10. SITE 311: HAWAIIAN MAGNETIC LINEATIONS

10. SITE 311: HAWAIIAN MAGNETIC LINEATIONS

The Shipboard Scientific Party1

SITE DATA

Date Occupied: 27 September 1973 (0325)

Date Departed: 28 September 1973 (2242)

Time on Site: 43.3 hours

Position: 28°07.46'N, 179°44.25'E

Water Depth: 5775 corrected meters (echo sounding)

Bottom Felt With Drill Pipe At: 5780 meters below rig floor

Penetration: 37 meters

Number of Holes: 1

Number of Cores: 5

Total Length of Cored Section: 37.0 meters

Total Core Recovered: 19.0 meters

BACKGROUND AND OBJECTIVES

Site 311 was selected as a place where two importantobjectives might be reached by a single hole: to date theyoung end of the sequence of Mesozoic magnetic rever-sals and to date the episode of volcanism of a part of theHawaiian Ridge northwest of Midway Islands. Thetrend of the Hawaiian set of magnetic anomalies inter-sects the trend of the Hawaiian Ridge at about the Inter-national Dateline. The site had been assigned to Leg 33,but in the readjustments of scheduling Pacific dates andports that resulted from the delay in the installation ofthe heave compensator, the site was reassigned to Leg32.

Larson and Chase (1972) used a magnetic-reversalblock model based on the Phoenix lineations to cor-relate the Phoenix and Japanese lineations with theeastern portion of the Hawaiian lineations (anomaliesM-l to M-10). Site 311 on anomaly M-2 on theHawaiian lineation pattern will test the validity of thiscorrelation. If this correlation is substantiated, Site 311may be an important point for the calibration of theyoung end of the Mesozoic reversal time scale. This timescale, derived by Larson and Pitman (1972), predicts a

'Roger L. Larson, Lamont-Doherty Geological Observatory,Palisades, New York (Co-chief scientist); Ralph Moberly, HawaiiInstitute of Geophysics, Honolulu, Hawaii (Co-chief scientist); DavidBukry, U.S. Geological Survey, La Jolla, California; Helen P. Fore-man, Oberlin College, Oberlin, Ohio; James V. Gardner, Scripps Insti-tution of Oceanography, La Jolla, California; John B. Keene, ScrippsInstitution of Oceanography, La Jolla, California; Yves Lancelot,Lamont-Doherty Geological Observatory, Palisades, New York;Hanspeter Luterbacher, Esso Production Research—European,Begles, France; Monte C. Marshall, U. S. Geological Survey, MenloPark, California; Albert Matter, Universitat Bern, Bern, Switzerland.

HAKODATE J*l

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HAWAIIAN ISLANDS

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130° 140" 150' 160° 170° 180" -170" -160" -150"

late Barremian to early Aptian basement age for Site311, about 110-115 m.y. The results from this site alsocan be checked against a recent compilation of continen-tal rock magnetic data for the Cretaceous (Irving andCouilliard, 1973). They predict an interval of normalmagnetic polarity from 82 to 109 m.y. that occurred justafter the late Mesozoic reversal sequence. The age of M-2 should be just older than the old end of their long nor-mal magnetic interval.

This study will also test the hypothesis of Larson andPitman (1972), that the Late Cretaceous period betweenthe "Cenozoic" and Mesozoic reversals was the time ofa worldwide increase in sea-floor-spreading rates. Thispulse has been evoked to explain a simultaneous pulse inbatholithic emplacement around the Pacific basin (Lar-son and Pitman, 1972), the worldwide transgression ofepicontinental seas during the Late Cretaceous (Haysand Pitman, 1973) and the Mesozoic orogenic history ofJapan (Uyeda and Miyashiro, 1974). It has been notedby Irving and Couilliard (1973) to coincide with theCretaceous normal interval, a coincidence which may bethe most obvious aspect of a more general phenomenonthat worldwide spreading rates are, in general, inverselyproportional to the frequency of geomagnetic reversals(W. C. Pitman, III, personal communication).

Although the general progression of volcanismtoward the southeast along the Hawaiian Archipelagohas been recognized for over a century, there has beengreat current interest in the problem brought about bythe stimulus of Wilson's (1963) hypothesis of the originof linear volcanic chains by the movement of the litho-sphere over a magma source, by the radiometric datingof Hawaiian volcanic rocks (McDougall, 1964; Funk-houser et al., 1968), by geophysical surveys by ScrippsInstitution of Oceanography (Shor, 1960; Normark andShor, 1968) and the Hawaii Institute of Geophysics(Malahoff and Woollard, 1968; Furumoto et al., 1971),and the drilling on Midway Islands (Ladd et al., 1967).

