30. organic geochemistry of cenozoic and mesozoic ... · cenozoic and mesozoic sediments ranging in...

30. ORGANIC GEOCHEMISTRY OF CENOZOIC AND MESOZOIC SEDIMENTS FROM DEEPSEA DRILLING SITES 544 TO 547, LEG 79, EASTERN NORTH ATLANTIC1

G. Deroo, J. P. Herbin, and J. Roucaché, Institut Français du Pétrole, Paris2

ABSTRACT

Cenozoic and Mesozoic sediments ranging in age from Pleistocene to Early Jurassic/late Triassic were recovered onDSDP Leg 79, off Morocco at Sites 544 to 547 in front of the Mazagan Plateau. The main zone of oil genesis should bereached at Site 547 within the Jurassic section. Organic material of marine origin with good petroleum potential charac-terizes the late Eocene slumps of Site 547 and originates from reworked organic matter of Cretaceous origin. Organicenrichment also occurs at Site 545 during the middle to late Albian period. Since the organic matter appears to be au-tochthonous, reducing environments of deposition are inferred. In the other Cretaceous deposits, variably altered or-ganic matter of the same origin predominates. Finally, a transect including Site 370 off the Agadir Canyon, is studied:detrital organic matter and reducing environments of deposition were more developed during Albian time for Site 370than for Site 545.

INTRODUCTION

During Leg 79, a series of holes were drilled near theMazagan Plateau to document the rifting and the subsi-dence of a passive margin bordering the early Atlantic(Fig. 1). Neogene foraminiferal and nannofossil oozeswere drilled on all sites. From the northwest to the south-east, they respectively overlie a Jurassic salt sequence atSite 546, Jurassic limestones at Site 544, Paleogene sili-ceous nannochalk and claystone punctuated by debrisflows at Site 547, and Cenomanian nannofossil clay-stone at Site 545. At Sites 545 and 547, Cretaceous nan-nofossil claystone deposits of Cenomanian to Aptianage were replete with slumps, pebbles, and microfaultswhich in turn overlie limestone, dolomite, and sandymudstone of Jurassic age.

The present study characterizes geochemically the or-ganic matter in the sedimentary rocks penetrated onDSDP Leg 79. Two sets of samples were obtained: (1)271 samples of a few grams each were collected while onthe cruise; (2) 29 larger samples were provided by theOrganic Geochemistry Panel.

This paper consists of two parts, the first part com-posed of five sections. The first three sections of partone are devoted to mineral and organic carbon analysesand the pyrolysis of organic matter. The third sectionconsiders maturation, petroleum potential, and the na-ture of organic matter, respectively. In these sections,the description follows the drilling order, from top tobottom, through every lithological unit for each site.The fourth and fifth sections concern kerogen and chlo-roform extract studies on some selected samples. In parttwo, the vertical distribution of organic matter and therelated environments of deposition are examined for theEarly to mid-Cretaceous sections of Sites 545 and 547

34°N

32°

Hinz, K., Winterer, E. L., et al., Init. Repts. DSDP, 79: Washington (U.S. Govt. Print-ing Office).

2 Address: Institut Français du Pétrole, B.P. 311,92503 Rueil Malmaison Cedex, France.

12°W 10°

figure 1. Location of DSDP Leg 79.

and are compared with a similar section at Site 370.Tables 1-5 are contained in the Appendix to this chapter.

METHODOLOGY

Organic carbon was determined for 300 acid-treated samples witha LECO apparatus. A pyrolysis assay was conducted on equivalentsamples by Rock-Eval (Espitalié et al., 1977). Seventeen samples wereselected to be extracted with chloroform. Ten of these samples wereanalyzed by gas chromatography of saturate hydrocarbons. Kerogenconcentrates were prepared (Hue et al., 1978) and elemental analysisperformed on the same ten samples.

721

G. DEROO, J. P. HERBIN, J. ROUCACHE

RESULTS

Mineral Carbon and Carbonates

Site 544

A large carbonate fraction (58-80 wt.% of CaCo3equivalent) occurs in the clayey foraminiferal-nanno oozeof Unit I for Holes 544A and 544B (Fig. 2, AppendixTable 1). The carbonate content slightly increases fromtop to bottom, i.e., from Pleistocene to late Miocene inHole 544B. In Hole 544A no samples were provided fromUnits II and III and the only sample obtained from Ju-rassic Unit IV was carbonate-poor (15.3%) and belongedto the muddy sand lithofacies.

Site 545

The clayey foraminiferal-nanno ooze in Subunit IAof Pleistocene age reveals 30-60% carbonates against60% or more in Subunit IB (Cores 10 to 20). Higher val-ues in the latter are probably due to the presence oflimestone pebbles and cobbles. The same carbonate con-tent is found for the foram-nanno chalk of Unit II (Cores20 to 27) except toward the bottom where the contentdecreases to 37% (Fig. 3, Appendix Table 2).

The carbonate content for the clayey facies of Sub-unit IIIA (Cores 28 to 44) is 30% and less but withmany high values (up to 60%) due to pebbles in Cores34 to 44. Along Subunit IIIB (Cores 45 to 55) where per-vasive microfaults and folds are observed throughout,the carbonate distribution suggests a series of carbonatesequences with the values decreasing in each from 50-70%at the bottom to 40% at the top. A 50% content isfound in Subunit IIIC (Sections 545-55-6 to 545-56-7).For all of Unit III, carbonate content increases downhole from 20% at the top to 60% at the bottom.

Site 546

Within the nanno ooze and the foraminiferal-nannoooze of Unit I, Pleistocene to late Miocene in age, arange of values from 40 to 77% was observed (Fig. 4,

Appendix Table 3). The lithofacies of Unit II includestwo different ranges: (1) 15-33% for the grayish redclaystone and (2) 63-76% for the greenish and reddishbrown calcareous claystone. Low values of 13 and 14%correspond to the gypsiferous sandy claystone at thebottom of Unit II.

Site 547

As observed for Site 545, the Pleistocene part of theclayey nannofossil ooze in Unit I contains less than 60%of carbonates compared with 60-80% for both the Plio-cene-Miocene part and the foram-nanno ooze of Sub-unit IIA (Fig. 5, Appendix Table 4). About 40% is foundfor the nannofossil clay of Subunit IIB. A 60-80%range recurs for the conglomeratic clayey Unit III andfor the chalk facies of Subunit IVA. A 41-56% contentcharacterizes the clayey facies of the same subunit. How-ever, 44-74% of carbonates were found in Subunit IVBexcept on both ends where the contents fall between 21and 31%. Units I-IV have carbonate contents of 60%or more, which is high when compared to Unit V.

