3. SITE 354: CEARA RISE The Shipboard Scientific Party1974/10/27 · 3. SITE 354: CEARA RISE The Shipboard Scientific Party1.Rio de Janeiro . 500 km Sdb Paulo at lat. 25 S ^Plateau

3. SITE 354: CEARA RISE

The Shipboard Scientific Party1

.Rio deJaneiro .

500 kmSdb Paulo at lat. 25°S

^Plateau<? 356/

> 20 0

45°W

SITE DATA

Date Occupied: 27 October 74 (1230Z)

Date Departed: 31 October 74 (1305Z)

Time on Site: 4 days, 35 minutes

Position: 05°53.95'N, 44°11.78'W

Accepted Water Depth: 4052 meters (drill pipe measurement)

Penetration: 900.0 meters

Number of Holes: 1

Number of Cores: 19

'K. Perch-Nielsen, Eidg. Technische Hochschule, Zurich, Switzer-land (Co-chief scientist); P.R. Supko, Scripps Institution ofOceanography, La Jolla, California (Co-chief scientist); A. Boersma,Lamont-Doherty Geological Observatory, Palisades, New York; E.Bonatti, University of Miami, Miami, Florida; R.L. Carlson, Uni-versity of Washington, Seattle, Washington; F. McCoy, Lamont-Doherty Geological Observatory, Palisades, New York; Y.P.Neprochnov, U.S.S.R. Academy of Sciences, Moscow, U.S.S.R.;H.B. Zimmerman, Union College, Schenectady, New York.

Total Length of Cored Section: 211.0 meters

Total Core Recovered: 119.0 meters

Principal Results: At Site 354 on the Ceará Rise, wepenetrated 886 meters of sediment above acousticbasement. The first one meter subbottom is Holocene (?)yellow-brown foraminifer-nannofossil ooze, overlying 47meters of Plio-Pleistocene nannofossil ooze which containsa significant detrital fraction. Marly oozes continue to 240meters, where a transition from ooze to chalk occurs inmid-Miocene. Foraminifer-nannofossil chalk of Mioceneto early Oligocene age extends to 550 meters, at whichdepth a regional reflector corresponds to an abrupttransition to marly diatom-nannofossil chalk whichextends to 630 meters (mid-Eocene). Blue-green marlynannofossil chalk extends to 805 meters (upper Paleocene-lower Eocene), gray nannofossil chalk with some red zonesto 850 meters (upper to middle Paleocene), and red marl oflate Cretaceous age to 886 meters. Acoustic basement wascored for 14 meters; 9.5 meters were recovered (a diabasic

CoredInt . Units Lithology Age

0-

800

900

45

SITE 354: CEARA RISE

basalt). Reflectors within the basement indicate a series offlows or sills with intercalated sediments.

Average sediment accumulation rate is 1.3 cm/1000 yr;this includes a cored hiatus in the mid-Miocene andperiods of slow accumulation, or hiatus, in the lateEocene-Oligocene and Late Cretaceous-middle Paleocene.

BACKGROUND AND OBJECTIVES

Site 354 is on the western edge of the Ceará Rise, apronounced topographic feature 150 miles east of theAmazon Cone in the western equatorial Atlantic(Figure 1).

A section of about 1 km of sediments conformablyoverlies this basement high. Sonobuoy data show anormal oceanic section under the rise, and refractionsfrom material with a 4.5 km/sec velocity come from adepth representing the acoustic basement (Embley andHayes, 1972), except in certain places where a 3.5km/sec layer forms the smooth acoustic basement(Kumar and Embley, in press). Internal reflections arerather diffuse within the rise sediments, but two can betraced throughout the rise; the shallower reflector canbe traced beneath the Amazon Cone (Figures 2, 4).

The Amazon Cone sediments buried a large area ofthe Ceará Rise during the late Neogene (Damuth andKumar, 1975; Kumar and Embley, in press). Results of

drilling at DSDP Site 142 on the southern flank of theCeará Rise (Figure 1) suggest cessation of pelagicsedimentation there in the middle Miocene (the holeterminated in sediment of this age) before burial oflower parts of the rise by abyssal plain sediments fromthe middle to late Miocene onward. Cores taken oncruises by Vema 18 and 25 and Conrad 8 and 13 on andin the vicinity of the Ceará Rise contain upperPleistocene pelagic sediments as well as turbidites; onecore (V 25/62) consists of a Miocene foraminifer ooze(Embley and Hayes, 1972).

Magnetic anomalies have not yet been recognized inthe equatorial Atlantic. A reasonable interpolationbetween spreading rates for the northern and southernAtlantic, however, gives an approximate age of 80 m.y.for the western edge of the Cearà Rise. Theanomalously shallow basement underlying the CearáRise is analogous to a section of the Sierra Leone Riseon the eastern side of the Atlantic. Both are boundednorth and south by the same fracture zones (theDoldrums at 8°N and one at 4°N—Cochran, 1973).Their older sections lie equidistant from the presentridge axis.

The scientific objectives at this site were:1) Biostratigraphy: To date the succession of

predominately pelagic and occasionally terrigenoussediments—of special interest at this site, where the

Figure 1. Base map, Site 354. Dashed line shows approximate morphological limits of Ceará Rise. Amazon Cone shown ascontours to 4500 meters. Hatched area delimits Mid-Atlantic Ridge province. Section CD of solid line marks location ofreference profile. Simplified from Kumar and Embley (in press).

46


Record No., Cruise RC16-03

I 4 5 9 1 4 6 0 I 4 61

I PROPOSED SITE462 1 - 3

.. . : • • • i •

C DFigure 2. Reference seismic reflection profile, Cruise RC16-03, Lamont-Doherty Geolo-

gical Observatory, Record 459, 0048 hrs. Section CD shown on Figure 1.

sedimentary sequence is probably one of the bestavailable for the western equatorial Atlantic.

2) To date the intermediate reflectors. One of thereflectors is traceable beneath the Amazon Cone.

3) To establish the nature and age of basement, sincethere is no basement-age information for this region,either from interpretation of magnetic anomalies orfrom drilling.

OPERATIONSWe approached Site 354 from the Vema Fracture

Zone on a course of 235°T. At 1004Z, 26 October 1974,we changed course to 270°T to reach a point fromwhich we could pass over the proposed site on thereference profile heading of 187°T (see Figure 2,segment C-D, record 459 of cruise Robert Conrad 16-03, Lamont-Doherty Geological Observatory). Wecompleted our turn onto the 187°T heading at 1039Z,reduced speed to 6 knots about four miles north of theproposed site, and came onto the Lamont track at1100Z, actually making good about a 176°T course (seeFigure 3).

The proposed site was located at 0048 hr on theLamont profile (see Figure 2), presumably because anintermediate reflector at about 0.5 sec is well developedhere. We elected to alter the position of the site slightly,for two reasons. First, other Lamont profiles in the areaand our own approach profile (Figure 4) show theintermediate reflector to be well developed regionallyand along our line of approach, obviating the necessityof locating the site at so precise a position as thatindicated on Lamont record 459. Second, the Lamontrecord indicates the proposed site is on a basementhigh. Although we thought hydrocarbon entrapmenthighly unlikely, we continued to a point off thebasement high. (Note that since the site was selectedjust before the beginning of the cruise, there was nottime to allow evaluation by the JOIDES AdvisoryPanel on Pollution Prevention and Safety).

We dropped the beacon at 1241Z while the ship wasunderway, retrieved geophysical gear, and returned toposition the ship over the beacon.

Stabilizing over the beacon was difficult because of avery strong current (averaged over the next several daysat 2.7 knots from 230°), winds at bad angles to thecurrent, problems with the positioning computer, andlack of generator power to one of the bow thrusters.After trying for seven hours, we positioned successfullyover the beacon at 1940A, 26 October, and beganrunning in the hole. Hole 354 was spudded at 1018Z, 27October 74. Water depth by PDR is 4045 meterscorrected; the bottom was felt at 4062 meters below therig floor. The drill pipe measurement was accepted,water depth is thus 4052 meters.

Since the objectives at this site were to penetrate tobasement (0.9 sec) as well as to obtain as complete asection as possible, all in limited time, intermittentcoring was necessary (see Table 1). We selected coredepths on the basis of the approach reflection profile,inferred lithologies and associated estimated velocities,measured seismic velocities on recovered samples, andexpected sedimentation rates and locations of probablehiatuses.

Cores 1 and 2 were obtained without circulation orrotation. In Core 3, circulation was broken once, inCore 4 twice. Cores 5 to 19 required pumping; theformation was predictably more difficult to drill withdepth, because of overburden compaction anddiagenetic cementation.

Another reason for the slow drilling rates, wethought, was that during the drilling of several pipelengths, the barrel might become partly or completelyfilled with core inadvertently collected in the drilledinterval. This would be the case if the formation weresufficiently competent to resist being broken up andjetted away by pump action. Thus, Core 12 (605.5-615m) cut quickly for the first 5 meters, then virtuallystopped, presumably because the barrel was full. Theremaining 4-meter interval was drilled. When the barrelwas recovered it was full, with no marked lithologicchange in the core to account for an abrupt slowing at 5meters in the cored interval; the barrel was by then full.We confirmed this by pulling the core barrel afterdrilling the interval 700.5-738.5 meters, with no attempt

47


6°00.0'N - 1136Z

5°55.0'N

5°50.0'N

0942Z26 Oct. 74

1039Z

Proposed π

Site 39-2 u Approach Track

Departure Track

1407Z31 Oct. 74

1500Z DR

Glomar Challenger track in thevicinity of Site 354

44°10'W

Figure 3. Glomar Challenger track in the vicinity of Site 354.

to core. The core barrel was full (Core 14). Thus, Cores12 to 19, at least, must be viewed as containingsediment recovered from the sum total of, or anywherewithin, the drilled-plus-cored interval.

To gain greater control on core location and toimprove the unusually low drilling rate, we dropped achisel-faced center bit and drilled the interval 738.5-814.5 meters.

It became obvious that present drilling rates wouldpreclude our reaching basement within the time left onstation. We cabled DSDP Headquarters for a day'spostponement of our scheduled 5 November crew-change rendezvous in Recife, Brazil, and attempted to

maximize core coverage and section recovery in theremaining time; Cores 15 through 18 were cut in closesuccession. We received an extension of 24 hours atabout the time Core 18 was recovered. On the basis ofan observed basement at 1.0 sec on the approach profile(Figure 4) and calculations based upon seismic veloci-ties measured onboard, we believed acoustic basementto lie below 1000 meters, and again dropped the chisel-faced center bit. After only 5 meters of penetration, weencountered a very hard formation. We pulled thecenter bit to prevent bending and sticking, and found itto contain a small (~ 1 cm diameter) chip of chert. Core19 was cut over 14 meters, of which we recovered 9.5

48


'.-I

1 IT ifill

X Y

Figure 4. Glomar Challenger approach profile, Site 354. Points X, Y, and Z refer to Figure 3.

TABLE 1Coring Summary, Site 354

Core

123456789

10111213141516171819

Total

Depth BelowSea Floor

(m)

0.0- 7.045.0- 54.592.5-102.0

140.0-149.5187.5-197.0235.0-244.5282.5-292.0339.5-349.0396.5-406.0453.5-463.0520.0-529.5605.5-615.0691.5-700.5700.5-738.5814.5-824.0833.5-543.0852.5-862.0871.5-881.0886.0-900.0

Cored(m)

7.09.59.59.59.59.59.59.59.59.59.59.59.5

38.09.59.59.59.5

14.0

211.0

Recovered(m)

2.60.19.59.53.03.35.44.67.89.59.59.59.59.53.47.84.09.58.4

119.4

Recovered(%)

37-1

26100

3235574878

100100100100

25368242

10060

56

meters of basalt. At least 2 meters of the 14 meterscored was a soft interval, indicating the possiblepresence of (unrecovered) soft sediment layers withinthe basalt. During core recovery, the bottom 1.1 metersof the core dropped through the stripped core catcherand bridged the drill pipe at 365 meters, making itnecessary to trip the pipe up this far to retrieve the pieceof basalt. The major scientific goals at this site hadalready been satisfied and the site was abandoned.

Glomar Challenger left Site 354 at 13O5Z, 31 October74, on a northerly course (Figure 3), streamed gear,turned to port, and after some current offset, passedover the beacon at 1421Z, changing course to 187°Tand holding this course at slow speed (6 knots) for 30minutes. At 1450Z, we changed course to 140°T andincreased speed to full for the steam into Recife, Brazil.

LITHOLOGY

Sedimentary Section

Sampling of the sedimentary section of the CearáRise was discontinuous. We recovered 19 cores atvarious intervals; the last core bottomed in basalt. Ninemajor lithostratigraphic units occur at this site (Figures5 and 6, and Table 2).

49


Sediment Components Core Unit Lithology Age

9 0 0 ^CO, Fragments | ^ |Dolomite

Diatom-Rads | * » * | Fe-Mn Oxides

o 10 20 30 40 50 percent

[&*&] Foraminifers

|-*- | Nannofossils

1 3 Clay |zT| Zeolite

Figure 5. Lithology, age, and sediment components, Site 354.

50


Site 354 Smear Slide Summary

% CaCO

Depth(ml Core Unit Age Lithology 0

Fe-Mn

%CaCO, %Forams % Nannos Frags. % Biosiliceous Qtz. Silt % Clay Zeolite Oxides Pyrite Dolomite Sand:Silt:Clay

Figure 6. Smear-slide summary, Site 354.

50 0 50 0 50 0 50 0

•

i

I

\

fs

\

50 0 10 0 10 0 10 0 100

sand 11 clay

i 1

1

w1

<

i

ii

Units 1 and 2

These units are calcareous muds, similar in min-eralogic and biogenic composition, and of Pleistoceneage. Both are essentially silty nannofossil muds,containing about 40% calcareous biogenous materialand over 50% terrigenous components. For the mostpart, these units average 3O%-35% nannofossils,together with lesser amounts of foraminifers andforaminifer fragments (5%-10%) and a minor amount

of diatom remains (5%). The terrigenous componentsare predominantly clays (40%), a subordinate siltcomponent (5%-10%), and limonite-hematite particlesand aggregates. Smear slides of the silt fraction showquartz, muscovite (?), and glauconite. Unidentifiedheavy minerals occur in trace amounts as fine silt.

The units differ in color and carbonate content. Unit1, approximately the first 1 meter of sediment (the topfew centimeters are washed or not representative), isyellowish-brown with occasional indistinct brown

51


Unit

1

2

3

4

Cores

1

1-2

3-6

7-11

Depth BelowSea Floor (m)

0-128 cm

1-48

48-240

240-550

TABLE 2Lithologic Summary Site 354

Thickness (m)

128 cm

47

192

310

Age

Late Pleistocene

Pleistocene

Mid-Miocene tolate Pliocene

Middle Oligoceneto early Miocene

Description

Unconsolidated, silty nanno-fossil mud (yellow-brown)

Unconsolidated, silty nanno-fossil mud (olive-gray)

Nannofossil ooze and marlynannofossil ooze (yellow-brown); with interbedded fora-miniferal oozes; bottoms invaricolored calcareous chalks

Pale blue-green, nannofossilchalk, with interbedded fora-

5

6

7

8

12

13-14

15-16

17-18

550-615

615-805

805-850

850-886

65

190

45

36

Early Oligocene

Mid to lateEocene

Early to latePaleocene

Maestrichtian

9 19 886- 8.2-

miniferal chalks in the uppersection; zeolitic, contortedlayers, and clay-pebble breccia-tion in the lower portion

Green-gray, zeolitic, diatoma-ceous chalk with pyrite common

Homogeneous, marly nannofossil chalk (blue-green); Frag-ments of anhedral carbonateare common

Light-gray, marly nannofossilchalk, dolomite rhombs common

Pale-red, well-indurated, marlycalcareous chalk; carbonatefragments, iron and manganeseoxides are common

Coarse-grained basalt; prominentveins of calcite

laminae. It is distinguished from the lower unit by itslower carbonate content (less than 20%) and itssomewhat greater iron oxide content (5%-10%), whichapparently imparts the yellowish hue. The ferruginousoxides occur as individual grains and as distinctcoatings on other material. Unit 2 is light olive-graywith occasional brown laminae. It also containsscattered black hydrotroilite blebs and slight mottling;carbonate content ranges from 25% to 35%. Thedifferent carbonate contents are not clearlydistinguishable from smear-slide examination.

