9. SITE 190
The Shipboard Scientific Party1

SITE DATA

Date Occupied: 22-24 Aug 71.
Position:
55°33.55'N
171°38.42'E.
Water Depth: 3875 meters.
Penetration: 627 meters.
Number of Holes: One.
Number of Cores: 16.
Total Core Recovered: 85 meters.
Acoustic Basement:
Depth: 1.15 seconds
Nature: Unknown
Velocity: Unknown.
Age of Oldest Sediment: Lower-middle Miocene.
Basement: Not reached.
SUMMARY

Site 190 is located in the southwestern Aleutian Basinjust east of the southern terminus of the main or northernpart of Shirshov Ridge, Bering Sea. The 627-meter thicksediment and sedimentary rock sequence drilled and coredconsists of a Holocene through upper Miocene (0-615m)
silty clay with variable amounts of diatoms, and diatomooze with variable amounts of silt and clay overlying an
upper to middle (?) Miocene (615-? m) section of mudstone, limestone, and clay. Discrete layers of vitric volcanic
ash and thin layers of volcanically derived (?) silt occur
throughout the upper Miocene and younger section (0-615m).
Although Site 190 is located over part of the abyssal
floor of the Aleutian Basin, which previous geologic studies
and seismic reflection profiles (Ludwig et al., 1971a;
1971b) imply is underlain by a thick (as much as 1000 m)
sequence of turbidite beds of late Cenozoic age, the bulk of
the cored deposits are not visibly size-graded sand or silt,

1David W. Scholl, U.S. Geological Survey, Menlo Park, California; Joe S. Creager, University of Washington, Seattle, Washington; Robert E. Boyce, Scripps Institution of Oceanography, La
Jolla, California; Ronald J. Echols, University of Washington,
Seattle, Washington; Timothy J. Fullam, Standard Oil Company ofCalifornia, La Habra, California; John A. Grow, Massachusetts
Institute of Technology, Cambridge, Massachusetts; Itaru Koizumi,
Osaka University, Osaka, Japan; Homa J. Lee, Naval Civil Engineering Laboratory, Port Hueneme, California; Hsin Yi Ling, Universityof Washington, Seattle, Washington; Richard J. Stewart, Universityof Washington, Seattle, Washington; Peter R. Supko, Scripps
Institution of Oceanography, La Jolla, California; Thomas R.
Worsley, University of Washington, Seattle, Washington.

but rather are silty or clayey diatomaceous layers. However,grain size analyses shows that many of these layers are, infact, graded units. It can be conjectured that the leveling of
the abyssal plain in the vicinity of Site 190 resulted fromthe deposition of only distal turbidites together with acontinual rain of siliceous microorganisms. However, thefact that the site is located over a slight structural dome,
across which the acoustically definable turbidite sequencethins, may have, in part, contributed to the general paucity
of coarser graded sand and silt layers.
Within the acoustically measured turbidite section (250m), only the upper 175 meters contain coarse size-graded
beds. Presumably this section, which corresponds to theentire Pleistocene, signifies glaciation and glacially lowered
sea levels. However, displaced freshwater and littoral
diatoms occur to a depth of 200 meters in upper Pliocene
diatomaceous and silty beds, and acoustically the turbiditebearing sequence extends at least 50 meters deeper (seeScholl and Creager, this volume). The silty diatom ooze anddiatomaceous silty clay below 375 meters is wormburrowed and semi-indurated and largely of late late
Miocene age. Except for the occurrence of size-graded
terrigenous turbidites, the entire diatomaceous section(0-615 m) is similar in age and lithology to Unit A
recognized at other (except Site 188) Bering Sea sites. The
upper or middle (?) Miocene claystone and limestone
recovered below this depth are temporally and lithologically equivalent to Unit B encountered at these sites.
BACKGROUND AND OBJECTIVES
Description

The Aleutian Basin of the Bering Sea, a classical marginal
oceanic basin, is floored by a vast abyssal plain occupying
nearly all of the deep-water areas north of the Aleutian
Ridge. Site 190 is located in about 3800 meters of water
near the southwestern corner of the basin. The location is
also near the southern terminus of the north-trending
Shirshov Ridge (Figure 1).
Seismic reflection profiles reveal that about 1000 metersof stratified deposits underlie the basin floor at Site 190;
elsewhere the thickness is considerably greater. At Site 190
an acoustic basement occurs at 1.15 sec below bottom. The
overlying deposits appear to include highly reflective silty
and possibly sandy turbidite beds forming the upper 250 to
300 meters; an underlying sequence of poorly reflecting
pelagic beds about 400 meters thick, a sharp reflector at thebase of this sequence, and about 300 to 400 meters of
weakly reflecting strata resting on the acoustic basement(Figures 2 and 3) Site 190 is located over a 300- to
400-meter high basement ridge that causes a slight shoalingof the overlying sea floor and a thinning of underlying
units, including the turbidite sequence.

371

SITE 190
Objectives

56°

Interest in the textural and sedimentary structures of theturbidites flooding the abyssal depths of the Aleutian Basinand in its general history of sedimentation prompted
drilling at Site 190. The age of the base of the turbidite
sequence was also to be determined — this in order tobracket the timing of the first glacially(?) lowered sea leveland possibly the initial carving of the enormous submarine
canyons that cut into the Bering Sea continental slope andouter shelf. Also of interest is the age and composition of
the pelagic unit sandwiched between the turbidite sequenceand the acoustic basement; it is especially important toknow if turbidite beds are interbedded in this sequence. A
prominent subbottom reflector at about 0.78 sec, thought
to be a silty layer, was to be reached and sampled.
OPERATIONS
Pre- and Post-drilling Survey

Figure 1. Base map showing the location of Site 190.

