3. site 367: cape verde basin

3. SITE 367: CAPE VERDE BASIN

The Shipboard Scientific Party1,2

SITE DATA

Date Occupied: 3 March 1975 (1840Z)

Date Departed: 10 March 1975 (O238Z)

Time on Site: 6 days, 7 hours, 58 minutes

Position: 12°29.2'N, 20°02.8'W

Water Depth: 4748 corrected meters (echo sounding)

Bottom Felt With Drill Pipe at: 4758 meters below rig floor

Penetration: 1153 meters subbottom

Number of Holes: 1

Number of Cores: 40

Total Length of Cored Section: 347.0 meters

Total Core Recovered: 174.3 meters

Oldest Sediment Cored:Depth subbottom: 1146 metersNature: Red argillaceous limestoneAge: Kimmeridgian/OxfordianMeasured velocity: ~3.5 km/sec

Basement:Depth subbottom: 1146 metersNature: BasaltVelocity range: 4.3 km/sec

BACKGROUND AND OBJECTIVESThe acoustic stratigraphy of the eastern basins of the

North Atlantic shows many similarities with that of theNorth American Basin. A wealth of data collectedduring the past three years, in particular by ships fromLamont-Doherty Geological Observatory (Vema andConrad), Woods Hole Oceanographic Institution

'Yves Lancelot, Lamont-Doherty Geological Observatory,Palisades, New York (Co-Chief Scientist); Eugen Seibold, Geo-logisch-Palaontologisches, Institüt und Museum der Universitat Kiel,Kiel, Germany (Co-Chief Scientist); Pavel Cepek, Bundesanstalt fürBodenforschung, Hannover, Federal Republic of Germany; WalterE. Dean, Syracuse University, Department of Geology, Syracuse,New York; Vladislav Eremeev, Institute of Geological Sciences of theAcademy of Sciences, Laboratory of Lithology Formation, Moscow,USSR; James Gardner, Deep Sea Drilling Project, Scripps Institutionof Oceanography, La Jolla, California; Lubomir F. Jansa, AtlanticGeoscience Centre, Geological Survey of Canada, Bedford Instituteof Oceanography, Dartmouth, Nova Scotia; David Johnson, WoodsHole Oceanographic Institution, Woods Hole, Massachusetts; ValeryKrasheninnikov, Geological Institute of the Academy of Sciences ofthe USSR, Moscow, USSR; Uwe Pflaumann, Geologisch-Palaontologisches, Institüt und Museum der Universitat Kiel, Kiel,Germany; J. Graham Rankin, Northeast Louisiana University,Department of Chemistry, Monroe, Louisiana; Peter Trabant, TexasA&M University, Department of Oceanography, College Station,Texas.

2David Bukry, U.S. Geological Survey, La Jolla, California(Tertiary nannofossils).

30° 25° 20° 15'

(Atlantis II), and from Bundesanstalt für Geowissen-shaften und Rohstoffe of Germany (Meteor), along thenorthwest African margin provide means to verify theextension of the major reflectors over large areas in theeastern basins. A detailed Lamont-Doherty magneticsurvey also provides good control on the inferred post-Jurassic basement isochrons and the configuration ofthe rough-quiet magnetic zone boundary (Hayes andRabinowitz, 1975). Drilling results of Legs 1, 2, and 11in the western North Atlantic allow a relatively goodcorrelation between the acoustic stratigraphy anddifferent phases of the sedimentary evolution of theNorth American Basin (Lancelot et al., 1972). Datafrom Leg 14 on the eastern side of the North Atlanticare too scarce to assess the validity of a symmetricalevolution on both sides of the Mid-Atlantic Ridge(Hayes, Pimm, et al., 1972). Prior to Leg 41 not muchwas known of the potentially symmetrical evolution ofthe eastern and western basins during the Mesozoic.Nevertheless, previous work shows that current

163

SITE 367: CAPE VERDE BASIN

circulation on the bottom was different, at least duringthe Tertiary, in the two basins. Furthermore, the pre-middle Oxfordian evolution of both basins remainedcompletely unknown. Site 367 is located in an area(Figure 1) where all these problems could beapproached at the same time.

Background

The succession of seismic reflectors observed in thedeeper parts of the North American Basin can besummarized as follows, from top to bottom: (1) seafloor; (2) Horizon A, (3) Horizon ß\ and (4) HorizonB or basement.

Drilling results of Legs 1, 2, and 11 show thatHorizon A corresponds to either middle Eocene chertlayers or a hiatus near the Cretaceous/Tertiaryboundary. A thick series of black clays of earlyCretaceous age has been recovered between Horizons Aand ß. Horizon ß is correlated with the top of a basalcarbonate sequence of Upper Jurassic to Neocomianage. Horizon B was correlated with basaltic basement(top of layer 2) at Site 100 during Leg 11. However, thislower reflector is still believed to correspond in somecases to sedimentary layers lying just above basalticbasement.

A comparable succession of reflectors can beobserved in most of the eastern basins on the easternside of the North Atlantic. Our comparison is based onthe horizontal extension of these reflectors as well as ontheir actual depth below sea level. If we assume that thedepth to oceanic basement is the same on both sides ofthe Mid-Atlantic Ridge, and if rates of accumulation inthe supposedly pelagic section of the sedimentarycolumn is considered to be approximately the same inthe eastern and western basins, then the reflectors couldcorrespond to the same age and lithologic boundarieson both sides.

Sites drilled during Leg 11, and particularly Site 105,were located as close to the continental margin aspossible where total sediment thicknesses were stillcompatible with the drilling capabilities of GlomarChallenger. Site 105, at the foot of the continental rise,bottomed in basalt overlain by Oxfordian sediments.No site has been found in the North American Basinwhere older sediments, hence closer to the continentalmargin, could be reached because of the presence of athick prism of Tertiary hemipelagic sediments makingup most of the continental rise.

On the eastern side of the North Atlantic, however,the Tertiary continental rise appears much thinner andit is possible to find areas where sediments older thanmiddle Oxfordian could eventually be reached. SeveralLamont-Doherty seismic reflection profiles show thatwhen entering the magnetic quiet zone from the easttoward Africa the basement (top of layer 2) graduallydeepens and disappears beneath a thickeningsedimentary section. Some unpublished data from oilcompanies show the basement to be relatively smoothand at an average depth of 2 to 3 km below the sea floorin the Cape Verde Basin. A set of reflectors is generallyvisible within the sedimentary section. In severalregions the lowermost of these reflectors, reflector C,

abuts the basement around the rough-quiet boundaryof the magnetic anomaly profiles (Figure 2). Thatboundary was found to be approximately middleOxfordian in age at Site 105 (Leg 11). Therefore,reflector C was believed to correspond with the top of apre-middle Oxfordian sedimentary section.

Site 367 is located in the Cape Verde Basin, in an areawhere reflector C lies exceptionally close to the seafloor (less than 1.1 sec) (Figure 2). The overlyingreflectors can be correlated from profile to profile overthe entire Cape Verde and Canary basins.

The site is located on the lower continental rise in theCape Verde Basin. The rise appears dissected by deep-sea channels, as shown by both the PDR and seismicprofiles recorded during the approach to the site. Themost important of these channels belongs to the CayarCanyon that cuts deeply into the continental slope justnorth of Dakar and then is deflected toward the southslightly east of the Cape Verde islands. Several smallerchannels can be seen south of Dakar near the base ofthe slope at the mouth of canyon and slope incisions.

ObjectivesThe two major objectives of Site 367 were to

determine the nature and age of reflector C and tocompare the sedimentary evolution of the Cape VerdeBasin with that of the North American Basin.

Jurassic EvolutionUntil now only the post-Oxfordian history of the

Atlantic has been investigated (mainly in the westernNorth Atlantic). It shows a classical example ofevolution of an oceanic basin developing between tworifted continental margins. It is characterized bycontinuous subsidence leading to successive depositionof carbonates and then clays. The middle Oxfordian onthe continental margins surrounding the NorthAtlantic shows an abrupt transgression overcontinental and lagoonal facies (Haha Basin inMorocco, subsurface data in Nova Scotia). Thattransgression marks the onset of truly open marineconditions and it shows the first abrupt invasion ofammonite faunas with Tethyan affinities all the way tocentral Mexico, as recognized already by C. Burckhardt(1906, 1912, 1919). Our objective at Site 367 was todetermine the nature of the sediments underlying theOxfordian sediments in the deep basin in order tounderstand if in deep water, that time also marks anabrupt facies change. If we assume that the sedimentscorresponding with reflector C could be argillaceouslimestones of the same Oxfordian-Kimmeridgian"Ammonitico Rosso" facies as in the North AmericanBasin, then it would be extremely interesting to knowwhether the underlying sediments are of a comparableTethyan facies. If they are, a communication with theTethys would have been restricted only to the deep partof the basin because it is not observed on the margins.If the pre-Oxfordian layers display different facies, thenit would indicate that the early Atlantic was entirelyseparated from the Tethys prior to the Oxfordian. Inthat latter case, the sediments could reflect a restrictedenvironment, possibly with carbonates, or a massive

164

Figure 1. General location of Site 36 7 in the Cape Verde Basin. Bathymetry from Jacobi and Hayes (in preparation); Magnetic Quiet Zone boundary from Hayesand Rabinowitz (1975).

ONON

Figure 2a. Lamont-Doherty Geological Observatory Vema 29 seismic profile from the Cape Verde Basin (see location on Figure 1).

20 24 0.0i i I i I i I i 1 i

{031° 166° |30i°j25δ! 265"• I J T20-* TZ I 4 JAN

Figure 2b. Lamont-Doherty Geological Observatory Vema 31 seismic profile from the Cape Verde Basin (see location on Figure 1).

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accumulation of terrigenous deposits resulting from amajor pre-Oxfordian regression in the young Atlantic.

Subsequent Evolution

So far the comparison between the North AmericanBasin and the eastern basins is based almost exclusivelyon geophysical data. A Neocomian succession verysimilar to Leg 11 profiles was described by Stahlecker(1934) from the island of Maio, Cape Verde islands.Leg 14 results show that there is good reason to believethat Horizons A and ß might indeed be of the same ageand nature on both sides of the Atlantic. These data aretoo scarce, however, to establish a good comparisonbetween the two basins. It appeared essential todetermine if the history of the North American Basin isonly of regional significance or if it corresponds to amore generalized scheme on which possible regionaldifferences could be overprinted. We can alreadypredict from Leg 14 results and from geophysical datathat the Tertiary evolution must be somewhat differenton both sides of the ocean because the massiveterrigenous phase observed in the North AmericanBasin during the post-middle Miocene times (related tothe Western Boundary bottom current) does not havean equivalent in the eastern basins where carbonatesappear more abundant at that time (less diluted?). TheMesozoic history of the eastern basins is very poorlyknown and it would be particularly interesting to verifythe presence and extension of thick black shale depositsof Early Cretaceous age in the eastern North Atlantic.Periods of restricted bottom circulation during theAptian-Cenomanian times have been sugp~sted for theSouth Atlantic and the possible occurrence of suchconditions over the entire deep North Atlantic at thesame time warranted more investigation. The sameremarks apply to the Paleogene and Neogene evolu-tion. Owing to the relatively deep water location of Site367 (~4600 m), it was expected that preservation of themicrofossils in the corresponding layers will be ratherpoor. This younger part of the record would be moreeasily investigated at Site 368 on the Cape Verde Risewhere the water depth is only about 3300 meters andwhere carbonate deposits were expected. However, thedeep location of Site 367 is more favorable for the studyof terrigenous deposits possibly derived from thenearby African continental margin. In that respect,such terrigenous "events" might be related to the trans-gression and regression cycles observed on the margin.

STRATEGYSite 367 is located at the base of the continental rise,

in the Cape Verde Basin, in 4748 meters of water. TheLamont-Doherty seismic profile (Figure 2) from whichthe site was selected (profile Vema 29) shows a firstprominent reflector at 0.05 sec below the sea floor. Thisreflector is tentatively correlated with the assumedOligocene reflector D2 observed on the African margin,the Cape Verde Rise, and the Canary Basin. It couldcorrespond to the widespread Oligocene hiatusreported from many sites drilled in the South andNorth Atlantic. Below that reflector, at 0.38 sec and0.71 sec, respectively, lie reflectors believed to corre-

spond with Horizon A and Horizon ß. Reflector C isassumed to be the lowermost reflector (at 1.06 sec) thatrises toward Horizon ß at the site location. Basementwas not clearly visible on the Lamont-Doherty profile,but a post-cruise survey run by the Valdivia (Cruise 10-1975) shows that the basement lies very close to and justbeneath reflector C (Figure 3). Because of the sedimentthickness, reflector C is only visible in a verydiscontinuous manner in most of the Cape Verde andCanary basins.

Our drilling strategy called for spot coring of most ofthe upper section above Horizon ß, then very closelyspaced to continuous coring in the lower part. Ourpenetration was to be limited only by the conditions ofboth the drill bit and the hole. In the spot-cored section,we would attempt to core all the major reflectors.

OPERATIONSSite 367 was approached from the south-southwest

on a course following the Lamont-Doherty Vema 29reference profile. We decided to make the first passover the area at slow speed (~5 knots) in order to selectthe most suitable site, and then to come back over theselected target and drop the beacon. After retrieving theseismic and magnetic gear, a second Williamson turnbrought the ship back over the beacon (Figure 4). TheGlomar Challenger seismic profile recorded at slowspeed on a 320° course (Figure 5) is very comparable tothe Vema 29 profile so that the site was easily selected.An ORE 16-kHz double-life beacon was dropped at1624 hours on 3 March and, after retrieving the gear, at1740 hours the ship was locked on site at 12°29.2'N and20°02.8'W. The PDR water depth (from sea level) wasrecorded as 4748 meters corrected. The site location isalmost exactly the same as the proposed site on theVema 29 reference profile (see Figure 2).

The drill pipe was assembled as soon as the ship waspositioned over the beacon. The bottom was felt by thedriller at 0335 hours on 4 March when the bit was at4758 meters below the rig floor. That depth coincidesexactly with the water depth (from sea level) recordedby the PDR and the depth of 4748 meters is consideredthe official one for Site 367. Two cores were obtainedjust below the sea floor and then intermittent coringwas performed until the first cherts were encountered at331 meters subbottom (see Table 1). Cherty layers werecored continuously and after Core 14, at 388 meters,intermittent coring was resumed. Limestones wereencountered at 891 meters, after having cored anddrilled through a section consisting mostly of clay, andcoring became more closely spaced. The coringoperation slowed in very hard, partly silicifiedlimestones slightly below 1000 meters, and it was foundthat continuous coring would bring the best results interms of rapid penetration. It was observed whilecutting Core 33 that the rate of penetration was slowingdown drastically after coring about 5 meters, so fromthere on the technique consisted of cutting a core untilthe penetration became almost nil and retrieving thecore barrel at that time without attempting to cut a full-length core. This technique was designed to overcomethe possibility of having hard pieces of rock jammed in

168


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169


0305 I/Sto210rpm

0138 U/Won 134°, 160 rpm0217 passed beacon 800 ft. abeam to STBD.

1624 Dropped Beacon SITE 367

0204 dropped Sonobuoy

1446 C/C to 318°

1334 R/Sto 180 rpm

1336 C/C to 314

1555 C/C to 320°

1512 S/N 144

1418 S/N 143

Figure 4. Track chart for the approach and departure o/Glomar Challenger from Site 367(solid line). Dashed line is Vema 29 track.

the core catcher, preventing any further recovery insidethe core barrel. Penetration was nevertheless extremelyslow and from Core 33 down, the time spent cuttingeach core varied from just over 2 hours to more than4.5 hours. Basalt was encountered in Core 38 at 1146meters and the penetration rate decreased abruptlywhen cutting the next two cores. While cutting Core 40the torque increased abruptly and eventually rotationbecame impossible. The drill string would rotate onlywhen the bit was lifted from the bottom of the hole.After several unsuccessful attempts at rotating the drillstring, it was decided to pull out of the hole after havingreached a total penetration of 1153 meters.

LITHOLOGYWe subdivided the section in the Cape Verde Basin

into seven lithologic units (Table 2), based oncomposition and color.

Unit 1—Nannofossil Marl Interbedded With QuartzSand (Cores 1 through 7)

This unit is composed of foraminifer nannofossilmarl which alternates with quartz sand and rareforaminifer nannofossil ooze. The marls are moderateto dark yellowish brown (10YR5/2 to 10YR4/1) and inCore 2, dark gray (N3) and have CaCCh values around40%. The sand and silty clay are dark greenish gray(5GY3/1) and various shades of yellowish brown(10YR4/4). Beds up to 1 meter thick of highlydisturbed fine- to coarse-grained quartz sand occur inCores 3, 4, and 5. The major sediment components areabundant nannofossils, rare to common foraminifers,radiolarians, and rare diatoms, sponge spicules, and

fish debris. The terrigenous components are clay,abundant to rare quartz, rare to common feldspar, andheavy minerals (zircon, titanite, rutile, and leucoxene).Mica, glauconite, and pyrite are very rare andmanganese(?) flakes occur occasionally. Thin-sectionexaminations also show rare euhedral dolomiterhombs. Intense drilling disturbance of this unitprecludes any detailed description of sedimentarystructures and contacts.

Core 6 contains nannofossil marl interbedded withstiff yellowish brown (10YR4/4) silty clay which gradesdownward to greenish gray silty clay (5YR/2) in Core7. The silty clay is characterized by a lack of biogeniccarbonate, common quartz, silt, and clay. Fineparticles, especially abundant in Core 7, may bepalygorskite, identified in sediments of a similar age atSite 140 (von Rad and Rosch, 1972).

Unit 2

Subunit 2a—Diatom-bearing Radiolarian Clay (Core 8)

This subunit has alternating greenish gray (5GY6/1)and black (Nl), diatom-bearing radiolarian clay. Theblack clay layers are about 10 cm thick and occur aboutevery 30 cm. They always have a sharp lower boundary,and either a sharp or a gradational upper boundary.The black clay is rarely bioturbated, but the greenishgray clay has frequent Zoophycos and sporadicChondrites. The sediment is stiff to semilithified.Radiolarians are abundant, diatoms are common, andsponge spicules, nannofossils, and fish debris are rare.The nonbiogenic components are abundant clay, rarequartz grains, and heavy minerals and, in the blackclay, traces of iron monosulfide(?).

170


1500Z

θ£ £5j£ 3 MAR.'75

Figure 5. Seismic profile section approaching and leaving Site 367.

0400Z

11 MAR.'75

0600Z

Subunit 2b—Zeolitic Clay With Chert andPorcellanite (Cores 9 through 14)

This subunit is a zeolitic clay with chert nodules andporcellanite. The clay is stiff, dark greenish gray(5GY4/1) to dark yellowish green (5GY5/2)alternating with black (Nl) clay. The black clay bedsare about 10 cm thick and both contacts are usuallysharp; they are less abundant than in Subunit 2a.

The greenish gray clay beds are finely laminated andburrowed. They are composed of abundant clay,common to abundant clinoptilolite. and traces of heavyminerals.

The composition of the black clay beds is similar tothat of the greenish clay beds but with the addition ofrare radiolarians, nannofossils, foraminifers, fishremains, chlorite, and glauconite. Iron oxide (?)micronodules are common. Several fine-sand laminae,composed of subangular well-sorted quartz grains,occur in Core 14, Sections 2 and 3. The lower boundaryof the unit is placed above the base of Core 14.

Unit 3—Multicolored Silty Clay (Cores 14, CCthrough 17)

This unit consists predominantly of grayish blue-green (5BG5/2) and reddish brown (10R3/4) silty clay,separated by sharp boundaries. The sediment hasmottled zones, faint horizontal laminations, and isslightly bioturbated. Thin laminae of clayey sand andone porcellanite bed occur in Core 15. Quartzpredominates in the upper part of the unit but decreaseswith depth. The quartz grains are subangular andcommonly contain sagenite (rutile needles). Ironoxides, zeolites, feldspars (plagioclase and orthoclase),and heavy minerals (titanite, rutile, and pyrite) are rare.Chlorite, euhedral carbonate crystals, radiolarians, andfish debris occur occasionally. The grayish blue-green

(5BG5/2) clay in Core 17 contains thin interbeds ofblack (Nl) shale, indicating a gradational boundarybetween Units 3 and 4.