Unit 1 is late Pleistocene in age and is clearlyseparated from Pleistocene Unit 2 at 128 cm in Core 1,Section 1. Only a core-catcher sample of Unit 2 wasrecovered in Core 2. On the basis of seismic evidence,we estimate the thickness of Unit 2 at 47 meters.

Unit 3This unit grades from nannofossil ooze to marly

nannofossil ooze, and is of late Pliocene to mid-Miocene age. It is pale yellowish-brown and yellowish-gray and contains an occasional slightly darker brownband. Color contacts within the unit are distinct butmoderately deformed, perhaps by drilling disturbanceof the unconsolidated material. Lighter gray bands alsooccur occasionally in the lower half of the unit.Nannofossils are predominant, averaging 50% to 90%;the percentages increase toward the bottom of the unit.Coccoliths or discoasters may be alternately dominant.

Foraminifers and foraminifer fragments usuallyconstitute 5% to 15%, but are more important in thelight gray bands, where they may constitute up to 75%and may show a graded structure. Carbonate contentsdetermined onboard range from 35% to 75%.Unidentified clays range from 10% to 30%, and a minorsilt component of subangular quartz, anhedral calcitegrains, and subhedral dolomite rhombs is also present.Blebs and occasional laminae of hydrotroilite ormanganese oxide are visible macroscopically and asdisseminated opaque grains in the smear slides. Theunifs color is probably due to the clay mineral contentand trace amounts of iron oxide, present as scatteredgrains.

The unit bottoms in a varicolored banded chalk inthe lower half of Core 6, Section 3. The layers, 1 to 5 cmthick, are brown, yellow, black, gray, and olive. Theyvary from nannofossil oozes to foraminifer oozes tomarls. The almost pure foraminifer layers of Section 3probably indicate winnowed lag deposits. Thissequence, deposited at extremely slow rates, includes abrief hiatus in the middle Miocene. Except foroccasional foraminifer layers, the only other composi-tion change is the disappearance of trace amounts ofdolomite rhombs in the banded chalks.

Unit 4The zeolitic nannofossil chalks of Unit 4 are 310

meters thick, extend from 240 to 550 meters (Cores 7-

52


11), and are late Oligocene to early Miocene in age. Theunit consists of foraminifer-nannofossil chalk, withoccasional bands of foraminifer chalk in the uppersection. Pale blue is the dominant color, except in theforaminifer chalks, which are light gray. Evidence ofbioturbation is common; the burrows are greenish-grayor brown. Nannoplankton remains constitute 10% to50% of the sediment, and foraminifers and foraminiferfragments range from 10% to 30%. In the white chalks,the foraminifer content is higher and may average 50%.Poorly preserved diatom remains and radiolarianfragments also occur in small amounts.

The clay content varies from 5% to 20%, and zeolitesare relatively abundant (5%-10%) in the lower two-thirds of the unit. Silt-sized grains of anhedral calciteare also common, and may constitute up to 20% of thecarbonate content. Occasional silt-sized quartz grainsoccur in the upper sections, along with scatteredhydrotroilite or manganese oxide grains. The fer-ruginous components of the overlying units are notablyabsent.

A distinguishing characteristic of this unit is theprevalence of Zoophycos burrows to a much greaterdegree than in most other units. Zoophycos burrows areabsent in Units 1, 2, and 3, and occur only rarely inUnits 5, 6, and 7, but they become prevalent again inUnit 8, of Late Cretaceous age.

Contorted beds are infrequent in the upper sectionsof Unit 4, but more predominant close to the base(Core 11, Sections 4, 5, and 6, see Figure 7), wherezones of clay-pebble breccia, as well as intense burrow-ing, occur. All of this suggests intraformation slump-ing, shear, and deformation of incompetent layers veryclose to the sediment-water interface.

Unit 5

Unit 5, represented by Core 12, is a zeoliticdiatomaceous chalk of early Oligocene age. Based ondrilling penetration records and seismic reflectors, theunit is about 65 meters thick and extends from 550 to615 meters.

The unit is light green-gray, similar in color andinduration to the units above and below, butdifferentiated by its significantly greater quantity ofdiatom remains (30%-40%). Nannoplankton remainsare the other major constituent, also averaging 30% to40%. Radiolarian debris (5%), sponge spicules (5%),and sporadic foraminifers make up the remainder ofthe biogenic components. The clay content varies from10% to 20%, and authigenic zeolites usually make up anadditional 10% to 15%. Silt-sized carbonate grains arenotably absent. Diatom remains and zeolite minerals inrelatively large amounts clearly distinguish this unit.

Also distinctive here are dark gray bands (1-2 cmthick) of laminated black and white material. Thesehave an overall composition similar to the surroundinggreenish-gray sediment, except for small amounts ofpyrite (Figure 8). Intensely burrowed zones arefrequent beneath these dark areas.

Unit 6

The nannofossil chalks of Unit 6 are middle to lateEocene in age, and are represented by Cores 13 and 14.

Figure 7. Soft sediment deformation in middle Oligocenezeolitic nannofossil chalks (Sample 354-11-5, 118-132cm). Core width 6.35 cm.

From the base of Unit 5 at 615 meters, the unit extendsto 805 meters, where the drilling rate changed.

This unit is homogeneous marly nannofossil chalk,with uniform mottling throughout. It is pale blue-green; some burrows are filled with light olive-graymaterial. Unit 6 is mineralogically and biologicallysimilar to Unit 4, except for the absence of zeolites anda somewhat greater clay content. It differs also inhaving far fewer Zoophycos burrows, which results in amore uniform appearance. Silt-sized fragments ofanhedral calcite constitute 20% to 40% of this unit.

Unit 7Unit 7, represented by the marly nannofossil chalks

of Cores 15 and 16, is middle to late Paleocene in age.Its thickness is estimated at 45 meters, but the upper

53


0.1mm

Figure 8. Pyrite partially replacing diatom frustule; indiatomaceous nannofossil ooze, Unit 5 (Sample 354-12-1, 50 cm).

contact at 805 meters is not well defined. The lowercontact, at 850 meters, is better estimated, both bydrilling rate data and seismic reflection; further, thecores in this portion of the hole are more closelyspaced, allowing for a more precise determination ofthe lower boundary.

The unit is marly nannofossil chalk, very light grayand moderately mottled throughout; one band of palered sediment occurs close to the top. Generally, itsmajor components are similar to the unit above.Nannofossils make up 50% to 70%, foraminifers 10% to20%, clay approximately 20%. Common in the upperportion are anhedral grains of calcite (20%-30%), alongwith minor amounts of silt-sized quartz. Dolomiterhombs occur throughout, in amounts ranging fromtraces to 5%. This unit is best defined by its gray colorand uniform appearance, and by the consistentpresence of dolomite rhombs.

Unit8Unit 8 is pale red marly calcareous chalk of Late

Cretaceous age and is the lowermost sedimentary unitat this site. It is represented by Cores 17 and 18 andextends from 850 meters to the basalt at 886 meters (36m thick).

The unit is well indurated, ferruginous, and marly,and is distinguished immediately by its pale red colorand black burrows. The biogenic components of thesechalks occur in wide ranges: foraminifers (5%-30%) andnannofossils (10%-35%). Anhedral carbonate grainsconstitute 15% to 25%. The coloring materials are iron

and manganese oxides, constituting 5% of the sediment,which occur as discrete subhedral grains andaggregates. A thin section of this chalk shows theoxides as distinct fillings in foraminifer tests (Figure 9).Clays constitute 10% to 30%. A distinguishing featureof this unit is the great number of distinct Zoophycosburrows, as well as other burrows. The dark material inthe burrows is distinguished only by its somewhathigher content of manganese-oxide.

A center-bit sample taken just above the basaltrecovered a small chip of chert. We do not knowwhether the sample represents a separate basal chertunit (maximum thickness of 5 m) or stringers of chertwhich may be in the lower parts of Unit 8.

Unit 9—BasaltIn Core 19, cut over a 14-meter interval, we

recovered 8.4 meters of basalt.

Macroscopic DescriptionThe basalt section is light gray with some yellowish

stain in the upper part; lower down it is darker gray.This difference probably reflects slightly more intenseweathering in the upper portion. The degree ofcrystallinity is high throughout, with visible platelets ofPlagioclase, 1 to 2 mm long. No obvious breaks intodifferent flows are evident anywhere in the core, sinceno surfaces chilled to glass (or formerly glass) occur. Itwould seem, then, that the entire core represents asingle thick flow or sill. The sediment/basalt contactwas not recovered, so we were unable to check for signs

0.1mmFigure 9. Concentrations of amorphous Fe-Mn oxides in

chambers of foraminifers; in marly chalk, Unit 8(Sample 354-17-3, 20 cm).

54


of thermal metamorphism of the sediment close to thecontact, as evidence of a sill rather than basement flow.

Prominent veins of calcite, scattered throughout thebasalt, reach thicknesses of 1 cm or more. Alsoscattered throughout the basalt, but especially abun-dant below the top 2 meters of the core, are milky-whiteconcentrations, generally a fraction of a millimeter, butin some cases more than 1 mm in diameter.

Microscopic DescriptionWe studied thin sections from different levels in the

core. The following describes a section from anintermediate level.

Section 39-354-19-6 Piece § 4, 31-32 cm: Doleriticbasalt, rather coarse grained, with doleritic-subophitictexture. Plates of calcic Plagioclase, 0.5 to 1.5 mm, withAn content ranging around 65% ±10%. ThesePlagioclase crystals show frequent albite and albite-carlsbad twinning and occasional zoning. Large, partlyeuhedral clinopyroxene crystals occur; C/7 angle isabout 45°-50°, in the range of augite. Olivine is absent,except in one doubtful case. Apparently an earliergeneration of clinopyroxene has been completelyaltered into microcrystalline calcite and other second-ary products which make up a groundmass. Thisgroundmass now is littered with relatively largemagnetite-ilmenite crystals. Frequently these opaquecrystals are skeletal, or acicular, in a network of parallelalignments. Scattered throughout the thin section arelarge (up to about 1 mm), generally rounded aggregatesof microcrystalline calcite. Also present are similar butgenerally smaller masses, consisting mainly ofmicrocrystalline silica (chalcedony), with other minorphases, probably zeolites and epidotes. A vein (roughly0.5-1 mm thick) containing calcite, chalcedony,magnetite, and traces of epidote, zeolite, and chlorite,crosses the thin section.

Thin sections from other levels in the basalt coreshow features similar to those of the section describedabove. One notable difference is that sections from theupper levels of the core tend to contain very little or norecognizable, relatively fresh clinopyroxene. This maymean that either (a) the processes of alteration whichresulted in destruction of the clinopyroxene andappearance of the calcitic-silicic groundmass were moreintense toward the top of the basalt core, or (b) somehorizontal layering exists in this doleritic basalt, with alower original plagioclase/pyroxene ratio. This secondinterpretation is consistent with the core being part of aslowly cooled thick flow or sill.

DiscussionThe coarse-grained, doleritic (or diabasic) nature of

the basalt cored at Site 354 suggests that it wasoriginally part of a slowly cooled thick flow or sill.There is evidence that some horizontal layering mayhave developed during slow cooling of the magma. Thepresence of a thick sill is consistent with seismicreflection data at Site 354, suggesting that the igneousrock reached by coring is not true basement but a sill.

Abundant calcitic-silica veins and segregationsthroughout the rock indicates that it underwent strong

hydrothermal alteration. This alteration may haveoccurred deuterically during slow cooling of themagma, by the action of heated sea water, or sub-sequently by the action of hydrothermal solutionscirculating in the oceanic crust.

The ferromanganoan sediment of Unit 8 is similar tothe basal ferruginous facies reported from manyprevious DSDP sites in all the major ocean basins(Boström et al., 1969; von der Borch and Rex, 1970;Boström and Fisher, 1971; Cronan, 1973). Thewidespread occurrence of this basal facies in both loca-tion and time suggests a continually active mechanismcommon to all ocean basins. Discussion in the litera-ture has focused on the origin of these metalliferoussediments and their association with active ridge areas.Boström and Peterson (1969) suggest a hydrothermalorigin, in which precipitates of mineralizing solutionswould have been derived from the mantle. Corliss(1971) also suggests a hydrothermal origin, but with theenriched solutions generated by the leaching of newlyextruded basalt where sea water, heated by the coolingrock mass, mobilizes the metals as chloride complexes.The iron-rich solutions then emerge, oxidize, andprecipitate as a ferric hydroxide floe, which settles nearthe vent or is dispersed by bottom water movement.Subsequent spreading and dilution with pelagicmaterial results in an upward gradation to normalmarine sediment. At this site the upward termination ofthe ferromanganoan material is abrupt, marked by anupper Maestrichtian-Paleocene hiatus.

The Maestrichtian to mid-Eocene sediments containsignificant quantities of carbonate fragments, fine sand-and silt-sized, subangular, with frequent small over-growths. These may have been produced by frag-mentation of benthic shelled organisms on a slope of arelatively shallow Ceará Rise. If so, they indicate slowbut active bottom circulation in the mid-water portionof the opening Atlantic basin.

The nearby Ceará Abyssal Plain (Site 142, in Hayes,Pimm, et al., 1972) accumulated turbidite and mixedpelagic clays and oozes from the Miocene to thepresent. Presumably, this records the onset of sedi-mentation at the Amazon Cone (Damuth and Kumar,1975). This event is also recorded at Site 354, wheredeposition of terrigenous silt and clay began in the lateMiocene-early Pliocene and increased in the latePliocene, so that the silts and clays dominate in Units 1and 2 (Pleistocene). The fine size of the terrigenouscomponent, as well as the somewhat later initiation,reflects the distal and elevated position of the CearáRise with respect to the main deposition area at thecontinental margin.

GEOCHEMISTRY

We analyzed 13 interstitial water samples aboardship for pH, alkalinity, salinity, Ca++, and Mg++. Thedata, presented in Table 3 and plotted in Figure 10,show a general increase in Ca++ and decrease in Mg++

with depth, and a reversal in both trends just abovebasement.

55


TABLE 3Summary of Shipboard Geochemical Data

Sample Subdepth Alkalinity Salinity Ca++ Mg++

(Interval in cm) (m) pH (meq/1) (%o) (mmoles/1) (mmoles/1)

1-1.3-1,4-5.

144-150144-150144-150

5-1, 144-1506-2, 144-1507-4, 144-1508-2, 144-1509-4, 144-150

11-5, 144-15012-5, 144-15013-5, 144-15016-4, 140-15017-1, 144-150

1.594.0

147.5189.0238.0288.5342.5402.5527.5613.0698.5839.5854.0

7.457.437.367.327.056.956.956.857.026.97

7.017.00

3.762.833.743.154.605.035.365.834.805.87

3.823.72

35.534.934.935.535.235.535.235.235.235.236.035.835.2

10.6512.4115.0711.7618.5423.9927.2831.9036.9241.6242.3552.8047.35

51.3846.0545.2649.5943.8739.5737.5244.3227.3625.5626.1024.3932.33

Colorimetric AlkalinityTitration

(mmoles/1)"

10 20

g(mmoles/1)

30 40

SUBDEPTH(m)

SALINITY(7o.)