Site 190 is located just east of Shirshov Ridge in the
Aleutian Basin, Bering Sea, along the track of the reference
profile obtained by D.W. Scholl on 25 Aug 70 (Figure 2).
The site was approached with a ship's heading of 033°T
wjiich was approximately the reciprocal of the heading usedin obtaining the reference profile. The air-gun profile
obtained during the approach (Figure 3) so closely approximated the reference profile that the beacon was dropped on

Figure 2. Site 190 reference seismic reflection profile, obtained by D. W. Scholl, 25 Aug 70.

372

SITE 190

cr>

Figure 3. Glomar Challenger seismic reflection profile obtained on approach to Site 190.
the fly at 1930 hrs on 22 Aug 71. The finally accepted
position is: 55°33.55'N; 171°38.42'E. No post-drilling
survey was deemed necessary. A map showing the approachand departure tracks plus the site location is shown in
Figure 4.
Drilling Program

Site 190 was occupied from 1930 hrs 22 Aug 71 (beaconaway) until 1700 hrs 24 Aug 71 with alternate coring andwashing from the sea floor to a subbottom depth of 627
meters. Cores from depths between 609 and 627 meters
contained limestone and mudstone which were extremely
difficult to core with the core extender and bit assembly
being used. These sedimentary rocks correlate well with thelast prominent reflector above that considered acoustic
basement. Considering the time left for this leg and the
difficulty of further drilling or coring, the hole wasterminated.

373

SITE 190
171 25'E

TABLE 1
Core Summary - Site 190

SITE 190β

17181/24 AUG 71

55'33.6'N x 171 38.4'E

1920L/22 AUG 71
C/S 0 Kts

Core

Below Bottom
(m)

Cored

(m)

(m)

(%)

1
2
3
4
5

0-6
6-15
15-24
24-33
33-43

6
9
9
9
10

6.0
3.0
4.9
5.8
9.2

100.0
33.3
54.4
64.4
92.0

6
Wash
7
8
Wash

43-52

9

7.5

83.3

75-84
84-93

9
9

7.5
6.3

83.3
70.0

112-121

9

4.5

50.0

150-159

9

3.9

43.3

197-206

9

6.3

70.0

225-234

9

5.5

61.1

328-337

9

4.5

50.0

421-430

9

9.2

102.2

609-618618-627

9
9

0.9
CC

10.0
0.0

142

85.0

59.9

55°3O'N

9
Wash
10
Wash
11

Figure 4. Glomar Challenger
tracks, Site 190.

approach anddeparture

Using Matthews Tables, the sonic depth of 2060 fms wascorrected to 3848 meters, giving a water depth of 3854
meters and a drill-floor depth of 3864 meters. This
compares with 3885 meters below drill floor established on
the basis of the first core collected which contained
sediment with a good oxidized surface. The 3885 meters
below drill floor or 3875 meters below sea level is theaccepted depth at this site.
No difficulties were encountered in drilling this holethrough 609 meters of fine-grained sediment. Drilling rates
were approximately 100 meters per hour until the limestone and mudstone was encountered. The core extenderand bit assembly being used was not the proper combination for coring or recovery of this hard material. This wasunderstood before the hole was started. A coring summaryis given in Table 1.
LITHOSTRATIGRAPHY

The 627-meter Holocene to middle Miocene section at
Site 190 consists primarily of greenish gray silty clay withvariable amounts of diatoms, and olive gray diatom ooze
with variable amounts of silt and clay. The sediments havebeen divided into two major units based on diatom content
and preservation (Table 2). In the upper unit, A (0 to 615m), diatoms are well preserved and abundant, constituting
as much as 95 per cent of the volume of some layers.
Sediments in the lower part of Unit A are semi-indurated
and burrowed and probably represent a transition to
Unit B, even though the diatom content remains high.
Unit B (615 to 627 m) consists of mudstone and clay
containing only scattered and severely corroded diatom
fragments.
Discrete beds of vitric volcanic ash and thin layers of silt
occur throughout Unit A. In the Pleistocene portion (Cores
1-10, 0-175 m) of Unit A, the size-graded silt layers are
thicker (up to 15 cm) and more numerous than below 175
meters, and are associated with several thick (up to 25 cm)
layers of size-graded sand and silt. The size-graded sandsand silts are presumably turbidites and, although they do
not form the major part of the Site 190 sediment, they

374

Recovered

Cored Interval

DEPART

Wash
12
Wash
13
Wash
14
Wash
15
16

TABLE 2

Unit

Cores

Depth Below
Sea Floor
(m)

1-15

Lithology

Age

0-615

Diatom silty clay:
diatom ooze

Upper Pleistocene
to upper Miocene

1-10

0-175

Diatom-bearing
to rich silty clay
with several sizegraded sands andsilts

Upper to lower
Pleistocene

11-13

175-375

Diatom ooze

Pliocene to upper
Miocene14-15

375-615

Diatom ooze anddiatom silty clay
semiindurated,burrowed

Upper Miocene

16615-627

Mudstone plus
clay and limestone, containing
solution-corroded
diatoms

Upper Miocene
Middle Miocene(limestone pebble)

