indicate thatMiyako-jima Island has not rotated since 4 Ma. We concluded that 1)Miyako-jima Island has been subjected to the clockwise rotation together

45

N

Fig.3 Site mean paleomagneticdirections with 95 % confidencecircles from the ShimajiriGroup on Miyako-jima Island.Projections are equal area,solid (open) symbols on thelower (upper) hemisphere. Star:mean direction.

~MEAN0=-1.5°I = 27.0°

(X95 = 12.5°

Wf--------+----~-__l E

s

with Ishigaki-jima Island as a rigid block since 10 Ma, 2) the rotationof south Ryukyu arc finished before 4 Ma.

References

Hamamoto, F., M. Sakurai and M. Nagano (1979) Report of HydrographicResearches, 14, 1-38.

Kirschvink, J.L. (1980) Geophys. J. R. Astr. Soc., 62, 699-718.Kuramoto, Sand K. Konishi (1989) Tectonophysics, 163, 75-91.Miki, M., T. Matsuda and Y. Otofuji (1989) Tectonophysics, in press.

46

PALEOMAGNETIC STUDY ON THE CENTRAL RYUKYU ARC- KINEMATIC HISTORY OF THE RYUKYU ARC -

Masako MIKI1, Shinya KOND02 and Yo-ichiro OTOFUJI2

1. The Graduate School of Science and Technology,Kobe University, Kobe 657, Japan

2. Department of Earth Sciences, Faculty of Science,Kobe University, Kobe 657, Japan

NRM

NRM

600

W(UP)

E(DOWN)

Th. DEMAG.

-t--t--l--ll N

300

W(UP}

600

E(DOWN}

Th. DEMAG.

NRM

W(UP}

E(DOWN}

AF DEMAG.

10

5 mT

E(DOWN}

Fig.1 Typical examples of orthogonalprojection plots for progressivedemagnetization experiments. a:Lavaflows of the Aradake Formation; b:1avaflows of the Uegusukudake Formation.Th demag = thermal demagnetization.AF demag = alternating field demag­netization. Open (solid) symbols showthe magnetic vectors projection on thevertical (horizontal) plane.

Paleomagnetic and Geochronological study were carried out on Ter­tiary rocks from Okinawa-jima Island and Kume-jima Island of the centralRyukyu are, in an attempt to see the kinematic history of the Ryukyu arc.The south Ryukyu arc has beenrotated clockwisely since 10 Ma a W(UP}

(Miki et al.,1989). In thisstudy, we determined the relativetectonic movement of the centralRyukyu with respect to the southRyukyu arc.

More than 200 samples werecollected from 21 sites. Thesamples consist of dike rocks (3sites) and Miocene sedimentaryrocks (1 site) from Okinawa-jimaIsland, and lava flows of theAradake Formation (12 sites) and blava flows of the UegusukudakeFormation (5 sites) from Kume- AF DEMAG.

jima Island.The K-Ar whole rock dating

was attempt on lava flows fromKume~jima Island. The amount of S~I-r-r~l

radiometric argon was measuredusing the method of Nagao andItaya (1988). We obtained the ageof 17.0 ± 0.4 Ma and 17.9 ± 0.4Ma from the Aradake Formation,and the age of 2.2 ± 0.1 Ma fromthe Uegusukudake Formation.

Stability of remanent mag­netization was examined throughprogressive demagnetization ofboth alternating field and ther­mal technique. The stable hightemperature component was definedas a linear segment decaying

47

Fig.2 Declinations' of the paleomagnetic directions for the Ryukyu arc.(a) Direction of a dike of 11 Ma from Okinawa-jima Island; (b) meandirection of the 17 Ma Aradake Formation; (c) mean direction of the 2 MaUegusukudake Formation. (d) Mean direction for the Eocene volcanics; (e)direction of a dike of 10 Ma (Miki et al., 1989).

toward the orlgln on the orthogonal plot (Fig. 1). The high temperaturecomponents were taken by the principal component analysis by Kirschvink(1980).

Reliable paleomagnetic directions were obtained from fourteen sites;D=-9.6°, 1=48.5° from a dike rock with the age of 11 Ma (Daishi et al.,1982) on Okinawa- j ima Island, D=8. 5°, 1=39.7°, a 95 =9.8° from nine sitesof the Aradake Formation and D=-l°, 1=40.5°, a 95=33.6° from four sitesof the Uegusukudake Formation on Kume-jima Island. These directions arealmost same as the present axial dipole field direction.

These results indicate that the central part of the Ryukyu arc hasundergone little rotation or translation since 17 Ma. Comparison with thepaleomagnetic direction of the south Ryukyu arc (Fig. 2) suggests thatthe central Ryukyu arc has behaved as the different block from the southRyukyu arc since 10 Ma.

References

Daishi, M. and M. Hayashi (1982) Geological Studies of The RyukyuIslands, 6, 5-10.

Kirschvink, J.L. (1980) Geophys. J. R. Astr. Soc., 62, 699-718.Miki, M., T. Matsuda and Y. Otofuji (1989) Tectonophysics, in press.Nagao, K. and T. Itaya (1988) Mem. Geol. Soc. Japan, 29, 5-21.

48

FAST DRIFTING OF SOUTHWEST JAPANINFERRED FROM PALEOMAGNETISM AND K-Ar DATING

YO-ICHIRO OTOFUJI*, TETSUMARU ITAYA**AND

TAKAAKI MATSUDA***

* Department of Earth sciences, Faculty of Science,Kobe University, Kobe 657, Japan

** Hiruzen Research Institute Okayama Branch,Okayama University of Science, Okayama 700, Japan

*** Department of Geology, Himeji Institute of Technology,Himeji 671-22, Japan

100Ma

Ii' aOMa

I•

_~___,_-1'"-'-~--'---1~.8~1-1-.~y.

~WAI §!§;j

:~

, ..

20Ma--'

aoT1001

OMORI I15

Miocene volcanic rocks have been sampled from the San' indistrict in the central part of Southwest Japan, in an attemptto evaluate the drifting velocity of Southwest Japan. Twenty

nine localities havereliable data of bothpaleomagnetic directionand K-Ar dati ng. Adeclination value of40.6' is observed inthe Kawai Formatlon of16.1 ± 1. 4 Ma, whereasa northerly directionCD= 1. 8') i sin theOmori Formation of 14.3± 0.6 Ma. The MatsueFormation of 11. 3 ±0.3 Ma shows northerlydeclinations. Thesedata indicate thatSouthwest Japan rotatedclockwise 40' between16. 1 ± 1. 4 Ma and 14. 3± O. 6 Ma. Comparedwith the amount ofrotation of SouthwestJapan estimated on thebasis of the Cretaceouspaleomagnetic data(Otofuji and Matsuda,1987), more than 80 %of" the clockwise rotation of Southwest Japanoccurred later than16. 1 Ma (F i g . 1).

ROTATION

'0 jo_o_-,-_2-,-O_O_~_4,-cf_~_....J6rcf,--_---M-A-T-SU-E---<j------

t•

Fig. 1. Rotation with respect to eastern part of Eurasia ver-sus age for geologic unit in the San' In district of SouthwestJapan. The rotation error bars are the t:.R= sin- l <sin a95/cOS 0)) where I and a 95 are inclination and radius of 95 %confidence about the mean direction. The age error bars arethe 95 % confidence limit. Shaded rotation zone is amount ofclockwise rotation of Southwest Japan with respect to easternpart of Eurasia estimated on the basis of the Cretaceous <80­100 Ma) paleomagne t ic data COtofuJ I and Matsuda, 1987) ,

49

The large rotational motion of 40· has spanned as littleas 1. 8 ± 1. 5 Myr. The angular velocity of Southwest Japanabout the rotation pivot of 129·E, 34·N reached 22·/Myr atabout 15 Ma. We thus conclude that the eastern part of South­west Japan moved at a rate of 23 em/year. The high driftingvelocity implies that the low viscous asthenosphere of the or­der of 1017 .-.... 10 19 Poise prevailed beneath the area of theSouthwest Japan-Japan Sea system at about 15 Ma.

REFERENCESOtofuji, Y. and Matsuda, T. (1987) , Earth planet. Sci. Lett.,

85, 289.

<submitted to Earth Planet. Sci. Lett.)

50

PALEOMAGNETIC STUDY AND FISSION-TRACK DATINGIN YANAGAWA ANDTAKADATEAREA,NORTHEASTJAPAN

Hirokuni aDA", Masayuki TORU' and Akira HAYASHIDA"

'Department of Geology and Mineralogy, Kyoto University, Kyoto 606, Japan"Laboratory of Earth Sciences, Doshisha University, Kyoto 606, Japan

Paleomagnetic study and fission track dating were carried out on the Miocenesediments and volcanic rocks in the Yanagawa and the Takadate areas, Northeast Japan.These areas are situated in the northern margin of the Abukuma massif which mainlyconsists of the Mesozoic granitic rocks. The Abukuma massif is bordered by two largetectonic faults. One is the Futaba fault on the eastern margin and the other is theTanakura fault on the southwestern margin (Fig. 1).

In these areas, basalt, andesite and rhyolite lava flows and pyroclastic layers

unconformably overlie the granitic basement and there are some intrusive rocks (Fig. 2).The Ryozen volcanic rocks are widely distributed in the Yanagawa area. Three K-Ardates were reported for these rocks as 14.1, 15.0, and 21.7 Ma (Kimura, 1988). In theTakadate area, volcanic rocks of the Takadate Formation are distributed. K-Ar agesobtained from these rocks are 12.6, 15.2, 20.7, and 220 Ma (Uto et aI., 1989).

The volcanic rocks are covered by the sedimentary rocks which contain largeamount of volcanic material. In the Yanagawa area, the Yanagawa Formation cover theRyozen volcanic rocks. The Yanagawa Formation consists of tuffaceous sands and siltThe sediments of the Yanagawa Formation is subdivided into three members (Suzukiand Wako, 1987). The lower member is the Hirosegawa Member which consists ofcoarse sand stone with many shell fossils. The middle part of the Yanagawa Formationis called the Isazawa Member which bears planktonic foraminifera and calcareousnannofossils. The upper part, the Ubagafutokoro Member, consists of pumiceous siltand sand stone. The Hirosegawa Member is correlated to Blow's N8 zone and the IsazawaMember to N9-NlO by Suzuki and Wako (1987). In Takadate area the MoniwaFormation which mainly composed of conglomerate covers the Takadate Formationunconformably. The Moniwa Formation bears N8 planktonic foraminifera fossil. TheMoniwa Formation is covered with the Hatatate Formation. The Hatatate Formationmainly consists of tuffaceous fossiliferous silt (Kitamura et aI., 1986). The lower mostpart of the Hatatate Formation is correlated to N9 and the middle part to N16 (ada andSakai, 1977).

We collected about ten hand-samples for paleomagnetic study from each site.

51

.. --Skm

RyozmFormation

Yanagawa area J~J '~!lY~,,,,. .':';';':';';~7,,~~~I.:!f';q

X}'}8·!5~

:~~}~~i:'

iI.RZ.ll

Takadate area

IOkm

~!tfoniK"a~ Formation

N

t

•-- Hala/ate

Fom,al;on

~_T~:~~{;on

~ TS;::::a~fono Grtmite

Fig. 1 Sample sites of the Yanagawa area (right) and the Takadate area (left). Base map

is from Suzuki and Wako (1987) and Kitamura et ai. (1986).

/':,Ryozcn Formation

* microfossilsA wrK-Arage6. F-Tage(Tllis study)* sampling horizonr.

*'* •MoniwaFormat"~n

Takadate Formation

Tsukinoki.Formation •

••... :

HatadateFormation:c\

.4•••••••••••••/':, .

A •

Kellashi)'amaAndesite

l'tznagawll

Formation

•r-------l.* ••••... :

i'j~l

15Ma N9

N8

N?

20Ma

/Oda,1986jGranite Granite

lllllagaH'll areaTakadate area

Fig. 2 Geologic columnar sections of the studied areas. Asterisks indicate sample sites.Star represents datum of the biostratigraphic control by microfossils (Suzuki and Wako,

1987; Oda and Sakai, 1978). Open and Solid triangles denote fission- track dates by the

present authors and whole rock K-Ar dates (Kimura, 1988; Uto et aI., 1989).

52

Samples for fission-track dating were collected to determine the ages of acidic volcanicrocks from three sites. Natural remanent magnetizations are measured using a cryogenicmagnetometer (ScT C-1l2) and a spinner magnetometer (Schonstedt SSM-1A). Bothalternating field demagnetization (AFD) and thermal demagnetization (ThD) wereperformed progressively on two or three pilot specimens from each site. We could obtainstable remanent magnetizations from the volcanic rocks. Some of the sediments alsoyielded stable components. The stability of the remanent magnetizations are confirmedon the orthogonal projections diagrams (Fig. 3). Tilt corrections are carried out only onthe magnetic directions from the sediments. We rejected some sites which showedinstability against progressive demagnetization process. We selected sites that gavestable magnetic components and whose AFD and ThD results agree well with each other.

Fission-track dating was carried out by external detector method (ETD) onzircon crystals using internal surface and calibrated by zeta-value (Table 1).

Paleomagnetic directions obtained from volcanic rocks indicate both clockwiseand counter-clockwise deflection as shown in Fig. 4. The overlying sedimentary rocks,however, exclusively show clockwise deflected directions after untilting (Fig. 4). We thinkthat the remanence of the sediments are reliable because of their stable and strongmagnetization. The age of the clockwise deflected sediments are assumed to be N8 in

terms of calcareous microfossils. Most of the reliable mean direction point clockwisefrom the present axial dipole field throughout the studied area except some sites fromthe Ryozen volcanic rocks (Fig. 4). This apparent inconsistency may be attributed tounsuccessful tilt correction for the volcanic rocks. However most of the remanence ofthe sedimentary rocks are of viscous nature. This fact may indicate another possibility toexplain the clockwise deflection due to the viscous magnetization.

Otofuji et al. (1985) reported that Northeast Japan had rotatedcounter-clockwise about 50· between 20 Ma to 12 Ma as a result of the opening of theJapan Sea. Taking account the ages (N8) and the clockwise directions from the studiedarea, the areas rotated clockwise relative to the main part of the Northeast Japan. Weinterpreted this inconstant rotation to the fault movement along the Futaba fault whosemaine tectonic phase has been estimated to be middle Cretaceous (Tsuneishi, 1978). If

the Futaba fault was reactivated as a right lateral strike slip fault, the Yanagawa andTakadate areas could be rotated clockwise through mechanism called "ball bearing" (Beck,1980) as shown in Fig. 5. Tsuneishi (1978) suggested that there were four tectonic stagesin the movement of the Futaba Fault His second stage (early Miocene) of the faultmovement possibly brought about the block rotation of the studied areas. The secondstage movement is characterized by the normal fault caused by the EW-trending tensionalforces. However he could not find any line of evidence to indicate large-scale lateralmotion of the Futaba Fault during middle Miocene. Otofuji et al. (1985) reported a

53

(a) AZ·30 : PThD (dacite dike) (b) AZ·30 : PAFD

.160'C

Olv, ... 5.0 x 10-4Am~

lomT

DtY.... S.OX10",Am1

EOn

(c) RZ-24 : PThD (tuffaceous siit)

WUp

-+--:-1'~-~---+--~--~-N6OO'C~ .

320'~ ~

ow. =: 5.0 X10'Am2

120'C

2O'CEOn

(d) AZ-24: PAFD

WOp

DIv. =5.0 x 1O-'Am~

EOn

EOn

'mT

omT

Fig. 3 Typical examples of progressive thermal demagnetization and progressive

alternating field demagnetization, projected on the vector orthogonal diagrams. (a) and (b)

show thermal and alternating field demagnetizations from the volcanic rocks, respectively.

(c) and (d) show thermal and alternating field demagnetizations from the sedimentaryrocks, respectively.

Sample N spontaneous indused dosimeter glass age(l (1) P(x 2 )

name track track track

density density density(xIOScm-3 ) (xIOScm- 3 ) (xI0'cm- 3 ) (Ha) (X)

OHm 10 1.17 1.82 14.84 16.2±0.7 88

FcrZR6 6 5.72 5.50 14.84 26.3±1.3 2RZ-34 8 3.51 2.67 8.82 19.8±0.9 9RHO 7 2.61 2.10 8.82 18.7±1.1 ITK-3 3 2.83 3.85 8.82 13.8± 1.0 12

Table 1. BM4II and FCTZR6 are age standard samples. N is number of ziroon grains

measured. NBS-SRM612 is used for dosimeter glass. P(KaF) is probability of obtaining

the observed value. We used 342.1 as zeta-value(Tagami, 1987).

54

<",-N" > '7","""b'~lIirosegaH'a member

<N8> +

N

Ryuzen Formatioll

N

/latadale Formatioll

(t.I01riH'a Formation

+

N

Takadate Formatioll

<l5Artl-22Ma>~+

Yal/agall'a area

o+

7'akadate area

Fig. 4 Site-mean directions are illustrated on equal area projections. Directions from thesedimentary sites are untilted. Paleomagnetic directions are arranged from bottom to topin terms of their geologic age; bottom (15 - 22 Ma), middle (N8), and top (N9 - Nll).

Right side of the figure indicate the data from the Takadate area, and left from the

Yanagawa area.

• This study (sediments)III Simp/ifiedfrom Otofuji et al.(1985)

Fig. 5 "Ball-bearing" rotation of the crustal block. (a) Model showing "ball-bearing"rotation of a small block sandwicthed between two large fault-bounded blocks in a sense of

Beck (1976). (b) Right lateral motion along the Futaba fault can explain clod.wise

rotation of the studied areas. Solid circles show the paleomagnetic directions from the

sediments of the present study. Solid squares indicate paleomagnetic directions from

Northeast Japan simplified from Otofuji et al. (1985).

55

couple of stable remanent magnetizations of clockwise deflected directions from the

western Asahi mountain area. They explained those anomalous direction to the movement

of the Tanakura fault which was activated by the opening of the Japan Sea. The

anomalous paleomagnetic directions may reflect local-scale tectonics which cannot be

detected by the previous geological studies. Detailed paleomagnetic study will reveal

actual process of the crustal movement accompanied with the large-scale tectonic

movement such as the opening of the Japan Sea.

References

Beck M.E. (1976): Am. Jour. Sci., 276, 694-712

Kimura,K. (1988): Rep. Tech. Res. Center, 15, 14-17.

Kitamura,N., T.Ishii, ASangawa, H.Nakagawa (1986) : Geology of the Sendai district,

Geol. Surv. Japan, 134p

Oda,M., T.sakai (1977): Prof. K.Fujioka Memorial Volume, Univ. Touhoku, 441-456.

Oda,M. (1986): Prof. N.Kitamura Memorial Volume, Univ. Touhoku, 297- 312

Otofuji,Y., T.Matsuda, and S.Nohda (1985): Earth Planet Sci. Lett, 75,265-277.

Suzuki,K., R.Wako (1987): Sci. Rep., Univ. Fukushima, Fac. Education, 40,33-48

Tagami,T. (1987): Nucl. Tracks Radiat Meas., 13,127-130.

Tsuneishi,Y. (1978): Bull. Earthq. Res. Inst, Univ. Tokyo, 53, 173-242.

Uto,K., K.Shibata and S.Uchiumi (1989): Jour. Geol. Soc. Japan, 95, 865-872.

56

PRELIMINARY RESULTS FROM PALEOMAGNETISM ON APPARENT POLAR WANDER PATHFOR THE SOUTH CHINA BLOCK

Yasuhisa ADACHII), Hayao MORINAGA1), Yu Yan LIU2),Guo Zhu FANG2) and Katsumi YASKAWA3)

1) The Graduate School of Science and Technology, Kobe University1-1, Rokkodai-cho, Nada-ku, Kobe 657, Japan2) China University of Geosciences (WUHAN)

Yujiashan, Wuhan, Hubei, People's republic of China3) Department of Earth Sciences, Faculty of Science, Kobe University,

1-1, Rokkodai-cho, Nada-ku, Kobe 657, Japan

China is composed of several distinct continental fragments separatedby accretionary fold belts (Zhang et al., 1984). Paleomagnetic study hasbeen performed on sedimentary rocks from the Quaternary to the Precambrianformations to establish an apparent polar wander (APW) path for SouthChina block. At the present, paleomagnetic data are few (McElhinny etal., 1981; Chan et al., 1984; Lin et al., 1985; Kent et al., 1986), spe­cially for Paleozoic and Proterozoic, to establish the APW path for theSouth China block.

Oriented hand samples were collected from Wuchang (30.2° N, 114.3° E)and Jingshan (31.2°N, 113.1°E) counties in Hubei province (Fig.1). Thesampling sites were distributed in formations of all the periods or erasfrom the Quaternary to the Middle Proterozoic respectively (84 samplesfrom 17 sites)(Table 1). The lithofacies of the samples are mainly lime­stones and sandstones, only the Quaternary samples are unconsolidated claysediments.

Remanent magnetizations of all specimens were measured with supercon­ducting quantum interference device (SQUID). Natural remanent magnetiza­tion (NRM) of most specimens was stable and the intensities distributed

~ Precambrian Block~~~~\G

[]]] Microcontinent 25'Ni \~I~~~~OFoldBe~.D:3 Major Non-Terminal Suture

\

Fi~.l Sketc.h map. of eastern Asia (traced from Liou et al., 1989) showingmaJor tectonic. units and paleomagnetic sampling localities (star symbols).SCB, South Chllla block; NCB, North China block; TRB t Tarim block; QLF,Qinling fold belt; SCF, South China fold belt.

57

(a)N(UP)

(b)N(UP)

S(DOWN)S(DOWN)NRM

W I-}-+-I--+---I--+-I--E W1----t--==l!!::f===l""'-----l-...5-90-+o,-c E

Fig.2 Vector plots of a), alternating magnetic field (AF) demagnetizationmethod and b), thermal (TH) demagnetization treatment of samples (MiddleProterozoic dolomite) from Jingshan area. Open circles plotted on verti­cal planes and filled circles plotted on horizontal planes in geographiccoordinates.

from 8.49X lO-2A/m (Quaternary sediment) to 1.48X lO-4A/m (LateProterozoic sandy shale). Each characteristic component was obtainedthrough thermal demagnetization treatment rather than alternating magneticfield demagnetization method (Fig.2). All the specimens were demagnetized

Table 1 Characteristic site-mean directions for Quaternary to MiddleProterozoic rocks in Wuchang and Jingshan of the South China block

I In situ Tilt corrected VGPsEra I PericxI Site Sa Sp

I Dec. Inc. k a" Dec. Inc. k a.5 lat. (' N) Long.(' E)

I Quaternary 1~12 12 12 -2.2 47.3 ID.O 15.2 -2.2 47.3 ID.O 15.2 86.7 328.4Cenoloic I Tertiary 108 5 7 19.7 63.3 32.8 13.6 23.6 71.1 33.0 13.5 60.5 140.4

I Cretaceous ID9 4 6 -167.3 -34.6 20.2 21.0 -168.5 -41.0 19.9 21.1 77.2 237.4Jurassic 019 5 10 4. I 47.8 11.3 20.9 1.5 -15.2 2.7 50.7

Mesozoic Triassic ID5 5 8 -1.6 57.6 13.3 17.2 -84.1 0.8 2.9 42.8--TPerm i~n 106 5 9 -3.9 42.0 60.6 7.2 -96.9 -6.8 24.7 11.4206 4 4 -3.7 54.6 55.2 16.8 10.9 II. I 64.6 15.5ICarbnniferous 115 4 7 -5.5 48.0 85.5 7.3 -ID4.9 6.5 89.2 6.5

Oevonian ID7 5 5 11.9 36.4 48.8 13.3 -ID3.8 -22.8 48.5 13.3 17.8 199.8I Si lurian 103 4 7 8.9 56.8 92. I 7.0 -100.2 48.0 72.7 7.9II Ordovician 102 5 7 9.2 ,49.1 81.0 7.5 -75. I 55.0 58.2 8.9

late Cambrian 101 4 6 46.6 51.8 20.6 20.8 -134.9 67.3 38.5 15.0 0.6 86.1Paleozoic i early Cambrian 112 5 8 -2.7 24.3 5.7 27.8 -43.2 30.9 5.3 30.9 48.2 13.0

i 113 4 8 11.6 55.5 121.3 5.5 -69.2 75.5 51.7 8.5

! late 111 4 6 -174.5 -33.6 122.7 11.2 135.3 -6.6 160.8 9.8 39.6 358.7

Proterozoic I211 5 7 13.7 46.6 131.3 5.9 27.8 42.1 106.0 6.5

middle 110 4 6 -71.4 15.5 26.5 15.1 -60.0 10.7 17.3 18.9 28.3 11.5

Sa is the number of samples per site, from which Sp, the number ofspecimens were measured. k is Fisher precision parameter of site-meandirection. a 95 is radius of cone of 95% confidence on within-site andoverall means. VGPs are virtual geomagnetic poles calculated for si te­means after tilting corrections.

58

N

N

d.N

N

c.N

b.N

N

a.

Fig.3 Site-mean characteristic directions before tilting corrections.Filled and open circles on lower and upper hemisphere, respectively, andellipses are 95% confidence circles of equal-area projections. Asterisksymbol is the direction of the geocentric dipole field for samplinglocality. a, Quaternary (Q); b, Tertiary (E); c, Cretaceous (K): d,Devonian (D); e, Late Cambria.n (Cm): f, Early Cambrian (Z); g, LateProterozoic (Pt3): h, Middle Proterozoic (Pt2).

through progressive thermal treatment and the characteristic component ofremanent magnetization for each site was separated using multivariatetechnique of Kirschvink (1980). The site-mean paleomagnetic directionsfor thermally demagnetized results are shown in Table 1. The high tem­perature component was adopted for the site for rocks showing the charac­teristic multi-component because of little possibility of secondary vis­cous magnetization. The characteristic component for each site was ac­cepted as reliable provided the following criteria were satisfied: aremanent magnetization is stable with respect to progressive thermaldemagnetization and a site-mean direction before tilting correction isdifferent from the direction of the geocentric dipole field, suggestingthat the direction of remanent magnetization is not attributed at least torecent secondary magnetization.

Eight sites were found to have a reliable primary magnetic componentthrough thermal demagnetization and selection using above mentionedcriteria. Paleomagnetic directions of these sites before tilting correc­tionare plotted with associated circles 95% confidence in Fig.3. Thesesites are from the formations of Quaternary (Q), Tertiary (E), Cretaceous(K), Devonian (D), Late Cambrian (Cm), Early Cambrian (Z), Late (Pt3) andMiddle Proterozoic (Ptz). It is very significant that paleomagnetic datafor Paleozoic and Proterozoic were successfully obtained from presentstudy.

Virtual geomagnetic poles (VGPs) calculated from the data aftertiling correction were shown in Fig.4. These pole positions were comparedwi th those previously reported for the South China block. Kent et al.(1986) reported the Cretaceous paleomagnetic pole (80.8°N, 296.8°E, a 95

=7.r) from western Sichuan (26.5°N, 102.~E) and another one (76.3°N,lI2.6°E, a 95=10.3°) from Nanjing area (32°N, 119°Ej. These paleomagneticpoles were shown in Fig.4 by triangular symbols. Our Cretaceous poleposition is located between the two poles of Kent et al. (1986) and is notsignificantly different at the 95% confidence level.

59

180 0

em ~_--.--__

90 0 W t--------

Fig.4 VGPs for the Quaternary to Middle Proterozoic rocks with associatedcircle of 95% confidence. Poles shown by triangular symbols are reported~y Kent et al. (1986), N, Nanjing area; S, Western Sichuan. A dotted lineIS APW pat.h for the South China block demonstrated by Lin et al. (1985).Ter, T~rtlary; ~2, Upper Cretaceous; Kl, Lower Cretaceous; J3, UpperJurass.lc; J2, Mlddle Jurassic; Tr, Triassic; P, Permian; C3, UpperCarbonlferous; Cl, Lower Carboniferous; Cm, Cambrian.

Lin et al. (1985) demonstrated the Phanerozoic polar wander path forthe South China block from paleomagnetic of several formations in Zhejing,Guizhou, Yunnan and Hubei provinces. The polar wander curve was describedin Fig.4 by a dotted line. The paleomagnetic pole for Cretaceous rocks weobtained for Hubei province (77.2°N, 237.4°, a 95=21.1°) agrees well withlower Cretaceous one (76.2°N, 225.7°, a 95=4.8°) of Lin et al. (1985). Ashape of APW path since Devonian from present study is similar to that ofLinet al, (1985). The inconsistency on the Cambrian pole position mayhave been caused by that Jingshan area had been subjected to the tectonicdeformation by Qinling orogenic movement because Jingshan is close to theQinling orogenic belt.

REFERENCESChan, L.S., C.Y.Wang and X.Y.Wu (1984) Geophys.Res.Lett., 11, No.11, 1157.Kent, D.V .• G.Xu, K.Huang, W.Y.Zhang and N.D.Opdyke (1986) Earth

Planet.Sci.Lett., 79, 179.Kirschvink, J.L. (1980) Geophys.J.R.astr.Soc., 62, 699.Liou, J.G .• X;Wang and R.G.Coleman (1989) Tectonics, 8, No.3, 609.Lin, J.L., M.Fuller and W.Y.Zhang (1985) Nature, 313, No.7, 444.McElhinny, M.W., B.J.J.Embleton, X.H.Ma and Z.K.Zhang (1981) Nature, 293,

No.17, 212.Zhang, Z.M., J.G.Liou and R.G.Coleman (1984) Bull. Geol.Soc.Am. , 95, 295.

(To be submitted to Nature.)

60

NATURAL REMANENT MAGNETIZATION OF SOME ROCKS FROM SURTHERN SRI LANKA

Minoru FUNAKl1, Masaru YOSHIDA2 and P.W. VITANAGE3

1: National Institute of Polar Research, 9-10, Kaga 1-chome Itabashi-ku,Tokyo 173, Japan

2: Department of Geosciences, Osaka City UniversitY,3-138 sugimoto 3-chome,Sugiyoshi-ku, Osaka 558, Japan

3: Department of Geology, University of Peradeniya, Peradeniya, Sri Lanka

1. Introduction

Recently geological and geochronological know ledges of Sri Lanka havebeen accumurated in focused on reconstruction with East Antarctica. Thegeneral reconstruction model has been proposed that Sri Lanka was situated inGondwana in the offing of Lutzow-Hoim Bay connected with the east GunnersBank in Enderby Land, East Antarctica (e.g. Collerson and Sheraton, 1986:Yoshida and Funaki, 1987). Structural, petrological and metamorphic gradeare similar between the Highland Group of Sri Lanka and the granulite faciesportion of Lutzow-Holm Complex and between the eastern Vijayan Complex of SriLanka and the Yamato Belgica Complex of eastern Queen Maud Land (Yoshida andFunaki, 1987). This model is also supported by the geochronologicalevidences (e.g. Grew and Manton, 1979).

However, very poor paleomagnetic study has been done for Sri Lanka up topresent. Funaki et al. (1989) carried out paleomagnetic reconnaissance ofPrecambr ian and Jurass ic rocks 0 f Sri Lanka us ing the samp les co 11 ected forgeological studies. The results indicated that the dominant NRM directionsof the Highland Group form two clusters at 1=61.2°, 0=260.4°, a 95=5.8°(cluster A) and 1=68.7°, 0=349.0° and a 95=6.9°(cluster B). Many samples ofthe Vijayan Complex showed relative low lnclination without clear clusteraround the present geomagnetic field direction of Sri Lanka. Jurassicdolerite dyke rocks showed the mean NRM direction of 1=24.6°, 0=67.5° anda95=24.6° (cluster C), although number of sample was only 2.

The VGP positions obtained from the cluster A (latitude (Lat)=2.3°N,longitude (Lon)=34.1°E) and cluster C (Lat=24.00N, Lon=159.5°E) wereconsistent with those of Cambro-Ordovician and Jurassic VGPs from EastAntarctica after rotation of Sri Lanka based on the model proposed by Barronet al., 1978.

We obtained a total of 95 paleomagnetic samples from southern Sri Lanka.The rock types are granite (Tonigala granite) and granitic rock from Tonigalaregion, dolerite, biotite gneiss and pegmatite from Gallodai region, granite(pink granite) and migmatite from Kandy region, charnockite from Mahiyangaranregion and gneissose granite and hornblende gneiss from Ambarangoda region.The samples of biotite gneiss were collected systematically taking distanceinto consideration of the dolerite dike at Gallodai region.

2. Basic magnetic properties

Representative 3 samples from each formation were selected for AFdemagnetization test up to 50mT. The stable NRM components were recognizedin Tonigala granite, pink granite, Gallodai dolerite, migmatite, gneissosegranite, pegmatite and biotite gneiss. The samples of hornblende gneiss haveeither stable NRM or unstable one. However only unstable NRM was recognizedfor charnockite and granitic rock from Tonigala region. Figure 1 showsZjiderveld projection of Gallodai dolerite, having a larger soft magneticcomponent, which is demagnetized completely up to 20mT, associated with thehard NRM component. The optimum demagnetized field intensities were decided

61

UN Gallodai dolerite1

o1

Thermal demag.Gallodal dolerite

oL-_-.--_-.-_--r-_-:'"!:-=-_.....---:~

o 200 400Temperature (OC)

Fig. 2Thermal demagnetization of

Gallodai dolerite.

50W E-1 50 1

30

-1

• horlz. 0

• vert

OS

Fig. 1AF demagnetization ofGallodai dolerite.

to 30mT for every sample, except 35mT for pink granite, based on the resul tsof the ljiderveld projections.

Thermal demagnetization test was carried out for the samples to havestable NRM components in air from room temperature to 630·C at intervals of50·C. The samples were supplied after being AF demagnetized to the optimumfield. Unblocking temperatures (TBs) of NRM were observed between 530· and580·C for Tonigala and pink granites, although demagnetization curves werezigzag compared with those of the AF demagnetization. The unstablemagnetization is estimated due to oxidation of magnetic minerals and breakingoff of small parts of the samples during heat treatments. A clearly definedTBs of NRM were obtained at 580·C and 330·C for Gallodai dolerite, as shownin Fig. 2. They are the TBs of the hard NRM component, because the samplewas already AF demagnetized to 30mT. Significant directional change of NRMwas not observed before and after the TB at 330·C. The TBs of NRM for gneissrocks and migmatite were distributed between 330· to 580·C, although it isoccasionally different TBs among same formations.