34.0 35.0 36.0

ALKALINITY(meq/1)

3.0 4.0 5.0 6.0

Figure 10. Geochemical data of interstitial waters versus depth. Site 354.

PHYSICAL PROPERTIES

Physical properties data at Site 354 show an expectedcompaction trend, with very minor variations from unitto unit within the sequence. Because cored intervalswere often widely separated, we can draw only verygeneral distinctions with regard to lithology.

A word of caution is in order regarding the syringedensities listed in Table 4. Through oversight, noprovisions had been made for storing hard sedimentsamples until we could perform immersion or 2-minGRAPE density measurements on them. Consequently,after we encountered stiff sediments (which precludeduse of the syringe technique) in Core 6, fewmeasurements were possible until recovery of Core 12.We took a large number of water content samples,however, and made a least-squares fit of water contentversus syringe density for data from Cores 3 through 5.The determined relationship,

p (g/cc) = 2.41 - 0.02 (wt % H2O)

is remarkably good, with a correlation coefficient of0.91 and a standard error of the estimate of water con-tent on density of only 0.038. We used this equation toestimate syringe densities for the lower part of thesequence. One can assume that the equation holds forlower water contents, provided no significant changeoccurs in the grain density of the recovered material.The calcareous nature of the entire lithologic sequencepermits this assumption. Immersion and 2-minuteGRAPE densities agree quite well with the computedvalues. Still, the computed densities must be regardedwith suspicion. The relationship cited above holds forall syringe densities of calcareous sediments recoveredon Leg 39.

Physical properties data for Site 354 indicate threedistinct trends with depth. The uppermost sedimentaryunit sampled (Unit 3) is a nannofossil ooze whichgrades into chalk, and extends to a depth of 240 meters.Acoustic velocities in this interval are uniformly lessthan 1.6 km/sec, and there is little suggestion of agradient (Figure 11). Similarly, the water content is

56


TABLE 4Physical Properties Measurements, Site 354

Sample(Interval in cm)

Depth(m)

Velocity(km/sec)

Density (g/cc)S I G

WaterWt%

Porosity (%)I G

Acoustic ImpedanceS I G

3-1, 903-1, 1253-1, 1273-2, 213-2, 633-2, 973-2, 993-2, 1043-2, 1333-2, 1344-1, 304-1, 734-1, 1064-1, 1434-2, 104-2, 754-2, 794-3, 884-4,64-4, 1074-5, 404-5, 714-5, 1044-5, 1334-6, 244-6, 334-6, 434-6, 494-6, 684-6, 1214-6, 1304-0,05-2, 695-2, 1426-1, 1366-1, 1446-2, 776-3, 606-3, 846-3, 966-3, 1416-0,07-1, 1337-1, 1377-2, 1057-2, 1107-2, 1107-2, 1247-2, 1247-2, 1287-3, 977-3, 1027-4,557-4, 658-1, 388-1, 458-1, 1078-1, 1308-2,38-2, 668-2, 728-2, 769-1, 759-1, 789-2, 319-2, 439-2, 699-3, 529-3, 70

93.4093.7593.7794.2194.6394.9794.9995.0495.3395.34

140.30140.73141.06141.43141.60142.25142.29143.88144.56145.57146.40146.71147.04147.33147.74147.83147.93147.99148.18148.71148.80149.50195.69196.42240.86240.94241.77243.10243.34243.36243.91244.50286.83286.87288.05288.10288.10288.24288.24288.28289.47289.52290.55290.65344.38344.45345.07345.30345.53346.16346.22346.26398.75398.78399.81399.93400.19401.52401.70

—_

1.4951.5571.566

_1.600

_1.586

_1.5621.5831.5701.5591.542

_1.539

_1.4381.4641.616

_1.5631.5701.5741.6351.5781.590

_1.6111.6001.5561.4861.593

_1.7401.6171.6001.6091.6691.7061.6931.686

__

2.0201.9871.8021.766

__

1.8801.894

—_ •

2.004_

2.036__

1.875_

1.840__

1.928_—

1.826

1.6481.607

_1.6891.6931.688

—_

1.6581.6421.6701.6871.7541.759

_1.694

___

1.854_

1.8301.8171.8161.6031.7631.759

—1.7331.760

_1.7981.876

__

1.8921.9461.8791.8841.895

__

1.9121.912

___

1.7561.893

—_

1.9601.926

1.925__

1.918___

1.9531.909

_—

1.876_

1.879

1.866

38.3339.29

34.8635.0335.71

34.7134.7235.0737.1432.9631.03

62.8165.25

60.3660.1260.42

62.2163.1661.4960.4856.4856.18

28.40 60.06

29.61 50.51

29.1828.3528.8142.7230.2333.55

32.1530.25

30.6428.2627.06

25.4222.7726.0925.8325.28

24.4524.45

51.9452.7252.7865.4955.9456.18

57.7356.12

53.8549.19

-

48.2445.0149.0148.7248.06

47.0447.04

32.13 56.3625.41 48.18

22.13 44.1823.76 46.21

23.84 46.27

24.16 46.69

22.45 44.6024.62 47.22

26.23 49.19

49.01

49.79

2.40

2.632.652.70_ __ —

2.63

2.562.642.652.732.712.612.61

——-

3.012.98

-

_-————_

3.00

2.862.852.862.622.782.80

2.792.82

2.672.99_ __ —

3.063.113.023.143.23

—-———-

-

—3.253.25

——_—_

3.22

3.86

3.10

3.56

3.71

3.86

3.92

3.60

3.59

3.68

3.43

57


TABLE 4 - Continued


9-5, 709-5, 78

10-1, 6310-1, 6510-1, 13310-1, 13410-1, 13710-2, 3310-2, 4010-2, 8010-2. 10710-3, 8510-3, 10010-5, 310-5, 510-0, 011-1, 1511-1,7111-1, 12011-2,9611-2, 12011-3, 2011-3, 2411-4,6011-4,7411-5, 6011-5,7111-6, 111-6, 1012-1, 3912-1, 4012-1, 10412-2, 512-2, 1212-3, 12012-4, 10912-4, 12012-5, 6012-5, 6012-6, 1513-1, 3013-1,6713-1, 15013-2, 7013-3, 6013-3, 7013-4, 2013-5, 3013-5, 7313-5, 10013-6, 7513-6, 8613-6, 13013-6, 14014-1, 5014-2, 6014-3, 7014-4, 14214-5, 13014-5, 14914-6, 10714-6, 11015-1, 12415-1, 12715-2, 11015-3, 7915-3, 10516-2, 4016-2, 80

Depth(m)

404.70404.78454.13454.15454.83454.84454.37455.33455.40455.80456.07457.35458.00459.53459.55463.00520.15520.71521.20522.46522.70523.20523.24525.10525.24526.60526.71527.51527.60605.89605.90606.54607.05607.12609.70611.09611.20612.10612.10613.15691.30691.67692.50693.20694.60694.70695.70697.30697.73698.00699.25699.36699.80

• 699.90701.00702.60704.20706.42707.80707.99709.07709.10820.24820.27821.60622.79823.05835.40835.80

Velocity(km/sec)

1.882—

2.008___

2.108_

2.0832.109

_—

1.8772.068

_1.8491.8911.8461.945

—2.0091.988

_2.161

_2.170

_—

2.0412.068

—2.1382.215

_2.2042.163

_2.157

_2.0792.336

—_

2.164_

2.3792.3762.385

_2.385

_2.341

_2.5922.409

—2.2572.2402.293

_—

2.269_

2.6242.494

_2.5722.5132.464

Density (g/cc)S

1.882_

2.0011.966

__

1.991—_

1.906—

_1.998

_1.9431.993

_2.019

__

2.005_

1.949—

2.1742.029

__

2.016_

1.9341.9671.998

_1.927

_1.9301.905

_2.103

—_

2.116_

2.132_

2.095_

2.107___

2.0572.049

._2.025

—2.0972.057

_2.036

_2.012

__

2.058

I

_______________

_____—____

_________

____

2.060____

2.060____

2.1102.120

____—________—-

G

___

2.085__

. _———_———

2.057__—_________————_____

——————_—

2.238—

—__

2.250_—___—_—____———

WaterWt%

25.95_

20.0921.83

—_

20.57_—

24.7720.29

_—

20.26_

22.9220.51

_19.23——

19.92_

22.65_

11.6318.71

__

19.35_

23.3721.7520.24

_23.74

_21.5724.82

_15.08_—

14.45_

13.70_

15.51_

14.92___

17.3717.84_

18.91_

15.5617.36

—18.36__

19.63__

17.29

Porosity (%)S

48.84_

41.7343.82

—_

42.33_ •

47.40—_—

41.91—

45.1942.21

_40.66

_—

41.49_

44.84_

31.4040.06

_—

40.84—

45.7343.7641.91

_46.15

_45.9747.46

_35.64

—_

34.87_

33.91_

36.12—35.40

__

38.3938.87

—40.30

—36.0038.39

—39.64

__

41.07—_

38.33

I G

_ __ __ __ __ _

36.72

— __ —— —_ —_ __ __ —— _— —

38.39_ _

_ —

— —— —_ —_ _— —— _— __ —— —_ —_ —_ —— —_ —_ __ __ —_ __ —_ —— —

38.21— —— —_ —_ _

38.21 27.58— —— —— —_ —

35.2234.63 26.87

_ —. _ _

_ —_ _- -— —— —- -— __ —— —— _— —— —— -

Acoustic ImpedanceS

3.54—

4.02_———

4.15—

4.02———

4.13——

3.673.68

_4.06

———

4.21—

4.72—

4.14—

4.17——

4.28—

4.404.17

—4.16

—3.96

—-——

5.03—

5.07—

5.00-

4.93-——

4.96——

4.544.81

—4.67

—5.34

————-

5.07

I G

_ __ —— _— _- -— —— __ —

- —- -- —_ —— -_ —- -

3.89_ —_ —- —_ __ _

— —

- -— -_ -_ _- —— -- -— -- —— —— —_ —— —- -- —- -- —- -- —— -

— —4.91 5.34

- -- -— —— —5.47 5.835.50 5.83- -

_ —— —— -— -— —- -— -— -- -— —— -- -— —

58


TABLE 4 - Continued


16-3, 3516-3, 4016-3, 10516-4, 11316-4, 12016-5, 12516-5, 12716-6, 10316-6, 11017-1, 8717-1,10717-1, 11517-2, 1317-2, 5017-2, 14017-3, 1517-3, 1617-3, 9517-3, 12618-1, 2018-1, 8018-2, 5518-2, 6018-3, 5518-3, 6518-3, 7018-4, 5018-4, 6918-5, 3018-5, 4018-6, 4518-6, 5019-1, 4419-3, 3319-3, 13119-5, 9319-6, 7019-6, 70

Depth(m)

836.85836.90837.55839.13839.20840.75840.77842.03842.10857.87858.07858.15858.63859.00859.90860.15860.16860.95861.26871.70872.20873.55873.60875.05875.15875.20876.50876.69877.80877.90879.45879.50886.44889.33890.31892.93894.50894.50

Velocity(km/sec)

_2.6822.459

_2.439

_2.3732.227

_2.5992.620

_2.897

—2.417

_2.337

—2.3992.523

_—

2.608_

2.630—

2.582_

2.545_

2.570—

4.8075.1195.5745.5524.9824.970

Density (g/cc)S

2.060__

2.100_

2.079_

2.008________——__

2.063_

2.065_—_

2.074_

2.077—

2.189—__—_-

I G

__ __ __ __ __ _

__ __ _

_ _2.120 2.197

_ _1.960

_ _1.980 2.127

_ _1.970

_ _— __

2.100_ __ _

1.980— __ __ __ __ __ _

2.679 2.740_ _

2.739 2.7872.752 2.8122.642 2.692

-

WaterWt%

17.21__

15.26_

16.26__

19.75__

________

17.07_

16.95___

16.52______——_-

Porosity (%)S

38.21__

35.82_

37.07__

41.31

___

_—_____

38.03—

37.91_——

37.37_

37.19_

30.51__———-

I G

__ __ __ __ __ __ __ __ __ __ _

34.63 30.03_ _

44.18_ _

42.99 34.21_ _

43.58_ __ __ _— _

35.82_ __ _

42,99_ —_ —_ __ —— _— _1.25— —— —— —3.46- .

Acoustic ImpedanceS

5.52__

5.12_

4.93_

4.47_________—_

5.38_

5.43_—

5.36—

5.29—

5,63__—-—

-

I

_—_______—

5.55_——

4.794.63

_——__

5.485.48

—5.21

———

—

-

—

—

G

__________

5.76_—_ .

5.144.97

_—___——-——--—-——

Note: S = Syringe method; I = Immersion method; G = GRAPE.

slight, with a range of 30% to 40%. Absence of gradientscharacterizes the underlying unit, a foraminifer-nanno-fossil chalk which extends to 550 meters. Velocity datahere are scattered but uniform; water content rangesfrom 20% to 25%. The chalks below 550 meters cannotbe distinguished from one another because of wideseparation between cored intervals. Both acousticvelocity and scatter in the velocity data increasemarkedly downward through these units. Watercontent does not change significantly.

BIOSTRATIGRAPHIC SUMMARYThe stratigraphic sequence at this site ranges from

Holocene to Late Cretaceous (Maestrichtian).Although coring of the sequence was discontinuous, werecovered samples from all Tertiary epochs. Figure 12shows the microfossil zones that we recognized.

In Cores 1 to 16, calcareous nannofossil andplanktonic foraminifer assemblages are tropical, openmarine assemblages. Benthic foraminifer assemblagesrepresent lower bathyal to abyssal depths. But in Sam-ple 17, CC the nannofossil species Kamptnerius mag-nificus, generally found in shelf-depth sediments, occurs

in abundance, and the benthic foraminifers of Sample18, CC are larger agglutinated lituolids, large rotalids,and nodosariids. This latter assemblage lacks both theLate Cretaceous shelf forms and the unique abyssalCretaceous fauna. We propose outer shelf to slopedepths for this sample. Basalt was cored below Sample18, CC.

Preservation of fossils changes drastically down thesequence, paralleling to some degree the changes inlithology. First evidence of significant solution offoraminifers and coccoliths occurs in Cores 3 and 4, oflatest Miocene and earliest Pliocene age. A dissolutioninterval during this time seems typical of the equatorialAtlantic. Both coccoliths and foraminifers are corrodedand/or dissolved, but not overgrown. Preservationbecomes significantly worse in lower sections of Core 6,and in Core 7 of middle and early Miocene age.Coccoliths are overgrown with calcite, diversity offaunas and floras decreases, and siliceous fossilsbecome more abundant for the first time in thesequence.

A significant interval of slow sedimentation,including a minor hiatus, occurs in Core 6, which

59

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900. (

+ -H-+-H-

MARLY NANNO OOZE

TO

CHALK

FORAM-NANNO

CHALK

MARLY DIATOM

NANNO CHALK

•MARLYFORAMNANNOCHALK

240

¥+

550

615

--805MARLY

NANNO+ CHALK

2.0 2.5Velocity (km/sec)

3.0

YY

1.5 2.3 3.0 75.0 37.5 0 50.0Density (g/cc) Porosity(%)

Figure 11. Physical properties versus depth: +, x, andy represent syringe, immersion, and GRAPE values, respectively.

25.0Water Wt(%)

H+Y

2.0 3.5 5.0 6.5 8.0Acoustic Impedence

nw>>.