Unit V is 30% at the top but increases downward to60% near the bottom and is composed of claystone andcalcareous claystone with subordinate pebbly to cobblyclaystone and mudstone. Unit V can be subdivided intothree parts: (1) an upper part, from Cores 547A-40 to517A-66 with carbonate contents ranging from 21 to45%, with the richer contents of 30% or more found incores where pebbly layers occur; (2) a middle part, inCores 547A-67 to 547A-72 with a higher range of valuesfrom 46 to 72%; and (3) a lower part, from Core 547A-73 to 547B-5 where the contents fall to 37% or less.The limestone and claystone sequence of Unit VI wasnot sampled. Beneath it, the red and gray sandy mud-stone of Unit VII includes carbonate contents that rangefrom 14 to 36%.

Summary

For Sites 544, 545, 546, and 547, a carbonate-poorfacies characterizes the Pleistocene and a carbonate-rich

Ages

Neogene

JurassicIII

IVA

1 -

-100

EquivalentCaCθ3(wt.%)

Totalorg. carbon

(wt.%)

Hydrogenindex

Oxygenindex

Petroleumpotential(S1+S2)kgHC/

trock0 30 60 1000 1 2 3 4 5 0 200 400 600 0 200 400 0 2 4 6 8 10 400 420 440

Age

Neogene1 - 0

1 2 - 3 8


Totalorg. carbon

(wt.%)

PetroleumHydrogen Oxygen potential

index index (S1+S2)

kgHC/

trock

0 30 60 100 0 1 2 3 4 5 0 200 400 600 0 200 400 0 2 4 6 8 10 400 420 440

Figure 2. Vertical distribution of carbon and pyrolysis assay data, Holes 544A and 544B.

722

ORGANIC GEOCHEMISTRY OF CENOZOIC AND MESOZOIC SEDIMENTS

Ages

Neogene

Cenomanianto

late Aptian

Jurassic

f i

IA

IB

IIIA

IIIB

i

1-0

10-

20-

28-

34-

45-

100

-200

-300

400

-500


Totalorg. carbon

(wt.%)

Hydrogenindex

0 30 60 100 0 1 2 3 4 5 0 200 400 600 0 200 400 0 2 4 6 8 10 400 420 440

Figure 3. Vertical distribution of carbon and pyrolysis assay data, Hole 545.

Ages

Neogene

in

15-

1--0

-100


Totalorg. carbon

(wt.%)

Hydrogenindex

Oxygenindex

Petroleumpotential(S1+S2)kgHC/t rock

200 4000 2 4 6 8 10 400 420 440

TMAX

Figure 4. Vertical distribution of carbon and pyrolysis assay data, Hole 546.

(60% or more) facies characterizes the Pliocene-Mio-cene section. In the underlying Cretaceous sections coredin Holes 545, 547A, and 547B, the carbonate-poor (15to 44%) facies corresponds to the Cenomanian rockswhereas some high (up to 60%) carbonate values occurin the Albian section. Sequences with carbonate con-tents increasing down hole are observed for the late Ap-tian at Site 545 while low carbonate values were foundfor the Jurassic sampled at the bottom of Hole 547B.

Organic Carbon

The distribution of total organic carbon contents ob-served in the holes may be classified as follows: veryrich, more than 3 wt.%; rich, 1.01 to 3.00 wt.%; aver-age, 0.51 to 1.00 wt.%; low, 0.21 to 0.50 wt.%; andvery low, 0.20 wt.% and less.

Site 544

Very low to low organic carbon contents occur forUnit I in both Hole 544A (0.09-0.21%) and Hole 544B(0.07-0.28%) and in Unit IV of Hole 544A (0.13%)(Fig. 2, Appendix Table 1).

Site 545

Very low organic carbon content (0.14-0.19%) char-acterizes Units I and II except for the slightly richer

clayey facies of Subunit IA and at the bottom of Unit II(0.28-0.77%) (Fig. 3, Appendix Table 2). In Unit III,most samples of Subunit IIIA (Cores 28 to 45) reveal acontent of 1.0% or more, and richer levels (1.94-4.46%)characterize the lower part of the subunit. Low to aver-age contents (0.37-0.70%) are observed throughout Sub-unit IIIB (Sections 545-45-1 to 545-55-6) and the richestorganic contents correspond to the lowest carbonate con-tents. Very low organic contents (0.09-0.24%) are foundalong Subunit IIIC (Sections 545-55-6 to 545-56-7).

Site 546

As previously observed in Sites 544 and 545, Unit Ireveals very low contents of organic carbon (0.07-0.23%)except at the top and at the bottom where low contentsoccur (0.25-0.32%). Low contents (0.27-0.41%) are al-so found for the gypsiferous levels of Unit II. (Fig. 4,Appendix Table 3)

Site 547

Very low to low organic carbon contents (0.10-0.50%)characterize Units I and II (Fig. 5, Appendix Table 4).Rich and very rich levels (2.28-3.11 %) occur in Unit III.Within Unit IV, very low to low organic carbon contents(0.10-0.44%) are observed with a slight increase at thetop and bottom (0.62-0.66%). Within Unit V, a pro-

723


Ages

Neogene

Paleogene toLate

Cretaceous

Cenomanianto

late Albian

Jurassic

Early Jurassic/late Triassic

I I

IIA

IVΛ

IVB

VIA

VIB

VII

A1-

23-

32

39

B6-

14

-100

-200

-300

-400

-500

- 6 0 0

- 7 0 0

- 8 0 0

-900

EquivalentCaC03(wt.%)

Totalorg. carbon

(wt.%)

Hydrogenindex

Oxygenindex

Petroleumpotential(S1+S2)kgHC/

t rock

TMAX

0 30 60 100 0 1 2 3 4 5 0 200 400 600 0 200 4000 2 4 6 810 400 420 440i

I

F

F

I

|

m-•M •r

[_

5

=

-

ill 1

i

i

•i

••

r-1 -

• k .

=

Figure 5. Vertical distribution of carbon and pyrolysis assay data, Holes 547A and 547B.

gressive enrichment is observed downward, from 0.50%in Core 547A-41 to 1.49% in Core 547B-5 at the bot-tom. In the latter part, many low values or impoverish-ments, presumably related to carbonate pebbly materi-al, disturb that trend.