Thermomagnetic (Js-T) £urves of the 1st and the 2nd run cycles in Fig. 3were obtained·for the samples of Tonigala granite, pink granite and Gallodaidolerite from room temperature to 650·C by a magnetic balance under 0.4Texternal magnetic field in 10- 2pa atmosphere. The Js-T curves of Tonigalagranite is completely reversible with Curie point at 580·C indicating singlephase of almost pure magnetite. By the microscopical observation, magnetitegrains smaller than 200,um in diameter were observed in the sample. That ofpink granite is irreversible in the 1st run cycle; magnetization increasesafter the cooling maintaining same Curie point. This phenomenon suggeststhat small amount of magnetite was produced by the heating. In this samplemagnetite grains smaller than 250,um in diameter with ilmenite exolutionswere observed by the microscope. Very small amount of hematite was observedalong the grain boundary and cracks of the magnetite grains. The increasedmagnetization after the 1st run cycle is caused by reduction of thishematite. The samples of Gallodai dolerite showed irreversible Js-T Curveshaving Curie point at 575·C in the 1st run cycle. After the cycle themagnetization decreased about 83% compared with original one. The 2nd run is

62

Js - T curves of graniteand dolerite

co:;:CON:;:Q)CQ)CO:E"0Q)

.~iVE..oz

Tonlgalagranite

1st run2nd run

H=O.4T

Fig. 3.Thermomagnetic curves ofTonigala granite. pinkgranite and Gallodaidolerite. solid lines:the 1st run cycle,dotted line: the 2nd runcycle.

o 100 200 300 400 500 600 700 "C

Temperature

reversible and consistent with the 1st run cooling curve, maintaining sameCurie point. Microscopical observation suggested that the magnetic grainssmaller than lOO,um in diameter were heavily oXidized; maghemite and/ortitanomaghemite veins were spread into the magnetite grains.

;]. NRM direction

Every sample having stable NRM components was AF demagnetized by ;]steps; the respective optimum field and both of lower and higher 5mT thant.hat field. When a 95 showed the minimum value, mean NRM directions wereadopted for representative NRM direction of its formation. Reasonably goodclusters were obtained from Tonigala granite, pink granite and Gallodaidolerite. The mean NRM intensity (R), inclination (1), declination (0).precision (K) and a 95 are listed in Table 1 and NRM directions with a 95values are illustrated in Fig. 4. The NRM directions of hornblende gneIssand gneissose granite clustered unclearlY around the present geomagneticfield direction at present Sri Lanka, probablY resulting VRM. Biotite gneiss

63

NRM distributions after AF demag.to 30 or 35mT

o

30~

60~ \

2701----+-- fj] E)

180

Fig. 4The mean NRM directions and a 95values of (1) Tonigala granite,(2) pink granite and (3) Gallodaidolerite.

and pegmatite within 10m from the dolerite dyke showed almost parallel NRMdirection to that of dolerite dyke. It may suggest that biotite gneiss wasremagnetized by heating of the dyke intrusion. However, the NRM directionsof migmatite scattered widely through the both hemisphere althoughindividual samples have stable NRM components. '

4. Discuss ion

Tonigala granite has almost pure magnetite grains estimated from theJs-T curves. Since its NRM is very stable against AF and thermaldemagnetization, the NRM is believable paleomagnetically. The NRM of pinkgranite is also stable, but a part of the magnetite grains were oxidized tohematite. Hematite may be produced by the weathering in present judging fromits formation on the garins. As the amount of hematite is very slallcompared with magnetite, the original NRM may not be so disturbed by thehematite magnetization. On the other hand, a part of the NRM of Gallodaidolerite is carried by maghemite and/or titanomaghemite, associated with themagnetization resulting magnetiet. Biotite gneiss remagnetized evidently bythe dolerite intrusion showed the NRM direction toward that of Gallodaidolerite. It indicates that the NRM direction of Gallodai dolerite did notbe disturbed by the formation of maghemite and/or titanomaghemite. Fromthese estimations the NRM of Tonigala granite, pink granite and Gallodaidolerite can be believed.

Geochronological ages have been obtained from Tonigala granite (forinstance 986± 28ma by Rb/St of total rock (Crawford and Oliver, 1969) and558±14ma by U/Pb of zircon (Holzl and Kohler, 1987». The ages may indicatethe times intruded at middle Proterozoic and metamorphosed at Cambrianrespectively. A Cambrian age (580±7ma; U/Pb in zircon) has been reportedfrom a similar rock with pink granite around Kandy region (Kroner et al.,1987). Many data from 460 to 520ma (late Cambrian to middle Ordovician) byRb/Sr age have been reported from whole Sri Lanka. Since the age determinedby L/Pb method shows older age than that of Rb/Sr one generally, it can be

64

* after rotation: rotation Lat=5.3°S, Lon=23.8°E and w=-100.5

understood that wide areas of Sri Lanka were metamorphosed at late Cambrianto middle Ordovician. These areas might be magnetized or remagnetized attha t per iod.

The NRM directions of Tonigala and pink granites were consistent eachother taking their a95 values into consideration. In the paleomagneticreconnaissance of Sri Lanka (Funaki et al., 1989). the NRM directions of manygranites and gneisses showed (Cluster A) toward the same directions to thesegranites in this study. Therefore it seems that they were acquired NRM atalmost same time. However, as the age of Tonigala granite (Halzl andKohler, 1987) was determined directly using the samples which are collectedfrom a same outcrop for our sampling site, the paleomagnetic data of Tonigalagranite is adopted for the representative data of late Cambrian to middleOrdovician of Sri Lanka in this study.

Age of Gallodai dolerite has been reported as 152.6±7.6 and 143.3±7.2ma by K/Ar of total rock by Yoshida et al., 1989. It indicated that thedolerite was magnetized at the latest Jurassic or the earliest Triassic. TheNRM dire~tion 1=33.6°, 0=88.3° and a 95=6.4° is essentially consistent withthe preVIOUS result of GallodlH dolente 0=24.6°, D=67.5° and a95=21.7°).

Funaki and Wasilewski (1986) reported a VGP position of hornblendegneiss, amphibolite and granite from Ongul Island in Lutzow-Holm Bay asLat=20.2°S. Lon=20.7°E and a 95=4.5°. These rocks were estimated to beremagnetized or intruded at Cambro-Ordovician. On the other hand, manyJurassic VGP positions have been reported from Ferrar dolerite along theTransantarctic Mountains. One of them is Lat=45.3°S, Lon=152.00W anda 95=2.4° for Wright Valley (Funaki, 1983). Sri Lanka has been estimated tobe a Gondwana fragment connected with Lutzow-Holm Bay (e.g. Barron et al.,1978). Therefore the reconstruction of Sri Lanka and Lutzow-Holm Bay isavailable using the Cambrian to Ordovician VGP positions from Tonigalagranite and Ongul Island, and Jurassic ones from Gallodai dolerite and Ferrardolerite.

The VGP positions calculated from Tonigala and pink granites andGallodai dolerite were rotated with respect to East Antarctica referred arotation point Lat=5.3°S Lon=23.8°E and an angle (w)=-100.5°(counterclockwise). The rotation point and w were determined by fittingVGPs of Tonigala granite and Ongul Island and those of Gallodai dolerite andFerrar dolerite. The latitude and longitude of the VGPs. after the rotationare listed in Table 1. When Sri Lanka is rotated according to that rotation,it situates at offing of eastern Queen Maud Land. This result supports thehypothesis that Sri Lanka connected to the east Gunners Bank in L'litzow-HolmBay taking their a 95 value consideration. Figure 5 shows a plausiblereconstruction models of Lutzow-Holm Bay and Sri Lanka based on thedeclination of NRM and its 95% probability for Tonigala granite and the

65

ENDERBY LAND

I777l CElIOZOIC COVER IIiClUOlliGlLLLIlCE SIIEETI~ AWIIIUOllT£ FACiES HRMIlI~WlllllRUlO L1t1ESp"~';;\;1 GRAIlULIT( FACIES T£RRAIfl"·0·.·- Willi TRE"O lI"ES

km ~ HIHGES OF w\JOR FOLDS

,--~_200 / BOU"OARY BETWWI GEOlOGIC-" lIlHTS

Fig. 5A plausible reconstruction modle

for Sri Lanka and LUtzow-Holm Bayproposed by NRH directions ofTonigala granite and Ongul Island.

result of Dngul Island~ Sri Lanka is rotated to LUtzow-Holm Bay adjusting thedeclination of Tonigala granite to that of Dngul Island. The NRHinclinations of Tonigala granite and Ongul Island are consistent each other,as 1=56.8° and 1=59.1° respectively, suggesting higher possibilitY of thisreconstruction model. This model has no discrepancy with recentreconstruction models being considered by geolQgy, geochronology, and 200Umisobath.

5. Conclusions

Tdnigala and Pink granite have stable NRH carried by magnetite, and thestable NRH was magnetized at late Cambrian to middle Ordovician. Gallodaidolerite was magnetized at late Jurassic, although magnetic minerals (lowtitanium titanomagnetite) have been oxidized partially. These results areconsistent with previous paleomagnetic study for Sri Lanka. Biotite gneissalong Gallodai dolerite was remagnetized by the dolerite intrusion at lateJurassic. 1I0wever other gneiss, migmatite and pegmatite did not make asignificant cluster of NRH directions.

Sri Lanka was rotated to East Antarctica referred VGPs of Ton iga lagranite, Gallodai dolerite, Ongul Island and Ferrar dolerite. Consequently,Sri Lanka is situated at offing of eastern Queen Haud Land including L~tzow­

Holm Bay. The most reliable reconstruction of Sri Lanka and LUtzow-Holm Baywas proposed based on the NRH directions.

References

Barron, E.J., Harrison, C.G.A. and Hay, W.W.(1978): Ame. Geophys. Union,Trans. 59(5),436-449.

Collerson, K.D. and Sheraton, J.W. (1986): In J. Pickard (Editor), AntarcticOasis, Academic Press, Sydny, pp21-62.

Holzl, S. and Kohler, H. (1987): Abstract, Geol. Survey Oep. of Sri Lanak,Spec. Publ. IGCP 236.

Funak!, H., Yoshida, H. and Vitanage, P.W. (1989):. Geological Journal of SriLanka. in .contribute.

Grew, E.S.and Hanton, W.I. (1979): Science, 206,443-444.Kroner, A., WilLiams, I.S., Compton, W., Baur, N., Vitanage, P.W. and Perera,LR.K. (1987): J. Geol., 95,775-791.

Yoshida, H. and Funaki, M. (1987): Abstract, Geol. Survey Ilep. of Sri Lallka,Spec.PubL IGCP 236.

Yoshida, M., Funak!, H. and Vitanage, P.W. (1989): J.Geol. Soc. of India,33(1), 71-75.

66

Rock Magnetism and Paleogeophysics

Permuted Index for Volumes 1-16

the Fission Track Age ofof Geomagnetic Field from

Occurrence of Excessand N. Takaoka, Excess

of Fission-Track Ages (1)by Chiba University,

Izu Oshima Lava Flow inField from 1 m.y.BP to

of East Asia During LastField During the Last

the Japanese Islands forDuring the Past

Implication of PrimordialExcess 129Xe and High

in Japan during the Lastwith Relatively Low

I. Kaneoka and M. Yuasa,K. Saito and M. Ozima,

Ozima, and M. Yanagisawa,I. Kaneoka and K. Aoki,

E. Takahashi, Rb, Sr anda K. Saito and M. Ozima,

Variation in the RecentPaleointensity at the

the Occurrence of aboutOzima, Anomalously High

Inclination sinceDesign of Coils for

Kono, Changes in TRM andVariation of One-Axis

T. Nakayama, and H. Doi,Funaki and H. Sakai, NRM

Note on the Experimentaland Neutron

Correlation of Igneous- An Estimation of the

of about 80 M.Y. VolcanicPleistocene Volcanic

Duration of MagneticOtofuji, N. Isezaki, Y.Liu, G.Z. Fang, and Y.

the South Fossa Magna andIn the Izu Peninsula andof Daruma Volcano and

Evidence of Majorin Malawi and Kenya,

Nodules in SouthPeridotites in South

Noise and Stability ofof Late Cretaceousfrom Fission Track

Kuramoto, and K. Yaskawa,Late 1. Kaneoka, K-Ar

of the Plio-PleistoceneCentral Japan - K-Ar

and M. Yuasa, 40Ar-39ArSakai, K-Ar,40 Ar-39 Ar

Cretaceous to Miocenewith the Fission Track

Paleomagnetism and K-ArO. Matsubayashi, K-Ar

Ozima, 40Ar-39Ar Isochronand Fission Track

Paleomagnetism and K-ArIshida, The PaleomagneticThe List of Fission-Track

Results and Fission Trackthe Variation and K-Ar

0.12 Ma Ash Layer with 91 m.y.BP to 2 m.y.BP 4129Xe Associated with 12129Xe and High 3He/4He 4(1970-1978) The List 91980-1985 Conducted 141986 Magnetization of 152 m.y.BP of Geomagnetic 420 My Inferred from Polar 142,000 Years Geomagnetic 625,000 Y.B.P. Chart over 1530,000 Years in Japan 53He Degassing on an 43He/4He Ratios in Olivine 440,000 Years Variation 640Ar/36Ar Ratios in 1240Ar-39Ar Age Studies on 1540Ar-39Ar Ages of Basalts 240Ar-39Ar Ages of Some 540Ar/39Ar Analyses of 440Ar/39Ar Analyses of 340Ar-39Ar Isochron Age of 360,000 Years Found from 175,000 Years B.P. Sakai, 1680 M.Y. Volcanic Activity 5(87Sr/86Sr) Ratio from 19,000 y.B.P. in Japan 10AF Demagnetization 6ARM in a Basalt due to 12ARM with Angle Intensity 5Abrupt Jump in the Oda, 16Acquisition Mechanisms 13Acquisition of Remanence 8Activation Analysis 6Activities of Granitic 9Activity Duration of a 8Activity in the Deccan 5Activity in the Fossa 6Activity of the Late 13Adachi, H. Inokuchi, Y. 14Adachi, H. Morinaga, Y.Y. 16Adjacent Areas, Japan - 15Adjacent Areas, Japan, 14Adjacent Areas, Northwest 9Aeolian Origin Pacific: 12Africa Precambrian Rocks 6African Kimberlites 12African Kimberlites 4Ag-AgCl Electrode 12Age the Nohi Rhyolite 12Age Dating New Evidence 13Age Determination of T. 15Age Determination of the 9Age Group in the Northern 5Age Studies of Region, 6Age Studies on Igneous 15Age and Sr Isotope H. 13Age from the Go River 9Age ofO.12Ma Ash Layer 9Age of Cretaceous Rocks 8Age of Shiga Welded Tuff, 3Age of a Mugearite M. 3Age of the Miocene 8Age of the Volcanic Rocks 5Age-Determination of the 14Ages (1) (1970-1978) 9Ages Obtained from the 5Ages in Easter Island, 15

13 Paleomagnetism and K-Ar99 and M. Ozima, 40Ar-39Ar89 Paleomagnetism and K-Ar

139 and Fission-Track117 F.A. Podosek, Radiometric

23 Saito and M. Ozima, K-Ar1 M. Yanagisawa, 40Ar-39Ar

99 and H. Kinoshita, K-Ar80 S. Okada, and N.8 Induced by Heating in

23 Magnetic J. Furuya, H.95 and T. E. Kikawa, T.

151 M. Kono and S.139 H. Kinoshita and T.

72 T. Furuta, and T.89 of Ohdateno Remain in53 Kuroko Mining Area,n Collected from West84 Harding Lake in Interior

130 M. Ozima and E.C.85 M. Ozima and E.C.81 M. Kono, Computer34 Characteristic to Some42 Ice Layers Collected from81 Magnetization of CuoCo

102 of the Narrow Zone23 the Numajiri Hydrothermal

146 from the Hydrothermal72 Minerals in Hydrothermal1 Methods Using1 H. Domen, Chemical and

55 Containing67 Cenozoic Rocks ffom the49 Paleogene Deposits27 The List of Y.17 Otofuji and T. Matsuda,81 Thermo-Magnetic and X-Ray

100 and H. Domen, Errors in30 and K. Aoki, 40Ar/39Ar72 Rb, Sr and 40Ar/39Ar57 and Neutron Activation39 and Thermomagnetic24 K. Kobayashi, Spectral17 Note on Thermomagnetic53 H. Momose, Thermomagnetic75 Report on Thermomagnetic89 H. Domen, Thermomagnetic

130 in the Spherical Harmonic94 of the Spherical Harmonic29 Sakai, Spherical Harmonic30 Kono, Spherical Harmonic15 of the Spherical Harmonic

111 M. Kono and H. Tanaka,69 H. Tanaka and M. Kono,

100 of the Reconstructed53 Paleomagnetic Study in48 Tertiary and Quaternary41 near Ayacucho, Peruvian13 aCross the Peruvian46 Building in the Central79 Studies of the Central81 Direction of a Miocene22 Found in Ojima65 of Remanence in the40 of Plio-Pleistocene

117 Magnetic Study of73 of CRM and TRM in,some25 on Paleomagnetism of

67

Ages in Hiba-oa Island, 14Ages of Basalts Dredged 2Ages of Himeji Volcanic 2Ages of Kimbo Volcano, 11Ages of Meteorites 6Ages of Six DSDP Leg 17 1Ages of Some Yamato and 5Ages of Volcanic Rocks of 10Aida, Ferromagnetic 4Air of a Basalt 4Akai, and T. Furuta, 6Akimoto, H. Kinoshita, 9Akimoto, Magnetic 2Akimoto, Paleomagnetic 14Akimoto, Paleomagnetic 9Akita Prefecture 16Akita Prefecture, Japan 15Akiyoshi Plateau, Japan 16Alaska, U.S.A. from 12Alexander, Jr., Rare Gas 3Alexander, Jr., Some 3Algebra for Automatically 16Alkaline Basalts in 3Allan Hills, Antarctica 11Alloy on a Remanent 6Along the Indus-Zangbo 14Alteration Zone, in 12Alteration Zone of Quartz 13Alteration Zones and 16Alternating Field 4Alternative Magnetic 6Aluminium 3Amakusa Islands, of the 9Amakusa-Shinojima, 14Amano and S. Nishimura, 9Amount of Clockwise Y. 13Analyses of Japanese Iron 4Analyses of NRM Using 9Analyses of Phlogopite 4Analyses of Xenolithic 3Analysis Thermomagnetic 6Analysis of Basalt 11Analysis of Geomagnetic 6Analysis of Some 11Analysis of Tholeiitic 4Analysis of Volcanic Ash 8Analysis of the 9Analysis of the Problem 3Analysis of the 1Analysis of the H. 6Analysis of the M. 1Analysis of the 2Analysis of the 10Analysis of the 10Ancient Kiln Magnetism 2Andean Peru: Cretaceous 9Andean Volcanic Rocks, 9Andes Ocros Dike Swarm 10Andes Gravity Anomaly 15Andes Yamamoto, Mountain 15Andes Ocola, Geophysical 9Andesite Dyke from the 11Andesite, Fukui 6Andesite Pumice with 14Andesites Come from the 3Andesites from the 14Andesitic Rocks 5Andesitic Rocks from the 3

75n452194988450141882172

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551

of One-Axis ARM withI. Muroi, Error

Field Damagnetization andMagnetic Susceptibility

of SusceptibilityInferred from Magnetic

M. Torii and N. Ishikawa,Inokuchi, and K. Yaskawa,Nakajima and K. Hirooka,

S. Zashu, and M. Ozima,and N. Matsuda, Magneticand H. Inokuchi, Magnetic

and M. Kono, GravityK. Kobayashi, MagneticStructure and Magnetic

from Allan Hills,Ellsworth Mountains, West

Reconstruction withYamato Meteorites from

Group in McMurdo Sound,Valley, McMurdo Sound,

of 1. Kaneoka and K.of N. Takaoka, and K.Zashu, 1. Kaneoka, and K.

from Paleomagnetism onLow Determination, 2.Y. Notsu, A Paleomagnetic

during Its Growth - Anthe - A Paleomagnetic

H. Sakai, K-Ar,40 Ar-39and H. Sakai, K-Ar,40

Danhara, Y. Itoh, M.in the South Ryukyu

History of the Ryukyuof on the Central Ryukyu

of the South RyukyuRocks from the Island

Hokuriku K. Hirooka,Experimental Data on the

Intensity Deduced fromIntensity Deduced from

Magnetic Surveying ofand C. Shimamura,H. Shibuya, Several

Hirooka and K. Tokieda,Shibuya and T. Nakajima,

in Miocene: YatsuoRocks in the Chubu

Age from the Go RiverFurutobe Kuroko Mining

Case Study in the InuyamaI) System in Inuyama

Complex Rocks, MalekhuJapan of the Matsuzaki

Bodies, Chichibu MiningPaleozoic Rocks of Tansen

in Yanagawa and TakadateShikoku Basin and DaitoRocks of the Billefjorden

and Zone, the BoundaryRocks around the Yatsuo

Rocks in the WesternIslands, Westernmost

from the Western CoastalFossa Magna and Adjacent

Peninsula and AdjacentVolcano and Adjacent

in the 1. Kaneoka, Thein the Magnetization of

St. Analysis of Volcanicof Komyoike Volcanic

of a Water-Laid VolcanicEpisode in a Volcanic

the Water·Laid Volcanicthe Water-Laid Volcanic

Magnetization of DiluvialPaleomagnetism of the

Wandering Path for East

Angle Variation 5 1Angles ,,:ithin a Specimen 5 34Anhysteretic Remanence 4 22Anisotropy of Chondritic 8 75Anisotropy of the 5 27Anomalies Boso Peninsula 16 4Anomalous Magnetic 11 55Anomalous Natural H. 15 11Anomalous Remenent T. 6 52Anomalously High 1 102Anomaly, Crustal 14 95Anomaly Lineations in the 5 118Anomaly across the 15 65Anomalyand Tonouchi and 6 107Anomaly in Southern Part 14 96Antarctica Collected 11 75Antarctica from the 13 35Antarctica of Gondwana 14 86Antarctica Ages of Some 5 84Antarctica of Beacon 9 80Antarctica in Wright 9 88Aoki, 40Ar/39Ar Analyses 4 130Aoki, Possible Occurrence 12 89Aoki, Sr Isotope Studies 6 97Apparent Polar Wander 16 57Applicability to High and 10 16Approach to Possible and 6 113Approach to Study the 4 147Approach to the Origin of 1 77Ar Age and Sr Isotope 13 48Ar·39 Ar Age and Sr 13 48Araki, 1. Katsura, and T. 15 4Arc Miyako-Jima Island 16 44Arc - Arc - Kinematic 16 47Arc - Kinematic History 16 47Arc Inferred from 14 38Arc in the Western 2 66Archaemagnetic Study in 1 29Archeo-Magnetic Field 3 22Archeological Objects 6 61Archeological Objects in 12 12Archeological Sites 8 81Archeomagnetic Nishitani 16 30Archeomagnetic 11 1Archeomagnetic Results of 6 18Archeomagnetism of H. 6 10Area Hokuriku District 11 51Area and Neogene 13 12Area - Clockwise 9 41Area, Akita Prefecture, 15 41Area, Central Japan A 10 87Area, Central Japan {Part 6 121Area, Central Nepal 14 68Area, Izu Peninsula, 10 61Area, Japan Diorite 13 60Area, Lesser Himalaya, 13 39Area, Northeast Japan 16 51Area Obtained by the Deep 5 111Area, Southwest Mesozoic 15 64Area between Northeast 1 92Area in Toyama Neogene 14 42Area of Baragoi, Northern 12 59Area of Southwest Japan, 12 44Area of the Kii Peninsula 11 55Areas, Japan - Present 15 39Areas, Japan, and Its 14 24Areas, Northwest Izu 9 17Argon-40/ Argon-36 Ratio 1 106Artificial Sediments 4 61Ash Erupted from Mount 8 57Ash Horizon Sediments in 5 49Ash Layer in the Osaka 1 65Ash Layer with the 9 13Ash Layers in from 3 41Ash Layers in the Osaka 2 34Ash of Central Yamaguchi 4 36Ashitaka Dike Swarm 9 9Asia Inferred from Polar 14 80

Translation of EastSpecial Emphasis to East

of Excess 129XeA Computer Controlledof Water in Cytherean

Rate Gases in the EarthOzima, Evolution of the

3He Degassing on anM. Kono, An

NRM H. Inokuchi,Susceptibility by Using

and Y. Nishi, AnComputer Algebra for

Results from the CentralOcros Dike Swarm near

Osaka Properties of theStudy K. Kodama and T.

M. Torii, CharacteristicMeasurements on

in the Western Area offrom Mid-Atlantic Ridge

Highly Oxidized SubmarineAnalysis of Tholeiitic

Magnetization of Cenozoicof Some Late Cenozoic

Magnetic Properties of aof Karatsu Cenozoic

Nishitani, Inclination of597C Analysis of

Study of Holocenein TRM and ARM in a

Cleaning of HoloceneColumbia River Tertiary

Magnetic Investigation ofMagnetization of Oceanic

Magnetization ofOzima, 40Ar-39Ar Ages of

Japan to Some AlkalineMeasurements on Leg 55

Present Status and a Dataof the Geomagnetic Field

of the Geomgnetic FieldWright Investigation ofEastern Part of the Japan

of the Philippinein the Melanesia

Pelagic Clay in PenrhynSediments of Shikoku

from the Central PacificCollected from Osaka

Rocks around MatsushimaPaleomagnetism of Osaka

Sound, Magnetizations ofof the Setouchi VolcanicRed Chert in the Tamba

History of the RyokeStudy on Rocks from Ryoke

and Mesozoic Rocks of theCore Samples from Lake

on the West Coast of Lakeon the East Coast of Lake

Paleomagnetism of LakeYears Found from the Lake

Organic Elements in LakeSpecial and K. Hirooka,in S. Sasajima, Possiblea Volcanic T. Nakajima,

Total Force at thefrom Planktonic T. Sato,

Path for the South ChinaIts of Northeast Japan

Magnetic Studies of theZone of Quartz Diorite

of Chichi-Shima Rocks ofthe Northern and Southern

in Southern Part ofStructure in the South

Shin'etsu-Bozu Zone, the

Asia During Last 20 My 14 80Asian Re~ults Obtained 6 90Associated with 12 89Astatic Magnetometer 6 143Atmosphere On Deficiency 2 79Atmosphere The Origin of 6 86Atmosphere: Continnous or 1 111Atmospheric Evolution 4 151Attempt of Paleointensity 1 88Attempt to Normalize the 4 39Automatic on Initial 16 20Automatic Spinner 16 24Automatically Solving 16 8Axial Zone of Hokkaido 12 25Ayacucho, Peruvian Andes 10 105Azuki Tuff in Pleistocene 15 4Baba, A Magnetratigraphic 14 52Back-Arc Spreading of the 10 80Baked Earths in Kyoto 11 1Baragoi, Northern Kenya 12 59Basalt (87Sr/86Sr) Ratio 1 102Basalt of TRM in a 2 5Basalt Thermomagnetic 4 8Basalt Come from 4 106Basalt Group in Datong 8 9Basalt Induced by Heating 4 18Basalt, Saga Prefecture, 4 116Basalt Samples from Deep 10 129Basalt Samples from Hole 11 91Basalt at Kasa-Yama, 5 47Basalt due to Laboratory 12 72Basalt from Kasa-Yama, 6 59Basalt in Washington, of 4 114Basaltic Rocks from Rock 9 106Basalts M. Joshima, 1 9Basalts Thermoremanent 3 10Basalts Dredged from M. 2 71Basalts in Southwest 3 1Basalts in the Early 6 61Base for Future Studies 15 39Based on the Inclination 1 118Based on the Inclination 2 91Basement Complex in 9 88Basin in the 15 50Basin to the Development 4 108Basin on Paleomagnetism 4 95Basin, South Pacific: of 12 53Basin and Daito Area 5 111Basin near the Equator 10 38Bay the Young Sediments 6 14Bay, Northeast Japan and 15 47Bay Sediments Yaskawa, 4 76Beacon Group in McMurdo 9 80Belt. Part 1. Study 6 105Belt, Southwest Japan 6 130Belt by Fission Track 11 103Belt in Yanai-Oshima 13 66Bi1lefjorden Area, 15 64Biwa of Deep Drilling 10 33Biwa, Central Japan 5 55Biwa, Central Japan 6 48Biwa Sediment Natsuhara, 3 24Biwa Sediments 60,000 1 34Biwa and the Climate 3 106Blake Episode with 6 90Blake Event as Revealed 1 47Blake Polarity Episode in 9 13Blast by Gun Powder - 16 1Bleaching of ESR Signals 10 7Block Polar Wander 16 57Block and the Timing of 15 56Bocaiuva Iron Meteorite 14 IBodies, Chichibu Mining 13 60Bonin Islands, Japan 10 137Borders of Northeast on 15 56Boso Peninsula, Chiba, 14 96Boso Peninsula Inferred 16 4Boundary Area between 1 92

68

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Chert in the Tamba Belt,Cherts: A Case Study inCh'i-Lin-Ts'o, Tibet asChiba, Japan in SouthernChiba University, HakoneChichi-Shima Rocks ofChichibu Mining Area,Chile and VolcanicChile and VolcanicChina of a Stalagmite,China Basalt GroupChina Block PolarChita PeninsulaChondritic MeteoritesChron at Hole 650 (LegChronology of the LateChronology of the and T.Chubu Area of CretaceousChubu District:Chugoku, Southwest JapanChun, K. Maenaka, and S.Circular Symmetric CoilCity, SouthcentralCity, West End ofCity, West JapanCity, Yamaguchi TaikazanClassification of NobleClassified NaturalClay MagnetizationClay Viscous RemanentClay in Penrhyn Basin,Clays near Komyoike,Cleaning of HoloceneClimate Organic ElementsClockwise Rotation in theClockwise Rotation ofClockwise Rotation ofClockwise Rotation ofClockwise Rotation ofClockwise Rotation of theCoast of Lake Biwa,Coast of Lake Biwa,Coastal Area of the KiiCoil Magnetic FieldCoils for AF M.Collapse in LimestoneCollected atCollected from AllanCollected from HardingCollected from Osaka BayCollected from West in aCollected from off NewCollected from theCollision ZoneColombia MagnetizationColorado, U.S.A. of theColorado, U.S.A. of SanColumbia River TertiaryComments on Rare Gas andComore Islands, IndianComparison of theCompiled in OsakaComplex MagnetizationComplex StudyComplex Rocks, MalekhuComplex, SW JapanComplex, YamaguchiComplex in Wright Valley,Component of RemanentComponentsComponents of GeomagneticComposition of CretaceousComposition of MagnetiteCompositions in DiamondsComputer Algebra forComputer ControlledConcentration in MetalConducted by Chiba

Southwest of Permian RedPaleomagnetism of Red

Secular Change inPart of Boso Peninsula,

Volcanoes Conducted byRemanent Magnetization of

of Quartz Diorite Bodies,Rocks in NorthernRocks in Northernin Ping Le, South

in Datong Province, NorthWander Path for the South

of Tokoname Group inAnisotropy of

Recorded in the BrunhesMagnetostratigraphy and

Yokoyama, Paleomagneticand Neogene Rocks in the

Tectonic Setting of theGranitic Rocks in Eastern

Sasajima, Preliminary L.Kono, Magnetic Field in a

from the Vicinity of UbeCome from Shimonoseki

District, MasudaDistrict, Tokuyama

the Earth's Interior ­H. Domen and H. Muneoka,

in Deep-Sea SiliceousMagnetization of PelagicMagnetization of Pelagic

Marine and NonmatineBasalt Magnetic Field

in Lake Biwa and theEvidence for Pleistocene

from the Go River Area ­and T. Matsuda, Amount of

Evidence for RapidYokoyama and A. Dharma,

Matsuda, and Y., Otofuji,Group on the WestGroup on the East

Dyke from the Westernin a Circular Symmetric

Kono, Optimum Design ofAge Determination of

of Flowstoneof Dirt Ice Layers

Lake of a Sediment Coreof the Young Sediments

Stalagmite (Speleothems)of a Phosphorite ModuleDeep-Sea Sediment Core

Paleomagnetism of the Izufrom the Nevado Del Ruiz,

San Juan Volcanic Field,Juan Volcanic Rocks from

Remanent Magnetzation ofE.C. Alexander, Jr., Somefrom Reunion and Grande

Directions of Y. Inoue,Japan Measured and

of Ibaragi Gral\iticof the Ibaragi GraniticObserved in Nawakot

in Jurassic Subductionof the Koyama Intrusive

Investigation of BasementM. Torii, Secondary

of Noble GasMeasurement of Three

Granitic and Chemicalfrom H. Ueno, Chemical

Ozima, Rare Gas IsotopicAutomatically M. Kono,

and M. Yoshida, AHistogram of Nickel

Izu and Hakone Volcanoes

55273228388544275573

51885

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Boundary in the Kobiwako 5Boundary in the Osaka 14Brief Note on the H. 2Brunhes Chron at Hole 650 15Brunhes Epoch Discovered 6Brunhes Normal Epoch: A 6Brunhes Normal Polarity 1Brunhes/Maruyama Polarity 14Brunhes/Matuyama Polarity 5Building in the Central 15CRM and TRM in Some 5Cajamarca, Northern Peru 12Calcareous Microfossils 8Carolines Basaltic Rocks 9Case Study in the Inuyama 10Catastrophic? of the 1Cations between Two 2Caused by Changes in the 1Caused by Redistribution 2Caused by Thunderbolts 6Cave - - An 15Cave Site, and the 6Cave by Paleomagnetism of 15Cenozoic Geomagnetic 1Cenozoic on Leg 6Cenozoic Basalt Come from 4Cenozoic Basalt Group in 8Cenozoic Basalt, Saga 4Cenozoic Deposits in the 8Cenozoic Rocks from 2Cenozoic Rocks from the 9Cenozoic Rocks from the 10Central Andes Yamamoto, 15Central Andes 9Central Axial Zone of 12Central Eastern Kyushu 13Central Equatorial of 13Central Honshu, Japan 4Central Japan 10Central Japan Drift 10Central Japan Case Study 10Central Japan Dike 11Central Japan of 11Central Japan of 3Central Japan Recorded 4Central Japan on the 5Central Japan in the 6Central Japan on the 6Central Japan Part 8Central Japan - An of 8Central Japan - K-Ar Age 6Central Japan (Part I) 6Central Java 15Central Nepal Complex 14Central Pacific Basin 10Central Part of the Japan 15Central Ryukyu Arc - 16Central Yamaguchi Study 14Central Yamaguchi 4Chain Dredged from Suiko 3Chain and Their Dredged 2Challenger II Project, 5Change Obtained from the 3Change in Ch'i-Lin-Ts'o, 16Change to a Slightly Less 11Changes in Magnetic 4Changes in TRM and ARM inChanges in the DipoleChanges of MagnetizationChannell and M. Torii,Characteristic Back-ArcCharacteristic to SomeCharacterization of FineChart over the JapaneseCheck ofChemical Composition ofChemical Composition ofChemical and Alternative

Group on Polarity EpochGroup, Polarity EpochDomen and H. Muneoka, A(Leg Recorded in the

Reversal in the LatestPolarity Episode in the

K. Yaskawa, Reversals inEpoch and T. Yokoyama,

and T. Yokoyama, Theand A. Yamamoto, Mountain

of the Directions ofPre-Inca Potsherds near

Spin Resonance Dating offrom Ponape Island, East

Area, of Red Cherts: AAtmosphere: Continuous or

by Redistribution ofin the Earth's Spin Rate

of On the Self·ReversalRemenent MagnetizationExample for Yuri-no-ana

of Sempukuji Remains, theof Collapse in Limestone

Paleointensities in the55 Basalts in the Early

Remanent Magnetization ofDatong of Some Late

Magnetzation of KaratsuPaleomagnetism of the

on Paleomagnetic Study onAmakusa Study of the

Magnetic Study of theMountain Building in the

Studies of theResults from the

Miocene Igneous Rocks InDeep-Sea Sediments in thein Southeast Hokkaido and

Izu Peninsula,of the Izu Peninsula,

in the Inuyama Area,Swarm, Oshima Island,

Several Tertiary Dykes inPaleozoic Greenstoness in

in Ontake Tephra, Ina,West Coast of Lake Biwa,

Yatsugatake Volcanoes,East Coast of Lake Biwa,

of the Izu Peninsula,the Shidara Dike Swarm,the Fossa Magna Region,System in Inuyama Area,

Sediments in Sangiran,Rocks, Malekhu Area,

PHI Recovered from theRocks Dredged from the

Kinematic Study on theof Andesites from the

of Diluvial Ash ofSeamount in the Emperor

from Ridges in the LineCruise Leg 58, by GlomarK. Maenaka, The Polarity

Tibet as SecularOn the Irreversible

Properties of a M. Kono,a Basalt due to M. Kono,

Spin Rate Caused byand Its Relation to the

Two "Events" J.E.T.S. Sasajima and M. Torii,Impure Titanomagnetites

Suspension Method:T. Nakajima, Isomagnetic

K. Manabe, ConsistencyPaleomagnetism and

Magnetite from H. Ueno,Magnetic Field H. Domen,

69

of

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andH.

