16. SITE 58
Shipboard Scientific Party1
SITE DATA
Occupied: July 28-30,1969.
Position: North flank of Caroline Ridge:
Latitude: 9° 14.l'N. Longitude: 144° 25.l'E.
Water Depths: 4503 meters (58.0, 58.1).
4486 meters (58.2).
Holes: 58.00 (on drillers record 58.0) cores none.
58.0 (on drillers record 58.1) 1 core.
58.1 (on drillers record 58.2) 3 cores.
58.2 (on drillers record 58.3) drill pipe stuck
and shot off; 1 core.
Total Depth: 569 meters, probably in Oligocene or
early Miocene basalt.
MAIN RESULTS
At this site, drilled on the flat sea floor at the north
flank of the Caroline Ridge, a flat, smooth basement
underlies early Miocene sediment. While no cores were
recovered from the basement, its drilling characteristics
and the recovery of fresh diabasic basalt chips from the
bumper sub make it highly probable that it is the same
basaltic basement that was cored at Site 47.
The sediments at this site are pelagic oozes with some
volcanic admixture, but are further characterized by
sands and by pebbles of reef-derived carbonate and of
volcanic glass and vesicular basalt. This site lies in a
submarine valley leading from volcanic banks and islands and atolls, and is probably an avenue for currents.
BACKGROUND
On crossing the Mariana Trench, out of the Philippine
Sea into the Pacific Ocean proper, old ocean floor comparable to that which had been drilled at Sites 51 and
52 was expected to be found. Hopefully, it might have
proved to be less cherty and more penetrable here. Yet
what was found in the area of Sites 55, 56 and 57
1
B. C. Heezen, Lamont-Doherty Geological Observatory; A. G.
Fischer, Princeton University; R. E. Boyce, Scripps Institution
of Oceanography; D. Bukry, U.S.G.S. La Jolla; R. G. Douglas,
Case Western Reserve University; R. E. Garrison, University
of California, Santa Cruz; S. A. Kling, Cities Service Oil Company; V. Krasheninnikov, Academy of Sciences of the U.S.S.R.;
A. P. Lisitzin, Academy of Sciences of the U.S.S.R.; A. C.
Pimm, Scripps Institution of Oceanography.
showed an ocean floor apparently more closely allied
to that of the Philippine Sea—a basaltic surface overlain
by a late Oligocene-early Miocene section of pelagic sediments. The next endeavor was to find the old Pacific
crust to the northeast, in order to finally penetrate it
more deeply, and also in order to define the boundaries
of these crustal provinces.
Accordingly, the ship steamed northeast on a course of
060, coming off the Caroline Ridge terraces onto flat
sea floor at a depth of about 4200 meters. The sediments
essentially disappeared, along our track, and then appeared again with a somewhat different character,
showing a well defined middle opaque zone on the profiles. Site 58 (Figures 1 and 2) was staked where the
sediments showed a thickness of some 0.18 seconds.
OPERATIONS
The beacon was dropped at Site 58 at 1030 hours,
July 28. Hole 58.0 (drillers Hole 58.1) was spudded at
1930 hours at a depth of 4503 meters and encountered
a very hard and unexpected layer at 20 meters, whereupon tools were pulled back to mudline, and a new
hole (58.0-drillers Hole 58.1) was spudded at 2130
hours and a core was cut but yielded almost no recovery. The hard spot was not encountered.
Pipe was again pulled back to mudline, and 58.1 (drillers Hole 58.2) was spudded at 2400. A surface core
retrieved shallow-water-derived carbonate sand and pebbles. Mud was spotted to hold the sandy and pebbly
upper sediments from collapsing into the hole. The
base of the sediments was encountered, but an attempt
to core the underlying material from 565 to 569 meters
yielded no recovery.
Pipe was pulled back to mudline, the ship was offset
450 meters and Hole 58.2 (drillers Hole 58.3) was
spudded at 1300 hours, July 29, at a water depth of
4486 meters in yet another attempt to recover basement. A core was cut in Miocene sediments, and during
its retrieval the hole collapsed, filling the lower 70
meters of drill pipe with carbonate sand and pebbles.
Pipe was worked for 4 hours without effect, and was
shot off with a Schlumberger device at a bumper sub,
whereupon the site was abandoned at 0900 hours,
July 30.