Unit 4

Subunit 4a—Black Shale (Cores 18 through 23)

This subunit is a black, carbonaceous shale, whichburns when ignited. The content of organic carbon inthis shale varies from 8% to 28%. Plant fragments andwell-preserved fish debris occur on bedding planes ofthe shale (Figure 6). Thin laminae of quartz silt occur inthe lower part of the black shale sequence (Core 18).The laminae in Core 19 are light gray and composed ofa clayey foraminifer sand. These have sharp lowercontacts and gradational upper contacts. The laminaein Cores 20 through 23 are light green and olive-grayand are composed of clayey nannofossil chalk,foraminifers, nannofossil marl, and nannofossil-bearing clay. Analyses of Sample 21, CC show abun-dant ankerite and calcite. The black shale becomesmore calcareous, finely laminated, and burrowed withdepth. The CaCCfe content measured in one of thelaminae was 34% (carbonate bomb analysis). Withinthis subunit, clay is dominant to abundant, quartz israre but becomes more common in the lower part.Organic debris and palynomorphs are frequent. Pyriteand heavy minerals (rutile, titanite, and tourmaline) arerare. Clinoptilolite occurs in the upper part of thesubunit. Foraminifers and nannofossils are rare tocommon throughout. Bioturbation is very rare and wasobserved only in dark grayish green laminae.

Subunit 4b—Variegated Claystone (Core 24)

This subunit is a bioturbated, dark reddish brown(10R3/4), dark greenish gray (5G4/1), and dark gray(N3) claystone highly disturbed by drilling. It contains

171


TABLE 1Coring Summary For Site 367

Core

1234567891011

n13141516171819202122232425262728293031323334353637383940

Total

Date(March 1975)

4444444455555556666666777777888899999101010

Time

0437055307380856111214351620214902070422062408441120165521260211050407221232143818002241032808351228163220202355044313001800234303261006161320022358034209201413

Depth BelowDrill Floor

(m)

4758.0-4766.04766.0-4775.54812.0-4821.54821.5-4831.04908.5-4918.04994.0-5003.55003.5-5013.05060.5-5070.05089.0-5098.55098.5-5108.05108.0-5117.55117.5-5127.05127.0-5136.55136.5-5146.05231.5-5241.05298.0-5307.55374.0-5383.55394.0-5402.55402.5-5412.05442.5-5450.05450.0-5459.55478.5-5488.05535.5-5545.05592.5-5602.05649.5-5659.05668.5-5678.05607.0-5706.55725.5-5735.05754.0-5763.55782.5-5792.05811.0-5820.55839.5-5849.05863.5-5869.05869.0-5877.55877.5-5885.55885.5-5893.05893.0-5900.05900.0-5906.05906.0-5909.05909.0-5911.0

Depth BelowSea Floor(m)

0.0-8.08.0-17.5

54.0-63.563.5-73.0150.5-160.0236.0-245.5245.5-255.0302.5-312.0331.0-340.5340.5-350.0350.0-359.5359.5-369.0369.0-378.5378.5-388.0473.5-483.0540.0-549.5616.0-625.5636.0-644.5644.5-654.0684.5-692.0692.0-701.5720.5-730.0777.5-787.0834.5-844.0891.5-901.0910.5-920.0939.0-948.5967.5-977.0996.0-1005.5

1024.5-1034.01053.0-1062.51081.5-1091.01105.5-1111.01111.0-1119.51119.5-1127.51127.5-1135.01135.0-1142.01142.0-1148.01148.0-1151.01151.0-1153.0

Cored(m)

8.09.59.59.59.59.59.59.59.59.59.59.59.59.59.59.59.58.59.57.59.59.59.59.59.59.59.59.59.59.59.59.55.58.58.07.57.06.03.02.0

347.0

Recovered(m)

7.99.03.27.71.01.10.557.31.10.40.81.74.05.256.38.65.36.94.75.07.98.03.13.46.15.64.14.12.73.22.96.64.55.57.13.71.43.42.01.2

174.3

Recovery(%)

99953481111267712481842556691568150678384333664594343283431708265894920576760

50

scattered quartz silt, rare zeolites, rare radiolarian castsfilled with a mixture of chalcedony and clay, but thedominant component of the subunit is clay. Thereddish brown claystone in Sample 24, CC is underlainby a medium gray shale which is very finely laminatedby light gray carbonate. The laminae are lenticular andless than 1 mm in thickness. The core-catcher sampleindicates a transitional contact between Units 4 and 5.

Unit 5

Subunit 5a—Light Gray Nannofossil Limestone,Interbedded With Olive Marlstone and Black Shale

(Cores 25 through 27)This subunit differs substantially from the overlying

sequence. It is a light gray (N7) to medium gray (N5)massive limestone. The limestone is interbedded withmoderately soft, olive-gray (5Y4/1) and laminatednannofossil marlstone. Aptychi occur in the marlstone.The light gray limestone is bioturbated, slightlyrecrystallized, and composed of a microsparite

enclosing nannofossils. The marlstone is composed ofabundant clay, quartz silt, rare iron oxide(?) micro-nodules, traces of pyrite, and heavy minerals. Thin-section observations revealed rare feldspars, fish debris,and organic matter. Nannofossils are abundant andforaminifers are rare. Nannoconus is present in Cores 26and 27. Poorly preserved calpionelloids occur in traceamounts in Core 27. Casts of radiolarians replaced bycalcite are frequent throughout Unit 5, occurringmostly in the light gray limestone. The marl in Core 27becomes varicolored and encloses thin beds in oliveblack shale.

Subunit 5b—Nannofossil Limestone With Marl and Chert(Cores 28 to 32-5)

The top of Subunit 5b is an alternating nannofossil-bearing limestone and olive-gray (5Y/1), finelylaminated marlstone. The content of argillaceousmatter increases with depth. The argillaceousnannofossil-bearing limestone is pale yellowish brown(10YR6/2), finely laminated, and frequently

172


TABLE 2Lithostratigraphy at Site 367

Unit

1

2a2b

3

4a

4b

5a

5b

6

7

Lithology

Foraminifer-nannofossil marlwith quartz sand

Diatom-bearing radiolarian clayZeolitic clay with chert andporcellanite

Multicolored silty clay

Black shale

Variegated claystone

Light gray nannofossil lime-stone, olive marlstone, and blackshaleNannofossil limestone, marl,and chert

Reddish brown nannofossil-bearing argillaceous limestone,marl, clays, and chert

Basalt

Cores

1 through 7(0.0 to 255.0 m)

8(302.5 to 312.0 m)9 through 14

(331.0 to 338.0 m)

14, CC through 17(388.0 to 625.5 m)

18 through 23(636.0 to 787.0 m)

24(834.5 to 844.0 m)

25 through 27(891.5 to 948.5 m)

28 through 32-5(948.5 to 1089 m)

32-5 through 38-2(1089.0 to 1144.0 m)

38-2 through 40(1144.0 to 1153.0 m)(T.D.)

Age

Pleistocene to Miocene

Late EoceneEocene to late Paleocene

Late Paleocene/early Eocene toLate Cretaceous

Early Turonian to late Aptian/early AlbianLate Aptian to early Albian

Late Aptian/early Albian toHauterivian

Valanginian/Hauterivian toOxfordian/Kimmeridgian

Not older than Oxfordian toKimmeridgian

Figure 6. Fish vertebrae recovered from lithologic Subunit 4a.Core diameter is 6.5 cm.

bioturbated. Medium gray (N6) chert and medium lightgray and dark greenish gray (5GY6/1) procellaniteoccur sparsely from Core 29 to the base of Subunit 5b.Thin beds of olive-black shale alternate with limestonebeds in Core 28; poorly preserved calpionelloids(?)occur in trace amounts in Core 29. The composition ofSubunit 5b is similar to Subunit 5a. Aptychi arerelatively common in the marlstone. Low-amplitudestylolites first occur in Core 31. The boundary with the

underlying unit is placed at the top of the reddishbrown limestone sequence occurring in Core 32,Section 5.

Unit 6—Reddish Brown Nannofossil-bearingArgillaceous Limestone Interbedded With Marl,Clay and Chert (Cores 32-5 through 40)

The nannofossil-bearing argillaceous limestone islight brownish gray (5YR6/1) to dark reddish brown

173


(2.5YR2.5/5) with fine, wavy laminations. Thelimestone is bioturbated and frequently displays anodular texture. Reddish brown limestone alternateswith very light gray (N8) microcrystalline limestone,the latter being massive, mottled, and having stylolites.There is a slight change in composition and color fromCore 33 downward. Reddish brown limestonealternates with thin (less than 5 cm) greenish gray(5G5/2) claystone beds and laminae. The limestonebecomes more argillaceous toward the base of the unit.Porcellanite and chert occur sporadically but alwaysoccur above a clay or red marlstone bed. Threemicrofacies can be recognized on the basis of thebiogenic content. The Saccocoma-aptychi microfacies(Core 32, Section 5 to Core 35, Section 2) ischaracterized by very common planktonic echinoids(Sαccocomα) and aptychi fragments in the marlstone.The matrix is a nannofossil-bearing clayey micrite. Thelight gray limestone in this microfacies is composed ofmicrosparite with frequent casts of radiolariansreplaced by calcite. A change of microfacies occurs atthe top of Core 35, Section 3. Here a flood of long,parallel-oriented filaments (planktonic lamelli-branches) occurs. Core 36 has predominantly short fila-ments which show a lower degree of preferentialorientation parallel to the bedding planes. Sαccocomαand aptychi are rare. Radiolarians and nannofossilsreplaced by calcite are common. Filaments occur inboth the marl and the argillaceous limestone. The lightgray limestone of the filamentous microfacies is slightlyrecrystallized and the matrix is composed of micro-sparite. The marlstone in Cores 37 and 38, Section 1,form a third microfacies. They are highly argillaceouswith radiolarian molds filled by chalcedony and/orcalcite. Other biogenic components include Stomio-sphaera, and rare foraminifers, aptychi, spongespicules, and echinoid debris.

Unit 7—Basalt (Cores 38, Section 2 through Core 40)

This unit is black (Nl), aphanitic basalt with calciteveins and disseminated pyrite in the upper 20 cm.Altered angular clasts of the overlying sediment areincorporated in the upper 10 cm of the basalt. Thebasalt is vesicular, with fillings of celadonite(?) andglass. The overall appearance is sometimes massive andsometimes highly brecciated. The presence of twodarker, more massive intervals and an abruptappearance of vesicles indicates the possibilities ofseveral flow units.

Three different types of basalt were recognized fromthe study of four thin sections on the basis ofcomposition and texture. Type 1 and Type 3 are verysimilar in composition.

Type 1: Variolitic basalt with an intersertalgroundmass texture (39-2):

This basalt is composed of 40% plagioclase, 30%augite, 15% magnetite, 3% olivine, and 12% glass. Lathsof plagioclases (100 µm long) are randomly oriented.The extinction angle of the plagioclases suggests acomposition of Amo-Amo. They are usually clear, someshow sericitization and are replaced by epidote. The

pyroxene is probably augite and is granular in shape.Magnetite has a cruciform skeletal and prismatic habit.Olivine is slightly altered and chloritized. Glass islocally altered into a mixture of palagonite, chlorite orceladonite(?), and carbonate.

Type 2: Vitric basalt (Sample 40-1, 141 cm):

This basalt consists of 60% glass, 15% plagioclase,15% augite, and 10% magnetite. Plagioclase andpyroxene form microphenocrysts which are intimatelyintergrown and form feathery aggregates. The glass isclear and magnetite forms cruciform skeletal crystals.Chalcedony fills some of the vesicles and fractures.

Type 3: Trachytic basalt:

This basalt is composed of 40% plagioclase, 35%glass, 15% magnetite, and 5% augite. The groundmasshas a trachytic texture. Plagioclase has altered into amixture of sericite and epidote and the glass has alteredto palagonite. Magnetite has a skeletal cruciform habit.Augite was not observed, but some of the chlorite hascrystallographic outlines, suggesting that it is replacingaugite.

Summary

The most striking features of Site 367 sediments are:(1) almost continuous deposition from Upper Jurassicto Holocene; (2) cyclic character of sedimentation(Dean et al., this volume) and; (3) the similarity to theMesozoic lithologic sequences in the western NorthAtlantic (Leg 11, Sites 99, 100, 101, and 105; Hollister,Ewing, et al., 1972; Lancelot et al., 1972), and theMediterranean (Bernoulli, 1972), and to the outcropsexposed on Maio Island, Cape Verde islands(Stahlecker, 1934; Jansa et al., this volume).

The hole bottomed in altered basalt which containsseveral inclusions of sedimentary rocks. Age dates byK-Ar methods of these basalts give minimum ages of 88to 92 m.y. (Duncan and Jackson, this volume). Thesediment above the basalt shows slight recrystal-lization; however, there are no indications of strongthermal alteration.

The basalt is overlain by an Upper Jurassic reddishbrown limestone sequence in which radiolarian,filimentous, and Sαccocomα-aptychi microfacies arerecognized, all characteristic of pelagic facies of theTethyan Mesozoic. Pelagic lamellibranch and radio-larian limestone typically occur in the Middle Jurassicof the Apennines (Bernoulli, 1972), and the Sαccocomα-aptychi microfacies is typically found in the Kim-meridgian of the same region (Jansa et al., this volume).

The sedimentary structures in the marl and limestoneof unit 6 are more variable than those that occur in theoverlying units. Horizontal and inclined laminations,small-scale scouring, and small-scale slump features arecommon. These, together with the occurrence of thinlayers of intraclast breccia, indicate that during theMiddle to Late Jurassic, hydrodynamic conditions weremore variable than occurred later. This variability canbe explained by slightly shallower water depth, by amore variable current regime, local tectonic dis-turbances, or greater irregularity of bottomtopography.

174


A substantial change in sediment composition occursaround the Lower to Upper Cretaceous boundary (844to 890 m; Cores 24 and 25). Sediments below thisboundary are mostly carbonate but, above theboundary, terrigenous material is the dominantcomponent.

Lower Cretaceous limestone is overlain by lateAptian-early Albian to early Turonian black shalewhich has an organic carbon content of up to 28%. Thehigh organic content of the shale is interpreted to be inpart the result of a large influx of terrigenous organicdebris into the basin (Gardner et al., this volume).Reducing conditions favored the formation of thepyrite and iron monosulfides. The black shale lacksvisible bioturbation. The predominantly black color ofthe sediments, however, could obscure burrows.

The Upper Cretaceous multicolored hemipelagicsilty clay, which overlies the black shale, is composedmostly of terrigenous material. The conditions whichled to the alteration of oxygenated and reducedenvironments within the sediments (as evidenced by themulticolors) are interpreted to be the result offluctuating input of organic debris (Dean et al., thisvolume; Gardner ét al., this volume). The Eocenezeolitic clay which overlies the hemipelagic clay doesnot contain substantial coarse grained terrigenous com-ponents and we consider this to be a pelagic deposit.

GEOCHEMICAL MEASUREMENTSThe introduction to this volume outlines the

geochemical techniques used aboard ship for each ofthe parameters discussed below.

Organic Carbon

Table 3 summarizes the shipboard determinationsand a few shore based analyses (Texas A&M Universityand Shell Oil Company) of organic carbon content andorganic carbon to total nitrogen (C/N) ratios.Duplicate analyses were run on Core 1, Section 5, 144-150 cm, following squeezing for interstitial water.Agreement was within one standard deviation for bothorganic carbon and C/N. Samples were taken inadjacent facies in cores with laminated sediments, andoften showed marked differences in organic carboncontent. The highest organic content (307o) is in a thinlayer with plant debris in Core 26, Section 4, 28-29 cm.Core 19, Section 4, 0 cm, has an organic carbon contentof 6.7% with a C/N of 30.6 This section had the highestmethane concentration, 96.5%, in the interstitial gas.Organic carbon and C/N values are scattered becauseof the alternating organic-rich and organic-poor facies.Organic carbon values range from 0.05% to 0.3% withlow C/N values for the organic-poor facies but greaterthan 0.5% organic carbon and C/N ratios greater than10 in the organic-rich sediments.

Additional samples from Cores 18 to 22 were takenfrom the working half of the split core three monthsafter the cruise. These samples had much higherorganic carbon contents than adjacent samples takenonboard. Samples analyzed by Scripps Institution ofOceanography (SIO) were also high in this region.

TABLE 3Results of Carbon and Nitrogen Analyses From Site 367

Sample(Interval in cm)

1-5, 144-1501-5, 144-1502-1, 83-842-2,62-634-3, 120-1508-3, 130-1508-4, 46-488-4, 50-52

14-4,41-4214-4,51-5215-3, 13015-4,91-9215-4, 105-10617-4,115-11617-4, 118-11918-2, 144-14519-4, 0-119-4, 20-2519-4,44-4520-2, 7-822-5, 104-10525-3, 38-3925-3, 42-4326-4, 28-3931-2, 37-38

32-5, 97-98

33-3, 92-9333-3, 93-94

Depth(m)

6688

68310311311387387480481481625625640653653653688728898898919

1062

1090

11101110

% Org;anic C(total dry wt. basis)

X

0.5820.5701.1320.3510.2250.2050.3352.5900.0930.1310.1540.1720.0990.1393.897

37.216.6994.09

18.5416.2921.06

3.9880.139

25.0700.521

0.046

0.0520.034

SD

0.0120.0060.0450.0270.0250.0080.0330.0580.0080.0320.0300.0420.0750.0060.105

0.569

0.0040.0051.0860.015

0.006

0.0020.011

C/N(atomic ratio)

X

10.110.116.48.27.54.65.8

13.16.96.54.85.74.23.7

28.144.730.5

34.125.423.825.7

8.618.531.5

2.0

2.12.0

SD

0.170.130.721.040.370.450.090.112.803.521.451.030.260.420.37

2.86

1.022.771.652.83

0.55

0.280.47

Remarks

ClayClay

ClayBlack clayClayClaySilty claySilty claySilty clay

TAMUBlack shaleLECO-ShellTAMUTAMUTAMUDark bandLimestonePlant debrisArgillaceous

limestoneArgillaceous

limestoneShaleSiliceous

Limestone

These, like the additional samples, were not kept frozenprior to analysis. The reason for this difference is notclear, but additional studies are in progress. Noapparent contamination was observed.

Interstitial Gas

Evidence of gas was present beginning with Core 17(625 m subbottom) as gas bubble formation within thecore as well as bulging end caps on the core liner. Gassamples were taken through the core lines or throughend caps. The results are given in Table 4. Hydro-carbons above propane were not detected.

Carbonate Bomb Measurements

The routine carbonate measurements are tabulatedin Table 5.

Interstitial Water ChemistryTable 6 lists and Figure 7 plots the results of

interstitial water from squeezed samples. No interstitialwater samples were taken below Core 23, Section 1,144-150 cm, because deeper sediment was tooconsolidated to liberate any water.

Basalt GeochemistryA sample of basalt from Core 39, Section 2, 28-29

cm, was washed, dried, and powdered, then analyzedfor water and carbonate content. This sample waschosen for its homogeneity and lack of visible calciteveins. Analyses for H2O and CO2 were made withHewlett-Packard CHN analyzer. Water content was3.8%. Carbonate content was 0.96% as calciumcarbonate. The standard used is a powdered basalthaving 3.0% H2O and 1.6% CaCO3.