could be responsible for the leveling of the late Cenozoic
fill over this area of the Aleutian Basin.
Unit A - 0 to 615 Meters
Most of the sediments recovered at Site 190 are
interbedded mixtures of diatoms, silt, and clay. Typically,SITE 190the sediments are olive gray to dark greenish gray diatombearing to diatomaceous silty clay, and silt- and claybearing diatom ooze. Color variations are associated withslight compositional changes, and, in general, the grayer
colored sediments are richer in silt and clay. For the mostpart, the pelagic and terrigenous components are about
equal; however, the number and thickness of diatom ooze
layers and the diatom content of the silty clays generally
increase toward the bottom of the unit.
A well-developed, oxidized surface layer of diatom ooze,
20 to 25 cm thick, occurs at the sediment-water interface.
The colors of the layer range from dark yellowish brown toolive to grayish olive.
Numerous vitric volcanic ash beds occur throughout
Unit A. They are typically 5 to 10 cm thick, but attain amaximum thickness of about 50 cm (Core 8, 85 m below
bottom). Colors range from very light gray for nearly pure
light-colored glass ashes to brownish gray for ashes containing up to 25% silt and/or clay. Also occurring are a few thinstreaks of dark-colored crystal ash containing large amountsof feldspar (25%), lithic fragments, altered glass, andunidentified material (40%), in addition to light- anddark-colored glass shards.
The upper part of Unit A (0-175 m) is distinguished by
the presence of at least four visibly size-graded sand and silt
layers, all about 25 cm thick. (Grading in other sands andsilts has been revealed by detailed size analyses. Colors of
the graded layers are dusky yellowish brown to olive
black.
The lower part of Unit A (375-615 m) is semi-indurated
and burrowed. Burrows generally are parallel to bedding,which is horizontal. Numerous thin laminae of olive black
volcanic silt containing pyritized diatoms occur in thedominant diatomaceous silty clay and clayey diatom ooze.
The core catcher sample from Core 15 at the base of Unit A
contains a piece of diatom-bearing limestone which
probably was responsible for a drilling break at 609 meters
below bottom.
Unit B - 615 to 627 Meters
A single core catcher sample constitutes Unit B. Sediments recovered include two pieces of mudstone, a small
piece of limestone with well-preserved middle Miocene
diatoms and silicoflagellates, and olive gray clay containing
scattered solution-corroded diatoms.
PHYSICAL PROPERTIES

Bulk density, water content, natural gamma radiation,
acoustic velocity, thermal conductivity, vane shear strength,
and residual negative pore water pressure were measured on
the samples obtained. The bulk density was measured with
the GRAPE system and calculated from shore laboratorywater content testing. Four 6-cm long unsplit sections wereobtained for consolidation testing on shore. The GRAPE
densities are shown on the core summary sheets. The mean
GRAPE densities for the sections tested are shown on thesite summary sheet along with the acoustic velocities.
Site 190 is important from a physical-engineering properties point of view because sampling was nearly continuous
over the critical first 100 meters, the samples were of

relatively good quality, and the sediment was relatively
homogeneous. Because of these favorable conditions, thenumber of consolidation test samples taken at this site wasgreater than at any other site of this leg. An analysis of theresults of these consolidation tests is given in a separate
chapter by Lee (this volume).
Bulk Density

The GRAPE density was measured on all sections
through Core 14. However, it appears that the results on
Core 14 are inaccurate, probably because of inadequate
filling of the core liner. Therefore, only results throughCore 13 are presented.
As may be seen from the core summary sheets, thesmall-scale variations in the GRAPE record correlate wellwith small-scale variations in the lithology. Diatom ooze
layers register as low-density zones; ash and sand layers
register as high-density zones; diatom clay sections represent medium-density zones. Taking the site as a whole (sitesummary sheet) the GRAPE density data are quite scattered over the first 50 meters, reflecting the presence ofnumerous ash and sand layers. The scatter decreases overthe next 50 meters, and the general trend of the data is oneof gradually increasing density produced by compaction of
the diatomaceous clay. From 100 to 200 meters the density
decreases somewhat as the diatom content increases. Below
200 meters the density again begins to increase.
There are no sharp breaks in the data. Rather, thedensity varies gradually over the depth range sampled andreflects gradual changes in lithology.
Acoustic Velocity
The acoustic velocity does not deviate from the range
1.5 to 1.6 km/sec for the entire depth span tested (0 to 425m). There are, however, important variations in the velocity
distribution with depth. Over the first 100 meters thevelocity increases from about 1.5 to 1.55 km/sec. It
decreases to 1.5 km/sec at 120 meters and then begins togradually increase again, finally reaching a value of 1.6
km/sec at 425 meters. This reflects the lithologic changes
noted in the bulk density section.
Summary

The physical properties indicate a relatively uniform
sediment extending to a depth of 425 meters. Both density
and acoustic velocity increase to a depth of 100 meters,
decrease slightly to 200 meters, and then increase again to
425 meters. The variations are small, but apparently reflect
a slight change in sediment type over the range 100 to 20ometers.
PALEONTOLOGY

Correlation with previous sites by means of diatoms andsilicoflagellates is good, but Radiolaria decrease in diversity
below Core 4 (middle Pleistocene) to a few nondiagnostic,
long-ranging species. Core 16 is devoid of fossils with the
exception of a limestone pebble containing middle Miocene
silicoflagellates and diatoms. Displaced freshwater diatoms
were found down through Core 10.
Planktonic foraminifera occur in the Pleistocene section,
but are virtually absent below, as at previous sites. Cores

375

SITE 190

13, 14, and 16 contain an arenaceous fauna. Displaced shelf
species are mixed with the typical deep-sea benthic fauna inCore 5.
All sediments are devoid of calcareous nannofossils
except nondiagnostic species in Cores 1 and 3 (Pleistocene).
The occurrence of planktonic foraminifera in the other
Pleistocene cores without nannofossils may be a result of
selective exclusion from very cold (less than 1°C) surface
water (Mclntyre et al., 1972).
Foraminifera

In the Quaternary section, planktonic and calcareous
benthic foraminifera fluctuate in abundance from sample tosample. All calcareous tests are absent in some Quaternary
samples, which are either barren or have a sparse arenaceous
fauna. Only a sparse arenaceous fauna occurs in the surface
sediment (the oxidized layer, Core 1).
Late Pliocene samples (from Cores 11 and 12) are barrenof foraminifera. Early Pliocene to late Miocene corescontain Martinottiella communis (Cores 13, 14, and 16),
Eggerella sp. (Core 15), and Cyclammina sp. (Core 16).
Preservation of the arenaceous test of these species is good
except in Core 16 where the tests of Cyclammina are
infilled with an undetermined material and badly deformedby compression. No other species were found. These species
also occur in the indurated sediments of Unit B of someprevious Bering Sea sites.
Radiolaria and Silicoflagellates