W


mm'— g

S18

late Hu)

G. Iryncatulinoides

G. insueta/dissimilis

JS. predislentus NPW

I BLACK-RECOVERY | |[)NCORED INTERVAL

Figure 12. Bio stratigraphic Summary,Site 354.

represents the late middle Miocene to late Miocene.Berger and von Rad (1972) noted that interruptedsedimentation occurred during the late middle to lateMiocene at six other Atlantic DSDP sites, includingSite 142 in the Ceará Abyssal Plain, and Sites 14, 17, 19,20, and 25 in the South Atlantic. These authorspostulate a period of peak carbonate dissolution, aresult of shallowing of the CCD in the late mid-Miocene, to explain the increased dissolution ofcalcareous fossils, the relative abundances of siliceousfossils, and the hiatuses at the sites mentioned above.The late mid-Miocene hiatus at Site 354 may also haveresulted from shallowing of the CCD at this time in thisarea of the Atlantic.

Below Core 7, foraminifers are poorly preserved,faunas impoverished, and apertures filled; foraminifersare sometimes barely recognizable. In core-catchersamples from Cores 13 and 17, foraminifers are absent.Episodes of increased dissolution of calcareousforaminifers are indicated by a second influx ofsiliceous fossils in Cores 11 and 12 (middle and lowerOligocene) and significant numbers of flattened fossilsin Core 14 (mid-Eocene). In the Eocene and Oligocene,preservation of the coccoliths is moderate andovergrowth is common.

A second hiatus from upper Eocene to lowerOligocene in Sample 354-12, CC may correlate with ahiatus of similar length found for this time at DSDPSite 144 on the Demerara Rise.

Fossils from the lower Paleogene and Up >erCretaceous are generally poorly preserved. A thirdhiatus spanning the Cretaceous/Tertiary boundary andthe lower Paleocene occurs between Cores 16 and 17.Below this hiatus, calcareous foraminifers are scarceand nannofossil diversity is reduced because of verypoor preservation.

Radiolarians are rare in Core 1, absent in Cores 2through 6, rare in most of Core 7, and common inSample 7, CC. Only the core-catcher samples of Cores 8through 11 contain radiolarians. The siliceous sequencerecorded in Core 12 includes common and well-preserved radiolarians; abundance and preservationdiminish rapidly in Cores 13 and 14, below which noradiolarians occur.

A few silicoflagellates, ebridians, archaeomonads,and endoskeletal dinoflagellates occur in the lower tomiddle Oligocene Core 12. According to Fenner (thisvolume), diatom remains occur only in Core 12, andbelong to the Cestodiscus pulchellus Zone of Jousé(1973).

ForaminifersWe processed and examined core-catcher samples

from the 18 cores taken at Site 354. Faunas in thesesamples range in age from Late Cretaceous to latePleistocene.

PleistoceneCores 1 and 2 contain well-preserved benthic and

planktonic foraminifer faunas of Pleistocene age. InCore 1 the fossils are somewhat broken, and fragilespecies are often corroded. The typical tropical plank-

61


tonic fauna of this sample includes Globorotalia trunca-tulinoides, Pulleniatina obliquiloculata, Globigerinoidesruber (pink and white), Globorotalia crassaformis, G.menardii, G. cultrata, G. scitula, and Globigerinabulloides; Sphaeroidinella dehiscens is notably absent.Mixed with these white fossils are gray- to black-splotched planktonic species derived from a reducinglayer higher up in the core.

The benthic association indicates deep water: Pyrgo,Osangularia, lagenids, an occasional agglutinatedforaminifer, and smooth and spiny ostracodes.

Core 2 contains a similar fauna, with the addition ofS. dehiscens, Globigerina pachyderma (R), and G. calida.Preservation is generally good, and the fragmentedforms are the more resistant species. Except for oneridged ostracode, the benthic fauna is a deep oneconsisting of Pyrgo, Laticarinina, spiny Uvigerina,lagenids, and echinoid fragments.

The section represented in Cores 1 and 2 covers theHolocene/Pleistocene boundary (the reducing layer inCore 1) and Zones N22 and N23 of the Pleistocene. Theassemblages are relatively well preserved deep oozes.

PlioceneCores 3 and 4 contain diverse assemblages of

Pliocene age, whereas Core 5 is late Miocene-earlyPliocene. Core 3 contains a moderately well preservedtropical planktonic foraminifer assemblage, includingGloborotalia tosaensis, G. multicamerata, G. miocenica,Sphaeroidinella dehiscens, Neogloboquadrina humerosa,and others. Smaller specimens are often fragmented,larger individuals sometimes corroded. In the deep-water benthic fauna are Uvigerina (spinose), Pyrgo,Osangularia, Gyroidina, an occasional echinoid, andfish teeth.

The planktonic foraminifers indicate an age of latePliocene. This sample appears to belong somewherebetween top N19 and lower N21.

Core 4 contains the first strongly dissolvedforaminifer assemblages. The resistant species, inconsequence, are dominant to a pronounced degree,and include Sphaeroidinella seminulina, S. sub-dehiscens, G. multicamerata, and G. miocenica. Morefragile forms are often fragmented, although a diversefauna containing Globoquadrina altispira, Globi-gerinoides sacculifer, G. obliquus, Globorotalia tumida,and G. margaritae can be recognized. Benthicforaminifers are diverse and common, and include Lati-carinina, Nonion, Triloculina, Pyrgo, Planulina,Gyroidina, Textularia, and various lagenids. Fish teethand spiny ostracodes, together with the benthicforaminifers, are all of deep origin.

This fauna belongs to the G. margaritae Zone, N19,of the lowermost Pliocene. Strong selective solution hasapparently altered the dominance of the planktonicfaunas and enriched the benthic forms.

Faunas in Core 5 are better preserved than in Core 4.Resistant forms do not dominate to the degree they didin Core 4, spinose and delicate forms occur, but benthicspecies are still scarce. Globorotalids are still abundant.S. seminulina, S. subdehiscens, G. menardii, G. tumida,O. universa, G. sacculifer, G. obliquus, G. altispira, G.

multicamerata, and simple G. margaritae are present.The genera Pyrgo, Globocassidulina, Uvigerina,Stilostomella {-Siphonodosaria), Bolivina, someagglutinated forms, and echinoid fragments comprisethe benthic element in these sediments.

The planktonic foraminifer population belongs toZones N17-N19 of the lowest Pliocene-topmostMiocene. Although no Globoquadrina dehiscens ispresent, dissolution of the faunas may have removedthis marker species. The fauna is tropical and open-marine, sometimes strongly dissolved.

MioceneCores 6, 7, 8, and possibly 9 contain faunas of

Miocene age. Core 6 contains a tropical fauna ofmiddle Miocene age, including: Globorotaliaperipheroronda, Orbulina universa, S. subdehiscens,Globoquadrina altispira, and Globorotalia mayeri,among others. The foraminifers are poorly preserved,often calcite-coated and recrystallized. Small and/ordelicate forms are usually corroded or fragmented.Benthic species are infrequent, but deep forms ofPullenia, Globocassidulina, Stilostomella(=Siphonodosaria), and Bolivina are present.

This planktonic fauna suggests an age of middleMiocene, Zone N9, since O. universa is present but trueGloborotalia fohsi fohsi is not.

Foraminifers from Core 7 are filled and coated withcalcite; preservation is very poor. The fauna is distinct,however, since it contains the first bullate forms (notpresent above) and globigerinids with high archedapertures (not present below). The fauna begins to lookmore "Oligocene" than "Miocene," which is typical oflower Miocene faunas. Species present includeGlobigerinatella insueta, Globoquadrina dehiscens, G.altispira, Globigerina venezuelana, Globorotaliaperipheroronda, and questionable Globorotalia(Turborotalia) kugleri. Deep benthic foraminifers arerare {Bolivina, Gyroidina), but solution-resistantsiliceous fossils are common, including radiolariansand sponge spicules.

The fauna is assigned to Zone N6, lower Miocene.The partial lithification and the abundance of siliceousmaterial indicate strong solution, carbonate loss, andconsequent relative enrichment of the siliceouscomponent.

Abundance of bullate forms, unkeeled globorotalids,and large subspherical species characterizes the lowerMiocene fauna of Core 8. Planktonic species include G.kugleri, Globorotalia {Turborotalia) opima nana,Catapsydrax dissimilis, G. dehiscens, Globigerinitamartini, s.l., and G. {T.) siakensis. Many forms aretightly coiled and apertures are small or covered withbullae. Benthic foraminifers are scarce {Nodosaria,Globocassidulina), but indicate deep water.

This fauna belongs to Zone N4, considered Mioceneby some researchers (Bolli and Premoli-Silva, 1973) andOligocene by others (Berggren and Amdurer, 1973).The abundance of bullate forms and covered and smallapertures reflects a supposed response to the lowtemperatures of the Oligocene and the earliest Miocene(Boersma and Shackleton, this volume).

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Oligocene

Cores 9-11 contain fossils of Oligocene age. Thefaunas of Core 9 strongly resemble those of Core 8,except that by Core 9 the globorotalids aresubstantially less abundant. This older fauna is verypoorly preserved, and most specimens are very small,so recognition of species is difficult. Many bullae aredissolved and apertures caked with chalk. Even thebenthic forms are corroded and fragmented. The taxaare Globoquadrina altispira, G. (T.) opima nana, G. (T.)kugleri, G. ampliapertura, and Globigerinita unicavus s.l.The deep benthic forms are very scarce (Globo-cassidulina), and one smooth ostracode is present.

If G. altispira is a down-core contaminant, then thissample belongs to Zone P22, upper Oligocene.However, the P22 index, G. angulisuturalis, is absent.

Poor preservation and scarcity of recognizable formsalso characterize the faunas from Core 10. Cassi-gerinella chipolensis, G. (T.) opima opima, G. (T.) opimanana, Globigerinita martini s.l., and Globigerina august i-umbilicata are recognizable. Deep benthic species arerare (Pullenia and Gyroidiná).

The presence of C. chipolensis, G. (T.) opima opimaand absence of G. angulisuturalis locate this fauna inZone P20, upper Oligocene.

The fauna from Core 11 is also impoverished, andcontains G. (T.) opima nana, G. martini s.l., G. unicavuss.l., G. ampliapertura, and a few G. (T.) opima opima.The deep benthic fauna contains Nodosaria,Stilostomella, Gyroidiná, Nonion(l) and spiny ostra-codes. In contrast to the calcareous fossils, siliceousfossils are common, and include sponge spicules, radio-larians, and diatom remains. Fish teeth also occur.

If G. (T.) opima opima is in place, this fauna belongsto Zone P20. If not, it may lie lower in the Oligocene,Zones PI9-20. The reappearance of abundant siliceousfossils and the particularly poor preservation of theforaminifers suggest a second cycle of significantcarbonate dissolution.

EoceneCores 12-15 contain sediments of Eocene age.

Because of extensive dissolution, only large, globular,and bullate species occur in Core 12, which gives thefauna a "high latitude" appearance. Included are G.martini s.l., Globigerinita globiformis, G. (T.) opimanana, and large globigerinids such as Globigerina(Subbotina) turgida and the G. ampliapertura group. Anoccasional rotalid (benthic) occurs.

The fauna is so reduced in species as to precludeexact age determination. It is tentatively assigned to theupper Eocene, Zones P15-P16.

Sample 13, CC contains no foraminifers. Core 14contains a dissolved and impoverished fauna ofplanktonic foraminifers. Species and individual fossilsare few and highly recrystallized; many are crushed orbroken. Recognizable species are "Globigerinita"howei, Acarinina soldadoensis, and Acarinina spp. Nobenthic species occur.

The presence of "G." howei indicates the sample maybe middle Eocene in age and tentatively assigned toZones P10-P11.

Core 15 contains forms assignable to the lowermostEocene. The planktonic fauna is impoverished, butbetter preserved than that of Core 14. All the fossils aresmall and encrusted with calcite, or corroded.Globorotalia (Morozovella) conicotruncata, G. (M.)simulatilis, G. (M.) marginodentata, G. (M.) velasco-ensis, Pseudohastigerina wilcoxensis, and Acarinina spp.are present. We found no benthic species. We assignthis assemblage to Zone P6 of the Eocene, although wefound no Globorotalia (Morozovella) subbotinae.

PaleoceneCore 16 contains fossils of middle Paleocene age.

Most planktonic forms have been dissolved, so speci-mens are not common. But a fauna of G. (Morozovella)pusilla s.l., G. (M) velascoensis, G. (M.) aequa, G.(Subbotina) triloculinoides, G. (Turborotalia) pseudo-bulloides, G. (Planorotalites) compressa, and G. (M.)angulata (?) was recovered. Benthic foraminifers arevery rare; recognizable species are Nodosaria afßnis andBolivina paleocenica. One Cretaceous globotruncanidoccurs in this sediment.

Despite intense dissolution and alteration, theseforms may be assigned to Zones P3/P4 of the middlePaleocene.

CretaceousAlthough Cores 17 and 18 both contain Cretaceous

nannofossils, only Sample 18, CC contains foramin-ifers. As a result of diagenetic processes, mostforaminifers are gone. The planktonic forms whichremain are tiny globigerinids and an occasional crushedglobotruncanid.2 The benthic fauna consists of nodo-sarids, rotalids, and giant agglutinate forms.Calcareous genera include Nodosaria, Bulimina,Pyrulina, Lagena, Dentalina, Pseudogavellinella (?), andvarious rotalids. Agglutinated genera are Ammo-baculites, Haplophragmium, Trochammina, Loxo-stomoides, and Glomospira.

No planktonic foraminifers, on which to base an age,are present.

Calcareous NannofossilsAll sediment cores recovered at this site yielded

common calcareous nannofossils in various states ofpreservation. Although time limitations did not allowus to core the whole sequence continuously, we didrecover an important part of the coccolith zones.

Pleistocene (Cores 1 and 2)The two uppermost cores contain Pleistocene sedi-

ments. In Core 1, Emiliania huxleyi implies a latePleistocene to Holocene age for the entire core (2.6 m).The assemblage is rich (tropical), but lacks the leastsolution-resistant species, such as Oolithotus antillaruma.o. Coccoliths are abundant to common and fairly wellpreserved in Core 1 and in Core 2, from which only acore-catcher sample is available. This sample's richassemblage includes common Pseudoemiliania lacunosa

2 Benthic foraminifers, however, are relatively common anddefinitely unique.

63


and Emiliania annula, as well as rare Gephyrocapsaoceanica. The overlapping of P. lacunosa and G.oceanica occurs within the upper part of the P. lacunosaZone (NN19).

Pliocene (Cores 3 and 4)Abundant and generally well preserved Pliocene

coccolith assemblages occur in Cores 3 and 4. Theyinclude a rich tropical flora, indicating the Discoastersurculus Zone (NN16) in Core 3 and the uppermost twosamples studied from Core 4. The assemblage in thesesamples includes Pseudoemiliania lacunosa, togetherwith birefringent ceratoliths (but no well-developedCeratolithus rugosus) and Discoaster tamalis, but withno typical Reticulofenestra pseudoumbilica, and isassigned to the lower part of the Discoaster surculusZone. In Sample 4-1, 120 cm, the assemblage is quitedifferent, and several species have their first or lastoccurrences in the interval between this and the samplesabove. We note the last occurrences of Ceratolithustricorniculatus and typical R. pseudoumbilica in Sample4-1, 120 cm, and the first occurrence of P. lacunosa andD. tamalis in Sample 4-1, 70 cm. D. asymmetricusoccurs in both samples, but no typical C. rugosus. Thelower sample would, according to the zonation ofMartini (1971) used elsewhere in this report, belong tothe C. tricorniculatus Zone (NN12) of Miocene-Pliocene age. Zone NN12 is defined as the intervalbetween the last occurrence of D. quinqueramus and thefirst occurrence of C. rugosus. Usually, Ctricorniculatus has its first occurrence in Zone NN 11; atSite 354, it occurs first above the last occurrence of D.quinqueramus, the marker form of the zone of thisname. The presence of C. acutus from Sample 4-1, 120cm, to the bottom of Core 4, indicates the C. acutusSubzone of Bukry (1973), which can be correlated withthe upper part of the C. tricorniculatus Zons of Martini.Thus, using both zonations, a hiatus is indicated,including three zones (NN13-15) of Martini and threesubzones of Bukry. The hiatus must lie betweenSamples 4-1, 120 cm and 4-1, 70 cm. A slight change incolor, from light gray above to yellowish-gray below,occurs in the foraminifer-nannofossil ooze at about 100cm in Section 4-1.

