47. CRETACEOUS FORMATIONS FROM THE LOWER …...the samples studied by organic geochemistry. The Cenomanian and Turonian age of the organic-matter-rich black clay-stones indicates a

47. CRETACEOUS FORMATIONS FROM THE LOWER CONTINENTAL RISE OFF CAPEHATTERAS: ORGANIC GEOCHEMISTRY, DINOFLAGELLATE CYSTS, AND THE

CENOMANIAN/TURONIAN BOUNDARY EVENT AT SITES 603 (LEG 93) AND 105 (LEG II)1

J. P. Herbin, Institut Français du PétroleE. Masure, Département de Géologie Sédimentaire, Université Pierre et Marie Curie

andJ. Roucaché, Institut Français du Pétrole2

ABSTRACT

Geochemical characterizations of the Cretaceous formations at Site 603 are quite comparable with those at Site 105.In the Blake-Bahama and the Hatteras formations, the petroleum potential is medium (<5 kg HC/t of rock) to verylow (<0.5 kg HC/t of rock), and the organic matter is mainly of type III origin, that is, terrestrial. At the top of theHatteras Formation, there is a condensed series, which chiefly contains organic matter of type II origin, with up to 20wt.% total organic carbon content in Core 603B-34 and 25 wt.% in Core 105-9. This accumulation corresponds to theCenomanian/Turonian boundary event. An examination of dinoflagellates in the kerogen concentration assigns dates tothe samples studied by organic geochemistry. The Cenomanian and Turonian age of the organic-matter-rich black clay-stones indicates a low rate of sedimentation, about 1 m/Ma. Furthermore, the occurrence of type II organic matter in-dicates an anoxic environment with insufficient oxygen renewal to oxidize the sinking hemipelagic organic matter. Thisorganic enrichment is not related to local phenomena but to sedimentation over an extended area, because deposits arewell known in various areas with different paleodepths in the North Atlantic.

INTRODUCTION

Hole 603B was drilled in 4642 m of water on the lowercontinental rise, 270 n. mi. east of Cape Hatteras (Fig. 1).The depositional history of Hole 603B was influencedby coastal oceanic events, whereas Site 105, only 68 n.mi. to the southeast (5251 m water depth), showed mainlypelagic influences.

At Site 105, three formations were found in the Cre-taceous deposits:

1. The Blake-Bahama Formation (Hauterivian-Bar-remian), consisting of alternating dark marlstones andlimestones.

2. The Hatteras Formation (Aptian-Albian-lower Ce-nomanian), consisting of alternating green and blackshales.

3. The Plantagenet Formation (Senonian), composedof multicolored claystones.

In Hole 603B these formations occur in Lithologic UnitsIII, IV, and V. In addition, however, Hole 603B inter-sects a deep-sea fan which perhaps forms part of an apronof clastic-rich sediments of late Hauterivian-Barremianage along the lower continental margin of eastern NorthAmerica.

Previous studies of Cretaceous deposits from DSDPsites in the North Atlantic (Graciansky et al., 1982; Her-bin and Deroo, 1982; Müller et al., 1983) showed thatan event corresponding to the upper Cenomanian/Turo-

1 van Hinte, J. E., Wise, S. W., Jr., et al., [nit. Repts. DSDP, 93: Washington (U.S.Govt. Printing Office).

2 Addresses: (Herbin, Roucaché) Institut Français du Pétrole, Direction de RechercheGéologie-Géochimie, B.P. 311, 92506 Rueil Malmaison Cedex, France; (Masure) Départe-ment de Géologie Sédimentaire Laboratoire de Micropaléontologie, UA 319, Université P. etM. Curie, 4, place Jussieu, 75230 Paris Cedex 05, France.

nian boundary existed between the Hatteras Formationand the Plantagenet Formation. This event, named vari-ously the E2 Event, Cenomanian/Turonian Black ShalesHorizon, or Cenomanian/Turonian Boundary Event(CTBE), is characterized by a level of laminated blackclaystones very rich in type II organic matter (15 to40 wt.% of total organic carbon). The CTBE occurs alongthe different continental margins of the North Atlantic.Off the African continental margin it has been recog-nized at DSDP Sites 135, 137, 138, 367, and 368 as wellas on the shelf in Senegal (Casamance area) or Morocco(Agadir-Tarfaya basins and Rif Mountains) (Herbin,Montadert, et al., in press; Thurow and Kuhnt, in press).Sites 398 and 551 off the European margin also givegood opportunities to study the CTBE. However, offthe American continental margin, only Site 105 up tonow has revealed the presence of the CTBE in the west-ern North Atlantic. Condensed deposits with a high to-tal organic carbon content in Sections 105-9-3 and 105-9-4 mark the break between the Hatteras and the Plan-tagenet formations. The same phenomenon occurs overa longer interval in Sections 603B-34-1 to 603B-34-6.

This chapter has two sections. In the first, the resultsof detailed analyses of all of the Cretaceous formationsin Hole 603B (lithologic Units III, IV, and V) will bediscussed. In the second, the CTBE will be studied, firstat Site 105 and then at Site 603.

METHODOLOGY

The amount of total organic carbon (TOC) was determined by anew methodology adapted to the Rock-Eval apparatus (Espitalié etal., 1984). After pyrolysis in an inert atmosphere, where the petroleumpotential of the rock was determined (peaks S! and S2), the rock wasburned at about 600° C for 5 min. to determine the residual organiccarbon content by detecting the CO2 resulting from this combustion.

1139

J. P. HERBIN, E. MASURE, J. ROUCACHE

35C

U.S.A

Figure 1. Section along the continental margin off New Jersey and lo-cation of Sites 105, 603, and other DSDP sites.

The total organic carbon content of the sample is the sum of the resid-ual organic carbon and the pyrolyzed organic carbon. Under theseconditions, the carbonates that are decomposed by a temperature be-low 600°C (siderite, nahcolite, dawsonite, etc.) are destroyed duringthe preceding pyrolysis and cannot interfere with the combustion ofthe residue, whereas decomposition of other carbonates (calcite, dolo-mite) is very low at 600°C during such a short (5 min.) .combustiontime.

Total organic carbon and Rock-Eval pyrolysis assays were performedon 436 samples. Among the 21 samples issued by the Organic Geo-chemistry Panel (Table 1), 13 with TOC of 0.5 wt.% were selected tobe chloroform-extracted and analyzed by gas chromatography for their

saturated hydrocarbons. Elemental analysis of the kerogen was per-formed on 11 samples. Since the preparation of the kerogen concen-trates (Hue et al , 1978) was the same for the geochemical study andfor the palynological study, both were performed in the interval con-taining the CTBE (Core 34) to characterize the type of organic matterand the age for the same rock.

RESULTS

Character of the Cretaceous Formations

Mineral Carbon and Carbonates (Table 1)

In the Blake-Bahama Formation, lithologic SubunitVB (Core 603B-82 to Section 603B-76-1, late Berriasian-Valanginian in age) is very rich in carbonates (8.5 wt.%of mineral carbon, i.e., 70 wt.% of CaCO3), whereas inlithologic Subunit VA Section 603B-76-1 to Core 603B-44, Valanginian, Hauterivian, Barremian), the carbon-ate content is lower because of detrital input from thedeep-sea fan (mineral carbon = 1.9 to 3.3, CaCO3 =15.8 to 27.5), except in Sample 603B-66-2, 135-137 cm(mineral carbon = 8.28, CaCO3 = 68.9). Turbiditic silt-stones are very poor in mineral carbon (0.63; CaCO3 =5.2).

Above the Blake-Bahama Formation, in the HatterasFormation (Cores 603B-44 to -33, Aptian to Cenomanian-Turonian), the Plantagenet Formation (Cores 603B-33to -22, Senonian), and even in the Bermuda Rise Forma-tion (Cores 603B-22 to -15, Eocene), the mineral carbonis poor: 0.36 to 1.03 wt.%; 3-8.6 wt.% of equivalentCaCO3.

The change from carbonate deposits in the Blake-Ba-hama Formation to the noncarbonate deposits of theoverlying formations is a general feature of Cretaceoussedimentation in the North Atlantic realm, and corre-sponds to the El Event of Müller et al., 1983. This is in-terpreted as a rise in the carbonate compensation depth.

Organic Carbon (Table 1)

In the Blake-Bahama Formation the dark marlstonescontain 0.6 to 2.9 wt.% TOC except in the more siltyportions, where the TOC is very poor: 0.04 in Sample603B-59-4, 127-127 cm. The green and reddish claystonesof the Hatteras Formation (Samples 6O3B-38-3, 143-148cm and 603B-43-4, 10-15 cm) are low in TOC content(0.04 and 0.03) whereas the dark claystones contain 2.7to 3.4. A higher wt.% TOC is reached at the top of theHatteras Formation (Cores 603B-34 and -33) with 4.6 to20.4. This high enrichment is typical of the CTBE. High-er up in the reddish brown and green claystones of thePlantagenet Formation, the TOC content is very low (0.07to 0.14). One sample of greyish claystone of Santonianage reaches 1.78 TOC.

The same pattern holds true for the Cretaceous for-mations at Site 105. In the Blake-Bahama Formation theaverage TOC is 1.5 wt.% (26 samples), in the HatterasFormation it is about 2 (43 samples), and in the Planta-genet Formation it does not exceed 0.2. On the otherhand, at the top of the Hatteras Formation, as in Hole603 B, the CTBE is recognizable from an enrichment inorganic matter, with TOC up to 24.

1140

Table 1. Geochemical data for the samples issued from the Organic Geochemistry Panel.

Core-Section(interval in cm)

16-2, 140-143

29-1, 57-6229-3, 127-13133-2, 127-133

33-CC, 1-834-1, 82-8334-3, 70-7334-5, 23-25

35-3, 74-7638-3, 143-14843-4, 10-1544-1, 23-24

53-4, 135-13959-4, 125-13066-2, 135-13871-5, 125-130

f75-5, 17-19j 75-5, 32-34(J5-5, 47-49

76-3, 125-13081-3, 124-129

Sub-bottomdepth (m)

968.30

1081.371085.071121.27

1127.491128.321131.201133.73

1140.241167.931209.401214.63

1306.651364.151426.551475.951508.071508.221508.371515.751562.44

Formation

Bermuda Rise

Plantagenet(Unit III)

Cenomanian/TUronianBoundary Event

Hatteras ( U n i ( , y )

Deep-sea fan inBlake-Bahama (Unit VA)

Formation

(Unit VB)

Age

Eocene

Santonian

Türonian

TuranianTüronian

CenomanianCenomanian

CenomanianAlbianAptianAptian

BarremianBarremian

HauterivianHauterivianValanginianValanginianValanginianValanginianValanginian

carbon

0.70

0.360.720.75

0.661.020.840.90

0.690.900.781.03

3.300.638.282.881.902.512.638.498.40

CaCO3

(%)

5.8

3.06.06.2

5.58.57.07.5

5.77.56.58.6

27.55.2

68.924.015.820.921.970.769.9

TOC(%)

0.10

1.780.140.07

4.5820.4010.717.79

2.740.040.033.43

2.270.040.931.461.902.512.632.910.57

Si + S2(kg HC/t

rock)

0.70

0.641.110.37

15.27104.3043.3428.86

5.010.060.253.99

0.950.130.220.311.441.562.994.350.10

7"(°C)