Sediments of Site 190 yield rather good radiolarian andsilicoflagellate assemblages. Most of the radiolarian taxa
reported in the study of Bering Sea sediments (Ling et al.,1971) were encountered in the uppermost two samples ofthis site (Table 9, Chapter 28). Both Eucyrtidium(?)
tumidulum and Stylacontarium acquilonium were found inCore 3, the latter species, however, was recovered also inCores 4 and 6 (questionably in Core 13). Starting fromCore 4 downward, species diversity of Radiolaria decreases
gradually and consists of long-range forms only. The clayey
part of Core 16, the lowest of this site, is completely barrenof Radiolaria.
The microfloral succession of silicoflagellates recoveredfrom this site (Table 9, Chapter 27) agrees well with thosepresented from previous sites.
Although the clayey sediments of Core 16 were barrenof silicoflagellates, a limestone pebble caught in the corecatcher contains several specimens of Cannopilus sphaericus
in addition to other Miocene forms. This finding not only
marks the first occurrence for this species during this leg,but also constitutes the first record of the species from sucha high-latitude area. Occurrence of this form in the sectionof Newport Beach, California, and the experimental Mohole
sediments at Guadalupe site, is limited to the Luisian Stage.

376

Diatoms
Diatom valves observed from this site are abundant andwell preserved and the stratigraphic sequence of diatoms
through Core 16 at Site 190 is shown in Table 8, Chapter
30.
Although the clayey sediments of Core 16 in the lowest
part of the sequence is barren of diatoms, a limestone
pebble included in the sediments contains many wellpreserved middle Miocene index species for the northern
Circum-Pacific region; they are Actinocyclus ingens, A.
tsugaruensis, Synedra jouseana, Denticula lauta, andKieselavia carina, etc.
CORRELATION BETWEEN REFLECTION PROFILEAND STRATIGRAPHIC COLUMN

The reflection profile collected by D. W. Scholl, 1970,
which was used to select Site 190, is shown in Figure 5
along with the stratigraphic column and physical properties.
A sonobuoy reflection profile (wide-angle) taken by the
Glomar Challenger while on station is shown in Figure 6.
The upper 0.40 sec on both records show well-developed
internal stratification. This is presumably caused by interbedded diatom ooze and ash layers and rare silt andsize-graded turbidite sequences. A zone of more transparent
sediments occurs between 0.40 and 0.75 sec, particularlyon the sonobuoy profile (Figure 6), and correlates withsilty diatom ooze and diatomaceous silty clay lacking silty
turbidite layers.
Between 0.75 and 0.80 sec a strong reflector (particularly in Figure 6) can be seen which corresponds to the topof Unit B, the mudstone. Acoustic basement was recorded
somewhere between 1.1 and 1.3 sec; its lithology is
unknown.
Interval velocities within Unit A, based on the shipboard
laboratory measurements, are near 1.6 km/sec; the traveltime solution (i.e., to the top of Unit B) is also between
1.55 and 1.65 km/sec (615 m by either 0.75 or 0.80 sec).
REFERENCES

Ling, H.Y., Stadum, C. and Welch, M., 1971. PolycystineRadiolaria from the Bering Sea surface sediments. Proc.
2nd Intern. Plankt. Conf. Rome. 2, 705.
Ludwig, W.J., Marauchi, J., Den, N., Ewing, M., Hotta, H.,
Houtz, R.E., Yoshii, T., Asanuma, T., Hagiwara, K.,
Sato, T. and Ando, S., 1971a. Structure of Bowers
Ridge, Bering Sea. J. Geophys. Res. 76 (26), 6250.
Ludwig, W.J., Houtz, R.E. and Ewing, M., 1971b. Sediment
distribution in the Bering Sea: Bowers Ridge, Shirshov
Ridge, and enclosed basins. J. Geophys. Res. 76 (26),6367.
Mclntyre, A., Ruddiman, W.F. and Jantzen, R., 1972.
Southward penetrations of the North Atlantic Polar
Front: faunal and floral evidence of large-scale surface
water mass movements over the last 225,000 years.
Deep-Sea Res. 19, 61.

SITE 190

E

^

CD

S>;

DENSITY

Q•~

P
[

IU
9

I0
σ

- o •
CM

WITH
GRADED
SANDS
AND
SILT
-

c\l^-U3

'CD

. . .

•t

,_! ,

i_

LU
-J

1 1• -

AND

SIL

-

5 DIATOM
d
OOZE
" 1—
>-

13 •

•

t

*
•

i .
:
>
•

•

^

LU
•z.
LU

o

LIO

o

- ro
o -

j , . .M . CM

α.

12

A

,— C M i — N

•
•

oo

1

,

VELOCITY
OlOO«3•

a.

LU

rocEi

o
- 1o -

LU

Q.
3E.

f2
o

• o

^i-

_ Q

-

14

SEMIINDURATED

•

V

LU

o

- LO
o -

LU
O

-

•

1

o

Σ.

15
16

ACOUSTIC BASEMENT (1.3 SEC)

\

- 1

B

MUDSTONEHOLETERMINATED
AT 630 M

M.MIO

•

i

i

i

i

1

1

1

1

Figure 5. Correlation of reference seismic reflection profile, physical properties, and lithologic column, Site 190.

377

SITE 190

SonobuoySite 190
80/40 Hz
4 sec.

2-way
time,
sec

rθ

-.5

-6

-1.0

Basement ?
Multiple ?

^Figure 6. Sonobuoy profile, Site 190.