295

SITE 311

The archipelagic apron of the Hawaiian Ridge shouldinclude a sedimentary record of the episode of vol-canism that built the adjacent seamounts of the chain.The interpretation of sediments recovered at Site 165,drilled west of the Line Islands in their apron, provideddates for the volcanism of a nearby seamount, fromfossils within the turbidites composed of volcanic rockfragments that make part of the total section. Someevents of the history of the seamount near Site 165 sub-sequent to its formation by volcanism were also dis-closed by study of the fossils and sediment types in theturbidites above the part dominated by volcanic debris.

On Midway, where two core holes were drilled by arig on a barge, the volcanic foundation of the atoll isabout 18 m.y. old (M. A. Lanphere and G. B. Dalrym-ple, personal communication in Grommé and Vine,1972). The seamount farthest west of Midway is a largeunnamed one whose peaked summit (at about 270 m) isnear 28°50'N, 179°35'W. Its apron covers the youngestMesozoic magnetic anomaly. The seamount apparentlydoes not have drowned reefs on its slopes, so Site 311may not have any record of the history of the seamountafter its time of origin, but the site is expected to providethe time of volcanism.

Among the variations of Wilson's theory, one pro-posed by Morgan (1971, 1972) is that melting anomalies,or "hot spots," exist in the earth's mesosphere and vol-canic chains are the record of the passage of the litho-spheric plates over the mesosphere. Morgan (1971,1972) also proposed that the hot spot that formed theHawaiian chain and is still active, previously had form-ed the Emperor Seamounts before a change in the rela-tive motion of the Pacific plate and the mesosphere.However, perhaps the volcanism results from the pro-gressive release of pressure (Jackson et al., 1972),perhaps the hottest parts of the asthenosphere is incounterflow toward mid-ocean ridges under thelithosphere (Moberly and Khan, 1969) so thatlithosphere-to-mesosphere motion cannot be measuredby dating volcanism, or perhaps the mechanisms ofvolcanism and motion are ones not yet proposed. Theprogression of dates between the active Hawaiianvolcanoes and Midway is nearly but not exactly linear,but a linear rate cannot be continued to the next placenow known, Kδko Guyot in the southern EmperorSeamounts, 50 m.y. at our Site 308. The geometry anddates of Pacific plate motion (Clague and Jarrard, 1973)and of circumpacific events in the Cenozoic (Jackson etal., 1972) have been related to Hawaiian-Emperor rates.A major objective of Site 311 is to gain an additionaldate beyond Midway for the testing of these and othertheories.

Beneath the turbidite debris from the Hawaiian Sea-mounts should lie the Mesozoic and early Cenozoicsediments that were deposited on the Pacific plate beforethe development of the Hawaiian chain in this area. Site311 should have been formed south of the equator, sothese sediments should have recorded both the sub-sidence from original ridge-crest elevations, and the sub-sequent passage of Site 311 across the equator. This sitecould have considerable bearing on this phase of thehistory of the Pacific plate as it is relatively isolated fromthe other old sites that are useful to this study.

The sediments at Site 311 probably contain cherts asdo the other Mesozoic locations in the western Pacificthat crossed the equator during the Cretaceous. The ageand nature of these cherts will be studied to shed light onthe equatorial transit of Site 311 and the factors in-volved in the chertification of these sediments.

The basaltic basement at Site 311 should be ridge-crest type tholeiite (commonly olivine-normative andvery low in alkalies) with pillows and hyaloclastiteswhich typify many previous DSDP basaltic sites. Theserocks should be considerably altered because of theirage and should be useful to geophysicists interested inrefraction seismology, to geochemists postulating thecomposition of subducted crust and the transfer of tran-sition elements from volcanic rocks to overlying sedi-ments, and to rock magnetists interested in the direc-tion, stability, and intensity of remnant magnetization.

OPERATIONS

We approached Site 311 (Figure 1) on magneticanomaly M-2 and the archipelagic apron of theHawaiian Seamount chain generally from the north(Figure 2). We intersected the western flank of the largeseamount about 250 km northwest of Midway Islandsand turned south-southwest to run across its archi-pelagic apron to the site. The site is located near thesouth edge of a detailed survey by Kana Keoki and justsouth of M-2 on the C. H. Davis magnetic profile (Lar-son and Chase, 1972). The Kana Keoki profile at 0814,16 July 1972, shows 0.1 sec of layered, but semitrans-parent material, overlying much darker reflectors. Wepassed over the site at full speed with our profiler show-ing only 30 meters of transparent sediment overlyingmuch more opaque material. We continued on to thesouth-southwest for another 0.5 hr in search of a betterlooking site. None appeared, so we made a WilliamsonTurn, slowed to 5 knots and returned approximately tothe original site. At 1525Z on 26 September 1973, we

Figure 1. Bathymetry in the region of Site 311 (after Chaseet al., 1971). Contour interval 200 fm uncorrected.