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10461157362

1111

Data on the Inclination 1Data from Inclination 1Data Analysis of the 3Data Kono, Statistics of 6Data Base for Future 15Data: a Correction 2Data from the Paleozoic 15Data in Parallel Sections 3Data of the Cretaceous 9Data on the 3Dated Pyroclastic Flows 6Dating of the Ryoke 11Dating New Evidence 13Dating Inferred from 16Dating in Yanagawa and 16Dating of Calcareous 8Datong Province, North 8De- and Re-Magnetization 3Decay of I. Katsura, and 8Deccan Traps, India M.Y. 5Declination Data Based 1Declination Data Field 1Declination Data: a 2Decomposition of 9Deduced from Geomagnetic 6Deduced from of 12Deduced from Variation 14Deduced from the NRM of 2Deep Drilling Core 5Deep Drilling Core 10Deep Sea Drilling Daito 5Deep Sea Drilling Project 10Deep-Sea Cores Intensity 6Deep-Sea Sediment 8Deep-Sea Sediment Core 4Deep·Sea Sediment Cores 1Deep-Sea Sediments 4Deep-Sea Sediments Model 4Deep-Sea Sediments in the 13Deep-Sea Siliceous Clay 11Deep-sea Cores 6Deficiency of Water in 2Deflected Remanent 13Deformation of the Narrow 14Deformation of the Three 15Deformation on a Remanent 6Deformational Phenomena? 15Deformations of the for 10Degassing on an 4Del Ruiz, Colombia 14Demagnetization Optimum 6Demagnetization Equipment 16Demagnetization Dharma, 9Demagnetization Using 2Dependence of 5Depositional Remanent on 6Deposits Metallogenetic 2Deposits Study 14Deposits; Preliminary 14Deposits in Southeast 4Deposits in Yamaguchi 2Deposits in the 8Deposits in the Tokachi 8Deposits in the 6Depth Lag of NRM in 4Derived from Four 6Desiccation 8Design of Coils for AF 6Detailed Variations of 4Determination, 1. 10Determination, 2. 10Determination Using a 4Determination by a and 3Determination of Collapse 15Determination of 4Determination of Noble 2Determination of 6Determination of the Late 9

and Declinationand Declination

Gemagnetic InclinationPaleomagnetic Inclination

- Present Status and aand Declination

Preliminary Paleomagneticof Magnetostratigraphic

A Couple of PaleomagneticH. Domen, Experimental

of the from the TwoBelt by Fission Track

from Fission Track AgePaleomagnetism and K-Ar

Study and Fission-TrackElectron Spin Resonance

Cenozoic Basalt Group inin the by the Stepwise

S. Sasajima, Origin ofVolcanic Activity in the

on the Inclination andfrom Inclination and

on the Inclination andO. Oshima, Reduction

Field Intensitythe Geomagnetic Intensity

of the Geomagnetic Fieldand Kitakami MountainsMagnetism in Moriyama

Samples Measurements ofArea Obtained by the

of Basalt Samples fromDerived from Four

Microfossils inMinerals in the

Field Intensity inMagnetic Stability of

and Depth Lag of NRM inCentral Stratigraphy of

Remanent Magnetization inField Intensity in Four

Cytherean S. Matsuo, Onand M. Torii, WesterlyEvidence for Tectonic

Study of Eastern Tibet ­Effects of a Plastic

Sedimentological orNorthward Drift and Local

of Primordial 3Hefrom the Nevado

Design of Coils for AFMagnetometer with Thermaland T. Yokoyama, Thermal

A Furnace for ThemalH. Tanaka, Field

Effects of Drying on PostEpoch of Kuroko

of Cretaceous- Paleogeneof the Hishikari Gold

Minerals in Pyroclasticof the Diluvianof the Cenozoic

Late Neogene to QuternaryPyroclastic Fall

Deep-Sea Model andDeep-Sea Field Intensity

in Wet Sediments duringM. Kono, Optimum

Kawai, and K. Kobayashi,Method of PaleointensityMethod of Paleointensity

Single Field IntensityN. Ueno, Paleointensity

in and K, Yaskawa, AgeN. Ueno and M. Kono,

Experiment on Quanitativeand J. Matsuda, On the

I. Kaneoka, K-Ar Age

6 853 47

10 294 616 88

16 568 94

12 13 54 11 1112 246 143

11 619 1022 845 11

12 64 9

10 3810 3312 111 1011 4

1 596 166 412 91

11 1129 276 78

14 6611 4512 44

9 6112 29

2 592 544 1189 53

11 638 40

13 3014 5914 5213 16

Y. 10 859 498 388 469 61

12 5110 112

9 7212 3810 13813 12

9 4115 53

5 1111 14 155

14 95R. 14 96

16 43 186 123

11 9612 12 12 791 985 III4 22

15 49 17

10 5011 112

Confirmation of aConsistency Check ofConsistency of Onishi,Consolidation Process inConstraint of TheirConstraint on theConstraints on theConstruction of aContaining AluminiumContaining SpinelContinuous or EvolutionControl Techniques UsingControlled Astatic andConvergence between ofCooling Magma and ItsCore of Parameters ofCore Remanent MagnetismCore Collected fromCore Collected from theCore PI71 Recovered fromCore Samples from LakeCore Sediments in JapanCore from the Inland Sea,Core-Sediment from theCores Field IntensityCores Intensity DerivedCores Field IntensityCorrection InclinationCorrection for MagsatCorrelation of IgneousCorrelation of the LateCosta Rica Ridge RockCounter-ClockwiseCounterclockwise RotationCouple of PaleomagneticCretaceous Age Matsuda,Cretaceous Granites inCretaceous Granitic RocksCretaceous Granitic RocksCretaceous Granitic RocksCretaceous Granitic RocksCretaceous Granitic RocksCretaceous Koto Rhyolite:Cretaceous KotoCretaceous- PaleogeneCretaceous PaleomagneticCretaceousCretaceous Rock fromCretaceous Rocks ReportCretaceous Rocks fromCretaceous Rocks fromCretaceous SedimentaryCretaceous SedimentaryCretaceous Sediments andCretaceous Series in theCretaceous SerpentiniteCretaceous and NeogeneCretaceous to Miocene AgeCruise Part of theCruise Leg 58, by GlomarCrust Rock MagneticCrust of Trace ElementsCrustal Structure andCrustal Structure andCrustal Structure in theCrystals by the FluxCUOCo Alloy on aCurve Magnetic PhaseCurve from Giant CoreCurves of FerromagneticCytherean AtmosphereDSDP Leg 17 SamplesDaito Area Obtained byDamagnetization andDanhara, Magnetic M.Daruma Volcano and T.Daruma and Ida VolcanoesData Ionospheric Field

Magnetic A. Hayashida,K. Manabe,

and K. Yaskawa, Internalthe Y. Hamano,

and Volcanic Rocks: ATsunakawa, Paleomagnetic

I. Kaneoka, Noble GasPreliminary Report ofand Titanomaghemite

of Titanomagnetitesof the Atmosphere:

Oxygen Partial PressureM. Yoshida, A Computer

Southwest Japan and Plateof Hemoilmenite in a

Turbulent Motion in thein Moriyama Deep DrillingHarding of a Sediment

in the Deep-Sea SedimentJaramillo Eevent in the

Biwa of Deep DrillingCurve from Giant

Paleomagnetism of aPaleomagnetism of a

in Deep-Sea Sedimentfrom Four Deep-Sea

in Four Deep-seaand Declination Data: aMean Ionospheric Field

Activities of H. Ito,K. Hirooka, PaleomagneticMagnetism of Hole 504B,

Evidence for the MioceneM. Torii, and K. Koga,

Data of the H. Domen, Athe Nohi Rhyolite of Late

South· Paleomagnetism ofDeduced from the NRM of

Chemical Composition ofH. Ito, Paleomagnetism of

Paleomagnetic Study ofPaleomagnetic Results of

New Activity of the LateResults from the Late

Deposits Study ofFukuma and M. Torii, LateFujiwara and A. Morinaga,Taikazan Analysis of theon Paleomagnetic Study onKorean and K-Ar Age ofPaleomagnetic Data of theRocks in of Permian to

Paleomagnetic Study ofStudy in Andean Peru:

Outer Study on the Loweron an NRM Direction ofPaleomagnetic Study of

of Igneous Rocks of LateJapan Sea During GH78-2

Sea Drilling Project,Structures of Oceanic

from the Mantle to theMagnetic Anomaly,

Morijiri, and T. Nagao,and R. Morijiri, Study of

of Nickel Olivine SingleRemafient Magnetization of

in the ThermomagneticSecular Variation

K. Momose, ThermomagneticOn Deficiency of Water in

Ozima, K-Ar Ages of Sixthe of Shikoku Basin and

Using Alternating FieldAraki, I. Katsura, and T.

Furuta, Paleomagnetism ofAges of Volcanic Rocks of

Correction for Magsat

70

- AnJapanIsland,

Attempt of PaleointensityField Instensity

of Paleointensityof the Geomagnetic Fieldand Its Relevance to the

Magnetism of ScottishStudies of Scottish

T. Yokoyama and A.Thermal M. Torii, A.

Isotopic Compositions inthe Eastern Y. Itoh,

Activity Duration of aof the Ashitaka

of the Shidaraof the Shimokuraof the Fudeshimaof Neogene Ocros

Remanent Magnetization ofMeasurement of the

Alteration Zone of QuartzCaused by Changes in the

of NRM Using MagneticA Short Note on an NRM

Anomalous MagneticDeflected Remanent

Ishikawa, PaleomagneticInoue, Comparison of the

Remanent Magnetization ofthe Latest Brunhes Epoch

K. Momose, Native IronMomose and S. Inagaki, On

and N. Isezaki, TheStudy in Hokurikuin Kinki and Tokai

Igneous Rocks from San'inDeposits in the Tokachi

Stone" from Ii-no-UraRocks from Susa

Setting of the ChubuRock from TaikazanSetting of Hokuriku

of Belt in Yanai-OshimaOda, T. Nakayama, and H.Paleomagnetic Data of H.Measurement by Means H.Report on a H.Thermo-Magnetic and H.NRM Direction of H.Alternative Magnetic H.of NRMI. Muneoka and H.on the H.Kimura, The Natural H.Yokoyama, Progress H.Property of So-called H.Property of an H.Magnetic Study of the H.Thermomagnetic Study H.on Thermomagnetic H.on the Stability of H.Kawai: Obituary H.Paleo/Rock Magnetic H.Thermomagnetic H.

H. Muneoka and H.Analysis of the H.Study on Rocks from H.Brief Note on the H.Paleomagnetic Study H.Progress Report on H.Classified Natural H.Examples of the H.Natural Remanent H.the Natural Remanent H.the Natural Remanent H.Preliminary Report on H.Progress Report On H.

M. Funaki, I. Taguchi, J.in the Core M. Joshima,40Ar-39Ar Ages of Basalts

Determination on Permian 1Determined by the 3Determined by the 5Determined from Recent 5Development of the 4Devonian Lava Flows 5Devonian Volcanic Rocks 5Dharma, Clockwise 10Dharma, and T. Yokoyama, 9Diamonds Ozima, Rare Gas 4Differential Rotation of 13Dike Swarm of the 8Dike Swarm 9Dike Swarm, Central Japan 8Dike Swarm, Northeast 8Dike Swarm, Oshima 11Dike Swarm near Ayacucho, 10Diluvial Ash of Central 4Diluvian Deposits in 2Diorite Bodies, Chichibu 13Dipole Field Spin Rate 1Dipole Models Analyses 9Direction of Cretaceous 10Direction of a Miocene 11Direction of the Middle 13Directions from Middle 13Directions of CRM and TRM 5Dirt Ice Layers Natural 11Discovered at Shibutami, 6Discovered in the Lava 3Discrimination of K. 1Distribution of 15District Archaemagnetic 1District Sediments 3District - Further 10District, Hokkaido, Japan 8District, Masuda City, 9District, Northeastern 9District: Paleomagnetic 12District, Tokuyama City, 9District in Miocene: 11Districts, South-East End 13Doi, Abrupt Jump in the 16Domen, A Couple of 9Domen, A Note on the NRM 5Domen, A Preliminary 5Domen, A Short Note on 4Domen, A Short Note on an 10Domen, Chemical and 6Domen, Errors in Analyses 9Domen, Experimental Data 3Domen, H. Muneoka, and M. 3Domen, H. Muneoka, and T. 3Domen, On Thermomagnetic 9Domen, On Thermomagnetic 8Domen, On a Paleo/Rock 9Domen, On the 12Domen, Preliminary Report 8Domen, Preriminary Report 4Domen, Professor Naoto 6Domen, Progress Note on 14Domen, Progress Note on 11Domen, Progress Report on 10Domen, Thermomagnetic 9Domen, Thermomagnetic 13Domen and H. Muneoka, A 2Domen and H. Muneoka, A 9Domen and H. Muneoka, A 8Domen and H. Muneoka, 4Domen and H. Muneoka, 4Domen and H. Muneoka, On 4Domen and H. Muneoka, On 4Domen and H. Muneoka, On 4Domen and H. Muneoka, 10Damon and H. Muneoka, A 2Donon, and T. Nagata, 14Double Jaramillo Eevent 10Dredged from Ridges in 2

88 Age of a Mugearite22 Studies on Igneous Rocks18 Evidence for Northward87 Relative to K. Yaskawa,

108 Evidence of the Northward25 and T. Matsuda, Fast98 in Moriyama Deep

100 Measurements of Deep1 Obtained by the Deep Sea

144 Samples from Deep Sea12 Note on Effects of17 Reunion in Lavas and a9 Lava and Xenolithic

28 and S. Nishimura, Short17 of the Activity26 Evidence of the

105 Part of the Japan Sea36 Translation of East Asia32 of the Geomagnetic Field60 Years Paleointensities

114 for Snow Involving Rock99 of a Miocene Andesite

138 of Several Tertiary55 Solving Kinematic8 The Rikitake Two-Disk1 Kana, Rikitake Two-Disk5 T. Sato, Bleaching of

75 on Leg 55 Basalts in the38 Some Late Precambrian to17 of Rate Gases in the7 Samples and the

50 Ratio in the29 Gas Systematics in the41 Transitions of the69 by Fluctuations in the

106 Measurements on Baked96 Polar Wandering Path for33 Northward Translation of29 with Special Emphasis to49 Rocks from Ponape Island,51 Kobiwako Group on the66 and Northern Sulawesi,

1 and K-Ar Ages in61 Granitic Rocks in40 Igneous Rocks In Central47 Japan: Rotation of the5 of Magnetization in the

138 Paleomagnetic Study of59 Estimation of Statitical99 Joshima, Double Jaramillo22 on Notes on Integrated52 T. Nishitani, Grain Size51 and S. Sasajima, Note on96 Deformation on M. Ozima,59 I. Hattori, Metamorphic33 from the Inner Zone of77 and Stability of Ag-AgCI57 T. Nishitani,36 Dating of T. Sato,1 to Mechanism of Trace

36 the N. Kawai, Organic99 Paleozoic Rocks from the

134 Suiko Seamount in the49 Episode with Special66 Districts, South-East32 Shimonoseki City, West36 Nakajima, Blake Polarity38 of a Magnetic Polarity

106 and K. Hirooka, Blake104 Brunhes Normal Polarity

72 Event in Matuyama114 in the Brunhes Normal116 Brunhes/Matuyama Polarity137 Brunhes/Maruyama Polarity38 in the Latest Brunhes1 the Matuyama Geomagnetic

38 of the Metal10genetic7l Pacific Basin near the

71

Dredged from SuikoDredged from the CentralDrift and LocalDrift of Southwest JapanDrift of the IzuDrifting of SouthwestDrilling Core MagnetismDrilling Core SamplesDrilling Project, CruiseDrilling Project HolesDrying on Post Sasajima,Dunite Nodule fromDunites from HawaiiDuration of Magnetic ItoDuration of a Dike SwarmDuration of theDuring GH78-2 CruiseDuring Last 20 MyDuring the Last 2,000During the Past 30,000Dusts MechanismsDyke from the WesternDykes in Central JapanDynamo ProblemsDynamo System: M. Hoshi,Dynamo and PaleomagnetismESR Signals fromEarly CenozoicEarly Paleozoic Rocks ofEarth Atmosphere OriginEarth-AtmosphereEarth's InteriorEarth's Interior -Earth's Magnetic Field inEarth's Spin Rate CausedEarths in KyotoEast Asia Inferred fromEast Asia During Last 20East Asian ResultsEast Carolines BasalticEast Coast of Lake Biwa,East Indonesia WesternEaster Island, theEastern Chugoku,Eastern Kyushu IslandsEastern Part of SouthwestEastern Part of the JapanEastern Tibet - Zheng,Eerrors 1.Eevent in the Core Pl7lEffect of Repeated ShocksEffect on theEffects of Drying on PostEffects of a PlasticEffects on the IntensityEhime Prefecture, ShikokuElectrode Hamano, NoiseElectron Microprobe andElectron Spin ResonanceElements from the MantleElements in Lake Biwa andEllsworth Mountains, WestEmperor Chain fromEmphasis to East AsianEnd of YamaguchiEnd of Yamaguchi fromEpisode in a Volcanic AshEpisode in the BrunhesEpisode with SpecialEpoch Reversals inEpoch of Pre-JaramilloEpoch: A PreliminaryEpoch Boundary in theEpoch Boundary in theEpoch Discovered atEpoch and the Fine inEpoch of I(uroko DepositsEquator from the Central

3 8115 5310 <l1

1 ii10 5316 49

5 1110 33

5 III10 129

6 4011 lOi

4 13913 308 172 40

15 5314 80

6 85 95

13 5511 5511 3816 814 9713 7l10 76 <l1

13 396 8<l3 911 10<l

14 1053 5<l1 114

11 114 8014 80

6 909 10<l6 485 i3

15 258 40

13 113 1215 5015 5910 910 38

1 136 1286 406 1233 i<l

11 <l312 9411 918 854 1553 10<l

13 353 816 90

13 <l64 1O<l9 136 856 901 446 946 855 55

14 276 381 532 40

10 38

Sediments in the CentralThermal Demagnetization

Magnetization ofSpecimen 1. Muroi,

H. Muneoka and H. Domen,Analysis of Volcanic Ash

Central Japan - Anof H. Watanabe, On

Determination, 1.Northeast Japan - An

Plate Convergence betweenSasajima, Possible Blake

of Pre-Jaramillothe and M. Torii, Two

- From PaleomagneticM. Koyama, Paleomagnetic

Kitazato, PaleomagneticM. Torii, Paleomagnetic

District - FurtherK. Yaskawa, Paleomagnetic

S. Nohda, PaleomagneticI. Kaneoka, An

F. Hehuwat, PaleomagneticTrack Koto Rhyolite: New

Opened?: PaleomagneticBasin, South Pacific:

H. Ueno, PaleomagneticT. Nakajima Paleomagnetic

on an Atmosphericand the Earth-AtmosphereAtmosphere: M. Ozima,

of Speleothems - AnH. Domen and H. Muneoka,

Possible Occurrence ofKaneoka and N. Takaoka,

Y. Yaskawa, A Geomagneticand S. Nakaya, On the

K. Maenaka, On theI. Kaneoka, A Preliminary

S. Sasajima, Note on theH. Domen,

Otofuji and S. Sasajima,Thermal Demagnetization

of the and S. Mizutani,of Ferromagnetic Minerals

Pleistocene Pyroclasticof Southwest Japan ­

Morinaga, Y.Y. Liu, G.Z.T. Itaya, and T. Matsuda,

Thermomagnetic Curves ofS. Okada, and N. Aida,

the H. Inokuchi,by Changes in the Dipolethe Present Geomagnetic

Components of Geomagneticof the Geomagneticof the Geomgnetic

and Alternative Magneticof the San Juan Volcanic

M. Kono, Mean IonosphericMethods Using Alternating

of the GeomagneticH. Tanaka,

of the Geomagnetic2,000 of the Geomagnetic

on the Archeo-Magneticfrom of the Geomagnetic

Analysis of Geomagneticof the Paleogeomagnetic

of the Geomagneticof the Geomagneticof the Geomagnetic

in Sediment during aRocks with Geomagnetic

Variations of Geomagneticof the Past Geomagnetic

and of the Geomagneticof the Earth's Magnetic

Equatorial Pacific 13 19Equipment with 16 24Erimo Seamount Yamazaki, 14 91Error Angles within a 5 34Errors in Analyses of NRM 9 99Erupted from Mount St. 8 57Estimation of Swarm, 8 28Estimation of Parameters 2 84Estimation of Statitical 10 9Estimation of the Swarm, 8 17Eurasia and Pacific and 11 61Event as Revealed in a 1 47Event in Matuyama Epoch 6 94"Events" Recorded in 15 28Evidence - Hokkaido 13 15Evidence for Northward 10 61Evidence for Pleistocene 15 35Evidence for Rapid 10 77Evidence for Rotational 10 69Evidence for Tectonic 14 78Evidence for the Miocene 11 45Evidence for the 5 81Evidence for the and 6 69Evidence from Fission 13 30Evidence from Southwest 11 59Evidence of Major Aeolian 12 53Evidence of the Duration 2 40Evidence of the Northward 10 53Evolution 3He Degassing 4 151Evolution Model Samples 3 91Evolution of the 1 111Example for Yuri-no-ana 15 15Examples of the 4 104Excess 129Xe Associated 12 89Excess 129Xe and High 1. 4 139Excursion Recorded in a 16 33Excursion of the Latest 4 81Existence of 6 94Experiment on Quanitative 2 62Experimental Acquisition 8 67Experimental Data on the 3 22Experimental Study on Y. 4 53Experiments of Welded 9 1Expression of Fluctuation 1 59Extracted from the Lava 2 1Fall Deposits in the the 6 46Fan Shape Opening of the 13 6Fang, and K. Yaskawa, H. 16 57Fast Drifting of 16 49Ferromagnetic Minerals 2 1Ferromagnetic Minerals in 4 14Ferromagnetic Minerals in 4 9Field Spin Rate Caused 1 114fuW in 3 nField of Three 6 30Field Based on the 1 118Field Based on the 2 91Field Cleaning of 6 59Field, Colorado, U.S.A. 1 7IField Correction for and 11 112Field Damagnetization and 4 22Field Deduced from 14 18Field Dependence of 5 18Field Determined from 5 87Field During the Last 6 8Field Instensity Data 3 22Field Intensity Deduced 6 61Field Intensity Derived 6 16Field Intensity Examples 4 104Field Intensity in 1 59Field Intensity in Four 6 41Field Obtained from 12 18Field Reversal Remanence 8 67Field Reversals during 9 27Field from 1 m.y.BP to 2 4 99Field from Homgeneous 10 42Field from Inclination 1 124Field in Pliocene 3 56

M. Kono, MagneticThe Oscillation of

to High and Low MagneticCharacterization of

Geomagnetic Epoch and theNew Evidence from

Ma Ash Layer with thePaleomagnetism and

Paleomagnetic Results andof the Ryoke Belt by

S. Nishimura, The List ofKimboPaleomagnetism and

Paleomagnetic Study andWhen Did MagnetizationRevealed in a Pyroclastic

and of Pyroclasticof Izu Oshima Lava

Extracted from the LavaDiscovered in the Lava

of Scottish Devonian LavaObtained from the Lavafrom the Historical Lavafrom Recent Four Lava

the Two Dated PyroclasticPaleomagnetism of

Mizutani, Expression ofWatanabe and T. Yukutake,

Single Crystals by theS. Kokubun, A Ring-Core

Signals from Planktonicin the Magnetic Total

to Study the PlanetRidge Rock Magnetism and

Results of the OfunaWelded Tuff, Sigura-gura

Volcanic Activity in theStudies in the South

Reverse Magnetizationsthe Recent 60,000 YearsCaused by Thunderbolts

Site of Surface SoilsIntensity Derived from

Field Intensity inDetermined from Recent

the Holocene H. Tanaka,Gas Isotopes and Mass

Alexander, Jr., Rare GasIsland, Marquesas,

Paleomagnetism of theK. Notsu, Y. Takigami, K.

H. Kinoshita and H.Paleomagnetic Results Y.Igarashi, M. Yoshida, Y.Yoshida, and Y. Y.and T. Koshimizu, Y.Kinoshita, and R. T.N. Aida, Y.Cretaceous Y.A Computer Controlled Y.Post-Oligocene Y.M. Kono, Gravity Y.Heki, H. M. Kono, Y.Mountain M. Kono, Y.

Found in Ojima Andesite,Cretaceous K.

Y. Otofuji, Y. Inoue, S.Murata, Y. Otofuji, S.Investigation of M.Donon, and T. Nagata, M.P.W. Vitanage, M.P.W. Vitanage, M.Magnetization of Dirt M.Magnetizations of M.Acquisition M.Paleomagnetic Studies M.Magnetic Properties M.

of an Old IronmakingH. Tanaka and M. Kono, A

Field in a CircularField in the MatuyamaFields 2. ApplicabilityFine Magnetic Grains inFine Structure of theFission Track Age DatingFission Track Age of 0.12Fission Track Age of theFission Track AgesFission Track DatingFission-Track Ages (1)Fission-Track Ages ofFission-Track Dating inFix in Loose Sediments?Flow Occurring in asFlow by ThermomagneticFlow in 1986Flow of MineralsFlow of Native IronFlows Remanent MagnetismFlows in Oshima IslandFlows of HawaiiFlows of SakurajimaFlows of the Myoko fromFlowstone Collected atFluctuation of the S.Fluctuations in the H.Flux Method OlivineFluxgate for Spinner andFOraminifera of ESRForce at the Blast by GunFormation - An ApproachFormation Magnetism RicaFormation, MiuraFormation, Sumatra, ofFossa Magna Region,Fossa Magna and AdjacentFound from the IzumiFound from the Lake BiwaFound in Ojima Andesite,Found in a Pre-CeramicFour Deep-Sea CoresFour Deep-sea CoresFour Lava Flows of FieldFour Paleointensities inFractionation RareFractionation Patterns inFrench Polynesia Hiba-oaFudeshima Dike Swarm,Fujioka, and H. Sakai,Fujisawa, Measurements ofFujiwara, A PreliminaryFujiwara, M. Homma, Y.Fujiwara, P. Gautam, M,Fujiwara, S. Mukoyama,Fujiwara, S. Ogura, H.Fujiwara, S. Okada, andFujiwara and A. Morinaga,Fujiwara and M. Yoshida,Fujiwara and R. Sugiyama,Fukao, A. Yamamoto, andFukao, Y. Hamano, K.Fukao, and A. Yamamoto,Fukui PrefectureFukuma and M. Torii, LateFunahara, F. Murata, andFunahara, J. Matsuo, F.Funaki, A PreliminaryFunaki, 1. Taguchi, J.Funaki, M. Yoshida, andFunaki, M. Yoshida, andFunaki, Natural RemanentFunaki, Natural RemanentFunaki and H. Sakai, NRMFunaki and M. Yoshida,Funaki and T. Nagata,Furnace Site SurveyingFurnace for Themal

8 891 53

10 1611 801 53

13 309 138 225 73

11 1039 117

11 2116 512 151 476 49

15 12 13 175 256 254 735 876 276 681 591 1143 18

10 110 716 1

4 14714 669 49 16 100

15 3912 351 346 52

15 116 166 415 876 306 793 91

14 7511 2613 481 26

12 258 106

14 126 49

16 44 14

10 856 143

13 1515 65

9 6615 73

6 5213 1615 5914 789 88

14 116 6114 8611 75

9 8013 5513 3512 836 72 24

72

from San'in District ­Shima, K. Matsumoto, M.

Furuya, H. Akai, and T.H. Kinoshita, and T.

Hole H. Kinoshita and T.Y. Onda, S. Sugihara, T.

K. Kobayashi, T.Polarity Sequence of the

Furuta, Magnetic J.and a Data Base for

of the Japan Sea DuringGeomagnetic N. Niitsuma,

Classification of Noble1. Kaneoka, Noble

E.C. Alexander, Jr., Rare1. Kaneoka, Rare

and N. Takaoka, Rarein and M. Ozima, RareHonda and M. Ozima, Rare

Some Comments on Rareand B.J.G. Upton, Noble

1. Kaneoka, NobleThe Origin of Rate

Determination of NobleReconnaissance of P.Y. Y. Fujiwara, P.the Secondary P.

Harmonic Analysis of theA Constraint of Their

of Field in the Matuyamaand Y. Yaskawa, A

in the Presentof Three Components of

Harmonic Analysis of theSecular Variation of the

Paleointensities of theHarmonic Analysis of the

Sakai, Variation of theSpectral Analysis of

of Fluctuation of theVariation of the

Paleointensities of theof Granitic Rocks withDetailed Variations of

Homgeneous of the PastHarmonic Analysis of the

Secular Variation ofHirooka, Variation of the

H. Tanaka,M. Kono, Determination of

M. Kono,Preliminary Study of

Recorded in K. Manabe,the and K. Tachibana, A

Galactic Rotation andVariation of a Standard

M. Hyodo and K. Yaskawa,107, Tyrrhenian Sea):

the Fine Structure of theand N. Kawai, Secular

Harmonic Analysis of thethe T. Ui, and L. Ocola,the Japanese K. Hirooka,

Variation Curve fromCruise Leg 58, by

of the Hishikariof Sri Lanka in View of

of Sumatra Being Part ofGranitic Rock in the

Yamaguchi, N. Isezaki, H.T. Nishitani,

and 1. Katsura, MagneticRare Gas Occlusion into

of Fine MagneticNodule from Reunion and

of the Middle Mioceneof Cretaceous

Magnetization of Ibaragi

Further Evidence for 10Furukawa, and N. Isezaki, 15Furuta, Magnetic J. 6Furuta, Paleomagnetism of 9Furuta, Paleomagnetism of 14Furuta, and T. Akimoto, 9Furuta, and T. Ishii, 9Furutobe Kuroko Mining 15Furuya, H. Akai, and T. 6Future Studies Status 15GH78-2 Cruise Part 15Galactic Rotation and 1Gas Components 14Gas Constraints on the 8Gas Fractionation and 3Gas Isotopes and Mass 6Gas Isotopes in Hawaiian 6Gas Isotopic Compositions 4Gas Occlusion into Grains 4Gas Solubility in Liquid 3Gas Systematics in Lavas 11Gas Systematics in the 14Gases in the Earth 6Gases with a Quadrupole 2Gautam, A Paleomagnetic 13Gautam, M, Yoshida, and 14Gautam and M. Yoshida, On 14Gemagnetic Inclination 3Genetic Relationships 6Geomagnetic Epoch and the 1Geomagnetic Excursion 16Geomagnetic Field 3Geomagnetic Field 6Geomagnetic Field Based 1Geomagnetic Field Deduced 14Geomagnetic Field 5Geomagnetic Field During 6Geomagnetic Field H. 6Geomagnetic Field 6Geomagnetic Field 1Geomagnetic Field 6Geomagnetic Field Onuki, 12Geomagnetic Field 9Geomagnetic Field from 1 4Geomagnetic Field from 10Geomagnetic Field from 1Geomagnetic Inclination 10Geomagnetic Intensity K. 12Geomagnetic 5Geomagnetic N. Ueno and 4Geomagnetic 1Geomagnetic Paleosecular 15Geomagnetic Reversal 1Geomagnetic Reversal in 6Geomagnetic Reversals 1Geomagnetic Secular 12Geomagnetic Secular 6Geomagnetic, 650 (Leg 15Geomagnetic Transition 1Geomagnetic Variation in 1Geomgnetic Field Based on 2Geophysical Studies of 9Geotectonic History of 10Giant Core Sediments in 12Glomar Challenger II 5Gold Deposits; 14Gondwana Reconstruction 14Gondwanaland Possibility 5Goto Islands of Miocene 6Goto, and K. Yaskawa, S. 16Grain Size Effect on the 6Grain Size and Viscous 15Grains during Its Growth 4Grains in Sediment 11Grande Comore Islands, 11Granite from the Osumi 13Granites in South Korea 2Granitic Complex 2

69 Study of the Ibaragi50 Paleomagnetism of Miocene82 the NRM of Cretaceous17 Composition of Cretaceous66 Okushiri of Cretaceous

4 Study of Cretaceous106 Results of Cretaceous

41 ofIgneous Activities of82 Porphyllites and Tertiary39 A. Yamamoto, and M. Kono,53 Study of Sawadani

130 Japan of Paleozoic105 of the Kobe Sedimentary94 Ash Layer in the Osaka91 Sediments in Osaka79 Ash Layers in the Osaka88 Boundary in the Osaka

144 Tuff in Pleistocene Osaka147 Nonmatine Study of Osaka100 of Tokoname107 Some Late Cenozoic Basalt105 Magnetizations of Beacon86 Found from the Izumi62 Measurement of the Miyako39 the Plio-Pleistocene Age12 Plio-Pleistocene Kobiwako68 Boundary in the Kobiwako

102 into Grains during Its88 Properties and53 Single M. Ozima,33 of Flowstone Collected at22 Force at the Blast by30 from Korean Peninsula -

118 Pleistocene from the18 of the Old Somma Lavas of87 Results ofIzu and8 Process in the Y.

61 M. Kono, Y. Fukao, Y.16 Nomura, N. K. Heki, Y.59 Ui, K. Heki, Y.41 Hysteresis Properties Y.18 Tanaka, M. Kono, and Y.27 the H. Tsunakawa,-and Y.99 T. Tosha, A M. Kono, Y.42 Pure Iron at High Y.