Given the average of the analyses performed on board,rich and very rich levels (0.63-6.76%) characterize UnitVI. In Unit VII, the organic carbon content varies from0.44% to 0.07% at the bottom.

Summary

For the several holes analyzed, a negative correlationbetween carbonate content and organic carbon contentwas observed along the Cenozoic series, except for theEocene slumps of Unit III in Hole 547A where organiccarbon poor and organic carbon rich samples are bothfound in carbonate-rich material. Such a correlation isagain observed for the Albian and Aptian deposits ofHole 545 within Unit III (Cores 34 to 55) and for Holes547A and 547B within Unit V (Cores 547A-58 to 547B-5).

Pyrolysis of Organic Matter

Maturation

Method

During the pyrolysis of organic matter by Rock-Eval,the temperatures reached at the maximum of hydrocar-bon production (TMAX) for peak S2 depend both on

the stage of maturation and the nature of the organicmatter (Espitalié and Deroo, in press). The TMAX canbe plotted against hydrogen indices (Fig. 6, 7) to esti-mate the maturation of samples. Evolution paths forthe three reference types of organic matter (types I, II,and III) are outlined in the figures. When maturationincreases, hydrogen indices decrease; however the pyrol-ysis temperatures (TMAX) also increase. The variationfollows the trend of the evolution paths. Isoreflectancecurves (0.5, 1.0, 1.5) superimposed on the graph can becompared with the maturation scale compiled from oth-er studies using vitrinite reflectance data (Espitalié etal., in press). Isoreflectance curve 0.5 defines the bound-ary between immature and mature organic matter. Itroughly corresponds to TMAX in the 430-435°C rangefor organic materials of types II and III. The area be-tween curves 0.5 and 1.0 defines the "oil window," i.e.,the zone where the main genesis of liquid hydrocarbonsoccurs. Following curve 1.0 the zone for the formationof condensate and wet gas is found and following curve2.0, dry gas (Espitalié and Deroo, in press).

Results

The first requirement for using the TMAX data is anorganic carbon content of more than 0.20%. The sec-ond requirement depends on the Production Index (PI)of pyrolysis (Espitalié et al., 1977) i.e., the ratio of freehydrocarbons (peak SI) to total hydrocarbons (peaks SI+ S2) expelled during pyrolysis (Appendix Tables 1-5).

724


900

800

700

600

•S 500

400

300

200

100

350 400 450

- Maximum temperature of pyrolysis (°C)-

500

Figure 6. Hydrogen indices versus pyrolysis peak temperatures(TMAX), Site 545.

Thus, the TMAX for the shallow buried organic materi-al, which corresponds to an anomalously large PI of0.25 + due to a high number of natural organic mole-cules in the SI peak and to a low organic carbon content(<0.20%), will be disregarded (Figs. 2-5).

Site 544

There are no significant TMAX data for Holes 544Aand 544B (Appendix Table 1).

Site 545

The ranges of TMAX observed along the hole are asfollows: 420-421 °C at the bottom of the Neogene series(Unit II) for depths of 217-247 m; and 411-427°C forthe Cretaceous series (Unit III) for depths between 255and 433 m, then, 393-424°C for the deeper part be-tween 436 and 520 m (Figs. 6, 8; Appendix Table 2).

The vertical distribution of TMAX, according to 5°C-wide classes versus depth (Fig. 8), shows, following thetwo values within Neogene Unit II in the 420-424°Cclass, a mode localized in the same 420-424°C class forthe three Cretaceous intervals of depth. Also, an in-crease of the adjacent 425-429°C class is observed forthe two deeper intervals, from depths of 377-519 m.

In the hydrogen index versus TMAX diagram (Fig. 6),all the plots occur in the area largely below the TMAX

900

800

700

600

.£ 500

400

300

200

100

Site 547

Units VIB, VII(Cores B 22 to 30)

®25-4

"350 400 450 500

• Maximum temperature of pyrolysis (°C)

Figure 7. Hydrogen indices versus pyrolysis peak temperatures(TMAX), Site 547.

of 430-435°C and the curve of isoreflectance 0.5, as-signing an immature stage of maturation to all the Site545 samples.

Site 546Considering the limits assigned previously for the sig-

nificance of organic carbon content and production in-dices (Appendix Table 3) only a few TMAX data can beconsidered. They are scattered at the bottom of UnitI and along Unit II with a range of 416-427°C indica-tive of immature material. Higher temperatures from496-550°C found at the bottom of Unit II suggest greatalteration and/or reworked material.

Site 547Within the Cenozoic Units I and II, significant val-

ues appear in Subunit HA. They occur mainly in UnitsIII and IV, ranging from 405 to 424°C (Figs. 7, 8; Ap-pendix Table 4). In Cretaceous Unit V, TMAX variesfrom 414 to 421 °C in the first hundred meters (Cores547A-40 to 547A-51), then from 414 to 427°C for thefollowing hundred meters (Cores 547A-52 to 547A-62),and from 413 to 433°C for the bottom hundred meters(Cores 547A-63 to 547B-6). For Early Jurassic/late Tri-assic Unit VII, two ranges are observed from 436 to444°C and 461 to 479°C, respectively.

725


Maximum temperatures of pyrolysis (°C)

obo

V

o

100

to '

σ>o

10

5 t

o i•

no

to-:

σ>

H5

to' CM

O

oCM

σ>CM

o

in

CM

ao

oCO

σ>00

o

435

o

440

σ>

0

445

o

bID

Λ\

Cores 547A-22-39:

early Eocene

to Late Cretaceous

1011

Figure 8. Pyrolysis assays. Vertical distribution of maximum temperature (TMAX) classes for Sites 545and 547.

When the vertical distribution of TMAX accordingto 5°C-wide classes (Fig. 8 is considered), a progressiveshift of the mode is observed along the Cretaceous UnitV as depths increase. This shift encompasses the 415-419and 425-429°C classes. The same trend extends intoEarly Jurassic/late Triassic Unit VII for samples of the435-444°C range. It does not extend to the overlyingUnits IV and III, that mode being higher (420-424°C)than the adjacent part of Unit V. Such anomalies, espe-cially for Unit IV, suggest reworked material.