296

SITE 311

29°N

28° N

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Figure 2. Track chart in the vicinity of Site 311. Solidtrack is Leg 32 Glomar Challenger, dashed track is KanaKeoki, dash-dot-dot track is C. H. Davis, dot track isTasaday-J. Glomar Challenger navigation points indi-cated by open circles and annotated time/day-month.

dropped the beacon on the run in 2798 uncorrectedfathoms of water (5285 m corrected to the rig floor).

No sonobuoy was run on this site because of theshallow penetration that was achieved before breakingoff the bottom-hole assembly. We steamed directly awayfrom Site 311 toward Site 312 (Figure 3) without passingover the beacon.

It took 11 hr to reach the ocean floor after starting torun in pipe, throughout which the ship was taking 7° to10° rolls from the 1.5-2 meter long period swells gen-erated by the storm to the north that had blown us off ofHess Rise. We were forced to position the ship headingeast into the 20-mph eastern trade wind, thus putting thelong storm swells on our port beam. About 2 hr werelost running in pipe when the automatic pipe racker wasshut down for repairs.

We appeared to tag the ocean floor at 5285 metersand rotated, but did not circulate, to cut a 4-meter core.When the core was brought on deck, we discovered wehad recovered 8.1 meters of zeolitic pelagic clay. Themudline was established officially as 5280 meters,although the driller's indication of 5285 meters is at leastan equally probable estimate. It is likely that additionalmaterial was crammed into the core barrel, causing therecovered section to be apparently thicker than the realstratigraphic interval.

A second core taken directly below the first one alsoconsisted of soft zeolitic pelagic clay. Throughout thisperiod the ship was maintaining its position well, butconsiderable rolls were still being taken.

While cutting the third core, a hard layer was en-countered at 5301 meters. A small amount of penetra-tion was made in this formation, and a partial core wasrecovered that revealed a lithified, brown mudstone.Core 5 took approximately 5 hr to cut although the lastfew meters were penetrated very quickly. Core 5 is a

SITE 311

— 5 SEC

I I I I I I I 1 I I I I | I I I15 28 Sept 73 11 14 26 Sept 73

7 Kts| Speed ^9 Kts Slow| o

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Figure 3. Seismic profiler section approaching and leaving Site 311.

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297

SITE 311

lithified volcanic turbidite similar to Core 4. We ap-peared to penetrate very quickly for what should havebeen Core 6, but only the sinker bar and overshot wererecovered, and the sinker bar was badly bent. When thedrill string was weighed and the pump pressure tested, itbecame apparent that we had lost part of the bottom-hole assembly.

The drill string was pulled up in 10 hr to reveal thatwe had broken off the bottom-hole assembly at a lowerbumper-sub connection. This is the same place the as-sembly was broken at Site 309 on Köko Guyot, and thecause is the same; constant pounding of the brittle bot-tom-hole assembly on a hard formation without anylateral support. Table 1 is a summary of coring at Site311.

The correlation of seismic reflection profiles with thedrilling results shows that at this site during coring, likeSite 310 and many sites on previous legs, soft sedimentmay have filled a core barrel before it penetrated a com-plete 9 to 9.5 meters. The echo-sounding depth, cor-rected to the rig floor, was 5785 meters, which also waswhere resistance was felt as the bit apparently met thesea floor. However, as the core was virtually full whenrecovered, the top of the cored interval was listed as5780 meters, the depth when that joint of pipe was firstlowered. The 16 meters between 5785 and 5801 meters(top of hard drilling) is closer to the PDR difference andis perhaps a truer thickness for the brown pelagic clay atSite 311 than the 21 meters listed in this report. There islittle practical meaning to this evaluation at this site, notonly because the 12- and 3.5-kHz subbottom reflectionsvary by several meters over the region, but also becausethere are no useful fossils in the pelagic clay anyway. Butit does point out once again the need for a 3.5-kHzsystem and a drill-string pinger on Glomar Challengerfor sites where information about the uppermost layersis critical.