124 Magnetic Y.23 K. Heki, Y.12 K. Heki, Y.95 Core Collected from73 Problem in the Spherical83 of the Spherical25 H. Sakai, Spherical51 M. Kono, Spherical38 of the Spherical

130 M. Hyodo, T. Ishizawa, Y.1 K. Hirooka and 1.

14 Xenolithic Dunites from28 Historical Lava Flows of53 Rare Gas Isotopes in34 and Paleomagnetism of the91 Magnetic H. Ueno, K.66 of a Magnetic A.93 M. Torii, H. Shibuya" A.1 H. ada, M. Torii, and A.

III and T. Yokoyama, The A.31 Rotational Motion of A.86 and M. Torii, A.

104 Preliminary A.58 When Was Y. Otofuji, A.38 Yokoyama, A.

128 Yokoyama, A.7 Basalt due to Laboratory

147 Using a Single80 of a Basalt Induced by

107 Suwijanto, and F.8 S. Nishimura, and F.

59 T.V. Leeuwen, and50 Y. Fukao, Y. Hamano, K.

73

Granitic Complex 3 67Granitic Rock in the Goto 6 58Granitic Rocks from 2 54Granitic Rocks Chemical 4 118Granitic Rocks from 9 53Granitic Rocks from the 11 63Granitic Rocks in Eastern 8 40Granitic Rocks with 9 27Granodirites on Permian 1 88Gravity Anomaly across 15 65Greenstones in Jurassic 11 68Greenstonessin Central 3 76Group Age-Determination 14 40Group Volcanic 1 65Group Ash Horizon 5 49Group, Sennan and Senpoku 2 34Group, Southwest Japan 14 27Group, Southwest Japan 15 4Group Using Marine and 3 32Group in Chita Peninsula 3 36Group in Datong Province, 8 9Group in McMurdo Sound, 9 80Group in Northwestern 12 35Group in the Kitakami 9 56Group in the Northern of 5 69Group on the East Coast 6 48Group on the West Coast 5 55Growth - An Approach to 4 147Growth of Instability 14 97Growth of Nickel Olivine 3 18Gujo-Hachiman 6 68Gun Powder - Total 16 1Gyeongsang Supergroup in 8 46Hakone Volcano Latest 6 30Hakone Volcano 6 82Hakone Volcanoes 14 23Hamano, Consolidation 4 61Hamano, K. Heki, H. 9 66Hamano, M. Kono, K. 10 120Hamano, M. Kono, and T. 10 105Hamano, Magnetic 6 137Hamano, Noise and H. 12 94Hamano, Paleomagnetism of 9 9Hamano, T. Nishitani, and 6 22Hamano, The Melting of 2 86Hamano and K. Yomogida, 8 75Hamano, and M. Kono, 9 i2Hamano, and M. Kono, 10 112Harding Lake in Interior 12 6Harmonic Analysis of the 3 102Harmonic Analysis of the 1 118Harmonic Analysis of the 6 8Harmonic Analysis of the 1 124Harmonic Analysis of the 2 91Hase, H. Inokuchi, N. 6 36Hattori, Metamorphic 3 76Hawaii Kapuho Lava and 4 139Hawaii from the 4 isHawaiian Ultramafic 6 88Hayama-Mineoka Ophiolite, 6 107Hayashi, and M. Nedachi, 15 41Hayashida, Confirmation 6 85Hayashida, 1. Katsura, S. 10 33Hayashida, Paleomagnetic 16 51Hayashida, S. Sasajima, 5 55Hayashida, Timing of 12 33Hayashida, Y. Otofuji, 11 61Hayashida and H. Suzuki, 15 64Hayashida, and M. Torii, 11 59Hayashida and T. 14 27Hayashida and T. 6 48Heating TRM and ARM in a 12 i2Heating Method 4 104Heating in Air 4 18Hehuwa Paleomagnetic 5 104Hehuwat, Paleomagnetic 6 69Hehuwat, Paleomagnetic 5 73Heki, H. Kinoshita, Y. 9 66

of Secular Variation K.oflnstantaneous K.K. Nomura, N. K.and T. Ui, K.Kono, Paleomagnetic K.Kono, Paleomagnetic K.Paleomagnetism of the K.

Erupted from Mount St.Magma Decomposition of

and K-Ar Ages inTakaoka, Excess 129Xe and

and M. Ozima, AnomalouslyMelting of Pure Iron at

Velocities of Solid underunder High Pressures and

2. Applicability toby Using Automatic

Self-Reversal of TRM in aIrreversible Change E.of Rotation in the Oiso

Collected from AllanGroup, Sennan and Senpoku

of Tansen Area, Lesserand K-Ar Ages of

S. Sasajima, On the T.Takai, M. Miyachi, and I.

Y. Otofuji, J.Y. Oh, T.T. Nakajima and K.

Study in Hokuriku K.S. Nishimura, and K.

Yokoyama, and S. K.History of the K.Correlation of the K.and K. Tokieda, and K.

Sasajima, Y. Otofuji, K.Sakai, and T. K.

H. Sakai and K.S. Nishimura, K.

Yokoyama, K.H. Sakai, K.

Metamorphic Effects K.N. Kawai, T. Nakajima, K.Archeomagnetic K.

Paleomagnetism of theT. Nagata, The Volumetric

Paleointensities from theRemanent Magnetization of

K. Hirooka, Geotectonicand S. Nishimura, Thermal

Ryukyu Arc - Kinematicthe Central Axial Zone ofand Oshima Peninsula of

Okushiri Island, WestRotation of SoutheastK. Tokieda, Tilting of

in the Tokachi District,Deposits in Southeast

Archaemagnetic Study inon Tectonic Setting of

Furuta, Paleomagnetism ofof Basalt Samples from

in the Brunhes Chron atDeep Sea Drilling Project

Magnetic Study ofField Cleaning of

Paleointensities in thethe Cave Site, and. thePaleointensities in the

Geomagnetic Field fromYoshida, Y. Fujiwara, M.

Gas Occlusion into M.Kitakami Mountains, N.E.

Hokkaido and CentralY. H. Morinaga, I.

Y.Y. Liu, H. Morinaga, 1.Liu, T. H. Morinaga, 1.Kono, and Y. Hamano, A.of Komyoike Volcani~ Ash

Heki, Paleomagnetic Study 6 72Heki, The Inverse Problem 11 120Heki, Y. Hamano, M. Kono, 10 120Heki, Y. Hamano, M. Kono, 10 105Heki, Y. Hamano, and M. 9 72Heki, Y. Hamano, and M. 10 112Heki and H. Tsunakawa, 8 17Helens, U.S.A. Ash 8 57Hemoilmenite in a Cooling 9 102Hiba·oa Island, 14 75High 3He/4He Ratios in 4 139High (87Sr/86Sr) Ratio 1 102High Pressures The 2 86High Pressures and High 1 26High Temperatures - 1 26High and Low Magnetic 10 16High-Temperature 16 20Highly Oxidized Submarine 2 5Hikawa, On the 11 96Hills: A Possible Record 15 35Hills, Antarctica Layers 11 75Hills, Southwestern Japan 2 34Himalaya, Nepal Rocks 13 39Himeji Volcanic 2 45Hirajima, Y. Otofuji, and 5 27Hirano, Paleomagnetism 11 21Hirasawa, K.D. Min, and 8 46Hirooka, Anomalous 6 52Hirooka, Archaemagnetic 1 29Hirooka, Blake Episode 6 90Hirooka, C. Tobira, T. 4 81Hirooka, Geotectonic 10 93Hirooka, Paleomagnetic 6 78Hirooka, Paleomagnetism 3 110Hirooka, Suparka, S. 5 104Hirooka, T. Takahashi, H. 10 53Hirooka, Variation of the 12 12Hirooka, Y. Otofuji, T.V. 5 73Hirooka, Y. Sakai, and T. 4 88Hirooka, and A. Takeuchi, 11 38Hirooka and 1. Hattori, 3 76Hirooka, and K. 1 53Hirooka and K. Tokieda, 6 18Hishikari Gold Deposits; 14 31Histogram of Nickel and 1 21Historical Lava Flows of 4 73Historical Lava at 4 72History of the Japanese 10 93History of the Ryoke Belt 11 103History of the Ryukyu Arc 16 47Hokkaido Results from 12 25Hokkaido, Mountains 6 113Hokkaido Rocks from 9 53Hokkaido - From 13 15Hokkaido Island and and 2 54Hokkaido, Japan Deposits 8 106Hokkaido and Central 4 14Hokuriku District 1 29Hokuriku District in 11 51Hole 504B, Costa Rica T. 14 66Hole 597C Analysis 11 91Hole 650 (Leg 107, 15 28Holes 597B and 597C from 10 129Holocene Basalt at 5 47Holocene Basalt from 6 59Holocene Obtained from 6 25Holocene Paleosecular 6 18Holocene and the Latest 6 30Homgeneous Sediments 10 42Homma,Y. Igarashi, and 8 106Honda and M. Ozima, Rare 4 147Honshu, Japan the South 10 85Honshu, Japan Southeast 4 14Horie, H. Maruyama, and 16 33Horie, H. Maruyama, and 15 21Horie, H. Murayama, Y.Y. 15 15Horiguchi, H.'Tanaka, M. 12 94Horizon Sediments in 5 49

Y. Nishi, An M. Kono, M.Two-Disk M. Kono and M.Zone, in the Numajiri

of Magnetite from theUeno, Opaque Minerals inH. Katao, H. Morinaga, MReconstruction of the M.Yaskawa, Internal M.Hase, H. Inokuchi, N. M.Susanto, and H. M.Geomagnetic Secular M.Paleomagnetism of a M.Paleomagnetism of a M.Preliminary Report of M.x = Y. Hamano, Magnetic

Remanent Magnetization ofStudy of the

Nedachi, Y.Urashima, K.Magnetization of Dirt

Reversed Property of anRocks of Daruma and

by Magnetic M. Yoshida,by Magnetic M. Yoshida,by Magnetic M. Yoshida,

Y. Fujiwara, M. Homma, Y.H. Ito, Correlation of

Remanent Magnetization of40Ar-39Ar Age Studies on

from Middle MioceneDistrict - of Tertiary

Paleomagnetism ofIIMagnetic Stone ll from

K. Yaskawa, M. Takagi, K.Yaskawa, T. Miki, and M.

K. H. Morinaga, H.M. Ozima and S. Matsuo,

Northeast Japan and Itsthe Line Chain and TheirNishida, and T. Katsura,

in Ontake Tephra,K. Momose and S.of the Gemagnetic

of PaleomagneticField Based on the

Geomagnetic Field fromField Based on the

Samples T. Nishitani,Variation of Geomagnetic

of Mafic and Ultramaficand T. Koshimizu,

in the Deccan Traps,Grande Comore Islands,Northern Sulawesi, East

of Sumba Island,Formation, Sumatra,

Properties of a Basaltthe Narrow Zone Along the

the South Boso Peninsulaof the Japanese Islands

Area of Southwest Japan,of the South Ryukyu Arc

of Southwest JapanCh'i.Lin-Ts'o, Tibet as

the Philippine Sea PlateMotion of Southwest Japan

Asia During Last 20 MyM. Kono and H. Tanaka,

Thermal Variation ona Core·Sediment from the

of a Core from theGranitic Rocks from the

Normalize the NRM H.Minerals in the H.

Y. Otofuji, K.H. Kim, H.and K. Yaskawa, H.Yamaguchi, M. Miki, H.H. Morinaga, M Hyodo, H.Miki, H. Morinaga, H.

Hoshi, K. Yamaguchi, and 16 2·1Hoshi, The Rikitake 14 97Hydrothermal Alteration 12 66Hydrothermal Alteration 13 60Hydrothermal Alteration 16 16Hyodo, H. Inokuchi, J. 14 75Hyodo, Possibility of 10 42Hyodo, S. Onishi, and K. 10 29Hyodo, T. Ishizawa, Y. 6 36Hyodo, W. Sunata, E.E. 15 31Hyodo and K. Yaskawa, 6 14Hyodo and K. Yaskawa, 11 10Hyodo and K. Yaskawa, 11 4Hyodo and K. Yaskawa, 12 1Hysteresis Properties of 6 137Ibaragi Granitic Complex 2 50Ibaragi Granitic Complex 3 67Ibaragi, and R. Suzuki, 14 31Ice Layers Collected from 11 75Icelandic Matuyama 8 59Ida Volcanoes in 10 50Identification of Tephras 6 107Identification of Tephras 6 112Identification of Tephras 6 118Igarashi, and T. 8 106Igneous Activities of 9 27Igneous Rocks Shocks on 1 13Igneous Rocks Dredged 15 53Igneous Rocks In Central 13 IIgneous Rocks from San'in 10 69Igneous Rocks of Late 9 41Ii-no·Ura District, 9 96Ikeguchi, and N. Kawai, 2 28Ikeya, Paleomagnetism of 13 51Imamura, H. Inokuchi, and 15 11Implication of Primordial 4 151Implication to the Time 15 47Implications Ridges in 2 71Impure Titanomagnetites 3 1Ina, Central Japan 4 81Inagaki, On 1 7Inclination Data 3 102Inclination Data 6 151Inclination and 1 118Inclination and of the 1 124Inclination and 2 91Inclination of Basalt 10 129Inclination since 9,000 10 23Inclusious from Studies 6 97Indentification of 6 49India Volcanic Activity 5 81Indian Ocean Reunion and 11 107Indonesia Western and 5 73Indonesia Paleoposition 6 69Indonesia Sigura-gura 9 1Induced by Heating in Air 4 18Indus.Zangbo Suture of 14 78Inferred from Magnetic 16 4Inferred from Histor~' 10 93Inferred from 12 44Inferred from Rotation 14 38Inferred from Drifting 16 49Inferred from Change in 16 38Inferred from of 14 72Inferred from Rotational 12 33Inferred from Polar East 14 SOInfluence of Partial 3 10Initial Susceptibility by 16 20Inland Sea, Japan {Seto 11 4Inland Sea, Japan (Seto 11 10Inner Zone of Ehime 11 63Inokuchi, Attempt to 4 39Inokuchi, Ferromagnetic 4 9Inokuchi, H. Morinaga, F. 12 51Inokuchi, H. Morinaga, 6 6SInokuchi, J. Matsuda, S. 15 25Inokuchi, J. Matsuda and 14 75Inokuchi, K. Yaskawa, T. 13 51

74

S.

and

fromRocks

C. Itoya, H. Morinaga, H.K. Yaskawa, and H.

T. Ishizawa, Y. Hase, H.Isezaki, Y. Adachi, H.Morinaga, H. Imamura, H.

H. Morinaga, H.Morinaga, M. Kamino, H.

Secular H. Morinaga, H.Isezaki, J. Matsuda, H.

Directions of CRM and Y.Murata, Y. Otofuji, Y.

Properties and Growth ofThe Inverse Problem of

the Archeo-Magnetic FieldT. Nagata, Notes on

of the Geomagnetic Fieldof the Geomagnetic

of Geomagnetic FieldPaleogeomagnetic Field

One-Axis ARM T. Sueishi,of the Geomagnetic Fieldof the Geomagnetic Field

Remanent Effects on theTRNh Normalize the NRMOn Mantle-Crust Material

A Possible Record ofRatio in the Earth's

in the Earth'sfrom Harding Lake in

Onishi, and K. Yaskawa,Blast by Gun Powder ­

Yamaguchi of the KoyamaA Case Study in the

Japan (Part I) System inK. Heki, The

S. Tanoue, PaleomagneticRocks and Rock MagneticM. Funaki, A Preliminary

Shimamura, ArcheomagneticM. Torii, Paleomagnetic

Mechanisms for Snowand M. Kono, Mean

Lava K. Momose, NativeTetrataenite in Toluca

Studies of the BocaiuvaAnalyses of JapaneseThe Melting of Pure

Analysis of SomeSurveying of an Old

E. Hikawa, On theMurata, S. Yamaguchi, N.

Inokuchi, and K. N.H. Inokuchi, H. Miki, N.of M. Furukawa, and N.

Y. Hase, H. Inokuchi, N.Matsuda, S. Yamaguchi, N.

Inokuchi, Y. Otofuji, N.Torii, T. Matsuda, and S.

Study J. Nishida and S.K. Yaskawa, and S.

T. Furuta, and T.Magnetic M. Torii and N.K. Koga, N.

M. Torii and N.Westerly Deflected N.Inokuchi, M. Hyodo, T.

of the Palau and the Yapthe Lava Flows in Oshima

Magnetic Survey in NiueVolcanic Rocks from the

Dike Swarm, OshimaRocks from Ponape

Paleoposition of SumbaRocks from the Oki-Dogo

Northern KyushuSouthern Kyushu

Rocks from Kuro-Shimaand K-Ar Ages in Hiba-oa

Inokuchi, K. Yaskawa, and 14Inokuchi, Magnetic 5Inokuchi, N. Isezaki, and 6Inokuchi, Y. Otofuji, N. 14Inokuchi, and K. Yaskawa, 15Inokuchi, and K. Yaskawa, 11Inokuchi, and K. Yaskawa, 14Inokuchi, and K. Yaskawa, 14Inokuchi, and K. Yaskawa, 6Inoue, Comparison of the 5Inoue, S. Funahara, F. 15Instability Statistical 14Instantaneous Plate 11Instensity Determined by 3Integrated Effect of 1Intensity Deduced from 6Intensity Deduced from 12Intensity Derived from 6Intensity Determination 4Intensity Variation of 5Intensity in Deep-Sea 1Intensity in Four 6Intensity of Natural 3Intensity of Sediment by 4Interaction M. Ozima, 2Interaction between the 15Interior 1Interior - Systematics 14Interior Alaska, U.S.A. 12Internal Consistency of 10Interpretation by at the 16Intrusive Complex, 9Inuyama Area, Central 10Inuyama Area, Central 6Inverse Problem of 11Investigation for the 14Investigation of Basaltic 9Investigation of Basement 9Investigation of Ohdateno 16Investigation of a 1Involving Rock Dusts 13Ionospheric Field 11Iron Discovered in the 3Iron Meteorite Lamellar 12Iron Meteorite Magnetic 14Iron Sands and X-Ray 4Iron at High Pressures 2Iron-Sands of West Japan 11Ironmaking Furnace Site 6Irreversible Change to a 11Isezaki, H. Goto, and K. 16Isezaki, J. Matsuda, H. 6Isezaki, K. Yaskawa, and 5Isezaki, The Distribution 15Isezaki, and K. Yaskawa, 6Isezaki, and K. Yaskawa, 15Isezaki, and K. Yaskawa, 14Ishida, Natural Remanent 8Ishida, Paleomagnetic 3Ishida, The Paleomagnetic 14Ishii, Reconnaissance 9Ishikawa, Anomalous 11Ishikawa, M. Torii, and 12Ishikawa, Paleomagnetic 13Ishikawa and M. Torii, 13Ishizawa, Y. Hase, H. 6Island Paleomagnetism 14Island Obtained from 6Island Report on the 6Island Arc in the Western 2Island, Central Japan 11Island, East Carolines 9Island, Indonesia the 6Island, Japan Ultramafic 3Island, Japan 4Island, Japan Kagoshima, 4Island, Kagoshima 5Island, Marquesas, French 14

40 Studies on Sumatra118 Part 1. Shodo-Shima

36 Rocks from Okushiri72 the Westcentral Kyushu11 from Northern Kyushu16 Tilting of Hokkaido

7 Study on Miyako-Jima18 and K-Ar Ages in Easter30 In Central Eastern Kyushu

5 Rocks from the Line59 Granitic Rock in the Goto97 Reunion and Grande Comore

120 History of the Japanese22 Rocks of Bonin13 Rocks from the Amakusa61 of Rotation of Tsushima12 to the of the Ryukyu16 Chart over the Japanese

104 and M. Ozima, 40Ar-39Ar1 the T. Nakajima,

59 Kaneoka, and K. Aoki, Sr41 Ar-39 Ar Age and Sr76 1. Kaneoka, Rare Gas39 and N. Takaoka, Rare Gas76 Rocks and K. Yaskawa, Sr35 and M. Ozima, Rare Gas

106 Zashu, and M. Ozima, Sr105 Volcanic J. Matsuda, Sr

6 Fast Y. Otofuji, T.29 on S. Yoshikawa, andM.1 Inclusious from

24 Igneous Activities of H.87 and S. Kume, RemanentH.

121 Notsu, A H.120 Notsu, Paleomagnetic H.46 Notsu, Paleomagnetism H.

106 Notsu, Remanent H.88 of A. Tokuyama, and H.30 Y. Notsu and H.65 Paleomagnetic Record H.55 Paleomagnetic Study H.

112 Paleomagnetism and H.17 Paleomagnetism of _. H.83 Tilting of Hokkaido H.

1 Remanent K. Suwa, H.5 Short Duration of H.

86 Rotation of the Y.99 Katsura, and T. Y.7 Paleomagnetic Study on Y.

96 of Neogene Rocks Y.38 Paleomagnetic Study Y.30 Kusakabe, F. Murata, C.

118 Inokuchi, K. Yaskawa, C.50 Paleomagnetism of the36 Remanent Magnetization of25 Volcanoes in Northwestern72 Northward Drift of the34 Northeastern Part of the32 of the Matsuzaki Area,40 Adjacent Areas, Northwest

106 Volcanics In the55 Paleomagnetic Results of44 Found from the1 Kyushu Island, West8 Rocks of Bonin Islands,

36 Prefecture, West72 Izu Peninsu.1a, Central25 Izu Peninsula, Central36 Area, Izu Peninsula,66 Mountains, N.E. Honshu,26 the Inuyama Area, Central

106 Kimbo Volcano, Southwest69 Oshima Island, Central85 Tertiary Dykes in Central

116 Rotation of Northeast72 Evidence from Southwest65 Subduction Complex, SW75 Some Iron-Sands of West

75

Island: On theIsland {PreliminaryIsland, West HokkaidoIsland, West JapanIsland, West JapanIsland and KitakamiIsland in the SouthIsland, the SoutheastIslands Igneous RocksIslands of the VolcanicIslands of MioceneIslands, Indian OceanIslands Inferred fromIslands, JapanIslands, WestcentralIslands, Westernmost AreaIslands and Its RelevanceIslands for 25,000 Y.B.P.Isochron Age of a SaitoIsomagnetic Chart overIsotope Studies of MaficIsotope Studies onIsotopes and MassIsotopes in HawaiianIsotopes in VolcanicIsotopic Compositions inIsotopic Studies ofIsotopic Studies of theItaya, and T. Matsuda,Itihara, PaleomagnetismItinomegata, JapanIto, Correlation ofIto, K. Tokieda, K. Suwa,Ito, K. Tokieda, and Y.Ito, K. Tokieda, and Y.Ito, K. Tokieda, and Y.Ito, K.Tokieda, and Y.Ito, Paleomagnetic StudyIto, Paleomagnetism ofIto and K. Tokieda, AIto and K. Tokieda, AIto and K. Tokieda,Ito and K. Tokieda,Ito and K. Tokieda,Ito, and S. Kume,Ito and S. Nishimura,Itoh, DifferentialItoh, M. Araki,!.Itoh, M. Torii, and T.Itoh, MagnetostratigraphyItoh and M. Torii,Itota, H. Morinaga, M.Itoya, H. Morinaga, H.Izu Collision ZoneIzu Oshima Lava Flow inIzu Peninsula, CentralIzu Peninsula, CentralIzu Peninsula, CentralIzu Peninsula, JapanIzu Peninsula, JapanIzu Peninsula andIzu and Hakone VolcanoesIzumi Group inJapan the WestcentralJapan of Chichi-ShimaJapan YamaguchiJapan in NorthwesternJapan Drift of theJapan of the MatsuzakiJapan the South KitakamiJapan A Case Study inJapan Ages ofJapan Dike Swarm,Japan of SeveralJapan Counter-ClockwiseJapan PaleomagneticJapan in JurassicJapan Analysis of

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Giant Core Sediments in Japan Curve from 12 1 Drifting of Southwest Japan Inferred from Fast 16 19Archeological Objects in Japan Deduced from 12 12 Motion of Southwest Japan Inferred from 12 3:1

Shikoku, Southwest Japan in Northwestern 12 35 Compiled of Southwestern Japan Measured and 6 10Outer Zone of Southwest Japan Series in the 12 38 Eastern Part of Southwest Japan: Paleomagnetic the 13 12

Zone, Northeastern Japan Alteration 12 66 in Inuyama Area, Central Japan (Part I) System 6 121Prefecture, West Japan Yamaguchi 12 77 the Tamba Belt, Southwest Japan (Preliminary in 6 130

Koto Rhyolite, Southwest Japan Pole from the 13 16 since 9,000 y.B.P. in Japan Recorded by 10 23Chichibu Mining Area, Japan Diorite Bodies, 13 60 Korea Drift of Southwest Japan Relative to South 1 ii

Prefecture, West Japan End of Yamaguchi 13 66 of Seamounts from the Japan Sea Volcanic Rocks 13 18of Stalagmites in Japan Paleomagnetism 14 18 Southwestern Part of the Japan Sea - of the 13 6

Osaka Group, Southwest Japan Boundary in the 14 27 to the Origin of the Japan Sea - Approach 1 77Prefecture, West Japan Central Yamaguchi 14 36 the Central Part of the Japan Sea During GH78-2 15 53

in Toyama Prefecture, Japan the Yatsuo Area 14 42 M. Torii, When Was the Japan Sea Opened?: and 11 59Peninsula in Northeast Japan for the 14 46 Back-Arc Spreading of the Japan Sea and Its 10 80

Kyushu, Southwest Japan Amakusa-Shinojima, 14 52 from the Inland Sea, Japan (Seto Naikai) I 11 1in Southern Kyushu, Japan Flow Occurring 1 47 Core from the Inland Sea, Japan (Seto Naikai) II: A 11 10

of Boso Peninsula, Chiba, Japan in Southern Part 14 96 Matsushima Bay, Northeast Japan and Its Implication 15 47Sea Plate and Northeast Japan the Philippine 15 35 and Adjacent Areas, Japan, and Its Tectonic 14 24Osaka Group, Southwest Japan in Pleistocene 15 4 Convergence of Southwest Japan and Plate 11 61

Area, Akita Prefecture, Japan K'1roko Mining 15 41 Rotation of Southwest Japan at Middle Miocene 10 77the Rotation of Northeast Japan to the Time of 15 47 and X-Ray Analyses of Japanese Iron Sands 4 5

West Akiyoshi Plateau, Japan Collected from 16 33 from History of the Japanese Islands Inferred 10 93Takadate Area, Northeast Japan in Yanagawa and 16 51 25,000 Chart over the Japanese Islands for 15 23Northeast and Southwest Japan Area between 1 92 Core M. Joshima, Double Jaramillo Eevent in the 10 38

of Nishinoshima-Shinto, Japan from the Lava Flow 2 1 in Sangiran, Central Java Sediments 15 31Prefecture, West Japan in Yamaguchi 2 32 Eevent in the Core M. Joshima, Double Jaramillo 10 38

Hills, Southwestern Japan Sennan and Senpoku 2 34 Ono, and Ujike, M. Joshima, K. Shibata, K. 5 65Kyushu Island, West Japan from Northern 2 38 Oceanic Basalts M. J oshima, Magnetization of 1 9Basalts in Southwest Japan to Some Alkaline 3 1 M. Ozima and M. Joshima, Rock Magnetic 1 I

of Nishinoshima-Shinto, Japan in the Lava Flow 3 17 and Titanomaghemite M. Joshima, Titanomagnetite 3 5Prefecture, West Japan Yamaguchi 3 51 Secular T. Yamazaki, M. Joshima, and Y. Saito, 10 23Prefecture, West Japan Yamaguchi 3 52 Ozima and E.C. Alexander, Jr., Rare Gas M. 3 91

Greenstoness in Central Japan of Paleozoic 3 76 Ozima and E.C. Alexander, Jr., Some Comments on M. 3 100Tuff, Nagano Prefecture, Japan of Shiga Welded 3 79 Paleomagnetism of the San Juan Volcanic Field, 1 71

from the Oki-Dogo Island, Japan Ultramafic Rocks 3 85 Origin of NRM of San Juan Volcanic Rocks from 2 20Prefecture, West Japan End of Yamaguchi 4 106 Total and H. Doi, Abrupt Jump in the Magnetic 16 1

Northern Kyushu Island, Japan Saga Prefecture, 4 116 Paleomagnetic Study of Jurassic Sedimentary and 10 120and Central Honshu, Japan Southeast Hokkaido 4 14 Sawadani Greenstones in Jurassic Subduction of 11 68

Prefecture, West Japan. Central Yamaguchi 4 36 Report of M. Hyodo and K. Yaskawa, Preliminary 12 ISouthern Kyushu Island, Japan Kagoshima, 4 72 the Late 1. Kaneoka, °K_Ar Age Determination of 9 ·111

Tephra, Ina, Central Japan Recorded in Ontake 4 81 Region, Central Japan - K-Ar Age Studies of 6 100of Lake Biwa, Central Japan on the West Coast 5 55 Rocks Paleomagnetism and K-Ar Age of Cretaceous 8 46

Part of Mie Prefecture, Japan in the Northern 5 69 Tuff, O. Matsubayashi, K-Ar Age of Shiga Welded 3 79the Past 30,000 Years in Japan During 5 95 Ujike, Paleomagnetism and K-Ar Age of the Volcanic 5 65

Ryukyu, Southern Japan from Okinawa-Jima, 6 126 Island, Variation and K-Ar Ages in Eastef 15 25Paleosecular Variation in Japan and the Holocene 6 18 Paleomagnetism and K-Ar Ages in Hiba-oa 14 75Discovered at Shibutami, Japan Brunhes Epoch 6 38 Paleomagnetism and K-Ar Ages of Himeji 2 45

Volcanoes, Central Japan in the Yatsugatake 6 46 K. Saito and M. Ozima, K-Ar Ages of Six DSDP Leg 1 98of Lake Biwa, Central Japan on the East Coast 6 48 Kikawa, and H. Kinoshita, K-Ar Ages of Volcanic E. 10 50

Volcanics in Southwest Japan Miocene Muro 6 52 from Paleomagnetism and K-Ar Dating Inferred 16 49Kasa-Yama, Yamaguchi, Japan Basalt from 6 59 K. Fujioka, and H. Sakai, K-Ar,40 Ar-39 Ar Age and 13 48

Tephra Sediments in Japan Late Pleistocene 6 78 J.Y. Oh, T. Hirasawa, K.D. Min, and S. 8 46from Itinomegata, Japan Inclusious 6 97 Morinaga, F. Y.Otofuji, K.H. Kim, H. Inokuchi, H. 12 51

Izu Peninsula, Central Japan Part of the 8 1 Yaskawa, H. Morinaga, K.S. Morinaga, and K. 12 6District, Hokkaido, Japan in the Tokachi 8 106 Remanent H. Ito, K.Tokieda, and Y. Notsu, 9 24

from Okutango Peninsula, Japan Volcanic Rocks 8 22 from Kuro-Shima Island, Kagoshima Prefecture 5 65Chugoku, Southwest Japan Rocks in Eastern 8 40 Lava at Sakura-jima, Kagoshima, Southern 4 72

Tectonic Zone, Southwest Japan in Kurosegawa 8 53 K. H. Morinaga, M. Kamino, H. Inokuchi, and 14Northwest Izu Peninsula, Japan Adjacent Areas, 9 17 Remanent H. Kanaya and K. Noritomi, 2 50

Prefecture, Southwest Japan Complex, Yamaguchi 9 24 M. Ozima, and 1. Kaneoka, A Preliminary 2 62Yamaguchi Prefecture, Japan Northeastern 9 33 the Occurrence of 1. Kaneoka, An Evidence for 5 81

Westcentral Kyushu, West Japan Amakusa Islands, 9 36 H. Kinoshita, K-Ar 1. Kaneoka, E. Kikawa, and 10 50Prefecture, West Japan City, Yamaguchi 9 49 Zashu, and S. 1. Kaneoka, H. Mehnert, S. 6 100

Massif, Northeast Japan in the Kitakami 9 56 Takigami, K. Fujioka, I. Kaneoka, K. Notsu, Y. 13 18Shimane Prefectures, West Japan from Yamaguchi and 9 61 Determination of the 1. Kaneoka, K-Ar Age 9 III

Masuda City, West Japan District, 9 96 Yanagisawa,40Ar-39Ar 1. Kaneoka, M. Ozima, and M. 5 84Motion of Southwest Japan - for Rotational 10 69 B.J.G. Upton, Noble 1. Kaneoka, N. Takaoka, and 11 107

Rotation of Southwest Japan - - Clockwise 9 41 K. Aoki, Possible 1. Kaneoka, N. Takaoka, and 12 89Dike Swarm, Central Japan - An Estimation of 8 28 Constraints on the 1. Kaneoka, Noble Gas 8 94

Dike Swarm, Northeast Japan - An Estimation of 8 17 Systematics in the 1. Kaneoka, Noble Gas 14 105Rotation of Southwest Japan - Fan Shape 13 6 Isotopes and Mass 1. Kaneoka, Rare Gas 6 79

of Magna Region, Central Japan - K-Ar Age Studies 6 100 Takahashi, Rb, Sr and I. Kaneoka, S. Zashu, and E. 3 85Magna and Adjacent Areas, Japan - Present Status 15 39 Argon-40/Argon-36 1. Kaneoka, The 1 106

of Secular Variation in Japan during the Last 6 72 40Ar/39Ar Analyses of I. Kaneoka and K. Aoki, 4 1:10the Eastern Part of the Japan Basin in 15 50 Isotope S. Zashu, 1. Kaneoka, and K. Aoki, Sr 6 97

Borders of Northeast Japan Block and the 15 56 40Ar-39Ar Age Studies I. Kaneoka and M. Yuasa, 15 53Koto Rhyolites, Southwest Japan (II) Cretaceous 14 59 Excess .l29Xe and High I. Kaneoka and N. Takaoka, 4 139

Area of Southwest Japan, Inferred from 12 44 Rare Gas Isotopes in I. Kaneoka and N. Takaoka, 6 88

76

Paleomagnetic Study ofin Olivine Phenocrysts of

Remanent Magnetzation ofof Holocene Basalt from

of Holocene Basalt atby Sediments in Lake

Hyodo, H. Inokuchi, H.Morinaga, F. Murata, H.

M, Yoshida, and Y.J. Nishida, and T.