175


TABLE 4Results of Interstitial Gas Analyses From Site 367


17-3, 2518-4, 2519-2, 150b

19-4, 12020-4-5022-6, 9423-2, 0 b

24-3, 0b

25-4, 30

a Methane

SubbottomDepth

Bottom ofCore (m)

625644654654692730787844920

(Ethane + Propane)

N2 + O2 CH4

(% of total)

4.04.59.52.95.34.16.1

92.28.7

95.494.989.996.593.895.293.7

5.391.1

co2

5015548847755803748858791998

240001437

C2H6(Carle)

C2H6(Bendix)

(ppm of total gas)

687752254533715342228

—641

876763329638563353211—

694

C 3 H 8

98108

0104212100

0-79

Ma

E+P

1215108927331300121021024441

—1312

End cap samples, all other samples through core liners.

TABLE 5CaCO3 - Carbonate Bomb Method Leg 41 Site 367


1-5,49-502-2, 63-644-2, 56-57

14-3, 122-12315-3, 63-6416-3, 110-11117-3, 73-7418-3, 94-9521-3, 45-4623-2, 70-7124-2, 124-12524-3, 47-4825-3, 91-9227-3, 84-8529-2, 40-4129-2, 106-10730-2, 141-14232-3, 133-13433-1, 67-6834-2,50-5135-3, 86-8836-3, 63-64

Depth(m)

71066

386477543620641695786842843895943998999

102810871108111311201130

% CaCO3

414269

00000

34000

94929796925878918051

Lithology

Nannofossil marlNannofossil oozeNannofossil marlZeolitic clayClayey sandPorcelliniteClayShaleBlack shaleClayClaystoneClaystoneLimestoneLimestoneLimestone with chertLimestoneLimestoneLimestoneClayLimestoneLimestoneArgillaceous limestone

PHYSICAL PROPERTIES

Four major lithologic units at Site 367 are distinctlycorrectable with the physical properties data. (SeeTrabant, this volume for tabulation of data.)

Bulk PropertiesBulk property measurements were made for water

content, void ratio, bulk density, porosity, and specificgravity. Bulk properties are interrelated so onlyporosity is shown in the graphical presentation. Theplot of porosity versus depth (Figure 8) shows a lineartrend, with a good grouping of the values from withinthe lower limestone unit where the porosities are lessthan 30%. The dashed line separates limestone from theoverlying clay and shale. Large variability occursbetween adjacent limestone samples only a fewcentimeters apart because certain limestones are"cleaner" or "purer" than others. The "cleaner"limestones are less porous than the "dirtier" ones.

Shear StrengthDue to the limited number of cores retrieved within

the uppermost 250 meters of the section, shearstrengths were obtained only on two cores.

TABLE 6Results of Interstitial Water Analyses From Site 367


1-5, 144-1504-4, 144-1508-4, 144-150

14-2, 144-15015-4, 144-15016-5, 140-15018-3, 140-15021-4, 144-15023-1, 140-150

Subdepth(m)

7.569.5

308.5381.5479.5547.5640.5698.0779.0

pR

7.467.387.207.407.74

_7.017.017.48

Alkalinity(meq/kg)

4.683.468.913.323.052.272.522.301.29

Salinity(7oo)

34.934.933.632.433.030.232.232.232.4

Ca++

(m moles/1)

11.298.85

14.5318.0923.6025.5729.5537.4446.08 .

Mg++

(mmoles/1)

52.3751.4246.0342.6243.3838.0939.3431.8236.29

cr(7oo)

19.2719.2719.2719.2718.9717.6018.9719.3118.91

Remarks

DisturbedDisturbed

Disturbed

176


Ca++ (mmoles/l)0 10 20 30 40 50 60

100

200

300

~ 400

500

600

700

800

Mg+ + (mmoles/l)0 10 20 30 40 50 60 17 18 19 20

6.50

pH7.0 7.5 8.0

Alkalinity (meq/kg)0 2 4 6 8 10 12

Salinity (°/oo)30 31 32 33 34 35

100

200

300

400

500

600

700

800L

Figure 7. Plots of interstitial water analyses from Site 36 7.

177


100 -

200 -

300 -

400 -

500 -

600 -

900 -

1000

-

-

-

-

\

\©

LIMESTONE

©

/

© /©

" © © |© © U

I I

0

ΔCHERT

©

/ ©©©/©

:LAY AND SHALE•/^p

\ / '°

/©

\ /

X©©

©

1

/ ©

© ©

\

\

\

© ©

© ©

® ©

/

/

LithologicUnits

1

2a

2b

3

4a

4b

5a

5b

6

7

40 50

Porosity (%)

Figure 8. Plot of porosity versus depth in Site 367. Thesolid line is a general regression line of the data and thedashed line separates limestone samples from clay andshale samples.

Acoustic Velocities

The compressional velocity (Vp) was measured usingthe Hamilton Frame velocimeter. These values arehighly variable, ranging from 1.56 km/sec within theuppermost, soft, unconsolidated clay to 4.75 km/sec inthe lowermost clayey limestone unit. The velocity dataare plotted in Figure 9.

Velocities measured in the horizontal directiongenerally are higher than those in the vertical direction.The visual homogeneity of the limestone can becorrelated to the velocities. The more laminated or"dirty" the limestone, the lower the velocity, withdifference extremes ranging up to 1.0 km/sec. The widescatter obtained within this limestone-marlstone unit isapparent in Figure 9. A velocity of 4.26 km/sec wasobtained within the homogenous fine-grained basalt oflithologic Unit 7.

Summary

Although the lithologies at Site 367 may besubdivided into over a half dozen units, only four majorgeotechnic units can be recognized.

Unit 1: A silty clay unit (0 to 625 m whichcorresponds to lithologic Units 1, 2, and 3) composedof nannofossil foraminifer marl and clay, diatoma-ceous clay, zeolitic clay with a few cherts (see porosityvalue at 373 m), and a multicolored variegated siltyclay. This sequence reflects a transition from unconsol-

100

200

300

400

500

I 6 0 0

700

800

900

1000

1100

1.5

•

2.0

+

2.5

+

Velocity (km/sec) Lithologic3.0 3.5 4.0 4.5 5.0 Unit

+

• +

+ +

• + +.+ * J

Limestone

basalt

1

2a

2b

3

4a

4b

5a

5b

6

7

Figure 9. Plot of sound velocity versus depth in Site 367.

idated to well-indurated silty clay with Vp values below2.0 km/sec.

Unit 2: A gassy shale and mudstone zone which hasa few intercalated limestones. Velocities are tooattenuated to be measured due to the presence of gas.The relative percentage of the intercalated limestone inthis sequence increases towards the base, where the unitbecomes entirely limestone. Porosity values within theshales are meaningless due to the presence of gas. Thespecific gravity values, however, strongly reflect thelarge amount of organic matter with values as low as1.65 g/cc.

Unit 3: This unit consists of a large variety oflimestones which exhibit variations in the physicalproperties according to their carbonate content.

Unit 4: The basalt recovered at the base of the holewas measured only for Vp and specific gravity. Calciteveins are present, although their effects on the acousticvelocities were not determined.

BIOSTRATIGRAPHIC SUMMARY

Sediments from Site 367 range in age fromQuaternary to Upper Jurassic. Preservation of thematerial is generally moderate to poor. Coring wascontinuous only between Cores 9 and 14 and betweenCores 33 and 40. The combination of these two factors,discontinuous coring and poor fossil content andpreservation, resulted in much uncertainty inidentifying the presence or absence of hiatuses ordiscontinuities.

The early Aptian to Late Jurassic section containsabundant nannofossils but only scattered occurrencesand abundances of calcareous and agglutinated benthic

178


foraminifers and radiolarians. Ostracode casts, aptychi,Saccocoma sp., pelagic pelecypods, Tintinnids, andammonites occur intermittently. The predominance ofnannoplankton, high diversity of calcareous fossils andpresence of aptychi suggests these sediments belong to adeep-water facies.

Faunas and floras of Eocene to upper Paleocene ageshow a domination by radiolarians, with poorassemblages or absence of planktonic foraminifers andnannofossils. These observations, together with thecomposition of the benthic foraminifers, suggest thatthe sediments accumulated in a bathyal environmentwith fluctuating rates of carbonate dissolution.

ForaminifersPlanktonic and benthic foraminifers range in age

from Pleistocene to Upper Jurassic.

CenozoicThe Pleistocene is represented by the Globorotalia

truncatulinoides Zone in Cores 1 and 2. A Pleistoceneage not younger than 80,000 years B.P. is indicated bythe presence of Globorotalia tumida flexuosa. Cores 3through 5 contain a Pliocene microfauna, whichincludes: Globorotalia exilis, G.cf. tosaensis, G.miocenica, G. multicamerata, Globorotalia cf.margaritae, Sphaeroidinella dehiscens, Globorotaliacrassaformis Gr. Tumida, Globigerinoides conglobatus,Globigerina rubescens, and G. digitata. These species areaccompanied by reworked Miocene foraminifers. Thecore catcher of Core 6 contains a mixed planktonicforaminifer fauna, the youngest elements of which areGlobigerinoides trilobus, Cassigerinella chipolensis andGlobigerina angustiumbilicata, indicating an age notyounger than middle/lower Miocene. The bulk ofplanktonic foraminifers are of Oligocene age. Theyinclude Globigerina ciperoensis, G. ouachitaensis, G.praebulloides. Eocene species Globorotalia subbotinaeand Acarinina sp. are present, and also a Cretaceousspecies, Hastigerinoides sp., was found. Benthicforaminifers include representatives of differentecological groups; shallow water inhabitants, such asAmmonia beccarii, Elphidium crispum, andAmphistegina are mixed with deep dwellers such asMelonis, Pyrgo, Virgulina, Pullenia, Ehrenbergina,Cassidulina, Florilus, Planulina, Dentalina, Fissurina,Dorothia, and Uvigerina. Preservation of theforaminifers is good to moderate. Core catchers 7through 9 contain either no stratigraphically significantforaminifers or are totally barren of foraminifers.Middle Eocene planktonic foraminifers are rare to fewand poorly preserved. Core 10 contains a singlespecimen of Acarina, indicating an age not youngerthan middle Eocene. Core 11 has an assemblage whichsuggests a middle Eocene age. Core 12 is given an age ofearly Eocene. Benthic foraminifers are calcareous deep-water species such as Pleurostomella, Cibicides,Bulimina, Aragonia, Gyroidina, Lentinculina. Cores 13and 14 are barren of foraminifers.

MesozoicCores 15 through 18 contain specific Upper

Cretacous assemblages which are typical of the flysch

and the noncalcareous shale facies of the Alps withprimitive and higher developed agglutinated benthicforaminifers. The only calcareous foraminifer found isGyroidina. The only fauna recovered in Cores 15, 17,and 18 include Hedbergella planispira, H. infracretacea,H. cf. Amabilis, Heterohelix sp., and Loeblichella sp.They suggest only a Late Cretaceous age. Theforaminifer faunas are accompanied by fish debris andBryozoa, the last of which indicates admixtures fromshallower water depths into the bathyal sedimentationregime. Planktonic foraminifers of Cores 19 through 21indicate a Cenomanian age. They are small and haveabundances ranging from abundant to rare. Thefollowing taxa were determined: Hedbergelladelrioensis, H. trochoidea, H. infracretacea, H. amabilis,H. globigerinelloides, Globigerinelloides caseyi,Guembelitria harrisi, and Heterohelix moremani. InSamples 367-19-3, 138-140 cm, one specimen ofPraeglobotruncana was found. In Samples 367-21-6, 35-36 cm, and 21, CC, some specimens of Schackoinacenomana and Hedbergella brittonensis were found.Fish debris is common but benthic foraminifers areextremely rare. Core catcher 22 contains an Albianfauna of Ticinella primula, Hedbergella amabilis, H.planispira, H. infracretacea, H. delrioensis, H.simplicissima, Clavihedbergella simplex and Globi-gerinelloides sp. The preservation of planktonicforaminifers is moderate. The benthic foraminiferfaunas are rare and fish debris is common. Core 23 isbarren of foraminifers. Core catcher 24 contains asmall-sized but abundant and well-preservedplanktonic foraminifer fauna. The assemblage includesHedbergella aff. kugleri, H. aff. graysonensis, H. infra-cretacea, H. globigerinelloides, Globigerinelloides sp.,Gubkinella sp. sp., and very small Hedbergellaspecimens. We have assigned a lower Aptian toBarremian age to this assemblage. Benthic componentsof the foraminifer fauna include various agglutinatedforms and some Lagenids. This assemblage suggestsconditions perhaps similar to those of the overlyingAlbian and Cenomanian sequence (Cores 19 through22); a deep-water environment with restricted circula-tion. Cores 25 and 26 contain only a rare benthic faunawith poor preservation. A Neocomian age is based on acomparison with Leg 11, Site 105, where similar faunasoccur (Luterbacher, 1972). Foraminifers are missing inSample 27, CC. Samples from Core 28, Section 6, arecharacterized by the same assemblage of benthicforaminifers as occurs in Cores 25 and 26. Specimens ofDorothia praehauteriviana are common, which wereassigned a ?Valanginian age on Leg 11 (Luterbacher,1972). The higher proportions of calcareous benthicforaminifers in comparison to the faunas of theoverlying black shales suggest a paleoenvironmentinfluenced by better circulation patterns. Cores 29through 31 are barren of foraminifers. Core 32 has anassemblage of planktonic foraminifers consisting ofSpirillina sp. sp., Lentinculina, Nodosaria, Spiro-phthalmidium, and Rhabdammina. Cores 33 and 34 arebarren of foraminifers. Cores 35 through 37 contain thesame faunas as Core 32. The fauna indicates an upperJurassic age.

179


Calcareous Nannoplankton

The preservation of coccoliths varies from poor togood. Three stratigraphic intervals are identified: (1)the Pleistocene to middle Miocene (Cores 1 to 6); (2)the upper lower Eocene (Cores 12 to 13); and (3) theCretaceous to Upper Jurassic (Cores 16 to 38). Theresults from the upper part of the site (Cores 1 to 17)are based mostly on investigations of core catchers, butin the lower part of this site (Cores 18 to 38) results arebased on identification of coccoliths from samples ofthe core sections.

Cenozoic

Pleistocene floras were recovered in the uppermostcores (Cores 1 and 2). Coccoliths are abundant and wellpreserved. Both cores belong to the Gephyrocapsaoceanica or Emiliania huxleyi zones. The Emilianiaovata Subzone was not observed. The subzone may bepresent in this section but the 36.5 meter uncoredinterval lies between Core 2 and Core 3. Thepreservation in Core 1 is better than in Core 2. Thecentral bridges of the species Gephyrocapsa oceanica arenot always observed in this core indicating thecoccoliths are partially dissolved. Also somecontamination of middle Miocene to upper Pliocenespecies is seen. Pliocene coccoliths are found in Cores 3through 5. Core 3 is the Discoaster surculus Subzone.Common and generally well preserved PlioceneCoccolith assemblages occur in Core 4 indicating theDiscoaster tamalis Subzone. The samples are rich indiscoasters, especially D. pentaradiatus, which indicatewarm waters, but many of them are broken. Nosignificant overgrowth was observed. Dissolution ofcoccoliths, but not of discoasters, was observed in Core5. Some middle to upper Miocene and Eocenecontamination was found. The assemblages in Core 6are not older than middle Miocene. The age probablycorrelates to the middle Miocene Sphenolithusheteromorphus Zone, based on the presence ofDiscoaster challengeri, Discoaster braarudii, Discoasterexilis, Helicopontosphaera kamptneri, Discolithinavigintiforata, and Spenolithus heteromorphus. Somereworked Paleogene species were noted. No significantovergrowth was observed, but discoasters and mostcoccoliths are partially dissolved. Coccoliths arepractially absent in all core catchers of Cores 7 to 11. InSamples 7, CC, 10, CC, and 11, CC only, one to threeCoccolith specimens were observed and these probablyresult from contamination although they may reflect avery bad state of preservation. The core catcher of Core12 contains common and moderately dissolvedspecimens assigned to the lower Eocene Discoasterlodoensis Zone, based on Coccolithus crassus and D.lodoensis. An upper lower Eocene assemblage of rareand poorly preserved coccoliths is found in Core 13.Coccoliths are practically absent in Cores 14 to 17.Several partially dissolved coccoliths were seen,however, they are mostly contamination.

Mesozoic

The first Cretaceous Coccolith {Tetralithus obscurus)appears in Core 16, and is not older than Santonian

age. Cores 16, Sections 6 through 18, are of Coniacianage. Cores 19 through 22, Section 5, are late Albian toearly Turnonian in age. The assemblage for this part ofthe Cretaceous includes Vagalapilla matalosa, Tetra-lithus obscurus, Eiffellithus turriseiffeli, Lithastrinusfloralis, Corollithion signum, and Chiastozygusamphipons. Coccoliths are rare to abundant, andpreservation is generally poor to moderate. EarlyCretaceous coccoliths are found in Sample 22, CCthrough Core 32, Section 3. Coccoliths of late Aptian toearly Albian age are found in Sample 22, CC throughCore 25, Section 1, 6-7 cm. The species include:Parhabdolithus angustus and Lithastrinus floralis. Theabundance and preservation of species in Core 24 isbetter than in Cores 22 and 23. Early Aptian assem-blages of coccoliths were observed only in Sample 25-1,16-17 cm through Core 25, Section 3. A relatively goodCoccolith assemblage of Barremian age is found in Core5, Section 4 and in Core 26. The upper boundary of theBarremian is dominated by the last occurrence ofNannoconus colomii. The coccoliths are well preservedand common to abundant. A Valanginian andHauterivian assemblage is present in Cores 27 through30, Section 1. The upper limit is defined by the lastoccurrence of Cruciellipsis cuvillieri, which has a knownrange from early Berriasian to Hauterivian (Thierstein,1971). The lower boundary (base of Hauterivian) is thefirst occurrence of Diadorhombus rectus. Thepreservation of the Coccolith assemblages is poor tomoderate and the abundance is few to common. Thebase of the Cretaceous is represented by the Berriasianin Core 30, Section 2 through Core 32, Section 3. Thelower boundary of the Cretaceous is characterized bythe first occurrence of Lithraphidites carniolensis,Nannoconus colomii, and Cruciellipsis cuvillieri. Thecoccoliths are few to common with poor to moderatepreservation. Core 32, Sections 4 and 5, belong to theTithonian. This stratigraphic level is based on thepresence of Parhabdolithus embergeri and the absenceof Lithraphidites carniolensis, Nannoconus colomii, andCruciellipsis cuvillieri. The coccoliths are common withmoderate preservation. According to the zonation ofBarnard and Hay (1974) this stratigraphical levelbelongs not to the Tithonian but to the late Kim-meridgian Parhabdolithus embergeri Zone. We use thenomenclature used by Wilcoxon (1972) for DSDP Leg11, Site 105, giving us the advantage of possiblecorrelation of the two sites. The coccoliths of Cores 32,Section 5, through 38 are rare to few arid poorlypreserved. The assemblage of coccoliths includesCyclagelosphaera margareli and Callolithus martelae.Both species first appear in the Oxfordian (Bukry andBramlette, 1969).

RadiolariansRadiolarians are present within three stratigraphic

intervals: the upper Pleistocene, the upper and lowerEocene, and the Lower Cretaceous. The Pleistoceneand Eocene sections contain sufficiently well preservedassemblages to allow approximate age assignments tobe made. Radiolarians in the Lower Cretaceoussections are rare, poorly preserved, and fragmented.The siliceous skeletal material has generally been

180

replaced by pyrite or calcite. Reliable age assignmentsfor the Mesozoic samples were not possible because ofthe poor preservation of most of the fragments.