LITHOLOGIC SUMMARYThe stratigraphic section drilled at Site 311 was con-

tinuously cored down to 37 meters, the total depth of thehole. The hole was drilled in 5780 meters of water.Recovery was good in Cores 1 and 2, but was poor inCores 3, 4, and 5. The poor recovery was due to highpump pressures required by the combination of lithifica-tion and shallow hole penetration. The composition ofselected lithologies is shown in the smear slide summary(Table 2).

The section can be divided into two sedimentaryunits:

Unit 1—Zeolitic pelagic clay (0-13 m, Cores 1 and 2).Unit 2—Volcanic turbidites (13-37 m, Cores 2

through 5).

Unit 1—Zeolitic Pelagic Clay (Cores 1 and 2)This unit extends down to Core 2, Section 4, where

the top of the underlying turbidite sequence occurs. Theunit is a typical deep-sea brown, soft, zeolitic clay whichis unfossiliferous except for rare fish debris. The zeolitephillipsite is abundant and is generally in the form ofcorroded laths with rare twins. The laths range in size upto 35 µm. There is a minor amount of yellowish-greenvolcanic glass.

At the base of Core 1 the upper part of a turbiditelayer was recovered. It consists of semilithified, silt-size,cross-bedded volcanic debris. The volcanic material wasmainly well-sorted angular palagonite grains (av. 50 µm)with lesser amounts of subhedral Plagioclase and pyrox-ene (av. 40 µm to 50 µm). The palagonite has nowaltered to clay and zeolite.

Beneath this turbidite, zeolitic clay occurs down to thebasal contact of the unit. The contact is gradational dueto drilling disturbance.

Unit 2—Volcanic Turbidites (Cores 2 through 5)The upper part of this unit (13-21 m) consists of

crumbly to semilithified turbidite layers with minor in-terbeds of brown zeolitic silty clay. Core 2 has severalcomplete turbidites up to 1 meter thick. They are yel-lowish-brown in color and are generally calcareous intheir upper part, whereas the lower, coarser fraction ismore lithified. The carbonate is recrystallized calcite andcontains burrows now filled with sparry calcite.

The lower part of this unit (21-37 m, Cores 3,4, and 5)is lithified and there are no complete turbidites becauseof the poor recovery. In Core 3 a sequence of truncatedcross-beds was sampled from a turbidite, but it appearsthat the finer upper parts of each turbidite have beenwashed away. Only at the base of Core 5 is there a finelylaminated silty claystone representing the upper part ofa turbidite.

In thin section, the light brown volcanic turbiditesfrom Core 3 consist of brown palagonite, pale brownmontmorillonite, zeolite (phillipsite), basalt fragments,Plagioclase, and pyroxene grains. The clay and radiatingcrystals of zeolite form the cement as well as replacing

TABLE 1Coring Summary

Date(Sept.

Core 1973) Time

Depth FromDrill Floor

(m)

Depth BelowSea Floor

(m)

LengthCored(m)

LengthRecovered

(m)Recovery

12345

Total

2727272828

20102145234506101000

5280.0-5289.05289.0-5298.55298.5-5301.55301.5-5308.05308.0-5317.0

0.0-9.09.0-19.519.5-22.522.5-28.028.0-37.0

9.09.53.06.59.0

37.0

8.18.01.10.61.2

19.0

90843799

51.4

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Sample(Interval in cm)

Surface Seawater1-5, 144-150

TABLE 3Summary of Shipboard Geochemical Data

Depth BelowSea Floor (m)

7.5

pHPunch- Flow-

in through

8.24 8.337.69 7.57

Alkalinity(meq/kg)

2.372.32

Salinity(%o)

35.535.2

Remarks

8.347.61

CORRELATION OF SEISMIC REFLECTIONPROFILES WITH DRILLING RESULTS

The drill did not penetrate sufficiently deep for us todetermine the acoustic stratigraphy of the airgunrecords.

There is, however, a point of correlation on the 12-kHz PDR record, which shows a strong subbottomreflection over nearly all of the archipelagic apron. Thereflection also is prominent on 3.5-kHz records of otherships. In the vicinity of Site 311 the reflector is about 7or 8 fm (about 13-15 m) below the bottom (Figure 4). Itrepresents the top of the zeolite-cemented hard tur-bidites of Oligocene age.