539
TAU
1500
-
2000
-
-
36400
36300
36200
23 July 1969
2500
1
18
19
25 July 1969
I
10 01
I
, | I
I
I
I
I
I
I
I
I
I
I
I
i
12
Figure 1. Challenger bathymetric and magnetic profile at Site 58.
NATURE OF THE SEDIMENTS
Of five cores attempted in the three holes at Site 58,
two were successful (Core 1, Hole 58.1, and Core 1,
Hole 58.2), one recovered only a core catcher sample
(Core 1, Hole 58.0), and two had no recovery (Cores
2 and 3, Hole 58.1).
Hole 58.0
The single core from this hole was drilled from 15.2 to
20.1 meters below mudline, but only a catcher sample
was recovered. This consists of gravel to coarse sand
size sediment composed of: (a) fragments of black basalt, palagonite, and volcanic glasses with a wide variety
of colors (black, dark green, olive-green, red and colorless); (b) subangular to subrounded grains of dense
white limestone that appears somewhat recrystallized;
staining tests indicate the presence of aragonite and
magnesium calcite in addition to calcite; (c) abraded
skeletal fragments of benthonic foraminifera, corals
(including Acropora), echinoid spines, and sponge spicules; (d) small amounts of sand-size feldspars and opaque
grains. Along with this coarse sediment is a small amount
of silty calcareous clay containing nannofossils, foraminifera and finely abraded fragments of bryozoa and
540
mollusks. The grain size and faunal composition of this
sediment suggests redeposition.
Hole 58.1
Core 1 in this hole was drilled from mudline to 9.1
meters but recovered only about 3.75 meters of highly
variable calcareous and siliceous oozes. The upper few
decimeters of the core are very pale brown, soft diatom
ooze composed almost entirely of delicate tests of
Ethmodiscus (Chapter 38). The remainder of Section 1
is white chalk ooze and pale brown nannoplankton
marl ooze with abundant nannofossils and clay minerals,
and common to rare amounts of diatoms, Radiolaria,
and sponge spicules. At the top of Section 2 is a 20centimeter layer of dark yellow-brown calcareous clay
with well preserved siliceous microfossils. This unusual
sediment contains abundant nannofossils and finegrained anhedral calcite of skeletal or authigenic origin.
Also present are significant amounts (10 to 15 per cent
each) of lath-shaped zeolites, Radiolaria, clay minerals
and limonitic grains, and smaller amounts of diatoms,
sponge spicules and planktonic foraminifera.
The remainder of Section 2 and the top half of Section
3 are brown to pale brown and yellow-brown carbonate
9° N
9° N
I
145° E
Figure 2. Bottom soundings in area of Site 58.
ooze composed of abundant anhedral calcite grains and
nannofossils. The anhedral calcite is in the fine silt to
clay size range; some of it appears to be finely abraded
skeletal material, but the origin of most is indeterminate. Also present in this carbonate ooze are common
planktonic foraminifera and small amounts of clay minerals, zeolites and limonitic grains. The lower 80 to 85
centimeters of Section 2 are very pale brown, calcareous
sandy silt composed largely of abraded skeletal fragments of pelecypods, echinoderms and benthonic foraminifera, along with rare planktonic foraminifera and
volcanic glass shards.
Cores 2 and 3 were attempted below 140 meters subbottom depth but had no recovery.
Hole 58.2
The single core from this hole was drilled between 136.6
and 143.3 meters subbottom and recovered about 8.8
meters of sediment. The upper 4.3 meters (Sections 1
to 3) of this core are mainly pale brown nannoplankton
chalk ooze and marl ooze, the lower 4.5 meters are pale
brown nannoplankton chalk and marl ooze with thin
interbeds of dark volcanic ash. Near the top of the core
is a 45 to 50 centimeter thick layer of gravel with angular
to rounded fragments of white and brown limestone,
and dark gray to brown porphyritic and amygdaloidal
volcanic rocks. The nannoplankton ooze and marl of this
core is unusual compared to other sediments of this
type encountered on Leg 6 in that significant amounts
of well-preserved siliceous microfossils are present
(Chapter 38) in the carbonate sediment; sponge spicules
are unusually abundant, and radiolarian tests are common to abundant. The volcanic ash occurs in layers
from a few centimeters to over 40 centimeters thick and
contains 70 to 80 per cent of volcanic glass, much of
which is vesicular and most of which is an olive green
color and of basaltic composition (n = 1.55 to 1.585).