Dissolution has affected most Pliocene samples tosome extent. In some, many or most discoasters arebroken; single shields of Cyclococcolithina leptoporaand C. macintyrei are common, and the samples areenriched in the solution-resistant Sphenolithus abies.Samples containing more discoasters than coccolithshave been more heavily affected by dissolution thanthose in which the coccoliths are more abundant. Nosignificant overgrowth occurs.

Miocene/Pliocene BoundaryWe assume that the Miocene/Pliocene boundary

here is in the C. tricorniculatus Zone in Core 4 or justbelow, since Gartner (1973) found the first occurrenceof C. acutus only a few meters above the base of thePliocene in Sicily. Core 4 provided, together with Cores3, 5, and 6, excellent material for the study of cerato-liths, added new information to Gartner's and Bukry's

(1975) ideas about the evolution of ceratoliths, andprovided a new form, C. atlanticus (Perch-Nielsen, thisvolume).

Miocene (Cores 5 to 9)Though all of Core 5 and most of Core 6 can be

assigned to the upper Miocene D. quinqueramus Zone(NN11), Core 6, Section 3 also contains Zones NN10and NN9, and indicates a minor hiatus in the mid-Miocene, probably including part of Zone NN9, all ofZone NN8, and part of Zone NN7. Assemblages ofZones NN7, NN6(?), and NN5 occur in the bottom ofthis section, which consists of gray, yellow, olive, andbrown marly nannofossil chalk bands. Above theminor hiatus, the sediment accumulation rate wasextremely slow, and it is possible that the very shortinterval of Zone NN8—0.2 m.y.—was not sampled.

Preservation of the coccoliths changes frommoderate above the hiatus to poor below. Signs ofdissolution are present in the whole Miocene sequence,but significant overgrowth—mainly on the disco-asters—occurs only below the hiatus.

Cores 7 and 8 are of early Miocene age, and show lessdiverse assemblages than those of middle and lateMiocene age. This is probably a consequence of both aprimary lower diversity of calcareous nannoplankton inthe early Miocene and the more advanced state ofdiagenesis. Most of Core 7 belongs to the Sphenolithusheteromorphus Zone (NN5), or perhaps to theHelicopontosphaera ampliaperta Zone (NN4), althoughwe did not find the latter species. Sample 7, CC,includes S. belemnos without S. heteromorphus orTriquetrorhabdulus carinatus, and thus belongs to the S.belemnos Zone (NN3). Discoaster druggi occurs in theuppermost sample studied from Core 8, and indicatesthe zone of this name (NN2). The rest of the corebelongs to the T. carinatus Zone (NN1), as does Core 9,except for the core-catcher portion.

Oligocene/Miocene BoundaryThe Oligocene/Miocene boundary is usually placed

within Zone NN1, the T. carinatus Zone. An Oligoceneassemblage of the 5. ciperoensis Zone (NP25) occurs inthe Core 9 core-catcher sample. Since at least the upperpart of Core 9 may have been collected in the drilledinterval between Cores 8 and 9, we state only that theboundary occurs in the interval between the two cores.

Oligocene (Cores 9 to 12)We recognized all Oligocene coccolith zones (NP 25

to NP 21) at this site: 5. ciperoensis Zone (NP 25) in thecore-catcher sample of Core 9 and most of Core 10; S.distentus Zone (NP 24) in the core-catcher sample ofCore 10 and Sections 1 through 4 of Core 11; S.predistentus Zone (NP 23) in the three upper sections ofCore 12; and the Ericsonia subdisticha Zone (NP 21) inthe rest of Core 12, except the bottom of the core-catcher sample, where an upper Eocene assemblage ofthe S. pseudoradians Zone (NP 20) occurs.

Coccoliths in the Oligocene are common to abun-dant, and the preservation is moderately good to poor.Overgrowth has affected the few discoasters present

64


and often makes it almost impossible to identify thesphenoliths used for zonation. We found only a singleIsthmolithus recurvus, a species typical of the earlyOligocene and late Eocene of intermediate and highlatitudes. It has been suggested that /. recurvus does notoccur in tropical open ocean localities; it was reported,however, in lower Oligocene at nearby DSDP Site 142(Roth and Thierstein, 1972).

Eocene/ Oligocene BoundaryThe Eocene/Oligocene boundary is characterized by

the sudden disappearance, between two samples fromthe core catcher of Core 12, of Discoaster barbadiensisand D. saipanensis, which occur in the upper Eocenesample. The Oligocene sediment in Core 12 is graynannofossil chalk, the Eocene a somewhat lighter graynannofossil chalk. No physical sign of a hiatus orindicator of extremely slow sediment accumulation rateis apparent. Also, the contact seems natural rather thanartificial, as would be the case if parts of the corecatcher were inadvertently picked up at differentdepths. Although the lowermost coccolith zone of theOligocene and the uppermost zone of the Eocene arepresent, the sequence is probably incomplete, judgingfrom the rather abrupt change in the coccolith flora.

Eocene (Cores 12 to 14)Only two Eocene coccolith zones are represented at

this site: the upper Eocene S. pseudoradians Zone (NP20) and the middle Eocene Nannotetrina fulgens Zone(NP 15). The former occurs in the core-catcher sampleof Core 12 and in Core 13 (except core-catcher sample)and is characterized by scarce S. pseudoradians,Reticulofenestra umbilica, Helicopontosphaera com-pacta, and another single /. recurvus. Zone NP 15occurs in the core-catcher sample of Core 13 and inCore 14. It includes Chiasmolithus gigas, C. grandis andC. solitus, and Pseudotriquetrorhabdulus inversus;Nannotetrina sp. is uncommon. Zygrhablithus bijugatusoccurs consistently in low numbers, as do S. radiansand S. furcatolithoides. The coccolith assemblages areconsiderably more diverse in the Eocene than in theoverlying Oligocene, despite generally poorerpreservation, and thus indicate a primary higherdiversity.

Paleocene/Eocene BoundaryAlthough the Eocene/Paleocene boundary may, in

principle, be easily recognized with calcareous nanno-fossils, it is difficult to decide coccolith assemblages ofCore 15 belong. All samples from this core contain fewto common Discoaster multiradiatus, a typical upperPaleocene species that extends, however, into thelowermost Eocene. It is usually associated withfasciculiths in the upper Paleocene, and with species ofMarthasterites in the lower Eocene. No Marthasteritesor fasciculiths occur in Core 15. We assign a Paleoceneage to Core 15, and assume the Paleocene/Eoceneboundary to be between Cores 14 and 15.

Paleocene (Cores 15 and 16)Core 15 and Sections 1 to the top of 6 of Core 16

belong to the uppermost Paleocene D. multiradiatus

Zone (NP 9). In the remaining part of Section 6, Core16, the other four upper Paleocene coccolith zonesoccur. A piece of upper Maestrichtian gray marlynannofossil chalk was attached at the bottom ofSample 16, CC. At the top of Core 17, which consists ofred upper Maestrichtian nannofossil chalk, some piecesof gray nannofossil chalk occur. They include analmost monospecific assemblage of Thoracosphaeraoperculata. This species is usually common in thelowermost Paleocene all over the world and is rock-forming in the Danian of northern Europe. The piecesat the top of Core 17 probably result from downholeslumping, and so represent a part of the uncoredinterval around the Cretaceous/Tertiary boundary.

The Paleocene assemblages are only somewhat betterpreserved than those of the Eocene (less overgrowth),but not so diverse as Paleocene assemblages from shelfareas such as Egypt or Tunisia.

Cretaceous/Tertiary BoundaryWhen we studied an upper Maestrichtian sample

from the bottom of Core 16, we thought the Creta-ceous/Tertiary boundary had been cored, since the topof the core was of late Paleocene age. Subsequent studyrevealed, however, that the cut core itself was entirelyPaleocene and that the Maestrichtian rock was merely athin layer attached to the core catcher. Between Cores15 and 16, we washed nine meters and cored thefollowing nine meters (Core 16). It is thus most likelythat the core barrel was filled just below Core 15, andthat the lower part of the Fasciculithus tympaniformisZone (NP 5) and younger Paleocene sediments were, ifpresent, pushed away by the full core barrel. Before thecore was retrieved, a small amount of Maestrichtianrock from the bottom of the interval remained attachedto the core catcher. We thus do not know whether ahiatus exists at the Cretaceous/Tertiary boundary. Wedo know, however, that the lower Paleocene sediments,if present, must have been deposited at a slow rate, andthat any hiatus must have been very short, since boththe lowermost Paleocene (in the lump on top of Core17) and the upper Maestrichtian (at the bottom of Core16 and in Core 17) are present.

Late Cretaceous (Cores 16, 17, and 18)We recovered upper Maestrichtian (Nephrolithus

frequens Zone) to lower Maestrichtian sediments in thecore catcher of Core 16 and in Cores 17 and 18. Thepresence of N. frequens at this low latitude deservesspecial mention, since this species is believed to be amarker for high-latitude upper Maestrichtiansediments only. We did not find Micula mura, markerfor the upper Maestrichtian in low latitudes, but it mayoccur in the unrecovered interval. Where the twospecies occur together, M. mura occurs slightly after N.frequens. The latter occurs only in Sample 16, CC; therest of the Maestrichtian sediment belongs to theLithraphidites quadratus Zone, down to Sample 17-2, 85cm, and to the Arkhangelskiella cymbiformis Zone,down to the lowermost sediment sample abovebasement, Sample 18, CC. A. cymbiformis itself is veryuncommon, even absent in some samples, soassignment to this zone is not very certain. On the other

65


hand, we found none of the marker species of thelowermost Maestrichtian and upper Campanian, suchas Tetralithus trifidus, Eiffellithus eximius, or T.gothicus. We therefore suggest an early, but not earliest,Maestrichtian age for the lowermost sediment samplesat this site.

Coccoliths are generally rare to common and poorlypreserved. Solution-resistant coccoliths have beenaffected by overgrowth, and in many samples onlythese solution-resistant species are left. Kamptneriusmagnificus is rare to few. This species is believed to havepreferred shallow seas, since it has not yet been foundin significant numbers in true deep-sea sediments. Itspresence may thus indicate relatively shallow water atthis site during the Maestrichtian.

RadiolariaWe recovered radiolarians from the Pleistocene

(Core 1), lower Miocene (Cores 7 and 8), lowerOligocene (Cores 11 and 12), and the upper to middleEocene (Cores 13 and 14).

Traces of radiolarians occur in Core 1, but only thelarge sample of the core catcher yielded enoughspecimens to assign an age to the core. Ommatartustetrathalamus, Anthocyrtidium opirense, and Collo-sphaera tuberosa indicate that this sample is probably oflate Pleistocene age.

No radiolarians are present in Cores 2 through 6.Sample 7-1, 130-133 cm, contains a few specimens ofLychnocanoma sp. cf. L. elongata, Cornutella profunda,Siphocampe sp., and Rocella gemma. Sections 3 and 4 ofCore 7 were barren of radiolarians, except Sample 4,84-86 cm, which contains a poorly preservedassemblage of the Calocycletta costata Zone of earlyMiocene age. In Sample 7, CC, a much better preservedassemblage of this zone occurs, including D. dentata, C.cornuta, C. leptetrum, L. staurophora, D. forcipata, S.wolßi, and C. virginis.

Samples 8-1, 110-112 cm and 8-3, 104-106 cm, arebarren of radiolarians, and only a small, poorlypreserved assemblage, probably belonging to theStichocorys delmontensis Zone, occurs in Sample 8, CC.

Except for small amounts of pyritized radiolarians inthe core-catcher samples of Cores 9 and 10, Cores 9 and10 and all sections of Core 11 are barren of Radiolaria.Sample 11, CC, however, contains abundant and well-preserved radiolarians of the lower Oligocene Theo-cyrtis tuberosa Zone. The rare occurrence of Litho-cyclia crux and Dorcadospyris quadripes and thecommon occurrence of Centrobotrys gavida indicate themiddle of this zone, which is also present throughoutCore 12. Core 13 contains infrequent, poorly preservedradiolarians, probably of late Eocene age, throughoutits length. Thyrsocyrtis bromia occurs sparsely inSample 13-4, 70-72 cm and in the core-catcher sample,and a single specimen of T. tetracantha occurs inSample 13-3, 60-62 cm. These occurrences indicate theupper Eocene T. bromia Zone in this core. Radiolariansrapidly decrease in abundance in Core 14, whereinfrequent occurrences of Eusyringium lagena mayindicate a middle Miocene age for this interval. Noradiolarians occur below Core 14.

DiatomsAccording to Fenner (this volume), diatom remains

occur only in Core 12 (lower Oligocene) and belong tothe Cestodiscus pulchellus Zone of Jousé (1973). Benthicdiatom remains are rare, and this suggests deep-waterconditions and large distance from littoral regions forthis site during the early Oligocene. No distinctivedifferences in the dominance, diversity, or speciescomposition of the marine planktonic diatom fossilsare apparent in the different lithologies in Core 12(intensely burrowed dark green-brown bands;moderately burrowed diatom chalk and laminatedbands). Thus changes in deeper water circulation,rather than alteration of the surface water char-acteristics, probably are responsible for the lithologicchanges. The assemblages are markedly different fromthose of early Oligocene age described by McCollum(1975) and Hajos (personal communication to Fenner)from the Southern Ocean.

SEDIMENT ACCUMULATION RATES

Figure 13 summarizes the accumulation history atSite 354. Two intervals cored in this essentially pelagicsequence show a hiatus or a period of extremely slowaccumulation. For details of the mid-Miocene hiatus,see Figure 14; Figure 15 shows the late Paleocene to lateMaestrichtian period of slow accumulation.

Zonations in the Maestrichtian sequence are notdistinct enough at this site to allow any estimate of theaccumulation rate. Accumulation may have beencontinuous but slow (in the order of 0.2 cm/1000 yr)from the late Maestrichtian through the late Paleocene,or a short hiatus may have occurred in the earlyPaleocene and/or the latest Maestrichtian (see Figure15 and discussion under Calcareous Nannofossils.)

From the late Paleocene through the early Miocene,accumulation was continuous at a rate of about 1.5cm/1000 yr, except for a short hiatus at theEocene/Oligocene boundary. In Figure 13, thesedimentation line has been drawn through the agesindicated by the core catchers of a core, where the corebelongs to a younger zone than the core catcher. Ineach case, the recorded core depth is at the bottom ofthe interval drilled with the core barrel in place; thecore-catcher sample is most likely to come from thebottom of this interval. The core itself may have beencollected anywhere between the next higher core andthe top of the core catcher. Where the core catchersample is one or more coccolith zones older than thecore, it seems likely that it was collected well below therest of the core.

A short hiatus may have occurred at the Eo-cene/Oligocene boundary (core-catcher sample, Core12). The Oligocene sediment is greenish-gray marly,diatom-rich nannofossil chalk, the upper Eocenesediment is light gray, nannofossil chalk. A dark graylayer 3 mm thick forms the very base of the Oligocenebeds and is visible as fill in tiny burrows in the lightgray Eocene sediment. Since both the lowermost Oligo-cene and the uppermost Eocene coccolith zones arerepresented, the hiatus must have been short.