PHYSICAL PROPERTIES

Wet Bulk Density and Porosity of Soft Sediments

The wet bulk density of the zeolitic pelagic clay andthe upper, clayey volcanic turbidites was measured withthe GRAPE. The sections measured were 2 and 5 inCore 1 and Sections 3 and 5 in Core 2. The density of thesoft, severely disturbed clay decreases from 1.42 g/cc atthe top of Core 1 to 1.24 g/cc at the top of Core 2, Sec-tion 3, and then increases to 1.30 at the base of this sec-tion. The density continues to increase in the stiff-semi-lithified, moderately severely disturbed, volcanic tur-bidites of Core 2, Section 5, increasing from 1.45 g/cc atthe top to 1.57 g/cc at the base of the section. A syringe

Figure 4. 12-kHz PDR record of subbottom reflector withthe Hawaiian archipelagic apron.

sample was taken from each of the sections measuredon the GRAPE as an independent measure of wet bulkdensity and porosity. The syringe densities and thevalues determined by the GRAPE agree, on the aver-age, within several percent. The syringe data show thatthe wet bulk density variations are due largely to porosi-ty differences. The porosity, therefore, varies inverselyas the wet bulk density increasing from about 75% at thetop of the pelagic clay to about 85% at the top of Core 2,Section 3, and then decreasing to 70% in the clayey-sandy, volcanic turbidites at the base of Core 2, Section5. The fairly sharp increase in wet bulk density ob-served in the turbidites near the base of this section maybe due, at least in part, to an increase in grain density.The porosity of these turbidites may be somewhathigher than 70%.

Sonic VelocityThe compressional wave velocity, Vp, of the soft, in-

tensely disturbed, zeolitic pelagic clay recovered at thissite is about 1.50 km/sec. The Vp in the semilithified tolithified volcanic turbidites is much higher and rangesfrom 2.2 to 2.5 km/sec in the volcanic claystone to 2.5 to3.4 km/sec in the volcanic sandstone. A summary ofphysical properties for Site 311 is found in Figure 5.

BIOSTRATIGRAPHIC SUMMARYThe sediments recovered at Site 311 are deep-sea

pelagic clays (Cores 1 and 2) and transported elastics ofvolcanic origin. Therefore, most of the samples exam-ined are barren.

Only one sample in Core 3 could be dated as early lateOligocene based on coccoliths.

Fish remains (mainly teeth) are relatively common inCores 1 and 2.

ForaminiferaThe samples examined from this site contain no strati-

graphically useful foraminifera.Small numbers of simply structured arenaceous

foraminifera ("Rhabdammina-F aunas") and fish re-mains occur in Cores 1 and 2.

CoccolithsCoccolith assemblages are present in Cores 2 to 4. In

most samples Cyclicargolithus ßoridαnus composes theassemblage and suggests only a post-Eocene age becauseof the turbidite origin of the sediment. A single samplein Core 3, Section 1, contains Dictyococcites bisectusand Sphenolithus distentus in addition to Cyclicargo-lithus floridanus. This assemblage indicates the early lateOligocene Sphenolithus distentus Zone (approximately27 to 30 m.y.)

300

SITE 311

Radiolaria

No Radiolaria were found in the five cores recoveredfrom this site. Fish teeth were found in the dark brownclay of Core 2, Section 2, and may be present through-out the dark brown clay of Cores 1 and 2.

SUMMARY AND CONCLUSIONSThe Sphenolithus distentus flora of Core 3 is early late

Oligocene in age and indicates that the archipelagicapron of this part of the Hawaiian volcanic chain wasbuilt by the middle of the Oligocene. Undoubtedly thenearby Hawaiian Seamount was the source of the debrisof fresh and palagonitized hyaloclastic glass, and lesseramounts of fresh hyaloclastic and reworked pyroclasticglass and lithic volcanic grains, because the turbiditebeds are traceable on the Glomar Challenger and KanaKeoki reflection profiles to the slopes of the seamount.

The early late Oligocene age of about 27 to 30 m.y. isa minimum one, because we did not penetrate to the in-itial volcanic turbidite beds.This age is at least 10 m.y.older than the currently accepted radiometric ages forMidway Islands. If the Hawaii-to-Midway progressionof volcanic age is extrapolated west of Midway, thepredicted age is only 2 m.y. older than Midway. In fact,the age of volcanism determined by apron drilling at Site311 is fairly close to a linear interpolation betweenMidway and Köko Guyot. We conclude that the vectorof relative motion between the Pacific plate and themelting anomaly has been constant in direction but thatthe rate was slower prior to the formation of Midway.This result also suggests that the vector change that oc-curred at the Emperor-Hawaiian "elbow" was more oneof direction than rate.

The only history subsequent to the volcanic events atthis site is the change from turbidite to pelagic sedimen-tation by Miocene time (Core 2).