The sedimentation pattern evident at Site 58 suggests
intervals of pelagic sedimentation alternating with episodes of resedimentation from adjacent areas; the latter
type of deposition was probably responsible for introduction of the gravels and the shallow-water skeletal
material. This pattern could explain, in addition, the
apparently high sedimentation rate for Miocene sediments at this site, which in turn might in part be responsible for the abundance and excellent preservation
of siliceous microfossils in the calcareous oozes, particularly those in Core 1 of Hole 58.2.
541
TABLE 1
Summary of Coring at Site 58
Interval Cored
(below mudline)
Recovery
(m)
Core No.
(ft)
58.0-1*
58.1-1*
50-66
15.2-20.1
0-30
58.1-2*
58.1-3*
58.2-1 * a
565-569
0.0-9.1
172.2-173.4
173.4-
569-569
448-470
136.6-143.3
(ft)
(m)
1
15
0.3
4.6
0
0.0
0
30
0.0
Hole 58.2
Only one core of Oligocene nannoplankton radiolarian
sponge spicule ooze was recovered from Hole 58.2
within 136 to 145 meters below the mudline. Sections
1 through 4 emitted 100 to 500 gamma ray counts
with an average of about 250 counts/7.6-cm core
segment/1.25 minutes. The count of 500 was caused
by a wet-bulk density increase. Sections 5 and 6 had
gamma ray counts ranging from 200 to 1100, with an
average of about 500. The increase in natural gamma
radiation in Sections 5 and 6 was associated with abundant volcanic ash in the ooze, and high wet-bulk density
variations.
9.1
Porosity, Wet-Bulk Density, and Water Content
Water Depth: 4502.5 meters (14,772 feet)
a
4486.4 meters (14,719 feet)
* Scientific Log
(this log)
Not listed
58.0
58.1
58.2
Drillers
58.0
58.1
58.2
58.3
PHYSICAL PROPERTIES
These sediments were disturbed during coring operations, thus in situ physical properties are not necessarily represented.
Natural Gamma Radiation
Hole 58.1
One core containing 4.6 meters of Pleistocene (reworked
Pliocene-Miocene) diatom and nannoplankton ooze was
recovered from 0 to 9 meters at Hole 58.1. The upper
two sections (3 meters) had extremely high gamma
radiation averaging 3000 counts/7.6-cm core segment/
1.25 minutes. The total ranges were 2500 to 5000
counts in Section 1, and 500 to 5200 counts in Section
2. The sediment here was a Pleistocene Ethmodiscus
diatom ooze grading down into predominantly chalk
ooze. In Section 3 (3 to 4.5 meters) the natural gamma
count ranged from 300 to 1100 counts, with an average
of about 700 counts/7.6-cm segment/1.25 minutes.
The sediment here was sandy skeletal calcareous silt.
The source of the high (nearly twice as high as any
other sediment on Leg 6) gamma radiation close to the
surface was not readily apparent, but it could be caused
by the presence of one or more radioactive isotopes
with relatively short half lives. Again, as at some other
sites, the Pleistocene diatoms appeared to be associated
with high gamma radiation.
542
Hole 58.1
Drilling in Hole 58.1 between 0 and 9.1 meters below
the sediment surface recovered sediment of widely
differing lithologies. These were Pleistocene diatom
ooze, nannoplankton ooze, radiolarian-zeolitic clay, and
calcareous skeletal silts. In the one core from this hole
ranges of porosity, wet-bulk density, and water content were 42 to 94 per cent (?), 1.10 (?) to 1.92 g/cc,
and 27 to 63 per cent, respectively. Section 1 (0 to 1.5
meters below the sediment surface) had maximum
porosities about 90 per cent in the highly disturbed
Ethmodiscus diatom ooze and a minimum of 62 per
cent in nannoplankton chalk ooze; corresponding wetbulk densities ranged from 1.18 to 1.64 g/cc. A water
content sample of chalk ooze yielded 63 per cent water.