440

420412415416

430

433

423

418424435436433425415

HI

34

324485396355

177

114

39

21137461

11114615

OI

40

31264030

91

57

81

1409092576459

164

H/C

0.67

1.111.231.191.15

0.84

0.79

0.770.660.92

0.79

o/c

0.27

0.190.180.170.15

0.20

0.20

0.220.240.19

0.20

Pyrite(%)

25

12284232

29

14

212237

32

Ash-freeof pyrite(wt.%)

2.8

1.92.52.01.9

2.1

3.6

3.82.92.7

8.0

rock

0.022

0.0790.3870.2070.125

0.030

0.038

0.032

0.0180.0160.026

0.0510.018

TOC(%)

1.2

1.71.91.91.6

1.1

1.1

1.4

1.91.11.4

1.73.1

Hydroatomiccompounds (%)

67.8

90.994.394.94.1

89.2

84.7

84.7

Hydrocarbon fraction

Aromatic(%)

5.2

5.64.22.43.3

7.1

6.1

6.4

Saturated(*)

27

3.51.53.62.6

3.7

92

8.9

PristanePhytane

1.41

1.130.781.090.84

1.11

1.39

1.39

1.431.681.90

2.081.17

Note: TOC = total organic column; Si + S2 = petroleum potential; HC = hydrocarbons; HI = hydrogen index (mg hydrocarbon compounds/g TOC); OI = oxygen index (mg oxygen compounds/g TOC); Tmax = maximum temperature.

o73a>zna§nxm2


Pyrolysis Data (Table 1, Fig. 2)

Petroleum Potential (Table 1)

The petroleum potential is defined as the sum of Rock-Eval peak S (corresponding to the free hydrocarbons inthe rock) and peak S2 (related to the hydrocarbons ex-pelled during kerogen pyrolysis) (Espitalié et al., 1977).It is expressed in kilograms of hydrocarbons per metricton of rock (kg HC/t). Five classes were considered: verygood, more than 20 kg HC/t; good, 5.01 to 20.00; me-dium, 2.01 to 5.00; low, 0.51 to 2.00; and very low, 0.50and less.

In the deep-sea fan of the Blake-Bahama Formation,the petroleum potential is very low to low except at thebottom. There, in samples of Valanginian age (Samples603B-75-5, 47-49 cm and 603B-76-3, 125-130 cm), itreaches 3 to 4.3 kg HC/t. In the greyish claystones ofthe Hatteras Formation the petroleum potential is medi-um, 4 to 5. However, it is very low in the green and red-dish claystones (0.06 to 0.25. At the top of the HatterasFormation (Core 603B-34 and -33) the petroleum poten-tial is good and even very good, with 4.6 to 104.3. Thisrichness reflects the CTBE. This high content disappearsin the multicolored claystones of the Plantagenet For-mation (0.37 to 1.11) and in the overlying Bermuda RiseFormation (0.70)

Maturation (Table 1)

During pyrolysis of organic matter by Rock-Eval, thetemperatures reached at maximum hydrocarbon produc-tion (Tmax) for peak S2 depend on both the stage of mat-uration and the nature of the organic matter (Espitaliéet al., 1985). Vitrinite reflectance can be compared withthe maturation scale derived from the Rock-Eval. A re-flectance of 0.5%, which defines the boundary betweenimmature and mature organic matter, roughly correspondst o Tmax °f 435°C for organic materials of types II andIII.

In the Blake-Bahama Formation, Tmax ranges from418 to 436°C with an average of about 426°C. The high-er values could reflect a moderate inertinite content. Thelocation of the formation above the oil window is in agree-ment with the present depth of burial (1300 to 1560 m).In the Hatteras Formation, the samples with TOC lowerthan 0.2 wt.% do not give reliable Tmax data, so onlytwo samples give reliable temperature data (430°C and433°C). In the organic-matter-rich level at the top of theHatteras Formation, Tmax is much lower because the typeof organic matter changes (average Tmax = 416°C). Thesample richer in TOC from the Plantagenet Formation(Sample 603B-29-1, 57-62 cm) gives a Tmax of 440°C,which is probably due to reworked material.

Nature of the Organic Matter (Table 1, Fig. 2)

Three types of kerogen can be distinguished from py-rolysis studies. Types I and II are related to lacustrine ormarine reducing environments and are derived mainlyfrom planktonic organisms, whereas type III comes fromorganic matter derived from terrestrial plants and trans-ported to a marine or nonmarine environment with amoderate level of degradation. Intermediate kerogens are

common, particularly between types II and III. They re-sult from a mixture of marine and terrestrially derivedorganic matter or from the biodegradation of marineorganic matter (Tissot and Pelet, 1981). A fourth typeof organic matter is residual organic matter, which maybe either recycled from older sediments by erosion ordeeply altered by subaerial weathering (Tissot et al., 1979).

In the Blake-Bahama Formation, two sets of organicmatter can be distinguished. A deeply altered, residualorganic matter occurs in the samples of Barremian orHauterivian age (Samples 603B-53-4, 135-139 cm; 603B-66-2, 135-138 cm, and 603B-71-5, 125-130 cm) and atthe bottom of the hole in Sample 603B-81-3, 124-129 cm,whereas in Cores 603B-75 and -76 the marls contain or-ganic matter of terrestrial origin (Fig. 2).

800

700

600

5 500

o

400

300

200 -

100 •

(XJ Plantagenet Fm.

Q CTBE

C/j Hatteras Fm.

^Λ Blake-Bahama Fm.

Ill

66-229-1 71-5 181-3

50 100 150 200

Oxygen index (mg CO2/g TOC)

250

Figure 2. Characterization of the organic matter in Hole 603B by py-rolysis method. Size of the circles is proportional to total organiccarbon. CTBE = Cenomanian/Turonian Boundary Event. Sam-ples identified by Core-Section number.

1142

ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603

In the Hatteras Formation, the dark claystones (withan average TOC content of 3 wt.%) contain type III or-ganic matter. This terrestrial organic matter is commonto the entire "Black Shales Formation" wherever the sitesmay be (105, Leg 11; 391, Leg 44; or 534, Leg 76, Her-bin et al., 1983). On the other hand, the high TOC con-tent at the top of the Hatteras Formation (Cores 603B-34 and -33) belongs chiefly to a type II organic matterwith a hydrogen index (HI) ranging from 324 to 485 mgHC/g TOC. The preservation of organic matter of plank-tonic origin at this level indicates an anoxic environmentwhich coincides with the Cenomanian/Turonian bound-ary.

Above the CTBE, the organic matter is residual (Sam-ple 603B-29-1, 57-62 cm) in the Plantagenet Formation.

Kerogen Study (Table 1, Fig. 3)

Eleven samples were selected from different forma-tions at Site 603 and prepared for elemental analysis ofthe kerogen concentrations (Table 1). The H/C and O/Cratios in Table 1 are plotted on a Van Krevelen diagram(Fig. 3) according to the three reference evolution pathsfor types I, II, and III kerogens from ancient sediments(Tissot et al., 1974).

An immature stage can be assigned to all samples.Samples 603B-71-5, 125-130 cm, of Hauterivian age, and603B-29-1, 57-62 cm, of Santonian age, are located be-low the limit for kerogen of types I, II or III. They con-tain degraded kerogen considered as residual organic ma-terial (Tissot et al., 1979). A group of five samples is lo-cated near the evolution path for type III; Samples603B-75-5, 17-19 cm, of Valanginian age, and 6O3B-35-3,74-76 cm, of Cenomanian age, have a higher H/C atom-ic ratio than Samples 6O3B-81-3, 124-129 cm (Valangin-ian), 603B-66-2, 135-138 cm (Hauterivian), and 603B-44-1, 23-24 cm (Aptian). From pyrolysis analysis, Sam-ples 603B-81-3, 124-129 cm and 603B-66-2, 135-138 cmwere previously interpreted as consisting of residual or-ganic matter, but the kerogen study indicates a type III

B2.0-

i-OH

0.5H

^ ― Direction of increasing evolution—— Boundaries of the domain of

existence of kerogensI I I Evolution paths of kerogens

Domain of existence of vitrinites

0.1 0.2 0.3 0.4 0.5•> O/C atomic ratio

Figure 3. Elemental analysis of the kerogen: H/C and O/C diagram.Hole 603B samples identified by Core-Section number.

origin. All samples from Cores 603B-34 and -33 are lo-cated between types II and III, with H/C ranging be-tween 1.11 and 1.23. The sample analyzed in the CTBEat Site 105 (Samples 105-9-4, 13-15 cm) with H/C =1.10 and O/C = 0.19 fits well with these samples fromSite 603. All these data indicate the presence of sometype II organic matter with a planktonic origin at thetop of the Hatteras Formation. This preservation is quitespecific to the CTBE and does not occur in either theolder or the younger sediments. The CTBE appears tobe the most favorable period for sedimentation of typeII organic matter, whereas in the other claystones onlytype III accumulated.

Chloroform Extraction Study (Table 1, Fig. 4)

The extracts collected from 13 selected samples (Ta-ble 1) represent 0.016-0.387 wt.% of rock, correspond-ing to 1.1-3.1 wt.% of extract to TOC. As is usuallyfound in DSDP sites, polar compounds with high mo-lecular weight predominate in the extract. Thus the hy-drocarbons are represented by 5.7-15.3 wt.% of the to-tal extract (exceptionally, 32.2 in Sample 603B-29-1, 57-62 cm).

Ten extracts were then selected for capillary gas chro-matography (GC) studies (Fig. 4). The GC analysis of sat-urates + unsaturates reveals comparable chromatogramsfor the samples analyzed from the Valanginian (Sample603B-75-5, 17-19 cm), Hauterivian (Sample 603B-71-5,125-130 cm), Barremian (Sample 603B-53-4, 135-139 cm),Aptian (Sample 603B-44-1, 23-24 cm), Cenomanian(Sample 603B-35-3, 74-76 cm), and Santonian (Sample603B-29-1, 57-62 cm). Predominance of odd-numberedmolecules in the «-C23 to «-C35 fraction indicates imma-ture material. Pristane slightly predominates over phy-tane in all these samples. The geological environmentcan influence the formation of the isoprenoids issuingfrom phytol after deposition or during maturation (Sev-er and Parker, 1969; Simoneit, 1973; Ikan et al., 1975a,b). The sediments where pristane is equal to or higherthan phytane should indicate an environment unfavor-able to the preservation of organic matter. The degrada-tion of phytol indicates the phytenic acid precursor ofpristene and then of pristane. In contrast, in Samples603B-34-5, 23-25 cm and 603B-34-1, 82-83 cm from theCenomanian/Turonian boundary—much richer in TOC(4.6-20.4 wt.%)—the GC study shows that phytane pre-dominates over pristane. This richness in isoprenoids,particularly in phytane, could indicate deposition in amore restricted environment. The occurrence of organicmatter of marine origin is, furthermore, suggested bythe presence of sterane/sterene, triterpane/triterpene mole-cules in the /2-C27+ range (Roucaché et al., 1979) (Fig. 4).

THE CENOMANIAN/TURONIAN BOUNDARYEVENT

Site 105

Site 105 was drilled during Leg 11 on the lower conti-nental rise hills off Cape Hatteras (Ewing and Hollister,1972). In Sections 105-9-3 and 105-9-4 (289 to 292 m), amajor lithological change marks the top of the "black

1143


Pr

Ph

i l l17.18 2 5 35 15 20 25 30 35 40

15-

10-

5-

o-15-

10-

5 •

0-25-

20-

15-

10-

5-

O •

Kl\

Pr

\

1

4

JPh

28

T718

Carbon atom number Carbon atom number

29-1, 57-62Santoniaπ

33.CC (1-8)Turoπian

34-1,82-83Turonian?