Unfortunately, the loss of part of the bottom-holeassembly precluded any chance of dating the young endof the sequence of Mesozoic magnetic reversals. Figure5 is a summary of data from Site 311.

REFERENCESChase, T. E., Menard, H. W., and Mammerickx, J., 1971.

Topography of the North Pacific: Institute of MarineResources, University of California, San Diego.

Clague, D. A. and Jarrard, R. D., 1973. Tertiary Pacific platemotion deduced from the Hawaiian-Emperor chain: Geol.Soc. Am. Bull., v. 84, p. 1135-1154.

Grommé, S. and Vine, F. J., 1972. Paleomagnetism of MidwayAtoll lavas and northward movement of the Pacific plate:Earth Planet. Sci. Lett., v. 17, p. 159-168.

Funkhouser, J. G., Barnes, I. L., and Naughton, J. J., 1968.The determination of a series of ages of Hawaiian vol-canoes by the potassium-argon method: Pac. Sci., v. 22, p.369-372.

Furumoto, A. S., Campbell, J.F., and Hussong, D. M., 1971.Seismic refraction surveys along the Hawaiian Ridge,Kauai to Midway Islands: Seis. Soc. Am. Bull., v. 61, p.147-166.

Hays, J. D. and Pitman, W. C , III, 1973. Lithospheric platemotion, sea level changes, and climatic and ecological con-sequences: Nature, v. 246, p. 18-22.

Irving, E. and Couilliard, R. W., 1973. The Cretaceous normalpolarity interval: Nature Phys. Sci., v. 244, p. 10-11.

Jackson, E. D., Silver, E. A., and Dalrymple, G. B., 1972.Hawaiian-Emperor chain and its relation to Cenozoic cir-cumpacific tectonics: Geol. Soc. Am. Bull., v. 83, p. 601-618.

Ladd, H. S., Tracey, J. I., Jr., and Gross, G. G., 1967. Drillingon Midway Atoll, Hawaii: Science, v. 156, p. 1088-1194.

Larson, R. L. and Chase, C. G., 1972. Late Mesozoic evolu-tion of the Western Pacific: Geol. Soc. Am. Bull., v. 83, p.3627-3644.

Larson, R. L. and Pitman, W. C, III, 1972. Worldwide cor-relation of Mesozoic magnetic anomalies, and its impli-cations: Geol. Soc. Am. Bull., v. 83, p. 3645-3663.

Malahoff, A. and Woollard, G. P., 1968. Magnetic and tec-tonic trends over the Hawaiian Ridge. In Knopoff, L.,Drake, C. L., and Hart, P. J. (Eds.), The crust and uppermantle of the Pacific area: Am. Geophys. Union Mono. 12,p. 241-276.

McDougall, I., 1964. Potassium-argon ages from lavas of theHawaiian Islands: Geol. Soc. Am. Bull., v. 75, p. 107-128.

Moberly, R. and Khan, M. A., 1969. Interpretation of satel-lite-determined gravity anomalies: Nature, v. 223, p. 263-267.

Morgan, W. J., 1971. Convection plumes in the lower mantle:Nature, v. 230, p. 42-43.

, 1972. Plate motions and deep mantle convection. InShagam, R. et al. (Eds.), Geol. Soc. Am. Mem. 132, p. 7-22.

Normark, W. R. and Shor, G. G., Jr., 1968. Seismic reflectionstudy of the shallow structure of the Hawaiian Arch: J.Geophys. Res., v. 73, p. 6991-6998.

Shor, G. G., Jr., 1960. Crustal structure of the Hawaiian Ridgenear Gardner Pinnacles: Seismol. Soc. Am. Bull., v. 50, p.563-574.

Uyeda, S. and Miyashiro, A., 1974. Plate tectonics and theJapanese Islands: A Synthesis: Geol. Soc. Am. Bull., v. 85,p. 1159-1170.

Wilson, J. T., 1963. A possible origin of the Hawaiian Islands:Canadian J. Phys., v. 41, p. 863-870.

CORES

NO. DEPTHLITHOLOGY AGE

BIOSTRATIGRAPHIC ZONATIONFORAMINIFERA NANNOPLANKTON RADIOLARIA

POROSITY | SONIC VEL.(GRAPE)% 1.4 KM/SEC 5.4

1

- 2

- 3

4

- 5

50-

09

19.522.5

28

I37 T.D.

- V

rz3F.