378

-I

SITE 190

SITE 190

DENSITY(gm/cc)Mean GRAPE Density, +Shore Laboratory Density, x
Water Displacement Density,

DEPTH
(m)

LITHOLOGIC DESCRIPTION

.0

2.0

DENSITY(gm/cc)Mean GRAPE Density, +Shore Laboratory Density, x
Water Displacement Density,

COMPRESSIONALWAVE
VELOCITY(km/sec)
j

2.0

(m)

LITHOLOGIC DESCRIPTIONA A A A A A

A A A A A A

UNIT A(see sheet 1)

A A A A A A~

UNIT A
DIATOMACEOUS
SILTY CLAY,
greenish gray,grading locallyto DIATOM OOZE,
olive gray.
Numerous ash layers
in upper part ofsection.
Silt layers are more
numerous and thicker
above 175 m than below.
Most are size-graded.

Below α.375 m,
Unit A is semiindurated andburrowed.

A A A A A A

/

z
O•>

-J

A AA A A.0

2.0

COMPRESSIONALWAVE
VELOCITY(km/sec)j

2.0

SITE 190

ooo

DENSITY(gm/cc)Mean GRAPE Density, +Shore Laboratory Density, x
Water Displacement Density,

LITHOLOGIC DESCRIPTIONUNIT A(see sheet 1)

UNIT B
MUDSTONE, black

.0

2.0

COMPRESSIONALWAVE
VELOCITY(km/sec)
2.0

SITE 190
S i t e 190

HoleCore 1

Cored I n t e r v a l : 0-6

FOSSILCHARACTER

LITHOLOGY

LITHOLOGIC DESCRIPTION

VOID
PF
BF
D
R
S
PF
BF

F
A
R
F
C

-43
-52

0.5 —

1.0-

2KS

•84
-105
-130

-34

-39
-85

oxidized surface layer: DIATOM OOZE (80-95% diatoms)
dark yellow brown (10YR 3/4) - olive (5Y 4/3) - grayish
olive (10Y 4/2)
SAND layers, olive black (5Y 2/1), very fine grained
Slide 1-105
Slide 1-84
40% feldspar
40% feldspar
15% pyroxene
25% pyroxene
15% lithics
20% lithics
10% opaques
5% amphibole
5% amphibole
10% quartz
10% quartz

SILTY SAND, very fine grained
60% feldspar, 5% pyroxene, 5% lithics, 5% opaques,
20% quartz
Basic lithology-125
DIATOM RICH to DIATOMACEOUS SILTY CLAY
olive gray (5Y 3/2)
VOID
scattered pods and thin layers of
DIATOM OOZE and SAND
SAND

-75

Core
Catcher
Explanatory notes in Chapter 1

382

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3
11 i • i I i i • ' i > 'POROSITY,%
100
0

SECTIONCM-0' i « ' " 11Grain
Density
2 o

M
O-i

1-

-25

2-

-50

3-

4-75

-100

-125
8-

-150

190-1-1 190-1-2 190-1-3 190-1-4 190-1-5

383

SITE 190
Site 190

Hole

Core 2

Cored Interval:6-15

FOSSILCHARACTER
LITHOLOGY

0.5-

LITHOLOGIC DESCRIPTION

-45
-81

Basic lithology
DIATOM BEARING SILTY CLAY andDIATOM RICH SANDY CLAYEY SILT
olive gray (5Y 3/2)

1.0-

-15

-96

Core
CatcherR

M

Explanatory notes in Chapter 1

384with scattered bands and pods of
SAND BEARING SILTY CLAY and1-4 cm thick layers of
SANDY DIATOMACEOUS SILT light olive gray (5Y 5/2)

VITRIC ASH very light gray (N8)VITRIC ASH wery light gray (N8)

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3

CM

1 i i ' i ' ' '

rθ

Grain
Density

POROSITY,100
I 1 i I

32 o
3
<•>
1 - E
-3 3 σ>SECTION

M
Q_-

1-

r-25

2-

-50

4H
-75

5-

6-

-100

7-

-125
8-

-150

190-2-1 190-2-2

385

SITE 190
Site 190

Hole

Core 3

Cored I n t e r v a l : 1 5 - 2 4

FOSSILCHARACTER

LITHOLOGY

0.5—

LITHOLOGIC DESCRIPTION

VOID

1.0VITRIC ASH, very light gray (N8) (layer about 2 cm thick)-45-55

2 cm VITRIC ASH, olive gray; contains 10-20% clay
VITRIC ASH, olive gray (5Y 3/2), 80-90% glass shards
10-20% clay

-105

-10
-55
-65

-23
-50

SANDY SILT (disturbed layer, about 5 cm thick)

Basic lithology
DIATOM RICH SILTY CLAY
olive gray (5Y 3/2) - dark greenish
gray (5GY 4/1)
with scattered streaks, pods, and layers of
SILT RICH CLAYEY DIATOM OOZE, grayish olive(10Y 4/2), compact SILT BEARING CLAY, darkgreenish gray (5GY 4/1 - 2/1), and bands andpods of SILT and SANDY SILT, olive black (5Y 3/1)

Slide 2-55 (diatom ooze layer)
50% diatoms
20% silt
30% clayCore
Catcher-vr
Slide 2-105 (basic lith.)
10% diatoms
30% silt
60% clay

Slide 4-23
40% clay
30% feldspar
10% pyroxene
10% glass
5% diatoms
2% opaque
Explanatory notes in Chapter 1

386

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3

SECTIONCM

Grain
Density
I2 o

POROSITY,*
100
0
» I

π

l3t

ro
N
ù-i

1-

-25

2-

-50

3-

4-75

5-

-100

6-

7-

-125

8-

L-150

190-3-1 190-3-2 190-3-3 190-3-4

387

SITE 190
Site 190

Hole

Core 4

Cored Interval: 24-33

FOSSILCHARACTER

LITHOLOGIC DESCRIPTION

LITHOLOGY

VOID-30
0.580A

mixture of DIATOM RICH and DIATOMACEOUS CLAYEY SILT
olive gray (5Y 3/1 - 4/1)
10-30% diatoms
30-60% silt
20-40% clay

