Debrisflowsand

slumps

Brownishgray toblueish

graysilty clay

Lightgreenish

graychalkwith

light–darkcycles

Mediumto lightgray

clayey chalk

with vaguecycles

Greenishgray

clayeychalk

Gray,soft clay

Laminatedblackshale

250

300

Dep

th (

mbs

f)

Microzone

14R

15R

16R

17R

18R

19R

20R

21R

22R

23R

24R

25R

26R

27R

28R

29R

30R

31R

32R

33R

34R

35R

36R

37R

38R

39R

350

400

450

500

550

(Zones areHole 1261A)

early

Eoc

ene

7R

8R

9R

10R

11R

12R

13R

M14

M13b

P14

P13

P12

P11

P11/P9

P7

NP9b

NP9a

Nodata

P5

P4

P3b

P2P3

KS31

KS24

KS23

KS22

KS21-KS20

Rar

e or

poo

lry

pres

erve

d th

roug

hout

KS29

Notzoned

Rar

e ra

diol

aria

ns o

r ba

rren

Dril

led

mid

dle

Eoc

ene

Pal

eoce

neTu

roni

ann

Maa

stric

h./

Cam

pani

an

1R

2R

3R

PL2

late

Mio

cene

(m

ainl

y M

essi

nian

sta

ge)

Sant.

Con.

NN13-NN15

NN11

NN11

witholder

blocksof

NN6- NN9

NP17 RP

14-15

Non-agediag-nostic

RP12-RP15

RP11-RP14

NP16

NP15

NP14/NP15

NP13

NP3-NP2

CC26

CC12

CC11

CC13

CC14

CC23

CC25

40R

41R

600

46R

47R

45R

4R

5R

6R

7R

8R

9R

10R

11R

44R

42R

43R

IB

Nannofossilclay

IC

Debrisflow

(Nannofossilclay with

exotic chalk andother blocks)

II

Calcareouschalk

III

Clayeycalcareous

chalk

A

B

IV

Calcareousclaystone

withorganicmatter;

nannofossilchalkwith

middlePlio.

Cor

e

Rec

over

yC

ore

Rec

over

y

Lithologicunit

Schematicvisual

appearance Age F N R

Hole1261A

Hole1261B

Ove

rprin

ted

Ove

r-pr

inte

dW

eak

Intensity (A/m)Magnetic susceptibility

(instrument units)

10-5 10-4 10-3 0 4020

Inclination

0° 60° 10-2

Shipboard pass-through magnetometer and susceptibility measurements

ODP Proceedings, Initial Reports, Volume 207

Chapter 8, Figure F9. Shipboard paleomagnetic data and initial interpretations of inclination clusters in the Cretaceous–Miocene from Holes 1261A and 1261B. Visual color variations in the sediment succession generally correspond to changes in magnetic properties and are displayed as an exaggerated schematic column to the right of the shipboard lithostratigraphic units. The paleomagnetic data from the holes have been compared using the composite depth offsets, which rarely exceeded a relative displacement of 4 m at this site. Magnetic inclinations (blue points = Hole 1261A and Upper Cretaceous red = Hole 1261B) are from intact blocks (excluding measurements within 5 cm of the end of each blocks) after 15-mT demagnetization. The inclination data exclude measurements near the background noise limit of the cryogenic magnetometer (~3 × 10–5 A/m); therefore, measurements with intensities <5 × 10–5 A/m are not considered reliable. In addition, the upper 20 cm of each core, which commonly displays spurious high-intensity magnetization or downhole contamination, and the upper 5 cm of each section, which is influenced by magnetization carried by the blue end cap, are excluded. The displayed inclinations are either 3-point running means (solid circles), 2-point means (open circles), or single-level data (open triangles) (from the central portion of blocks between 10 and 15 cm long, or from isolated levels within a larger block in which the adjacent measurements were <5 × 10–5 A/m). The magnetic intensity column includes NRM (small orange dots = 21-point running mean) and after the 15-mT demagnetization (small black dots, where large blue dots are 101-point log-mean average) for Hole 1261A. Magnetic susceptibility data for Hole 1261A obtained using a magnetic susceptibility core logger (MSCL) are shown by green dots in the rightmost column. Shipboard assignment of polarity zones was based on clusters of magnetic inclinations from intact blocks (to right of polarity zone column), as delimited by the thin lines. Zones of positive inclinations (originally considered to be normal polarity zones) = black or medium gray, if reliability is less certain; negative or mixed inclinations (originally considered to be reversed polarity zones) = white or light gray, if reliability is less certain. Uncertain inclination characteristics or gaps in data coverage = cross hatched. The shipboard interpretations of polarity zones were not always supported by analyses of magnetic characteristics during progressive thermal demagnetization of minicores (Fig. F10, p.52). F = foraminifers, N = nannofossils, R = radiolarians.