Zeolitic pelagic clay

Volcanic turbidites, softto semilith.; part. calc.(very hard drilling, topat 21 m) Volcanic tur-bidites, lithified

post-EOCENE

*EARLY LATE OLIGOCENE

85

Figure 5. Summary of coring, lithology, biostratigraphy, and physical properties at Site 311.

301

oto

Site 311 Hole Core 1 Cored Interval :0.0-9.0 m Cored Interva l :9.0-19.5

FOSSILCHARACTER

CoreCatche

LITHOLOGIC DESCRIPTION

H

5YR 4/4

ZEOLITIC PELAGIC CLAY.Dominantly moderate brown (5YR 3/4)with occasional light brown (5YR 5/6)streaks. Soft and intensely disturbed.

Smear Slide at 4-100Texture(O-C-A)

CompositionClayZeolitesQuartzFeldsparHeavy mineralsVolcanic glassPalagoniteFe-oxideMπ micronodulesFish debris

ACRRRRRRRR

Minor l i t h o l o g y sampled is VOLCANICSILTSTONE recovered in Section 6 andCC. Probably part of a t u r b i d i t e layernow broken-up by d r i l l i n g . Laminated(1-10 mm) and minor cross-bedding.Moderate brown (5YR 4/4). Palagonitefragments (<l mm) and micronodules ofMn common. With minor z e o l i t i c mud.

X-rayMicaQuarPlagK-Fe

X-rayPlagAug iMagn

2-10032.9%39%17%

3.7%

6-14040.5%45.5%

5 . 2 *

ChloMontAmor

P h i lQuarAmor

4.2%

69.1%

7.6%1.2%

68.1%

FOSSILCHARACTER

CoreCatcher


5YR 3/4 with5YR 5/6 streaks

10YR 5/4and10YR 4/2

Core is deformed except where semi-lithified sediment lumps were recov-ered from the turbidite sequence.Material may be missing from betweenthese lumps. Turbidite sequence beginsin Section 4.

ZEOLITIC PELAGIC CLAY.Dominantly moderate brown (5YR 3/4)with occasional light brown (5YR 5/6)streaks. Soft and intensely disturbed.Becoming grayish brown (5YR 3/2) withdepth.

Smear Slide at 1-130Texture(O-C-A)

CompositionClayZeol i tesPalagoniteQuartzFeldsparHeavy mineralsVolcanic glassFe-oxide

ACCRR;RR

CALCAREOUS VOLCANIC SANDSTONE withminor VOLCANIC SILT and VOLCANIC CLAY.Zeolitic pelagic clay grades to avolcanic silt in Section 4. Complexseries of turbidite layers of varyingthickness (40-100 cm). Moderate yellow-ish brown (10YR 5/4), crumbly, semi-lithified. Base of turbidites morelithified and generally contain lesscalcareous material. Some calcitecemented nodules. Thin (5-10 mm)layers common. Grading good to poor.Silt and clay dark yellowish brown(10YR 4/2).

Carbon-Carbonateb-83

X-rajPhilK-FeQuar

X-rajCalcK-FePlag

(3.6-0-30)

I 3-11027.4%27.6%14.5%

1 5-8059.7%24.9%

8.2%

MontMicaPlag

MontMicaAmor

12.9%1.2%7.0%

1.2%

1.5%

5 8 . 9 %

Magn

Amor

379

in

HW

Magn 4.5%

Explanatory notes in Chapter 1

Site 311 Hole Core 3 Cored Interval:19.5-22.5 m

AGE

EARLY OLIGOCENE

ZONE

NANNOS

FORAMS

RADS

Sphenolithus distentus

FOSSILCHARACTER

FOSSIL

NRNNNNFF

ABUND.

C

FCC

RPRES.

P

PPP

P

SECTION

|

0

1

METERS

0.5-

1.0-

CoreCatcher

LITHOLOGY

VOID

fv~Ss& s & S

S?Y::: ::£i&

DEFORMATION

11i|

LITHO.SAMPLE

110


CALCAREOUS VOLCANIC SANDSTONE.Sequence of turbidites of volcanicdetritus with minor calcareousmaterial. Semilithified to lith-ified but broken up. No complete

__i turbidite sequence. Generallylight brownish gray (2.5Y 6/2) and

2.5Y 6/2 light brown (5YR 5/6). Cross-with bedding and ripples in silt and5YR 5/6 sand-size volcanic debris. Burrowed

calcareous mud at the top of oneturbidite (125-130 cm).

Smear Slide at 1-110Texture Composition(C-A-A) Palagonite A

Clay ACalcite AZeolites CVolcanic glass CFeldspar RPyrite R

Site 311

AGE

ZONE

NANNOS

FORAMS

RADS

Hole

FOSSILCHARACTER

FOSSIL

NFR

ABUND.