The sediment in Section 2 (1.5 to 3.0 meter depth)
consisted of radiolarian zeolite clay, and non-skeletal
silt-size carbonate with about 25 per cent nannoplankton. Porosities ranged from 62 to 85 per cent (?) and
wet-bulk densities from 1.30 to 1.62 g/cc in the radiolarian zeolite ooze, while the carbonates were 43 to 62
per cent and 1.62 to 1.93 g/cc. A sediment sample at
128 centimeters in Section 2 had a porosity of 52 per
cent, wet-bulk density of 1.96 g/cc, and water content
of 27 per cent.
The lithology in Section 3 (3.0 to 4.5 meters) had an
abrupt change at 65 centimeters. The upper part was
non-skeletal carbonate ooze with porosities ranging from
56 to 72 per cent and wet-bulk densities from 1.46 to
1.72 g/cc. The lower part of Section 3 was a skeletal
sandy silt of mainly echinoderm-pelecypod fragments
which had a maximum density of 1.95 g/cc and a minimum porosity of 42 per cent.
Hole 58.2
Sediment recovered from Hole 58.2 at 135 to 144
meters below mudline was an Oligocene nannoplanktonradiolarian-sponge spicule ooze with porosities ranging
from 50 to 84 per cent (?) (1.28 to 1.80 g/cc). The
interval from 1370 to 1374 meters is an ooze containing abundant pebbles of limestone and volcanic rocks
with a maximum density of 2.05 g/cc and a minimum
porosity of 32 per cent. The porosities of the rocks of
course are much less as the GRAPE unit averages the
rock porosity with the porosity of the sediments surrounding them. The typical sediment of this core was
nannoplankton marl ooze with radiolarians and sponge
spicules in some areas. Its porosity was typically about
70 per cent (1.45 g/cc). Volcanic ash layers in this sediment generally had lower porosities, as low as 49 per
cent. The water content of sediment samples from the
core recovered in Hole 58.2 ranged from 46 to 57 per
cent.
Penetrometer
Sound Velocity
Hole 58.2
Oligocene nannoplankton oozes with intervals of marl,
radiolarians, ash, and sponge spicules were cored at
Hole 58.2 at a depth of 136.6 to 143.3 meters. Penetration of the needle ranged from 24 to 81 X I0"1 millimeters with an average of 49. It appears that the ash
layers were penetrated more easily than the radiolarian
nannoplankton beds, the greater resistance in the latter
may be caused by an intermeshing of the radiolarian
tests. Typically, pure nannoplankton oozes were penetrated more easily.
Hole 58.1
Sediment sound velocities (through Pleistocene Ethmodiscus diatom ooze, nannoplankton ooze, radiolarian
zeolitic clay and calcareous skeletal sands in Hole 58.1,
(0 to 9 meters) ranged from 1.51 to 1.78 km/sec with
an average of 1.58 km/sec. The highest velocity (1.78
km/sec) was recorded in a dense skeletal silt (2.9 to
3.8 meters below the sediment surface) consisting almost entirely of pelecypod and echinoderm fragments.
The yellow-brown chalk ooze (1.0 to 2.0 meters),
characterized by non-skeletal carbonate with 25 per
cent nannoplankton, had low to moderate velocities of
1.51, 1.60 and 1.64 km/sec. The remainder of the
velocities were, in general, lower (1.51 to 1.55 km/sec)
in the nannoplankton chalk ooze and radiolarian zeolite
clays (0 to 0.5 meter).
Hole 58.2
In Hole 58.2, sound velocities measured through Oligocene nannoplankton-radiolarian-sponge spicule ooze
(from 135 to 144 meters below the sediment surface)
averaged 1.53 km/sec and had a complete range from
1.46 to 1.58 km/sec. There was a very slight increase
in sound velocity in the lowermost two sections where
volcanic ash was abundant, creating denser sediment.
Thermal Conductivity
Holes 58.1 and 58.2
Two thermal conductivity measurements were made in
Pleistocene echinoderm pelecypod silt and Oligocene
nannoplankton-radiolarian-sponge spicule ooze from
Holes 58.1 and 58.2. The Pleistocene skeletal silt at a
depth of approximately 3.4 meters below mudline in
Hole 58.1 had a thermal conductivity of 2.78 X I0"3
cal^C"1 cm"1 sec"1. In Hole 58.2 Oligocene ooze at a
depth of 139.0 meters below mudline had a higher
thermal conductivity of 3.68 X lO^cal^C^cm^sec" 1 .