Initial polarityinterpretationsfrom inclination

model -60°

KS19

Bar

ren

Bar

ren

late

Cen

oman

ia

?VQuartz

sandstone

CC10

650

48R

49R

50R

51R

669.5 mbsf

674.1 mbsf

12R

13R

14R

15R

16R

organicmatter

ODP Proceedings, Initial Reports, Volume 20

Chapter 8, Figure F9. Shipboard paleomagnetic he Cretaceous–Miocene from Holes 1261A and 1261B. Visual color variations in the sed gnetic properties and are displayed as an exaggerated schematic column to the right of ic data from the holes have been compared using the composite depth offsets, which e. Magnetic inclinations (blue points = Hole 1261A and Upper Cretaceous red = H ts within 5 cm of the end of each blocks) after 15-mT demagnetization. The inclinati e limit of the cryogenic magnetometer (~3 × 10–5 A/m); therefore, measurem eliable. In addition, the upper 20 cm of each core, which commonly displays spuriou ion, and the upper 5 cm of each section, which is influenced by magnetization carri nations are either 3-point running means (solid circles), 2-point means (open circles), tion of blocks between 10 and 15 cm long, or from isolated levels within a larger bloc m). The magnetic intensity column includes NRM (small orange dots = 21-point runnin ck dots, where large blue dots are 101-point log-mean average) for Hole 1261A. Magn agnetic susceptibility core logger (MSCL) are shown by green dots in the rightmost c d on clusters of magnetic inclinations from intact blocks (to right of polarity sitive inclinations (originally considered to be normal polarity zones) = black or d inclinations (originally considered to be reversed polarity zones) = white or ion characteristics or gaps in data coverage = cross hatched. The shipboard interpreta lyses of magnetic characteristics during progressive thermal demagnetization of min , R = radiolarians.

7

data and initial interpretations of inclination clusters in timent succession generally correspond to changes in ma the shipboard lithostratigraphic units. The paleomagnet rarely exceeded a relative displacement of 4 m at this sitole 1261B) are from intact blocks (excluding measuremenon data exclude measurements near the background nois

ents with intensities <5 × 10–5 A/m are not considered rs high-intensity magnetization or downhole contaminated by the blue end cap, are excluded. The displayed inclior single-level data (open triangles) (from the central pork in which the adjacent measurements were <5 × 10–5 A/g mean) and after the 15-mT demagnetization (small blaetic susceptibility data for Hole 1261A obtained using a molumn. Shipboard assignment of polarity zones was base zone column), as delimited by the thin lines. Zones of pomedium gray, if reliability is less certain; negative or mixe light gray, if reliability is less certain. Uncertain inclinat

tions of polarity zones were not always supported by anaicores (Fig. F10, p.52). F = foraminifers, N = nannofossils

Inclination

0° 60°

board pass-through ma

tynsion

-60°

Debrisflowsand

slumps

Brownishgray toblueish

graysilty clay

Gray,soft clay

250

300

Microzone

14R

15R

16R

17R

18R

19R

20R

350

(Zones areHole 1261A)

7R

8R

9R

10R

11R

12R

13R

M14

M13b

Rar

e ra

diol

aria

ns o

r ba

rren

Dril

led PL2

late

Mio

cene

(m

ainl

y M

essi

nian

sta

ge)

NN13-NN15

NN11

NN11

witholder

blocksof

NN6- NN9

IB

Nannofossilclay

IC

Debrisflow

(Nannofossilclay with

exotic chalk andother blocks)

middlePlio.

Cor

e

Rec

over

yC

ore

Rec

over

y

Lithologicunit

Schematicvisual

appearance Age F N R

Hole1261A

Hole1261B

Ove

rprin

ted

Ship

Initial polariinterpretatiofrom inclinat

model

Intensity (A/m)Magnetic susceptibility

(instrument units)

10-5 10-4 10-3 0 402010-2

agnetometer and susceptibility measurements

20R

Lightgreenish

graychalkwith

light–darkcycles

Mediumto lightgray

clayey chalk

with vaguecycles

Greenishgray

clayeychalk

Dep

th (

mbs

f)

21R

22R

23R

24R

25R

26R

27R

28R

29R

30R

31R

32R

33R

34R

35R

36R

37R

38R

39R

400

450

500

550

early

Eoc

ene

P14

P13

P12

P11

P11/P9

P7

NP9b

NP9a

Nodata

P5

P4

P3b

P2P3

KS31

KS24

Rar

e or

poo

lry

pres

erve

d th

roug

hout

KS29

Notzoned

mid

dle

Eoc

ene

Pal

eoce

neM

aast

rich.

/C

ampa

nian

1R

2R

3R

Sant.

NP17 RP

14-15

Non-agediag-nostic

RP12-RP15

RP11-RP14

NP16

NP15

NP14/NP15

NP13

NP3-NP2

CC26

CC14

CC23

CC25

40R

41R

4R

5R

6R

II

Calcareouschalk

III

Clayeycalcareous

chalk

A

B

IVO

ver-

prin

ted

Wea

k

Laminatedblackshale

KS23

KS22

KS21-KS20

KS19

Bar

ren

Bar

ren

Turo

nian

late

Cen

oman

ian

Con.

?

CC12

CC11

CC10

CC13

VQuartz

sandstone

600

650

46R

47R

48R

49R

50R

51R

669.5 mbsf

45R

6R

7R

8R

9R

674.1 mbsf

10R

11R

12R

13R

14R

15R

16R

44R

42R

43RCalcareousclaystone

withorganicmatter;

nannofossilchalkwith

organicmatter