0

PRES.

0

Core 4

SECTION

0

1

METERS

0.5-

1.0-

:

CoreCatcher

Cored I

LITHOLOGY

VOID

ItDEFORMATION

val

LITHO.SAMPLE

* 50

22.5-28.0 m


CALCAREOUS VOLCANIC SANDSTONE.Light olive brown (5Y 5/6) andmedium bluish gray (5B 5/1). Allpart of one turbidite. Lithified,but only broken pieces sampled.Generally fine-grained sandstoneto siltstone. Massive, clastsbecoming coarser at base (s2 mm).

visible with hand lens.

X-ray 1-150Mont 63.8% Anal 1.7%Phil 27.4% Magn 2.0%Calc 5.0% Amor 46.8%

Site 311 Hole Cored Interval :28.0-37.0

AGE

ZONE

NANNOS

FORAMS

RADS

FOSSILCHARACTER

FOSSIL

NNFR

ABUND.

1 1

1 1

PRES.

1 1

1 1

SECTION

0

1

METERS

0.5-

1.0-

CoreCatcher

LITHOLOGY

VOID

V V

DEFORMATION

LITHO.SAMPLE


VOLCANIC SANDSTONE.Several turbidites. Color is mainlydusky blue green (5BG 3/2) and

some lighter shades in the finerro~ ,., grained intervals. No complete

j ' graded bed; the lithified frag-™ . ._ ments are broken up. Coarser mater-

' ial massive, finer material lamin-ated.45 to 120 cm: Some subangular brecciafragments of basalt ( 6 mm) butdominantly angular reddish brownpalagonite ( l mm).120 to 135 cm: Graded layer, someintervals missing. Finer materialat top is laminated.135 to 150 cm: Siltsize material,finely (<l mm) laminated.

Explanatory notes in Chapter 1CΛ

H

o

LO

o CORE 311-1

= GRAPE WET-BULK DENSITY, g/cc .

© Syringe porosity, % COMPRESSIONAL SOUND VELOCITY

1 2 3DEPTH POROSITY,

HOLE 2 1 0 0 50

1 -

2-

4-

5-

7-

"WET"WATERCONTENT H

wt

25

® = PerpendicularTo Bedding

A = Parallel ToBeddingkm/sec

"I "'""I

I..,.!....I I I

CORE 311-2

= GRAPE WET-BULK DENSITY, g/cc.

0 Syringe porosity, % COMPRESSIONAL SOUND VELOCITY

1 2 3DEPTHIN

HOLE

POROSITY, %,100 50 0

(m) *rg -O-i- 3

1 -

2-

4-

5-

7-

8-

75

"WET"WATER

CONTENT H% wt

25


A = Parallel ToBedd i ngkm/sec

*rg = grain density, g/ccI . . . , • . . • . I I....!....!....!....!....! l.••.lr..•l.rf.l....l....l....l....l.

*rg = grain density, g/cc

CORE 311-3

= GRAPE WET-BULK DENSITY, g/cc.


1 2 3

POROSITY, %JOO 50 0

"WET"WATERCONTENT H% wt




CORE 311-4

= GRAPE WET-BULK DENSITY, g / c c .

© Syr inge p o r o s i t y , % COMPRESSIONAL SOUND VELOCITY

1 2 3

DEPTH POROSITY, %,100 50 0

7-

8-

"WET"WATER

CONTENT H% wt



I....I....L...I....I I1...1....1....L...I....I....I....I


H

o CORE 311-5

= GRAPE WET-BULK DENSITY, g/cc


1 2 3

DEPTH POROSITY,

HOLE

1 -

2-

4-

7-

8-

"WET"WATERCONTENT B

wt

25

© = PerpendicularTo Bedding

A = Parallel ToBedd i ngkm/sec

2 3 4 5

η r~

i I....I....I...,I


I . . . . i . . . . I l • i • • i • • • • l •

SITE 311

— O c m —F

—25

—50

—75

— 100

125

1—150311-1-1 311-1-2 311-1-3 311-1-4 311-1-5 311-1-6

307

SITE 311

Ocm

1-25

1—50

h- 75

I—100

125

L—150311-2-1 311-2-2 311-2-3 311-2-4 311-2-5 311-2-6

308

SITE 311

Ocm

—25

-50

75

— 100

125

150311-3-1 311-4-1 311-5-1

309

Documents

10. SITE 311: HAWAIIAN MAGNETIC LINEATIONS