34-3, 70-73Turonian —

Cenomanian

34-5, 23-25Cenomanian

35-3, 74-76Cenomanian

44-1, 23-24Aptian

53-4, 135-139Barremian

71-5, 125-130Hauterivian

75-5, 17-19Valanginian

Plantagenet Fm.

Cenomanian/TuronianBoundary Event

Hatteras Fm.

Blake-Bahama Fm.

Figure 4. Chromatogram of the saturated + unsaturated fraction of samples from Hole 603B, Gas chromatographyanalysis on quartz col. capil. CP SIL5 (0 int: 0.5 mm, L = 25 m), injected 0.2 µl splitless (model Varian 3700). Pr =pristane, Ph = phytane.

1144


shales" sedimentation of the Hatteras Formation. Abovethis break, the Upper Cretaceous to lower Tertiary mul-ticolored claystones (from the top of Core 105-9 to Core105-5) show a very low sedimentation rate, resulting fromthe small proportion of terrigenous material and the ab-sence of calcareous and siliceous microfossils. In this in-terval, the major components of the sediments are ofvolcanic origin, with metal enrichments. This volcanicactivity can be correlated to a major phase in the tecton-ic history of the North Atlantic Ocean (Lancelot et al.,1972). Below the break (from the bottom of Core 105-9to Core 105-17, the black and olive green clays of Ceno-manian to Albian age are interpreted as reflecting the al-ternation of reducing and mildly oxidizing conditions.The TOC of the black clays in Cores 17 to 10 range be-tween 1 and 5 wt.%, and higher TOC is reached in Core9: up to 10 in Sections 105-9-5 to 105-9-6 and even up to25 in Sections 105-9-3 to 105-9-4 (Herbin and Deroo,1982). These high contents, located just within the break,underlie the stratigraphic "hiatus" between upper Ceno-manian and Senonian, at a time when the accumulationrate should have been < 1 m/Ma. New results obtainedfrom the stratigraphic synthesis of the DSDP sites in theNorth Atlantic (Müller et al., 1983) have made it possi-ble to date Section 5 at 93 cm as late Cenomanian withSections 3 and 4 being located in the CTBE.

A detailed sampling along a 7.5-m interval between287.5 and 295 m (Core 105-9 from Sections 2 to 6), al-lows study of the TOC content and the type of organicmatter in this condensed sedimentary section. A typicalalternation of black and green claystones occurs fromthe bottom of Section 6 to Section 4 at 87 cm. As in thewhole Hatteras Formation, the thickness of the green lay-ers is much greater than the black ones. In contrast, fromSection 4 at 86 cm to Section 3 at 110 cm, the lithologyis composed of about 20 sequences of black claystoneswith cm-scale to mm-scale green layers (see descriptionin Fig. 5). The TOC is very high in this interval: 10 to 25wt.% (Table 2) in contrast to the general content of theHatteras Formation (2 to 5) (Fig. 6). All the interbeddedgreen claystones have low TOC (0.35) like the moderatebrown claystones of the top of the core from Section 3at 110 cm to Section 1. In all the facies the carbonatecontents are very low (0 to 17 wt.% CaCO3).

The organic matter is mainly detrital in the lower partof Core 105-9 (Sections 5 and 6) as it was below, in theHatteras Formation. In the break from Sample 105-9-4,86 cm to 105-9-3, 110 cm, the organic matter is a mix-ture of types II and III (Fig. 6). This composition is con-firmed by the elemental analysis of the kerogen in Sam-ple 105-9-4, 13-15 cm (H/C = 1.10 and O/C = 0.19).

At 95 Ma, Site 105 was located in an abyssal paleoen-vironment; paleodepth reconstruction indicates a depthof approximately 4100 m (Chénet and Francheteau, 1979).

Site 603

Since preparation of the kerogen concentrates (Hueet al., 1978) was the same for both the geochemical study(elemental analysis) and the palynological study, bothanalyses were performed on the samples issued from theOrganic Geochemistry Panel in order to obtain informa-

tion about the age of the sediments from the marinepalynomorphs, especially dinoflagellate cysts.

Three samples from Core 34, Sample 603-33,CC, andone sample from Core 29 were analyzed. Fifty-five spe-cies were recovered (Fig. 7). Dinocysts from Core 34 arepoorly preserved, in contrast to the well-preserved speci-mens from Core 29. Comparison with well-known strati-graphic ranges established in accurately dated Europe-an, Canadian, and African onshore sections and localranges established at previous DSDP sites in the NorthAtlantic, especially Site 105, made it possible to deter-mine the age of these samples.

1. Sample 603B-34-5, 23-25 cm: Latest Albian (Vraconian) to ear-ly Cenomanian. The stratigraphically significant species are listed:

Epelidosphaeridia spinosa (Plate 1, Fig. 1) first appears in the Vra-conian of the Col de Palluel section (Davey and Verdier, 1973).Litosphaeridium siphonophorum (Plate 1, Fig. 2) first occurs inthe late Albian of France (Davey and Verdier, 1973) and of Moroc-co (Below, 1982).Odontochitina costata (Plate 1, Fig. 3) and Ovoidinium verruco-sum first occur in the Vraconian (Davey and Verdier, 1973).The assemblage is characterized by a high percentage of Cy-

clonephelium hughesii (Plate 1, Fig. 8), and Ovoidinium ovale (Plate1, Fig. 4). E. spinosa and L. siphonophorum first appear at or nearthe base of the Spinidinium echinoideum zone of Habib, 1977, in Holes105 (Habib, 1972) and 534A (Habib and Drugg, 1983).

2. Sample 603B-34-3, 70-73 cm: Cenomanian. The species are con-sidered to be stratigraphically important are listed:

Palaeohystrichophora infusorioides (Plate 1, Fig. 9) first appearsin the Vraconian (Davey and Verdier, 1973).Dinogymnium acuminatum (Plate 1, Fig. 7). The first occurrenceof Dinogymnium species is in the upper part of the Turonian fromthe Turonian stratotype area (Foucher, 1982). One specimen hasbeen recorded in the Cenomanian from the southwest of France(Azéma et al., 1981). The genus has been recorded sporadicallyfrom the middle Cenomanian of Africa (Boltenhagen, 1977). Ac-cording to Morgan (1978), S. Jardiné has found these Dinogym-nium species in African sediments older than Santonian. Speciesof Dinogymnium have not been recorded from the lower Cenoma-nian of Morocco (Below, 1981, 1982). Thus a middle or late Ceno-manian through Turonian age is suggested by dinocysts. Dinogym-nium species has been recorded in Sample 398D-56-2, 122-124 cm(Masure, 1984). Futher, the genus Dinogymnium has been observedin Sample 101A-4-1, 136-139 cm and Section 105-10-2 (Habib,1972; Habib and Knapp, 1982); these samples are dated Vraconianor early Cenomanian by foraminifers and radiolarians (Müller etal., 1983).

3. Sample 603B-34-1, 82-83 cm. Dinocysts are very rare and poor-ly preserved against a background of abundant organic matter.

Cyclonephelium vannophorum is recovered in this sample. It firstoccurs in the European Cenomanian (Davey, 1969).4. Sample 603B-33,CC, (01-08 cm): upper Cenomanian-lower Tu-

ronian. For this sample a few diagnostic species have been recorded.Trithyrodinium suspectum (Plate 1, Fig. 13) first appears in theCenomanian (Manum and Cookson, 1964).T. suspectum has been recovered in Sample 105-9-5, 88-89 cm (Ha-bib and Knapp, 1982). A late Cenomanian-lower Turonian age issuggested by radiolarians (Müller et al., 1983).Florentinia resex (Plate 1, Fig. 11) has been recorded in the Euro-pean Turonian (Davey and Verdier, 1976) and also from the Aptianand Albian of Morroco (Below, 1982).Litosphaeridium siphonophorum is present in this sample. It lastoccurs in the upper part of the Cenomanian (Foucher, 1979, 1982).5. Sample 603B-29-1, 57-62 cm: Santonian. A rich and diverse

microplankton assemblage was recovered from this sample. The strati-graphically significant species are:

Senoniasphaera rotundata (Plate 2, Fig. 1) and 5. protrusa (Plate2, Fig. 2). S. rotundata appears in the lower part of the Turonianstratotype (Foucher, 1982) and in the Coniacian of Canada (Bujakand Williams, 1978). S. protusa appears in the middle Santonianof France (Foucher, 1979) and in the Turonian of Canada (Bujakand Williams, 1978).

1145


0

10

20

30

40

50

60

S 70E

I 80o

90

100

110

120

130

140

150

Figure 5dard

5YR 4/4

N7

N9N 7

5YR 4/4

N 9 •

5YR 4/4

5Y6/45YR 4/4

10GY5/2-10YR 5/6 •10GY 5/2 '5YR 4/4

.10GY5/2.

5YR4/4

•10YR6/6

10GY 5/2

10YR6/6

10GY5/2

_

-

ε

Φ _

ager

c "B

-

-

1 0Y 6/2 .

5Y 7/6_ 10Y 6/2 _— 5Y 7/6 - '— 10Y 6/2 -

5Y 7/6

10Y 6/2

5Y 7/6

10Y 6/2

— 5Y7/6—.

10Y 6/2 •

BN1

10Y 4/2

10Y 4/2

10Y4/2

N1

10Y6/6

10Y4/2

10Y 4/2

.Lithological description of Sections 105-9-2 to 105-9-6 (Cenomanian/Turonian Boundary Event). Stan-color coding noted on column.

Dinogymnium euclaense and Coronifera striolata (Plate 2, Fig. 5)first occur in the Santonian of Canada (Bujak and Williams, 1978).

After the CTBE was recognized from the enrichmentin type II organic matter in the samples issued from theOrganic Geochemistry Panel and that recognition con-firmed by the ages just given the break between the Hat-teras and Plantagenet Formations (Core 603B-34) wassampled specifically for a detailed study of the organiccontent and nature of the organic matter along the CTBE.This study shows the advent of the anoxic environmentduring the CTBE and the cyclic influences of anoxia,more and more favorable to the preservation of marineorganic matter, from the bottom to the top of Core603B-34 (i.e., between 1136.5 and 1127.5 m).

In Core 34, 19 sedimentary sequences were determinedon the basis of the sedimentological descriptions (Fig. 8)and results on geochemical data (Fig. 9). These sequenc-es are named Sequences A to S and may be subdividedinto two or more subunits, one labeled by odd numbers(Al, A3, Bl, Cl, etc.) corresponding to the dusty yel-low-green 5GY 5/2 claystones with greyish yellow greenlaminations 5GY 7/2, and one labeled by even numbers(A2, A4, B2, C2, etc.), corresponding to the laminatedblack claystones. In the following description we studythe sequences stratigraphically, from the bottom of Core603B-35 to the top of Core 603B-34. The sequences aredevoid of any variations in the carbonate content (Fig.9). Whatever the lithology (green or dark claystones),the CaCO3 content is less than 10 wt.% with an average

content of 5, except in Sample 603B-34-3, 118-119 cm,where it reaches 21 (Table 3).