Cenozoic

Core 1 contains rare specimens of moderately wellpreserved radiolarians indicative of a Pleistocene age.These taxa include Ommatartus tetrathalamus,Lamprocyclas maritalis polypora, Siphocampe corbula,Axoprunum angelinum, and Pterocanium trilobum. Thepresence of A. angelinum in Sample 1, CC suggests anage greater than 0.4 m.y. The base of the Pleistocenewas not identified because Cores 2 through 7 weredevoid of radiolarians. Scattered middle and earlyTertiary forms, Calocycletta virginis, Cannartuslaticonus, Stichocorys delmontensis, and Rhopalocaniumsp., are included with the Pleistocene species. Thepresence of reworked contaminants is not surprising inview of the physiographic location of this site. Outcropsof Tertiary strata along the adjacent continental marginare a likely source for such material. Core 8 containscommon specimens of moderately preserved radio-larians diagnostic of the upper Eocene Thyrsocyrtisbromia Zone. Core 9 contains scattered fragments ofupper Eocene taxa, but there are insufficient specimenspresent for a reliable age assignment. Core 10 containsrare and very poorly preserved fragments of lower andmiddle Eocene species consistent with an agecorresponding to the Theocampe mongolifieri or T.cryptocephala cryptocephala zones. Core 12 contains arare and poorly preserved assemblage which corre-sponds to the lower Eocene Phormocyrtis striata striataZone or Buryella clinata Zone. Core 13 is devoid ofidentifiable radiolarians. Core 14 can be assigned to theBekoma bidartensis Zone of lowermost Eocene oruppermost Paleocene age, based on common butpoorly preserved specimens of Buryella tetradica,Lophocyrtis biaurita, Phormocyrtis turgida, Theco-sphaerella rotunda, Lithocyclia archaea, and Stylo-sphaera coronata sabaca. Radiolarians are absent in thePaleogene sediments below Core 14. There is noevidence of reworking or redeposition in any of theEocene radiolarian assemblages, although theabundance of the diagnostic forms is not sufficient torule out the possibility of reworking.

MesozoicPoorly preserved radiolarian fragments were

identified in several samples which range in age fromthe Cretaceous through Upper Jurassic. Virtually allradiolarian fragments have experienced diagenesis,with silica replaced either by pyrite or calcite.Radiolarian fragments in the varicolored siltstones andmudstones were almost exclusively replaced by pyrite.Scattered radiolarian fragments were also present inwashed samples and in thin sections from the lithifiedwhite limestone units. Most of these forms were totallyreplaced by calcite, with details of the original testmorphology obliterated. Mesozoic radiolarians in thenonsilicified sediments examined from Cores 15through 28 are either absent or altered to pyrite.

The pyritized radiolarians are generally too poor toattempt any age assignments. The exceptions are


Sample 26, CC which, on the basis of the presence ofLithocampe elegantissima and the general aspect of thefauna, is considered Albian-Aptian, and Core 28,Section 2, 44-54 cm, which is Neocomian based on thepresence of a member of the Sphaerostylus lanceolagroup. Siliceous radiolarians from Cores 28 to 32 aretoo poor or too sparse to indicate anything but a broadNeocomian to Late Jurassic age. One exception is Core29, Section 2, 26-27 cm, which contains Sethocapsacetia and S. trachyostraca representing the Sethocapsatrachyostraca Zone. Samples from Cores 34 to 37contained more abundant, slightly better preservedradiolarians but, because radiolarians in the LateJurassic are not well enough known, the age assign-ments are based on foraminifer and nannofossil data.

ACCUMULATION RATESThe computation of Neogene accumulation rates

follows the same time scales used for Site 366 (thisvolume). The Cretaceous and Jurassic time scales havebeen adapted from Berger and von Rad (1972) and vanHinte (1972, 1976). The stratigraphic dates given arebased on foraminifers, nannofossils, and radiolarians,as well as calpionellids and ammonites for one sampleat the Jurassic/Cretaceous boundary. No attempt hasbeen made in our calculations to correct forcompaction. Only crude estimates can be given foraccumulation rates, due to spot coring in most parts ofthe site, and to poor faunal preservation, abundance,and diversity.

The Pleistocene and Pliocene are characterized byhigh accumulation rates (Figure 10) as shown by largeamounts of redeposited faunal components. Mioceneand Oligocene accumulation rates are difficult toestimate because sufficient data are lacking. However,if gaps are present, they cannot exceed values of 11m/m.y. for upper Miocene and 2.3 m/m.y. for Oligo-cene and lower Miocene. Accumulation rates duringthe Eocene are 6 to 7 m/m.y., which is lower than thatof the Eocene at Site 366, Core 14 (rise). Age dates areinsufficient for the Paleogene and part of the UpperCretaceous. It is impossible to decide whether there aregaps or not in this section, because of intermittentcoring. Accumulation rates for Cenomanian to Aptianblack shale are about 20 m/m.y. The Early Cretaceousvariegated claystone and upper parts of the white anddark limestone, have accumulation rates of 12.ym/m.y. The chert-bearing parts of the lowerNeocomian show values of about 4.8 m/m.y. UpperJurassic red and brown limestone and marlaccumulated at 9.2 m/m.y.

CORRELATION OF SEISMIC REFLECTIONPROFILES WITH DRILLING RESULTS

The correlation is established mainly from the profilerecorded by Valdivia several months after the cruise(Figure 11). This profile shows the presence of a firstreflector barely visible at about 0.08 sec below the seafloor. This reflector marks the top of a zone of darkreflections near the base of which a second reflector isdiscernible at about 0.38 sec. This second reflectorcorrelates with Horizon A visible in most of the CapeVerde and Canary basins. At about 0.7 sec below the

181


U. CRETACEOUS L. CRETACEOUS JURASSIC

CORENUMBER

Figure 10. Plot of accumulation rates at Site 367.

sea floor begins a reflecting zone that extends down toabout 0.8 sec. The lowermost part of the record shows arelatively thick zone of reflectors beginning gradually atabout 1.1 sec. The upper part of this lowermostreflecting zone appears clearly of sedimentary origin.The lower half, below about 1.18 sec near the site,however, shows a subtle but definite change incharacter that can be interpreted as basaltic basement.

The first reflector at about 0.08 sec probablycorrelates with the occurrence of sand layers in Cores 3and 4. The correlation cannot be very precise becauseintermittent coring prevents a good comparisonbetween the facies present above and below that level.We assume that most of the section between about 50and more than 160 meters consists of interbedded sandand marl responsible for the highly reverberating zonepresent in the upper part of the profiler record. Thereflector at 0.08 sec is barely visible in that zone andmight correspond with more massive sand accumula-tion than above.

The reflector at about 0.38 sec below the sea floorcorrelates well with the youngest occurrence of chert inthe hole at about 320 to 300 meters subbottom, andtherefore can be considered as equivalent to Horizon Afrom the western basins. Such a correlation implies anaverage sound velocity of about 1.7 km/sec for theinterval between the sea floor and Horizon A. Such avalue appears reasonable for a section supposed toconsist mainly of marls. It also agrees quite well withthe velocities measured on samples.

The correlation between the lower reflectors and thelithology is more problematic. The reflector at 0.7 secshows an acceptable correlation with the top of theblack shale unit, encountered at about 620 meters, if avelocity of 1.85 km/sec is inferred for the overlying siltyclay interval. The reflector at 0.8 sec could correspondwith hard dolomitic beds within the black shale. A hardlayer of dolomite was encountered at about 700 metersand it is possible that several other layers or nodulesoccur around that level. If we correlate the reflectorwith hard layers at about 715 meters, then the soundvelocity for the interval between the reflectors observedat 0.7 and 0.8 sec, respectively, would be 1.9 km/sec. Inany case, this correlation shows that this reflector is notequivalent to Horizon ß from the western basin butrather corresponds with Horizon A* correlated withthe top of the black shale unit in the North AmericanBasin (Ewing, Hollister, et al., 1972).

No well-defined change in the lithology accounts forthe presence of the moderately strong reflector at 1.1sec below the sea floor. The major change in lithologyseems to be the transition between the variegatedclaystone of Core 24 and the underlying limestone. It isnot possible, however, to correlate this change with thereflector at 1.1 sec if reasonable sound velocities areconsidered. The reflector at 1.1 sec might correlate witha break in the drilling rate observed at about 1005 to1010 meters. If this interpretation is correct, then thesound velocity for the interval comprising the lowerpart of the black shale and the upper part of thelimestone would be about 1.95 km/sec. The top of thelimestone could be rather transitional, and examinationof the seismic profile recorded while approaching thesite shows that a moderate reflector which could beconsidered as the equivalent of Horizon ß marks thattransition. At the drill site this reflector would bemasked by the reverberation of the reflector at 0.8 sec(Figure 11).

Below that level we can correlate a barely visiblechange in the character of the lowermost reflectingzone, at about 1.2 sec, with the top of the basalt. Thiswould yield an average velocity of 2.7 km/sec for thelimestones and argillaceous limestones.

SUMMARY AND CONCLUSIONSThe most impressive result obtained at Site 367 is the

striking similarity between the succession of Mesozoicfacies sampled at this site and those described in thewestern North Atlantic (Hollister, Ewing, et al., 1972;Lancelot et al., 1972). This confirms the symmetricalevolution of both sides of the North Atlantic during theMesozoic, prior to the major changes caused by widecommunication with other oceanic basins and onset ofvigorous thermohaline circulation sometime during theearly Tertiary. This evolution started with thedeposition of deep-water carbonates which becamecovered by clays when continuous subsidence—causedby the regularly increasing distance from the Mid-Atlantic Ridge—brought basins below the level of theCCD. The schematic picture simply derived from thesea floor spreading concepts is complicated by theoccurrence of black shales above the carbonatesequence.

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ZEOLITIC CLAY AND CHERTSILTYCLAY

Drilling break-

Figure 11. Correlation of drilling results with seismic reflection profile at Site 367. fValdivia 10-1975 seismic profile).

We shall summarize here the vertical succession offacies and discuss briefly their significance in terms ofenvironmental evolution of the basin. Figure 12 is agraphic summary of the lithology, biostratigraphy,sonic velocity, age, and drilling rates of Site 367.

BasaltThe occurrence of basalt in Core 38 at 1146 meters

below the sea floor was somewhat of a surprise becausethe seismic reflection profiles recorded over the siteprior to and during the cruise did not show reflectionclearly characteristic of the basement. The basalt is finegrained and fractured with numerous calcite-filledveinlets. It is, in places, brecciated and also containsinclusions of completely recrystallized sediment (chertand carbonate). The uppermost centimeters appearrelatively glassy. It has all the appearances, bothmacroscopically and in thin sections, of the basementrocks already cored at many previous DSDP sites anddoes not show any definite increase in grain size withdepth. The contact with the sediment does not showany good evidence of thermal alteration. However,because the rocks are highly recrystallized bydiagenesis, it is impossible to exclude completelycontact metamorphism.

The age of the basement in this area was expected tobe older than middle Oxfordian because the lowermostreflector was interpreted as reflector C by comparisonwith the profiles recorded off Morocco on the basis thatit appeared to be the lowermost reflector of sedi-mentary origin visible on the record. This reflector atSite 367 cannot be followed easily westward to itscontact with basement, however, because of theorientation of the Vema 29 profile (Figure 2).Unpublished data, made available to us just prior tothis cruise, show that Site 367 is not as far from theboundary of the quiet magnetic zone as we had inferredfrom its distance to the margin, because the quiet zoneappears exceptionally narrow off the widely progradingSenegal continental shelf (Figure 1). If we extrapolatethe 1/2 spreading rate of about 2.2 cm/yr calculatedfrom the Mesozoic magnetic anomalies dated byLarson and Pitman (1972), then the age of the basementat Site 367 could be expected to be approximately threemillion years older than at Site 105. Paleontologicalresults from the study of the lowermost sediments arenot precise enough to distinguish between these ages.Radiometric age determinations performed after thecruise indicated a Cenomanian age for the basalt.Alteration of the rocks, however, was evident and the

183


CORESDEPTH

LITHOLOGY

BIOSTRATIGRAPHIC ZONATION

FORAMINIFER NANNOPLANKTOI\ RADIOLARIANSis

DRILLING RATE(min. per meter)

50

100

150

200

250

150.5

— • 160

236

245.5

350

• 302.5

312

•331

• 340.5

-350

-359.5

-369

-378.5

•388

400

Foraminiferal nannomarls iπterbeddedwith silty clayand sand

(Unit 1)

—A—

•473.5

Diatom-bearingradiolarian clay

(Unit 2a)

Zeolitic clay with chertand porcellanite

(Unit 2b)

Multicolored silty clay(Unit 3)

Quaternary

1 SQ- O

2 4 6 8 10 12

Not olderthan Pliocene

1.56

Mixedassemblagesnot olderthan Pliocene

D. brouwerito

C. rugosus

Mixedassemblagesnot olderthan middleMiocene

1.66

middleEocene

T. c. cryptoe.?

NP12-N14

NP12

B. bidartensis

Paleocene? -Late Cretaceous

Figure 12. Graphic summary oflithology, age, biostratigraphy, sonic velocity, and drilling rates of Site 367.

184


500

CORESDEPTH

(m)

LITHOLOGYBIOSTRATIGRAPHIC ZONATION

FORAMINIFER NANNOPLANKTON RADIOLARIANS


550

600

-616

- 625.5

-636

r 644.5650

700

7 5 0 -

800 -

850

777.5

— -787

834.5

844

900 -

-891.5

-901

950 -

1000 - 29996

I—|-1005.5

TX:

Multicoloredsilty clay(Unit 3cont'd.)

LateCretaceous

Late Cretaceous

(gradational)

Black shale withoccasional carbonate(siderite?) nodulesand beds

(Unit 4a)

Late CretaceousCenomanian

FJöt oldTr tFan_ja_te A)bian_.Hate Aptian

_ early Turonian

late Albian-Turonian

2? 2 •-

EarlyCretaceousAlbian

P. angustus-P. cretacea

liBlack shale(Unit 4a confd.)

P. angustus

Variegated claystone(Unit 4b)

>•- £early AptianBarremian

Ch. litterariusto

upper partof

M. bollii

Light gray nanno-limestone interbeddedwith olive-gray marlstone,black shale, and rare chert

(Unit 5a)

EarlyCretaceous

Neocomian

Lower partof

M. bolliito

upper partof

N. colomi

: zi

In sider.layer(3.68)(1.60)

In turb.layer

2.34

3.31

3.14-2.50

4.442.86

Figure 12. (Continued).

185


CORESDEPTH

(m)

LITHOLOGY

BIOSTRATIGRAPHIC ZONATION

FORAMINIFER NANNOPLANKTON RADIOLARIANS

z o3 OO ->

>


1050

1100

1150

1024.5

1034

1053

— -1062.5

-1081.5

-1091

-1105.5-1111

-1119.5

-1127.5

-1135

-1142.1148-11511153T. D.

1200

2 4 | 6 8 10 12

Light gray nanno-limestone interbeddedwith olive-gray marlstone,black shale, and rare chert

(Unit 5b)

P. embergeri

Reddish brown nanno-bearing argillaceouslimestone, marl, clay-stone, and chert

(Unit 6)

LateJurassic

LateJurassic

E

3.78

3.444.753.21

4.203.102.56

4.26

Basalt(Unit 7)

Figure 12. (Continued).

values obtained are not considered very reliable(Duncan and Jackson, this volume).

If the basalt encountered at this site is a sill, then itmust have either been intruded sometime in the LateJurassic, hence it would be almost as old as the regionalbasement, or younger but intruded near the basement-sediment interface. Both petrological and post-cruiseseismic profiling strongly support the interpretation ofthe basalt sampled at this site as representing the top ofthe oceanic crust (layer 2) that was formed on the ridgecrest in Jurassic times.

Jurassic-Neocomian CarbonatesThe basal carbonate sequence consists of two

successive units—Oxfordian-Kimmeridgian red argilla-ceous limestones and alternations of dark gray, finelylaminated marls and light gray burrowed limestones ofTithonian-Neocomian age. They represent a pelagicdeposit in a basin situated above the CCD. The waterdepth is considered to increase regularly from bottomto top, but even at the base of the section the sedimentsindicate deep-water deposition. The fossils found inthese layers are predominantly pelagic (planktonic andnektonic) and benthic faunas are rare (benthicforaminifers only). The most striking fossils, besides theclassical assemblages of planktonic foraminifers,coccoliths, and radiolarians, are the ammonoidea(numerous aptychi and some ammonites), and, in thereddish brown layers, pelagic lamellibranchiates andpelagic echinoids (Saccocoma). Abundant bioturba-tion indicates a well-oxygenated environment. Theselayers are almost identical to layers of the same agesampled during Leg 11 at Sites 99, 101, and especially

Site 105. The similarities can be observed even inminute details of the sedimentary structures (Lancelotet al., 1972). The only differences are both the lesseramount of redeposition structures (turbidites andslumping) and the greater amounts of chert at Site 367.The lack of major redeposition features at this siteappears directly related to a much lower reliefenvironment. The relative abundance of chert mightresult in differences in surface water productivity due todifferent water circulation patterns over both basins.These sediments are very similar to the "AmmoniticoRosso," "Marne a Fucoide," and Maiolica facies of theTethys realm from the Dinarides and Alps to theSubbetic and North African geosynclines (seediscussion in Jansa et al., this volume; Bernoulli, 1972).This confirms the existence of good communicationbetween the young Atlantic and Tethys in the LateJurassic and Early Cretaceous. More regionally, theNeocomian part of the section compares extremely wellwith the sediments of the same age outcropping onMaio Island (Cape Verde islands) and described byStahlecker (1934).

Barremian-Early Aptian Variegated Claystone

This facies, recovered in only one core (Core 24),which occurs between interbedded dark and light graylimestone and black clay, was not found in the westernNorth American basin. At Site 105 a gradual transitioncan be directly observed, through continuous coring,between the limestones and the overlying black clays.The dark marly interbeds in the limestones aregradually thicker and darker toward the upper limit ofthe limestone facies until the limestone beds disappear

186


completely in the black shale facies. Such a transitioncan be interpreted as the gradual onset of poorlyoxygenated conditions in the basin. Here, at Site 367,the occurrence of carbonate-free variegated red andgreen claystones between the limestones and the blackshales mark an interruption in the gradual increase ofreducing conditions. This could result from a regionaltemporary bottom circulation in the eastern basin. Theoccurrence of relatively well-oxygenated, deep-sea clayat that level is interesting as it provides some indicationabout the time at which the floor of the basin crossedthe level of the CCD. This cannot be observed in thewestern basin because the black clays are very poorwater depth indicators. Such facies are found today inevery range of water depth, even on continental shelvesor in epicontinental seas whenever the oxygenation onthe bottom is relatively poor. The presence ofvariegated, carbonate-free clays at the base of the blackclays would indicate that unless the CCD deepeneddrastically during the Aptian-Albian times, the latterfacies was deposited below the CCD, probably in arelatively deep basin.

Late Aptian-Cenomanian Black Shale

This facies, similar in age and composition to the onesampled in the North American Basin, shows typicalfeatures of reducing environments. Particularlycharacteristic are the abundances of organic matter (upto 6.7% of organic carbon), the occurrences of typicalauthigenic minerals such as dolomite and possiblysiderite and abundant pyrite, and the abundance ofnatural gas (methane). The significance of reducingenvironments in deep-sea basins is not entirely clear.The reducing conditions can occur either at or abovethe water-sediment interface or within the sediments. Inthe first case, the simplest explanation is a more or lessstagnant environment in the basin or a well layeredcirculation which does not bring oxygenated waters tothe bottom (Black Sea type). In the second case, if thebottom waters are oxygenated, then one must invoke avery steady and high input of organic matter in thesediment to avoid oxidation at, or very close to, the seabottom (see Gardner et al., this volume). Of course anintermediate case is also possible. In the case of theblack shales of both the western and eastern NorthAtlantic basins several indications point toward at leasta reduced bottom circulation, although the occurrenceof occasional burrows in the sediments shows that theenvironment was probably not completely anoxic,hence not completely stagnant. The rate of accumula-tion does not exceed 20 mm/1000 yr (not corrected forcompaction) and such a value does not seem highenough to explain reducing conditions maintainedwithin the sediments if the overlying waters are welloxygenated. For example, on the Blake-Bahamas outerridge, reducing conditions are maintained within thesediments, although the bottom is permanently sweptby currents, but there the rates of accumulation reachvalues as high as 190 mm/1000 yr (Ewing and Hollister,1972). Furthermore, the very wide distribution ofreducing environments in the deep North and SouthAtlantic basins, covering a wide range of latitudes,during the Early Cretaceous and to a lesser extent

during the Late Cretaceous, suggests that the possiblerestriction of bottom circulation during these timesmight be a more determinant factor than excessiveinput of organic matter in the basins. Geochemicalstudies found elsewhere in this volume examine ingreater detail the origin of the organic matter.