66


Site 354Ceara RiseDepth

(m) Li thMIOCENE OLIGOCENE EOCENE

50PALEOCENE

i

MAEST

1 II

Flank o f Ceara Rise

100

200

300

400

500

600

700

hsi•r• -

xM

TU

10 20 30 40 60

6 cm/1000 yrs

-J< 0.004 cm/1000 yrs

1.5 cm/1000 y r s

800

119d BASALT

Figure 13. Sediment accumulation history, Site 354.

70

67


Samples

-80 cm-5 m.y.

D. quinqueramus

NN11

D. calaavis

(D. neohamatus)

NN10D. hamatus

NN9

3*^

è8

XQI

7

CO• f i

H

6

10 11 12 13 m.y. 14

§* C. primus,'I, 90 cm<* D.

100 cm<

D. βataavis

110 cm

D. hamatus

28 cm in 7 m.y.4 cm/m.y.0.004 cm/1000 yr

120 cm

130 cm

D. ex•itis140 cm

5. hetero~morηphus

150 cm

Figure 14. Miocene sediment accumulation, Site 354, Core 6, Section 3.

A period of very slow accumulation—in the order of0.004 cm/1000 yr—is evident in Section 6-3, wherecoccolith Zones NN5 through NN11 (except NN8)occur (see Figure 14). This mid-Miocene hiatus alsooccurs at nearby DSDP Site 142 on the flank of theCeará Rise (see Figure 13). The condensed sequenceconsists of gray, green, brown, and cream-coloredbands of marly nannofossil ooze and chalk. The high,changing discoaster/coccolith ratio in this sectionindicates extensive solution in most samples studied.Above the hiatus, almost no overgrowth occurs; thissuggests that solution had taken place in the watercolumn rather than during diagenesis, when the excesscalcite would have caused overgrowth on thediscoasters. Overgrowth is common below the hiatus.

Accumulation was rapid, about 6 cm/1000 yr, duringthe remainder of the Miocene and the Pliocene andPleistocene. This high accumulation rate is a conse-quence of a touch of turbidite that this site receivedfrom the turbidites transported from the Amazon Coneto the nearby Demerara and Ceará abyssal plains. Aneven higher accumulation rate prevailed at Site 142 on

the flank of the Ceará Rise (Figure 13). A lithologicchange indicates a minor hiatus in Section 4-1, where ayellowish nannofossil ooze below gives way to a lightgray foraminifer-nannofossil ooze, containing hydro-troilite, above about 100 cm. But since the latterlithology closely resembles that of Core 3, and the samecoccolith zone, NN16, occurs in Core 3 and the upper-most 100 cm of Core 4, these top 100 cm were probably"picked up" in the core barrel well above the rest ofCore 4. So the "hiatus" in Core 4 is considered adrilling artifact.

CORRELATION OF REFLECTIONPROFILE WITH DRILLING RESULTS

The seismic profile taken on the approach to Site 354from the north is shown in Figures 4 and 16. Two air-guns of 10 in.3and 40 in.3 were working at the sametime. Recording was in two frequency bands of 80-160and 80-320 Hz. The weather was bad and acoustic noisewas great even at slow ship's speed (5 to 8 knots), so theseismic profile probably shows only the strongestreflectors. On this profile at the site location, we were

68


•samples

lateD. multiradiatus

PALEOCENE

D. no.middle

D. mohleri \ H. kleinp. F. tympaniformis

53 54 55 56 57 58 59 60 61

— 98 cm in 3 m.y.— 33 cm in m.y.

0.03 cm/1000 yr

Figure 15. Paleocene sediment accumulation, Site 354, Core 16, Section 6.

able to pick out four reflectors, at two-way travel times(DT) of about 0.07, 0.27, 0.60, and 0.90 sec (Figure 16).The distinctive feature of this profile is the almosttransparent layer between the second and thirdreflectors, which rise from the Demerara Abyssal Plainonto the Ceará Rise (Figure 4). The fourth reflector isthe acoustic basement of the Ceará Rise. Its correlationwith the rough basement of the Demerara AbyssalPlain is not clear. The intermediate third reflectorcorrelates well only from the foot of the Ceará Rise.

During the drilling of Hole 354, we attempted twiceto obtain a sonobuoy record. The sonobuoy driftednorthwest from the drilling point with the strongcurrent (about 2 knots). One air gun of 40 in3 was usedat a depth of 7 meters. Recording was in a frequencyband from 10 to 160 Hz. Unfortunately, we did nothear the radio signals from the sonobuoy at a distancebeyond 2-3 km either time. Because of the short lengthof the sonobuoy profile, we received only reflectedarrivals.

The sonobuoy record (Figure 17) shows four strongreflectors at DT about 0.07, 0.20, 0.27, and 0.90 sec.Significantly missing was a good arrival from theintermediate reflector at 0.60 sec. There was also a greatdeal of acoustic noise on the sonobuoy records, whichprevented detection of the weak reflectors.

We obtained an additional seismic record from ahydrophone streamer held in the current about 2 metersbelow sea surface and at a distance 200 meters from theship. One airgun of 40 in3 was used at a depth of 7meters. Recording was in different frequency bands: 40-320, 40-160, 40-80, 20-40, 80-160, and 160-320 Hz.There profiles (Figure 18) show the same mainreflectors as the approach profile and sonobuoy records(Figures 16 and 17): reflector 1 at 0.06 sec, reflector 4 at0.27 sec, reflector 7 at 0.62 sec, and reflector 11 at 0.91sec. In addition, there are several weak intermediatereflectors between reflector 1 and reflector 11, and alsoseveral rather strong reflections below reflector 11.

Depths of reflectors 1 through 11 are calculated byusing interval velocities which are based upon averagesof sonic velocity measured onboard ship with theHamilton Frame (Table 5). Reflectors 1, 4, 7, and 11are considered the only important reflectors at this site.

Comparison with the lithology shows that some ofthe reflectors correlate well with lithologic changes(Figure 16). Reflector 1 (the boundary between graynannofossil ooze, Pleistocene, and yellow-brownnannofossil ooze, Pliocene) divides Units 2 and 3 at 45-50 meters. The main reflector 4 probably marks thetransition zone from nannofossil ooze to nannofossilchalk between 200 and 250 meters. Although it is

69


UNIT

M•—

°r- O

7 - ^

Pleistocene

Pliocene

Miocene

Oligocene

Eocene

PaleoceneMaestr.

- S . F .

- 1 0 0

- 2 0 0

- 3 0 0

- 4 0 0

-500

-600 I

-700

- 8 0 0

- 900

o

Figure 16. Suggested correlation of Glomar Challenger approach seismic reflection profile with the lithostratigraphic sectioncored at Site 354. Numbers assigned to reflectors refer to Figure 18.

calculated to lie at the uncored depth of 210 meters, itappears in Figure 16 at 240 meters, the definedboundary between the oozes of Unit 3 and the chalks ofUnit 4. Reflector 7 corresponds to the change fromlower Oligocene nannofossil chalk to diatom-nannofossil chalk, and to a sharp drop in drilling rate ata depth of 550 meters.

Reflector 11 corresponds to the basalt layer pene-trated at a depth of 886 to 900 meters. Note that thesurface of the acoustic basement, reflector 10 (the firstclear reflector in the group of basement reflectors), isnot the basalt layer itself, but the surface of theoverlying red marls (boundary between Units 7 and 8).We may speculate on whether the reflectors below 11on the streamer profile are real, and if so, whether theymay indicate bedding within "basement," i.e., inter-layered sediment and basalt. Drilling rates definitelyquickened over a few meters while cutting Core 19.

SUMMARY AND CONCLUSIONSThe basement cored at Site 354 is a diabasic basalt,

the relative coarseness of which may indicate the slowcooling of a sill. Seismic reflections on a vertical profilecontinue below "basement," and unless they arespurious, this strengthens the case for the basalt being asill. If it is a sill, true basement would be some unknownamount older than the early Maestrichtian ageindicated by nannofossils in the oldest sediments.

The basal sediments (Unit 8) are ferruginous, clay-rich, and contain marine biogenic material. Althoughrelatively shallow-water indicators occur, the absenceof significant quantities of quartz, feldspar, and othertypically continental debris suggests a mid-oceanicorigin. Considering the relatively small size of the oceanbasin at this time, the absence of aeolian silt is some-what surprising, although a portion of the argillaceousfraction may be wind-borne.

The dominant sediments of the Ceará Rise arepelagic carbonate; a terrigenous component isabundant in the post-middle Miocene, and siliceoussediments are abundant in the Oligocene. Diatoma-ceous chalks dominate the lower Oligocene sedimentsof Unit 5. Although silica-rich, this material, because ofits age, cannot be correlated with the ubiquitousEocene chert deposits of the east equatorial Atlanticand the North Atlantic Ocean. The Si-rich sedimentsmay represent a time when this site lay beneath theequatorial area of high biological productivity. Thissuggests crustal movements of the sea floor or a widerhigh productivity zone at the sea surface at this time.Poor preservation of the carbonate fauna in Unit 5 alsoindicates a period of significant carbonate dissolution.

The entire sedimentary section on me Ceará Rise wasdeposited in a well-oxygenated environment. Theoccasional iron sulfide probably reflects local reducingmicroenvironments related to biologic activity.

70


s ••'

SEA FLOOR1

Figure 17. Sonobuoy recordobtained at Site 354.Numbers assigned to re-flectors refer to Figure 18.

Anaerobic bottom conditions existed north and southof the equatorial fracture zone area (Vema, Romanche,etc.) during the Late Cretaceous. At Sites 135-138, 140,144 (Leg 14, Hayes, Pimm et al., 1972), and 24 (Leg 4,Bader, Gerard et al., 1970), sediments are typicallyblack to gray-green muds with pyrite, overlain bydolomite and cherts. These sediments, formed underanaerobic conditions, are Aptian to Maestrichtian.Thus, strong bottom-water circulation had not yet beenestablished within or between the North and SouthAtlantic basins by Late Cretaceous time, althoughsurface-water exchange had occurred (Reyment andTait, 1972). Neither the Ceará Rise nor Site 13 on theSierra Leone Rise (Leg 3, Maxwell, Von Herzen, et al.,1970) indicates anaerobic bottom-water conditions atthat time. During Late Cretaceous spreading, bothareas were positive physiographic features, andwhatever their origin, they apparently remained abovethe level of anaerobic bottom water.

Pelagic deposition of nannofossils and foraminifersprevailed from the middle Paleocene through the earlyMiocene. The Ceará Rise is apparently a distal areawith respect to terrigenous sediment deposition. Theonly terrigenous sediments are clays whose mode oftransport may be aeolian and/or suspension. Thiscontrasts with Sites 135-137, 140, 144, and 24 in theequatorial Atlantic, where either before, during, orimmediately after anaerobic sediment accumulation,significant terrigenous influx occurred (graded sands,silts, clays, arkosic sands, "graywackes"). Thus in aLate Cretaceous-early Tertiary reconstruction, thesesites would be basinal depocenters. By contrast, the

SEA FLOOR1

U ü I INTRABASEMENTr REFLECTORS

N N

Figure 18. Vertical reflection profile obtained while on Site 354by using streamed hydrophone array (see text).

71


TABLE 5Calculated Depths to Reflecting Horizons (velocities are core averages)

Reflector

1

2

3

4

5

6

7

8

9

10

11

DT, (sec)

0.06

0.14

0.21

0.27

0.35

0.41

0.62

0.70

0.75

0.88

0.91

T, (sec)

0.08

0.07

0.06

0.08

0.06

0.21

0.08

0.05

0.13

0.03

V, (m/sec)

15601560

1575

1540

1690

1850

2000

2150

2150

2500

2550

AZ, (m)

62

55

46

68

56

210

86

54

163

38

Z,(m)

47

109

164

210

278

334

544

630

684

847

885

ApproachProfile

X

X

X

X

SonobuoyProfile

X

X

X

X

StreamerProfile

X

X

X

X

X

X

X

X

X

X

X

Ceará Rise would have been either farther from sourcesof terrigenous sediments or, more probably, physio-graphically higher.

Periods of slow sediment accumulation, or perhapshiatuses, are represented in the upper Maestrichtian-lower Paleocene and at the Eocene-Oligoceneboundary. A short hiatus occurs in the middleMiocene.

The upper Maestrichtian-Paleocene slow accumula-tion, or hiatus, is marked by small amounts of siliceousfragments and by an important contribution of benthicforaminifers, occasionally whole but usually frag-mented. This may indicate increased current activity.Hiatuses at Ceará Rise and other Leg 39 sites arediscussed in this context in the cruise synthesis chapter(Supko and Perch-Nielsen this volume).

The Ceará Rise and the similar Sierra Leone Rise inthe eastern Atlantic were probably formed at the Mid-Atlantic Ridge as voluminous outpourings of basalticmagma about 80 m.y.B.P. At that time, the rotationalpole controlling Atlantic spreading may have changed(Le Pichon and Hayes, 1971; Le Pichon and Fox, 1971;Pitman and Talwani, 1972), perhaps in response torelaxation of control over spreading direction causedby transverse ridge locking (Le Pichon and Hayes,1971). The basalt mound, after being rapidly formed,rifted in two; the Ceará Rise moved west and the SierraLeone Rise moved east, and they subsided as theymoved away from the ridge (see also Kumar andEmbley, in press). Fossils in the Maestrichtian marlsoverlying basement indicate a water depth of perhaps1000 meters. Assuming a ridge crest depth of about2600 meters, as at present, it would take about 1600meters of additional build-up to elevate the basement tothe 1000-meter contour. This is also the present relief ofthe Cearà Rise basement over the surroundingbasement. Normal spreading subsidence would result

in a depression of some 3000 meters in 80 m.y. (Sclateret al., 1971), requiring an additional 1000 meters ofsubsidence. There is some evidence, from gravity data,of compensation at depths beneath the rise (Embleyand Hayes, 1972).

The Ceará Rise has been a positive feature since itsformation, and has been a depocenter for pelagic facies,except for short periods of extreme dissolution,nondeposition, or erosion. Post-middle Miocenesediments contain significant contributions ofterrigenous material. The terrigenous silt and clayrepresent Amazon River sediment, since the AmazonRiver began draining into the Atlantic Ocean in theMiocene (Oliveira, 1956). The terrigenous componentmay have been added to the bottom sediment both asparticles of suspended sediment settling directlythrough the water column and as distal facies ofturbidites.

The origin and sediment accumulation history of theCeará and Sierra Leone rises are discussed further andcompared in the general synthesis chapter (Supko andPerch-Nielsen, this volume).

REFERENCESBader, R.G., Gerard, R.D., et al., Initial Reports of the Deep

Sea Drilling Project, Volume 4: Washington (U.S.Government Printing Office).

Berger, W.H. and von Rad, U., 1972. Cretaceous andCenozoic sediments from the Atlantic Ocean. In Hayes,D.E., Pimm, A.C, et al., Initial Reports of the Deep SeaDrilling Project, Volume 14: Washington (U.S.Government Printing Office), p. 787-954.

Berggern, W.A. and Amdurer, M., 1973. Late Paleogene(Oligocene) and Neogene planktonic foraminiferalbiostratigraphy of the Atlantic Ocean (lat. 30°N to lat.30°S): Riv. Ital. Paleontol., v. 79, p. 337-392.

Bolli, H. and Permoli-Silva, I., 1973. Oligocene to Recentplanktonic foraminifera and stratigraphy of the Leg 15

72


sites of the Caribbean Sea. In Edgar, N.T., Saunders, J.B.,et al., Initial Reports of the Deep Sea Drilling Project,Volume 15: Washington (U.S. Government PrintingOffice), p. 475-497.

Boström, K. and Fisher, DE., 1971. Volcanogenic, U, V andFe in Indian Ocean sediments: Am. Geophys. UnionTrans, v. 52, p. 245.

Boström K. and Peterson, M.N.A., 1969. The origin ofaluminum-poor ferromanganoan sediments in areas ofhigh heat flow on the East Pacific Rise: Marine Geol.,v. 7, p. 427.