In Core 603B-35 the alternations of black shales fromthe Hatteras Formation contain mainly type III organicmatter (see the detailed study of Sample 6O3B-35-3, 74-76 cm). The petroleum potential is medium to good (2.15to 8.36 kg (HC/t of rock) in the richer sample, wherethe hydrogen indices range from 105 to 217 mg HC/gTOC. At the bottom of Core 603B-34, the green clay-stones Al of sequence A) are very poor in TOC (<0.2wt.%). The sequence is bimodal, with two slight enrich-ments in TOC: 0.7 wt.% in A2 and 1.04 to 1.79 wt.% inA4; both contain an organic matter of type III origin.The sequences above B, C, and D, have very thin, darklevels (B2 = 2 cm, C2 = 4 cm, D2 = 8 cm), but theyare richer in TOC (2.06 to 5.29 wt.%), with a petroleumpotential ranging from 3.6 to 18.1 kg HC/t of rock. Thehydrogen indices are often higher than 300 and even reach354 mg HC/g TOC in Sample 603B-34-5, 82-83 cm, in-dicating a greater ratio of marine organic matter and/orless degradation than in the underlying dark claystones.This pattern extends to sequences E and F, where thedark claystones are again thicker (E2 = 36 cm, F2 =54 cm). The TOC contents reach 7.7-7.8 wt.% at thetop of the sequences, corresponding to a petroleum po-tential near 30 kg HC/t of rock. The hydrogen indicesare also a slightly higher, about 380 mg HC/g TOC. Se-quence G is different because of the bioturbated levels(G3 and G5) on both sides of dark claystones (G4), where

1146


Table 2. Carbonate, organic carbon, and pyrolysis data in the Cenomanian/Turonian Boundary Event, Sections 105-9-2 to105-9-6.

Core-Section(level in cm)

9-2, 239-2, 589-2, 1009-2, 1159-2, 140

Plantagenet Fm. 9-3, 249-3, 449-3, 579-3, 679-3, 949-3, 109

9-3, 1009-3, 1119-3, 1129-3, 1139-3, 1149-3, 1189-3, 1209-3, 1219-3, 1229-3, 1239-3, 1259-3, 1269-3, 1289-3, 1329-3, 1349-3, 1359-3, 1389-3, 1399-3, 1459-3, 1479-3, 1499-3, 1509-4, 29-4, 79-4, 109-4, 119-4, 119-4, 129-4, 139-4, 169-4, 23

Cenomanian/Turonian 9-4, 25Boundary Event 9-4, 25

9-4,299-4, 369-4, 399-4, 439-4, 529-4, 539-4, 589-4, 629-4, 699-4, 709-4, 739-4, 799-4, 809-4, 829-4, 839-4, 869-4, 879-4, 889-4, 899-4, 939-4, 1039-4, 1069-4, 1139-4, 1189-4, 1209-4, 1319-4, 1329-4, 1389-4, 1419-4, 1429-4, 148

Sub-bottomdepth (m)

287.73288.08288.50288.65288.90289.24289.44289.57289.67289.94290.09

290.10290.11290.12290.13290.14290.18290.20290.21290.22290.23290.25290.26290.28290.32290.34290.35290.38290.39290.45290.47290.49290.50290.52290.57290.60290.61290.61290.62290.63290.66290.73290.75290.78290.79290.86290.89290.93291.02291.03291.08291.12291.19291.20291.23291.29291.30291.32291.33291.36291.37291.38291.39291.43291.53291.56291.63291.68291.70291.81291.82291.88291.91291.92291.98

Mineralcarbon (%)

0.63j]

]•

;

(

]]

1.321.261.501.201.35).681.441.801.500.8"

2.521.500.001.741.200.961.112.462.221.381.741.680.961.501.201.560.000.000.120.040.271.080.781.201.500.870.121.980.042.041.680.961.111.801.561.921.441.500.781.261.261.980.840.000.000.240.000.300.720.420.360.540.540.840.510.510.780.761.021.741.321.440.871.02

CaCO3

(%)

511101210116

1215127

21120

141089

20181114148

1210130010296

101271

160

171489

15131612126

10101670020263344744668

14111278

TOC(%)

0.350.240.190.220.190.220.160.160.220.150.14

1.324.405.59

10.317.690.723.649.836.910.27

15.2012.5812.6815.490.22

12.520.15

11.6112.6117.100.277.87

12.7821.07

8.280.270.327.099.709.55

13.300.110.376.116.484.88

10.184.810.179.37

13.784.640.29

13.921.26

14.6223.809.18

11.960.162.380.180.072.750.100.150.090.270.146.576.673.930.420.14

Si + S 2(kg HC/t rock)

3.742.372.272.662.232.310.041.862.481.701.16

1.545.186.61

24.9411.700.888.14

35.3522.30

1.0254.6745.5543.8559.800.86

42.251.27

42.7050.5559.99

1.1527.1545.2581.5024.15

1.230.09

21.1038.7336.2049.700.870.91

18.6024.1511.5529.459.800.70

28.1548.6511.150.64

49.801.07

54.2574.1337.6536.750.965.861.040.804.920.880.910.810.260.83

19.5016.159.050.750.79

HI

89104117225140107204327292

330331312353

309

335364340

309323348264

265399343340

219281337210259174

274321213

32966342301373280

214

158

275217202155

OI

15390986274

133717178

58686663

56

667751

84675674

69286966

2707891686480

675679

6019866529769

89

98

849073

269

T1 max

411417410412410407410411413

411412410409

412

410410405

413411408411

414412412410

417416412416410415

413411414

410404411398409410

413

412

418412419419

1147


Table 2 (continued).


9-5,49-5, 59-5, 79-5, 149-5, 189-5, 219-5, 229-5, 239-5, 469-5, 659-5, 669-5, 679-5, 759-5, 799-5, 809-5, 899-5, 939-5, 949-5, 1199-5, 1279-5, 1289-5, 1309-5, 1329-5, 1349-5, 1379-5, 138

Hatteras Fm. 9-5, 1449-5, 1509-6, 19-6, 39-6, 399-6, 409-6, 419-6, 649-6, 699-6, 759-6, 789-6, 829-6, 879-6, 909-6, 919-6, 1069-6, 1119-6, 1149-6, 1169-6, 1179-6, 1229-6, 1259-6, 1309-6, 1359-6, 1419-6, 1449-6, 150

Sub-bottomdepth (m)

292.04292.05292.07292.14292.18292.21292.22292.23292.46292.65292.66292.67292.75292.79292.80292.89292.93292.94293.19293.27293.28293.30293.32293.34293.37293.38293.44293.50293.51293.53293.89293.90293.91294.14294.19294.25294.28294.32294.37294.40294.41294.56294.61294.64294.66294.67294.72294.75294.80294.85294.91294.94295.00

Mineralcarbon (%)

0.901.741.262.221.740.901.920.961.081.141.801.261.922.041.112.161.041.260.660.781.081.200.870.721.020.750.870.901.080.961.081.561.021.081.501.110.871.320.870.600.630.720.400.720.540.600.420.360.600.480.630.920.78

CaCO3

(%)

7141018147

16899

151016179

189

10569

10768677989

1389

1297

11755636453354586

TOC(%)

0.118.24

10.216.564.640.213.520.420.110.133.400.202.621.720.503.224.290.130.160.184.543.240.243.120.720.410.181.010.780.310.284.140.250.148.580.242.519.470.194.780.180.164.037.297.427.360.167.030.236.330.231.601.79

Si + S2(kg HC/t rock)

0.8725.4525.9014.609.361.415.661.290.911.077.450.843.953.020.765.126.940.671.461.297.555.051.333.751.351.160.991.242.782.231.695.901.671.20

18.301.623.00

16.201.116.251.291.023.13

12.3012.4011.551.009.920.987.021.021.781.90

HI

284230197183

145226

193

126158134133158

142134

117150232

103(324)

121

192

84156

108

73152150138

130

100

8483

OI

68586365

56126

49

4680605065

5045

666495

51(49)

47

57

5053

54

83494849

62

59

7876

Tmax

417416415413

419387

433

429425442426419

425427

428436424

500(589)

431

418

407417

422

413417417417

417

418

407416

Note: Parentheses indicate doubtful data.

the TOC content is often lower than 1 wt.% and the hy-drogen indices lower than 50 mg HC/g TOC. Becauseof the bioturbated area, the trend of sequence G is sym-metrical, and the highest TOC content is reached in themiddle of G4 (Samples 603B-34-4; 56-57 cm: TOC =6.5 wt.%, S! + S2 = 26.54 kg HC/t of rock, and HI =390 mg HC/g TOC). In sequences H and K (sequences Iand J being undeveloped), the TOC contents increaseagain: 9.12 wt.°7o in H2 (Sample 603B-34-3, 148-149 cm)and 11.45 wt.% in K2 (Sample 603B-34-3, 88-89 cm),corresponding respectively to petroleum potentials of39.13 and 52.90 kg HC/t of rock and hydrogen indicesof 404 and 442 mg HC/g TOC. The thicker sequencesof black shales in Core 34 correspond to sequences L to

R, where the green claystones are often very reduced. Insequences L to O the TOC content increases to 14 wt.%,corresponding to a petroleum potential of 68 kg HC/tof rock and to hydrogen indices close to 500 mg (HC/gTOC. The highest geochemical results are obtained insequences P and Q, that is, in Sample 603B-34-1, 124-125 cm (P2): TOC = 17.98 wt.<K>, S! + S2 = 96.05 kgHC/t of rock, and HI = 507 mg HC/g TOC in Sample6O3B-34-1, 82-83 cm (Q2), TOC = 20.40 wt.<Fo, andSi + S2 = 104.30 kg HC/t of rock. The highest hydro-gen index belongs to Sample 603B-34-1, 90-91 cm, withHI = 525 mg HC/g TOC (Fig. 9, Table 3). In overlyingsequences R and S, the enrichment decreases, since inR2 the TOC content is about 14.26 wt.%, S! + S2 =

1148


£ 1

-9-c oJ3α O

13 (1) CO

CO D O

TOC

0 100 0 5 10 15 20 25

288-

289

290

291

292

293

294

295

Sections 3 and 4 Sections 5 and 6

800

700

600-

500

J 400-

300-

Section 5 at 93 cm:upper Cenomanian

200-

100-

100 200 100Oxygen index (mg CO2/g TOC)

200

Figure 6. Organic carbon content and characterization of the organic matter by pyrolysis method for the Cenomanian/Turonian Boundary Event inSections 105-9-2 to 105-9-6.

67.04 kg HC/t of rock, and HI = 440 mg HC/g TOC,and in S2, TOC content = 8.25 wt.%, Si + S2 = 33.75 kgHC/t of rock, and HI = 387 mg HC/g TOC.

Some of the sequences are symmetrical, with a prog-gresive increase in TOC enrichment, one or two maxima(depending on the sequence), and then a progressive de-crease. For example, sequences M and R have one maxi-mum, whereas sequences L and N have two (Fig. 9). Othersequences show an asymmetric variation of the TOC witha progressive increase but a sharp passage toward thegreen claystone of the following sequence. For example,the transition between sequences H and I occurs over2 cm, with a decrease from 8.88 wt.% (Sample 603B-34-3,138-139 cm) to 0.06 wt.% (Sample 603B-34-3, 136-137cm) (Table 2). Such sharp transitions characterize thetop of various sequences (E, F, H, L) (Fig. 9). The hy-drogen indices fluctuate in the same way, with one ortwo maxima often higher than 400 mg HC/g TOC (se-

quences L to R), indicating better preservation of ma-rine organic matter in Core 34 (Figs. 9-10).

CONCLUSIONS

The Cretaceous formations in Hole 603B can be char-acterized by the organic carbon content, the petroleumpotential, and the type of organic matter.