In the hydrogen index versus TMAX diagram (Fig. 7),most of the points for Units I to V are clustered in theimmature area. The isoreflectance curve 0.5, at the be-ginning of the oil window, is only reached for samplesof Cores 547A-70 to 547A-73 and 547B-4 and 547B-5 at

the bottom of Unit V for depths of 716-770 m. Only afew samples (Sections 547B-25-4 and 547B-26-4) occurin the oil window and they belong to Unit VII. The oth-er samples of the same unit are more mature: the rangeof TMAX (461-479° C) depends on an advanced stageof maturation (PR > 1 and 1.5). Such a stage, whichwould be anomalously high for this burial depth, shouldbe due to recycled mature organic matter.

Summary

Within Site 547, immature organic material occursthroughout the 700 m of Cenozoic and Cretaceousrocks penetrated. Reworked material is found in the Eo-cene and the Paleocene sections. The oil window shouldbe reached in the Jurassic beyond a depth of 770 m.

726


Petroleum Potential

Total hydrocarbons (SI + S2) (Espitalié et al., 1977)expelled during pyrolysis represent the petroleum poten-tial, expressed as kilograms of hydrocarbons per metricton or rock (kg/t). Five classes were considered as fol-lows: very good, more than 20 kg/t; good, 5.01 to 20.00;medium, 2.01 to 5.00; low, 0.51 to 2.00; and very low,0.50 and less.

Site 544

In Hole 544A, very low to low petroleum potentials(0.08-0.81 kg/t) were found within Neogene Unit I anda low potential (0.83) was found for the Jurassic sampleof Unit IV. In Hole 544B, very low potentials (0.12-0.37kg/t) also characterize Unit I. (Fig. 2, Appendix Table 1)

Site 545

Neogene Units I and II reveal very low petroleum po-tentials (0.14-0.41 kg/t) except at the top and bottomwhere low potentials are present, 0.59-0.89 kg/t, at thetop of Subunit IA and 0.73-1.37 kg/t, at the bottom ofUnit II (Fig. 3, Appendix Table 2). Within Unit III ofCretaceous age, low potentials (0.41-1.44 kg/t) againcharacterize the interval from Cores 28 to 33. Low tomedium contents (1.46-4.71 kg/t) define the intervalfrom Cores 34 to 45 except at the bottom where goodpotentials (6.13-17.12 kg/t) occur. For the interval fromCores 45 to 55, medium to low potentials (0.88-2.61 kg/t)are observed within the early to middle Albian section atthe top whereas very low to low potentials define thevarious sequences of late Aptian (Gargasian) age at thebottom.

In general, very low or low potentials related to car-bonate-rich deposits are found along the whole Neogeneand Cretaceous sections. The only interval with verygood petroleum potential occurs during the middle Al-bian for Cores 41 to 42.

Site 546

Very low potentials (less than 0.20 kg/t) are foundwithin Units I and II except for the bottom of the latterunit where some low contents (0.68-0.93 kg/t) are present(Fig. 4, Appendix Table 3).

Site 547Within Cenozoic Units I, II, and IV, the petroleum

potential is generally very low (0.06-0.57 kg/t). Goodpotentials (6.9-15.8 kg/t) characterize Unit III except atthe bottom where low potentials (0.88-1.73 kg/t) prevail(Fig. 5, Appendix Table 4). For Cretaceous Unit V, aprogressive enrichment is observed ranging from 0.17 atthe top to 1.19 kg/t at the bottom. Rich interlayers oc-cur with content increasing from 1.04 to 1.55 kg/t in theupper part (Core 547B-5). Very low potentials (0.10-0.57 kg/t) occur within Jurassic Unit VII.

Summary

Very low petroleum potential is characteristic of Site547 within the Cenozoic and the Cretaceous sections ex-cept for the very good potential evident in the late Eo-

cene interval and some slight enrichments in the late Al-bian sections just above the Jurassic deposits.

Nature of the Organic Matter

Site 544Immature organic matter is found in all of Unit I of

Holes 544A and 544B as attested to by anomalouslyhigh production indices (PI: 0.37 and higher) (Appen-dix Table 1). This organic matter primarily yields natu-ral hydrocarbons and nonhydrocarbons (peak SI) thatare not yet representative of true petroleum compounds.Moreover, these indigenous components generate largequantities of CO2 when pyrolyzed as shown by the highoxygen indices. Such material will be considered in thisreport as undifferentiated organic matter.

Site 545Except for the immature material within the first

230 m cored of Pleistocene to middle Miocene age, allorganic matters examined from early Miocene and Cre-taceous belong either the marine organic matter thatwas altered during deposition or to an alternation ofwell-preserved and highly altered marine organic matter(Fig. 9, Appendix Table 2). Nonmarine organic matter isonly detected at the base of the late Aptian (Gargasian)sequence.

When the hydrogen index (HI) versus the oxygen in-dex (OI) is plotted (Fig. 9), it is seen that low OI are re-lated to large HI and low HI to large OI. Thus, the datafor Site 545 are distributed in an area extending just be-yond the reference paths of types II and III. This distri-bution is commonly observed when well-preserved or-ganic matter is progressively altered by oxidation (Derooet al., in press), oxygenated organic compounds devel-oping at the expense of the hydrogenated compounds.

Results obtained from kerogen lead us to propose thefollowing hypothesis. The distribution of points observedin the diagram of HI versus OI (Fig. 9) depends on theproportions of pure marine organic matter and oxidizedmatter in the samples. In the present case, the evidencefor oxidation includes burrows within Unit III on bothsides of the contact between Cenomanian and Albiandeposits as shown in Cores 30 to 37 and present abun-dantly in Cores 38 to 55. As no immature organic mat-ter of type III was apparent, except for Sample 545-37-2,42 cm, the oxidized material probably originates fromalteration of marine organic matter.