S. Sasajima, I.Size T. Yamazaki and 1.

H. Tanaka, and T.Shibuya, A. Hayashida,!.

Note on Y. Otofuji, I.Note on the 1.Origin of Y. Otofuji, 1.Suspension Method: I.

Y. Itoh, M. Araki,!.Mehnert, S. Zashu, and S.

H. Domen, Professor Naotoin Lake Biwa and the N.of K. Ikeguchi, and N.

T. Nakajima and N.Hirooka, and K. N.Tokieda, and K. N.Yaskawa, M. Torii, N.Detailed T. Sueishi, N.Magnetic T. Sueishi, N.Progress T. Sato, N.Area of Baragoi, Northern

Phonolite from NorthernRocks in Malawi and

Coastal Area of theKinoshita, E.the Fudeshima Dike E.Kinoshita, and T. E.K-Ar Ages 1. Kaneoka, E.Paleomagnetism of the E.

J. Matsuda, K. Notsu, T.the Reconstructed Ancient

Y. Otofuji, K.H.Magnetic Properties of

Magnetism of KoffyfonteinNodules in South African

in South Africanand Fission-Track Ages of

Domen, H. Muneoka, and M.for Automatically Solving

the Central Ryukyu Arc ­of Instantaneous Plate

Sediments inof the Ocean H.

E. Kikawa, and H.N. Morikawa, and H.

Kikawa, M. Koyama, and H.of the E. Kikawa and H.and T. Nagao, Crustal H.

Y. Hamano, K. Heki, H.Fujisawa, H.Magnetic Anomaly, H.

T. Fujiwara, S. Ogura, H.Paleomagnetic Results H.E. Kikawa, T. Akimoto, H.Paleomagnetism of H.

the Miyako Group in theof Hokkaido Island and

Rocks in the SouthTilting Movements of

M. Koyama and H.Rocks, Study of the

Sueishi, N. Kawai, and K.S. Tonouchi and K.

Sueishi, N. Kawai, and K.T. Sato, N. Kawai, and K.

Analysis T. Sato and K.T. Ishii, K.

K. Hirooka, and K.

"Kanto Loam" the Late 4 88Kapuho Lava and Ratios 4 139Karatsu Cenozoic Basalt, 4 116Kasa-Yama, Yamaguchi, 6 59Kasa.Yama, Yamaguchi 5 47Kasumigaura Recorded 10 23Katao, H. Morinaga, M 14 75Katao, and I<. Yaskawa, A 12 51Katsui, On the Nature of 14 12Katsura, Impure 3 1Katsura, J. Nishida, and 6 130Katsura, Magnetic Grain 15 7Katsura Magnetic 4 1Katsura, S. Yoshida, T. 10 33Katsura, and S. Sasajima, 6 40Katsura and S. Sasajima, 8 67Katsura, and S. Sasajima, 8 61Katsura and S. Yoshida, 11 80Katsura, and T. Danhara, 15 4Kawachi, Pleistocene H. 6 100Kawai: Obituary 6 1Kawai, Organic Elements 3 106Kawai, Remanent Magnetism 2 28Kawai, Secular 1 34Kawai, T. Nakajima, K. 1 53Kawai, T. Nakajima, K. 3 110Kawai, T. Nakajima, K. 3 24Kawai, and K. Kobayashi, 4 99Kawai, and K. Kobayashi, 4 29Kawai, and K. Kobayashi, 4 95Kenya in the Western 12 59Kenya of the Miocene 8 34Kenya, Africa 6 75Kii Peninsula Western 11 55Kikawa, M. Koyama, and H. 14 24Kikawa, Paleomagnetism of 11 26Kikawa, T. Akimoto, H. 9 17Kikawa, and H. Kinoshita, 10 50Kikawa and H. Kinoshita, 11 31Kikukawa, and K. Yaskawa, 8 100Kiln Magnetism of 2 28Kim, H. Inokuchi, H. 12 51Kimberlite S. Akimoto, 2 2Kimberlite Remanent 3 75Kimberlites Megacryst 12 89Kimberlites Peridotites 4 130Kimbo Volcano, Southwest 11 21Kimura, The Natural H. 3 52Kinematic Dynamo Problems 16 8Kinematic History of the 16 47Kinematics by Using VLBI 11 120Kinki and Tokai District 3 41Kinoshit Paleomagnetism 5 111Kinoshita, K-Ar Ages of 10 50Kinoshita, Paleomagnetic 10 120Kinoshita, Paleomagnetism 14 24Kinoshita, Paleomagnetism 11 31Kinoshita, R. Morijiri, 14 96Kinoshita, Y. Onuki, A. 9 66Kinoshita and H. 1 26Kinoshita and N. Matsuda, 14 95Kinoshita, and R. 16 4Kinoshita and T, Akimoto, 14 23Kinoshita, and T. Furuta, 9 17Kinoshita and T. Furuta, 14 66Kitakami Massif, of 9 56Kitakami Mountains 2 54Kitakami Mountains, N.E. 10 85Kitakami Mountains and 6 113Kitazato, Paleomagnetic 15 35Ko-Yama Metamorphic 12 77Kobayashi, Detailed T. 4 99Kobayashi, Magnetic 6 107Kobayashi, Magnetic T. 4 29Kobayashi, Progress 4 95Kobayashi, Spectral 6 16Kobayashi, T. Furuta, and 9 106Kobayashi, The Nakajima, 1 53

the T. Sato and K.Mizutani, Expression K.

Age-Determination of theof the Plio-Pleistocene

Epoch Boundary in theMagnetizations Found K.Magnetratigraphic K.

Remanent Magnetism ofM. Torii, and K.

Kono, M. Koyanagi, and S.and Nonmatine Clays near

Paleomagnetism ofM.Miki,S.

Themal H. Tanaka and M.Paleointensity M.

H. Tanaka and M.Properties of a M.ARM in a Basalt due M.for Automatically M.

N. Ueno and M.Paleointensities in M.

A. Yamamoto, and M.K. Heki, Y. Hamano, M.

Yamaguchi, and Y. M.Kokubun, A Ring-Core M.Wadatsumi, M.Circular Symmetric M.

M. Yanagisawa and M.Onuki, M.Coils for AF M.San H. Tanaka and M.

T. Tosha and M.Heki, Y. Hamano, and M.Heki, Y. Hamano, and M.

Paleointensity M.the San H. Tanaka and M.Paleointensity M.Dynamo and M.Analysis of the M.Paleomagnetic M.in the Spherical M.Spherical Harmonic M.Spherical Harmonic - . M.Hamano, K. Heki, H. M.Yamamoto, Mountain M.Nishitani, and T. M.Analysis of the M.Influence of Partial M.Rikitake Two-Disk M.Paleointensity M.Magnetic Properties M.

K. Heki, Y. Hamano, M.Horiguchi, H. Tanaka, M.

Granites in SouthSupergroup in South

Japan Relative to SouthRocks in Southern Part ofof Cretaceous Rocks from

S. Mukoyama, and T.of the Late Cretaceous

Japan Pole from thefrom the Late Cretaceous

Magnetization of (heEvidence for M.Studies in the South M.the Cenozoic Deposits M.

E. Kikawa, M.Paleomagnetic M.A Ring-Core M. Kono, M.

K. Suwa, H. Ito, and S.Tokieda, K. Suwa, and S.

H. Murayama, Y.Y. Liu, T.the Volcanic Rocks fromMetallogenetic Epoch of

Sequence of the FurutobeSouthwest System in

C. Itota, H. Morinaga, M.on Baked Earths in

77

Kobayashi, Variation ofKobayashi and S.Kobe Sedimentary GroupKobiwako Group on theKobiwako Group on theKodama, ReverseKodama and T. Baba, AKoffyfontein KimberliteKoga, CounterclockwiseKokubun, A Ring-Core M.Komyoike, Osaka MarineKomyoike Volcanic AshKondo, and Y. Otofuji,Kono, A Furnace forKono, An Attempt ofKono, Analysis of theKono, Changes in MagneticKono, Changes in TRM andKono, Computer AlgebraKono, Determination ofKono, GeomagneticKono, Gravity AnomalyKono, K. Nomura, N.Kono, M. Hoshi, K.Kono, M. Koyanagi, and S.Kono, M. Ozima, and ICKono, Magnetic Field in aKono, Mean IonosphericKono, N. Ueno, and Y.Kono, Optimum Design ofKono, Origin of NRM ofKono, PaleointensityKono, Paleomagnetic StudyKono, Paleomagnetic StudyKono, Paleomagnetism andKono, Paleomagnetism ofKono, Reliability ofKono, Rikitake Two-DiskKono, Spherical HarmonicKono,. Statistics ofKono, Uniqueness ProblemKono, Uniqueness of theKono, Uniqueness of theKono, Y. Fukao, Y.Kono, Y. Fukao, and A.Kono, Y. Hamano, T.Kono and H. Tanaka,Kono and H. Tanaka,Kono and M. Hoshi, TheKono and N. Deno,Kono and S. Akimoto,Kono, and T. Ui,Kono, and Y. Hamano, A.Korea of CretaceousKorea - GyeongsangKorea since LateKorean PeninsulKorean Peninsula - AgeKoshimizu, Y. Fujiwara,Koto Rhyolite: NewKoto Rhyolite, SouthwestKoto Rhyolites, SouthwestKoyama Intrusive Complex,Koyama, PaleomagneticKoyama, PaleomagneticKoyama, Paleomagnetism ofKoyama, and H. Kinoshita,Koyama and H. Kitazato,Koyanagi, and S. Kokubun,Kume, Remanent MagnetismKume, Remanent Ito, K.Kuramoto, and K. Yaskawa,Kuro·Shima Island, ofKuroko Deposits of l.heKuroko Mining Area, AkitaKurosegawa Tectonic Zone,Kusakabe, F. Murata, S.Kyoto Prefecture

6 111 59

14 106 185 55

12 3514 52

3, i512 1110 I

3 325 19

16 172 211 88

10 164 18

12 7216 84 731 83

15 6510 12016 2410 I

2 458 89

11 11212 18

6 1462 206 619 72

10 1125 981 il4 22

13 711 1246 1513 1021 1182 919 66

15 736 22

10 93 10

14 973 612 2

10 10512 94

2 598 461 77

12 518 466 49

13 3013 1614 59

9 2410 6115 39

8 114 2415 3510 I

3 756 75

15 155 652 40

15 418 53

16 3811 1

Saga Prefecture, NorthernKagoshima, Southernfrom the WestcentralRocks from Northern

Rocks In Central EasternOccurring in Southern

Amakusa-Shinojima,Islands, Westcentral

S. Sasajima, PreliminaryA. Taira, T. Ui, and

ARM in a Basalt due toModel and Depth

Core Samples fromon the West Coast ofon the East Coast of

Paleomagnetism ofYears Found from the

Organic Elements inRecorded by Sediments in

Collected from HardingMagnetic Properties of

Rocks from Southern SriPrecambrian Rocks of Sri

Translation Y. Otofuji,of Paleomagnetism of Some

the Nohi Rhyolite ofMagnetic Activity of the

Results from theK. Fukuma and M. Torii,

of Igneous Rocks ofto South Korea since

and Chronology of theReversal Recorded in the

Correlation of theof "Kanto Loam" the

Remanent Magnetization ofReconnaissance of Some

Field Reversals duringAge Determination of the

Reversal in theOn the Excursion of thein the Holocene and the

of bu OshimaExtracted from the

Iron Discovered in theof Scottish Devonian

Island Obtained from thefrom the Historical

Volcano from Recent FourPhenocrysts of Kapuho

Kagoshima, of HistoricalNohle Gas Systematics in

of the Old Sommaa Water-Laid Volcanic AshEpisode in a Volcanic Ash

Gas Constraints on theAllan of Dirt Ice

Water-Laid Volcanic AshWater-Laid Volcanic Ash

of a Stalagmite, in PingHirooka, Y. Otofuji, T.V.

Brunhes Chron at Hole 650K-Ar Ages of Six DSDP

Early Measurements onDrilling Project, Cruise

the Change to a SlightlyRocks of Tansen Area,

of Collapse infrom Ridges in the

Volcanic Rocks from theMagnetic Anomaly

on Rare Gas Solubility inand S. Nishimura, The

Adachi, H. Morinaga, Y.Y.Horie, H. Maruyama, Y.Y.Horie, H. Murayama, Y.Y.

Study of "Kantofor Northward Drift and

Kyushu Island, Japan 4 116Kyushu Island, Japan 4 72Kyushu Island, West Japan 10 134Kyushu Island, West Japan 2 38Kyushu Islands Igneous 13 1Kyushu, Japan Flow 1 47Kyushu, Southwest Japan 14 52Kyushu, West Japan 9 36L. Chun, K. Maenaka, and 8 9L. Ocola, Geophysical 9 66Laboratory Heating and 12 72Lag of NRM in Deep-Sea 4 65Lake Biwa Deep Drilling 10 33Lake Biwa, Central Japan 5 55Lake Biwa, Central Japan 6 48Lake Biwa Sediment 3 24Lake Biwa Sediments 1 34Lake Biwa and the Climate 3 106Lake Kasumigaura Japan 10 23Lake in Interior Alaska, 12 6Lamellar Tetrataenite in 12 83Lanka of Some 16 61Lanka in View of Gondwana 14 86Large Northward 14 80Late Cenozoic Basalt 8 9Late Cretaceous Age 12 29Late Cretaceous Koto of 13 30Late Cretaceous Koto 14 59Late Cretaceous 13 16Late Cretaceous to 9 41Late Mesozoic, - A 1 77Late Neogene to Quternary 8 106Late Pleistocene 1 51Late Pleistocene Tephra 6 78Late Pleistocene Volcanic 4 88Late Precambrian Rocks in 6 75Late Precambrian to Early 13 39Late Tertiary 9 27Late Tertiary and K-Ar 9 IIILatest Brunhes Epoch 6 38Latest Pleistocene 4 81Latest Pleistocene from 6 30Lava Flow in 1986 15 1Lava Flow of Minerals 2 1Lava Flow of Native 3 17Lava Flows Magnetism 5 25Lava Flows in Oshima 6 25Lava Flows of Hawaii 4 73Lava Flows of Sakurajima 5 87Lava and Xenolithic 4 139Lava at Sakura-jima, 4 72Lavas and a Dunite Nodule 11 107Lavas of Hakone Volcano 6 82Layer in the Osaka Group 1 65Layer with the Fission 9 13Layered Structure of the 8 94Layers Collected from 11 75Layers in from the 3 41Layers in the Osaka the 2 34Le, South China 15 21Leeuwen, and Hehuwat, K. 5 73(Leg 107, Tyrrhenian the 15 28Leg 17 Samples M.Ozima, 1 98Leg 55 Basalts in the 6 61Leg 58, by Glomar Sea 5 111Less Magnetic Phase in 11 96Lesser Himalaya, Nepal 13 39Limestone Cave by 15 15Line Chain and Their 2 71Line Islands of the 4 122Lineations in the 5 118Liquid Some Comments 3 100List of Fission-Track 9 117I.,iu, G.Z. Fang, ~nd K. 16 57Liu, H. Morinaga, I. 15 21Liu, T. Kuramoto, and K. 15 15Loam" the Late 4 88Local Deformations of the 10 61

Thickness of theSedimentation for YoungDid Magnetization Fix in

Olivine with RelativelyApplicability to High and

Grain Size Effect on thein the Study on the

in Metal Particles ofTagami, Y. Otofuji, Y.

of Pre-Jaramillo K.of Komyoike Volcanic K.Change Ohtained from K.Preliminary K.Preliminary 1. Chun, K.

Sr Isotope Studies ofHemoilmenite in a Cooling

Activity in the FossaJapan in the South FossaLate Short Duration of

Peninsula Inferred fromKinoshita and N. Matsuda,Yaskawa, and H. Inokuchi,

and K. Kobayashi,Crustal Structure and

in Analyses of NRM UsingN. Ishikawa, Anomalous

Chemical and AlternativePliocene of the Earth'sCircular M. Kono,

to High and LowYamazaki and I. Katsura,

Characterization of FineProperties of Y. Hamano,

Paleomagnetic and Rockof Tephras byof Tephras byof Tephras by

the Note on the RemanentChange to a Slightly Less

in the Confirmation of aHayashi, and M. Nedachi,M. Kono and S. Akimoto,

M. Funaki and T. Nagata,H. Tanaka, and T. Katsura

M. Kono, Changes inKatsura, and T. Danhara,

H. Akai, and T. Furuta,Recorded in the Stable

Kawai, and K. Kobayashi,Property of So-called

and M. Joshima, RockJ. Donon, and T. Nagata,

Note on Paleo/RockReport on a Paleo/Rock

Report on Paleo/RockH. Domen, On a Paleo/Rock

Preliminary Report on theArcheological H. Tanaka,

N. Oshiman and H. Tanaka,Hamano and K. Yomogida,

Doi, Abrupt Jump in theMagnetism and Formation

Their Relevance to RockCosta Rica Ridge Rock

Component of Remanentand S. Kume, Remanent

Stability of Remanentand S. Sasajima, On the

and N. Kawai, Remanentof Respective Remanent

Chemical Composition ofby Remanent

RemanentAnomalous Remenent

K. Yaskawa, When DidPumice with Self-ReversedSiliceous Clay RemanentSediments Remanent

Lock-In Zone of 11 8SLoose Sediment Rate of 1 3DLoose Sediments? When 2 ISLow 40Ar/36Ar Ratios in 12 RDLow Magnetic Fields 2. 10 IGLow-Temperature Oxidation 6 12RLower Cretaceous Series 12 3RLunar and Meteorite 1 21Maeda, and S. Sasajima 10 33Maenaka, On the Existence 6 9~

Maenaka, Paleomagnetism 5 ~9

Maenaka, The Polarity 3 41Maenaka and S. Sasajima, 12 3RMaenaka, and S. Sasajima, 8 DMafic and Ultramafic 6 9iMagma and Its Relation to 9 102Magna Region, Central 6 100Magna and Adjacent Areas, 15 3DMagnetic Activity of the 13 30Magnetic Anomalies Boso 16 ~

Magnetic Anomaly, Crustal 14 D5Magnetic Anomaly K. 5 I1RMagnetic Anomaly and 6 lOiMagnetic Anomaly in 14 96Magnetic Dipole Models 9 99Magnetic Direction of a 11 55Magnetic Field Cleaning 6 59Magnetic Field in 3 56Magnetic Field in a 8 89Magnetic Fields 10 16Magnetic Grain Size and 15 iMagnetic Grains in 11 ROMagnetic Hysteresis 6 13iMagnetic Investigation of 9 106Magnetic Measurement (1) 6 107Magnetic Measurement (2) 6 112Magnetic Measurement (3) 6 118Magnetic Measurement of 2 32Magnetic Phase in the 11 96Magnetic Polarity Episode 6 85Magnetic Polarity K. 15 41Magnetic Properties of 2 2Magnetic Properties of 12 83Magnetic Properties of 4 IMagnetic Properties of a 4 18Magnetic Properties of 15 4Magnetic Properties of 6 82Magnetic Remanence of the 6 14Magnetic Stability of N. 4 29"Magnetic Stone" from 9 96Magnetic Structures of 1 1Magnetic Studies of the 14 1Magnetic Study of 14 36Magnetic Study of 5 4iMagnetic Study of the 10 13~

Magnetic Study of the 9 33Magnetic Survey in Niue 6 36Magnetic Surveying of 8 81Magnetic Surveying of an 6 iMagnetic Susceptibility 8 i5Magnetic Total Force at 16 1Magnetism Ridge Rock 14 66Magnetism Zones and 16 16Magnetism and Formation 14 66Magnetism in Moriyama 5 11Magnetism of Koffyfontein 3 i5Magnetism of Scottish 5 2SMagnetism of Y. Otofuji, 5 2iMagnetism of the 2 28Magnetisms of 1 iMagnetite from the Ueno, 13 60Magnetization 16 1Magnetization 4 53Magnetization Caused by 6 S2Magnetization Fix in 2 15Magnetization from the 14 12Magnetization in Deep-Sea 11 8SMagnetization in Wet 8 61

78

M.

on theof

The Distribution ofProcess in the

Oxygen on ThermoremanentBasalt Natural Remanent

on the Natural RemanentDeformation on a Remanent

Ash of Natural RemanentFunaki, Natural RemanentSeamount T. Yamazaki,

On Natural Remanentand K. Noritomi, RemanentRocksShocks on RemanentMeasurement of Remanent

and S. Kume, RemanentBasalts M. Joshima,

of Natural RemanentSize and Viscous RemanentClay and A. Nishimura,

The Natural Remanentto the Changes of

and T. Nakajima, RemanentDepositional RemanentN. Niitsuma, Remanent

Rocks Natural RemanentSoils Natural Remanent

and K. Yaskawa, Remanentand Y. Notsu, Remanent

Ishida, Natural Remanentthe K. Kodama, ReverseYoshida, On the SecondaryFunaki, Natural Remanent

Fluxgate for Spinnerby Means of a Spinner

Controlled AstaticT. Tosha, A New Spinner

An Automatic SpinnerK. Takemura and M. Torii,in Consistency Check of

and T. Tonosaki,Neogene Rocks Y. !toh,

Preliminary Report ofK. Kodama and T. Baba, A

On the Natural RemanentOn the Natural Remanent

Field Correction forPacific: Evidence of

Nishida, Y. Otofuji, T.Late Precambrian Rocks in

Nawakot Complex Rocks,of K.Reversal Recorded in K.

Layered Structure of theTrace Elements from the

Interaction M. Ozima, OnMagnetization of Slumped

of Osaka Group UsingRarotonga, Rurutu, andAges in Hiba-oa Island,

Study of H. Sakai and S.H. Morinaga, I. Horie, H.H. Morinaga, 1. Horie, H.

Rare Gas Isotopes andwith a Quadrupole Type

Group in the Kitakamifrom Ji-no-Ura District,

M. Ozima, On Mantle-CrustMatsuda, On the Y.Shiga Welded Tuff, O.and I. Kaneoka, A O.

Y. Otofuji and T.Otofuji, T. Itaya, and T.

K. N. Isezaki, J.Kikukawa, and K. J.

H. Kinoshita and N.Y. Matsubara and J.

of Y. Otofuji and T.of Y. Otofuji and T.

M. Miki, H. Inokuchi, J.

Magnetization in theMagnetization ofMagnetization of BasaltsMagnetization of CenozoicMagnetization of ReportMagnetization of CuoCoMagnetization of DiluvialMagnetization of DirtMagnetization of ErimoMagnetization ofMagnetization of IbaragiMagnetization of IgneousMagnetization of IzuMagnetization of LateMagnetization of OceanicMagnetization ofMagnetization of PelagicMagnetization of PelagicMagnetization of Kimura,Magnetization of RocksMagnetization of SakiMagnetization of on PostMagnetization of SlumpedMagnetization of SomeMagnetization of SurfaceMagnetization ofMagnetization of theMagnetization of the S.Magnetizations Found fromMagnetizations ObservedMagnetizations of BeaconMagnetometer A Ring-CoreMagnetometer MeasurementMagnetometer A ComputerMagnetometer: PrinciplesMagnetometer with ThermalMagnetosratigraphy of theMagnetostratigraphic DataMagnetostratigraphy andMagnetostratigraphy ofMagnetostratigraphy ofMagnetratigraphic StudyMagnetzation of ColumbiaMagnetzation of KaratsuMagsat Data IonosphericMajor Aeolian OriginMakinouchi, and J.Malawi and Kenya, AfricaMalekhu Area, Central inManabe, Consistency CheckManabe, GeomagneticMantleMantie to the CrustMantle-Crust MaterialMarine Sedimentary RocksMarine and NonmatineMarquesas Ocean: Samoa,Marquesas, French K-ArMaruyama, PaleomagneticMaruyama, and Y. Yaskawa,Maruyama, and Y. Yaskawa,Mass FractionationMass Spectrometer GasesMassif, Northeast JapanMasuda City, West JapanMaterial InteractionMatsubara and J.Matsubayashi, K-Ar Age ofMatsubayashi, M. Ozima,Matsuda, Amount ofMatsuda, Fast Drifting ofMatsuda, H. Inokuchi, andMatsuda, K. Notsu, T.Matsuda, MagneticMatsuda, On theMatsuda, PaleomagnetismMatsuda, PaleomagnetismMatsuda, S. Yamaguchi, N.

15 50 Ozima, Anomalously J.4 61 Ozima, Sr Isotopic J.3 10 Studies of the J.4 106 M Hyodo, H. Inokuchi, J.

10 137 Natural M. Torii, T.6 123 Y. Otofuji, T.4 36 Clockwise M. Miki, T.

11 75 Y. Itoh, M. Torii, and T.14 91 and N. N. Shima, K.

4 72 Otofuji, S. Funahara, J.2 50 M. Ozima and S.1 13 Water in Cytherean S.

15 1 Sedimentary Rocks around6 75 Local Deformations of the1 9 of Pre-Jaramillo Event in3 76 Epoch of Field in the

15 7 Property of an Icelandic12 53 of Beacon Group in3 52 Complex in Wright Valley,9 102 Yanagisawa and M. Kono,6 102 on the NRM Measurement by6 40 of Southwestern Japan4 44 of Tephras by Magnetic

16 61 of Tephras by Magnetic15 11 of Tephras by Magnetic14 7 Domen, A Note on the NRM9 24 Nishitani and S. Sasaki,8 34 Takeuchi, Paleomagnetic

12 35 and K. Yaskawa, Shipboard14 68 on the Remanent Magnetic

9 80 T. Tosha, PaleomagneticlOIS. Sasajima Paleomagnetic

5 40 and H. Fujisawa,6 143 Several Archeomagnetic6 22 M. Kono, Paleointensity

16 24 M. Ozima, Transport5 69 H. Sakai, NRM Acquisition3 47 South Ratios in Olivine8 106 Kawachi, 1. Kaneoka, H.

14 42 on Paleomagnetism in the3 36 High Y. Hamano, The

14 52 to South Korea since Late4 114 from the Paleozoic and4 116 Nickel Concentration in

11 112 of the Duration of the12 53 Hirooka and 1. Hattori,

3 36 Study of the Ko-Yama6 i5 Magnetic Study of the

14 68 in Toluca Iron3 47 of the Bocaiuva Iron1 51 Particles of Lunar and8 94 Radiometric Ages of4 155 Anisotropy of Chondritic2 76 Ages of Some Yamato4 44 Susceptibility3 32 Crystals by the Flux8 100 by a Modified Thelliers'

14 75 Using a Single Heating11 68 by the Thellier16 33 S. Yoshida, Suspension15 21 of the Thelliers'6 79 of the Thelliers'2 62 Field of Paleointensity9 56 Containing Spinel9 96 Dating of Calcareous2 76 T. Nishitani, Electron6 1 (87Sr/86Sr) Ratio from3 79 Remanent Direction of the2 62 Rocks In Directions from

13 6 Torii, Paleomagnetism of16 49 of Southwest Japan at

6 30 in the Northern Part of8 100 Matsuda, S. M.

14 95 Yaskawa, and H. H.6 1 Otofuji, M.9 41 Otofuji, Clockwise M.

10 69 Inokuchi, K. Yaskawa, T.15 25 Paleomagnetic Study M.

79

Matsuda, S. Zashu, and M. 1 102Matsuda, S. Zashu, and M. 2 GOMatsuda, Sr Isotopic 4 1nMatsuda and K. Yaskawa 14 75Matsuda, and S. Ishida, 8:11Matsuda, and S. Nohda, 11 ~ f,Matsuda, and Y., Otofuji, 14 38Matsuda, the Nohi on 12 29Matsumoto, M. Furukawa, 15 50Matsuo, F. Murata, T. Y. 14 78Matsuo, Implication of 4 Ui 1Matsuo, On Deficiency of 2 79Matsushima Bay, Northeast 15 HMatsuzaki Area, Izu and 10 GJMatuyama Epoch Existence 6 9~

Matuyama Geomagnetic 1 53Matuyama Reversed Rock 8 59McMurdo Sound, Antarctica 9 80McMurdo Sound, Antarctica 9 88Mean Ionospheric Field 11 112Means of a Spinner Note 5 ~o

Measured and Compiled in 6 10Measurement (1) 6 107Measurement (2) 6 112Measurement (3) 6 118Measurement by Means of a 5 40Measurement of Remanent 15 1Measurement of Several 11 38Measurement of Three 6 30Measurement of the Note 2 32Measurement of the Miyako 9 56Measurements of Deep and 10 33Measurements of 1 2GMeasurements on Baked 11 1Measurements on Leg 55 6 GlMechanism of Trace 4 155Mechanisms for Snow and 13 55Megacryst Nodules in 12 89Mehnert, S. Zashu, and S. 6 100Melanesia Basin Report 4 95Melting of Pure Iron at 2 86Mesozoic, - A Relative 1 77Mesozoic Rocks of the 15 64Metal Particles of Lunar 1 21Metallogenetic Epoch of 2 40Metamorphic Effects on 3 76Metamorphic Rocks, 12 77Metamorphic Rocks from 9 33Meteorite Tetrataenite 12 83Meteorite Studies 14 1Meteorite Samples Metal 1 21Meteorites F.A. Podosek, 6 94Meteorites 8 75Meteorites from 5 8.1Meter High-Temperature 16 20Method Olivine Single 3 18Method Determination 3 61Method Determination 4 10·1Method Determined 5 18Method: Characterization 11 80Method of Paleointensity 10 9Method of Paleointensity 10 16Methods Using Alternating 4 n(MgAI204) 4Microfossils in Deep-Sea 8 85Microprobe and 11 91Mid-Atlantic Ridge Basalt 1 102Middle Miocene Granite 13 8Middle Miocene Igneous 13 1Middle Miocene Muro M. 6 52Middle Miocene Time 10 77Mie Prefecture, Japan 5 G9Miki, H. Inokuchi, J. 15 25Miki, N. Isezaki, K. 5 118Miki, S. I(ondo, and Y. 16 HMiki, T. Matsuda, and y., 14 38Miki, and M. Ikeya, H. 13 51Miki and Y. Otofuji, 16 4·1

T.

and

H.

Report

4 10,14 724 1144 l](j

10 1379 nn

10 13·13 523 5]

12 :'116 3R14 7815 :,D15 15

6 525 344 766 27

10 R:,13 5!"i10 1384 3n5 409 9n4 652 :'42 203 79

14 9612 8314 1

1 131 21

11 411 10

6 109 13

15 231 533 1103 242 28

10 536 1026 52

12 5n1 348 224 81

16 16 866 1

14 783 172 283 244 106

10 1374 36

11 754 723 763 52

16 6115 118 349 804 1144 116

14 1214 6815 4112 6614 3110 10514 4213 12

8 106

H.Effects

Muneoka, Examples of theMuneoka, On NaturalMuneoka, On the NaturalMuneoka, On the NaturalMuneoka, PreliminaryMuneoka and H. Domen,Muneoka and H. Domen,Muneoka, and M. Kimura,Muneoka, and T. Yokoyama,Murata, H. Katao, and K.Murata, S. Yamaguchi, N.Murata, T. Nishiyama, X.Murata, and X. Zheng,Murayama, Y.Y. Liu, T.Muro Volcanics inMuroi, Error AnglesMuroi and K. Yaskawa,Myoko Volcano Two DatedN.E. Honshu, Japan theNRM AcquisitionNRM Direction of H.NRM Intensity of SedimentNRM Measurement by MeansNRM Using Magnetic DipoleNRM in Deep·Sea SedimentsNRM of CretaceousNRM of San Juan VolcanicNagano Prefecture, JapanNagao, Crustal StructureNagata, MagneticNagata, Magnetic StudiesNagata, Notes onNagata, The VolumetricNaikai) I from theNaikai) II: A SecularNakajima, ArcheomagnetismNakajima, Blake PolarityNakajima, IsomagneticNakajima, K. Hirooka, andNakajima, K. Tokieda, andNakajima, K. Yaskawa, M.Nakajima, M. Torii, N.Nakajima PaleomagneticNakajima, RemanentNakajima and K. Hirooka,Nakajima and M. Torii,Nakajima and N. Kawai,Nakajima and Y. Morimoto,Nakaya, On the ExcursionNakayama, and H. Doi,Nakazawa, The Origin ofNaoto Kawai: ObituaryNarrow Zone Along theNative Iron Discovered inNatsuhara, K. Yaskawa, M.Natsuhara, PaleomagnetismNatural Remanent andNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural RemanentNatural Remanent DomenNatural Remanent DomenNature of Remanence inNawakot Complex Rocks,Nedachi, MagneticNedachi, OpaqueNedachi, Y.Vrashima, KNeogene Ocros Dike SwarmNeogene Rocks around theNeogene Rocks in theNeogene to Quternary

H. Domen and H.RemanenH. Domen and H.RemanenH. Domen and H.RemanenH. Domen and H.Report H. Domen and H.Errors in Analyses of H.Progress Report on H.The Natural H. Domen, H.Progress H. Domen, H.Inokuchi, H. Morinaga, F.

Morinaga, M. Kusakabe, F.Funahara, J. Matsuo, F.

Y. Inoue, S. Funahara, F.H. Morinaga, 1. Horie, H.

of Middle Miocenewithin a Specimen 1.Paleomagnetism of S.

Pyroclastic Flows of theSouth Kitakami Mountains,

M. Funaki and H. Sakai,Domen, A Short Note on an

Attempt to Normalize theH. Domen, A Note on the

Errors in Analyses ofModel and Depth Lag of

Deduced from theand M. Kono, Origin of

Age of Shiga Welded Tuff,and R. Morijiri, and T.

M. Funaki and T.Taguchi, J. Donon, and T.Integrated Effect of T.

N. Sugiura and T.Inland Sea, Japan (SetoInland Sea, Japan (Seto

of H. Shibuya and T.Episode in a Volcanic T.Chart over the T.K N. Kawai, T.K. Hirooka, N. Kawai, T.Torii, and N. Kawai, T.Natsuhara, K T.

H. Sakai,.and T.H. Sakai and T.

Anomalous Remenent T.Paleomagnetism of T.Secular Geomagnetic T.Paleomagnetism and T.of T. Yokoyama, and S.

S. Sakai, H. Oda, T.Rate M. Ozima and K.

H. Domen, ProfessorDeformation of the

the Lava Flow K. Momose,T. Nakajima, M. Torii, N.

Yaskawa, M. Torii, and N.H. Muneoka, Classified

Preliminary Report on theon the Stability of

Magnetization M. Funaki,Domen and H. Muneoka, On

on the Intensity ofand M. Kimura, Theand P.W. Vitanage,

and K. Yaskawa, AnomalousMatsuda, and S. Ishida,

M. Funaki,and H. Muneoka, On theand H. Muneoka, On the

and Y. Katsui, On theMalekhu Observed inVeno, K. Hayashi, and M.