In the Blake-Bahama Formation the samples richerin TOC (2.63 wt.%) have medium petroleum potential(4.35 kg HC/t of rock). The same content is reached inthe black claystones of the Hatteras Formation, wherethe higher TOC content is about 3.43 wt.%, correspond-ing to medium petroleum potential (5.01 kg HC/t ofrock). In these two formations the organic matter is typeIII and is quite immature (above the oil window).

The break between the Hatteras and Plantagenet for-mations (Core 34) corresponds to the Cenomanian/Tu-ronian Boundary Event (CTBE), which is dated by di-

1149


Ag

e

Santonian

early Turon.late Cenom.

Cenomanian

early Cenom.Vraconian

Cor

e-S

ecti

on(l

evel

in

cm

)

29-1,57

33, CC(1)

34-1,82

34-3, 70

34-5, 23

Dinoflagellate cysts

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ides

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Figure 7. Stratigraphic distribution of selected dinoflagellate species in Hole 603B.

Or

10 -

20 µ

30

40

50

60

<n

3 70Φ

E

1 8°o

90

100

110

120

130

140

150Figure 8

603B

Q2

Q1

P2

P1

Dark claystones

Bioturbated area

Green claystones

Lithological description of sequences A to S, corresponding to the Cenomanian/Turonian Boundary Event in Sections 603B-34-1 to34-6.

1150


TOC (%)

10

HI (mg HC/g TOC)

20 0 100 200 300 400 500 600

= . (33.CC)

«̂_ lower Turonian —upper Cenomaπian

Cenomanian(34-3, 70 cm)

lower Cenomanian —uppermost Albian/Vraconian(34-5, 23 cm)

Figure 9. Vertical distribution of the organic carbon and carbonate content in the Cenomanian/TuronianBoundary Event at Site 603 (sequences A to S, Sections 603B-34-1 to 603B-34-6).

1151


Table 3. Carbonate, organic carbon, and pyrolysis data in the Cenomanian/Turonian Boundary Event,Sample 6O3B-33,CC; Sections 603B-34-1 to 603B-34-6 and 603B-35-1 to 6O3B-35-4.

SedimentarySequence

S2

SI

Rl

Q2

Qi


33-0, 134-1, 034-1, 234-1, 434-1, 634-1, 834-1, 1034-1, 1234-1, 1434-1, 1634-1, 1834-1, 2034-1, 22

34-1, 2434-1, 2634-1, 2834-1, 3034-1, 3234-1, 3434-1, 3634-1, 3834.1, 4234-1, 4034-1, 4434-1, 4634-1, 4834-1, 5034-1, 5234-1, 5434-1, 5634-1, 5834-1, 60

34-1, 6234-1, 6434-1, 6634-1, 6834-1, 7034-1, 7234-1, 7434-1, 7634-1, 7934-1, 8034-1, 8134-1, 8234-1, 8434-1, 8634-1, 8834-1, 9034-1, 9234-1, 9434-1, 96

34-1, 9834-1, 10034-1, 10234-1, 10434-1, 10634-1, 10834-1, 11034-1, 11234-1, 11434-1, 11634-1, 11834-1, 12034-1, 12234-1, 12434-1, 12634-1, 12834-1, 13034-1, 13234-1, 13434-1, 13634-1, 13834-1, 14034-1, 14234-1, 144

Sub-bottomdepth (m)

1127.491127.501127.521127.541127.561127.581127.&)1127.621127.641127.661127.681127.701127.72

1127.741127.761127.781127.801127.821127.841127.861127.881127.901127.901127.941127.961127.981128.001128.021128.041128.061128.081128.10

1128.121128.141128.161128.181128.201128.221128.241128.261128.281128.301128.311128.321128.341128.361128.381128.401128.421128.441128.46

1128.481128.501128.521128.541128.561128.581128.601128.621128.641128.661128.681128.701128.721128.741128.761128.781128.801128.821128.841128.861128.881128.901128.921128.94

Mineralcarbon (%)

0.660.940.781.020.620.860.470.670.950.710.710.630.39

0.270.370.780.780.460.540.620.700.380.620.380.620.540.620.620.620.670.190.15

0.550.430.460.700.620.540.780.380.460.700.461.020.460.700.620.860.540.430.17

0.550.660.540.620.300.460.300.540.300.380.380.460.140.220.781.100.430.230.270.430.310.310.350.31

CaCO3(%)

5868574686653

2366445635354555621

5446546346484657441

554524242334126942243333

TOC(%)

4.587.078.258.208.137.560.340.430.141.010.190.280.34

1.361.668.549.219.0810.1010.7710.9012.9112.4611.8412.6214.2610.909.208.775.782.090.37

1.604.4911.4013.2413.248.3410.708.987.628.068.83

20.4018.7216.7413.3816.7010.473.930.72

3.695.966.907.496.888.057.119.5711.0711.5512.5012.6115.9117.9817.238.543.073.303.473.703.633.923.703.94

Si + S 2

15.2728.1133.7529.7830.0528.810.510.780.880.580.370.730.59

1.971.37

33.2637.1538.7539.6842.3943.1256.2552.6851.5957.8767.0452.1340.3937.6830.952.090.27

1.8014.6955.7970.3159.6033.2044.2230.7429.2234.2639.06104.3099.9091.7072.4093.2249.3212.260.49

8.3523.5626.5829.9824.0232.4918.8237.4249.5954.2657.6956.8981.5296.0590.5534.166.808.2910.2610.459.9612.4811.3812.96

HI

324374387337342350(124)(121)

45(147)(207)(121)

126733673814023653643704063944094304404454104013428949

10131046149642335938934035539141048550351750652544229251

214372364376326380248368424442436425486507500378205238282266257304287312

OI

313337455258

(276)(195)

73(232)(136)(91)

605132322725221823132421173134363865141

402928303146383633373926363337344153119

3542454455405851494641514851535210872687842455351

T1 max

420412411407409407(414)(406)

418(432)(423)(408)

410412409409410408406407406406405406405406405405408405427

409413406407408408408409412411411412410408408408409411399

413413411410413412410411411411412410409408409412413418414412409408410409

1152



Sedimentary

Sequence

r> 1rl

mVJZ

O1

M l

rsj

i>Z

MlINI

\Λ*>M Z

Core-Section

(level in cm)

34-1, 146

34-1, 148

34-2, 0

34-2, 2

34-2, 4

34-2, 6

34-2, 8

34-2, 10

34-2, 12

34-2, 14

34-2, 16

34-2, 18

34-2, 20

34-2, 22

34-2, 24

34-2, 26

34-2, 28

34-2, 30

34-2, 32

34-2, 34

34-2, 36

34-2, 38

34-2, 40

34-2, 42

34-2, 44

34-2, 46

34-2, 48

34-2, 50

34-2, 52

34-2, 54

34-2, 56

34-2, 58

34-2, 60

34-2, 62

34-2, 64

34-2, 66

34-2, 68

34-2, 70

34-2, 72

34-2, 74

34-2, 76

34-2, 78

34-2, 80

34-2, 82

34-2, 84

34-2, 86

34-2, 88

34-2, 90

34-2, 92

34-2, 94

34-2, 96

34-2, 98

34-2, 100

34-2, 102

34-2, 104

34-2, 106

34-2, 108

34-2, 110

34-2, 112

34-2, 114

34-2, 116

34-2, 118

34-2, 120

34-2, 122

34-2, 124

34-2, 126

34-2, 128

34-2, 130

34-2, 132

34-2, 134

34-2, 136

34-2, 138

34-2, 140

34-2, 142

34-2, 144

34-2, 146

Sub-bottom

depth (m)

1128.96

1128.98

1129.00

1129.02

1129.04

1129.06

1129.08

1129.10

1129.12

1129.14

1129.16

1129.18

1129.20

1129.22

1129.24

1129.26

1129.28

1129.30

1129.32

1129.34

1129.36

1129.38

1129.40

1129.42

1129.44

1129.46

1129.48

1129.50

1129.52

1129.54

1129.56

1129.58

1129.60

1129.62

1129.64

1129.66

1129.68

1129.70

1129.72

1129.74

1129.76

1129.78

1129.80

1129.82

1129.84

1129.86

1129.88

1129.90

1129.92

1129.94

1129.96

1129.98

1130.00

1130.02

1130.04

1130.06

1130.08

1130.10

1130.12

1130.14

1130.16

1130.18

1130.20

1130.22

1130.24

1130.26

1130.28

1130.30

1130.32

1130.34

1130.36

1130.38

1130.40

1130.42

1130.44

1130.46

Mineral

carbon (%)

0.27

0.27

0.62

0.54

0.54

0.46

0.54

0.62

0.62

0.38

0.15

0.27

0.59

0.43

0.59

0.31

0.59

0.35

0.59

0.71

0.67

0.55

0.67

0.86

0.00

0.54

0.22

0.54

0.54

0.31

0.70

0.67

0.83

0.23

0.23

0.94

0.54

0.54

0.54

0.30

0.62

0.54

1.26

1.02

0.78

1.02

0.86

0.86

0.54

0.62

0.70

0.78

0.62

0.38

0.27

0.35

0.38

0.79

1.02

1.02

0.78

0.62

0.14

0.86

0.86

1.26

0.54

1.10

0.38

0.46

0.54

0.70

0.86

0.55

0.55

0.43

CaCO3

(%)

22

544445531254

5353566567042443667228444254108687745665323

378865177104934467554

TOC(<%)

0.93

0.67

11.27

12.35

13.86

8.72

7.16

8.05

9.56

13.32

0.15

0.21

0.22

0.22

0.63

0.90

1.46

0.58

0.37

0.85

3.30

4.44

3.96

5.00

5.72

5.98

5.67

5.52

6.58

4.13

5.14

3.94

4.23

1.19

3.31

6.28

6.54

5.98

7.00

7.59

7.34

5.63

11.09

8.71

5.54

8.66

12.71

6.87

7.51

7.90

6.44

6.00

7.47

1.47

0.35

0.58

4.26

4.35

7.29

7.35

6.09

5.80

6.09

7.04

8.88

9.76

7.58

14.58

12.82

11.29

11.08

8.22

5.16

4.39

3.05

3.38

Si + S2

1.24

1.04

58.76

59.26

74.25

37.40

30.93

33.63

40.59

67.96

0.25

0.33

0.40

0.46

0.68

0.86

2.00

0.64

1.09

0.67

8.58

14.47

11.96

17.60

23.06

25.33

23.86

23.44

27.36

14.52

19.27

16.56

13.09

0.68

6.18

29.98

27.88

23.86

28.06

31.92

30.88

22.62

59.14

39.04

24.18

38.96

62.64

28.30

30.36

33.90

23.94

22.70

32.13

1.79

0.15

0.47

13.28

14.84

32.00

36.28

29.44

24.10

24.46

29.92

39.02

45.74

34.44

68.39

60.82

52.72

53.17

37.99

21.34

17.20

10.56

5.88

HI

105107

497457509406399391398485(113)

(110)

(100)

(141)

817911983

(205)

6025031128933637739838939439133236039529549163453401379377394401374506424406422466387379399346363407993164

299325416470457387377398415438422437451441454435382354321163

OI

113124

38324910798792833

(1113)

(571)

(559)

(273)

12110088155(154)

9443495739465872653073534343159592020211918162013152014121716154446491059159

3337434954644253505058455356485651658080

Tmax

410405

411409409413414413412408(443)

(416)

(450)

(432)

414419421412(402)