Late Cretaceous-Early Tertiary (?Paleocene)Multicolored Silty Clay

These sediments are mainly of terrigenous origin anddeposited below the CCD. Their silt content isrelatively low and they reflect mainly a distalterrigenous facies. Comparison with the thickterrigenous accumulation found under the continentalshelf and in the Senegal Basin suggests that only a smallfraction of the terrigenous output reached the basin andthat most of it was trapped in the subsiding continentalshelf areas. The same observation can be made on thewestern side of the Atlantic where Cretaceousterrigenous deposits make up a very large part of thethick layers underlying the continental shelf off CapeHatteras whereas the Upper Cretaceous sediments inthe North American Basin appear extremely reduced oreven maybe entirely missing.

Although these sediments at Site 367 are described asmulticolored, they do not reflect the same metal-enriched zeolitic environments as at Site 105. Thisdifference might be interpreted as resulting from lesservolcanic activity in the eastern basin during the LateCretaceous. It might also indicate that the barren,multicolored, highly zeolitic clay of Site 105 could be ofearly Tertiary age and could correlate with the earlyand middle Eocene zeolitic clays of Site 367. Strongbottom current circulation would have either greatlyreduced deposition of Late Cretaceous sediments oreroded most of them in the North Atlantic Basin.

The presence in these layers of assemblages ofagglutinated foraminifers bearing a very strongresemblance with those found in the Alpine flysch ofthe same age is interesting.

Eocene Siliceous and Zeolitic ClaysThe Eocene is characterized by a worldwide high

content in silica. This silica is either in the form ofradiolarian tests or recrystallized in chert nodules andporcellanitic beds. Both lithologies are found hereassociated with zeolitic clays and it is tempting to relatethe increased input of silica in the ocean with a phase ofvolcanic activity. However, comparison with thewestern North Atlantic where no chert or radiolarianswere found associated within the highly zeoliticsediments shows that other factors might be equallyimportant in the sudden "radiolarian bloom"commonly observed in the world ocean during the earlyTertiary. The absence of chert at Site 105 might also becaused by sampling gaps.

The Eocene sediments show alternations of blackand green clay in which the organic carbon contentvaries from 2.5% to 0.3%, respectively. This cyclic(decimeter-scale) sedimentation might reflect variationsin the input of terrigenous sediments or cyclicvariations in the bottom current circulation (see Deanet al., this volume).

187


Post-Eocene Nannofossil Marl and Silty ClayThis section has been only partially sampled and the

stratigraphic control toward the base of the interval isnot well established. It appears, however, that theunsampled pre-middle Miocene section is greatlyreduced in thickness. This might reflect the presence ofhiatuses or at least very condensed sections in the lowerMiocene and Oligocene sediments.

The two main characteristics of these sediments arethe increase in terrigenous, often coarse-grained,material and the relative abundance of calcareousmicrofossils. The terrigenous input increases regularlyupward in the section, and the Pliocene and Quaternarysediments, with accumulation rates up to 90 m/m.y.,contain sand and silt beds deposited by turbiditycurrents. Other evidences of redeposition of material ofshallow-water origin are also provided by theoccurrence of reworked microfossils of Mesozoic andCenozoic age in these layers. Such evidences ofdownslope transportation are in good agreement withthe physiographic situation of Site 367 (see Figure 1).The lower continental rise off southern Senegal andGuinea is crossed by several channels that probablyhave played a major role in building the lowercontinental rise since at least the Pliocene and possiblysince the upper Miocene, by collecting and spreadingthe terrigenous material brought downslope throughthe numerous incisions visible on the adjacentcontinental slope.

Sedimentological Problems

Cyclic Sedimentation = Dilution Versus Dissolution;Role of Diagenesis

Cyclic sedimentation was encountered at this site. Amore detailed report on this problem is found in Deanet al., this volume. In general the cycles correspond toalternations of terrigenous-rich/biogenous-poor andterrigenous-poor/biogenous-rich beds. It is difficult todetermine which part of the cyclicity is due to variationin the input of terrigenous material and which part isdue to dissolution of the calcareous material.Furthermore, it is difficult to assess, in the case ofdissolution, if the dissolution occurred at or very nearthe sea floor or if it occurred after burial and wascaused by diagenesis. Other cycles, such as the colorbanding observed in the Eocene green and black claysor in the variegated red and green Barremianclaystones, might result from diagenetic changes of theredox potential within the sediments. Such changesmight be influenced by the primary composition of thesediments which, in turn, might result from environ-mental conditions such as input or bottom watercirculation. There are some cases, however, where itappears possible to make a distinction between dilutionand dissolution cycles. Dilution cycles, for example, aresuspected when the terrigenous-rich layers containrelatively abundant, well-preserved microfossilsdispersed in clay layers, whereas in dissolution cycleseither the clays are barren or they contain rare and verypoorly preserved faunas. The cycles observed in theNeocomian-Tithonian dark gray-light gray limestones,for example, appear to be dilution cycles.

Diagenesis and Lithification

This hole offers a good opportunity to studydiagenetical lithification of both carbonate andnoncarbonate rocks under relatively high overburdenloads.

The carbonate rocks display the classical stages oflithification observed at several previous DSDP sites:overgrowth on coccoliths begins at about 300 meterssubbottom. At about 900 meters actual cementation(micritization) occurs and the first real limestonesappear. In these limestones the degree of cementation isaffected directly by the clay content of the sediments, ascan be observed easily near the base of the sedimentarysection where dark marl is always softer than whitelimestone. The same observation was made at Site 105(Lancelot et al., 1972), but here at Site 367, because of athicker overburden, the phenomenon is even morestriking and the light gray, almost pure limestone isvery hard and almost completely recrystallized. Thefirst styloliths appear in limestone at about 1050meters. This had been rarely observed in Deep SeaDrilling samples until now.

The clays simply lose their water under high pressurecaused by overburden. They remain plastic until about650 meters subbottom, then they gradually becomefissile and shaly. Even below 1150 meters they stillretain some plasticity.

REFERENCES

Barnard, T. and Hay, W.W., 1974. On Jurassic coccoliths: atentative zonation of the Jurassic of southern England andnorth France: Eclog. Geol. Helv., v. 67, p. 563-585.

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.

Bernoulli, D., 1972. North Atlantic and MediterraneanMesozoic facies: a comparison. In Hollister, CD., Ewing,J.I., et al., Initial Reports of the Deep Sea Drilling Project,Volume 11: Washington (U.S. Government PrintingOffice), p. 801-871.

Bukry, D. and Bramlette, M.N., 1969. Coccolith agedeterminations—Leg 1, DSDP. In Ewing, M., Worzel,J.L., et al., Initial Reports of the Deep Sea DrillingProject, Volume 1: Washington (U.S. GovernmentPrinting Office), p. 369-387.

Burckhardt, C, 1906. La faune jurassique de Mazapil: Bol.Inst. Geol. Mexico, v. 23.

, 1912. Faunes jurassiques et cretaciques de SanPedro del Gallo: Bol. Inst. Geol. Mexico, v. 29.

, 1919. Faunes jurassiques de Symon: Bol. Inst.Geol. Mexico, v. 33.

Ewing, J.I. and Hollister, CD., 1972. Regional aspects ofdeep sea drilling in the western North Atlantic. InHollister, CD., Ewing, J.I., et al., Initial Reports of theDeep Sea Drilling Project, Volume 11: Washington (U.S.Government Printing Office), p. 951-973.

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

Hayes, D.E. and Rabinowitz, P.D., 1975. Mesozoic magneticlineations and the magnetic quiet zone off northwestAfrica: Earth Planet. Sci. Lett., v. 28, p. 105-115.

Hollister, CD., Ewing, J.I., et al., 1972. Initial Reports of theDeep Sea Drilling Project, Volume 11: Washington (U.S.Government Printing Office), p. 1077.

188


Jacobi, R. and Hayes, D.E., in preparation. Bathymetry andmicrophysiography of the continental margin offnorthwest Africa.

Lancelot, Y., Hathaway, J.C., and Hollister, CD., 1972.Lithology of sediments from the western North Atlan-tic—Leg 11, Deep Sea Drilling Project. In Hollister, CD.,Ewing, J.I., et al., Initial Reports of the Deep Sea DrillingProject, Volume 11: Washington (U.S. GovernmentPrinting Office), p. 901-949.

Larson, R.L. and Pitman, W.C., III, 1972. World-widecorrelation of Mesozoic magnetic anomalies, and itsimplications: Geol. Soc. Am. Bull., v. 83, p. 3645-3662.

Luterbacher, H., 1972. Paleocene and Eocene planktonicforaminifera, Leg XI, Deep Sea Drilling Project. InHollister, CD., Ewing, J.I., et al., Initial Reports of theDeep Sea Drilling Project, Volume 11: Washington (U.S.Government Printing Office), p. 547-550.

Stahlecker, R., 1934. Neocom auf der Kapverden-Insel Maio:Neuen Jb. Mineral., Beil.-Bd. 73, Abt. B, p. 265-301.

, 1935. Neocom auf der Kapverden-Insel Maio: N.Jb. Min. Geol. Pal., v. 73, p. 265-301.

Thierstein, H.R., 1971. Tentative Lower Cretaceouscalcareous nannoplankton zonation: Eclog. Geol. Helvv. 64, p. 459-488.

van Hinte, J.E., 1972. The Cretaceous time scale and plank-tonic foraminiferal zones: Koninkl. Nederl. Akad.Vanwetenschappen, v. 75, p. 8.

, 1976. A Jurassic time scale: Am. Assoc. PetrolGeol. Bull., v. 60, p. 489-497.

von Rad, U. and Rosch, H., 1972. Mineralogy and origin ofclay minerals, silica, and authigenic silicates in Leg 14sediments. In Hayes, D.E., Pimm, A.C., et al., InitialReports of the Deep Sea Drilling Project, Volume 14:Washington (U.S. Government Printing Office), p. 727-751.

Wilcoxon, J.A., 1972. Upper Jurassic-Lower Cretaceouscalcareous nannoplankton from the western NorthAtlantic Basin. In Hollister, CD., Ewing, J.I., et al., InitialReports of the Deep Sea Drilling Project, Volume 11:Washington (U.S. Government Printing Office), p. 427-457.

APPENDIX A: GEOLOGICAL PROBLEMSOF THE UPPERMOST 8 METERS AT DSDP SITE 367

L. Diester-Haass, F.C. Kögler, and E. Seibold,Geologisch-Palaontologisches Institut der Universitat Kiel,

Olshausenstr. 40/60, 23 Kiel, Federal Republic of Germany

INTRODUCTION

As in most of the DSDP holes, the first core at Site 367 penetratedHolocene and Pleistocene foraminifer-bearing nannofossil marl withsevere drilling disturbances and some voids. Therefore, we decided totake some cores during a post-Leg 41 survey at this location withValdivia in July 1975. We selected a box core of practicallyundisturbed material (cross-section 30 X 30 cm, length 8.10 m) taken20°02.74'W (Valdivia-X0-13209-2) to investigate the uppermost 8meters of the sediment column. Some physical properties weredetermined (roughly every 50 cm) onboard immediately after the corewas taken (Figure Al). Additional physical properties werecompleted in our shore laboratories. Quantitative coarse-grainanalyses were made at 10 cm intervals. The shipboard coredescription shows the core is highly bioturbated with no indicationsof turbidites. Grain-size analysis (Figure Al, n) shows the coreconsists of clay (20% to 40%), silt (50% to 80%), and sometimes sand(15% to 20%).

The stratigraphic zonation (Figure Ala) is based on the presence ofabundant Globorotalia menardii (Ericson and Wollin, 1968) and G.tumida and on CaCθ3 content (Figure All). The CaCCb curves fromabout the same region (Gardner, 1975) show exactly the same trendas that of core 13209. The cores investigated by Gardner (1975) also

have biostratigraphical control, therefore, it is possible to correlatethe carbonate minima units in core 13209-2 to glacial periods (Y andW zones) and the carbonate highs to interglacial periods (Z and Xzones). Some of the peaks in Figure A1 ("physical properties," c-i) donot correspond to peaks and boundaries in Figure A1 (a, 1-u) becausephysical properties were determined in 13-cm slices. Only the upperboundaries of these slices are indicated in Figure Al.

COMPARISON WITH NEARBY CORES

Echo-sounder profiles from the area and sketch maps of thebathymetry of Cape Verde region indicate channels probably relatedto turbidity current activities. Lithologic Unit 1 of the sequence coredat Site 367 contains many turbidites. Therefore, at 12°29.28'N,20°04.21'W, we took other cores in 4743-4753 meters (corrected)water depth (Station Valdivia 10-13208) and their examinationrevealed turbidites with coarse-grained quartz sands in the uppermostparts below about 40 cm depth. This contrasts with thepredominately clayey silt facies found in core Va 10-13209-2. Theparameters described by Rupke et al. (1974) for fine-tail turbiditescould not be found in core Va 13209-2, which may be due partly tostrong carbonate dissolution and partly to the methods we have used.

PHYSICAL PROPERTIES AND SEDIMENTATION

Values of shear strength (10 to 20 g/cm2) of the remolded materialare low (see Richards, 1961, 1962). The maximum (29.1 g/cm2)corresponds with the carbonate-rich foraminifer ooze at 263 to 276cm core depth (Figure Al, c). Bulk densities of 1.13 to 1.42 g/cm3

(Figure Al, f) yield overburden pressures of only about 200 g/cm2 at8 meters of depth. Bulk and dry density variations (2.50 to 2.65g/cm3) correlate with carbonate contents. Variations in natural watercontent (Figure Al, i) are dependent on many factors. It showsroughly a negative correlation with carbonate contents so we assumethat most of the Globigerina tests are filled with sediment and notwith interstitial water (see Einsele and Werner, 1968). Differentcomposition and degree of bioturbation may have some influence. Ingeneral, water content is somewhat higher in the finer grainedsections (Figure Al, a: Y, W zones). Relatively high colloidalactivities (Figure Al, g, 0.99 to 2.60) indicate active clay fractions inmost of the samples (Skempton, 1953), with montmorillonite animportant clay mineral. The ratios of shear strength to overburdenpressure decrease more or less continuously. Therefore, a normalconsolidation without accentuated hiatuses is probable (Figure Al,h).

TABLE A1Shipboard Core Description Va 10-13209-2

0-5 Surface layer, technical disturbances

5-18 Foraminifer ooze, brownish, bioturbated, burrowsmostly horizontal, diameters up to 1.5 cm, sometimesopen

18-30 Clayey silt

30-46 Clayey silt, brownish gray, bioturbated

46-54 Clayey silt, brownish, bioturbated, burrows elliptical, upto 4 x 1.5 cm, filling is dark gray

54-150 Clayey silt, dark gray, bioturbated, burrows mostly

horizontal, diameters up to 5 cm, fecal pellets abundant

150-192 Clayey silt, dark gray, few burrows and fecal pellets

192-291 Foraminifer ooze, light gray, bioturbated

291-295 Foraminifer oooze, light gray303-380 Clayey silt, dark gray-brown, with bottle-like dark gray

features

380-383 Greenish layer

383-505 Clayey silt, dark gray-dark brown, partly lighter coloredlayers, with bottle-like dark gray features

505-788 Clayey silt-foraminifer ooze, light gray with dark grayparts

Greenish layers at 88-90, 279, 295, 303, 310, 322, 329,380-383,688 cm

189


CORE 13209-2shear strength Igcm"2! bulk dry activity c /p -ratio nat.wat.cont. accum. rate CaCU3 grain size distribution

rem overb.pressurelgcm2] dens.igcm3! 1 3 2 U 6 8 100 1607. CaCC^insol. 20 607. 5 157.

PHYSICAL PROPERTIES

CORE 13209-2

terrigenous mat. desert quartz n. glauconite min>125/um40 807. 20 607. 1 27. 1 2°/. 20

50 307. wh.t. 100 907. pl.f607. pl.f. 50 707. frag. 0 107. benthf.

Figure Al. Analytical results from Core Va 13209-2 fValdvia cruise 10-1975) from Site 367 (a) foraminiferal zones, basedon the presence of Globorotalia menardii (tumida) and on amounts ofCaCOj (for explanation see text); (b) depth be-low surface in cm; (c) shear strength (in the remolded state) in 9/cm2; (d) overburden pressure g/cmz; (e) shear

190


strength in the natural state in gjcm? (min. and max. values from 3 to 8 determinations on 13 ×13 cm surfaces from thecentral part of the 30 X 30 cm cross-section; (f) bulk and dry density (dens.) in glcmr; (g) activity; (h) C/p ratios (ave-rage of natural shear strength divided by overburden pressure; (i) Natural water content (nat. wat. cont.) in % water ofdry weight; (k) accumulation rates of calcium carbonate and total insoluble material (insol.) in cm/lO^yr. Absoluteages for calculation of these rates are taken from Sancetta et al, 1973; (I) Weight percent CaCO^ of total sediment; (m)weight percent organic carbon (C O /J of total sediment: (n) grain size distribution: % sand (>63 µm) and % 40 to 63 µmfraction. Right side: % clay, percents of total sediment; (o) amount of terrigenous material in % of 40 to 63 µm and in% of >63 µm fractions; (p) desert quartz numbers (ratio of red-stained quartz to colorless quartz) X 100. Open circlesindicate presence of wood fibers; (q) amount of glauconite in % of 40 to 63 µm and in % of >63 µm fractions; (r)amount of minerals (min.) >125 µm in % of the sand fraction; (s) amount of planktonic foraminifers (plf.)in the sandfraction; (t) fragmentation of planktonic foraminifers calculated as (ratio of fragments to whole tests + fragments) ×100. wh.t. - whole tests, frag. = fragments; (u) ratio of benthic to planktonic foraminifers calculated as (benthic fora-minifers/benthic + planktonic foraminifers) X 100. Benth.f. = benthic, pl.f. = planktonic foraminifers.

Natural shear strengths (Figure Al, a) generally increase withdepth, together with overburden pressure. The differences betweenminimal and maximal values are due to zones with different degreeand types of bioturbation and infilling of burrows. The slope of theshear-strength curves may be divided into three parts: 0 to 300 cm and300 to 530 cm show steep slopes which decrease towards the base.Below 530 meters there seems to be no trend. The maximal values atthe bases correspond with different materials; mainly highercarbonate, sand, and foraminifer contents. Nevertheless, there alsoseems to be a general relationship between sediment thickness andnatural shear strength (Figure A2). Shear strength increases slowerwith depth in regions with high accumulation rates than in regionswith lower accumulation rates. Data from core Va 13209-2 arecompared with a core from the deeper Gulf of Oman containingturbidites and other cores from regions with higher accumulationrates (Figure A2).

The different slopes in Figure Al, e, may also be related to thedifferent accumulation rates (Figure Al, k). The rate of accumu-lation in the Y zone is 2.87 cm/103 yr and that for the W zone is 6.45cm/103 yr.

CLIMATE AND DISSOLUTION

The amount of terrigenous material in the >40µm fraction (FigureAl, o), the amount of desert quartz (Figure Al, p), the presence ofwood fibers (Figure Al, p) which were probably transported byrivers, and the amount of minerals in the > 125 µm fraction (FigureAl, r) can be interpreted in terms of paleoclimate (for details seeDiester-Haass, this volume).

