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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
J. P. HERBIN, E. MASURE, J. ROUCACHE
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
Table 2 (continued).
Core-Section(level in cm)
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
£ 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
J. P. HERBIN, E. MASURE, J. ROUCACHE
Ag
e
Santonian
early Turon.late Cenom.
Cenomanian
early Cenom.Vraconian
Cor
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ecti
on(l
evel
in
cm
)
29-1,57
33, CC(1)
34-1,82
34-3, 70
34-5, 23
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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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
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
Core-Section(level in cm)
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
Table 3 (continued).
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
Table 3 (continued).
SedimentarySequence
Core-Section(level in cm)
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
Table 3 (continued).
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
J. P. HERBIN, E. MASURE, J. ROUCACHE
Table 3 (continued).
SedimentarySequence
Core-Section(level in cm)
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
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
Table 3 (continued).
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.
ORGANIC GEOCHEMISTRY OF CRETACEOUS FORMATIONS, SITE 603
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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Herbin, J. P., Deroo, G., and Roucaché, J., 1983. Organic geochemis-try in the Mesozoic and Cenozoic formations of Site 534, Leg 76,Blake-Bahama Basin, and comparison with Site 391, Leg 44. InSheridan, R. E., Gradstein, F. M., et al., Init. Repts. DSDP, 76:Washington (U.S. Govt. Printing Office), 481-493.
Herbin, J. P., Montadert, L., Müller, C , Gomez, R., Thurow, J., andWiedmann, J., in press. Organic-rich sedimentation at the Ceno-manian/Turonian boundary in oceanic and coastal basins in theNorth Atlantic and Tethys. Summerhayes, C , and Shackleton, N.J. (Eds.), North Atlantic Palaeoceanography. Geol. Soc. London,Spec. Publ.
Herbin, J. P., Müller, C , Graciansky, P. C. de, Jacquin, T., Magniez,F., and Unternehr, P., in press. Cretaceous anoxic events in theSouth Atlantic. Evoluçaáo do Atlántico Sul no Mesozoico, IX Con-gresso Brasileiro de Paleontologia, Boletin Técnico da Petrobras.
Hue, A. Y., Durand, B., and Monin, J. C , 1978. Humic compoundsand kerogens in cores from Black Sea sediments, Leg 42B, Holes379A, B, and 38OA. In Ross, D. A., Neprochnov, Y. P., et al., Init.Repts. DSDP, 42, Pt. 2: Washington (U.S. Govt. Printing Office),737-748.
Ikan, R., Baedecker, M. J., and Kaplan, I. R., 1975a. Thermal altera-tion experiments on organic matter in recent marine sediment. IIIsoprenoids. Geochim Cosmochim. Acta., 39:187-194.
, 1975b. Thermal alteration experiments on organic matterin recent marine sediment. Ill Aliphatic and steroidal alcohols.Geochim. Cosmochim. Ada., 39:195-203.
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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Müller, C , Schaff, A., and Sigal, J., 1983. Biochronostratigraphie desformations d'áge Crétacé dans les forages du DSDP dans 1'OcéanAtlantique Nord. Rev. Inst. Franc. Pet., 38(6): 683-708, 39(l):3-23.
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.
Sever, J., Parker, P. L., 1969. Fatty alcohols (normal and isoprenoid)in sediments. Science, 164:1052-1054.
Simoneit, B. R. T., 1973. Appendix I: The identification of isopre-noidal ketones in Deep Sea Drilling Project core samples and theirgeochemical significance. In Burns, R. E., Andrews, J. E., et al.,Init. Repts. DSDP, 21: Washington (U.S. Govt. Printing Office),909-931.
Thurow, J., and Kuhnt, W., in press. Mid-Cretaceous of the GibraltarArch Area—organic-carbon-rich sediments, faunal patterns, pa-laeoenvironment. An attempt to continue off-shore to on-shoreoutcrops. In Summerhayes, C , and Shackleton, N. J. (Eds.), NorthAtlantic Palaeoceanography. Geol. Soc. London, Spec. Publ.
Tissot, B., Deroo, G., and Herbin, J. P., 1979. Organic matter in Cre-taceous sediments of the North Atlantic. Talwani, M., Hay, W.,Ryan, W. B. F. (Eds.), Deep Drilling Results in the Atlantic Ocean.Am. Geophys. Un., Maurice Ewing Series, 3:362-374.
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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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