411418416417415413415412410411412412413412412411416412411412411413412409410411410409412412411411415409418440410

415415411413413410410412410410413410411409410413409410410411

1153



SedimentarySequence


Sub-bottomdepth (m)

Mineralcarbon (%)

CaCO3 TOCS + S2 HI OI

Ml

r oLz

T 1

LI

VI

Kl

JI

12

T 11 1

34-2, 148

34-3, 0

34-3, 2

34-3, 4

34-3, 6

34-3, 8

34-3, 10

34-3, 12

34-3, 1434-3, 16

34-3, 18

34-3, 20

34-3, 22

34-3, 2434-3, 26

34-3, 28

34-3, 30

34-3, 32

34-3, 3434-3, 36

34-3, 38

34-3, 40

34-3, 42

34-3, 4434-3, 46

34-3, 48

34-3, 50

34-3, 52

34-3, 5434-3, 56

34-3, 58

34-3, 60

34-3, 62

34-3, 6434-3, 66

34-3, 68

34-3, 70

34-3, 71

34-3, 7234-3, 74

34-3, 76

34-3, 78

34-3, 80

34-3, 8234-3, 84

34-3, 86

34-3, 8834-3, 90

34-3, 92

34-3, 94

34-3, 96

34-3, 9834-3, 100

34-3, 102

34-3, 104

34-3, 106

34-3, 10834-3, 110

34-3, 112

34-3, 11434-3, 116

34-3, 118

34-3, 120

34-3, 122

34-3, 124

34-3, 12634-3, 128

34-3, 130

34-3, 132

34-3, 134

34-3, 136

1130.48

1130.501130.52

1130.54

1130.56

1130.58

1130.60

1130.62

1130.64

1130.66

1130.68

1130.70

1130.72

1130.741130.76

1130.78

1130.80

1130.82

1130.84

1130.86

1130.88

1130.90

1130.92

1130.941130.96

1130.98

1131.00

1131.02

1131.041131.06

1131.08

1131.10

1131.12

1131.14

1131.16

1131.18

1131.20

1131.21

1131.221131.24

1131.26

1131.28

1131.30

1131.321132.34

1131.36

1131.381131.401131.42

1131.44

1131.46

1131.481131.50

1131.52

1131.54

1131.56

1131.581131.60

1131.62

1131.641131.66

1131.68

1131.70

1131.72

1131.74

1131.761131.78

1131.80

1131.82

1131.84

1131.86

0.71

0.39

0.55

0.47

0.63

0.07

0.19

0.94

0.620.38

0.54

1.02

0.38

0.380.22

0.30

0.30

0.30

0.190.23

0.19

0.23

0.35

0.350.47

0.43

0.43

0.43

0.860.46

0.38

0.62

1.02

0.460.30

0.62

0.84

0.62

0.700.38

0.38

0.07

0.43

0.430.19

0.23

0.620.19

0.000.07

0.43

0.110.15

0.23

0.99

0.43

0.000.00

0.27

0.27

0.39

2.58

0.00

0.15

0.00

0.270.11

0.15

0.47

0.310.27

6354512

85348332222222233444474358425756331442

2520141128400

2232101

0211432

4.34

4.00

3.99

1.49

0.49

0.50

0.70

7.15

5.037.15

8.52

7.49

7.48

5.27

5.485.27

6.66

8.98

4.585.18

5.78

5.86

4.88

3.463.53

4.10

4.37

3.45

6.42

7.16

7.78

11.58

9.78

14.4010.68

10.50

10.71

10.2612.21

9.50

6.79

0.290.54

1.000.18

2.21

11.450.70

1.38

1.52

4.47

1.45

0.750.21

0.10

0.26

0.17

0.18

0.86

0.760.94

1.193.31

0.32

2.950.27

0.11

0.13

0.08

0.05

0.06

11.62

10.10

13.02

1.16

0.32

0.280.37

30.54

20.27

29.79

39.64

30.85

29.85

22.8622.52

21.34

24.03

39.32

16.84

14.59

20.07

21.47

16.39

9.8212.44

16.27

15.52

10.79

29.59

25.30

32.50

55.20

48.55

67.0043.85

47.15

43.34

42.80

63.00

42.90

28.350.57

0.72

0.820.55

4.35

52.902.12

2.76

3.96

13.70

3.04

0.92

0.21

0.20

0.17

0.50

0.12

0.46

0.320.62

1.07

7.09

0.74

5.760.22

0.090.07

0.06

0.09

0.05

25323831574554846

404378394437390373407382376337415341263322338317272333371331288433335398453464440390429390396490429396(145)7467

(139)

18344218117120428715389529027

(176)

44

48346086203(178)

1834427838

(120)

33

65425194719653

41534843334259493950636831252432201232151930394441374445414047424754

(197)

13065

(444)

484142112817548191100167220162(659)

128

3334303163

(206)

4581145460

(60)

100

412413415419411410409

414413414410413411411412414412414412408411409410414415412410410410409409410408406410410415411410411412(407)

383414(348)

414407339411411414410409367380367342375

412415414415414(388)

40640540700

(348)

440

34-3,

34-3,34-3,

138140142

1131.88

1131.901131.92

0.54

0.300.30

422

8.88

7.82

6.93

36.58

29.0620.56

393355280

345056

409409409

1154



Sedimentary

SequenceCore-Section

(level in cm)Sub-bottomdepth (m)

Mineralcarbon (%)

TOC

Si + S 2HI OI

H2

π 1

O 1

/~i c

U J

G4

G3

c* 1OI

F">rZ

34-3, 144

34-3, 146

34-3, 148

34-4, 0

34-4, 2

34-4, 4

34-4, 6

34-4, 8

34-4, 10

34-4, 12

34-4, 14

34-4, 16

34-4, 18

34-4, 20

34-4, 22

34-4, 24

34-4, 26

34-4, 28

34-4, 30

34-4, 32

34-4, 34

34-4, 36

34-4, 38

34-4, 40

34-4, 42

34-4, 44

34-4, 46

34-4, 48

34-4, 50

34-4, 52

34-4, 54

34-4, 56

34-4, 58

34-4, 60

34-4, 62

34-4, 64

34-4, 66

34-4, 68

34-4, 70

34-4, 72

34-4, 74

34-4, 76

34-4, 78

34-4, 80

34-4, 82

34-4, 84

34-4, 86

34-4, 88

34-4, 90

34-4, 92

34-4, 94

34-4, 96

34-4, 98

34-4, 100

34-4, 102

34-4, 104

34-4, 106

34-4, 108

34-4, 110

34-4, 112

34-4, 114

34-4, 116

34-4, 118

34-4, 120

34-4, 122

34-4, 124

34-4, 126

34-4, 128

34-4, 130

34-4, 132

34-4, 134

34-4, 136

34-4, 138

34-5, 0

34-5, 2

34-5, 4

1131.94

1131.96

1131.98

1132.00

1132.02

1132.04

1132.66

1132.08

1132.10

1132.12

1132.14

1132.16

1132.18

1132.20

1132.22

1132.24

1132.26

1132.28

1132.30

1132.32

1132.34

1132.36

1132.38

1132.40

1132.42

1132.44

1132.46

1132.48

1132.50

1132.52

1132.54

1132.56

1132.58

1132.60

1132.62

1132.64

1132.66

1132.68

1132.70

1132.72

1132.74

1132.76

1132.78

1132.80

1132.82

1132.84

1132.86

1132.88

1132.90

1132.92

1132.94

1132.96

1132.98

1133.00

1133.02

1133.04

1133.06

1133.08

1133.10

1133.12

1133.14

1133.16

1133.18

1133.20

1133.22

1133.24

1133.26

1133.28

1133.30

1133.32

1133.34

1133.36

1133.38

1133.50

1133.52

1133.54

0.70

0.30

0.38

0.46

0.39

0.31

0.47

0.47

0.51

0.31

0.51

0.79

0.00

0.59

0.63

0.63

0.63

0.67

0.59

0.71

0.75

0.63

0.67

0.75

0.63

0.67

0.55

0.47

0.59

0.63

0.35

0.78

0.70

0.70

0.38

0.70

0.78

0.78

0.62

0.54

0.43

0.47

0.47

0.55

0.71

0.71

0.67

0.59

0.75

0.63

0.51

0.59

0.55

0.71

0.55

0.47

0.43

0.43

0.35

0.39

0.62

0.30

0.35

0.38

0.38

0.30

0.54

0.62

0.22

0.06

0.38

0.19

0.70

0.63

0.11

0.51

6

2

3

4

3

3

4

4

4

3

4

7

0

5

5

5

5

6

5

6

6

5

6

6

5

6

5

4

5

5

3

6

6

6

3

6

6

6

5

4

4

4

4

5

6

6

6

5

6

5

4

5

5

6

5

4

4

4

33

5

2

3

3

3

2

4

5

2

0

3

2

6

5

1

4

7.06

8.35

9.12

6.67

4.15

2.68

2.98

2.80

1.67

1.430.14

0.27

0.10

0.28

0.53

0.93

1.99

0.37

0.84

0.91

0.94

0.42

0.70

0.96

4.04

3.47

3.68

3.44

2.80

2.53

4.41

6.50

4.49

5.01

6.05

5.83

4.91

5.26

4.15

4.29

1.211.22

1.30

1.30

1.48

0.51

0.93

0.84

0.33

0.40

0.27

0.53

0.33

0.27

0.09

0.07

0.82

0.86

0.24

0.28

7.15

4.78

2.68

7.70

5.76

6.80

6.79

6.84

5.21

5.60

5.81

4.45

6.05

2.83

2.08

2.78

28.86

31.73

39.13

23.83

12.86

6.43

7.99

8.71

1.96

1.570.13

0.09

0.29

0.17

0.47

0.46

5.39

0.24

0.51

0.46

0.52

0.19

0.49

0.53

9.80

7.16

11.66

9.36

5.16

4.60

10.99

26.54

11.82

15.78

21.90

22.16

15.70

17.94

12.00

12.06

1.02

1.18

1.16

1.08

1.05

0.14

0.43

0.45

0.12

0.14

0.09

1.00

0.14

0.17

0.09

0.13

0.60

0.60

0.23

0.20

26.54

16.84

6.40

31.52

11.89

20.96

23.29

28.26

17.14

19.18

17.80

14.02

21.44

6.26

2.60

6.02

388

360

404

336

292

224

258

294

107

101

71

22

(210)

50

74

40

260

59

49

43

46

33

47

45

232

196

301

257

175

171

234

390

247

296

344

366

306

323

276

269

78

90

83

78

64

14

35

36

18

20

11

19

18

37

44

(114)

5958

71

57

353

334

226

388

195

291

322

387

307

321

287

295

332

207

114

203

47

47

40

49

66

91

50

43

57

67

193

107

(270)

64

40

44

36

57

30

38

45

62

59

54

41

47

48

49

56

58

51

43

50

50

42

50

52

49

58

57

79

67

63

65

27-

35

26

33

24

38

48

28

33

15

111

(171)

17

33

63

4

29

34

33

31

65

46

54

47

71

48

56

92

66

108

87

81

412

412

409

411

414

415

414

411

416

413

459

375

(393)

410

412

409

415

412

409

412

410

410

405

408

417

418

416

413

418

416

409

413

409

411

412

411

411

409

409

410

419

421

420

421

420

402

413

411

401

404

322

398

340

408

328

(3491

14

412

417

416

406

410

414

410

413

412

414

410

411

414

411

412

412

416

411

414

1155



SedimentarySequence


Sub-bottomdepth (m)