The amount of terrigenous material in the coarse fractions in theinterglacial Z and X zones is low, desert quartz numbers are high, nowood fibers and almost no minerals > 125 µm in size are present.These sediments reflect the influence of a desert environment withlow supply of fluviatile material.

The opposite is found during the glacial periods W and Y zones.Very high amounts of terrigenous material in the >40 µm fraction areseen (up to >90% in the 40-63 µm fraction), desert quartz numbersare very small (<20), and wood fibers occur as well as minerals > 125µm in size. This all suggests a reduced influence from deserts.Addition of fluviatile material at these times is probable as shown bythe presence of wood fibers (Sarnthein, 1971) and by the coarseminerals. The maximum size of quartz being transported insuspension by wind is about 80 µm (Bagnold, 1954) so the minerals> 125 µm is size have been transported by an agent with highertransport capacity.

The alternation of sediment reflecting desert influence in inter-glacial periods and units reflecting fluviatile input during glacialperiods is explained in the following way. When sea level was high,the river-borne material transported by the Gambia River did notreach Site 367 because most of the material was captured on the shelf.Only the influence of the northeast trade winds blowing from theSahara is obvious at the site, a region situated in the zone of mostfrequent dust fall occurrence (Folger, 1970).

During the glacial W and Y zones, sea level was at least 100 meterslower than during interglacial periods and fluviatile material wastransported by rivers to the shelf-break region where it could bereworked and transported in suspension by turbidity currents to thearea of Site 367. Accumulation rates of terrigenous components >63µm in size increase from 0.0012 cm/103 yr—Z Zone (0.0003 cm/103

yr—X Zone) to 0.0033 cm/103 yr—Y Zone (0.012 cm/103 yr—WZone). Consequently, the high amounts of terrigenous material in theglacial sections are not simply the result of increased dissolutionduring glacial periods.

The presence of glauconite (Figure Al, q) and phosphorite grainsin the glacial sections indicates shallow water conditions (loweredsea-level) (Diester-Haass, this volume). The low or disappearingdesert influence during glacial periods is surprising because the aridzone with red dunes shifted as far south as about 14°N (Michel,1973). The more easterly component of the glacial trade winds(Sarnthein and Walger, 1974; Diester-Haass, 1976) is probablyresponsible for the reduced or disappearing desert influence in thearea of Site 367.

The degree of carbonate dissolution can be derived from theamount of planktonic foraminifers in the coarse fractions (Figure A1,s), the fragmentation of planktonic foraminifers (Figure Al, t) (fordetails see Diester-Haass, this volume), and the ratio of planktonic tobenthic foraminifers (Figure Al, u). Carbonate dissolution wasminimal during interglacial periods, as shown by planktonicforaminifer percentages in the sand fraction up to 99%, frag-mentation values of 42% to 80%, and low ratios of benthic toplanktonic foraminifers. Glacial periods witnessed a strong increasein dissolution which decreased planktonic foraminifers to less than20% and sometimes completely eliminated them from the sediment.Fragmentation increased up to 100% and the ratio of benthic toplanktonic foraminifers increased. The strong dissolution caused thelow sand fraction values of total sediment in glacial periods andconversely weak dissolution allowed higher amounts of sand-sizedcarbonate material (Figure Al, n).

Gardner (1975) explained the intense dissolution in glacial periodsby a rise of the lysocline from about 4500-4750 meters today to 4327-3750 meters in glacial periods due either to an increased influence ofnorthward flowing Antarctic bottom water or to the generation of asouthward flowing North Atlantic deep water.

The repeated change from glacial to interglacial conditions canproduce a cyclic sedimentation of marl (or chalk) and clay as shown

1.0 Cores from:

123456789

101112

T3)

Central PacificArabic SeaNorthern PacificEastern PacificWestern Baltic SeaGulf of MexicoCentral PacificGulf of OmanGulf of MexicoCentral PacificCentral PacificMississippi DeltaEast Atlantic Site 367

. . 4

4 6Sediment thickness (m)

Figure A2. General relations between overburden pressureand shear strength (Kögler, 1974).

191


by the contents of calcium carbonate (Figure Al, 1) by: (a) fluctua-tions in dissolution; (b) an increase in dilution by terrigenous input(Dean et al., this volume). The accumulation rates of total insolubleterrigenous material increase by a factor of 3 (and 6, taking intoaccount the increased turbidity current influence in the W Zone,Figure Al, k) in glacial periods compared to interglacial ones.

Organic matter content (Figure Al, m) does not seem to be directlyrelated to contents of clay (Figure Al, n) or wood fibers (Figure Al,p) or dissolution effects, but does seem to correlate with dilution byterrigenous material. Fluctuations in productivity cannot be assessedwith our data.

ACKNOWLEDGMENTS

We thank Master Papenhagen and the crew of Valdivia, Dr.Ackermand (phosphorite determinations), Dr. Müller (calciumcarbonate determinations), J. German and N. Mühlhan (physicalproperties determination), B. Alberts and A. Rongitsch (samplepreparation), and M. Whiticar (English).

The financial supports of the Deutsche Forschungsgemein-schaft/Bundesministerium für Forschung und Technologie are grate-fully acknowledged.

REFERENCES

Bagnold, R.A., 1954. The physics of blown sand and desert dunes:London (Methuen and Co., Ltd.).

Diester-Haass, L., 1976. Late Quaternary climatic variations inNorth-West Africa deduced from East Atlantic sediment cores:Quat. Res., v. 6, p. 299-314.

Einsele, G. and Werner, F., 1968. Zusammensetzung, Gefüge undmechanische Eigenschaften rezenter Sedimente vom Nildelta,Roten Meer und Golf von Aden: Meteor Forsch. Ergebn., C,v. 1, p. 21-42.

Ericson, D.B. and Wollin, G., 1968. Pleistocene climates andchronology in deep-sea sediments: Science, v. 162, p. 1227-1234.

Folger, D.W., 1970. Wind transport of land derived mineral, biogenicand industrial matter over the North Atlantic: Deep-Sea Res.,v. 17, p. 337-352.

Gardner, J. V., 1975. Late Pleistocene carbonate dissolution cycles inthe eastern equatorial Atlantic. In Dissolution of Deep-SeaCarbonates, Spec. Publ. 13, Cushman Found. Foram. Res.,p. 129-141.

Kögler, F.C., 1963. Das Kastenlot: Meyniana, v. 13, p. 1-7." 1974. Sediment-physical properties of three deep-sea cores

from the Central Pacific Ocean: Meerestechnik mt, v. 5, 6,p. 199-201.

Michel, P., 1973. Les bassins des fleuves Senegal et Gambie. Etudegéomorphologique: Mém. ORSTOM, No. 63, Paris.

Richards, A.F., 1961. Investigations of deep-sea sediment cores.1. Shear strength, bearing capacity and consolidation: U.S. NavyHydrographic Office, Tech. Rept. 63, p. 1-70.

, 1962. Investigations of deep-sea sediment cores. 2. Massphysical properties: U.S. Hydrographic Office, Tech. Rept. 106,p. 1-145.

Rupke, N.A., Stanley, D.J., and Stuckenrath, R., 1974. LateQuaternary rates of abyssal mud deposition in the westernMediterranean Sea: Mar. Geol., v. 17, p. M9-M16.

Sancetta, O., Imbrie, J., and Kipp, N.G., 1973. Climatic record of thepast 130,000 years in North Atlantic deep-sea core V 23-82:correlation with the terrestrial record: Quat. Res., v. 3, p. 110-116.

Sarnthein, M., 1971. Oberflachensedimente im Persischen Golf undGolf von Oman. II Quantitative Komponentenanalyse der Grob-fraktion: Meteor Forsch. Ergebn., C, v. 5, p. 1-113.

Sarnthein, M. and Walger, E., 1974. Der àolische Sandstrom aus derWest-Sahara zur Atlantikküste: Geol. Rundschau, v. 63,p. 1065-1087.

Skempton, A.W., 1953. The colloidal activity of clays: ThirdInternat. Conference of Soil Mechanics and FoundationEngineering, v. 1, p. 57-61, Zurich.

192


* = minor lithology K E Y R A R E < 5

SMEAR SLIDE SUMMARY SITF 367 Page _ L _ o f _ ? _ ABUNDANT 25-" 75 • LDOMINANT 75-100 i • • •

HOLE EXOGENIC | AUTHIGENIC-DIAGENETIC . I . . . B I 0 G E N | C

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* = minor lithology K E y R A R E < 5 % •

SMEAR SLIDE SUMMARY SITF 367 Page _ i _ o f _ ? _ ABUNDANT 2I - f l ^ • .DOMINANT 75-100 ^ ^ •

H O L E ~ E X O G E N I C | A U T H I G E N I C - D I A G E N E T I C I . . . B I 0 G E N I C

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Site 367 Hole Core 1 Cored Interval: 0.0-8.0 m Site 367 Hole Core 2 Cored Interval : 8.0-17.5 m

LITHOLOGIC DESCRIPTION

10YR 5/2

10YR 5/2

NANNO MARL with various biogenictions.

composi-

NANNO MARL, moderate yellowish brown (10YR5/2) with mixed grayish brown (2.5Y 5/2),and dark greenish gray (5GY 4/1) in Section5, soft, intense drilling disturbance.

At 4-0 to 40 cm FORAM-BEARING NANNO MARL,medium light gray (N5), soft, intensedrilling disturbance.

At 5-75 to 77 cm SILTY NANNO MARL, darkgreenish gray (5GY 4/1), soft, intensedrilling disturbance, Mn stains at uppercontact.

Minor flame feature, formed by drillingdisturbance at 6-100 to 115 is a FORAM-BEARING NANNO OOZE.

SS at 1-120 (dominant lithology)QuartzHeavy mClayForamsNannos

ineralsR•:ACA

DiatomsRadsSponge spiculesFish debris

:C-R

SS at 2-65 (dominant lithology)Quartz C NannosFeldspar R DiatomsClay A Rads

SS at 4-20 (minor lithology)Quartz R NannosClay" A DiatomsForams C

SS at 5-75 (minor lithology)Quartz C Nannos AHeavy minerals R Diatoms RClay A Rads RCarbonate . Sponge spicules R

unspecified R

SS at 6-110 (minor l i tho logy)Quartz R Diatoms RForams C Rads RNannos D Sponge spicules R

SS at CCQuartz R Forams RKspar R Nannos CHeavy minerals C Rads RClay A Sponge spicules RGlauconite R

Carbonate Bomb: 5-49 to 50 cm = 41%

CARBON-CARBONATE3-44 (3.3-0.7-22)5-53 (4.8-0.2-38)

GRAIN SIZE3-42 (7.4-37.8-54.8) Silty clay5-50 (9.7-45.3-45.0) Clayey silt


10YR 4/1

NANNO MARL AND NANNO-BEARING SILTY CLAY.

NANNO MARL, dark gray (N3), soft, intensed r i l l i n g disturbance, with foram-bearingnanno marl in Section 2, dark gray (10YR4/1) , sof t .

At 3-122 to 125 cm SILTY CLAY, dark greenishgray (5GY 3/1), s t i f f .

Sections 4 thru 6, NANNO-BEARING SILTY CLAY,medium dark gray (N4), s t i f f , severe d r i l l -ing disturbance, with th in zones of verybadly disturbed yellowish brown (1OYR 5/2).

SS at 1-80 (dominant l i thology)Quartz R GlauconiteKspar R NannosHeavy minerals R RadsClay A Sponge spicules

SS at 2-60 (minor l i thology)Quartz R NannosHeavy minerals R DiatomsCarbonate Sponge spicult

unspecified R Forams

SS at 4-60 (dominant l i thology)

Carbonate Bomb: 2-63 to 64 cm • 42%


GRAIN SIZE2-67 (3.9-29.9-66.3) Silty clay5-84 (1.3-44.1-54.6) Silty clay

QuartzKsparMicaHeavy mineralsClay

SS at 2-CCQuartzMicaHeavy mineralsClav

CRRRD

RRRA

GlauconiteCarbonate

unspecifiedNannosSponge spiculesFish debris

Fe/MnForamsNannosRads

R

RCRR

RRAR

Explanatory notes in Chapter 1

Site 367 Hole Core 3 Cored Interval : 54.0-63.5 m Site 367 Hole Core 4 Cored Interval : 63.5-73.0


10YR 6/1

BADLY DISTURBED NANNO CLAYEY SAND.

NANNO CLAYEY SAND, dark yellowish brown(10YR 5/2), soupy, medium-sized sandgrains, abundant quartz.

At 1-7 to 32 cm, FORAM-BEARING NANNO MARL,greenish gray (5GY 6/1), stiff, severedrilling disturbance, possible burrows ormottling. Lumps of grayish blue green clay(5BG 5/2) occur at 1-100, 2-12, and 2-37 to42.

SS at 1-22 (minor lithology)Quartz R Nannos. AClay A Diatoms RForams C

SS at 1-81 (dominant lithology)Quartz A ForamsFeldspar R NannosHeavy minerals R RadsClay A

SS at 1-107 (minor lithology)Clay D Calcite rhombsPyrite R

SS at CCHeavy minerals R NannosClay A DiatomsForams C Rads

CARBON-CARBONATE2-83 (2.5-0.1-20)

GRAIN SIZE2-84 (57.4-12.2-30.4) Clayey sand


10YR 4/1

2.5Y 6/1

5G 4/1

2.5Y 6/1

INTERBEDDED NANNO MARL AND CLAYEY SAND.

NANNO MARL, silt and foram-bearing in somesamples, dark yellow brown (10YR 4/1) inupper part grading to light brownish gray(2.5Y 6/2) in Section 2, stiff, severe tomoderate drilling disturbance, interbedsof FORAM-BEARING NANNO CLAYEY SAND, medium-grain size.

Mn stains and flecks concentrated from2-58 to 65 and 2-86 to 95 cm.

Gradational color boundary at 3-70 betweenoverlying and underlying nanno marls.

SS at 1-10 (minor lithology)Quartz R NannosClay A Diatoms

SS at 1-62 (minor lithology)Quartz A NannosClay A DiatomsForams C Fish debris

SS at 2-30 (dominant lithology)Quartz R NannosHeavy minerals R DiatomsClay A RadsForams C

SS at 3-28 (dominant lithology)Quartz R NannosHeavy minerals R DiatomsClay A RadsForams A

SS at 3-90 (minor lithology)Quartz R NannosHeavy minerals R Fish debrisClay A

SS at 4-40 (dominant lithology)Quartz R ForamsHeavy minerals R NannosClay A DiatomsCalcite rhombs R Rads

Carbonate Bomb: 2-56 to 57 cm • 69?


GRAIN SIZE2-54 (6.0-38.0-56.1) Sil ty clay5-104 (1.3-23.1-75.5) Clay


Site 367 Hole Core 5 Cored In te rva l : 150.5-160.0 m Site 367 Hole Core 7 Cored Interval :245.5-255.0 m

00

AGE

| ? PLIOCENE

ZONES

FORA

MS

NANN

OS

RADS

Ceratolithus

rugosus NN13

FOSSILCHARACTER

FOSS

IL

F

N

F

R

ABUND.

R

R-C

R

PRES.

P

M

G

SECTION

0

1

METERS

0.5 —

1.0 —

CoreCatcher

LITHOLOGY

V

DEFORMATION

LITHO.SAMPLE

82

138


QUARTZ SAND, pale yellowish brown (10YR6/2), firm, intense drilling disturbance.

Small interbed at 130 to 142 cm of NANNO10YR 6/2 MARL, grayish olive (1OY 4/2), firm, intense

drilling disturbance, Mn stains.

SS at 1-82 (dominant lithology)Quartz D Glauconite R

~* 10Y 4/2 Heavy minerals R Forams R

SS at 1-138 (minor litholoqy)Clay A Forams RNannos A Rads RQuartz R

Site 367 Hole Core 6 Cored Interval : 236.0-245.5 m

FOSSILCHARACTER

CoreCatcher


_, 5GY 4/110YR 4/4

5GY 4/1

NANNO MARL AND SILTY CLAYNANNO MARL, dark greenish gray (5GY 4/1)to (10YR 4/4), stiff, slight drillingdisturbance, Mn streaks, gradationalcolor contact.

SILTY CLAY, dark yellowish brown (10YR 4/4),stiff, slight drilling disturbance, mottled,thin bed from 70 to 96 cm. Gradationalcontact with underlying nanno marl. Lowernanno marl has Mn streaks and laminae andvarious subtle color differences.

CORE CATCHER has 2 pebbles, one a CALCAREOUSSILTSTONE, olive gray (5Y 3/2) and aFERRODOLOMITE, light olive gray (5Y 5/2).

SS at 1-76 (dominant lithology)Quartz C ClayHeavy minerals R Fish debris

SS at 1-117 (Minor l i t ho l ogy )Quartz C ClayHeavy minerals R Glauconite

SS at CCHeavy minerals RClay A

GlauconiteNannos


AGE

ZONES

FORAMS

NANNOS

RADS

-

FOSSILCHARACTER

FOSSIL

N

F

R

ABUND.

R

PRES

.

P

SECT

ION

0

1

METERS

1 1 1

1 1

1 1 1

1 1

1 1

1 1

CoreCatcher

LITHOLOGY

VOID

:—---*- -

DEFORMATION

LITHO.SAMPLE

CC


SILTY CLAY, dark greenish gray(5GY 4/1), stiff, greasy, severedrilling disturbance.

5GY 4/1

Site 367 Hole Cored Interval : 302.5-312.0 m


5GY 6/1

ALTERNATIONS OF DIATOM-BEARING RAD CLAYof greenish gray and black colors.

LITHOLOGY 1:DIATOM-BEARING RAD CLAY, greenish gray(5GY 6/1), very stiff; no drilling dis-turbance, burrowed (some coated with Mn),Mn streaks and zones common.

LITHOLOGY 2:DIATOM-BEARING RAD CLAY, black (Nl), verystiff, no drilling disturbance, ellipticalburrows, (filled with Lith. 1), greasy.

Boundaries between Lith. 1 and 2 are verysharp but lower black above gray is alwayssharper.

Zoophycos and Chondrites burrows present.

SS at 1-46 (minor lithology)Quartz R Rads DDiatoms Sponge spicules R

SS at 1-51 (minor lithology)Quartz R NannosHeavy minerals R DiatomsClay A Rads

SS at 2-80 (dominant lithology)Clay A RadsDiatoms C

SS at 4-65 (dominant lithology)QuartzHeavy mineralsClay

SS at 5-10 (minorQuartzClayNannosDiatoms

SS at CCQuartzClayDiatoms


RCA

liRCRC

RAR

DiatomsRads

thology)RadsSponge spiculesFish debris

RadsSponge spicules

CA

ARR

AR


Site

AGE

EOCENE

367

ZONES

FORAMS

NANNOS

RADS

Hole

FOSSIL

CHARACTER

FOSSIL

F

N

F

R

ABUND.

-

-

PRES.

-

-

Core 9

SECTION

0

1

METERS

1 1 1

1

1 . 0 -

Core

Catcher

Cored Inter

LITHOLOGY

VOID

11

,1

,1

11

11

11

1

1 1

II

11

11

11

11

DEFORMATION

1

1

1

1

1

1

/al :

LITHO.SAMPLE

113

145

cc

331.0-340.5 m


CLAY, greenish gray (5GY 6/1), stiff,moderate drilling disturbance, burrowed.Thin interbed of ZEOLITIC CLAY, black(Nl), greasy, occurs at 143 to 146 cm.

A CHERT fragment occurs at 122 cm.

CHERT, dark greenish gray (5G 4/1).

SS at 113 (dominant lithology),.. Quartz R Clay A

s b Y 0 / l Heavy minerals R Zeolites R

SS at 145 (minor lithology)Quartz R Fe/Mn RClay A Rads RZeolites C Fish debrisf?) R

SS at CCHeavy minerals R Clay CZeoli tes R


Site 367 Hole Core 12 Cored Interval : 359.5-369.0 i


AGE

MIDDLE EOCENE

ZONES

FORAMS

NANNOS

RADS

Theocampe mongolfieri

or Theocotyle cryptocephala

FOSSIL

CHARACTER

FOSSIL

N

F

R

ABUND.