Hole 58.1
Pleistocene Ethmodiscus diatom ooze, nannoplankton
ooze, radiolarian zeolite clay and calcareous skeletal
sands (0 to 4.5 meters) were penetrated completely with
a minimum of 34 X I0"1 millimeters. The Pleistocene
Ethmodiscus ooze was penetrated 67 X I0"1 millimeters
with complete penetration in the underlying nannoplankton marl oozes of Section 1. The needle completely
penetrated the brown radiolarian zeolite clay at the top
of Section 2, but below it, brown silty chalk ooze had
penetrations of 34 to 88 X I0"1 millimeters.
CONCLUSIONS
The oceanic crust at Site 58 appears to be closely allied
to that of the Caroline Ridge: A smooth, hard basement is overlain by Oligo-Miocene sediments. While no
core was recovered from the basement, its drilling characteristics and the presence of fresh chips of diabasic
basalt in the bumper sub make it extremely probable
that the basement is very much like that at Site 57.
The basalt (in the bumper sub) at Site 58 differs from
that cored at Site 57 in the distinct greenish cast of its
feldspars.
An unusual feature of the sediments at Site 58 is the
admixture of shallow water clasts. The pelagic sediments are nannoplankton oozes with an admixture of
diatoms and Radiolaria (including some Ethmodiscus
diatomites). The admixed clasts consist of granules and
pebbles of vesicular basalt, glass, skeletal material (large
foraminifera, shell fragments, echinoderm debris, coral
fragments), and lithified limestone. According to Sachs
(personal communication) the larger foraminifera are
mainly of late Oligocene to Miocene age, and none
are older. The clasts occur partly in well-sorted sands,
partly as pebbles dispersed in ooze matrix—reminiscent
of the Cretaceous pebbly mudstone facies at Sites 4
and 5, Leg 1. Site 58 lies in a branched submarine valley extending to the flanks of Faraulep Atoll, Gaferut
Island, and a number of banks which are of joint volcanic reef growth origin. Presumably this valley serves
as an avenue for turbidity currents and other currents,
and as an avenue for sediment transport.
543
HOLE 58.0. 58.1 & 58.2
AGE
LITHOLOGIC DESCRIPTION
SERIES-SUBSERIES
DIATOM OOZE p a s s i n g down i n t o NANNOPLANKTON MARL/CHALK OOZE,
CALCAREOUS CLAY w i t h s i l i c e o u s f o s s i l s , CARBONATE OOZE, and f i n a l l y
sandy SKELETAL S I L T ; sediments range from p a l e brown t o dark y e l l o w
brown
PLEISTOCENE
Gravel and sand s i z e m a t e r i a l o f : LIMESTONE, FORAMINIFERA, CORAL,
ECHINOID, BASALT, VOLCANIC GLASS, SILTY CLAY
EARLY PLIOCENE
to MIDDLE MIOCENE
Sponge - RADIOLARIAN-NANNOPLANKTON MARL OOZE, w i t h t h i n ash b e d s ,
and i n p l a c e s pebbles o f LIMESTONE and VOLCANIC ROCKS
LATE OLIGOCENE
120
140
280
Figure 3. Summary oflithology in Holes 58.0, 58.1, and 58.2.
544
HOLE 58.0. 58,1 & 58.2
DEPTH
H 0'N
LE
NATURAL GAMMA
RADIATION
RADIATION
WET-BULK
TL
DENSITY
DENSITY
WATER CONTENT
ND
SOUND
SOUD
VELOCITY
OCI
THERMAL
PENETROMETER
CONDUCTIVITY
O I V I T Y
COUNTS/7.6cm/1.25min
5000
1.4
1.8
2.2
20
40
60
80
100
1.6
1.8
2.0
2.2
2.0
3.0
4.0
0
100
200
300
58.1
58.2
*O = LABORATORY- ATMOSPHERIC BACKGROUND COUNT.
Figure 4. Summary of physical properties in Holes 58.0, 58.1, 58.2.