Returning to Figure 9, from the top to the bottom ofthe hole, undifferentiated organic matter (HI = 106 andless; OI = 478 + ) characterizes Unit I and the upperpart of Unit II. At the bottom of Unit II, during theearly Miocene, some altered marine organic matter oc-curs (HI = 104 to 136; OI = 262 to 330). Most of thesamples in Subunits III-A and III-B (Cenomanian tolate Aptian) correspond to altered marine organic mat-ter (HI = < 200; OI = 200 >) with low organic carboncontent. Well-preserved marine organic matter is foundwithin cores 37 to 44 of Albian age in Subunit IIIB. On-ly two samples (545-50-6, 56 cm and 545-55,CC, 16 cm)correspond to an altered nonmarine type III. The low

727


+1000

900

800

700

600

500

400

300

200

100

Organic carbon

UnitII

III A

III B '

I I I C l

Core

© 20-27-©-28-33® 34-36• 37-40θ 41-44θ 45 46Q 47-55-β•55,CC-56

o 0 -o 0.16-O 0.31-O 0.51-O 1.01-O 151-

0.150.300.501.001.502.00

Oo

2.01-3.003.01-4.00

) 4.01-5.00

ΛΛÖ.OIV_y 10.00

O10.01-15.00

( )>15.00

50 100 150 200 250 300 350 400Oxygen index — *

Figure 9. Hydrogen index versus oxygen index, Site 545. Cores 20 to27, middle to early Miocene; Cores 28 to 33, late to middle Ceno-manian; Cores 34 to 36, early Cenomanian; Cores 37 to 38, lateAlbian (Vraconian); Cores 39 to 40, late Albian; Cores 41 to 44,middle Albian; Cores 45 to 55, middle Albian to late Aptian; and545-55,CC to Core 56, early late Aptian.

HI (22 and 39) of the samples suggest severe oxidationof immature continental organic matter.

Site 546

At Site 546 undifferentiated organic matter with veryhigh OI (754 + ) characterizes the Neogene Unit I (Fig. 10,Appendix Table 3). In Unit II, one sample at interval546-17-3, 22 cm corresponds to altered marine material(HI = 119; OI = 239). For the other samples of Unit II,TMAX (488-550°C) infers an advanced stage of mat-uration incompatible with the low burial depth. Thus,reworking can be proposed for them.

Site 547

Undifferentiated organic matter occurs within the Neo-gene Units I and II (Figs. 11, 12; Appendix Table 4).Marine organic matter, which characterizes the EoceneUnit III, is well-preserved for the organic carbon richlevels of Sections 547A-19-1, 547A-20-1, 547A-20-4, and547A-21-2 (HI = 258-471; OI = 108-126). It is mixed

1000

900

800 •

700

600

500 •

400 •

300 -

200 -

100 -

Organic carbon {%)

/ \/

1I11111

• 1 /

I /«

1I111111

• 18-1,0

^ ^

• 17-4,22

Unit II

I I I

• Core 16-18. 0 -0.15o 0.16-0.30O 0.31-0.50O 0.51-1.00

O 1.01-1.50O 1.51-2.00Q 2.01-3.00

Q 3.01-4.00

ç^) 4.01 -5.00

v_y 10.00

v_y i5.oo

( Vlδ.OO

•17-2,43

• 17-3,22

50 150 200 250Oxygen index

300 350 400

Figure 10. Hydrogen index versus oxygen index, Site 546.

with oxidized marine organic matter in Sections 547A-19-1, 547A-21-4, and 547A-21-6 (HI = 50-227; OI =274-304). Undifferentiated organic matter characterizesUnit IV of early Eocene to Paleocene age, except forSamples 547A-34-3, 84 and 547A-39-1, 29 cm wheresome marine organic matter occurs. For CretaceousUnit V, oxidized organic matter of marine origin pre-dominates over well-preserved material throughout theCenomanian and Albian (Cores 547A-40 to 547A-68).Slight enrichments of well-preserved marine organicmatter is observed downward from Core 547A-67 toCore 547B-5 at the bottom. In Jurassic Unit VI accord-ing to analyses on board, undifferentiated organic mat-ter was found for the sample of Subunit VIA, mixed ornot with marine organic matter in Subunit VIB. Somenonmarine organic matter occurs in Section 547B-22-1(Fig. 12). Well-preserved marine organic matter charac-terizes a thin black shale at interval 547B-20-1, 13 (onboard analysis). In Jurassic/Triassic Unit VII, marineorganic matter is either altered (intervals 547B-25-3, 100;547B-26-2, 102; 547B-27-3, 112; and 547B-30-4, 50) ormixed with a residual organic matter through interval547B-25-3, 93 and mixed with nonmarine organic mat-ter for interval 547B-26-4, 62. Other samples reveal ei-

728


1000

900

800

700

600

500

400

300

200

100

Organic carbon (%) Organic carbon

UnitIIIIVAIVB

Core0 18-21© 23-313 32-39-®- 40-46® 47-62• 63-73

0-0.15o 0.16-0.30O 0.31-0.50O 0.51-1.00O 1.01-1.50O 1.51-2.00

3.01-4.00

10.00

15.00

0-1.55(22)21-2.85

021-6,85

50 100 150 200

Oxygen index

250 300 350 400

Figure 11. Hydrogen index versus oxygen index, Hole 547A. Cores 18to 21, late Eocene; Cores 23 to 31, early Eocene to early Paleo-cene; Cores 32 to 39, early Paleocene and Late Cretaceous; Cores40 to 73, late or middle Cenomanian to late Albian.

ther nonmarine organic matter at 547B-29-1, 112 and547B-30-7, 82 or undetermined organic matter for Sam-ples 547B-27-2, 64 and 547B-29-1, 36.

Summary

Organic matter of continental origin was found inred beds of Early Jurassic to late Triassic age in Hole547B. Marine organic matter indications and one or-ganic carbon rich layer are found higher up in the Juras-sic. Altered organic matter of marine origin predomi-nates throughout the Cretaceous at each site. The altera-tion increases from bottom to top, for example, in Hole547A from late Albian to Cenomanian. For compari-son, the hydrogen index versus oxygen index for Site 370is presented in Figure 13.

Well-preserved marine organic matter mixed with analtered organic matter is present throughout the late Ap-tian and Cenomanian cored at Site 545. Organic carbonrich levels define the series to be of early to middle Albi-an age. Such levels are scattered in the late Albian (Vra-conian) and Cenomanian while the altered organic mat-ter related to burrowing is subordinate or even absent.

800

700

600

g,500

400

300

200

100

UnitV

Core2-5

VIB 0 20-24VII <>25-34

0-0.15o 0.16-0.30O 0.31-0.50O 0.51-1.00O 1.01-1.50O 151-2.00Q ) 2.01-3.00

) 3.01-4.00o( ^ ) 4.01-5.00

r>.01-S=/10.00

O10.01-15.00

15.00

-Φ• 25-3,100

• f26•4,62•(>

253,93HI

30 3 8 2 0 ® 2 2 1 1 5

30-4, 50

26-2, 102-0"

•Φ-27-3, 112

29-1,36 -0-

o4 0

r50 100 150 200 250

Oxygen index300 350 400

Figure 12. Hydrogen index versus oxygen index, Hole 547B. Cores 2to 5, late Albian; Cores 20 to 24, Pliensbachian to Sinemurian;and Cores 25 to 34, Early Jurassic/late Triassic.