Boström, K., Peterson, M.N.A., Joensuu, O., and Fischer,D.E., 1969. Aluminum-poor ferromanganoan sedimentson active oceanic ridges: J. Geophys. Res., v. 74, p. 3261.

Bukry, D., 1973. Low latitude coccolith biostratigraphiczonation. In Edgar, N.T., Saunders, J.B., et al., InitialReports of the Deep Sea Drilling Project, Volume 15:Washington (U.S. Government Printing Office), p. 685-703.

Cochran, J., 1973. Gravity and magnetic investigations in theGuiana Basin, Western Equatorial Atlantic; Bull. Geol.Soc. Am., v. 84, p. 3249-3268.

Corliss, J.B., 1971. The origin of metal-bearing submarinehydrothermal solutions: J. Geophys. Res., v. 76, p. 8128.

Cronan, D.S., 1973. Basal ferruginous sediments coredduring Leg 16, Deep Sea Drilling Project. In van Andel,T.H., Heath, G.R., et al., Initial Reports of the Deep SeaDrilling Project, Volume 16: Washington (U.S.Government Printing Office), p. 601.

Damuth, J.E. and Kumar, N., 1975. Amazon Cone;morphology, sediments, age, and growth pattern: Geol.Soc. Am. Bull. v. 86, p. 863-878.

Embley, R. and Hayes, D.E., 1972. Site survey report for Site142; In Hayes, D.E., Pimm, A.C., et al., Initial Reports ofthe Deep Sea Drilling Project, Volume 14: Washington(U.S. Government Printing Office), p. 377.

Gartner, S., 1973. Absolute chronology of the late Neogenecalcareous nannofossil succession in the equatorial Pacific:Geol. Soc. Am. Bull., v. 84, p. 2021-2034.

Gartner, S. and Bukry, D., 1975. Morphology and phylogenyof the coccolithophore family Ceratolithaceae: J. Res.,U.S. Geol. Survey, v. 3, p. 451-465.

Hayes, D.E., Pimm, A.C., et al., 1972. Initial Reports of theDeep Sea Drilling Project, Volume 14: Washington (U.S.Government Printing Office).

Jousé, A.P., 1973. Diatoms in the Oligocene-Miocenebiostratigraphic zones of the tropical areas of the PacificOcean: Beihft. Z. Naua. Hedw., v. 45, p. 333-364.

Kumar, N. and Embley, R.W., in press. Evolution and originof Ceará Rise: An aseismic rise in the western equatorialAtlantic: Geol. Soc. Am. Bull.

Le Pichon, X. and Fox, P.J., 1971. Marginal offsets, fractureszones, and the early opening of the North Atlantic: J.Geophys. Res., v. 76, p. 6294.

Le Pichon, X. and Hayes, D.E., 1971. Marginal offsets,fracture zones, and the early opening of the SouthAtlantic: J. Geophys. Res., v. 76, p. 6283.

Martini, E., 1971. Standard Tertiary and Quaternary calcare-ous nannoplankton zonation. In Farinacci, A. (Ed),Second Plank. Conf., Rome, 1970, Proc: Roma (Tecno-scienza), v. 2, p. 739-785.

Maxwell, A.E. and Von Herzen, R.P., et al., 1970. InitialReports of the Deep Sea Drilling Porject, Volume 3:Washington (U.S. Government Printing Office).

McCollum, D.W., 1975. Diatom stratigraphy of the SouthernOcean. In Hayes, D.E., Frakes, L.A., et al., Initial Reportsof the Deep Sea Drilling Project, Volume 28: Washington(U.S. Government Printing Office), p. 515-571.

Oliveira, A.I. de, 1956. Brazil. In Jenks, W.F. (Ed.), Hand-book of South American geology: Geological Society ofAmerica Mem. 65, p. 2-62.

Pitman, W. and Talwani, M., 1972. Sea floor spreading in theNorth Atlantic: Bull. Geol. Soc. Am., v. 83, p. 619-646.

Reyment, R.A. and Tait, E.A., 1972. Biostratigraphicaldating of the early history of the South Atlantic Ocean:Phil. Trans. Roy. Soc. London, ser. B, Biol. Sci., v. 264,p. 55-95.

Roth, P. and Thierstein, H., 1972. Calcareous nanno-plankton: Leg 14 of the Deep Sea Drilling Project. InHayes, D.E., Pimm, A.C., et al., Initial Reports of theDeep Sea Drilling Project, Volume 14: Washington (U.S.Government Printing Office), p. 975.

Sclater, J.G., Anderson, R.N., and Bell, M.L., 1971. Eleva-tion of ridges and evolution of the central eastern Pacific:J. Geophys. Res., v. 76, p. 7888.

Shackleton, N.J. and Kennett, J., 1974. Late Cenozoicoxygen and carbon isotopic changes in DSDP Site 284:implications for glacial history of the northern hemi-sphere and Antarctica. In Kennett, J.P., Houtz, R.E. et al.,Initial Reports of the Deep Sea Drilling Project, Volume29: Washington (U.S. Government Printing Office),p. 1179.

von der Borch, C.C. and Rex, R.W., 1970. Amorphous ironoxide precipitates in sediment cored during Leg 5, DSDP.In McManus, D.A., Burns, R.E., et al., Initial Reports ofthe Deep Sea Drilling Project, Volume 5: Washington(U.S. Government Printing Office), p. 827.

73


APPENDIX ASmear-slide Summary


APPENDIX BCarbonate and Quartz Determinations Leg 39

(See Chapter 1 for explanation.)

Section

1-11-11-21, CC1-22, CC3-13-13, CC4-14-14-24-64-64, CC5-25-25-25, CC6-26-26-36-36-36-36-36, CC7-17-17-37-47, CC8-18-28-28,CC9-29-39, CC10-210-210-310, CC11-211-411-511, CC12-112-412-512, CC12, CC

13-613-613, CC14-114-114-514, CC15-215-215-315-315, CC16-316-6

SedimentDepth (cm)

86115269325328

4525937093809575

14040141201419014770148101492518971189751904819075236722375723870238912390123907239442397528387283892856628796291753405634106341303442539895400624057545506455984567146275521615259552625529256064861011612396147561490692496997469975700257015670157706777097581626816458182181834819258369884221

CaCO3 (%)

18.2719.518.75

18.0226.6227.8946.5343.7246.1143.7859.7361.0431.8367.5953.8040.7843.4067.4968.6365.7656.5436.4067.0274.2475.3135.8675.6773.0573.4247.2880.1961.9573.6917.2751.2863.5756.7854.7853.9745.8085.0577.1164.1580.4294.9267.5457.3763.9355.0350.9159.2360.3362.4064.7067.5465.3571.5573.4055.2250.7063.2963.7962.0063.2951.3965.5843.32

Org (%)

0.220.180.360.990.250.690.120.140.850.060.100.060.090.070.750.060.090.070.750.080.030.100.060.070.061.100.360.030.070.030.090.490.100.150.150.470.090.150.240.310.180.100.310.080.060.150.450.090.180.200.400.450.100.120.150.370.120.090.090.220.060.120.210.150.390.080.10

TotalCarb (%)

2.42

3.143.454.03

5.396.39

7.28

3.918.197.21

5.308.178.997.98

4.47

8.989.104.419.44

8.89

9.727.938.952.23

8.106.91

6.725.81

9.368.019.73

11.45

7.337.77

6.317.517.697.597.89

8.22

8.916.726.317.66

7.65

6.567.955.30

Qtz (%)

15.60

15.33

11.56

13.70

14.77

5.24

5.57

7.70

7.34

5.39

5.63

4.905.51

5.69

4.72

45.09

75


APPENDIX B - Continued

Sediment TotalSection Depth (cm) CaCOo (%) Org (%) Carb (%) Qtz (%)

16, CC17-217-317, CC18-118-118-418-418, CC

842758551785630857258724087280877288772888075

53.7553.7858.0645.9153.5952.7835.8437.0253.07

0.390.150.140.880.160.210.310.270.72

6.84

7.116.376.59

4.61

7.08

76

Site 354

AGE

= •

iTO

CE

l

X.!J

°•

ZON

E

3 ~

|I

c "2 =»

—-•2£! •g

Hole

FOSSIL

CHARACTER

FOR

AM

S

1

AG

AM

.1

CG

AG

AG

RA

DS

|

RP

tor

1 S

EC

TIC

0

1

2

e 1M

ETER

:

_-

0 5—

_

' -

-_--

-

z--

Core

Catcher

Cored Interval: f

LITHOLOGY

VOID

— i — j — i — ! -

-~Λ~~^~ I ~

~.Z~.'-'.—_—

:-:.-:.—~—~.

—i—

-1— —-I— —

-I— —

1 *~.—1——(—^ (~

+— —{

+ ^ '_|

_,o

|

DE

F0R

MA

1

1

|

MPI

| L

ITH

O.S

A

59

.o-•

δ

1 S

ED

. S

TR

1

.0 m

LITHOLOGIC DESCRIPTION

58-73, MARLY-FORAMINIFERAL NANNO OOZE, moderateyellow-brown (10YR 5/4), mixed and disturbed,coarse appearance.SS 59irw riau 5% Fe Oxides

76 1 ü SiU quartz 5% DiatomsH • 10% Forams TR% Heavy mineralsP • 35% Nannos

H 9 | I 1 73-128, NANNO OOZE to MARLY NANNO OOZE, finelyI 1 laminated, moderate brown (5YR 4/4), and light

64

CC

1T

brown (5YR 5/6) laminae in a general moderateyellowish brown (10YR 5/4); bioturbation (burrows)102-114; distinction moderate brown (5YR 4/4)laminae at 119-120 and 126-128.SS 76 SS 11940TTlay 40% Clay10% Silt quartz 10% Silt10% Fe Oxides 10% Fe Oxides30% Nannos 30% Nannos5% Forams 5% Forams5% Diatoms 5% Diatoms

128-150 (Sec. 1), MARLY-NANNO OOZE, light olivegray (5Y 6/1) to pale yellow brown (10YR 6/2),some black hydrotroilite blebs, slightly darkerbrown laminae with gradation of contacts at 14 cm(Sec. 2) and 90 cm, slight mottling and burrowsthroughout.SS 64 SS CC35T"Clay 40% Clay10% Silt quartz 5% Silt quartz35% Nannos 5% Diatoms10% Forams TR% Glauconite5% Diatoms 40% Nannos5% Fe Oxides 5% ForamsBomb C03: 5JS Fe Oxides

Sec. 1, 75 cm = 14%Sec. 1, 115 cm = 18%Sec. 1, 140 cm = 27%Sec. 2, 55 cm = 33*

Si te 354 Hole Core 3 Cored Interval :92.5-102.0 m

FOSSILCHARACTER

CoreCatcher


65-CC, pale yellowish brown (10YR 6/2), MARLYNANNO OOZE, blebs of hydrotroilite throughout,thin (2 mm) laminae at 85 cm, moderate yellowishbrown (10YR 5/4), similar bands in Sec. 2delineate disturbance.

AUG Smear Slide5-15% Forams

50-60% Nannos5% Quartz silt

25-30% ClayTR% Fe OxidesTR% Dolomite

Bomb C0 3:

Sec. 1, 100 cm = 39*Sec. 2, 110 cm = 56*

Explanatory Notes in Chapter 1

Cored Interval:45.0-54.5 m

AGE

1 EA

RLY

1 P

LE

IST

OC

EN

E

ZON

E

(H22

)

Pseu

do

em

ilia

nia

lac

un

os

a

NN

19

FOSSILCHARACTER

FOR

AM

S

AG AG

RA

DS

-

SE

CT

ION

]

ME

TER

S

CoreCatcher

LITHOLOGY

DE

FOR

MA

TIO

N

|

LIT

HO

.SA

MP

LE

|

CC


CC, MARLY NANNO OOZE, light olive gray (5Y 5/2),some hydrotroilite<?) grains.SS CC 40% Nannos40% Clay 5% Forams5% silt quartz 5% Diatoms

TR% Glauconite 5% Fe OxidesBomb C03: Sec. CC = 26*

nw>>SW

Site 354

AGE

<->*j

:AR

IE

MIO

CE

LAT

ZON

E

—

o

Ul CM

ü Iu>

• "^

-oE

•g

-N1

9)

G:N

I7

Hole

FOSSILCHARACTER

[FO

RA

AM

CM

CM

CM

CM

FM

FM

AM

•£•Tim

AG

AG

AM

AM

AM

AM

AM

CM

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SS 56, 116

5% Silt quartz60% Nannos15% Forams

Bomb C03: Sec. 1, 5 cm = 49%

Sec. 2, 0-150, NANNO OOZE, generally (5Y 7/2)continues, 18-50 light gray (N8) with burrows.

MUM 5% Forams20% c l ay TR% Fe Oxides5% Silt quartz

70% Nannos

Bomb C03: Sec. 2, 90 cm = 51%

Sec. 3, NANNO OOZE, yellowish gray (5Y 7/2)and very light gray (N8) continues alternatingbands.

Sec. 4, NANNO OOZE, yellowish gray (5Y 7/2) attop to light brown (5YR 6/4) at base, somescattered hydeptroilite, moderately bioturbated.

Sec. 5, MARLY NANNO OOZE, alternating yellowishgray (5Y 7/2) and very light gray (N6), pasteand biscuit structure disturbance.SS 7930% Clay5% Silt quartz

65% Nannos

Bomb C03: Sec. 5, 66 cm = 45%

Sec. 6:0-26, moderate yellowish brown (10YR 5/4),moderate bioturbation.26-30, pale yellowish brown (10YR 6/2),moderate bioturbation.30-35, very light gray (N8), sandy.35-40, very light gray/moderate yellow brown/black (hydrotroilite), lower contact blacklaminae.40-150, alternating very light gray (N8)/yellowish gray (5Y 7/2), slight bioturbation.SS 10, 90 SS 335% Silt W S i l t

20% Clay 40% Forams70% Nannos 40% Nannos5% Forams 20% Clay

TR% Fe Oxides TR% Fe OxidesTR% Dolo rhombs

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Sec. 1:15-150, MARLY NANNO OOZE, yellowish gray(5Y 7/2) to pale yellowish brown (10YR 6/2)at base; gray and brown colors alternatethroughout, slight bioturbation throughout.57-61 cm, FORAM-NANNO OOZE, a light gray (N7)zone.

SS 60 SS 10020% Clay 15% Forams 20% Clay5% Silt quartz TR% Dolo rhombs 75% Nannos

60% Nannos 5% Forams

Bomb C03: Sec. 1, 106 cm = 34%

Sec. 2, NANNO OOZE continues from above, somelarge blebs of hydrotroilite, surrounded bywhitish material (SS 115).

SS 115SS 105, 115 5% Silt10* Clay 10% ClayTR% Silt 20% Forams5% Forams 60% Nannos

85% Nannos 5% Diatoms

136-CC, NANNO-FORAM OOZE, similar colors toabove.

SS 140, CC

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TR% Diatoms

Explanatory Notes"in Chapter 1

Cored Interval :235.0-244.5 m Cored Interval :282.5-292.0 m


127 (Sec. 1) to 30 (Sec. 2 ) , FORAM-NANNO CHALK,

very l i gh t gray (N8); 133-135, f i ne laminaewi th sharp contacts.SS 35, 14215-20% Clay 65-75% Nannos

TRX S i l t 5* Diatoms10-15J! Forams TR% Dolo rhombs

Sec. 2:30-37, NANNO CHALK, pale blue (5PB 7/2) towhite (N9), f i ne laminae incl ined •>-2O°.37-59, NANNO CHALK, pinkish gray (5YR 8 /1 ) ,some h y d r o t r o i l i t e and burrows.59-66, NANNO CHALK, s imi la r to 30-37.66-129, MARL NANNO CHALK, varigated paleyel lowish brown (10YR 6/2) to pale brown(10YR 6/3) , some burrowing and coring d i s tu r -bance.