545
er
UJ
CD
<X
CO
UJ
LEG
CORE
LITHOLOGIC DESCRIPTION
N E
-7
-12
:•i3
Small amount (15 g) of sediment
recovered in bottom of core barrel
and core catcher. This is a mixture
of gravel and coarse sand-size
material of following components:
1. Subangular to subrounded grains
of white limestone. Limestone
is opaque and partly recrystallized. Staining tests indicate
a composition: calcite 60%
aragonite 35%
Mg calcite 5%
2. Free specimens of benthonic
foram, coral fragments
(Acropox>a), and echinoid spines,
few sponge specules
3. Volcanic fragments of:
4.
5.
black basalt (< 8 mm diameter)
Black, dark green, olive green,
red, and clear glass
White and yellow-black palagonite
Small amounts of feldspar and
minute magnetite grains
Yellowish brown (10YR 5/4) s i l t y
clay with nanno, coral, bryozoa
and mollusc, also rare foram
cc
Figure 5. Summary oflithology in Hole 58.0 Core 1.
546
HOLE
DEPTH
58.0
15.2-20.1 m
LEG
CORE
HOLE
~
DEPTH 16.220.1
NANNOPLANKTON
FORAMINIFERA
The mixed assemblage of
Samples of sand and clay
Miocene and Pliocene
from the core catcher con-
planktonic Foraminifera was
tain a mixed assemblage of
met in the core catcher
Miocene and Pliocene
sample.
species.
Miocene species: Globoro-
sent that became extinct
tália menca>diij G. scitul<Zj
during the Miocene are
G. mayevi,
Cyaloaoccolithina neogamma-
Sphaeroininell-
tiorij Disaoaster
drina altispir>a3 Biovbutina
and Sphenoli•thus heteromor-
bilobata, Candorbulina
phus.
universe
present, indicating an
Pliocene species: Glóbovo-
upper Miocene to lower
talia tumida-i G. infiata,
Pliocene range, include
or>assaformis, Sphaevoidinella
dehisσens, Globigerinoides
None.
The species pre-
opsis gvimsdalei, Globoqua-
G.
RADIOLARIA
deflandrei,
Other species
Ceratolithus vugosus3 Cyolooooaolithina
macintyrei.
aonglobatus, G. saooulifera,
Disaoaster> quintatus, and
G. rubrwrij Pulleniatina
D. suroulus.
obliquiloautata.
Figure 6. Summary of biostratigraphy in Hole 58.0 Core 1.
547
UJ
LU
CO
UJ
_l
<
UJ
OL
<
§
u
CO
<I
ISI b Cr
LU
co
-1
-2
4
5
-6
8
9
3+0
12
4: 13
14
o
o
5
:•I6
:
5-
S
CO
LEG
CORE
I
I
33 64
CALCAREOUS CLAY with SILICEOUS
FOSSILS
Dark yellow brown (10YR 4/4)
Non-Skeletal Calcite A
Nanno C
Spcl R-C
Foram R
Diatom R-C
Zeolite C
Clay C
Rad C
Glass R
Limonite, Barite C
27
CARBONATE OOZE
Pale brown, brown (10YR 6/3 - 5/3)
Indeterminate Carbonate A
Foram C
Nanno A
SKELETAL SAND
Very pale brown (10YR 8/3)
Pelecypod and Echinoid fragments D
Benthonic foram C
Planktonic foram R
Glass R
:
CC
Figure 7. Summary oflithology in Hole 58.1 Core 1.
548
3 2
24 74 63 68
NANNO MARL CHALK OOZE
Pale brown (10YR 4/3), light gray
(10YR 7/2), and white (10YR 8/2)
to
U0
s
DIATOM {Ethmodisous) OOZE
Very pale brown (10YR 8/3) with
thin deformed layers of dark grayish
brown (10YR 4/2) diatom ooze
8:
O
o
CO
Section 3 very watery and not split
6;
7
0.0-9.1 m
LU
Q
--I9
•S
58.1
LITHOLOGIC DESCRIPTION
:-iδ
T3
(1)
HOLE
DEPTH
86
93
CORE: 58.1-1
DEPTH
NATURAL GAMMA
IN
RADIATION
CORE
H
M
">
WET-BULK
DENSITY
COUNTS/7.6cm/1.25min
0
WATER CONTENT
AND
POROSITY
g/cc
5000
1.4
1.8
%wt
2.2
20
40
SOUND
VELOCITY
THERMAL PENETROMETER
CONDUCTIVITY
X10" J
cal/(°C cm sec)
% vol
60
80
100
r~i i i i i i i i i i i i i i i r
2.0
2.2
20
3.0
4.0 0
X10'
100
200
300
" i
2-
5-
7-
I
1
*O = LABORATORY-ATMOSPHERIC BACKGROUND COUNT.