H. Veno and M.Ibaragi, and H. Veno, M.

T. Vi, Paleomagnetism ofMagnetostratigraphy of

Study of Cretaceous andChronology of the Late

Min, and S. Sasajima, 8 46Mineralogy and H. Veno 12 66Minerals Extracted from 2 1Minerals in Hydrothermal 16 16Minerals in Pyroclastic 4 14Minerals in the Deep·Sea 4 9Mining Area, Akita 15 41Mining Area, Japan 13 60Miocene - An Estimation 8 28Miocene Age from the Go 9 41Miocene Andesite Dyke 11 55Miocene Counter-Clockwise 11 45Miocene Granite from the 13 8Miocene Granitic Rock in 6 58Miocene Igneous Rocks In 13 1Miocene Muro Volcanics in 6 52Miocene Phonolite from 8 34Miocene Rocks 12 44Miocene Rocks in the M. 12 59Miocene Sedimentary Rocks 15 47Miocene Series 12 33Miocene Time Rotation of 10 77Miocene Volcanic Rocks 8 22Miocene: Yatsuo Area 11 51Miura Peninsula Results 9 4Miyachi, and 1. Hirano, 11 21Miyako Group in the 9 56Miyako-Jima Island in the 16 44Mizutani, Expression of 1 59Model Earth-Atmosphere 3 91Model and Depth Lag of 4 65Models in Analyses of 9 99Modified Thelliers' 3 61Module Collected from off 13 51Momose, Native Iron 3 17Momose, Stability of 5 25Momose, Thermomagnetic 4 8Momose, Thermomagnetic 2 1Momose and S. Inagaki, On 1 7Morijiri, Study of 16 4Morijiri, and T. Nagao, 14 96Morikawa, and H. Hamano, 10 120Morimoto, Paleomagnetism 8 22Morinaga, Cretaceous 10 85Morinaga, F. Murata, H. 12 51Morinaga, H. Imamura, H. 15 11Morinaga, H. Inokuchi, K 13 51Morinaga, H. Inokuchi, K 14 40Morinaga, H. Inokuchi, 11 16Morinaga, H. Inokuchi, 14 18Morinaga, 1. Horie, H. 16 33Morinaga, 1. Horie, H. 15 21Morinaga, I. Horie, H. 15 15Morinaga, K.S. Morinaga, 12 6Morinaga, M Hyodo, H. 14 75Morinaga, M. Kamino, H. 14 7Morinaga, M. Kusakabe, F. 16 38Morinaga, Y.Y. Liu, G.Z. 16 57Morinaga, and K. Yaskawa, 6 68Morinaga, and K. Yaskawa, 12 6Moriyama Deep Drilling 5 11Motion in the Core of 2 84Motion of Southwest Japan 10 69Motion of Southwest Japan 12 33Mount St. Helens, U.S.A. 8 57Mountain Building in the 15 73Mountains Deduced from 2 54Mountains, N.E. Honshu, 10 85Mountains, West 13 35Mountains and Oshima 6 113Movements of Kitakami 6 113Mugearite Dredged from 3 81Mukoyama, and T. 6 49Muneoka, A Brief Note on 2 32Muneoka, A Paleomagnetic 9 36Muneoka, A Progress 2 38Muneoka, A Progress 8 38Muneoka, Classified 4 106

Oh, T. Hirasawa, K.D.and M. Nedachi, OpaqueCurves of Ferromagnetic

H. Ueno, OpaqueN. Aida, Ferromagnetic

Inokuchi, Ferromagneticof the Furutobe Kuroko

Diorite Bodies, Chichibuof Paleointensity in

of Late Cretaceous toMagnetic Direction of a

Evidence for theDirection of the Middle

Notsu, Paleomagnetism ofDirections from Middle

Paleomagnetism of MiddleMagnetization of the

Study of Oligocene toTorii, Paleomagnetism of

around Paleomagnetism ofof the Setouchi

Southwest Japan at MiddleFission Track Age of the

of Hokuriku District inof the Ofuna Formation,

M. Takai, M.Measurement of the

Paleomagnetic Study onK Kobayashi and S.

EvolutionNRM Zone-Magnetization

NRM Using Magnetic DipoleDetermination by a

New of a PhosphoriteDiscovered in the KRemanent Magnetism ofKAnalysis of H.Curves of KDiscrimination of K

H. Kinoshita, and R.Crustal H. Kinoshita, R.

M. Kono, K. Nomura, N.and T. Nakajima and Y.

Y. Fujiwara and A.KH. Kim, H. Inokuchi, H.

Inokuchi, and K H.Yaskawa, T. Miki, and H.Yaskawa, C. Itoya, H.and K. Yaskawa, H.and K. Yaskawa, H.Maruyama, and Y. H.Maruyama, Y.Y. Liu, H.Murayama, Y.Y. Liu, H.and K. Yaskawa, H.Inokuchi, H. Katao, H.Inokuchi, and K. H.Murata, S. C. Itota, H.Fang, and Y. Adachi, H.

H. Inokuchi, H.H. Morinaga, KS.

of Remanent Magnetism inParameters of TurbulentEvidence for Rotational

Timing of RotationalVolcanic Ash Erupted fromFukao, and A. Yamamoto,the Island and Kitakami

in the South KitakamiRocks from the Ellsworth

Movements of Kitakamito Possible Tilting

Suiko Isochron Age of aY. Fujiwara, S.

the H. Domen and H.Study of H. Domen and H.Report H. Domon and H.Report H. Domen and H.Natural H. Domen and H.

80

and

IzuEast

Area, Lesser Himalaya,Malekhu Area, Central

Kinematics by Using VLBIby Thermomagnetic andMagnetization from the

Volumetric Histogram ofM. Ozima, Growth of

Rotation and N.Magnetization of N.Zone-Magnetization N.

K. Yamaguchi, and Y.S. Sasajima and J.

T. Makinouchi, and J.Paleomagnetic Study J.On the Self-Reversal J.

I. Katsura, J.Impure S. Sasajima, J.Otofuji, S. Sasajima, S.of T. Yamazaki and A.of H. Ito and S.

Y. Amano and S.History T. Tagami and S.

Otofuji, S. Sasajima, S.Hirooka, S. Sasajima, S.

from the Lava Flow ofin the Lava Flow of

Microprobe and T.Effect on the T.T. Katsura Magnetic T.Basalt Samples from T.Shimamura, T.Measurement of T.Paleomagnetic T.AM. Kono, Y. Hamano, T.and H. Ito, Y.

J. Matsuo, F. Murata, T.on the Magnetic Survey in

- Classification ofthe Layered I. Kaneoka,Lavas and B.J.G. Upton,the Earth's I. Kaneoka,

Determination ofin Lavas and a DuniteAnalyses of Phlogopite

in Hawaiian Ultramaficin Olivine Megacryst

T. Matsuda, and S.and T. Matsuda, the

M. Kono, and Y. Hamano,Y. Hamano, M. Kono, K.Group Using Marine and

H. Kanaya and K.Episode in the Brunhes

Reversals in BrunhesH. Inokuchi, Attempt to

Group in Datong Province,Rotation of

for the Peninsula inPhilippine Sea Plate andTime of the Rotation of

and Takadate Area,in the Kitakami Massif,

the Shimokura Dike Swarm,and Southern Borders of

around Matsushima Bay,the Boundary Area between

Alteration Zone,Cenozoic Deposits in the

Rocks from Susa District,Metamorphic Rocks,

and Volcanic Rocks inand Volcanic Rocks in

Western Area of Baragoi,Miocene Phonolite fromBasalt, Saga Prefecture,on Cenozoic Rocks from

Age Group in thePotsherds near Cajamarca,

Nepal Rocks of Tansen 13 39Nepal Complex Rocks, 14 68Network Plate 11 120Neutron Activation Flow 6 49Nevado Del Ruiz, Colombia 14 12Nickel Concentration in 1 21Nickel Olivine Single 3 18Niitsuma, Galactic 1 130Niitsuma, Remanent 4 44Niitsuma, 4 65Nishi, An Automatic 16 24Nishida, On the 2 5Nishida, Preliminary 3 36Nishida and S. Ishida, 3 32Nishida and S. Sasajima, 2 10Nishida, and S. Sasajima, 6 130Nishida, and T. Katsura, 3 1Nishimura, K. Hirooka, Y. 5 73Nishimura, Magnetization 12 53Nishimura, Short Duration 13 30Nishimura, The List of 9 117Nishimura, Thermal 11 103Nishimura, and F. Y. 6 69Nishimura, and K. 6 90Nishinoshima-Shinto, 2 INishinoshima-Shinto, 3 17Nishitani, Electron 11 91Nishitani, Grain Size 6 128Nishitani, H. Tanaka, and 4 1Nishitani, Inclination of. 10 129Nishitani and C. 16 30Nishitani and S. Sasaki, 15 1Nishitani and S. Tanoue, 14 46Nishitani, and T. Tosha, 6 22Nishiyama, A. Tokuyama, 11 63Nishiyama, X. Zheng, and 14 78Niue Island Report 6 36Noble Gas Components 14 105Noble Gas Constraints on 8 94Noble Gas Systematics in 11 107Noble Gas Systematics in 14 105Noble Gases with a 2 62Nodule from Reunion and 11 107Nodules and 40Ar/39Ar 4 130Nodules and Volcanic 6 88Nodules in South African 12 89Nohda, Paleomagnetic 11 45Nohi Rhyolite of Late 12 29Noise and Stability of 12 94Nomura, N. Morikawa, and 10 120Nonmatine Clays near 3 32Noritomi, Remanent 2 50Normal Epoch: A Polarity 6 85Normal Polarity Epoch 1 44Normalize the NRM 4 39North China Basalt 8 9Northeast Japan 11 45Northeast Japan 14 46Northeast Japan the 15 35Northeast Japan to the 15 47Northeast Japan Yanagawa 16 51Northeast Japan Group 9 56Northeast Japan - An of 8 17Northeast Japan Block and 15 56Northeast Japan and Its 15 47Northeast and Southwest 1 92Northeastern Japan 12 66Northeastern Part of the 8 1Northeastern Yamaguchi 9 33Northeastern Yamaguchi 12 77Northern Chile 10 112Northern Chile 10 120Northern Kenya in the 12 59Northern Kenya of the 8 34Northern Kyushu Island, 4 116Northern Kyushu Island, 2 38Northern Part of Mie 5 69Northern Peru Pre-Inca 12 18

from the Western andConstraint on the

Evidence forEvidence of the

Y. Otofuji, Largeand Adjacent Areas,and Ida Volcanoes in

from the Izumi Group inKatsura, and S. Sasajima,

H. Domen, ProgressH. Domen, A ShortH. Domen, Progress

of H. Domen, A ShortKatsura and S. Sasajima,

Measurement H. Domen, Aand H. Muneoka, A Brief

Effect of T. Nagata,Ito, K. Tokieda, and Y.Ito, K. Tokieda, and Y.Ito, K. Tokieda, and Y.

H. Ito, K.Tokieda, and Y.K. J. Matsuda, K.Fujioka, I. Kaneoka, K.Paleomagnetism of Y.and Paleomagnetism in the

Professor Naoto Kawai:from Archeologicalfrom Archeological

Secondary Magnetizationsto East Asian ResultsBasin and Daito Area

of the Geomagnetic FieldFlows in in the Holocene

The Polarity Changeand Fission Track Ages

and M. Ozima, Rare Gasand K. Aoki, Possible

M.Y. An Evidence for thein a Pyroclastic Flow

Comore Islands, Indianfrom the South PacificPaleomagnetism of the

Joshima, Magnetization ofMagnetic Structures ofA. Taira, T. Ui, and L.

Paleomagnetism of NeogeneHayashida, H.Doi, Abrupt S. Sakai, H.Thermal M. Torii, H.Peninsula Results of theR. T. Fujiwara, S.Min, Y. Otofuji, J.Y.

Investigation ofClockwise Rotation in theby Thunderbolts Found in

Y. Fujiwara, S.Ultramafic Rocks from the

and Triassic Rocks fromGranitic Rocks fromVolcanic Rocks from

Paleomagnetic Study ofLow 40Ar/36Ar Ratios in

High 3He/4He Ratios inOzima, Growth of Nickel

Furuta,and T. Y.Intensity Variation of

Internal M. Hyodo, S.Joshima, K. Shibata, K.Pleistocene Recorded in

K. Heki, H. Kinoshita, Y.M. Kono, N. Ueno, and Y.H. Ueno and M. Nedachi,

Hydrothermal H. Ueno,When Was the Japan Sea

Japan - Fan Shapeof the Hayama-Mineoka

for AF M. Kono,Biwa and the N. Kawai,

Northern Sulawesi, East 5 7;\Northern and Southern 15 ,,(iNorthward Drift and Local 10 (\1Northward Drift of the 10,,~

Northward Translation of 14 RONorthwest Izu Peninsula, 9 17Northwestern Izu Daruma 10 ,,0Northwestern Shikoku, 12~"

Note on Effects of Drying 6 40Note on Paleo/Rock 14 :lGNote on Thermo-Magnetic 4Note on Thermomagnetic l1!lnNote on an NRM Direction 10 J~R

Note on the Experimental 8 67Note on the NRM 5 ·10Note on the Remanent 2 ~2

Notes on Integrated 1 J~Notsu, A Paleomagnetic 6 11 ~

Notsu, Paleomagnetic H. 8 40Notsu, Paleomagnetism of 6 5RNotsu, Remanent 9 24Notsu,T. Kikukawa, and 8 100Notsu, Y. Takigami, K. 13 48Notsu and H. Ito, 9 5~

Numajiri Hydrothermal 12 GGObituary H. Domen, 6 IObjects Deduced 6 GJObjects in Japan Deduced 12 12Observed in Nawakot the 14 G8Obtained Emphasis 6 noObtained by the Deep Sea 5 J J IObtained from Pre-Inca 12 J8Obtained from the Lava 6 2"Obtained from the 3 41Obtained from the Western 5 73Occlusion into Grains 4 J4 7Occurrence of Excess 12 8nOccurrence of about 80 5 8JOccurring in Southern 1 47Ocean Reunion and Grande 11 107Ocean: Samoa, Rarotonga, 8 100Ocean Sediments of 5 IIIOceanic Basalts M. 1 9Oceanic Crust Rock I IOcola, Geophysical 9 GGOcros Dike Swarm near 10 10"Oda, M. Torii, and A. 16 "IOda, T. Nakayama, and H. 16 IOda, and H. Shibuya, 16 20Ofuna Formation, Miura 9 4Ogura, H. Kinoshita, and 16 4Oh, T. Hirasawa, lCD. 8 4GOhdateno Remain in Akita 16 30Oiso Hills: A Possible 15 35Ojima Andesite, Fukui 6 52Okada, and N. Aida, 4 14Oki-Dogo Island, Japan 3 8"Okinawa-Jima, Ryukyu, 6 12GOkushiri Island, West 9 5~

Okutango Peninsula, Japan 8 22Oligocene to Miocene 12 4-1Olivine Megacryst Nodules 12 89Olivine Phenocrysts of 4 13nOlivine Single Crystals 3 18Onda, S. Sugihara, T. 9 4One-Axis ARM with Angle 5 IOnishi, and K. Yaskawa, 10 29Ono, and Ujike, M. 5 GSOntake Tephra, Ina, 4 81Onuki, A. Taira, T. Ui, 9 6GOnuki, Paleointensities 12 18Opaque Mineralogy and 12 GGOpaque Minerals in 16 16Opened?: Paleomagnetic 11 r,9Opening of the Southwest 13 6Ophiolite, 6 107Optimum Design of Coils 6 J.1GOrganic Elements in Lake 3 ]0(\

81

Evidence of Major AeolianKatsura, and S. Sasajima,H. Tanaka and M. Kono,

the and K. Nakazawa, TheApproach to the

Sediments Collected fromPaleomagnetism of

Volcanic Ash Layer in theAsh Horizon Sediments in

Ash Layers in theEpoch Boundary in the

Azuki Tuff in PleistocenePaleomagnetic Study of

Clays near Komyoike,Measured and Compiled in

and K. Kobayashi, Thefrom the Lava Flows in

the Fudeshima Dike Swarm,Magnetization of Izu

of Kitakami Mountains andDecomposition of O.Magnetic Surveying of N.

Miocene Granite from theand M. Torii, When Y.Mild, T. Matsuda, and Y.,

S. Sasajima, Note on Y.S. Sasajima, Origin Y.Hirasawa, KD. Min, Y.Suparka, S. Sasajima, Y.Inokuchi, H. Y.Translation of East Y.

Adachi, H. Inokuchi, Y.Study on M. Miki and Y.M. Miki, S. Kondo, and Y.Matsuo, F. Murata, T. Y.Nishimura, and F. Y.Matsuda, Fast Y.and J. Nishida, Y.S. Nohda, Y.Nishimura, K. Hirooka,.Y.

Funahara, F. Murata, Y.Yoshida, T. Tagami, Y.

A. Hayashida, Y.Experimental Study on Y.On the T. Hirajima, Y.Amount of Clockwise Y.Paleomagnetism of Y.Paleomagnetism of Y.

Cretaceous Series in theon the Low-Temperature

of TRM in a HighlyDemagnetization Using

of Partial Pressure ofBasalts K Saito and M.Age of a K. Saito and M.Matsuda, S. Zashu, and M.Plastic Deformation M.Atmosphere: M.Olivine Single M.DSDP Leg K. Saito and M.Material Interaction M.

N. Takaoka and M.into M. Honda and M.Matsuda, S. Zashu, and M.Mechanism of Trace M.Jr., Rare Gas M.Jr., Some Comments on M.

O. Matsubayashi, M.The Origin of Rate M.

M. Kono,M.Rock Magnetic M.40Ar-39Ar I. Kaneoka, M.Implication of M.

in the Central EquatorialIsland, the Southeast

Island Arc in the WesternEquator from the Central

in Penrhyn Basin, South

Origin South Pacific: 12 53Origin of Decay of 1. 8 61Origin of NRM of San Juan 2 20Origin of Rate Gases in 6 86Origin of the Japan Sea 1 77Osaka Bay of the Young 6 14Osaka Bay Sediments 4 76Osaka Group a Water-Laid 1 65Osaka Group Volcanic 5 49Osaka Group, Sennan and 2 34Osaka Group, Southwest 14 27Osaka Group, Southwest 15 4Osaka Group Using Marine 3 32Osaka Prefecture 3 32Osaka University Japan 6 10Oscillation of Field in 1 53Oshima Island Obtained 6 25Oshima Island, Central 11 26Oshima Lava Flow in 1986 15 1Oshima Peninsula of 6 113Oshima, Reduction 9 102Oshiman and H. Tanaka, 6 7Osumi Peninsula Middle 13 8Otofuji, A. Hayashida, 11 59Otofuji, Clockwise M. 14 38Otofuji, 1. Katsura, and 6 40Otofuji, 1. Katsura, and 8 61Otofuji, J.Y. Oh, T. 8 46Otofuji, K. Hirooka, 5 104Otofuji, K.H. Kiln, H. 12 51Otofuji, Large Northward 14 80Otofuji, N. Isezaki, and 14 72Otofuji, Paleomagnetic 16 44Otofuji, Paleomagnetic 16 47Otofuji, S. Funahara, J. 14 78Otofuji, S. Sasajima, S. 6 69Otofuji, T. Itaya, and T. 16 49Otofuji, T. Makinouchi, 3 36Otofuji, T. Matsuda, and 11 45Otofuji, T.V. Leeuwen, 5 73Otofuji, Y. Inoue, S. 15 59Otofuji, Y. Maeda, and S. 10 33Otofuji, and M. Torii, 11 61Otofuji and S. Sasajima, 4 53Otofuji, and S. Sasajima, 5 27Otofuji and T. Matsuda, 13 6Otofuji and T. Matsuda, 9 41Otofuji and T. Matsuda, 10 69Outer Zone of Southwest 12 38Oxidation of Size Effect 6 128Oxidized Submarine Basalt 2 5Oxygen Partial Pressure 2 24Oxygen on Thermoremanent 3 10Ozima, 40Ar-39Ar Ages of 2 71Ozima, 40Ar-39ArIsochron 3 81Ozima, Anomalously High 1 102Ozima, Effects of a 6 123Ozima, Evolution of the 1 111Ozima, Growth of Nickel 3 18Ozima, K-Ar Ages of Six 1 98Ozima, On Mantle-Crust 2 76Ozima, Rare Gas Isotopic 4 144Ozima, Rare Gas Ocdusion 4 147Ozima, Sr Isotopic J. 2 66Ozima, Transport 4 155Ozima and E.C. Alexander, 3 91Ozima and E.C. Alexander, 3 100Ozima, and I. Kaneoka, A 2 62Ozima and K. Nakazawa, 6 86Ozima, and K.Wadatsumi, 2 45Ozima and M. Joshima, 1 1Ozima, and M. Yanagisawa, 5 84Ozima and S. Matsuo, 4 151Pacific Sediments 13 19Pacific Ages in Easter 15 25Pacific Rocks from the 2 66Pacific Basin near the 10 38Pacific: Evidence of 12 53

Rocks from the Southbetween Eurasia and

Paleomagnetism of theDomen, Progress Note on

A Preliminary Report on aDomen, Progress Report onof the H. Domen, On a

Paleomagnetism anda Paleomagnetic andH. Goto, and K Yaskawa,

Study of Cretaceous­Muneoka, Examples of the

H. Tanaka, Geomagneticof Geomagnetic

Two Dated H. Tanaka,M. Kono, Geomagnetic

H. Tanaka, ThreeHolocene H. Tanaka, FourGeomagnetic H. Tanaka,

N. Ueno, and Y. Onuki,the Thelliers' Method ofthe Thelliers' Method of

M. Kono and N. Ueno,M. Kono, An Attempt of

by Field Dependence ofT. Tosha and M. Kono,M. Kono, Reliability of

Kono, Paleomagnetism and75,000 Years H. Sakai,Japan - An Estimation of

On the Determination ofand S. Ishida, The

Tokieda, and Y. Notsu, Asince Late Mesozoic, - A

of the and T. Yokoyama,Tanaka and H. Tsunakawa,of the Late K. Hirooka,

H. Suzuki, PreliminaryH. Domen, A Couple of

M. Torii and N. Ishikawa,Hokkaido - From

for NorthwardM. Koyama,Koyama and H. Kitazato,

for Rapid M. Torii,X. Zheng, and K. Yaskawa,T. Matsuda, and S. Nohda,for the and F. Hehuwat,

the Japan Sea Opened?:the Duration of H. Ueno,H. Sakai, and T. Nakajima

M. Kono, Statistics ofNishitani and S. Tanoue,

Investigation M. Torii,Hirooka, and A. Takeuchi,of the Miyako T. Tosha,Y. Maeda, and S. SasajimaM. Torii, Late Cretaceous

Katao, and K. Yaskawa, AP. Gautam, A

H. Ito and K. Tokieda, AInternal Consistency of

Leeuwen, and Hehuwat,Fujiwara, A PreliminaryTorii and H. Tsurudome,

K Tokieda, and Y. Notsu,Kinoshita and T. Akimoto,

Furuta, and T. Akimoto,T. Yamazaki,

Islands Inferred fromthe South M. Koyama,

M. Funaki and M. Yoshida,Suwijanto, and F. Hehuwa

Torii, and A. Hayashida,Y. Hamano, and M. Kono,A. Tokuyama, and H. Ito,Y. Hamano, and M. Kono,Part of Southwest Japan:F. Murata, and X. Zheng,

Pacific Ocean: Samoa, 8 100Pacific Plates in 11 61Palau and the Yap Island 14 72Paleo/Rock Magnetic Study 14 36Paleo/Rock Magnetic Study 5.J7Paleo/Rock Magnetic Study 10 134Paleo/Rock Magnetic Study 9 33Paleodimate K. Hirooka, 3 110Paleodimatic Study with 11 HjPaleoenvironmental 16 :IXPaleogene Deposits 14 !;2Paleogeomagnetic Field 4 lO4Paleointensities During 5 Dr;

Paleointensities from the 4 7:1Paleointensities from the 6 27Paleointensities in the 1 R3Paleointensities in the 6 2!;Paleointensities in the 6 30Paleointensities of the 5 R7Paleointensities of the 12 JRPaleointensity of 10 DPaleointensity of 10 HiPaleointensity 3 61Paleointensity 1 RRPaleointensity Determined 5 IRPaleointensity 6 61Paleointensity Methods 4 22Paleointensity Studies of 5 ORPaleointensity at the 16 42Paleointensity in Miocene 8 2R"Paleolongitude" in 6 1Paleomagnetic Yaskawa, 14 40Paleomagnetic Approach to 6 11:1Paleomagnetic Approach to 1 77Paleomagnetic Chronology 6 4R

.Paleomagnetic Constraint 15 56Paleomagnetic Correlation 6 7RPaleomagnetic Data from 15 6·1Paleomagnetic Data of the 9 61Paleomagnetic Directions 13 1Paleomagnetic Evidence - 13 1',Paleomagnetic Evidence 10 61Paleomagnetic Evidence 15 3"Paleomagnetic Evidence 10 77Paleomagnetic Evidence 14 7RPaleomagnetic Evidence 11 4!;Paleomagnetic Evidence 6 (iB

Paleomagnetic Evidence 11 50Paleomagnetic Evidence of 2 ·10Paleomagnetic Evidence of 10 ,,3Paleomagnetic Inclination 6 151Paleomagnetic T. 14 46Paleomagnetic I 6"Paleomagnetic Measurement 11 :IRPaleomagnetic Measurement 9!;6Paleomagnetic Otofuji, 10 3:1Paleomagnetic Pole from 13 16Paleomagnetic Murata, H. 12 !; 1Paleomagnetic 13 30Paleomagnetic Record of 3 5(1Paleomagnetic Records in 10 20Paleomagnetic Results and 5 7:1Paleomagnetic Results Y. 12 2"Paleomagnetic Results M. 14 ,,0Paleomagnetic Results of 8 ·10Paleomagnetic Results of 14 23Paleomagnetic Results of 9·1Paleomagnetic 13 10Paleomagnetic Studies 10 0:\Paleomagnetic Studies in 15 30Paleomagnetic Studies of 13 3!;Paleomagnetic Studies on 5 1(J·1Paleomagnetic Study and 16!; IPaleomagnetic Study in 9 72Paleomagnetic Study of 11 n:1Paleomagnetic Study of 10 1J2Paleomagnetic Study of 13 12Paleomagnetic Study of 15 50

82

and H. Kinoshita, Paleomagnetic Study of 10 120 Preliminary Results from Paleomagnetism on 16 :,/Sakai, and T. Yokoyama, Paleomagnetic Study of 4 88 and M. Itihara, Paleomagnetism on the 2 :H

Japan, Inferred from Paleomagnetic Study of 12 44 and M. Torii, Preliminary Paleomangetic Studies on 6 I:WJ. Nishida and S. Ishida, Paleomagnetic Study of 3 32 Y. Otofuji, and M. Torii, Paleoposition of 11 01

and P.W. Vitanage, Paleomagnetic Study of 14 86 Island, Evidence for the Paleoposition of Sumba 6 (j!1

H. Sakai and S. Maruyama, Paleomagnetic Study of 11 68 and Study of Geomagnetic Paleosecular Variation 15 'j'_.,Secular K. Heki, Paleomagnetic Study of 6 72 Site, and the Holocene Paleosecular Variation in 6 IRDomen and H. Muneoka, A Paleomagnetic Study of 9 36 Remanent Magnetization of Paleozoic Greenstoness in 3 jli

H. Ito and K. Tokieda, A Paleomagnetic Study of 3 67 Paleomagnetic Studies of Paleozoic Rocks from the 13 :~rl

M. Torii and Y. Tatsurni, Paleomagnetic Study of 6 105 Remagnetization of the Paleozoic Rocks in the 10 Ii'.,A Progress Report on Paleomagnetic Study on 2 38 Late Precambrian to Early Paleozoic Rocks of Tansen 13 :~!l

A Progress Report on Paleomagnetic Study on 8 38 Rocks of Data from the Paleozoic and Mesozoic 15 n'lM. Miki and Y. Otofuji, Paleomagnetic Study on 16 44 Data in Parallel Sections 3 17

and S. Sasajima, A Paleomagnetic Study on 8 53 Motion On Estimation of Parameters of Turbulent 2 1\·1Y. Itoh and M. Torii, Paleomagnetic Study on 11 51 Setouchi Volcanic Belt. Part 1. Shodo-Shima the 6 lor)

and S. Sasajima, A Paleomagnetic Study on 6 121 Area, Central Japan (Part I) in Inuyama 6 121of the Chubu District: Paleomagnetic Study on Y. 12 29 Anomaly in Southern Part of Boso Peninsula, 14 nn

S. Kondo, and Y. Otofuji, Paleomagnetic Study on 16 47 of Sumatra Being Part of Gondwanaland 5 10·1S. Sasajima, Preliminary Paleomagnetic Study on 12 38 Rocks in Southern Part of Korean Peninsul 12 rli

Inokuchi, and K. Yaskawa, Paleomagnetic and H. 11 16 Age Group in the Northern Part of Mie Prefecture, 5 (in

T. Ishii, Reconnaissance Paleomagnetic and Rock 9 106 Rotation of the Eastern Part of Southwest Japan: 13 12Two-Disk Dynamo and Paleomagnetism Rikitake 13 71 in the Northeastern Part of the Izu Deposit.s 8 I

Ryukyu Arc Inferred from Paleomagnetism the South 14 38 in the Eastern Part of the Japan Basin 15 !iOof "Paleolongitude" in Paleomagnetism 6 1 of the Southwestern Part of the Japan Sea - 13 ()

H. Ito and K. Tokieda, Paleomagnetism and 4 118 Dredged from the Central Part of the Japan Sea 15 r):~

Nakajima and Y. Morimoto, Paleomagnetism and T. 8 22 Techniques Using Oxygen Partial Pressure Control 2 2'1Miyachi, and I. Hirano, Paleomagnetism and M. 11 21 H. Tanaka, Influence of Partial Pressure of and 3 10

Min, and S. Sasajima, Paleomagnetism and K-Ar 8 46 Concentration in Metal Particles of Lunar and 1 21Age K. Ono, and Ujike, Paleomagnetism and K-Ar 5 65 Japan During the Past 30,000 Years in 5 0:1

J. Matsuda and K. Yaskawa Paleomagnetism and K-Ar 14 75 of Reconstruction of the Past Geomagnetic Field 10 12Ozima, and K. Wadatsumi, Paleomagnetism and K-Ar 2 45 from Polar Wandering Path for East Asia 14 RO

Japan Inferred from Paleomagnetism and K-Ar 16 49 on Apparent Polar Wander Path for the South China 16 !iTTokieda, and K. Hirooka, Paleomagnetism and K. 3 110 Rare Gas Fractionation Patterns in Terrestrial 3 nl

Paleointensity M. Kono, Paleomagnetism and 5 98 Remanent Magnetization of Pelagic Clay and Viscous 15 7Tibet as Inferred from Paleomagnetism and St 16 38 Basin, Magnetization of Pelagic Clay in Penrhyn 12 5:l

Progress Report on Paleomagnetism in the 4 95 Southern Part of Korean Peninsul Rocks in 12 51Opaque Mineralogy and Paleomagnetism in the 12 66 Coastal Area of the Kii Peninsula the Western 11 5:)

Progress Report on Paleomagnetism of 3 51 Granite from the Osumi Peninsula Middle Miocene 13 RH. Ito and K. Tokieda, Paleomagnetism of 2 59 Tokoname Group in Chita Peninsula of 3 3H

Y. Notsu and H. Ito, Paleomagnetism of 9 53 Ofuna Formation, Miura Peninsula Results of the 9 1Kinoshita, and T. Furuta, Paleomagnetism of Daruma 9 17 Rocks from Korean Peninsula - Gyeongsang 8 1()

Morinaga, and K. Yaskawa, Paleomagnetism of H. 6 68 in Northwestern Izu Peninsula, Central Japan 10 50Kinoshita and T. Furuta, Paleomagnetism of Hole 14 66 Drift of -the Izu Peninsula, Central Japan 10 53Otofuji and T. Matsuda, Paleomagnetism of Igneous 9 41 Part of the Izu Peninsula, Central Japan 8 1

Komyoike K. Maenaka, Paleomagnetism of 5 49 in Southern Part of Boso Peninsula, Chiba, Japan 14 nnTorii, and N. Natsuhara, Paleomagnetism of Lake 3 24 in the South Boso Peninsula Inferred from 16 1

Miocene Muro M. Torii, Paleomagnetism of Middle 6 52 the Matsuzaki Area, Izu Peninsula, Japan of 10 HIK. Tokieda, and Y. Notsu, Paleomagnetism of Miocene 6 58 Rocks from Okutango Peninsula, Japan 8 :12T. Nakajima and M. Torii, Paleomagnetism of Miocene 12 59 Areas, Northwest Izu Peninsula, Japan 9 17Sedimentary T. Yamazaki, Paleomagnetism of Miocene 15 47 Volcanics In the Izu Peninsula and Adjacent 14 21

M. Kono, and T. Ui, Paleomagnetism of Neogene 10 105 Investigation for the Peninsula in Northeast 14 16S. Muroi and K. Yaskawa, Paleomagnetism of Osaka 4 76 Mountains and Oshima Peninsula of Hokkaido, 6 ll3Nishida, and S. Sasajima, Paleomagnetism of Permian 6 130 of Pelagic Clay in Penrhyn Basin, South 12 53

Susanto, and H. Wahyono, Paleomagnetism of E.E. 15 31 and Phlogopite-Bearing Peridotites in South 4 130Koyama, and H. Kinoshita, Paleomagnetism of M. 14 24 of Sumatra in Quaternary Period Rotation 10 100

Shibuya and S. Sasajima, Paleomagnetism of Red H. 10 87 Determination on Permian Porphyllites and 1 lI8Preliminary Study of Paleomagnetism of Some 8 9 Tamba Paleomagnetism of Permian Red Chert in the 6 1:10

in Limestone Cave by Paleomagnetism of 15 15 Rocks Studies on the Permian and Triassic 6 12nField Deduced from Paleomagnetism of 14 18 Reconnaissance of Permian to Cretaceous 12 ;,1

Otofuji and T. Matsuda, Paleomagnet.ism of Y. 10 69 near Cajamarca, Northern Peru Pre· Inca Potsherds 12 IIIM. Hyodo and K. Yaskawa, Paleomagnetism of a Core 11 10 Volcanic Rocks, Southern Peru Quaternary Andean 9 IIIM. Hyodo and K. Yaskawa, Paleomagnetism of a 11 4 Study in Andean Peru: Cretaceous 9 72

T. Miki, and M. !keya, Paleomagnetism of a 13 51 Dike Swarm near Ayacucho, Peruvian Andes Geros 10 10:)Morinaga, and K. Yaskawa, Paleomagnetism of a K.S. 12 6 Anomaly across the Peruvian Andes Gravity 15 6r,

Preliminary Report on Paleomagnetism of a 15 21 a Slightly Less Magnetic Phase in the Change to 11 nnTsunakawa, and Y. Hamano, Paleomagnetism of the H. 9 9 3He/4He Ratios in Olivine Phenocrysts of Kapuho 4 1:10

Cenozoic M. Koyama, Paleomagnetism of the 8 1 or Deformational Phenomena? 15 28Fudeshima E. Kikawa, Paleomagnetism of the 11 26 on Seismo-Magnetic Phenomena - to Studies 1 :!6

Magnetic Anomaly and Paleomagnetism of the 6 107 to the Development of the Philippine Basin 4 lORIbaragi, and R. Suzuki, Paleomagnetism of the K. 14 31 Core Collected from the Philippine Sea Sediment 4 n

Kikawa and H. Kinoshita, Paleomagnetism of the Izu 11 31 Anomaly Lineations in the Philippine Sea Magnet.ic 5 1111Ocean H. Kinoshit Paleomagnetism of the 5 111 Yaskawa, Rotation of the Philippine Sea Plate K. 14 i:l

Sea Plate Inferred from Paleomagnetism of the 14 72 Interaction between the Philippine Sea Plate and 15 :H;S. Sasajima, Tertiary Paleomagnetism of the 4 108 40Ar/39Ar Analyses of Phlogopite Nodules and 4 1:10

H. Tanaka and M. Kono, Paleomagnetism of the San 1 71 of Phlogopite Nodules and Phlogopite-Bearing 4 130Japan Inferred from Paleomagnetism of the 12 33 Kenya of the Miocene Phonolite from Northern 8 :).1

Tosha and H. Tsunakawa, Paleomagnetism of the T. 8 28 Paleomagnetism of a Phosphorite Module 13 !)]