Generally, the carbonate series of Cenozoic age re-veals low contents of organic carbon and undeterminedorganic matter. An exception is found in Hole 547A asthe slumps in the late Eocene, Unit III, contain a typicalmarine matter that is organically rich. Such organic mat-ter is similar to the richest levels observed in the middleto early Albian series at Site 545. During the late Eo-cene, these slumps were displaced from the upper partof the continental slope and are composed of Creta-ceous and early Tertiary material. Such an explanationwas invoked by Cornford (1979) and Deroo et al. (1979)at Hole 397 of Leg 47A for similar sediments rich in or-ganic matter. These sediments were cored at the bottomof early Miocene shales which rest directly upon Hau-terivian shales and mudstones. Independently of sedi-mentological evidence, geochemical characteristics ob-served in Site 547 for the Eocene samples of Unit III al-low us to conclude that reworked organic matter wasrecycled from Cretaceous material.

Kerogen Study

Ten samples provided by the Organic GeochemistryPanel were selected from different units of Sites 545 and

729


AIOOO

900

800

700

600

500

400

3 0 0

2 0 0

Organic carbon

Unit

VA

VB

Core

® 20-23• 24-26β 27-29θ 30-32O 33-34

/ II

1,104

0-0.15° 0.16-0.30)λ 0.31-0.50O 0.51-1.00O 1.01-1.50O 1.51-2.00

2.01-3.00QQ 3.01-4.00

(^4.01-5.00

5.01-10.00

O10.01-15.00

>lδ.OO

o

βθ

Θ

32-4,70 27"3,16

Table 1. Elemental composition of kerogens.

28-2,77 31-1,114 ö l f24-3,59

25-2,73j| β'34•=qq •,d 1 r , 30-3,126é^ * r < > ^ 20-2,9434-5,99 34-4.113 4 ? θ ‰ . U 3 9 I 28-3,103

S 2 7 - 1 . 1 2 7 ,50 100 150 200 250

Oxygen index350 400

Figure 13. Hydrogen index versus oxygen index, Site 370. Cores 20 to23, early Cenomanian; Cores 24 to 26, late Albian; Cores 27 to 32,middle to early Albian; and Cores 33 to 34, early Aptian to lateBarremian.

547 and prepared for elemental analysis (C, H, N, O, S,and Fe) of the kerogen concentrations (Table 1). Thisanalysis reveals 22-32 wt.% pyrite equivalent in Site 545and 1-53 wt.% in Site 547. The H/C and O/C ratios inTable 1 are plotted on a Van Krevelen diagram (left sideof Fig. 14) and compared to the Rock-Eval data for thesame samples (right side of Fig. 14), according to thethree reference evolution paths for types I, II, and IIIkerogens of ancient sediments (Tissot et al., 1974).

As indicated on both graphs, an immature stage canbe assigned to all the samples of Sites 545 and 547. InSite 545, a group of three points clusters halfway be-tween path II and path III and the fourth point nearpath III. In Site 547, a single point is localized near andbelow the limit for kerogen: this sample contains de-graded kerogen and is considered residual organic mate-rial (Tissot et al., 1979). Four of the five other pointsare distributed along a trend of increasing O/C ratios(0.16-0.26) while H/C ratios decrease slightly (1.23-1.15). The same trend was observed for pyrolysis of therock samples (right side of Fig. 14). This has been ob-served for two kerogens from Section 511-59-3 in DSDPLeg 75 (Deroo et al., in press) and for kerogens of the

Depth belowComposition (wt.%)

(interval in cm)

Hole 545

34-2, 120-13040-3, 120-13043-4, 135-14555-5, 120-130

Hole 547A

20-1, 55-56a

43-2, 120-13058-4, 120-12573-3, 120-125

Hole 547B

5-6, 113-12325-4, 0-5

(m)

315.20373.70403.85519.20

251.05462.20607.70739.20

769.63937.00

C

36.144.742.343.8

56.427.638.448.2

50.663.4

H

2.84.64.44.5

5.92.73.74.4

5.22.8

N

1.51.81.61.5

2.61.21.82.1

2.11.2

O

15.813.112.113.5

16.59.8

13.012.4

10.913.0

S

13.818.821.318.7

10.628.220.713.6

15.30.8

Fe

10.313.715.114.8

4.724.915.29.1

10.70.6

(wt.%)

19.83.33.43.3

3.35.67.2

10.2

5.318.2

H/C

0.951.231.241.23

1.251.161.151.09

1.230.52

O/C

0.330.220.210.23

0.220.270.250.19

0.160.15

a Composite sample of 547A-20-1, 55-56 cm; 547A-20-4, 55-56 cm, and 547A-21-2, 85-86 cm between251.05 and 262.36 m depth.

lower Toarcian in the Paris basin. Larger O/C ratioswere obtained for weathered samples from outcrops inthe Paris basin, the weathering enriched the organic mat-ter with oxygenated compounds at the expense of thehydrogenated ones. Such a trend was attributed to an al-teration path, quite distinct from the thermal evolutionpath, similar to the one suggested here.

In Site 545, the group of three points clustered half-way between paths II and III are in the same relative po-sition as the Eocene Sample (547A-20, 55 cm). The al-teration trend clearly expressed at Site 547A for bothpyrolysis and kerogen data was not observed at Site 545.

Chloroform Extract Study

The extracts collected from 17 selected samples(Tables 2, 3) represent 0.05-0.20 wt.% of rock in Site545 and 0.06-0.28 wt.% in Site 547. This correspondsto 0.8-1.5% of extract to total organic carbon in Site545 and 1.1-2.3% for Site 547. As is usually found inDSDP sediments, polar compounds of high molecularweight predominate in the extract. Thus, the hydrocar-bons are represented (1) by 15-23% of the total extractfor the Miocene and the Eocene samples, respectively, inSites 545 and 547; (2) 7-18% for the Cretaceous extractsat Site 545 and 11-25% for the extracts of Site 547; and(3) 29% for the Jurassic extract at Site 547.