Mineralcarbon (%)

TOCSi + S2 HI OI

Fl

E2

El

34-5, 634-5, 834-5, 1034-5, 1234-5, 1434-5, 1634-5, 18

34-5, 2034-5, 2234-5, 2334-5, 2434-5, 2634-5, 2834-5, 3034-5, 3234-5, 3434-5, 3634-5, 3834-5, 4034-5, 4234-5, 4434-5, 4634-5, 4834-5, 5034-5, 5234-5, 5434-5, 5634-5, 5834-5, 6034-5, 6234-5, 64

34-5, 6634-5, 6834-5, 7034-5, 72

1133.561133.581133.601133.621133.641133.661133.68

1133.701133.721133.731133.741133.761133.781133.801133.821133.841133.861133.881133.901133.921133.941133.961133.981134.001134.021134.041134.061134.081134.101134.121134.14

1134.161134.181134.201134.22

0.510.390.470.190.230.310.19

0.940.940.901.020.780.781.100.940.780.310.510.550.550.941.020.590.940.860.310.230.390.590.430.07

0.390.460.700.51

4342232

887866986345588587323541

3464

3.374.733.681.271.341.230.93

5.254.907.795.835.684.783.514.844.732.561.971.461.524.264.912.743.914.871.300.220.370.230.180.34

2.064.605.292.53

8.7814.4410.941.561.501.481.38

18.0917.2628.8621.9420.1315.1313.6917.7216.865.263.242.302.2313.9017.887.4213.3316.161.270.260.280.210.310.42

3.6415.1318.194.99

24128527911010110771

32433035535333729937434834119315214713631235125832731785916878

(133)65

169314328189

697198905746159

39373047707449363257463539343439384082218138139(100)100

52464856

412410410418420417359

415414416414415416419419419418417413415414418415413415412423450476(441)382

418410410417

Dl34-5, 7434-5, 7634-5, 78

1134.241134.261134.28

0.430.310.15

0.350.260.41

0.190.260.24

437746

177258168

424401410

C2

Cl

34-5, 80_34-5,_82_

34-5, 8434-5, 86

1134.301134.321134.34'1134.36

0.300.460.310.23

4.014k63_0.720.50

12.46_17_.00_

0.580.40

300354

6958

5147

140108

411411415"405

B2

bl

A A

34-5, 8834-5, 9034-5, 9234-5, 9434-5, 9634-5, 9834-5, 10034-5, 10234-5, 10434-5, 10634-5, 10834-5, 11034-5, 11234-5, 11434-5, 11634-5, 11834-5, 12034-5, 12234-5, 124

34-5, 12634-5, 12834-5, 13034-5, 13234-5, 13434-5, 13634-5, 13834-5, 14034-5, 14234-5, 144

1134.381134.401134.421134.441134.461134.481134.501134.521134.541134.561134.581134.601134.621134.641134.661134.681134.701134.721134.74

1134.761134.781134.801134.821134.841134.861134.881134.901134.921134.94

1.100.430.430.510.670.630.590.590.670.590.710.590.670.950.630.710.790.830.59

0.710.670.390.430.350.390.390.590.670.55

94446555656 (56 (8 (567 (7 • (

5 (

663433356

1.883.423.153.233.133.163.103.213.223.123.133.163.163.183.223.113.09).12).ll

1.291.70.04.27.21.19.36.79.13

5 0.82

17.130.230.190.240.170.220.120.190.240.110.130.190.200.170.190.060.070.080.13

0.801.520.640.840.720.881.021.480.520.54

33936

(107)836269603836676275

(106)565036331764

54825054516457774151

46176(173)148277238320148168283262238(250)10010511878117182

45445038514238424459

412407(453)468382393357321321383359469(475)4314053620

318455

422424419416418421418426420408

34-5,34-5,34-6,

1461480

1134.961134.981135.00

0.590.670.67

566

0.510.450.31

0.300.300.35

473152

515377

418399379

1156



Sedimentary

Sequence

A3

A Λ

A.Z

Al

Core-Section

(level in cm)

34-6, 2

34-6, 4

34-6, 6

34-6, 8

34-6, 10

34-6, 12

34-6, 14

34-6, 16

34-6, 18

34-6, 20

34-6, 24

34-6, 26

34-6, 28

34-6, 30

34-6, 32

34-6, 34

34-6, 36

34-6, 38

34-6, 40

34-6, 42

34-6, 44

34-6, 46

34-6, 48

35-1, 17

35-1, 26

35-1, 50

35-1, 70

35-1, 78

35-1, 113

35-2, 11

35-2, 24

35-2, 98

35-3, 3

35-3, 14

35-3, 44

35-3, 74

35-3, 75

35-3, 129

35-3, 149

35-4, 9

35-4, 38

35-4, 53

35-4, 86

35-4, 118

35-0, 16

Sub-bottom

depth (m)

1135.02

1135.04

1135.06

1135.08

1135.10

1135.12

1135.14

1135.16

1135.18

1135.20

1135.24

1135.26

1135.28

1135.30

1135.32

1135.34

1135.36

1135.38

1135.40

1135.42

1135.44

1135.46

1135.48

1136.67

1136.76

1137.00

1137.20

1137.28

1137.65

1138.11

1138.24

1138.98

1139.53

1139.64

1139.94

1140.24

1140.25

1140.79

1140.99

1141.09

1141.38

1141.53

1141.86

1142.18

1142.66

Mineral

carbon (%)

0.55

0.59

0.47

0.51

0.47

0.47

1.11

0.31

0.63

0.51

0.47

0.67

0.75

0.59

0.59

0.51

0.43

0.63

0.63

0.55

0.55

0.39

0.59

0.39

0.31

0.35

0.23

0.31

0.55

0.43

0.15

0.31

0.83

0.19

0.11

0.69

0.47

0.43

0.39

0.79

0.79

0.63

0.83

0.51

0.75

CaCθ3

(%)

554444935446655445555353332354137216443775746

TOC(%)

0.24

0.44

0.34

0.46

0.36

0.26

0.73

0.74

0.19

0.30

0.14

0.13

0.10

0.17

0.13

0.15

0.16

0.12

0.11

0.11

0.10

0.08

0.38

0.59

1.01

1.65

3.70

1.86

1.27

1.20

1.10

0.96

0.49

0.96

0.84

2.74

2.43

1.17

0.71

0.40

0.65

0.97

0.76

0.95

0.88

Si + S2

0.21

0.33

0.33

0.36

0.16

0.19

0.37

0.39

0.17

0.59

0.20

0.17

0.13

0.29

0.09

0.17

0.15

0.18

0.13

0.11

0.17

0.13

0.35

0.43

0.59

0.98

8.36

2.15

0.68

0.60

0.92

0.68

0.10

0.80

0.74

5.01

3.30

0.48

0.38

0.20

0.21

0.36

0.28

0.75

0.32

HI

425576523658404268

(147)

8685

(110)

65547356757355

(120)

(100)

58475053217105464573651671621771263?45302228226322

OI

83551006767817053116(203)

93115(170)

11877931007564100(210)

(150)

61515241424948404754314332991302231856042464753

Tmax

333411407405425413406404402(361)

378385

(411)

324393370337361356334(387)

(401)

397392416422422420414423423424407420408430428416415359403411402416391

Note: Parentheses indicate doubtful data.

noflagellate cysts in the kerogen fraction. In Hole 603Bthe CTBE is composed of 19 sequences. At the bottomof the core (sequence A), the origin of the organic mat-ter is identical to that of the underlying Hatteras Forma-tion (terrestrial organic matter). However, the maximumTOC content reached in the sequences gradually increaseswith the petroleum potential and the hydrogen index.Each new sequence reaches higher values than the un-derlying one, up to sequence Q (Section 1, between 62and 94 cm).

In Site 105, only 68 n. mi. farther southeast, the CTBEis thinner (only 1.5 m) but the maximum TOC content isthe same (up to 25 wt.%).

The CTBE is not a single, homogeneous, black shalelayer, but appears to be a condensation of several thinlevels, richer and richer in organic matter of type II ori-gin, interbedded with thinner levels of green claystones.The alternation is identical to that of the Hatteras For-mation, but in the CTBE preservation of organic matterof marine origin is better, indicating the presence of an

anoxic environment just before the multicolored clay-stones in the Plantagenet Formation were deposited.

The spreading of the CTBE off the American conti-nental margin (Sites 105 and 603) shows that the phe-nomenon previously recognized off the African and Eu-ropean continental margins (Sites 135, 137, 138, 367, 398,and 551) is not restricted to the eastern North Atlantic.In addition, this type of sediment has even been observedon the continental margin of Venezuela in the La Lunaand Querecual formations (Hedberg, 1937, 1950), whereit is an effective source rock. The CTBE seems to be ageneral feature, not a local one, of the North and SouthAtlantic oceans and the Tethys (Thurow and Kuhnt, inpress; Herbin, Montadert, et al., in press; Herbin, Mül-ler, et al., in press).

No simple explanation can be given for the phenome-non. The initial factor could be the acceleration of sea-floor spreading, with an increase in tectono-magmaticprocesses on the ridge and consequently a rise of the sealevel according to Boer's model (1983). However, it has

1157

oO

ooOoOoOOO

% TOC0-0.150.16-0.300.31-0.500.51-1.001.01-1.501.51-2.00

2.01-3.00

3.01-4.00

4.01-5.00

5.01-10.00

10.01-15.00

> 15.00

800

XW?üCO

Zm

100 100 100 0 100

Oxygen index (mg CO2/g TOC)

100 100

Figure 10. Characterization of the type of organic matter by pyrolysis method in the Cenomanian/Turonian Boundary Event at Site 603 (Sequences A to S, Sections 603B-34-1 to 603B-34-6and 603B-35-1 to 603B-35-6). Size of the circles is proportional to total organic carbon.


not been truly settled whether the anoxic, deep oceanwaters acted as an active trap or whether a relative in-crease in organic productivity in the ocean, too high forslow ocean water circulation, induced anoxia in deep wa-ter. But the hypothesis of high productivity is not trulyin accordance with the low rate of sedimentation, andthe reason that the ocean became more or less globallyanoxic before the Plantagenet Formation was depositedstill remains to be determined.

ACKNOWLEDGMENTS

The authors are indebted to Dr. George Claypool of the U.S. Geo-logical Survey, Dr. Dean A. Dunn of the University of Southern Mis-sissippi, and Drs. Warren S. Drugg and Robert W. Jones of the Chev-ron Oil Field Research Laboratory for comments upon and review ofthe present paper.

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Chénet, P. Y., and Francheteau, J., 1979. Bathymetric reconstructionmethod: application to the Central Atlantic Basin between 10°Nand 40°N. In Donnelly, T., Francheteau, J., Bryan, W., Robinson,P., Flower, M., Salisbury, M., et al., Init. Repts. DSDP, 51, 52,53, Pt. 2: Washington (U.S. Govt. Printing Office), 1501-1514.

Cookson, I. C , and Hughes, N. F., 1964. Microplankton from theCambridge Greensand (mid-Cretaceous). Palaeontology, 7:37-59.

Davey, R. J., 1969. Non-calcareous microplankton from the Cenoma-nian of England, northern France and North America; Part 1. Bull.Brit. Mus. (Nat. Hist.), Geol., 7:103-180.

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Espitalié, J., Marquis, F., and Barsony, I., 1984. Geochemical log-ging. In Voorhees, K. J. (Ed.), Analytical Pyrolysis Techniques andApplications: London (Butterworth), pp. 276-304.