-140
-33

SANDY SILT (irregular pods)

68
90

ASH
DIATOM BEARING SILT RICH CLAY
dark greenish gray (5GY 4/1)
3 layers of VITRIC ASH
pinkish gray (5YR 8/1)

ASH

composition range:
TR - 5% diatoms
10 - 20% silt
80 - 85% clay

ASH

-10

-89

SANDY SILT, olive black (5Y 2/1), gradedmixtures of DIATOM RICH SILTY CLAY
andCLAY BEARING SILTY DIATOM OOZE
olive gray (5Y 3/1 - 4/1)

.119
120
thin layers, pods of SANDY SILT, olive black (5Y 2/1)
Core
Catcher

Slide 4-119
55% diatoms
35% silt (feld.pyrox.)
10% clay

Slide 4-120
15% diatoms
25% silt
60% clay
Explanatory notes in Chapter 1

388

SITE 190

WET-BULK DENSITY, gm/cc
SECTION
CM
rθ

M
O-i

1-

•25

'

:

2-

-50
3-

4-75

5-

-100

-125

-150

190-4-1 190-4-2 190-4-3 190-4-4

389

SITE 190
Site 190

Hole
FOSSILCHARACTER

Core 5

Cored Interval:33-43

LITHOLOGY

LITHOLOGIC DESCRIPTION

0.5—

DIATOMACEOUS SILTY CLAY
dark greenish gray (5GY 4/1)
Slide 1-75
40% diatoms
30% silt
30% clay-75
1.0-

SILT RICH DIATOMACEOUS CLAY
-75
Slide 2-75
30% diatoms
20% silt
50% clay

DIATOM and SILT RICH CLAY
-75
Slide 3-75
10% diatoms
20% silt
70% clay-60

145

SILTY SAND

21
60
86

SILT RICH CLAYEY DIATOM OOZE
light olive gray (5Y 5/2)
Slide 5-86
50% diatoms
10% silt
40% clay

-30

•95
120

Core
Catcher
Explanatory notes in Chapter 1

390

DIATOM and SILT RICH CLAY
dark greenish gray (5GY 4/1)
composition range:
5 - 10% diatoms
15 - 20% silt
70 - 80% clay
pods and thin layers of SANDY SILT and SILT RICH
CLAYEY DIATOM OOZESITE 190

WET-BULK DENSITY, gm/cc
12
3|i i i •I i i i i I • ' " ' I • 'POROSITY,*SECTION
M

CM
-0

Grain
Density
M

On

l-

-25

2-

-50

3-

-75

-100

6-

-125

-150

190-5-1 19Q-5-2 190-5-3 190-5-4 190-5-5 190-5-6

391

SITE 190
Site 190

Hole

Core 6

Cored Interval: 43-52

LITHOLOGIC DESCRIPTIONInterbedded and mixed by coring:
DIATOM and SILT RICH CLAY
DIATOMACEOUS SILTY CLAY andSILT RICH CLAYEY DIATOM OOZE
dark greenish gray (5GY 4/1) toolive gray (5Y 3/2)

392

Slide 1-75
45% diatoms
10% silt
45% clay

Slide 1-128
60% diatoms
10% silt
30% clay

Slide 4-75
20% diatoms
10% silt
70% clay

Slide 4-123
40% diatoms
20% silt
40% claySITE 190
WET-BULK DENSITY, gm/cc
1

2| i i i i | i i i i I i i ' "SECTION
CM

3
I i '

i M

ro

Grain
Density

POROSITY,*-3 2 o

M

'

I

M
On

1-

-25

2-

-50

3-

4-75

-100
6-

-125

8-1

—150

i

190-6-1 190-6-2 190-6-3 190-6-4 190-6-5

393

SITE 190
S i t e 190

HoleCore 7

Cored I n t e r v a l ; 7 5 - 8 4

FOSSILCHARACTER

LITHOLOGY

LITHOLOGIC DESCRIPTION

0.5 —

44
46
54
•66

l.O

-95

DIATOM OOZE, olive gray (5Y 4/2), 95% diatoms
SILT and CLAY BEARING VITRIC ASH
olive gray (5Y 4/1) to dark yellow brown (10YR 3/2)

DIATOMACEOUS CLAYEY SILT (?)
olive gray (5Y 4/1)
75

-59

Basic lithology
DIATOM and SILT RICH CLAY to
DIATOM RICH SILTY CLAY
dark greenish gray (5GY 4/1)
composition range:
10 - 25% diatoms
10 - 30% silt
50 - 70% clay

-107
pods, streaks and thin bands of olive black(5Y 3/1) SILT and olive gray DIATOMACEOUS CLAYEY SILT
erratic shale fragment, sec. 5, 15 cm
-75

148

Core
Catcher
Explanatory notes in Chapter 1

394

GLASS and DIATOM RICH SAND, olive gray (5Y 3/2)
25% diatoms, 35% feldspar, 15% l i t h i c s , opaque etc.
15% glass, 5% pyroxene and other
CARBONATE and SILT BEARING CLAY RICH DIATOM OOZE
65% diatoms
5% s i l t
XR 2-60
Core Catcher:
10% carbonate
43% amorph.
D A G
20% clay
17% quartzN
13% plag.
R
R M
21% mica
S
F M
PF 5% chlor.
BF 2% mont.