R

R

R

PRES.

P

P

P

SECTION

0

1

METERS

0 . 5 -

1 . 0 -

Core

Catcher

LITHOLOGY

VOID

_-i_-_rt_-_-LZ -_-

DEFORMATION |

LITHO.SAMPLE

CC


ZEOLITIC CLAY, black (Nl), greasy, severedrilling disturbance.

Interbedded CHERT, black (Nl).

SS at CCClay A Nannos RCarbonate Rads R

unspecified R Zeolites C

Nl

Site 367 Hole Core 11 Cored I n t e r v a l : 350.0-359.5 m

AGE

|

MIDDLE EOCENE

ZONES

FORAMS

NANNOS

RADS

-

FOSSIL

CHARACTER

FOSSIL

N

F

R

ABUND.

R

R

PRES.

P

P

SECTION

0

1

cCa

METERS

0.5—

1.0 —

re

.cher

LITHOLOGY

VOID

EtSfe=

T.—~ 2

DEFORMATION

LITHO.SAMPLE

CC


ZEOLITIC CLAY AND CHERTZEOLITIC CLAY, alternations of 2 to 10 cmthickness of black (Nl) and greenish gray(5GY 6/1), very stiff, drilling disturbancehas washed out softer material. Black clayis greasy.

Interbedded CHERT, greenish black (5G 2/1)occurs scattered through. The chert is

.., bedded and grades from the greenish gray

"nd c l a

*5 G*

6/l SS at CC

Clay D Zeolites C

Carbonate Rads R

unspecified R Fish debris R

AGE

UJ

CE

UJ

ZONES

FOR/

SOK

NAN

αva

'iata

4->

ata

in <Λ

à Po °-

ata

lin

u(O

'öj>,

FOSSILCHARACTER

FOS

M

p

N

o

ABU

p

C

p

M

mo:

0

10.5-

-

-

CoreCatcher

LITHOLOGY

*i-Jt--Z--Jt

-_-*-_-.*_-_».-:JtπZ^-1ttZ"-~N"

_-_*_-_A-:

""-"t-"

c"-

o

RMAT

DEFO

O.SAMPL

LITH

/8

12b

CC


ZEOLITIC NANNO CLAY, CLAY AND CHERT

CLAY, greenish gray (5GY 6/1), stiff,

slight drilling disturbance, burrowed.

Thin interbeds of ZEOLITIC NANNO CLAY,black (Nl), very stiff, slight drilling

5GY 6/1 disturbance, greasy.

distinct bed 70 to 90 cm and 120 cm.

SS at 78 (dominant lithology)

Clay A Carbonateunspecified

(crystals) R

SS at 107 (minor lithology)

Clay A Forams CZeolites C Nannos A

Carbonate Rads Rcrystals R

SS at CCHeavy minerals R Rads RCarbonate Fish debris R

crystals R Nannos R


FOSSILCHARACTER

Core

Catcher


5G 4/1and5GY 5/2

ZEOLITIC CLAY WITH INTERBEDDED CHERT.

ZEOLITIC CLAY, dark greenish gray (5G 4/1),and minor dusky yellow brown (5GY 5/2),very stiff, thin interbeds (<0.5 cm) ofthe yellow brown clay in Section 1, moderatedrilling disturbance separating coherentblocks, burrowed, fine Mn laminations,sharp contacts.

CHERT, dark greenish gray (5G 4/1) in Section

2 and 0-5 cm Section 3; the rest of chert

in Section 3 is medium bluish gray (5B 5/1),

abundant burrows.

SS at 1-66 (minor lithology)Clay A NannosZeoli tes R Fe/Mn

SS at 2-115 (dominant lithology)Clay A ZeolitesCarbonate

rhombs R

SS at 2-120 (minor lithology)Clay A ZeolitesCarbonate

rhombs R

SS at CCHeavy mineralsCarbonate

rhombs


ClayRadsZeolites


Site 367 Hole Core 14 Cored Interval :378.5-388.0 m

FOSSILCHARACTER

Z. -V---: Z h_~_-

CoreCatcher

- ----_r-_-_— Z _-


5G 4/110Y 4/25G 8/1and5YR 4/1

ZEOLITIC CLAY WITH INTERBEDDED ZEOLITICCLAYEY SAND, CHERT AND PORCELLANITE.

ZEOLITIC CLAY, dark grayish green (5G 4/1),grayish olive (10Y 4/2), light greenishgray (5G 8/1), and brownish gray (5YR 4/1)all interbedded at 5 to 10 cm thicknessesand with gradational color contacts, verystiff to subfissile, burrowed, finelylaminated, pyrite present in layers.

ZEOLITIC. CLAYEY SAND, dark grayish green(5G 4/1), fine to medium-grained,occurs as thin (2 to 10 cm) lenses.

CHERT AND PORCELLANITE. , dark greenishgray (5G 4/1), to grayish olive green(5GY 3/2), burrowed, sharp basal contactand gradational upper contact with clay.

SS at 1-125 (dominant lithology)Heavy minerals R Zeolites RClay D Rads R

SS at 2-83 (dominant lithology)Clay A Zeolites A

SS at 2-96 (minor lithology)Quartz A ZeolitesClay C Fish debrisGlauconite R

SS at 4-40 (minor lithology)Quartz C ZeolitesClay D

SS at CC (minor lithology)

SS at CCQuartzHeavy mineralsClayZeolites

Carbonaterhombs

Fe/MnNannosFish debris

Carbonate Bomb: 3-122 to 123

CARBON-CARBONATE2-39 (O•l-O•>O)

Site

|

AGE

ENE

j

367

ZONES

I FO

RAMS

| NANNOS

1 RA

DS

Hole

FOSSILCHARACTER

| FO

SSIL

N

NFR

| AB

UND.

R

| PR

ES.

_

µ

Core 15

1 SE

CTIC

U

1

2

i

4

5

METER!

-

0 . 5 --_-

_-

-

-

-

-

1 1

_-

-

-

Mil

-_-'

-

_

i

Core .Catcher

Cored I

LITHOLOGY

VOID

-„-.. .÷~.

--_—^_-_T-_"_-

— . - — - . - T.-.-T

. i^J~J^»-•n-T-.,-„-

- — T

ΔΔΔΔΔ

"– -M-•— _• !_ i j _

1_-

- - - - - - -

T T —--7-T-.-

πter

o

1 DEF

ORMA

T

val

UJ

Q_

1 LI

TH0.

SA1

RΠ

20

CC

473.5-483.0 m

• LITHOLOGIC DESCRIPTION

SILTY CLAY AND SAND

..SILTY CLAY, alternating interbeds ofgrayish blue green (5BG 5/2) and darkreddish brown (10R 3/4), f i rm to sub-f i s s i l e , broken by d r i l l i n g , sharpcontacts between the two colors, burrowedand f a i n t laminations. Thin (0.5 cm)CLAYEY SAND beds scattered throughout.

π 5BG 5/2 Section 4.

10R 3/4 PORCELLANITE, greenish gray (5G 6/1)

occurs at 4-40. I t is.mottled and has Mn5BG 5/2 streaks and pyr i te crystals wi th in i t .

SS at 1-135 (minor Titholoqy)IUR 3/4 Quartz A Heavy minerals R

SS at 3-80 (dominant l i thology)5BG 5/2 Quartz C Heavy minerals R

_, Clay D

-t 1 0 R 3 / 4 SS at 4-20 (dominant l i tholoqy)1 Quartz C Mica R

Heavy minerals R Clay D5BG 5/2 Zeolites R Fe/Mn R

Fish debris R

, 1 0 R 3 / 4 SS at CCQuartz C Fe/Mn RFeldspar R Fish debris RHeavy minerals R Clay A

5BG 5/2Carbonate Bomb: 3-63 to 64 cm = 0.5%

I| 1 OR.3/4 CARBON-CARBONATEJBG j / t ;>_fa;> (o. 1-0.1-0)

1 10R 3/4 4-52 o.l-O.l-O^\ 5BG 5/2 '

GRAIN SIZE2-64 (0.4-16.3-83.3) Clay4-53 (0.3-41.4-58.3) S i l t y clay

10R 3/4

H 5BG 5/2

H 10R 3/45BG 5/2


Site 367 Hole Core 16 Cored Interval: 540.0-549.5 m Site 367 Hole Core 17 Cored Interval : 616.0-625.5 m

0.5- -_-_-_-_--"-"

o


10R 3/4TOR 3/4

5BG 5/2

10R 3/4

5BG 5/210R 3/4

5BG 5/2TOR 3/45BG 5/210R 3/45BG 5/2

10R 3/4

5BG 5/2

10R 3/45BG 5/210R 3/4

10R 3/4

10R 3/4

5BG 5/2

CLAY, alternating interbeds of grayishblue green (5BG 5/2) and dark reddish brown(10R 3/4), f irm to subf issi le, broken byd r i l l i n g , sharp to gradational color con-tacts, burrowed, faint lamintions.

Mn band at 102 cm and Mn-fil led burrows(especially chondrites).

SS at 2-40 (dominant l ithology)Quartz A Fe/Mn RFeldspar R Rads RHeavy minerals R Clay A

SS at 2-120 (dominant l ithology)QuartzClay

SS at CCQuartzHeavy minerals

Heavy minerals R

ClayCarbonate

unspecified

CC has nodule of carbonate with pyritecrystals.

Carbonate Bomb: 3-110 to 111 cm • OX


GRAIN SIZE2-53 (0.6-18.6-80.8) Clay5-42 (0.2-12.1-87.7) Clay

FOSSILCHARACTER

CoreCatcher


CLAY, dark grayish blue green (5BG 5/2),subfissile, laminated, burrowed. Sharpcontact with:

SHALE, black (Nl), burrowed slightly,gas-bearing (burns when ignited),

Section 3 at 30 to 38 cm has solidmaterial with white crystals (M cm long),possibly barite which has been replacedby pyrite with depth. Also occur at 4-68 cm.

SS at 1-121 (minor lithology)Quartz R Fe/Mn RClay D Fish debris R

SS at 1-127 (dominant lithology)Quartz R Fish debris RHeavy minerals C Clay D

Carbonate Bomb: 3-73 to 74 cm = OX


GRAIN SIZE2-128 (2.6-15.2-82.2) Clay

5BG 5/2


tooto

Site

AGE

-Y

TU

RO

NI/

EAR

367

ZONES

FOR

AM

S

NA

NN

OS

RA

DS

Hole

FOSSILCHARACTER

FO

SS

IL

N

N

N

R

N

FN

AB

UN

D.

C

R

_

RR

PR

ES

.

P-M

P

_

p

Core 18

SE

CT

IC

0

1

2

3

4

5

ME

TER

ST

l 1 1

1

1 . 0 -

-

:

;

:

-

II

I!

-

CoreCatcher

Cored I n t e r v a l :

LITHOLOGY

VOID

nIIPnmSiciI

m

DE

FO

RM

AT

1PLE

LIT

HO

.SA

I

80

138

112

636.0-644.5 m.


SHALE, black ( N l ) , f i s s i l e , hard, gas-bear ing , f a i n t burrowing but r a r e , p lantdebr is and f i s h ske le ta l mater ia l commonlyfound on f i s s i l e bedding planes. Smalll i g h t colored specks scattered but ra re .

Section 3-92 to 94 cm has p y r i t elaminat ions (M mm t h i c k ) .

Thin s i l t s scattered throughout Section 5.

Clay A Zeol i tes CFe/Mn C

SS at 2-138 (minor l i t h o l o g y , white speck)Clay A CarbonateZeo l i tes C c rys ta l s A

SS at 4-112 (dominant l i t h o l o g y )Quartz R Fe/Mn CClay D Forams RZeo l i tes R Nannos R

SS at 5-98 (dominant l i t h o l o g y )Nl Quartz R Zeol i tes R

Heavy minerals R Fe/Mn RClay D Nannos R

Carbonate Bomb: 3-94 t o 95 cm = 0*


Site 367 Hole Core 19 Cored Interval: 644.5-654.0 m



SHALE, black (Nl), fissile, hard, gas-bearing, disseminated pyrite and thin(•vl mm) pyrite laminae throughout.Whitish flecks scattered. Burrows (?)occur. A few dark grayish green (5G 4/2)laminae begin to appear in Section 2.

In Sections 3 and 4 thin ( 2 mm) light-colored carbonate TURBIDITES occurwith organic debris concentrated at thebase. These occur at: 3-59, 3-77, 3-83,4-40 and 4-110.

SS at 2-65 (dominant lithology)Quartz R Zeolites CHeavy minerals R Fish debris R

SS at 3-58 (minor lithology)Quartz C Nannos RClay A Rads RForams A Fish debris R

SS at 4-53Heavy mineralsClay

SS at CCQuartzClay

Zeoli tesNannos

Fe/MnCarbonatecrystals

Carbonatecrystals


Site 367 Hole Core 20 Cored I n t e r v a l : 684.5-692.5 m Site 367 Hole Core 21 Cored I n t e r v a l : 692.0-701.5 m


SHALE, black (N l ) , f i s s i l e , hard, gas-bearing, burrowed, d r i l l i n g disturbancevaries from s l i gh t to severe.

Thin tu rb id i tes (• 5 mm) of l i g h t grayishblue green (5BG 5/2) occur in Section 4.

SS at 1-122 (dominant l i t ho logy )Quartz R Fe/Mn RHeavy minerals R

SS at 2-61 (minor l i t ho logy )Clay A Forams RFe/Mn R Nannos A

SS at 4-22 (minor lithology)Quartz R Fe/Mn RClay A Nannos CZeolites R

toO


NANNO BEARING SILTY SHALE, black (Nl),fissile, hard, gas-bearing, burrowed inplaces, faintly laminated in places, color

Disseminated pyrite occurs.

Section 2 has pyrite-fi11ed burrows andthin (3 to 26 cm) silty TURBIDITES at58^61 and 124 to 150 cm, olive gray (5Y 4/1).

Section 3 TURBIDITES occur 16 to 27 and 98cm.

Section 4 TURBIDITES 32 to 50 cm.

Section 5 TURBIDITES 34 to 35, 102, 146 to148 cm.

Section 6 TURBIDITES common.

Whole core badly disturbed by drilling.

Core catcher has 20 cm length of LIMESTONE,pale green (10G 6/2), burrowed.

SS at 2-60 (minor lithology)Quartz R Clay ANannos C

SS at 2-59 (minor lithology)Clay A Forams RNannos C

SS at 2-68 (dominant ]ithology)Quartz C Heavy minerals RClay A Zeolites RForams R Nannos C

SS at 6-40 (minor lithology)Quartz R ClayCarbonate Forams

rhombs R NannosOstracod R

NannosSS at CC

Forams

Carbonate Bomb: 3-45 to 46 cm



Site 367 Hole Core 22 Cored Interval: 720.5-730.0 m Site 367 Hole Core 23 Cored Interval:777.5-787.0 m


ALTERNATIONS OF SHALE CLAY AND SILTTURBIDITES.

NANNO-BEARING CLAY, dark gray black (N3)to dark greenish black (5G 2/1) to darkgreenish gray (5G 4/1), hard, burrowed,faint laminations, severe drilling dis-turbance (broken).

SHALE, black (Nl), fissile, gas-bearing,burrowed, severe drilling disturbance.

Clays are interbedded with thin quartzsilt turbidites (1 on to 12 cm thick)scattered throughout the core.

SS at 2-37 (dominant lithology)Quartz R ClayForams R NannosRads R Fe/Mn nodules

SS at 2-97 (dominant lithology)Heavy minerals R ClayCarbonate Foramscrystals R Nannos

Rads R PyriteFe/Mn nodules C

SS at 2-138 (minor lithology)Quartz D NannosFeldspar R Fish debrisHeavy minerals R

SS at 3-51 (minor lithology)Dolomite D Nannos

SS at 5-78 (minor lithology)Quartz R NannosClay A Pyrite


FOSSILCHARACTER

CoreCatcher


INTERBEDDED SHALE AND CLAY.

SHALE, black (Nl), fissile, broken bydrilling.

CLAY, black (Nl), destroyed by drilling.

SIDERITE-STONE, occurs at 2-16 to 26 and2-85 to 92 cm.

SS at 1-10 (minor lithology)Quartz C Clay 0Heavy minerals C Nannos R

SS at 2-75 (minor lithology)Quartz A Glauconite RHeavy minerals R Fish debris RClay A

SS at 2-90 (minor lithology)Carbonate Clay Ccrystals Fe/Mn R(siderite) A

Carbonate Bomb: 2-70 to 71 cm = 0*


S i t e 367 Hole Core 24 Cored I n t e r v a l : 834.5-844.0 m

FOSSILCHARACTER

CoreCatcher



CLAYSTONE, dark reddish brown (10R 3/4)interbedded with dark greenish gray(5G 4/1) to dark gray (N3) , burrowedwith green color within red color only,homogeneous.

SS at 2-30 (dominant l i tho logy , red)Quartz R Clay DZeolites R

SS at 2-122 (dominant l i tho logy, green)Quartz R Heavy minerals RClay D Fish debris R

10R 3/4

5G 4/1

10R 3/4

RClayNannos

Carbonate Bomb: 2-125 to 125 = 0%3-47 to 48 = 0%


Site 367 Hole Core 25 Cored Interval : 891.5-901.0 m Site 367 Hole Cored Interval : 910.5-920.0 m


5Y 4/1N7

N5and5Y 4/1

N7

5Y 4/1

N7

5Y 4/1

N7

5Y 4/1

NANNO-BEARING LIMESTONE, light gray (N7)to medium gray (N5), and olive gray(5Y 4/1), hard, light gray facies isbioturbated, darker facies are not, bothare laminated, and contain some gas.

Hicrofractures and inclined laminae occur,and some scour features at contacts.

Contacts are sharp going upwards from lightgray to olive gray but gradual going fromolive gray to light gray.

Pyrite nodules occur at 2-130 and 3-78 cm.

SS at 3-70 (dominant lithology)Nannos C

SS at 1-123 (dominant lithology)Quartz R Clay CCarbonate Nannos A

crystals A

SS at 3-39 (minor lithology)Clay A Fe/Mn RNannos A

R Carbonatecrystals

Carbonate Bomb: 3-91 to 92 cm = 94%


5Y 2/1N7

5Y 2/1

5Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1N75Y 2/1


N75Y 2/1

ALTERNATIONS OF LIGHT GRAY LIMESTONEAND OLIVE BLACK MARLSTONE.

NANNO-BEARING LIMESTONE, light gray (N7),burrowed, Mn streaks and burrow fillings.

NANNO MARLSTONE, olive black (5Y 2/1),laminated, aptychi visible, gas-bearing,pyrite lenses.

Color contacts show actual position ofthe facies.

Contacts between the two facies aresharp to gradational.

Thin COAL lense at 4-31 cm.

SS at 1-60 (dominant lithology)Carbonate Nannos C

crystals A

SS at 2-40 (minor lithology)Quartz R Clay ANannos A

3-20 (11.0-0.1-91)3-31 (10.6-0.1-88)3-41 (9.4-1.1-69)32 ( )

Clay ANannos ACARBON-CARBONATE2-89 (10.4-1.9-71)3-11 (10.7-0.1-88)3-20 (11.0-0.1-91)3-31 ( 1 )3- ( )3-52 (10.3-0.1-85)3-61 (10.8-0.1-90)3-71 (7.6-0.8-56)3-77 (11.3-0.0-94)3-91 (10.7-0.1-89)3-102 (10.3-0.1-85)3-111 (7.5-0.7-56)3-121 (9.2-0.8-70)3-131 (9.8-0.1-81)3-141 (10.5-0.1-87)3-150 (10.4-0.1-86)

Fe/Mn

o

<wöw>


too

Site 367 Hole Core 27 Cored Interval : 939.0-948.5 m Site 367 Hole Core 29 Cored Interval : 996.0-1005.5 m


5Y 4/1N7

N 7 " • •5Y 4/1

N7

5Y 4/1

N7

5Y 4/1N75Y 4/1

N7

5Y 4/1

ALTERNATIONS OF LIGHT GRAY LIMESTONEAND OLIVE BLACK TO OLIVE GRAY SHALEAND MARLSTONE.