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Foucher, J. C , 1979. Distribution stratigraphique des kystes de Dinofla-gellés et des Acritarches dans le Crétracé supérieur du Bassin deParis et de 1'Europe septentrionale. Palaeontographica, Abt. B,169:78-105.

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Lancelot, Y., Hathaway, J. C , and Hollister, C. D., 1972. Lithologyof sediments from the Western North Atlantic, Leg XI, Deep SeaDrilling Project. In Hollister, C. D., Ewing, J. I., et al., Init. Repts.DSDP, 11: Washington (U.S. Govt. Printing Office), 901-950.

Lentin, J. K., and Williams, G. L., 1981. Fossil Dinoflagellates: Indexto Genera and Species (1981 Ed.). Bedford Inst. Oceangr. Rept.,Bl-R-81-12.

Manum, S., and Cookson, I. C , 1964. Cretaceous microplankton in asample from Graham Island, Arctic Canada, collected during thesecond "Fram" Expedition (1898-1902). With notes on microplank-ton from the Hassel Formation, Ellef Ringnes Island. Schrift.Norske Videnskaps-Akad. Oslo, I. Mat-Naturv. Klasse, Ny Sen,17:1-35.

Masure, E., 1984. Uindice de diversité et les dominances des "commu-nautés" de kystes de Dinoflagellés: marqueurs bathymétriques;forage 398D, croisiére 47B. Bull. Soc. Géol. France, 7eme Ser.,

Morgan, R., 1978. Albian to Senonian Palynology of Site 364, AngolaBasin. In Bolli, H. M., Ryan, W. B. F., et al., Init. Repts. DSDP,40: Washington (U.S. Govt. Printing Office), 915-951.

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Roucaché, J., Deroo, G., and Boulet, R., 1979. Caractérisation pardifférentes méthodes physico-chimiques de types de matiére organ-ique dans des sediments du Crétacé d'Atlantique en mer profonde.Rev. Inst. Franc. Pet., 34(2): 191-220.

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Date of Initial Receipt: 21 February 1985Date of Acceptance: 7 November 1985

APPENDIXPalynomorph Species

Achomosphaera triangulata (Gerlach, 1961) Davey and Williams, 1969Adnatosphaeridium apenninicum Corradini, 1972 (Plate 2, Fig. 8)Callaisophaeridium asymmetricum (Deflandre and Courteville, 1939)

Davey and Williams, 1966Chatangiella manumii (Vozzhennikova, 1967) Lentin and Williams,

1976 (Plate 2, Fig. 3)Chatangiella sp. (Plate 2, Fig. 7)Chichaouadinium vestitum (Brideaux, 1971) Bujak and Davies, 1983

(Plate 1, Fig. 12)Coronifera striolata (Deflandre, 1937) Stover and Evitt, 1978 (Plate 2,

Fig. 5)Coronifera oceanica Cookson and Eisenack, 1958Cyclonephelium distinctum Deflandre and Cookson, 1955Cyclonephelium hughesii Clarke and Verdier, 1967 (Plate 1, Fig. 8)Cyclophelium membraniphorum Cookson and Eisenack, 1962 (Plate

1, Fig. 5)Cyclonephelium vannophorum Davey, 1969Dinogymnium acuminatum Evitt et al., 1967 (Plate 1, Fig. 7)Dinogymnium euclaense Cookson and Eisenack, 1970Dinopterygium cladoides Deflandre, 1935

Dissiliodinium globulum Drugg, 1978Epelidosphaeridia spinosa (Cookson and Hughes, 1964) Davey, 1969

(Plate 1, Fig. 1)Exochosphaeridium bifidum (Clarke and Verdier, 1967) Clarke et al.,

1968Exochosphaeridium phragmites Davies et al., 1966Florentinia cooksoniae (Singh, 1971) Duxbury, 1980Florentinia radiculata (Davey and Williams, 1966) Davey and Verdier,

1973Florentinia resex Davey and Verdier, 1976 (Plate 1, Fig. 11)Heierosphaeridium heteracanthum (Deflandre and Cookson, 1955)

Eisenack and Kjellström, 1971Hystrichodinium pulchrum Deflandre, 1935Hystrichosphaeridium palmatum (White, 1842 ex Brown, 1848) Dow-

nie and Sarjeant, 1965Isabelidinium sp.Kiokansium polypes (Cookson and Eisenack, 1962) Below, 1982Kleithriasphaeridium loffrense Davey and Verdier, 1976Litosphaeridium siphonophorum (Cookson and Eisenack, 1958) Da-

vey and Williams, 1966 (Plate 1, Fig. 2)Odontochitina costata Alberti, 1961 (Plate 1, Fig. 3)Odontochitina operculata (O. Wetzel, 1933) Deflandre and Cookson,

1955Odontochitina porifera Cookson, 1956 (Plate 2, Fig. 4)Oligosphaeridium complex (White, 1842) Davey and Williams, 1966Oligosphaeridium dictyophorum (Cookson and Eisenack, 1958) Da-

vey and Williams, 1969Ovoidinium ovale (Cookson and Eisenack, 1970) Lentin and Williams,

1976 (Plate 1, Fig. 4)Palaeohystrichophora infusorioides Deflandre, 1935 (Plate 1, Fig. 9)Palaeoperidinium cretaceum Pocock, 1962Polysphaeridium ambiguum (Deflandre, 1937) Yun, 1981Pterospermella australiensis (Deflandre and Cookson, 1955) Eisenack,

1972Psaligonyaulax deflandrei Sarjeant, 1966Rottnestia borussica (Eisenack, 1954) Cookson and Eisenack, 1961

(Plate 2, Fig. 6)Senoniasphaera protrusa Clarke and Verdier, 1967 (Plate 2, Fig. 2)Senoniasphaera rotundata Clarke and Verdier, 1967 (Plate 2, Fig. 1)Spinidinium lanternum Cookson and Eisenack, 1970 (Plate 2, Fig. 9)Spiniferites ancoriferum Cookson and Eisenack, 1974Spiniferites cingulatus ssp. cingulatus (O. Wetzel, 1933) Lentin and

Williams, 1973Spiniferites crassipellis (Deflandre and Cookson, 1955) Sarjeant, 1970Spiniferites ramosus ssp. multibrevis (Davey and Williams, 1966) Len-

tin and Williams, 1972Subtilisphaera cheit Below, 1981 (Plate 1, Fig. 6)Surculosphaeridiumi longifurcatum (Firtion, 1952) Davey et al., 1966Tanyosphaeridium variecalamum Davey and Williams, 1966Trichodinium castenea (Deflandre, 1935) Clarke and Verdier, 1967Trithyrodinium suspectum (Manum and Cookson, 1964) Davey, 1969

(Plate 1, Fig. 13)Tubulospinosa oblongata Davey, 1970Wallodinium sp.Xenascus ceratioides (Deflandre, 1937) Lentin and Williams, 1973Xiphophoridium alatum (Cookson and Eisenack, 1962) Sarjeant, 1966

Cyst. A (Plate 1, Fig. 10)

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Plate 1. 1. Epelidosphaeridia spinosa (Cookson and Hughes, 1964) Davey, 1969. Sample 603B-34-5, 23 cm. Slide no. 2, position England FinderGraticule (EFG): Q54, width 45 µm. 2. Litosphaeridium siphonophorum (Cookson and Eisenack, 1958) Davey and Williams, 1966. Sample 603B-34-5, 23 cm. Slide no. 2, position EFG: Q33-34, width 52 µm. 3. Odontochitina costata Alberti, 1961. Sample 603B-34-5, 23 cm. Slide no. 1,position EFG: K51, width 61 µm, height 100 µm. 4. Ovoidinium ovale (Cookson and Eisenack, 1970) Lentin and Williams, 1976. Sample603B-34-5, 23 cm. Slide no. 2, position EFG: E57, height 55 µm, width 36 µm. 5. Cydonephelium membraniphorum Cookson and Eisenack,1962. Sample 603B-34-3, 70 cm. Slide no. 3, position EFG: Q33, width 77 µm. 6. Subtilisphaera cheit Below, 1981. Sample 603B-34-3, 70 cm.Slide no. 4, position EFG: S36, height 56 µm, width 50 µm. 7. Dinogymnium acuminatum Evitt et al., 1967. Sample 603B-34-3, 70 cm. Slideno. 5, position EFG: XY41, height 54 µm, width 30 µm. 8. Cydonephelium hughesii Clarke and Verdier, 1967. Sample 603B-34-5, 23 cm. Slideno. 3, position EFG: WX56-57, height 74 µm, width 68 µm. 9. Palaeohystrichophora infusorioides Deflandre, 1935. Sample 603B-34-3, 70cm. Slide no. 1, position EFG: N45-46, height 42 µm, width 35 µm. 10. Cyst A. Sample 603B-34-3, 70 cm. Slide no. 1, position EFG: F50,width 43-40 µm. 31 archeopyle with quadra 2a. 11. Florentinia resex Davey and Verdier, 1976. Sample 6O3B-33CC (1 cm). Slide no. 3, positionEFG; S46, height 45 µm, width 50 µm. 12. Chichaouadinium vestitum (Brideaux, 1971) Bujak and Davies, 1983. Sample 603B-33.CC, (1 cm).Slide no. 3, position EFG: V40, width 40 µm. I3Pa archeopyle. 13. Trithyrodinium suspectum (Manum and Cookson, 1964) Davey, 1969. Sam-ple 6O3B-33.CC (1 cm). Slide no. 2, position EFG: TU41-42, height 51 µm, width 45 µm.

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8

Plate 2. 1. Senoniasphaera rotundata Clarke and Verdier, 1967. Sample 603B-29-1, 57 cm. Slide no. 1, position EFG: CD49, height 63 µm, endo-cyst diameter 45 µm. 2. Senoniasphaera protrusa Clarke and Verdier, 1967. Sample 603B-29-1, 57 cm. Slide no. 2, position EFG: GH34, height60 µm, endocyst height 45 µm, width 50 µm. 3. Chatangiella manumii (Vozzhennikova, 1967) Lentin and Williams, 1976. Sample 603B-29-1,57 cm. Slide no. 2, position EFG: B42, height 60 µm, width 45 µm, endocyst diameter 40 µm. 4. Odontochitinaporifera Cookson, 1956. Sam-ple 603B-29-1, 57 cm. Slide no. 1, position EFG: L53-54, endocyst diameter 73 µm. 5. Coronifera striolata (Deflandre, 1937) Stover and Evitt,1978. Sample 603B-29-1, 57 cm. Slide no. 2, position EFG: NO40, height 75 µm, width 70 µm, endocyst diameter 46 µm. 6. Rottnestia borussi-ca (Eisenack, 1954) Cookson and Eisenack, 1961. Sample 603B-29-1, 57 cm. Slide no. 1, position EFG: X33, height 62 µm, width 45 µm. 7.Chatangiella sp. Sample 603B-29-1, 57 cm. Slide no. 1, position EFG: UV38-39, height 64 µm, width 47 µm. 8. Adnatosphaeridium apennini-cum Corradini, 1972. Sample 603B-29-1, 57 cm. Slide no. 2, position EFG: M45-3, endocyst diameter 50 µm, processus height 23-25 µm, width3-4 µm. 9. Spinidinium lanternum Cookson and Eisenack, 1970. Sample 603B-29-1, 57 cm. Slide no. 1, position EFG: UV38-39, height55 µm, width 30 µm.

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