Four extracts at Site 545 and six at Site 547 were thenselected for capillary gas chromatography (GC) studies(Tables 2, 3). The GC analysis of saturates + unsatu-rates reveals comparable chromatograms for the ana-lyzed samples at Site 545 of Cenomanian, late Albian(Fig. 15B), early to middle Albian, and late Aptian(Fig. 15C) ages. Predominance of C15 and C17 normalalkanes in the C15 to C35 distribution and the occurrenceof sterane/sterene, triterpane/triterpene molecules in then-C27+ range (Fig. 15B) imply a marine origin for theextracts. Predominance of odd numbered molecules inthe n-C23 to Λ-C35 range (Fig. 15A-D) indicates imma-ture material. In the extract of the composite sample(Cores 547A-20 and 547A-21) of late Eocene age, the«-C14 to n-QYl mode is so prominent that the n-C2j+alkanes are barely detected (Fig. 15A). The chromato-grams of Site 547 for Cenomanian extracts look similarthose of Site 545 (Fig. 15). For Vraconian and late Al-

730


• * — i • Direction of increasing evolution———— Domain of existence of kerogensT-TT-TTT Evolution paths of kerogen types

Domain of existence of vitrinites

» 34-2,120-130

m

A20-1,55/21-2,86A58-4.120-125

A43-2,120-130

B5-6.113-12

A73-3,120-125

0.2 0.3

O/C (atomic ratio)

8 0 0

6 0 0

4 0 0

2 0 0

.*-«

43-4, 135-145

40-3, 120-130% #55-5,120-130

34-2, 120-130

ffl

0.5 - 100 200 300 4 0 0 5 0 0

8 0 0

600

4 0 0

200-

0 -

/ If

1/ /

1 / π

A20-1,55/21-2,86•

A73-3, 120-125

/ B25-4, 0-5 ^ - ^• m

,113-123

A58-4, 120-125

"X^ A 4 3 " 2 '^ w _ ^ 120-130

100 200 300 400 500

Oxygen index ^

Figure 14. H/C versus O/C diagram of kerogens compared with HI versus OI diagram for rock pyrolysis at Sites 545 and 547.

Table 2. Composition of chloroform extracts, Hole 545.

Samples(interval in cm)

26-1, 120-1303

34-2, 120-13021

37-2, 135-14540-3, 120-130*43-4, 135-145a

46-4, 120-13052-5, 120-13055-5, 120-1303

Depth belowseafloor

(m)

237.20315.20343.85373.70403.85432.20490.70519.20

HCC13

extract(wt., mg)

2.47.18.26.06.32.69.15.9

Extractto rock

(%)

0.0060.0130.0150.0200.011

0.0080.0050.012

Extract toorg. carbon

( * )

1.41.11.51.20.8

O.«0.91.3

Thin layer chromatography fractionation

High-molecular

-weightcompounds

(%)

8593848993828492

AromaticsOft)

0122

< l45

< l

Saturates +unsaturates

W

156

1497

14118

1 Gas chromatography analyses.

bian age extracts, the n-alkane distribution begins witha slight n-C16 mode within the Λ-C1 4 to n-C2\ range(Fig. 15D). This is followed by a flat distribution fromAZ-C22 t° Λ"C32 Similar distributions were observed forimmature organic matter of type I in Green River Shales(Tissot et al., 1978). A slight predominance of phytaneupon pristane occurs (Fig. 15D). The composite distri-

bution for the n-alkanes suggests a mixed contributionof marine type I and type II organic matters. Sterane/sterene and triterpane/triterpene molecules are againdetected. For the older sample analyzed of Jurassic(? Liassic) age, the distribution differs from that of theCretaceous by the disappearance of the odd predomi-nance, suggesting a more advanced stage of maturation.

731


Table 3. Composition of chloroform extracts, Holes 547A and 547B.

Samples(interval in cm)

Hole 547A

20-1, 55-56ab

43-2, 120-130s

49-2, 120-13058-4, 120-125a

61-3, 140-15073-3, 12O-125a

Hole 547B

2-4, 120-1305-6, 113-123a

25-4, 0-5a

Depth belowseafloor

(m)

251.05462.20519.20607.70634.90739.20

739.70769.63937.00

HCC13

extract(wt., mg)

1.13.46.43.0

13.88.9

12.810.82.3

Extractto rock

0.0280.0060.0110.0120.0120.023

0.0160.0180.010

Extract toorg. carbon

1.11.11.51.61.91.7

1.21.42.3

Thin layer chromatography fractionation

High-molecular-weight Saturates +

compounds Aromatics unsaturates(%) (Vo) (%)

,777581858584

8589

71

6, 172519151516

1511

9 20

a Gas chromatography analyses.b Composite sample of 547A-20-1, 55-56 cm; 547A-20-4, 55-56 cm, and 547A-21-2, 85-86 cm between 252.05 and

262.36 m depth.

DISTRIBUTION OF ORGANIC MATTER DURINGTHE EARLY AND MID-CRETACEOUS IN SITES

545 AND 547 COMPARED WITH SITE 370

Drilling was conducted along the Moroccan platformon DSDP Legs 14, 41, 50, and most recently during Leg79. Thus, the Mazagan Escarpment edge at Site 545, ora high block structure just below the escarpment on theslope at Sites 544 and 547, can be compared with the ba-sin sediments found at Sites 370 and 416 off the AgadirCanyon.

The vertical distribution of organic matter betweenSites 370, 545, and 547 during the early Aptian to earlyCenomanian period should be compared. Stratigraphicages for Site 370 have been revised in the North Atlanticarea (Graciansky et al., 1982). For the other sites, agesare based on shipboard data for planktonic foramini-fers. Limits for the Albian series are clearly establishedfor the three sites. Vraconian subseries were distinguishedfrom late Albian subseries at Sites 370 and 545, whilegravity driven redeposition disturbs the sediments of thesame age at Site 547. Early to middle Albian subseriesoverlie the early Aptian at Site 370. They are absent atSite 547. At Site 545 they overlie a repeated series of lateAptian (upper late Gargasian and lower late Gargasian)age. It is clear from the HI and OI diagrams (Figs. 9-13)that marine organic matter largely predominates overnonmarine organic mater in the interval from the earlyCenomanian to early late Aptian for Sites 547 and 545.