Figure 8. Summary of physical properties in Hole 58.1 Core 1.
549
LEG
CORE
HOLE -.1
D E P T H 0.0.9.,
FORAMINIFERA
RADIOLARIA
NANNOPLANKTON
Mixture of Pliocene and
A mixture of ages and
Radiolaria are very rare in
Miocene deep-water and
lithologies is present.
this core.
shallow-water planktonic and
Most samples appear to be
fiable species are from the
benthonic Foraminifera is
Pliocene with some Miocene
middle and/or lower Miocene,
present - Pulleniatina
mixing.
suggesting reworking or
obliquiloβulata, G. tosa-
include Ceratolithus vugosus, contributions from exposed
ensis3 G. tumida, G. aoos-
Coooolithus pateous,
Species present
older sediments.
taensis kumerosa, G. arassa- Cyalooooaolithina teptopovuQ, TOP:
not examined.
formisj G. ungulata, G.
C. maaintijvei, C. neogamma- BOTTOM: Cyvtocapsella
hirsuta.j G. inftata3 G.
tion, Disaoaster bvouweri3
oultvata, Candeina nitida,
D. ahallengevi_, D. deftan- and Cannartus pvismatious.
Glogiber>inoides rubev, G.
dveiy Retioulofenestva
eornuta, Doroadospyris sp.3
trilobus, G. oonglobatus, G. pseudovanbilioay Sphenolithus
saoculifera3 G. fistulosus,
hetevomorphus, Tv•Lquetvov-
Sphaevoidinella dehisoens3
habdülus rugosus. A light
Sphaevoidinellopsis
brown clay from the core-
gvinsdáleiy Globoquadrina
catcher sample, however,
altispiva3 G. dehiscens.
contains a uniform assem-
Streblus beocca>ii>
blage of the upper
Amphisteg•ina lessσnii,
Pleistocene Gephyrooapsa
Miogypsina sp. sp.
ooeaniβa Zone with Cerato-
Pliocene species predominate.
lithus ar•istatuSj Cyaloooacolithina leptopoz>us3
Cyclolithella annula, and
Gephyrocapsa ooeaniβa being
present.
Figure 9. Summary of biostratigraphy in Hole 58.1 Core 1.
550
The few identi-
LEG
CORE
HOLE
DEPTH
FORAMINIFERA
NANNOPLANKTON
The core catcher sample
Only a trace of material was
belongs to the upper part of
recovered from the core
the Globorotalia kugleri
catcher. The assemblage of
Zone, lower Lower Miocene
species present includes
(or upper Upper Oligocene of
Coooolithus eopelagieus3
Bolli s zonal scale, 1957).
Cyoloooooolitkus neogamma-
The assemblage of planktonic
tiont Disooaster deflandrei3
Foraminifera consists of
D. druggi> and Triquetror-
numerous Globorotalia
habdulus oarinatus Zone,
kugleri, Globigerina
and in particular the upper
juvenilis, G. bradyi3 G.
part of the zone or the
angustiumbilicata,
Disooaster druggi Subzone.
RADIOLARIA
None.
Cassigevinella ohipolensis
and infrequent Globigerina
ouaohitaensis, Globoquadrina
praedehisoensj Globigerinoides trilobus primordius.
Figure 10. Summary of biostratigraphy in Hole 58.1 Core 2.