Sec. 3, MARLY NANNO CHALK continues from abovewith add i t iona l : a l ternat ing color banding,various shades of brown-yellow brown, yellowgray, and pale o l ive (5Y, 5YR, 10Y and 10YRhues); f ine burrows throughout; generally sharpcontacts between bands.54-56 Light bluish gray (5B 7/1) bands,64-65 top two are NANNO CHALK, bottom two90-101 show graded texture with high foram134-136 content at base, h y d r o t r o i l i t e laminae.136-150, NANNO CHALK, bands of pale o l i ve (10Y6/2) and pale brown (5YR 5/2) .CC, FORAM CHALK, l i g h t greenish gray (5GY 8/1).SS 30, 55, 110 " ' SS 100, 136, CC15-20% Clay 7 M Forams

TR% S i l t N a n n°s10% Forams 10* Clay

75-65% Nannos m DiatomsTR% Fe Oxides s s 1 4 1

10% Clay90% NannosTR% Fe Oxides

CO,: Sec. 2, 107 cm = 57%Sec. 3, 91 cm = 67%


Sec. 1 , FORAM-NANNO CHALK, very pale blue(5B 8/2), moderate bioturbation.SS 13015% clay 65% Nannos20% Forams

Bomb C03: Sec. 1 , 136 cm = 72%

Sec. 2, FORAM-NANNO CHALK (s imi lar to above),burrows f i l l e d with a greenish-gray mud (5GY6/1) or moderate yellow brown mud (10YR 5/4) .95-102, zone of yellow-brown mud.116-128, FORAM CHALK, laminated white (N9),upper 2 cm bioturbated.SS 9820I~Clay5% CO, - silt

70* Nannos5% Forams

Sec. 3, FORAM-NANNO CHALK (similar to above),color grading to very light gray (N7), burrowsthroughout, but particulary at 14-17, 82-87,with yellowish-brown mud (5YR 5/4), foram sandlayers (<l cm thick) at 51, 60, 75, 94, 116,120, 132 cm.132-150, appears to have increased foram content.SS 127, 13150% Forams - Frags.35% Nannos5% Diatoms

10% ClayBomb C03: Sec. 3, 18 cm = 36% (?)

Sec. 4, FORAM CHALK (similar to Sec. 3) butwith increased foram content.0-38, contorted bedding, flow, small faults,in situ deformation, foram sand (<l cm thick)at 96, 103. 123, and 130.SS 13550% Forams - Frags.30% Nannos5% Diatoms15% Clay

CO,: Sec. 1. 137 cm = 73%J Sec. 3, 16 cm 47%


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Core 8 Cored Interval:339.5-349.0 m Hole Core 9 Cored Interval :396.5-406.0 m


Entire core - ZEOLITIC NANNO-FORAM CHALK gradingto NANNO CHALK, pale blue (5PB 7/2) and paleblue-green (5BG 7/2), alternation in color dueto burrowing, moderate bioturbation throughout.SS 58 SS 19TöTTeolite . TSTTlay50% Forams (Frags.) 5% Forams30% Nannos 75% Nannos10% Clay TR% Dolomite rhombs

5% Zeol i teTR% Pyr i te

C03: Sec. 2 , 30 cm = 51*


NANNO-FORAM CHALK, pale blue (5PB 7/2) andpale blue-green (5BG 7 /2 ) , color a l ternat ionswith burrowing, moderate b ioturbat ion through-out.SS 60T5TTlay 5% Zeol i te10% Forams65% Nannos

5% DiatomsBomb C03: Sec. 2, 63 cm = 61*

SS CC65% Nannos

5% Diatoms15% Clay15% Zeol i teTR% Dolo rhombs

*Sphenolithus ciperoensisExplanatory Notes in Chapter 1

Site 354 Hole CorelO Cored Interval :453.5-463.0 m Site 354 Hole Core 11 Cored I n t e r v a l : 5 2 0 . 0 - 5 2 9 . 5 m

FOSSILCHARACTER

CoreCatcher


NANNO-FORAM CHALK t o NANNO CHALK, pale b lue(5PB 7/2) and pale b lue-green (5BG 7 / 2 ) ,alternations in color due to burrowing orfine laminations at 24-48 (Sec. 1), moderatebioturbation throughout.Sec. 2, 0-13, intensely bioturbated, theseburrows f i l led with a grayish blue-green ooze(5BG 5/2).P_6£ TR2! Barite10% Clay jR% Dolo rhombs5% Zeolite jR% pyn•te

35% Forams40% Nannos10% DiatomsSec. 5, bioturbation decreasing.SS CC10% Zeolite25% Forams50% Nannos10% Clay

5% DiatomsTR% P y r i t eTR% Dolo rhombs

C03: Sec. 2, 98 cm = 85%


ZEOLITIC MARLY NANNO CHALK grading to ZEOLITICMARLY FORAM NANNO CHALK in lower half, paleblue-green (5BG 7/2), moderate yellowish brown(10YR 5/4) in burrows, moderate mottling through-out, some hydrotroi1ite blebs.

Sec. 4 (136) to Sec. 5 (10), NANNO FORAM OOZE,very light gray (N8) without mottling.

Zones of intense mottling:Sec. 2, 75-91, dusky yellow green (5GY 5/2).Sec. 3, 50-65.Sec. 5, 27-47.

Zones of breccia (clay-pebble):Sec. 3, 123-127, sediment fragments, 1/2-1 cmin size, angular and subrounded.Sec. 3, 145-Sec. 4, 03, clasts streaked andelongated, some suggestion of shear, clastssimilar to surrounding sediment, some clastsburrowed.Sec. 4, 7-12, small clasts (1-2 mm), zoneburrowed.

Zones of contorted bedding:Sec. 4, 28-36, broad and tight "folds".Sec. 4, 64-81, intruded zeolitic foram ooze,dusky yellow green (5GY 5/2), with flow lines,small (1/2-1.5 cm) sediment clasts of lighterpale blue-green (5BG 7/2) as in surroundingsediment.Sec. 4, 91-105, deformed bedding and shear.Sec. 5, 61-74, intensely deformed with ooze"dike", mix of competent and incompetentsediment layers.Sec. 6, 74-140, deformed with broad "folds",microfault displacing laminae of hydrotroilite.Sec. 6, 125-137, intensely deformed and burrowed.

SS 10010% Clay10% Zeolite15% Forams65% Nannos

SS 70 (Sec. 4). 145IS* Clay10% Zeolite15% Forams55% Nannos5% Diatoms

TR% Pyrite

SS 68, 70 (Sec. 6)10% Clay10% Zeolite30% Forams50% NannosTR% Pyrite

CO,: Sec. 5, 5 cm = 68%

1Sphenolithus distentusExplanatory Notes in Chapter 1

Site 354 Hole Corel2 Cored Interval:605.5-615.0 m Si te 354 Hole Core 13 Cored I n te r va l : 691.0-700.5 m

FOSSIL I ^ I UJ I . I FOSSIL I z I ^ I ICHARACTER z 2 §= t CHARACTER 2 £ S3

g o £ J— f±e LITHOLOGY | "> £ LITHOLOGIC DESCRIPTION g § 5- £ LITHOLOGY | "! £ LITHOLOGIC DESCRIPTION

£ . J ^ " ^ ZEOLITIC MARLY DIATOMACEOUS NANNO CHALK, l i g h t CM __ , V ° I D . MARLY N A N N 0 CHALK, pale blue-green (5BG 7 /2) ,- z; ~^\J^S^1 1 greenish gray (5G 8/1), moderate mottling; - Hr^P~r~LT' 1 moderate mottling throughout, some burrows- : - ,)•'_,"CZ T burrows f i l led with light olive-gray material - I - I W ' I f i l led with a light olive gray (5Y 5/2).

CM CG ° • 5 ~ £ : ; § S 5 5 2 ^ Sec 3, 63-66, darker zone of light bluish- DD ° • 5 ~ - I = I ^ ^ ^ 302 Clay1 :~-S3^S gray (5B 7 /1 ) , wi th l i gh te r laminae. CM KP ^ - ' - - . >• , 1 ,-» 10X Forams

1 n-^"^^^è * S e c " 6 > 1 3 ° - 1 5 0 • appears more indurated, ~ >Ij '. 1 '_L_! 5? DiatomsCP CM l y S Z S S greenish gray (5G 6/1). - ^ ± E ± z d i TR% Pyrite

- " ^^2-^~Z. i Zones of dark laminations: - — J *T ' 1- y - Tf^•i^=S: T Sec. 1 , 49-52, a dark gray (N3) layer with - -~- ' , ' -p-1 , . „

ty - -_- •j•rf-^a=a. f ine (•vl mm) white laminae. - _-^ j-—i_—1^ ~ ^ i ^ " i 7 T ^ = Sec. 2, 20 and 140, dark gray zones, gradational - — • • ~ •

"g CP CM CG - y i - l > • l j g I Sec. 4, 13-14, 49-50, 70-71, as above. - I~I- "|~i~|~iz! ^ ^

5 2 ~ — ' ' _ ' " ' _ ' ^ Zones of intense mottl ing: AP CM 2 ~ ~^l ' ' ' '" ~ Zr .1 .x • -y i • , Sec. 2, 55-64, a greenish gray zone (5G 6/1). I >_ , ' , ' ,<o — I- . 1 - ' i • ^ ^ n n I Sec. 3, 71-79, as above. — ~ ~* <— 10 ~ ‰ . ' " _ • ^ J 7 ' Sec. 4, 71-84, as above. ~ -~-: ' . ' i~1 *1 "^-T±^T Sec. 5, 78-89, as above. - :~ : ' , • ,-»*• ~ 3 i ^ ? : T T ^ ^ = Sec. 6, 41-51, as above. ~ " – 1 1 1

•^ o - — ^ _ • " | ò ^ * 15-10% Clay - Irp • | 1 ! n Sec. 3, 87-98, s l i g h t l y more intensely mott led.

" ^ CP CM CG ^ Z i J ~',J ~T^ ^ 3 0 * Diatoms ^ - LT_ | • | X^ . 1

•Λ — ^– j d - ^ J . f 5X Sponge spicules •S — ^ ' , ' , • i A

5 11-•{ J ^ j ^ p 1 3 ^ 10% Zeolite " : I j } . ' • ' I

g CP CM AG ^ - g ^ • J j ^ j • = 5% Sponge spicules £ 4 - -^– • . • ,-»

I ~^^^S TR- 5% Pyri te 10% Zeol i te : r l~: ' 1 ' •—- -.=j=dy=f^T 10-15% Zeol i te 35-50% Nannos ' - -~-~ 1 ' . 1_C^^^g = 30% Nannos 20-40% Diatoms £ - ~ ±T±X^ '

~ g-IJErJTTrjF 5% Sponge spicules ^ - -~- , ' , -*—; = SS TOO

^ & - ^ ~rlY•^T• I - L i- 1 T L T J y 5% Sponge spicules

o. ^ I ^ ? ^ 3 ¥ 3 ^ p i - L^-: ' . ' ' ^ Sec. 6, 33-37, 105-107, zones of grayish§ •§ -r-"SSSE^ 1 5 S - ~ i 1 1 olive-green (5GY 3/2)."Z » ~ ? ? ^ ^ S f C0 3 : Sec. 4 , 11 cm = 55% f ~ bd. ' . ' ;2 '£ 6 ~ P ^ ^ ^ T FP C« 6 : I-I-πj=JL±JL 1 C03: Sec. 6, 125 cm = 67%

Hiatus C o r e È H S S S = D S * " FP CM CP Core -~-~ • ' •~1

7 » ° FP CM Catcher -I-I- • , ' . • S8 è Catcher I~I- *-, ' . '

*LATE EOCENE *Nannotetrina fulqensExplanatory Notes in Chapter 1

Cored Interval:700.5-738.5 m Corelδ Cored Interva l :814.5-824.0 m

FOSSILCHARACTER

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MARLY-NANNO CHALK, pale blue-green

(5BG 7/2), moderate mottling throughout.

Sec. 1, 83-87, light gray (N6) zone.

SS 10036s! Clay5% Forams20% NannosTR% Diatoms4558 CO, Frags.TR% Pyrite

Sec. 4, 27 cm, Indistinct softer zone.

SS 272U%~Clay20% Forams3058 Nannos25% C0

3 Frags.

S% Diatoms

C03: Sec. 1, 106 cm - 71%

FOSSILCHARACTER

CoreCatcher


MARLY NANNO CHALK, very light gray (N7),moderate mottling.

SS 14025% Clay

10% Forams35% Nannos25% C0

3 Frags.

5% DiatomsTR% Dolo rhombs

Sec. 2, 33-35, zone of pale red (5R 6/2).

SS 34

~STTilt (Quartz)20% Clay15% Forams30% Nannos5% Diatoms20% C0

3 Frags.

5% Dolo rhombs

Sec. 3, 19 and 27 cm, zones of light brownishgray (5YR 6/1), •vl cm thick.

SS 40

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Frags.

5% Forams T R %

Diatoms

30% Nannos $% D o l o r n o m b s

Sec. 3, 136-150, broken and distorted layers,light olive gray (5Y 6/1).

C03: Sec. 2, 45 cm = 64%


Cored Interval:833.5-843.0 m Site 354 Hole Core 17 Cored Interval: 852.5-862.0 m


MARLY NANNO CHALK grading to MARLY FORAM-NANNO CHALK, medium light gray (N6) to lightgray (N7), moderate mottling throughout.SS 10015% Clays15% Forams5% C0

3 Frags.

65% NannosTR% Dolo rhombs

Sec. 6, 69-84, 101-102, 109-129, greenishgray (5G 6/1).

SS CC25% Clay25% Forams

SS 122, 147

10% Forams55% Nannos 25% Nannos5% Dolo rhombs 5% Diatoms5% C0

3 Frags. 20% C0

3 Frags.

*Bottom of CC probably TR% Dolo. rhombsfrom deeper than TR% Fe Oxidesactual core.


FERRUGENOUS MARLY NANNO CHALK grading toCALCAREOUS FERRUGENOUS MARL, pale red (5R 6/2),slight mottling.SS 12030% Clay5% Fe Oxides

20% Forams20% Nannos20% C0

3 - Debris

TR% Diatom debris '5% Dolo rhombs

C03: Sec. 2, 117 cm = 54%

Sec. 3, moderate mottling.

SS CC30% Clay10% Fe Oxides25% C0

3 - Debris

5% Forams30% NannosTR% Diatom debrisTR% Dolo rhombs

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•LATE MAESTRICHTIAN*Nephrolithus frequens

OFasci cul i thus tympaniform•Heliolithuskleinpelli

ADiscoaster mohleriΔDiscoaster nobilis

Core 18 Cored Interval:871.5-881.0 m

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MARLY CALCAREOUS CHALK, pale red (5R 6/2),moderate mottling, some burrows filled withblack material.

SS 70ISl~ClayIDX Fe Oxides25% Forams10% Nannos20% C0

3 - Debris

Grayish purple (5P 4/2), somewhat less mottling.

Dark material in burrows.

SS 14035% Clay10% Fe Oxides20X CO, - Debris20% FoPams15% Nannos

Color becoming lighter to pale red (5R 6/2)near base 40-60, 80-105, somewhat more burrowing.

CO,: Sec. 1, 130 cm = 53%Sec. 4, 128 cm = 37%


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Documents

3. SITE 354: CEARA RISE The Shipboard Scientific Party1974/10/27 · 3. SITE 354: CEARA RISE The Shipboard Scientific Party1.Rio de Janeiro . 500 km Sdb Paulo at lat. 25 S ^Plateau