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3
POROSITY,%
100
0

SECTION
CM

rθ

Grain
Density
M
On

-25

2-

-50
3-

4-75

6-

-100

7-125

8-

-150

190-7-1 190-7-2 190-7-3 190-7-4 190-7-5

395

SITE 190
Site 190

Hole

Core 8

Cored I n t e r v a l : 84-93

FOSSILCHARACTER

LITHOLOGIC DESCRIPTION

LITHOLOGY

0.5 —

VOID

1.0-

li = >

55% silt, 45% clay

130

CLAYEY SILT
to•25

DIATOM RICH CLAYEY SILT 10% diatoms, 50% silt,
dark greenish gray (5GY 4/1)

-70

VITRIC ASH, olive (5Y 4/3)

clay

II-

-100
145 ASH-24

SILT and CLAY BEARING DIATOM OOZE
light olive gray (5Y 5/1)
80 - 85% diatoms
5 - 10% silt
10% clay

84
100
-141

CLAY RICH SILTY DIATOM OOZE
greenish gray (5GY 4/1)
60% diatoms
30% silt
10% clay

DIATOM OOZE, light olive gray (5Y 5/1)

-46
-95

Core
Catcher

Explanatory notes in Chapter 1

396

SILT and CLAY BEARING DIATOM OOZE, grayish olive (10Y 3/2)

DIATOM BEARING SILTY CLAY
olive gray (5Y 3/2) to dk greenish gray (5GY 3/1)

pods, streaks and thin bands of:dark feldspathic silt andcompact greenish black clay
throughout the core

SITE 190

WET-BULK DENSITY, gm/cc
I
2
3
I1

i i i i i i i i i i

POROSITY,%100
0i • i i i i

SECTION
CM

11

ro

Grain
Density-3 2 o

M

M
O-i

1-100

125

9-1

1-150

190-8-1 190-8-2 190-8-3 190-8-4 190-8-5

397

SITE 190
Site 190

Hole

Core 9

Cored I n t e r v a l : 1 1 2 - 1 2 1

FOSSILCHARACTER

LITHOLOGIC DESCRIPTION

LITHOLOGY

0.5-

=9
12
15

VITRIC ASH olive gray (5Y 4/1)
70% glass shards
20% feldspar
10% other

2 cm layer-75
1.0Basic lithology:
DIATOM and SILT RICH CLAY
dark greenish gray (5GY 4/1)
10 - 25% diatoms
5 - 25% silt
65 - 75% clay
thin interbeds, pods and streaks of:1) DIATOMACEOUS CLAYEY SILT
olive gray (5Y 4/1) 30% diatoms
2) FELDSPATHIC SILT olive black (5Y 2/1)
3) SILT RICH CLAY
greenish black (5GY 3/1)
75

CoreCatcher
Explanatory notes in Chapter 1

398

DIATOM OOZE layers, olive gray (5Y 3/1)
Core Catcher
XR 2-3075% amorph.
D A G
9% quartz
N - 4% plag.
R F M
10% micaS
M
2% chlor
PF R
TR mont.
BF R

SITE 190

WET-BULK DENSITY, gm/cc
I
2
3
I1 i i • I i i ii « ' •' i

POROSITY,%
100
0

SECTION
CM

«I

ro

Grain
Density
M
0-1

-25

2-

-50
3-

4-J

-75

5-

-100

6H

7-

-125

i

) HEE
190-9-1

399

SITE 190
Site 190

Hole

Core 10

Cored Interval:150-159

LITHOLOGIC DESCRIPTION

Basic lithology (sections 1 and 2)
DIATOMACEOUS SILTY CLAY
olive gray (5Y 3/2)
Slide 1-90
30% diatoms
30% silt
4 0 % clay
SILTY DIATOM OOZE
dark grayish olive (10Y 3/2)
55% diatoms, 45% silt

SILT and CLAY BEARING DIATOM OOZE, grayish olive (10Y 4/2)
FELDSPATHIC SILT, olive black (5Y 2/1)
Slide 2-85
Slide 2-92
90% diatoms
3 - 5% diatoms
10% silt, clay
60% feldspar and
SILT, gradedqtz(?)
30% pyroxene,
other heavy
VITRIC ASH pod
5% opaques
CLAY RICH SILTY DIATOM OOZE
olive gray (5Y 3/2)
Slide 3-72
50% diatoms
30% silt
20% claystreaks pods and thin layers of:
FELDSPATHIC SILT and SAND
and compact greenish black (5GY 2/1) CLAY
Explanatory notes in Chapter 1

400

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3

SECTIONCM-0

I i i i i I i i i i I i ' ' ' I ' ' ' M

POROSITY,*
100
0

Grain
Density"32 u
1 , •E3 3 σ»

2-

-50
3-

4-75

5-

6-

-100

7-

-125
8-

-150

190-10-1 190-10-2 190-10-3

401

SITE 190
Site 190

Hole

Core 11

Cored Interval:197-206

FOSSILCHARACTER

LITHOLOGY

0.5-

LITHOLOGIC DESCRIPTION

VOID

1.0—

-75
DIATOM RICH SILTY CLAY
dark greenish gray (5GY 4/1)
Slide 2-75
Slide 3-75
20% diatoms
20% diatoms
40% silt
20% silt
40% clay
60% clay
TR carbonate
-75
o .^

gradational zone
-100

-38

SILT and CLAY BEARING DIATOM OOZE
olive gray (5Y 4/2)
Slide 4-100
85% diatoms
5% silt (feldspar)
10% clay
VITRIC ASH pods
gradational zone

130
Core
Catcher
Explanatory notes in Chapter 1

402

SILT BEARING CLAYEY DIATOM OOZE
dark gray (5Y 4/1)
Slide 5-130
60% diatoms
10% silt
30% claySITE 190
WET-BULK DENSITY, gm/cc
1
2
I' ' ' ' I
POROSITY,*
100
0

SECTION
CM

3

ro

Grain
Density
-a2 o
M
O-

1-

-25

2-

-50

3-

4-75

5-

-100

6-

7-

-125

8-

1—150

190-11-1 190-11-2 190-11-3 190-11-4 190-11-5

403

SITE 190
Site 190

Hole

Core 12

Cored Interval:225-234

LITHOLOGIC DESCRIPTION

DIATOMACEOUS SILTY CLAY
with ~5 cm layers of
SILT and CLAY BEARING DIATOM OOZE
dark gray (5Y 4/1) and dark greenish gray (5GY 4/1)
Slide 1-60
30% diatoms
30% silt
40% clay