K. Heki and H. Tsunakawa, Paleomagnetism of the 8 17 of a Stalagmite, in Ping Le, South China 15 21

83

An Approach to Study theof ESR Signals from

M. Ozima, Effects of aof Southwest Japan and

of the Philippine SeaProblem of Instantaneous

the Philippine Seafrom West Akiyoshi

Time Eurasia and PacificRotation in Evidence for

of the Azuki Tuff inFall Properties of the

Excursion of the LatestRecorded in the Late

Correlation of the LateS. Zashu, and S. Kawachi,

"Kanto Loam" the LateHolocene and the Latest

Magnetosratigraphy of theRemanent Magnetization ofGroup Chronology of the

Volcanic Ash Layers inPaleomagnetism of

Earth's Magnetic Field inof Meteorites F.A.South China on Apparent

Last 20 My Inferred fromfrom the K. Maenaka, The

T. Nakajima, BlakeBrunhes of a Magnetic

in Brunhes Normalin The Brunhes/Matuyamain the Brunhes/Maruyamaand M. Nedachi, Magnetic

A Paleomagnetic Record ofCretaceous PaleomagneticIsland, Marquesas, French

of Basaltic Rocks fromDetermination on PermianReconstruction M. Hyodo,on Sumatra Island: On theRevealed in S. Sasajima,

N. Takaoka, and K. Aoki,in the Oiso Hills: A

Paleomagnetic Approach toon Effects of Drying onExperimental Study onof the Lock-In Zone of

Origin of Decay ofFujiwara and R. Sugiyama,

Obtained from Pre-IncaForce at the Blast by Gun

Surface Soils Found in aField Obtained fromOn the Existence of

and Pacific Plates inMagnetization of Late

Paleomagnetic Study ofPaleozoic of Some Lateon Baked Earths in Kyoto

Ohdateno Remain in Akitanear Komyoike, Osaka

at Kasa-Yama, YamaguchiIsland, Kagoshima

in Ojima Andesite, Fukuithe Yatsuo Area in ToyamaKuroko Mining Area, AkitaShiga Welded Tuff, Nagano

the Northern Part of MieNortheastern Yamaguchi

Cenozoic Basalt, Sagathe Inner Zone of Ehime

JapanComplex, YamaguchiSouthcentral YamaguchiNortheastern Yamaguchi

End of Yamaguchithe Central YamaguchiDeposits in Yamaguchi

Planet Formation 4Planktonic Foraminifera 10Plastic Deformation on a 6Plate Convergence between 11Plate Inferred from 14Plate Kinematics by Using 11Plate and Northeast Japan 15Plateau, Japan Collected 16Plates in Pre-Neogene 11Pleistocene Clockwise 15Pleistocene Osaka Group, 15Pleistocene Pyroclastic 6Pleistocene Recorded in 4Pleistocene Sediments 1Pleistocene Tephra 6Pleistocene Volcanic 6Pleistocene Volcanic of 4Pleistocene from the the 6Plio-Pleistocene Age 5Plio-Pleistocene Natural 3Plio-Pleistocene Kobiwako 6Plio-Pleistocene 3Plio-Pleistocene 15Pliocene of the 3Podosek, Radiometric Ages 6Polar Wander Path for the 16Polar Wandering Path for 14Polarity Change Obtained 3Polarity Episode in a 9Polarity Episode in the 6Polarity Epoch Reversals 1Polarity Epoch Boundary 5Polarity Epoch Boundary 14Polarity Sequence of the 15Polarity Transitions of 3Pole from the Koto Late 13Polynesia in Hiba-oa 14Ponape Island, East 9Porphyllites and Tertiary 1Possibility of 10Possibility of Sumatra 5Possible Blake Event as 1Possible Occurrence of 12Possible Record of 15Possible Tilting A 6Post Depositional Note 6Post-Depositional 4Post-Depositional 11Post-Depositional 8Post-Oligocene Tectonic 13Potsherds near Cajamarca, 12Powder - Interpretation 16Pre-Ceramic Site of 15Pre-Inca Potsherds near 12Pre-Jaramillo Event in 6Pre-Neogene Time Eurasia 11Precambrian Rocks in 6Precambrian Rocks of Sri 14Precambrian to Early 13Prefecture Measurements 11Prefecture of 16Prefecture Clays 3Prefecture Basalt 5Prefecture Kuro-Shima 5Prefecture Found 6Prefecture, Japan around 14Prefecture, Japan 15Prefecture, Japan Age of 3Prefecture, Japan in 5Prefecture, Japan 9Prefecture, Northern 4Prefecture, Shikoku from 11Prefecture, Southwest 9Prefecture, West Japan 10Prefecture, West Japan 12Prefecture, West Japan 13Prefecture, West Japan 14Prefecture, West Japan 2

147 South-Central Yamaguchi7 the Southeast Yamaguchi

123 West End of Yamaguchi61 Ash of Central Yamaguchi72 Tokuyama City, Yamaguchi

120 Yamaguchi and Shimane35 Ozima, and 1. Kaneoka, A33 of Basement M. Funaki, A61 Hayashida and H. Suzuki,35 Results Y. Fujiwara, A

4 Maenaka and S. Sasajima,46 S. Sasajima and M. Torli,81 Hishikari Gold Deposits;51 1. Shodo-Shima Island78 Belt, Southwest Japan

100 Brunhes Normal Epoch: A88 M. Hyodo and K. Yaskawa,30 and J. Nishida,69 Maruyama, and Y. Yaskawa,52 ThermomagnetidI. Domen,48 Paleo/Rock H. Domen, A41 Isezaki, and K. Yaskawa,31 H. Domen and H. Muneoka,56 Fang, and K. Yaskawa,94 Isezaki, and K. Yaskawa,57 Maenaka, and S. Sasajima,80 Stability of H. Domen,41 Re-Magnetization in the13 Adjacent Areas, Japan -85 Using Oxygen Partial44 Influence of Partial55 of Pure Iron at High27 of Solid under High41 S. Matsuo, Implication of56 New Spinner Magnetometer:16 M. Kono, Uniqueness75 K. Heki, The Inverse

106 Sea and Its Relevant88 Solving Kinematic Dynamo42 Y. Hamano, Consolidation

104 Obituary H. Domen,47 Paleo/Rock H. Domen,89 ThermomagnetidI. Domen,35 H. Muneoka and H. Domen,

113 Domon and H. Muneoka, A40 Domen and H. Muneoka, A53 Kawai, and K. Kobayashi,85 Muneoka, and T. Yokoyama,61 by the Deep Sea Drilling15 from Deep Sea Drilling18 System: Statistical

1 and S. Akimoto, Magnetic11 and T. Nagata, Magnetic18 and T. Katsura Magnetic94 Kono, Changes in Magnetic61 and T. Danhara, Magnetic75 and T. Furuta, Magnetic86 Yoshida, Thermomagnetic39 Magnetic Hysteresis1 Domen, On Thermomagnetic

30 Domen, On Thermomagnetic32 Basalt Group in Datong47 Remanence in the Andesite65 Y. Hamano, The Melting of52 Ferromagnetic Minerals in42 in of the Pleistocene41 Event as Revealed in a79 Indentification of69 Myokofrom the Two Dated33 of Noble Gases with a

116 Preliminary Experiment on63 Alteration Zone of24 of the Late Tertiary and

138 Rotation of Sumatra in77 the Paleomagnetism of66 of the Late Neogene to36 Meteorites F.A. Podosek,32 of Evidence for

84

Prefecture, \Vest Japan 3Prefecture, \Vest Japan 3Prefecture, West Japan 4Prefecture, West Japan. 4Prefecture, West Japan 9Prefectures, \Vest Japan 9Preliminary Experiment on 2Preliminary Investigation 9Preliminary Paleomagnetic 15Preliminary Paleomagnetic 12Preliminary Paleomagnetic 12Preliminary Paleomangetic 6Preliminary Report the 14(Preliminary Report) 6(Preliminary Report) 6Preliminary Report the 6Preliminary Report of 12Preliminary Report of 3Preliminary Report on H. 15Preliminary Report on 8Preliminary Report on a 5Preliminary Report on the 6Preliminary Report on the 10Preliminary Results from 16Preliminary Study of N. 15Preliminary Study of K. 8Preriminary Report on the 4Present Geomagnetic Field 3Present Stat.us and a Data 15Pressure Control 2Pressure of Oxygen on 3Pressures The Melting 2Pressures and High IPrimordial 3He Degassing 4Principles and Techniques 6Problem in the Spherical 3Problem of Instantaneous 11Problems of the Japan 10Problems Automatically 16Process in the 4Professor Naoto Kawai: 6Progress Note on 14Progress Note on 11Progress Report on 10Progress Report on H. 2Progress Report on H. 8Progress Report on N. 4Progress Report on H. 3Project, Cruise Leg 58, 5Project Holes 597B and 10Properties and Growth of 14Properties of J(jmberlite 2Properties of Lamellar 12Properties of H. Tanaka, 4Properties of a Basalt 4Properties of the Azuki 15Properties of the Old 6Properties of the M. 6Properties of x = 0.5 6Property of So-called H. 9Property of an Icelandic 8Province, North China 8Pumice with Self-Reversed 14Pure Iron at High 2Pyroclastic Deposits in 4Pyroclastic Fall Deposits 6Pyroclastic Flow Blake 1Pyroclastic Flow by 6Pyroclastic Flows of the 6Quadrupole Type Mass 2Quanitative Determination 2Quartz Diorite Bodies, 13Quaternary Andean 9Quaternary Period 10Quaternary Volcanics In 14Quternary Deposits in the 8Radiometric Ages of 6Rapid Clockwise Rotation 10

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Remanent l\1agnetizatiol1 ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent Magnetization ofRemanent MagnetizationsRemanent Magnetzation ofRemanent Magnetzation ofRemenent MagnetizationRepeated Shocks on NotesReport Hishikari GoldReport) 1. Shodo-ShimaReport) Belt, SouthwestReport Brunhes NormalReport of Construction ofReport of andReport on Paleo/RockReport on PaleomagneticReport on PaleomagneticReport on PaleomagnetismReport on PaleomagnetismReport on PaleomagnetismReport on ThermomagneticReport on a Paleo/RockReport on the MagneticReport on the NaturalReport on the StabilityResonance Dating ofRespective RemanentResults Obtained SpecialResults and Fission TrackResults from Fang, andResults from the CentralResults from the Late H.Results of CretaceousResults of Izu and HakoneResults of Sempukuji K.Results of the Ofuna andReunion and Grande ComoreRevealed in a PyroclasticReversal of Remanence inReversal Recorded in theReversal in the LatestReversals GalacticReversals during LateReversals in BrunhesReverse MagnetizationsReversed Rock PropertyRhyolite: New EvidenceRhyolite, Southwest JapanRhyolite of Late Torii,Rhyolites, SouthwestRica Ridge Rock MagnetismRidge Basalt (87Sr/86Sr)Ridge Rock Magnetism andRidges in the Line ChainRikitake Two-Disk DynamoRikitake Two-Disk DynamoRing-Core Fluxgate forRiver Area - ClockwiseRiver Tertiary Basalt inRivers Region -Rock of an IcelandicRock Dusts MechanismsRock MagneticRock Magnetic StructuresRock Magnetism ZonesRock Magnetism and HoleRock from TaikazanRock in the Goto IslandsRocks Shocks on Remanent.Rocks StudyRocks from the NRM

Grain Size and ViscousM. Kimura, The Natural

H. Sakai and T. Nakajima,on Post Depositional

Slumped N. Niitsuma,P.W. Vitanage, Natural

Anomalous NaturalInokuchi, and K. Yaskawa,

K.Tokieda, and Y. Notsu,and S. Ishida, Natural

of M. Funaki, NaturalMuneoka, On the NaturalMuneoka, On the Natural

and K. Hirooka, Anomalouson Integrated Effect of

Deposits; PreliminaryIsland (PreliminaryJapan (Preliminary

Epoch: A PreliminaryK. Yaskawa, Preliminary

J. Nishida, Preliminaryand H. Domen, ProgressH. Muneoka, A ProgressH. Muneoka, A Progress

K. Kobayashi, Progressand T. Yokoyama, Progress

Y. Yaskawa, PreliminaryH. Domen, Preliminary

H. Domen, A PreliminaryK. Yaskawa, PreliminaryH. Muneoka, Preliminary

of H. Domen, PreriminaryT. Sato, Electron Spin

On Discrimination ofEmphasis to East Asian

Hehuwat, PaleomagneticK. Yaskawa, Preliminary

Preliminary PaleomagneticTsurudome, Paleomagnetic

Y. Notsu, PaleomagneticT. Akimoto, Paleomagnetic

Tokieda, ArcheomagneticT. Akimoto, Paleomagnetic

and a Dunite Nodule fromPossible Blake Event asSediment during a Field

K. Manabe, GeomagneticTachibana, A GeomagneticRotation and Geomagnetic

with Geomagnetic FieldNormal K. Yaskawa,Found from K. Kodama,of an Icelandic Matuyamathe Late Cretaceous Koto

Pole from the Kotoand T. Matsuda, the Nohithe Late Cretaceous Koto

and of Hole 504B, CostaRatio from Mid-Atlantic

of Hole 504B, Costa Ricaof Basalts Dredged from

M. Kono and M. Hoshi, Theand M. Kono,

and S. Kokubun, AMiocene Age from the Go

Magnetzation of ColumbiaDeformation of the Three

Matuyama Reversedfor Snow InvolvingPaleomagnetic and

M. Ozima and M. Joshima,and Their Relevance to504B, Costa Rica Ridge

of the Cretaceousof Miocene Granitic

Magnetization of Igneousof Oligocene to Miocene

of Cretaceous Granitic

Rare Gas Fractionation 3 91Rare Gas Isotopes and 6 79Rare Gas Isotopes in 1. 6 88Rare Gas Isotopic 4 144Rare Gas Occlusion into 4 147Rare Gas Solubility in 3 100Rarotonga, Rurutu, and 8 100Rate Caused by Changes in 1 114Rate Gases in the Earth 6 86Rate of Sedimentation for 1 39Ratio from Mid-Atlantic 1 102Ratio in the Earth's 1 106Ratios in Olivine with 12 89Ratios in Olivine Excess 4 139Rb, Sr and 40Ar/39Ar S. 3 85Re-Magnetization in the 3 22Recent 60,000 Years Found 1 34Recent Four Lava Flows of 5 87Reconnaissance 9 106Reconnaissance of Permian 12 51Reconnaissance of Some 13 39Reconstructed Ancient 2 28Reconstruction of the 10 42Reconstruction with Sri 14 86Record of Interaction 15 35Record of Polarity K. 3 56Recorded by Sediments in 10 23Recorded in Ontake 4 81Recorded in Silty 11 10Recorded in a Stalagmite 16 33Recorded in the Brunhes 15 28Recorded in the Late 1 51Recorded in the Stable 6 14Records in Sediments 10 29Recovered from the 10 38Red Chert in the Tamba 6 130Red Cherts: A Case Study 10 87Redistribution of Cations 2 10Reduction Decomposition 9 102Region - - Deformation 15 59Region, Central Japan - 6 100Relation to the Changes 9 102Relationships Constraint 6 88Relative to South Korea 1 77Relatively Low 40Ar/36Ar 12 89Relevance to Rock 16 16Relevance to the of the 4 108Relevant Problems 10 80Reliability of 4 22Remagnetization of the 10 85Remain in Akita 16 30Remains, the Cave Site, 6 18Remanence 4 22Remanence in Sediment 8 67Remanence in the Andesite 14 12Remanence of the Young 6 14Remanent Direction of the 13 8Remanent Magnetic 2 32Remanent Magnetism in 5 11Remanent Magnetism of 3 75Remanent Magnetism of 5 25Remanent Magnetism of the 2 28Remanent Magnetisms of 1 7Remanent Magnetization 16 1Remanent Magnetization 4 53Remanent Magnetization in 11 85Remanent Magnetization in 8 61Remanent Magnetization of 4 106Remanent Magnetization of 10 137Remanent Magnetization of 6 123Remanent Magnetization of 4 36Remanent Magnetization of 11 75Remanent Magnetization of 4 72Remanent Magnetization of 2 50Remanent Magnetization of 1 13Remanent Magnetization of 15 1Remanent Magnetization of 6 75Remanent Magnetization of 3 76

and E.C. Alexander, Jr.,Mass I. Kaneoka,Kaneoka and N. Takaoka,

N. Takaoka and M. Ozima,M. Honda and M. Ozima,

Jr., Some Comments onPacific Ocean: Samoa,

the in the Earth's SpinNakazawa, The Origin of

Young Loose K. Yaskawa,Ridge High (87Sr/86Sr)

The Argon-40/ Argon-36Relatively Low 40Ar/36Ar129Xe and High 3He/4HeZashu, and E. Takahashi,by the Stepwise De- and

from Variation in theField Determined from

T. Furuta, and T. Ishii,Yaskawa, A PaleomagneticGautam, A Paleomagnetic

Remanent Magnetism of theM. Hyodo, Possibility of

Lanka in View of GondwanaOiso Hills: A Possible

Tokieda, A Paleomagnetic9,000 y.B.P. in Japan

of the Latest Pleistocenell: A Secular Variation

A Geomagnetic ExcursionM. Torii, Two UEvents ll

Geomagnetic ReversalSecular Variationof Paleomagnetic

Eevent in the Core Pl71Paleomagnetism of Permianin the Paleomagnetism of

Self-Reversal Caused byof O. Oshima,

of the Three RiversK-Ar in the Fossa Magna

a Cooling Magma and Itsof Their Genetic

Drift of Southwest Japan129Xe Associated with

Zones anI! TheirRyukyu !slanas and Its

of the Japan Sea and ItsPaleointensity M. Kono,

A. Morinaga, CretaceousInvestigation of Ohdateno

and Results of Sempukujiand Anhysteretic

during a Acquisition ofKatsui, On the Nature of

in the Stable MagneticTorii, Westerly Deflected

A Brief Note on theSecondary Component of

H. Ito, and S. Kume,K. Momose, Stability ofIkeguchi, and N. Kawai,

of Respective- Interpretation by

on Post-DepositionalZone of Post-Depositional

Wet of Post-DepositionalClassified Natural

Report on the NaturalPlastic Deformation on a

the Stability of NaturalDirt M. Funaki, Natural

H. Muneoka, On NaturalKanaya and K. Noritomi,

of Repeated Shocks onS. Sasaki, Measurement of

K. Suwa, and S. Kume,the Intensity of Natural

85

of Cretaceous Granitic Rocks Composition 4 118 Subduction Complex, SW Japan in Jurassic 11 HXMarine Sedimentary Rocks of Slumped 4 44 Karatsu Cenozoic Basalt, Saga Prefecture, Northern 4 Ilfl

and TRM in Some Andesitic Rocks Directions of CRM 5 5 of M. Joshima, and Y. Saito, Secular Variation 10 ~:I

Devonian Volcanic Rocks of Scottish 5 98 40Ar-39Ar Ages of 1(. Saito and M. Ozima, 2 71Study on Cretaceous Rocks on Paleomagnetic 8 38 40Ar-39Ar Isochron 1(. Saito and M. Ozima, 3 XI

of Magnetization of Rocks to the Changes 0 102 Ages of Six DSDP Leg 1(. Saito and M. Ozima, K-Ar 1 !IXNodules and Volcanic Rocks: A Constraint of 6 88 Nakayama, and H. Doi, S. Sakai, H. Oda, T. 16 I

Age Studies on Igneous Rocks Dredged from the 15 53 Takeuchi, H. Sakai, K. Hirooka, and A. 11 :IXMiddle Miocene Igneous Rocks In Central Eastern 13 1 Age 1(. Fujioka, and H. Sakai, K-Ar ,40 Ar-39 Ar 13 ·1X

in Nawakot Complex Rocks, Malekhu Area, 14 68 M. Funaki and H. Sakai, NRM Acquisition 13 r,!lthe Ko-Yama Metamorphic Rocks, Northeastern of 12 77 the 75,000 Years B.P. H. Sakai, Paleointensity at 16 1~

Andean Volcanic Rocks, Southern Peru 0 111 Analysis of the H. Sakai, Spherical Harmonic 6 Xof Miocene Sedimentary Rocks around Matsushima 15 47 Geomagnetic Field H. Sakai, Variation of the 6 (;1

Area in of Neogene Rocks around the Yatsuo 14 42 Variation of the H. Sakai and K. Hirooka, 12 I ~NRM of San Juan Volcanic Rocks from Colorado, of 2 20 Paleomagnetic Study H. Sakai and S. Maruyama, 11 (;X

K-Ar Age of Cretaceous Rocks from Korean and 8 46 Hirooka, T. Takahashi, H. Sakai, and T. Nakajima 10 rJ:~

K-Ar Age of the Volcanic Rocks from Kuro-Shima 5 65 Remanent H. Sakai and T. Nakajima, 6 IO~

Kyushu Study on Cenozoic Rocks from Northern 2 38 K. Hirooka, Y. Sakai, and T. Yokoyama, 4 XXthe Permian and Triassic Rocks from Okinawa-Jima, 6 126 Remanent Magnetization of Saki Welded Tuffs 6 IO~

of Cretaceous Granitic Rocks from Okushiri 0 53 of Historical Lava at Sakura-jima, Kagoshima, 4 7']of the Miocene Volcanic Rocks from Okutango Age 8 22 Recent Four Lava Flows of Sakurajima Voleano from 5 x7Investigation of Basaltic Rocks from Ponape Island, 0 106 Anisotropy of the Sambagawa Schists 5 .)-

.1

Thermomagnetic Study on Rocks from Ryoke Belt in 13 66 the South Pacific Ocean: Samoa, Rarotonga, Rurutu, 8 100of Tertiary Igneous Rocks from San'in 10 69 of Lunar and Meteorite Samples Metal Particles 1 21

Magnetization of Some Rocks from Southern Sri 16 61 Ages of Six DSDP Leg 17 Samples M. Ozima, K-Ar 1 OXStudy of the Metamorphic Rocks from Susa District, 0 33 Patterns in Terrestrial Samples and the 3 01

Data of the Cretaceous Rocks from Yamaguchi and 0 61 Inclination of Basalt Samples from Deep Sea 10 l:.?DStudy of the Cenozoic Rocks from the Amakusa 0 36 Analysis of Basalt Samples from Hole 597C 11 01

Studies of Paleozoic Rocks from the Ellsworth 13 35 of Deep Drilling Core Samples from Lake Biwa 10 :1:1of Cretaceous Granitic Rocks from the Inner Zone 11 63 Paleomagnetism of the San Juan Volcanic Field, 1 71

in Studies of Volcanic Rocks from the Island Arc 2 66 M. Kono, Origin of NRM of San Juan Volcanic Rocks 2 ~o

Studies of the Volcanic Rocks from the Line 4 122 Analyses of Japanese Iron Sands and X-Ray 4of Xenolithic Ultramafic Rocks from the Oki-Dogo 3 85 Sediments in Sangiran, Central Java 15 :H

Sr Isotopes in Volcanic Rocks from the South 8 100 Igneous Rocks from San'in District - 10 (HI

of Andesitic Rocks from the 3 51 Study H. Shibuya and S. Sasajima, A Paleomagnetic 8 !):lStudy of the Cenozoic Rocks from the Magnetic 10 134 Study H. Shibuya and S. Sasajima, A Paleomagnetic 6 121of Cretaceous Granitic Rocks in Eastern Chugoku, 8 40 Study Y. Otofuji and S. Sasajima, Experimental 4 ;1:\

of Late Precambrian Rocks in Malawi and 6 75 T. Katsura, Impure S. Sasajima, J. Nishida, and 3 ISedimentary and Volcanic Rocks in Northern Chile 10 112 of 1. Katsura, and S. Sasajima, Note on Effects 6 ,10Sedimentary and Volcanic Rocks in Northern Chile 10 120 1. Katsura and S. Sasajima, Note on the 8 Gi

to Cretaceous Sedimentary Rocks in Southern Part of 12 51 Y. Otofuji, and S. Sasajima, On the 5 2,of Cretaceous and Neogene Rocks in the Chubu Area 13 12 J. Nishida and S. Sasajima, On the 2 10

of the Paleozoic Rocks in the South 10 85 of 1. Katsura,' and S. Sasajima, Origin of Decay 8 (ilPaleomagnetism of Miocene Rocks in the Western Area 12 59 Otofuji, Y. Maeda, and S. Sasajima Paleomagnetic 10 :1:1Japan of Chichi-Shima Rocks of Bonin Islands, 10 137 and K.D. Min, and S. Sasajima, Paleomagnetism 8 ,j(;

K-Ar Ages of Volcanic Rocks of Daruma and Ida 10 50 of J. Nishida, and S. Sasajima, Paleomagnetism 6 1:\0Paleomagnetism of Igneous Rocks of Late Cretaceous 0 41 of Red H. Shibuya and S. Sasajima, Paleomagnetism 10 Ri'the Studies on Volcanic Rocks of Seamounts from 13 48 Event as Revealed in S. Sasajima, Possible Blake I ·17

Study of Precambrian Rocks of Sri Lanka in 14 86 K. Maenaka and S. Sasajima, Preliminary 12 :IXto Early Paleozoic Rocks of Tansen Area, 13 39 Chun, 1(. Maenaka, and S. Sasajima, Preliminary L. 8 0

Paleozoic and Mesozoic Rocks of the Billefjorden 15 64 K. Hirooka, Y. S. Sasajima, S. Nishitnura, 5 7:\Activities of Granitic Rocks with Geomagnetic 0 27 and F. Y. Otofuji, S. Sasajima, S. Nishimura, 6 (;9

and the Timing of Its Rotation Japan Block 15 56 and K. Hirooka, Blake S. Sasajima, S. Nishimura, 6 00N. Niitsuma, Galactic Rotation and Geomagnetic 1 130 Paleomagnetism of the S. Sasajima, Tertiary 4 lOX

for Pleistocene Clockwise Rotation in the Oiso 15 35 Hirooka, Suparka, S. Sasajima, Y. Otofuji, K. 5 101Miocene Counter-Clockwise Rotation of Northeast 11 45 On the Self-Reversal S. Sasajima and J. Nishida, 2Japan to the Time of the Rotation of Northeast 15 47 Characteristic S. Sasajima and M. Torii, 10 xo

Post-Oligocene Tectonic Rotation of Southeast 13 15 Preliminary S. Sasajima and M. Torii, 6 I~(;

River Area - Clockwise Rotation of Southwest Go 9 41 A. Hayashida, S. Sasajima, and T. 5 !)[,

Amount of Clockwise Rotation of Southwest 13 6 T. Nishitani and S. Sasaki, Measurement of 15for Rapid Clockwise Rotation of Southwest 10 77 Signals from T. Sato, Bleaching of ESR 10 7

and A. Dharma, Clockwise Rotation of Sumatra in 10 100 Resonance Dating of T. Sato, Electron Spin 8 8f,K. Koga, Counterclockwise Rotation of Tsushima and 12 44 Kobayashi, Progress T. Sato, N. Kawai, and K. 4 $):,

Y. Itoh, Differential Rotation of the Eastern 13 12 Spectral Analysis of T. Sato and K. Kobayashi, 6 J(i

Isezaki, and K. Yaskawa, Rotation of the N. 14 72 Variation of the T. Sato and 1(. Kobayashi, 6 ·11Y., Otofuji, Clockwise Rotation of the South 14 38 Paleomagnetic Study of Sawadani Greenstones in 11 HI{

- Further Evidence for Rotational Motion of 10 69 of the Sambagawa Schists Anisotropy 5 27A. Hayashida, Timing of Rotational Motion of 12 33 of Remanent Magnetism of Scottish Devonian Lava 5 2!)

from the Nevado Del Ruiz, Colombia 14 12 Paleointensity Studies of Scottish Devonian and 5 oxOcean: Samoa, Rarotonga, Rurutu, and Marquesas 8 100 Seamounts from the Japan Sea on Voleanic Rocks of 13 4X

Thermal History of the Ryoke Belt by Fission 11 103 from the Philippine Sea Core Collect.ed 4 0Study on Rocks from Ryoke Belt in 13 66 in the Philippine Sea Anomaly Lineations 5 Ill{

Island in the South Ryukyu Arc Miyako-Jima 16 44 Part of the Japan Sea - the Southwestern 13 (;

Kinematic History of the Ryukyu Arc- Arc - 16 47 the Origin of the Japan Sea - Approach to 1 77Study on the Central Ryukyu Arc - Kinematic 16 47 Area Obtained by the Deep Sea Drilling Project, 5 III

Rotation of the South Ryukyu Arc Inferred from 14 38 Basalt Samples from Deep Sea Drilling Project of 10 120Paleomagnetism of the Ryukyu Islands and Its 4 108 Central Part of the Japan Sea During GH78-2 Cruise 15 !):\

Rocks from Okinawa-Jima, Ryukyu, Southern Japan 6 126 650 (Leg 107, Tyrrhenian Sea): Geomagnetic, Hole 15 ~x

86

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Several Tertiary Dykes inShape Opening of theShibata, K. Ono, andShibutami, Japan BrunhcsShibuya, A. Hayashida, 1.Shibuya, SeveralShibuya, ThermalShibuya and S. Sasajima,Shibuya and S. Sasajima,Shibuya and S. Sasajima,Shibuya and T. Nakajima,Shidara Dike Swarm,Shiga Welded Tuff, NaganoShikoku from the InnerShikoku Basin and DaitoShikoku, Southwest JapanShima, K. Matsumoto, M.Shimamura, ArcheomagneticShimane Prefectures, WestShimokura Dike Swarm,Shimonoseki City, WestShin'etsu-Bozu Zone, theShipboard Measurement ofShocks on RemanentShodo-Shima IslandShort Duration ofShort Note onShort Note on an NRMSignals from PlanktonicSignificance Areas,Sigura-gura Formation,Siliceous Clay RemanentSilty Sediments SecnlarSilurian-Devonian SystemSingle Crystals by theSingle Heating MethodSite of Surface· SoilsSite Surveying ofSite, and the HoloceneSites Magnetic SurveyingSix DSDP Leg 17 SamplesSize Effect on theSize and Viscous RemanentSlightly Less MagneticSlumped Marine Niitsnma,Snow Involving Rock DustsSo-called "MagneticSoils Found in aSolid under HighSolubility in LiquidSolving Kinematic DynamoSomma Lavas of HakoneSound, AntarcticaSound, AntarcticaSouth African KimberlitesSouth African KimberlitesSouth Boso PeninsulaSouth ChinaSouth China BlockSouth Fossa Magna andSouth Kitakami Mountains,South KoreaSouth Korea Peninsula -South Korea since LateSouth Pacific: EvidenceSouth Pacific Ocean: inSouth Ryukyu Arc onSouth Ryukyu Arc InferredSouth-Central YamaguchiSouth-East End ofSouthcentral YamaguchiSoutheast Hokkaido ­Southeast Hokkaido andSoutheast PacificSoutheast YamaguchiSouthern Borders ofSouthern JapanSouthern Kyushu Island,

4 Central Measurement of10 of Southwest Japan - Fan59 Ujike, M. Joshima, K.72 Epoch Discovered at35 Katsura, S. M. Torii, H.80 Archeomagnetic H.91 M. Torii, H. Oda, and H.81 A Paleomagnetic Study H.48 A Paleomagnetic Study H.11 Paleomagnetism of Red H.68 Archeomagnetism of H.47 Paleomagnetism of the38 Matsubayashi, K-Ar Age of34 Zone of Ehime Prefecture,

1 of the Ocean Sediments of10 Group in Northwestern14 Furukawa, and N. N.72 T. Nishitani and C.23 Rocks from Yamaguchi and18 Paleomagnetism of the80 Cenozoic Basalt Come from39 Boundary N. Yamashita,24 Inokuchi, and K. Yaskawa,85 Effect of Repeated6 Volcanic Belt. Part 1.9 H. Ito and S. Nishimura,

59 H. Domen, A39 Direction of H. Domen, A67 T. Sato, Bleaching of ESR40 Japan, and Its Tectonic44 Sumatra, of Welded Tuff,47 Magnetization in Deep·Sea51 Variation Recorded in

112 A Paleomagnetic Study on120 Growth of Nickel Olivine

39 Determination Using a28 Found in a Pre-Ceramic29 an Old Ironmaking Furnace42 Remains, the Cave10 of Archeological34 M. Ozima, K·Ar Ages of51 T. Nishitani, Grain15 Katsura, Magnetic Grain29 Irreversible Change to a61 Remanent Magnetization of65 Mechanisms for76 Stone" from Property of88 Magnetization of Surface40 Wave Velocities of14 Some Comments on Rare Gas72 Algebra for Automatically61 Properties of the Old

1 Beacon Group in McMurdo78 in Wright Valley, McMurdo41 Megacryst Nodules in23 Peridotites in49 Crustal Structure in the31 a Stalagmite, in Ping Le,19 Polar Wander Path for the

III Adjacent Studies in the26 Paleozoic Rocks in the10 of Cretaceous Granites in

5 Gyeongsang Supergroup in12 Japan Relative to18 Clay in Penrhyn Basin,34 Volcanic Rocks from the34 Miyako-Jima Island in the41 Clockwise Rotation of the33 Andesitic Rocks from the38 Yanai-Oshima Districts,