SHALE, olive black (5Y 2/1), fissile,gas-bearing, disseminated pyrite, afew aptychi found.

NANNO LIMESTONE, light gray (N7), burrowed,wavy laminations, some parallel (•l mm),Mn streaks common.

NANNO MARLSTONE, varicolored olive gray(5Y 4/1), finely laminated, gas-bearing,aptych.i -bearing.

All contacts are fairly sharp althoughsome show diffusion(T) of colors into thesurrounding limestone.

SS at 1-131 (minor lithology)Quartz R Glauconite RHeavy minerals R Nannos AClay A Fe/Mn R

SS at 3-94 (minor lithology)Clay A Fe/MnPyrite C Nannos

SS at 3-60 (dominant l i thology)Calcite Forams

crystals A Nannos

Carbonate Bomb: 3-84 to 85 cm = 92%CARBON-CARBONATE1-130 (5.0-1.7-27)3-140 (10.5-0.1-87)



ALTERNATIONS OF LIGHT GRAY LIMESTONEAND OLIVE BLACK TO OLIVE GRAY SHALEAND MARLSTONE.

NANNO MARLSTONE, varicolored olive gray(5Y 4/1), finely laminated, aptychi-bearing.

NANNO-BEARING LIMESTONE, light gray (N7),burrowed, some faintly wavy laminations,Mn streaks throughout, small chert noduleat Section 2-48 cm.

SHALE, olive black (5Y 2/1), fissile,aptychi-bearing.

SS at 2-2 (minor lithology)Pyrite R Clay AFe/Mn R Calcite rhombs RNannos A Fish debris R


unspecified D



5Y 4/1

NANNO-BEARING LIMESTONE, light gray (N7),burrowed, Mn streaks common, has faintwavy laminations in places, occasionalCHERT nodules, medium gray (N5).

Thin bed of NANNO MARLSTONE, varicoloredolive gray (5Y 4/1), finely laminated.Occurs at 2-38 to 43 cm.

SS at 1-55 (minor lithology)Quartz C Nannos CCalcite A

SS at 1-70 (dominant lithology)Quartz R Calcite ANannos C

Carbonate Bomb: 2-40 to 41 cm = 97%2-106 to 107 cm = 96X


Site 367 Hole Core 30 Cored Interval: 1024.5-1034.0


ALTERNATIONS OF LIGHT GRAY LIMESTONEAND PALE TO DARK BROWN AGILLACEOUSLIMESTONE AND MARLSTONE.

NANNO-BEARING ARGILLACEOUS LIMESTONE,pale yellowish brown (10YR 6/2), finelylaminated, porcellanite nodule at 1-16 cm.

NANNO MARLSTONE, varicolored dark yellowishbrown (10YR 4/2), finely laminated, gas-bearing, sulfide minerals scattered through-out.

NANNO-BEARING LIMESTONE, light gray (N7),bioturbated, pyrite streaks and disseminatedwith sulfides.

SS at 1-10 (minor lithology)Quartz R AlbiteCarbonate Clay

unspecified A Nannos

SS at 1-30 (dominant lithology)Carbonate Nannosunspecified D

SS at 1-36 (minor lithology)Heavy minerals R ClayPyrite R Fe/MnForams R Nannos

SS at 1-101 (minor lithology)Clay A Fe/MnPyrite R Nannos

SS at 2-133 (minor lithology)Quartz R CarbonateNannos C unspecified

CARBON-CARBONATE SS at CC1-81 (10.5-0.1-87) Carbonate Albite1-111 (9.8-0.5-77) unspecified D Nannos1-131 (11.2-0.1-93)2-140 (11.1-0.1-92) Carbonate Bomb: 2-141 to 142 cm - 92*


Core 31 Cored Interval : 1053.0-1062.5 m Site 367 Hole Core 32 Cored Interval : 1081.5-1091.0


N7 to 5GY 6/1snf ‰ 6/iN6 and 5GY 4/1

5GY 4/1

M7 to 5GY 6/1

N6 and 5GY 4/15GY 4/1N7 to 5GY 6/15GY 4/1

TS 30-33N7 to 5GY 6/1

5GY 4/1N7 to 5GY 6/15GY 4/1N7 to 5GY 6/1

TS 119-122


ALTERNATIONS OF LIGHT GRAY LIMESTONEAND DARK GRAY MARLSTONE.NANNO-BEARING LIMESTONE, light gray (N7)to greenish gray (5GY 6/1), bioturbatedor laminated but not both, pyrite-bearingand Mn(?) streaks, stylolites occur at119 to 127 era. PORCELLANITE zones,medium light gray (N6) and dark greenishgray (5GY 4/1).

NANNO MARLSTONE, dark greenish gray (5GY 4/1)varicolored, finely laminated, sulfideminerals scattered, aptychi-bearing.

SS at 1-28 (dominant lithology)Clay A Fe/MnPyrite R Nannos

SS at 1-70 (dominant lithology)Carbonate

unspecifiedNannos

Fe/MnNannos

o


N7and5GY 6/1

5YR 6/1to2.5YR 2.5/4

NANNO-BEARING LIMESTONE, light gray (N7)to greenish gray (5GY 6/1), bioturbated,faintly laminated, sulfide mineralsscattered throughout. Thin (2 to 5 cm)zones of NANNO MARLSTONE, dark greenishgray (5GY 4/1), shaley in Section 3 at90 and 125 cm. Stylolites rare.

Thin stringers or nodules of PORCELLANITE,medium light gray (N6) occur.

At Section 5-60 cm abrupt color change.(Contact possibly destroyed by drilling.)

NANNO-BEARING ARGILLACEOUS LIMESTONE,light brownish gray (5YR 6/1) to darkreddish brown (2.5YR 2.5/4), wavylaminations, stylolites, a 5 cm thickturbidite occurs at 5-85 to 90 cm.

SS at 2-43 (minor lithology)Clay A Pyrite RNannos A


unspecified D

SS at 3-24 (minor lithology)Quartz R CarbonateRutile R unspecified AClay A Nannos C

SS at 5-97 (minor lithology)Quartz R Chlorite RCarbonate Rutile R

unspecified A Nannos C



to

gSite 367 Hole Core 33 Cored Interval : 1105.5-1111.0 m Site 367 Hole Core 34 Cored Interval: 1111.0-1119.5


5YR 6/1to2.5YR 2.5/4

5G 5/2

NANNO-BEARING ARGILLACEOUS LIMESTONElight brownish gray (5YR 6/1) to darkreddish brown (2.5YR 2.5/4), wavylaminations, burrows, light gray (N8)clay nodules with laminae that goaround, stylolites are common, inclinedbedding at 1-67 to 70 and 1-92 to 96.Slump at 1-24 to 26 with a calcareniteabove it. Cycles, possibly turbidites,occur.

NANNO-BEARING MARLSTONESection 2 has thingreenish gray (5GY 6/1)layers. Section 3 at45 cm begins grayishgreen and very lightgray (N8) unit.Saccocoma occur inbands.

PORCELLANITE, light bluish gray (5B 7/1)occur, always just above a dark grayishgreen (10G 4/2) 11th.

SS at 2-70 (dominant lithology)Quartz R CarbonateClay C unspecifiedNannos C

SS at 2-130 (dominant lithology)QuartzAlbite?Rutile

SS at 3-76QuartzAlbiteHeavy mineralsClay

Carbonateunspecified

Nannos

PyriteCarbonate

unspecifiedNannos

SS at 3-88 (dominant l i thology)Clay C Calcite

CARBON-CARBONATE3-119 (.10.4-0.0-87)

10Y 6/2to10R 3/4


10R 3/4

INTERBEDDED NANNO-BEARING ARGILLACEOUSLIMESTONE AND LIMESTONE. Interbeddingindicated by color breaks.

NANNO-BEARING ARGILLACEOUS LIMESTONE,pale red (10R 6/2) to dusky red (10R 3/4),very hard, stylolites, breccia beds, wavylaminations, pods of caicitef?) displayingboudinage structure, inclined beds, scourmarks?, interbedded claystones, somecoarse silt and clay interbeds with sharpupper and lower contacts.PORCELLANITES/CHERTS always occur justabove a dark red marl stone, some looklike breccia replacement, some like voidfillings.

LIMESTONE, very light gray (N8), stylolites,mottled, possible brecciation, Saccocomarare.

SS at 1-64 (minor lithology)Quartz R Albite? RHeavy minerals R Clay APyrite R CarbonateNannos C unspecified A

SS at 1-121 (minor lithology)Quartz R CarbonateAlbite R unspecified D

SS at 2-36 (dominant lithology)Quartz R Albite?Carbonate

unspecified D

SS at 2-102 (dominant l i thology)Quartz R ClayAlbite R CarbonateHeavy minerals R unspecifiedNannos C

SS at 3-78 (dominant l i thology)Quartz R ClayCarbonate Nannos

unspecified P


Explanatory notes i n Chapter

Site 367 Hole Core 35 Cored Interval:1119.5-1127.5 Site 367 Hole Core 36 Cored Interval: 1127.5-1135.0 m


10R 6/2to 10R 3/4

10Rto

6/210R 3/4

TOR 4/2N8I ORtoN85GN8

6/210R 3/4

4/1

10R 4/210Rto10R10Rto:>•5G10R10Rto10R5G

6/210R 3/44/26/210R 3/4

4/14/26/21OR 3/44/24/1

ALTERNATIONS OF RED, GREENISH GRAY ANDLIGHT GRAY LIMESTONE.

NANNO-BEARING ARGILLACEOUS LIMESTONE,pale red (10R 6/2) to dusky red (10R 3/4),stylolites, breccia beds, wavy laminations,pods of calcite, boudinage structures,interbedded coarse silts and clays, witheither gradational and sharp contacts.Rare Saccocoma, sulfide minerals incalcite veins, shell fragments, halosof green stain. Thin CALCARENITES.

LIMESTONE, very light gray (N8), to verylight grayish green (5G 9/1), stylolites,mottled, rare Saccocoma.

LIMESTONE, dark greenish gray (5G 4/1),homogeneous to finely laminated.

LIMESTONE, grayish red (10R 4/2), finelylaminated, with some dark greenish gray(5G 4/1) along laminae, burrowed.

PORCELLANITES AND CHERTS, pale red (10R6/2), dusky red (10R 3/4), very light gray(N8), and grayish red (10R 4/2).

SS at 2-74 (minor lithology)Quartz R Albite RHeavy minerals R Clay APyrite R CarbonateForams? C unspecified ANannos C

SS at 3-100 (minor l i tho logy)Quartz R Forams ANannos C

SS at 4-34 (dominant lithology)Quartz R CarbonateAlbite R unspecified DHeavy minerals R Nannos R

SS at 4-103 (dominant lithology)Quartz R Albite RClay A CarbonateNannos C unspecified A

SS at 5-140 (dominant lithology)Albite R ForamsCarbonate Nannos

unspecified D



10R 6/2 to10R 3/4

ALTERNATIONS OF PALE RED ARGILLACEOUSLIMESTONE AND LIGHT GRAY LIMESTONE.

NANNO ARGILLACEOUS LIMESTONE, pale red(10R 6/2), to dusky red (10R 3/4), wavylaminations, breccia beds, pods ofcalcite, boudinage structure, interbeddedcalcisiltites, gradational contacts.

LIMESTONE, very light gray (N8) to verylight grayish green (5G 9/1), mottled,pods of calcite, boudinage structures.

SS at 2-32 (minor lithology)Quartz R Albite RHeavy minerals R Clay APyrite R Nannos A

SS at 2-40 (dominant lithology)uartzHeavy mineralsCarbonate

unspecified

CARBON-CARBONATE

AlbiteChalcedonyNannos

10R 6/2 to10R 3/4

N8 to5G 9/1

2-15?-45

3.2-0.1-68)3.5-0.1-70)

Site 367 Hole Core 37 Cored Interval :1135.0-1142.0 m

tooO


TOR 6/210R 3/4,

5G 9/1

NANNO ARGILLACEOUS LIMESTONE, pale red(TOR 6 /2 ) , dusky red (1OR 3/4) and l i g h tgreenish gray (5G 9 / 1 ) , wavy laminat ions,scours, coa rse -s i l t in terbeds, burrowed,lighter-colored lithology has fair lyabundant calcite replaced rads.

SS at 1-70 (minor lithology)Quartz R Clay APyrite R CarbonateNannos A unspecified C

SS at 1-80 (minor lithology)QuartzNannos CRads t


Carbonateunspecified


to

oSite 367 Hole Core 38 Cored I n t e r v a l : 1142.0-1148.0 m Site 367 Hole Core 40 Cored Interval :1151.0-1153.0 m

CoreCatcher


5YR 6/1and5G 6/1

NANNO-BEARING ARGILLACEOUS LIMESTONE,l i g h t brownish gray (5YR 6/1) and greenishgray (5G 6/1), microcrysta l l ine, burrowed.

BASALT, black ( N l ) , c a l c i t e veined,c h l o r i t e and pyr i te often l i n e inside ofamvqdules but also α l a s s - f i l l e d vesicles.Basalt is aphanitic and vesicular. At3-54 cm zeol i te(?) f i l l e d vesicles abruptlyappear. By 3-70 the basalt begins to showlaths although i t is s t i l l almost i n d i s t i n c t .By 3-107, numerous g l a s s - f i l l e d vesiclesappear. Some calc i te veins surrounded bydark red mineral (3-55 to 65) clasts ofs o f t argillaceous limestone wi th in thebasalt, even in Section 3.

SS at 1-138 (dominant l i tho logy)Clay C PyriteCarbonate Nannos

unspecified A

SS at 2-35 (dominant l i thology)Chlori te R ClayCarbonate Nannos

unspecified A

Possible flow u n i t s : 2-27 to 3-33 cm3-53 to 3-105 cm3-105 to 3-150 cm

CARBON-CARBONATE

2-35 (6.8-0.1-56)

AGE

ZONES

FORAMS

NANNOS

RADS

FOSSIL

CHARACTER

FOSSIL

ABUND.

PRES.

SECTION

0

1

Cc

Cat

METERS

0.5-

1 .0 —

re

cher

LITHOLOGY

DEFORMATION

LITHO.SAMPLE


BASALT, black (Nl), calcite veinedand chlorite, chert clast at 40 cm,disseminated pyrite throughout,amygduloidal with green mineral andpyrite and glass fillings. Grain size

Nl larger than in Core 40.


Site 367 Hole Core 39 Cored I n t e r v a l : 1148.0-1151.0

AGE

ZONES

FORAMS

NANNOS

RADS

FOSSIL

CHARACTER

FOSSIL

ABUND.

PRES.

SECTION

0

1

2

Co

Ca

METERS

II

1 1

1.0-

re

tcher

LITHOLOGY

VOID

DEFORMATION

LITHO.SAMPLE


BASALT, breccia clasts of unaltered,thick chlorite zones, calcite veins,amygdules filled with clear crystalsand/or white, soft material, common,pyrite disseminated throughout, chertclast at 118 cm.

Nl


Ocm

•25

-50

75

100

125

150

367-1-1 367-1-2 367-1-3 367-1-4 367-1-5 367-1-6

211


—Ocm

25

—50

75

— 100

— 125

—150367-2-1 367-2-2 367-2-3 367-2-4 367-2-5 367-2-6

212


I—Ocm

—25

—50

— 75

— 100

— 125

150367-3-1 367-3-2 367-4-1 367-4-2 367-4-3 367-4-4

213


I—Ocm

—50

•25

— 75

— 100

— 125

150367-4-5 367-5-1 367-6-1 367-7-1 367-8-1 367-8-2

214


r—Ocm

—25

—50

— 100

125

1—150367-8-3 367-8-4 367-8-5 367-9-1 367-10-1 367-11-1

215


—50

I—0cm

—25

—-75

100

— 125

1—150367-12-1 367-13-1 367-13-2 367-13-3 367-14-1 367-14-2

216


I—Ocm

—25

—50

— 75

— 100

— 125

1—150367-14-3 367-14-4 367-15-1 367-15-2 367-15-3 367-15-4

217


I—Ocm

—25

—50

— 75

— 100

— 125

1—150367-15-5 367-16-1 367-12-2 367-16-3 367-16-4 367-16-5

218


I—Ocm

—25

— 75

— 100

— 125

150367-16-6 367-17-1 367-17-2 367-17-3 367-17-4 367-18-1

219


—Ocm

—25

—50

— 75

-100

~

125

— 150367-18-2 367-18-3 367-18-4 367-18-5 367-19-1 367-19-2

220


r—Ocm

—25

•50

—75

100

— 125

150367-19-3 367-19-4 367-20-1 367-20-2 367-20-3 367-20-4

221


—25

—50

0cm -

— 100

125

1—150367-21-1 367-21-2 367-21-3 367-21-4 367-21-5 367-21-6


I—Ocm

—25

—50

— 75

100

— 125

L-150367-22-1 367-22-2 367-22-3 367-22-4 367-22-5 367-22-6

223


—O c m π 1—i 3 1—i 1—i 1—rp" ^M^"

f •

ii n

11 i 11 i 11 I Lü LLJ

CO CQ CQ CO GO

<; <; <; ex. <I—( I—I H 1—I •—<

> > > >- ><c <c • c •=t •*.~T" ~T" ^T" T~ zπ.CL. CX. Q _ Q _ Q -

C£S C3 C£5 CD CS

o o o o oo o o o ozc πr re rπ 3^o_ Q_ α. o_ Q-

o o o o o

367-23-1 367-23-2 367-24-1 367-24-2 367-24-3 367-25-1

224


I—Ocm

h-25

1—50

75

h-100

1—125

1—150367-25-2 367-25-3 367-25-4 367-26-1 367-26-2 367-26-3

225


i—Ocm

—-25

—50

75

100

— 125

«—150367-26-4 367-27-1 367-27-2 367-27-3 367-28-1 367-28-2

226


I—Qcm

—25

-50

75

100

125

L-150367-28-3 267-29-1 267-29-2 367-30-1 367-30-2 367-31-1

227


Ocm

-25

—50

— 75

— 100

— 125

1—150367-31-2 367-32-1 367-32-2 367-32-3 367-32-4 367-32-5

228


O /*!¥» _ J B ™ I L L _ I _ _ l••• ^ ^ ^ ^ ^ ^ ^ ^ ^

J d l B•S K •J :ti ^^B I

* 1 1 I -– w •

^H ^•fl ^Mi fl • i * »j I J ' IB^BVB^B•BBWI•

— ― IfelMinl r • I I~T" B•• , I I W^‰~ >l π Ik '"" I

βl:: E l •l^p;: 11 B "" SI BE , B. ^ H J

_ 1 <^π _ — — ^ j ‰ . ^ ^ ^ ^ ^ ^ J ^ ^ ^ _ = 3 ^ f l _ _ lEü^Z—ji—>- BB B * - B ‰ B ^ ^ B H ^ _

367-32-6 367-33-1 367-33-2 367-33-3 367-34-1 367-34-2

229


— Ocm

•25

—50

75

— 100

— 125

150367-34-3 367-34-4 367-35-1 367-35-2 367-35-3 367-35-4

230


r—Ocm

•25

—50

75

— 100

— 125

I—150367-35-5 367-36-1 367-36-2 367-36-3 367-37-1 367-38-1

231


j • r • ^ • I I SB ;

, y *\ ';i I _JF^

r • L [S l i HE. I

367-38-2 367-38-3 367-39-1 367-39-2 367-40-1

232

3. site 367: cape verde basin

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