Slide 1-64
80% diatoms
5 - 10% silt
10 - 15% clay, TR carbonate

SILT BEARING CLAYEY DIATOM OOZE
dark greenish gray (5GY 4/1)
Slide 2-75
50% diatoms
10% silt
40% clay
GLASS RICH FELDSPATHIC SILT (1 cm layer)
olive black (5Y 2/1)
Slide 3-60
40% feldspar
20% pyroxene
20% glass shards
SILT BEARING DIATOM RICH CLAY
10% claydark greenish gray (5GY 4/1)
TR diatoms
Slides 3-80 and 4-80
10% other
15% diatoms'5% silt
80% clay

DIATOMACEOUS CLAYEY SILT
olive gray (5Y 4/1)
Slide 4-145
40% diatoms
40% silt
20% clay
Explanatory notes in Chapter 1

404

XR 2-140
70% amorph.
8% quartz.}J p ! a 9H/; """?* c h l ° r
1/o m o n t

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3
Grain
Densityi i i i i ' • ' ' i

POROSITY,*
100
I

CM
-0

I

I

I

I 1

SECTION

M
On

1-

-25

2-

-50
3-

4-75

5-

-100

6-

7-

-125

8-

-150

190-12-1 190-12-2 190-12-3 190-12-4

405

SITE 190
Site 190

Hole

Core 13

Cored Interval.- 328-337

LITHOLOGIC DESCRIPTION

Note: interbedding is shown diagrammatically

Basic lithology:
Interbedded (5-20 cm layers)
VITRIC ASH
SILT and CLAY BEARING
light brownish gray (10YR 6/1) DIATOM OOZE to SILT BEARING
CLAY RICH DIATOM OOZE
olive gray (5Y 4/2 - 5/1)
and

VITRIC ASH
light olive gray (5Y 6/1)

DIATOMACEOUS SILTY CLAY
dark greenish gray (5GY 4/1)

VITRIC ASH
light graytop is biotite bearing, feldspar rich
Slide 1-105
90% diatoms
10% silt/clay

Slide 2-50
75% diatoms
5% silt
20% clay
Explanatory notes in Chapter 1

406

Slide 1-115
45% diatoms
25% silt
35% clay
Core Catch
D A G
N _ _
R R M
s F M

PF
BF

F

XR 2-60
79% amorph
6% quartz
4% plag.
8% mica
1% chlor.
2% mont.

SITE 190

WET-BULK DENSITY, gm/cc
1
2
3
11 i i i i i i i i i i i

POROSITY,%
TOO
0

> i i

SECTION
CM

i 11

ro

Grain
Density

"

1-

-25

2-

-50
3-

4-H

-75

5-

-100

6-

-125

8-

1—150

190-13-1 190-13-2 190-13-3

407

SITE 190

Site 190

Hole

Core 14

Cored Interval:421-430

VITRIC ASH
yellowish gray (5Y 8/1)

Basic lithology
SILT BEARING DIATOMACEOUS CLAY
light olive gray - olive gray (5Y 5/1 - 3/2)
various grayer and browner shades

semi-indurated, burrowed

numerous thin (<l-4 cm) layersof FELDSPATHIC SILT containing up
to 30% pyritized diatoms, olive black (5Y 2/1)

average composition of basic lith.
30% diatoms
10% silt
60% clay

VITRIC ASH
brownish gray (5YR 4/1)
XR 2-130, 6-10
86%97% amorph.
4%
1% quartz
4%
1% plag.
2%
mica
TR
TR chlor.
2%
1% mont.
TRpyriteTRamphib.

408

Core Catcher:
D
C G
pp R
BF

R

N
R
S

R
R

M
M

SITE 190
WET-BULK DENSITY, gm/cc
1

2

I i i i i i • i i > i • > > ' i i • •POROSITY,%
100
0

SECTION

3
CM
-0

I

Grain
Density
-32
3 o
M
O-i

1-

-25

2-

-50
3-

4-75

5-

-100

6-

7-

-125

8-

9-1
-150

190-14-1 190-14-2 190-14-3 190-14-4 190-14-5 190-14-6

409

SITE 190
S i t e 190

HoleCore 15

Cored I n t e r v a l : 6 0 9 - 6 1 8

FOSSILCHARACTER

LITHOLOGY

LITHOLOGIC DESCRIPTION

XR 1-130
64% amorph.
5% quartz
12% plag.
16% mica

VOID
0.5-

Core Catcher
D A G
CLAYEY DIATOM OOZE
olive gray (5Y 4/1)

N _ _
R R M
S F M
PF _

2% chlor.
1.0--~-

semi-lithified, burrowed
VITRIC ASH
DIATOM BEARING LIMESTONE
light olive gray (5Y 6/1)

CoreCatcherCore
Catcher

LITHOLOGY

LITHO.SAMPLE

Cored Interval:618-627

DEFORMATIONMETERS

Core 16

SECTIONPRES.

ABUND.

Hole
FOSSILCHARACTERFOSSIL

ZONE

AGE

Site 190

LITHOLOGIC DESCRIPTION

core catcher sample only:
1) CLAY olive gray (5Y 3/2)
contains partially dissolved diatoms

2) 2 pieces of MUDSTONE (~5 cm diam.)
3) LIMESTONE
Explanatory notes in Chapter 1

410Core Catcher:
D R M
£
K

-

-

s

- -

p

l

"

Dr

-

SITE 190
WET-BULK DENSITY, gm/cc
1

2

I i i i • i ' ' ' ' i ' • ' • i ' 'POROSITY,%
100
0

SECTION
CM
-0

3
' l

Grain
Density
|2o
u

{
H

-25

-50

j

-75

-100
6-

7-

i

hl25
8-

(c^TJr 3 **

9-150

1

I•IIIM

190-15-1

411