551
LEG
CORE
LU
<
o
LU
DEPTH
1
3β.6-143.3m
CO
2
d
5 g
58 S E
HOLE
2^
LITHOLOGIC DESCRIPTION
CO
For d e t a i l see section descriptions
-2
-3
Pebbles of white r e c r y s t a l l i z e d
limestone, dense f i n e grained brown
limestone, and dark gray-brown porphy
r i t i c and amygdaloidal VOLCANIC ROCKS
i n pale brown ooze
83
52 47 46 71
-4
t
-6
-7
-8
-9
<-J>
o
1
CJ3
-12
O
LU
:
4
-14
-16
5-
-17
:•i8
--I9
Very pale brown (10YR 8/3) NANNO
CHALK OOZE
Nanno A
Spcl C
Rad C
Foram R
Glass R Clay R
49 63
Thin (1-2 cm) moderate o l i v e brown
ash a t 82 cm i n section 1
Sections 2-5: Siliceous f o s s i l s
comprise 30-40% of sediment
SPONGE-RAD-NANNO MARL OOZE
Nanno A
Clay C-A
Spcl C-A
Glass C
Rad C-A
Foram R
w i t h , i n sections 4 and 5, ASH
very dark gray (10YR 3/1), r a r e l y
dark grayish brown (10YR 3/2), and
gray (10YR 5/1).
Ash occurs as numerous \/ery thin
(1-3 mm) layers and as thicker
(5-15 cm) compact, harder beds
Average composition:
Glass C (olive green - basaltic)
Feldspar "
Clay R
Opaques
Pyroxene
Mica
Zircon
Nanno R-C
Foram (R - in thicker units only)
44 48 51
55
50 43 47 58
82 10
20
:
:
46 73
•2I
-22
24
Brown (10YR 4/3) and yellowish
brown (10YR 5/4) SPONGE RAD OOZE with
NANNO
Spcl A
Rad A
Nanno A Glass C
(basaltic)
Dark grayish brown (10YR 4/2) ASH
Glass is predominantly clear and
pale brown and of andesitic
composition
8:
cc
Figure 12. Summary of physical properties in Hole 58.2 Core 1.
552
57 13
CORE: 58.2-1
DEPTH
NATURAL GAMMA
IN
RADIATION
CORE
WET-BULK
DENSITY
COUNTS/7.6cm/1.25min
SOUND
VELOCITY
WATER CONTENT
AND
POROSITY
g/cc
% wt
% vol
THERMAL PENETROMETER
CONDUCTIVITY
km/sec
cal/("C cm sec)
CP
5000
i
i
i
r
1.4
i
1.8
2.2
20
40
60
80
100
1.6
i i i i i i i i i i i i i i i i r
1.8
2.0
i
i
2.2
i
i
I
2.0
3.0
4.0
i
I
i
0
100
200
300
I O i
i
i
1 -
o
o
5-
7-
*O = LABORATORY-ATMOSPHERIC BACKGROUND COUNT
Figure 11. Summary oflithology in Hole 58.2 Core 1.
553
LEG
HOLE
CORE 1
DEPTH
136.6-143.3 m
FORAMINIFERA
NANNOPLANKTON
RADIOLARIA
Throughout the core assem-
Upper upper Oligocene assem-
This core contains Radiolaria
blages of the Globorotalia
blages of the Triquetrorháb-
of the lower lower Miocene
kugleri Zone present, lower
duluβ carinatus Zone are
Caloσyoletta Virginia Zone.
Lower Miocene ( or upper
present throughout the core.
They are abundant and well
Upper Oligocene of Bolli's
Species present include
preserved.
zonal scale, 1957).
Coooolithus sp. aff. C.
TOP: Cαlooyolettα Virginiat
Among planktonic foraminifers biβeotuβ, Cyσloeoocolithina
Cyrtocαpsellα oornutα,
are numerous Globorotalia
neogammation> Diaooaβter
Doroαdoβpyris αteuchuβ,
kugleri3 Globigerina bradyi,
deflandreiy Sphenolithus sp.
Cαnnαrtus priβmαticus, and
G. juvenilia, G. angustium-
aff 5. belermoβj S. mori-
Lyβhnocαnium bipes.
biliaata, Caββ•igeri•nella
formis, and Triquetrorhxb-
BOTTOM: Cαlooyolettα
σhipolensis accompanied by
dulus oarinatuB.
virginiβ, Cαnnαrtus pri&mαti-
rare Globigerinita uniaava
ouβ, Cyrtooαpβellα oornutα,
and Globorotalia siakensis.
and Dorcαdoβpyris αteuohus.
Figure 13. Summary
554
«
of biostratigraphy in Hole 58.2 Core 1.
SECTION
—Ocm
1
•25
Plate 1. Photographs of Hole 58.1 Corel.
555
SECTION
— Ocm
Plate 2. Photographs of Hole 58.2 Core 1.
556