138 the Vicinity of Ube City,4 Tectonic Rotation of

10 Pyroclastic Deposits in33 in Easter Island, the

105 Andesites Come from the51 on the Northern and29 Okinawa-Jima, Ryukyu,1 Sakura-jima, Kagoshima,

Sea, Japan (Seto Naikai) 11Sea, Japan (Seto Naikai) 11Sea Opened?: and M. 11Sea Plate Inferred from 14Sea Plate and Northeast 15Sea and Its Relevant 10Seamount T. Yamazaki, 14Seamount in the Emperor 3Seamounts from the Japan 13Secondary Component of 5Secondary Magnetizations 14Sections 3Secular Change in 16Secular Geomagnetic 1Secular Variation Curve 12Secular Variation Sea, 11Secular Variation and 6Secular Variation in 6Secular Variation of 10Secular Variation of the 14Sediment of 11Sediment Sedimentation 1Sediment Paleomagnetism 3Sediment of Calcareous 8Sediment Core Collected 12Sediment Core Collected 4Sediment Cores Field 1Sediment by TRM 4Sediment during a Field 8Sedimentary Group 14Sedimentary Rocks 4Sedimentary Rocks around 15Sedimentary Rocks in 12Sedimentary and Volcanic 10Sedimentary and Volcanic 10Sedimentation for Young 1Sedimentological or 15Sediments Consistency of 10Sediments Geomagnetic 10Sediments Variation 11Sediments 60,000 Years 1Sediments Recorded 1Sediments? Magnetization 2Sediments Magnetic 4Sediments Magnetization 4Sediments and Depth 4Sediments Paleomagnetism 4Sediments Loam" the 4Sediments Depositional 6Sediments Collected from 6Sediments and Volcanics 9Sediments during 8Sediments in Japan 12Sediments in Japan the 6Sediments in Kinki and 3Sediments in Lake y.B.P. 10Sediments in Osaka Group 5Sediments in Sangiran, 15Sediments in the Central 13Sediments of Shikoku 5Seismo-Magnetic Phenomena 1Self-Reversal Caused by 2Self-Reversal of TRM in a 2Self-Reversed in 14Sempukuji Remains, the 6Sennan and Senpoku Hills, 2Senpoku Hills, in the 2Sequence of the Furutobe 15Series Paleomagnetism 12Series in the Outer Zone 12Serpentinite from the 10(Seto Naikai) I from 11(Seto Naikai) II: A from 11Setouchi Miocene Series 12Setouchi Volcanic Belt. 6Setting of Hokuriku 11Setting of the Chubu 12Several Archeomagnetic 11

I from the Inlandof a Core from the Inland

Torii, When Was the Japanof the Philippine

between the PhilippineSpreading of the Japan

Magnetization of ErimoChain Dredged from SuikoSea on Volcanic Rocks ofRemanent M. Torii,

and M. Yoshida, On theData in Parallel

PaleoenvironmentalT. Nakajima and N. Kawai,of a Standard Geomagnetic

Japan (Seto Naikai) II: AK. Yaskawa, Geomagnetic

Paleomagnetic Study ofM. Joshima, and Y. Saito,

Inokuchi, and K. Yaskawa,Fine Magnetic Grains in

for Young Looseof Lake Biwa

Microfossils in Deep·Seafrom Paleomagnetism of a

Minerals in the Deep-SeaIntensity in Deep·Seathe NRM Intensity of

Reversal of Remanence inof the Kobe

of Slumped MarinePaleomagnetism of Miocene

of Permian to CretaceousStudy of Cretaceous

Rocks Study of JurassicK. Yaskawa, Rate of

Sea): Geomagnetic,Paleomagnetic Records in

Field from HomgeneousRecorded in Silty

Found from the Lake Biwain the Late Pleistocene

Fix in LooseStability of Deep·Sea

of ArtificialLag of NRM in Deep·Sea

of Osaka BayLate Pleistocene Volcanic

Remanent Magnetization ofRemanence of the YoungAndean Peru: Cretaceous

Magnetization in WetCurve from Giant Core

Late Pleistocene Tephrain Plio·Pleistocene

in Japan Recorded byVolcanic Ash Horizon

of Plio·PleistoceneStratigraphy of Deep·Sea

Basin and of the OceanSupplement to Studies on

and S. Sasajima, On theand J. Nishida, On the

the Andesite Pumice withArcheomagnetic Results of

in the Osaka Group,Osaka Group, Sennan and

K uroko Magnetic Polarityof the Setouchi Miocene

on the Lower CretaceousDirection of Cretaceous

the Inland Sea, Japanthe Inland Sea, Japan

Paleomagnetism of thePart 1. Study of the

Study on TectonicDistrict: TectonicMeasurements H. Shibuya,

87

Flow Occurring inand Magnetic Anomaly in

Sedimentary Rocks inAndean Volcanic Rocks,

of Some Rocks fromAges of Kimbo Volcano,

Evidence fromin Northwestern Shikoku,

in the Outer Zone offrom the Koto Rhyolite,

in the Osaka Group,Kyushu,

Pleistocene Osaka Group,between Northeast and

Some Alkaline Basalts inMiocene Muro Volcanics inRocks in Eastern Chugoku,K urosegawa Tectonic Zone,

Yamaguchi Prefecture,for Rotational Motion of- Clockwise Rotation ofof Clockwise Rotation of

Koto Rhyolites,from Westernmost Area of

Matsuda, Fast Drifting ofof Rotational Motion of

of the Eastern Part ofChert in the Tamba Belt,

to K. Yaskawa, Drift ofTorii, Paleoposition ofClockwise Rotation of

of the Billefjorden Area,Sennan and Senpoku Hills,

Archeomagnetism ofFan Shape Opening of the

Asian Blake Episode withError Angles within a

T. Sato and K. Kobayashi,a Quadrupole Type Mass

Cave by Paleomagnetism ofRecorded in a Stalagmite

Uniqueness Problem in theKono, Uniqueness of the

Analysis of H. Sakai,Analysis of the M. Kono,

Kono, Uniqueness of theChanges in the Earth's

T. Sato, ElectronContaining

A Ring-Core Fluxgate forMeasurement by Means of a

and T. Tosha, A NewY. Nishi, An Automatic

Area, SouthwestCharacteristic Back-Arc

1. Kaneoka, and K. Aoki,K-Ar,40 Ar-39 Ar Age and

Kikukawa, and K. Yaskawa,S. Zashu, and M. Ozima,

the Volcanic J. Matsuda,of and E. Takahashi, Rb,Some Rocks from Southern

of Precambrian Rocks offrom Paleomagnetism andAsh Erupted from Mount

and Y. Hamano, Noise andK. Kobayashi, Magnetic

Preriminary Report on theMagnetism of K. Momose,Variation Recorded in the

Study with aExcursion Recorded in aon Paleomagnetism of a

of Syntheticfrom Paleomagnetism of

of Construction of aTwo-Disk Dynamo System:Paleomagnetic M. Kono,

Southern Kyushu, Japan 1 47Southern Part of Boso 14 96Southern Part of Korean 12 51Southern Peru Quaternary 9 111Southern Sri Lanka 16 61Southwest Japan 11 21Southwest Japan 11 59Southwest Japan Group 12 35Southwest Japan Series 12 38Southwest Japan Pole 13 16Southwest Japan Boundary 14 27Southwest Japan 14 52Southwest Japan Tuff in 15 4Southwest Japan Area 1 92Southwest Japan to 3 1Southwest Japan Middle 6 52Southwest Japan Granitic 8 40Southwest Japan in 8 53Southwest Japan Complex, 9 24Southwest Japan - 10 69Southwest Japan - Area 9 41Southwest Japan - Fan 13 6Southwest Japan (II) 14 59Southwest Japan, Inferred 12 44Southwest Japan Inferred 16 49Southwest Japan Inferred 12 33Southwest Japan: 13 12Southwest Japan Red 6 130Southwest Japan Relative 1 77Southwest Japan and Plate 11 61Southwest Japan at Middle 10 77Southwest Spitsbergen 15 64Southwestern Japan 2 34Southwestern Japan 6 10Southwestern Part of the 13 6Special Emphasis to East 6 90Specimen 1. Muroi, 5 34Spectral Analysis of 6 16Spectrometer Gases with 2 62Speleothems - An Example 15 15(Speleothems) Collected 16 33Spherical Harmonic Kono, 3 102Spherical Harmonic M. 1 118Spherical Harmonic 6 8Spherical Harmonic 1 124Spherical Harmonic M. 2 91Spin Rate Caused by 1 114Spin Resonance Dating of 8 85Spinel (MgAI204) 4 1Spinner Magnetometer 10 1Spinner Magnetometer NRM 5 40Spinner Magnetometer: 6 22Spinner Magnetometer with 16 24Spitsbergen Billefjorden 15 64Spreading of the Japan 10 80Sr Isotope Studies of 6 97Sr Isotope Studies on 13 48Sr Isotopes in _Volcanic 8 100Sr Isotopic Studies of 2 66Sr Isotopic Studies of 4 122Sr and 40Ar/39Ar Analyses 3 85Sri Lanka of 16 61Sri Lanka in View of 14 86St Tibet as Inferred 16 38St. Helens, U.S.A. 8 57Stability of Ag-AgCI 12 94Stability of Deep-Sea 4 29Stability of Natural 4 36Stability of Remanent 5 25Stable Magnetic Remanence 6 14Stalagmite Paleoclimatic 11 16Stalagmite (Speleothems) 16 33Stalagmite, in Ping I.e, 15 21Stalagmites 14 7Stalagmites in Japan 14 18Standard Geomagnetic 12 1Statistical Properties 14 97Statistics of 6 151

1. Estimation ofAreas, Japan - Present

Determined by theof So-called "Magnetic

Yamazaki, PaleomagneticMagnetic Anomaly, Crustal

and T. Nagao, CrustalBoso Study of Crustal

Epoch and the Fineon the Layered

M. Joshima, Rock Magneticfrom Paleomagnetic

a Data Base for FutureM. Koyama, Paleomagnetic

and K. Aoki, Sr IsotopeM. Yoshida, Paleomagnetic

and Paleointensityand M. Ozima, Sr Isotopic

Central Japan - K-Ar Ageand T. Nagata, Magnetic

and L. Ocola, GeophysicalJ. Matsuda, Sr Isotopic

M. Yuasa, 40Ar-39Ar Age- Supplement to

F. Hehuwa Paleomagneticof Ar Age and Sr IsotopePreliminary PaleomangeticHayashida, Paleomagnetic

M. Kono, PaleomagneticHirooka, Archaemagnetic

of Red Cherts: A Caseon Paleo/Rock Magnetic

and H. Ito, PaleomagneticBaba, A Magnetratigraphic

M. Kono, PaleomagneticJapan: Paleomagnetic

and R. Morijiri,X. Zheng, PaleomagneticK. Yaskawa, Preliminary

on a Paleo/Rock MagneticKinoshita, Paleomagnetic

Yokoyama, Paleomagneticfrom Paleomagnetic

S. Ishida, PaleomagneticS. Sasajima, PreliminaryVitanage, Paleomagnetic

Maruyama, PaleomagneticK. Heki, Paleomagnetic

Muneoka, A Paleomagneticon Paleo/Rock Magnetic

Tokieda, A PaleomagneticOn the Thermomagnetic

On a Paleo/Rock MagneticY. Tatsumi, Paleomagnetic

Report on PaleomagneticReport on Paleomagnetic

Y. Otofuji, PaleomagneticS. Sasajima, Experimental

H. Domen, ThermomagneticSasajima, A Paleomagnetic

M. Torii, PaleomagneticSasajima, A Paleomagnetic

District: PaleomagneticY. Otofuji, Paleomagnetic

Preliminary PaleomagneticGrowth - An Approach to

and PaleoclimaticGreenstones in Jurassic

of Cations between TwoTRM in a Highly OxidizedVariation of One-Axis T.Kobayashi, Detailed T.Kobayashi, Magnetic T.T. Akimoto, Y. Onda, S.The Volumetric N.

Y. Fujiwara and R.a Mugearite Dredged fromthe Western and Northern

Statitical EerrorsStatus and a Data BaseStepwise De- andStone" from Ii-no-UraStratigraphy of Deep-SeaStructure and Matsuda,Structure and MagneticStructure in the SouthStructure of theStructure of the MantleStructures of OceanicStudies Islands IuferredStudies Status andStudies in the SouthStudies of Mafic andStudies of Paleozoic audStudies of ScottishStudies of Volcanic RocksStudies of YatsugatakeStudies of the BocaiuvaStudies of the CentralStudies of the VolcanicStudies on Igneous RocksStudies on TemperaturesStudies on Sumatra andStudies on Volcanic RocksStudies on the PermianStudy and Fission-TrackStudy in Andean Peru:Study in Hokuriku K.Study in the InuyamaStudy of Andesites fromStudy of CretaceousStudy of Cretaceous- T.Study of Cretaceous audStudy of Cretaceous andStudy of CrustalStudy of Eastern Tibet -Study of Geomagnetic andStudy of Holocene BasaltStudy of Jurassic H.Study of "Kanto Loam"Study of Oligocene toStudy of Osaka Group andStudy of PaleomagnetismStudy of PrecambrianStudy of Sawadani and S.Study of SecularStudy of the Cenozoic H.Study of the CenozoicStudy of the Ibaragi K.Study of the Ko-YamaStudy of the MetamorphicStudy of the SetouchiStudy on Cenozoic RocksStudy on Cretaceous RocksStudy on Miyako-Jima andStudy on Y. Otofuji andStudy on Rocks from RyokeStudy on Shibuya and S.Study on Tectonic SettingStudy on Shibuya and S.Study on Y. Itoh, M.Study on the Central andStudy on the LowerStudy the Planet ItsStudy with a StalagmiteSubduction Complex, SWSublatticesSubmarine Basalt ofSueishi, IntensitySueishi, N. Kawai, and K.Sueishi, N. Kawai, and K.Sugihara, T. Furuta, audSugiura and T. Nagata,Sugiyama, Post-OligoceneSuiko Seamount in the ofSulawesi, East Indonesia

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Kume,and

On the Possibility ofSigura-gura Formation,

Paleomagnetic Studies onClockwise Rotation of

for the Paleoposition ofH. WahyonoM. Hyodo, W.

y. Otofuji, K. Hirooka,Peninsula - Gyeongsang

and High Temperatures ­Remanent Magnetization of

Report on the MagneticH. Tanaka, Magnetic

and H. Tanaka, MagneticMetamorphic Rocks from

M. Ryodo, W. Sunata, E.E.and K. Yomogida, Magnetic

of On the Magnetism ofHigh-Temperature

Variation on InitialKatsura and S. Yoshida,Along the Indus-Zangbo

Kume, Remanent K.H. Ito, K. Tokieda, K.K. Hirooka, Suparka,

the K. Ibaragi, and R.A. Hayashida and H.

Duration of a Dikeof the Ashitaka Dike

An of the Shidara DikeAn of the Shirnokura Dike

of the Fudeshirna Dikeof Neogene Ocros Dike

Field in a CircularRemanent Magnetization ofRikitake Two-Disk Dynamo

on Triassic-Jurassicon Silurian-Devonian

B.J.G. Upton, Noble GasI. Kaneoka, Noble Gas

Intensity of Sediment bydue M. Kono, Changes inthe Directions of CRM and

On the Self-Reversal ofH. Tanaka and K.

Katsura, S. Yoshida, T.Thermal History of T.Nagata, M. Funaki, I.the Cretaceous Rock from

Kinoshita, Y. Onuki, A.Dating in Yanagawa and

Natsuhara, K. Yaskawa, M.T. K. Hirooka, T.Kaneoka, S. Zashu, and E.Hirano, M.High I. Kaneoka and N.

I. Kaneoka and N.Upton, I. Kaneoka, N.Possible I. Kaneoka, N.Rare Gas Isotopic N.Magnetosratigraphy of K.

Sakai, K. Hirooka, and A.I. Kaneoka, K. Notsu, Y.

Permian Red Chert in theM. Kono and H.

of Paleointensity H.Paleointensities in H.Paleointensities H.Partial M. Kono and H.Hamano, A. Horiguchi, H.Surveying of H.

N. Oshirnan and H.from the Two Dated H.of the Geomagnetic H.Paleointensities in H.Paleomagnetic H.A Geomagnetic H.Furnace for Themal H.Analysis of the H.

Sumatra Being Part of 5 104Sumatra, Indonesia Tuff, 9 1Sumatra Island: On the 5 104Sumatra in Quaternary 10 100Sumba Island, Indonesia 6 69Sunata, E.E. Susanto, and 15 31Suparka, Suwijanto, and 5 104Supergroup in South Korea 8 46Supplement to Studies on 1 26Surface Soils Found in a 15 11Survey in Niue Island 6 36Surveying of 8 81Surveying of an Old 6 7Susa District, of the 9 33Susanto, and H. Wahyono, 15 31Susceptibility Anisotropy 8 75Susceptibility Anisotropy 5 27Susceptibility Meter 16 20Susceptibility by Using 16 20Suspension Method: I. 11 80Suture between In Zone 14 78Suwa, H. Ito, and S. 3 75Suwa, and S. Kume, 6 75Suwijanto, and F. Hehuwa 5 104Suzuki, Paleomagnetism of 14 31Suzuki, Preliminary 15 64Swarm of the Activity 8 17Swarm Paleomagnetism 9 9Swarm, Central Japan - 8 28Swarm, Northeast Japan - 8 17Swarm, Oshima Island, 11 26Swarm near Ayacucho, 10 105Symmetric Coil Magnetic 8 89Synthetic Stalagmites 14 7System: Statistical The 14 97System in Inuyama Area, 6 121System in Kurosegawa 8 53Systematics in Lavas and 11 107Systematics in the 14 105TRM to Normalize the NRM 4 39TRM and ARM in a Basalt 12 72TRM in Some Andesitic of 5 5TRM in a Highly Oxidized 2 5Tachibana, A Geomagnetic 6 38Tagami, Y. Otofuji, Y. 10 33Tagami and S. Nishimura, 11 103Taguchi, J. Donon, and T. 14 1Taikazan District, of 9 49Taira, T. Ui, and L. H. 9 66Takadate Area, Northeast 16 51Takagi, K. Ikeguchi, and 2 28Takahashi, H. Sakai, and 10 53Takahashi, Rb, Sr and I. 3 85Takai, M. Miyachi, and 1. 11 21Takaoka, Excess 129Xe and 4 139Takaoka, Rare Gas 6 88Takaoka, and B.J.G. 11 107Takaoka, and K. Aoki, 12 89Takaoka and M. Ozima, 4 144Takemura and M. Torii, 5 69Takeuchi, Paleomagnetic 11 38Takigami, K. Fujioka, and 13 48Tamba Belt, Southwest of 6 130Tanaka, Analysis of the 10 9Tanaka, Field Dependence 5 18Tanaka, Four 6 30Tanaka, Geomagnetic 5 95Tanaka, Influence of 3 10Tanaka, M. Kono, and Y. 12 94Tanaka, Magnetic 8 81Tanaka, Magnetic 6 7Tanaka, Paleointensities 6 27Tanaka, Paleointensities 5 87Tanaka, Three 6 25Tanaka and H. Tsunakawa, 15 56Tanaka and K. Tachibana, 6 38Tanaka and M. Kono, A 2 24Tanaka and M. Kono, 10 16

Origin of NRM of San H.Paleomagnetism of the H.

T. Nishitani, H.T. Nishitani and S.

Early Paleozoic Rocks ofStudy of M. Torii and Y.

Partial Pressure ControlPrinciples and

the Narrow Evidence forSugiyama, Post-Oligocene

Paleomagnetic Study onChubu District:

Areas, Japan, and ItsSystem in Kurosegawa

High Pressures and HighJapan Recorded in Ontake

of the Late PleistoceneIdentification ofIdentification ofIdentification of

Fractionation Patterns inReversals during Late

of Columbia RiverMeasurement of Several

Permian Porphyllites andfrom Paleomagnetism ofof the S. Sasajima,Determination of the Late

Properties of LamellarDetermined by the

by a ModifiedTanaka, Analysis of the

M. Kono, Analysis of theM. Kono, A Furnace for

Spinner Magnetometer withDharma, and T. Yokoyama,

Tagami and S. Nishimura,H. Oda, and H. Shibuya,

H. Domen, A Short Note onElectron Microprobe andDomen, Progress Note on

of Tholeiitic H. Momose,of Preliminary Report onof the H. Domen,

Magnetic Phase in theFerromagnetic K. Momose,of the M. Yoshida,of H. Domen, Onof an H. Domen, Onthe H. Domen, On theRocks from H. Domen,

of Pyroclastic Flow byPressure of Oxygen on

Zone of T. Yamazaki,Analysis of

Magnetization Caused bythe Study of Eastern

Change in Ch'i-Lin-Ts'o,Approach to Possible

H. Ito and K. Tokieda,Japan Block and the

Motion of A. Hayashida,of Titanomagnetite lind

Titanomagnetite andProperties of x = 0.5

Remanent Magnetisms ofM. Joshima,Oxidation of

and T. Katsura, ImpureMagnetic Properties of

S. K. Hirooka, C.Quternary Deposits in the

Sediments in Kinki andRecord of H. Ito and K.Study of H. Ito and K.

K. Hirooka and K.H. Ito, K.

H. Ito and K.

Tanaka and M. Kono,Tanaka and M. Kono,Tanaka, and T. KatsllraTanoue, PaleomagneticTansen Area, Lesser t.oTatsumi, PaleomagneticTechniques Using Ox)'genTechniques Magnetometer:Tectonic Deformation ofTectonic Rotation of n.Tectonic Setting ofTectonic Setting of theTectonic SignificanceTectonic Zone, SouthwestTemperatures - underTephra, Ina, CentralTephra Sediments in JapanTephras by MagneticTephras by MagneticTephras by MagneticTerrestrial Samples andTertiary FieldTertiary Basalt inTertiary Dykes in CentralTertiary Granodirites onTertiary Igneous RocksTertiary PaleomagnetismTertiary and QuaternaryTetrataenite in TolucaThellier MethodThelliers' MethodThelliers' Method of H.Thelliers' Method of andThemal DemagnetizationThermal DemagnetizationThermal DemagnetizationThermal History of theThermal Variation onThermo-Magnetic and X-RayThermomagnetic AnalysisThermomagnetic AnalysisThermomagnetic AnalysisThermomagnetic AnalysisThermomagnetic AnalysisThermomagnetic CurveThermomagnetic Curves ofThermomagnetic PropertiesThermomagnetic PropertyThermomagnetic Propert.)'Thermomagnetic Study ofThermomagnetic Study onThermomagnetic andThermoremanent PartialThickness of the Lock-InTholeiitic BasaltThunderbolts Found inTibet ~ Deformation ofTibet as Inferred fromTilting Movements ofTilting of HokkaidoTiming of Its RotationTiming of Rotat.ionalTitanomaghemiteTitanomaghemite Joshima,TitanomagnetiteTitanomagnetite andTitanomagnetite andTitanomagnetitesTitanomagnetitesTitanomagnetites KatsuraTobira, T. Yokoyama, andTokachi District, toTokai DistrictTokieda, A Paleomagnet.icTokieda, A PaleomagneticTokieda, Archeomagnet.icTokieda, IC Suwa, and S.Tokieda, Paleomagnetism

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U.S.A. Ash ErupledUbe Cit.y, SouthcentralUeno, ChemicalUeno, Ie Hayashi, and M.Ueno, M. Nedachi,Ueno, Opaque Minerals inUeno, PaleointensityUeno, PaleomagneticUeno and M. Kono,Ueno and M. Nedachi,Ueno, and Y. Onuki,Ui, Paleomagnetism ofUi, and L. Ocola,Ujike, Paleomagnetism andUltramafic InclusiousUltramafic Nodules andUltramafic Rocks from theUltrasonic Wave and H.Uniqueness Problem in theUniqueness of theUniqueness of theUniversity MeasuredUniversity, 1980-1985Upton, Noble GasUsing Alternating FieldUsing AutomaticUsing Magnetic DipoleUsing Marine andUsing Oxygen PartialUsing VLBI NetworkUsing a Single HeatingVLBI NetworkValley, McMurdo Sound,Variation Curve fromVariation Recorded inVariation Recorded in theVariation and K-Ar AgesVariation in JapanVariation in JapanVariation in the RecentVariation of GeomagneticVariation of One-Axis ARMVariation of theVariation of theVariation of theVariation of theVariation on InitialVariations of GeomagneticVelocities of Solid underVicinity of Ube City,View of GondwanaViscous RemanentVitanage, NaturalVitanage, PaleomagneticVolcanic PaleomagnetismVolcanic Activity in theVolcanic Activity in theVolcanic Ash Erupted frolllVolcanic Ash HorizonVolcanic Ash Layer in theVolcanic Ash Layer withVolcanic Ash Layers inVolcanic Ash Layers inVolcanic Belt. Part 1.Volcanic Field, Colorado,Volcanic Rocks StudiesVolcanic Rocks: AVolcanic Rocks, SouthernVolcanic Rocks fromVolcanic Rocks fromVolcanic Rocks fromVolcanic Rocks from theVolcanic Rocks from theVolcanic Rocks from theVolcanic Rocks inVolcanic Rocks inVolcanic Rocks of DarumaVolcanic Rocks of Ar Age

from Mount St. Helens,from the Vicinity of

Composition of H.Nedachi, Magnetic H.Y.Urashima, K. H.Hydrothermal H.

M. Kono and N.Evidence of the H.Determination of N.Opaque Mineralogy and H.

M. Kono,N.Hamano, M. Kono, and T.

Y. Onuki, A. Taira, T.K. Shibata, K. Ono, and

Studies of Mafic andGas Isotopes in Hawaiian

Analyses of XenolithicFujisawa, Measurements ofSpherical M. Kana,Spherical M. Kono,Spherical M. Kono,

and Compiled in OsakaConducted by Chiba

N. Takaoka, and B.J.G.of Paleointensity Methods

Initial Susceptibility byErrors in Analyses of NRM

Study of Osaka GroupThemal Demagnetization

Plate Kinematics byIntensity Determination

Plate Kinematics by UsingComplex in Wright

Geomagnetic SecularNaikai) II: A SecularGeomagnetic Secular

Geomagnetic Paleosecularthe Holocene Paleosecularduring Study of Secular

Secular Geomagneticand Y. Saito, SecularT. Sueishi, Intensity

and K. Yaskawa, SecularGeomagnetic H. Sakai,T. Sato and K. Kobayashi,

H. Sakai and K. Hirooka,and H. Shibuya, Thermal

K. Kobayashi, DetailedHigh of Ultrasonic Wave

Serpentinite from theRocks of Sri Lanka in

Magnetic Grain Size andM. Yoshida, and P.W.M. Yoshida, and P.W.

and K-Ar Ages of HimejiDeccan of about 80 M.Y.

S. Kawachi, PleistoceneMount St. Analysis ofSediments in of KomyoikeOsaka of a Water-Laid

Polarity Episode in afrom the Water-Laid

the on the Water-LaidStudy of the Setouchi

U.S.A. of the San Juanof Scottish Devonian

Ultramafic Nodules andand Quaternary Andean

Origin of NRM of San Juanand K-Ar Age of the

Track Age of the MioceneSr Isotopic Studies of

Isotopic Studies of theYaskawa, Sr Isotopes in

Northern Sedimentary andJurassic Sedimentary and

Kinoshita, K-Ar Ages ofand Sr Isotope Studies on

Tokieda, Paleomagnetism 2 59Tokieda, Tilting of 2 54Tokieda, and K. Hirooka, 3 110Tokieda, and Y. Notsu, A 6 113Tokieda, and Y. Notsu, 8 40Tokieda, and Y. Notsu, 6 58Tokoname Group in Chita 3 36Tokuyama City, Yamaguchi 9 49Tokuyama, and H. Ito, 11 63Toluca Iron Meteorite of 12 83Tonosaki, M. Homma, 8 106Tonouchi and K. 6 107Tori!, A. Dharma, and T. 9 1Tori!, Characteristic 10 80Tori!, H. Oda, and H. 16 20Torii, H. Shibuya, A. 10 33Tori!, Late Cretaceous 13 16Tori!, Magnetosratigraphy 5 69Tori!, N. Natsuhara, K. 2 28Tori!, Paleomagnetic 10 77Torii, Paleomagnetic 1 65Torii, Paleomagnetic 11 51Tori!, Paleomagnetism of 6 52Torii, Paleomagnetism of 12 59Tori!, Paleoposition of 11 61Tori!, Preliminary 6 126Tori!, S. Yoshikawa, and 2 34Tori!, Secondary 5 11Tori!, T. Matsuda, and S. 8 34Tori!, Two "Events" 15 28Tori!, Westerly Deflected 13 8Torii, When Was the Japan 11 59Tori!, and A. Hayashida, 16 51Tori! and H. TSUFudome, 14 59Tori!, and K. Koga, 12 44Tori! and N. Ishikawa, 11 55Tori! and N. Ishikawa, 13 1Tori!, and N. Natsuhara, 3 24Tori!, and T. Matsuda, 12 29TorU and Y. Tatsumi, 6 105Tosha, A New Spinner 6 22Tosha, Paleomagnetic 9 56Tosha and H. Tsunakawa, 8 28Tosha and M. Kono, 6 61Total Force at the Blast 16 1Toyama Prefecture, Japan 14 42Trace Elements from the 4 155Track Age Dating 13 30Track Age of 0.12 Ma Ash 9 13Track Age of the Miocene 8 22Track Ages Obtained from 5 73Track Dating History of 11 103Transition Structure 1 53Transitions of the 3 56Translation of East Asia 14 80Transport Mechanism of 4 155Traps, India Volcanic 5 81Triassic Rocks from 6 126Triassic-Jurassic System 6 121Tsunakawa, Paleomagnetic 15 56Tsunakawa, Paleomagnetism 8 28Tsunakawa, Paleomagnetism 8 17Tsunakawa, and Y. Hamano, 9 9Tsurudome, Paleomagnetic 14 59Tsushima Islands, 12 44Tuff, Nagano Prefecture, 3 79Tuff, Sigura-gura 9 1Tuff in Pleistocene Osaka 15 4Tuffs Magnetization 6 102Turbulent Motion in the 2 84Two-Disk Dynamo System: 14 97Two-Disk Dynamo and 13 71Type Mass Spectrometer 2 62Tyrrhenian Sea): Chron 15 28U.S.A. from Harding 12 6U.S.A. of the San Juan 1 71U.S.A. San Juan Volcanic 2 20U.S.A. River Tertiary 4 114

of H. Ito and K.Hokkaido H. Ito and K.N. Kawai, T. Nakajima, K.Paleomagnetic H. Ito, K.Paleomagnetic H. Ito, K.

H. Ito, K.of Magnetostratigraphy of

from Taikazan District,Y. Nishiyama, A.

Lamellar Tetrataenite inY. Igarashi, and T.

Kobayashi, Magnetic S.Yokoyama, Thermal M.

S. Sasajima and M.Shibuya, Thermal M.Hayashida, I. M.

K. Fukuma and M.of K. Takemura and M.Yaskawa, T. Nakajima, M.Evidence for Rapid M.Investigation of a M.Study on Y. Itoh and M.Middle Miocene Muro M.

T. Nakajima and M.Y. Otofuji, and M.

S. Sasajima and M.M. Itihara, M.Component of RemanenM.Ishida, Natural M.

J.E.T. Channell and M.N. Ishikawa and M.

Sea A. Hayashida, and M.Paleomagnetic H. Oda, M.Paleomagnetic Results M.

N. Ishikawa, M.Anomalous Magnetic M.Paleomagnetic M.Nakajima, K. Yaskawa, M.the Study on Y. Itoh, M.Paleomagnetic Study M.

T. Nishitani, and T.Measurement of the T.Paleomagnetism o(the T.Paleointensity T.by Jump in'the Magneticaround the Yatsuo Area in

Transport Mechanism' ofNew Evidence from Fission

Layer with the FissionVolcanic and Fissionthe Results and Fission

the Ryoke Belt by Fissionof the GeomagneticRecord of Polarity

Otofuji, Large NorthwardTrace Elements M. Ozima,

Activity in the Deccanon the Permian and

A Paleomagnetic Study onH. Tanaka and H.

of the T. Tosha and H.of the K. Heki and H.Paleomagnetism of the H.Results M. Tori! and H.Westernmost Rotation ofK-Ar Age of Shiga Welded

Experiments of WeldedProperties of the Azuki

of Saki WeldedCore of Parameters of

M. Hoshi, The RikitakeM. Kono, Rikitake

Gases with a Quadrupoleat Hole 650 (Leg 107,

Lake in Interior Alaska,Volcanic Field, Colorado,

Rocks from Colorado,Basalt in Washington,

90

the Late PleistoceneCretaceous Sediments and

Peninsula of Quaternaryof Middle Miocene Muro

Lava Flows of SakurajimaFlows of the Myoko

from the HakoneOld Somma Lavas of Hakone

Ages of KimboPaleomagnetism of Daruma

Studies of Yatsugatakein the Yatsugatake

Results of Izu and HakoneRocks of Daruma and Ida

and T. Nagata, TheM. Kono, M. Ozima, and K.of E.E. Susanto, and H.China on Apparent Polar20 My Inferred from Polar

River Tertiary Basalt inof Parameters of H.Fluctuations in the H.

Matsuo, On Deficiency ofLayer Investigation of aChange Obtained from the

Paleomagnetism on theunder High of Ultrasonic

K-Ar Age of ShigaExperiments of

Magnetization of SakiJapan Collected from

the Ellsworth Mountains,the Kobiwako Group on the

from Shimonoseki City,from Okushiri Island,

Kyushu Island,Yamaguchi Prefecture,of Some Iron-Sands of

Yamaguchi Prefecture,of Yamaguchi Prefecture,

Yamaguchi Prefecture,in Yamaguchi Prefecture,Northern Kyushu Island,

Yamaguchi Prefecture,Yamaguchi Prefecture,

of Yamaguchi Prefecture,Yamaguchi Prefecture,

Westcentral Kyushu,Yamaguchi Prefecture,

and Shimane Prefectures,District, Masuda City,

Cenozoic Rocks from thefrom the Amakusa Islands,N. Ishikawa and M. Torii,

of Miocene Rocks in theAndesite Dyke from the

the Island Arc in theAges Obtained from the

of Tsushima Islands,Remanent Magnetization in

of Basement Complex inon Thermo-Magnetic and

of Kapuho Lava andand 40Ar/39Ar Analyses of

Basalt from Kasa·Yama,Kusakabe, F. Murata, S.Inokuchi, J. Matsuda, S.

Basalt at Kasa·Yama,District, Northeastern

Koyama Intrusive Complex,of Ube City, Southcentral

West Rocks, NortheasternWest South-East End ofWest from the Central

the DUuvian Deposits infrom the South-Central

Come from the SoutheastWest City, West End of

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