Characterization of Organic Matter

Nonmarine organic matter, absent at Site 547, is bare-ly represented at Site 545; for example in 545-37-2, 42cm in the Vraconian series it is well preserved; whereas itis altered in the core catcher of Core 545-55 and at 545-50-6, 56 cm in the late Aptian slices (Fig. 9). Nonmarineorganic matter, altered or well-preserved, is more largelydistributed at Site 370 (Fig. 13). Altered material charac-terizes the organic matter of several samples (370-31-3,47 cm; 370-30-3, 126 cm; and 370-30-1, 139 cm) or con-tributes to its composition (370-32-4, 70 cm; 370-31-1,114 cm; 370-30-3, 115 cm; 370-29-1, 104 cm; 370-28-4,

116 cm; and 370-28-2, 77 cm) during the early to middleAlbian time. Well-preserved nonmarine organic matteroccurs in the same interval (370-28-3, 109 cm and 370-27-1, 127 cm). It is also found within the Vraconian/lateAlbian intervals (370-26-3, 22 cm and 370-26-3, 93 cm;370-25-2, 73 cm; and 370-24-3, 59 cm) and the early Ce-nomanian interval (370-20-2, 94 cm). Some contribu-tion of nonmarine organic matter also occurs in the ear-ly Aptian/late Barremian series; well preserved for Sam-ple 370-34-2, 63 cm and 370-34-2, 116 cm and for Samples370-34-4, 113 cm and 370-34-5, 99 cm altered, presum-ably reworked, into calcareous sands.

The best preserved organic matter of marine originwas found in early to middle Albian at Sites 370 and 545and also in late Albian to Vraconian in Site 545. Alteredmaterial of the same origin characterizes the early Ce-nomanian for the three sites (Fig. 16). Alteration in-creases from site 545 to Site 547. Altered marine materi-al also characterizes the Vraconian to late Albian periodfor Site 370 and Site 547. In the latter, several trends ofincreasing alteration are observed, with an increase inthe OI corresponding to a decrease in both the HI andthe organic carbon content. Intraformational conglom-erates (pebbly claystone) at or close to the bottom of atrend as found at intervals 547A-73-3, 52 cm, 547A-71-1,52 cm, and 547A-61-3, 52 cm indicate a gravitational re-sedimentation. Since the bottom of a trend correspondswith pebbly claystones at 547A-73-3, 52 cm, 547A-71-1,52 cm, and 547A-61-3, 52 cm, the beginning of a gravi-tational resedimentation cycle is suggested.

Altered marine material also occurs in the late Apti-an slices of Site 545. Several trends, beginning with deep-ly altered at the base of a slice and evolving toward pro-gressively less altered marine organic matter at the topwere observed from 545-53-3, 98 cm to 545-52-5, 120 cm,and 545-51-1, 46 cm; from 545-50-6, 56 cm to 545-50-2,57 cm to 545-49-6, 23 cm, and 545-49-3, 120 cm; from545-49-2, 20 cm to 545-48-5, 38 cm, and 545-48-1,52 cm. Deeply altered organic matter at the base repre-sents terrestrial input that rhythmically disturbed thenatural sedimentation of marine organic matter. Alteredmarine material also characterizes most of the early Ap-tian at Site 370.

732


B LiIA A i

jiÀ

20 -

15 -

10 -

2 0 -

1 5 -

1 0 -

2 0 -

1 5 -

1 0 -

2 0 -

1 5 -

1 0 -

Pristane

Phytane

15 20 25 30 35 40

Carbon atom number Carbon atom number

Figure 15. Chloroform extracts. Gas chromatography of saturated + unsaturated hydrocarbons. (A) Sam-ple 547A-20-4, 55-56 to 547A-21-2, 85-86 cm; late Eocene. (B) Sample 545-40-3, 120-130 cm; late Al-bian. (C) Sample 545-55-5, 120-130 cm; late Aptian (Gargasian). (D) Sample 547A-73-3, 120-125 cm;Vraconian + late Albian.

Vertical Distribution of Organic Matter andEnvironments of Deposition

As shown before, variations of HI and OI indices re-flect the conditions of preservation for immature ma-rine organic matter when deposited. Thus, anoxic envi-ronments of deposition can be deduced given the well-preserved marine organic matter detected at Sites 370,

545, and 547 (Fig. 16). HI and OI indices were studiedfor the entire Cretaceous interval.

During the late Aptian at Site 545, the mixing of al-tered marine organic matter with nonmarine altered or-ganic matter was similar to the distribution observedwithin the late Barremian/early Aptian at Site 370. AtSite 370 during the early to middle Albian, well-pre-served organic matter of marine origin developed at the

733


Site 370 Site 545 Site 547

earlyCenomanian

300

- 200

100

1

1 \

Cores 20 to 23

100 200 300Oxygen index

400 100 200 300 400

300

200

100

100 200 300 400

Vraconian+

late Albian

100 200 300 400

400

300

200

100

Cores 547A-63to547A-73547B-2 to 547B-5

<*>.

>

100 200 300 400 100 200 300 400

500

400

middle + early

Albiana

500

400

100 200 300 400

Increasing trend of altered material

100 200 300 400

late Aptian

200

100

100 200 300 400 500 600 700

Sample 32-4, 83 cm toSample 34-2, (bottom]

To late Aptian at Site 545

Figure 16. Vertical distribution and comparison of HI versus OI for Aptian to Cenomanian ages in Sites 370, 545 and 547.

upper and lower bounds of the interval in Cores 27 to 28and Cores 30 to 32, respectively. Reducing environmentscan be inferred even though nonmarine altered organicmatter was present throughout the series. More land-ward at Site 545, altered marine organic matter charac-terizes the early Albian. Reducing environments andwell-preserved marine organic matter appear later andextend from the middle to the late Albian. No continen-tal organic material occurs.

Within the late Albian and the Vraconian at Site 370,altered marine organic matter prevails, interlayered withnonmarine organic matter. Reducing environments ofdeposition disappear later during the Vraconian at Site545. Here, altered marine organic matter is found in re-deposited material of late Albian and Vraconian as inSite 547. Altered marine organic matter continues to befound within the early Cenomanian at the three sites,

but alteration is less developed at Site 545 than at Sites547 and 370 (Fig. 16). Table 4 sums up the distributionof organic matter and environments of deposition forthe three sites within the Cretaceous interval.

CONCLUSIONS

Within the Eocene slumps of Unit III in Hole 547A,carbonate-rich and organic carbon rich contents corre-late. Organic carbon rich material also occurs in Site545 for the middle Albian part (Cores 41 to 43) of Sub-unit IIIA. A very low stage of maturation characterizesthe organic matter throughout the middle Miocene toPleistocene sections. The main zone of oil genesis (oilwindow) just reaches into the Jurassic section of Site547 beyond 700 m depth. In that site, the anomalies ofmaturation observed for the samples of both Eocene-Paleocene Units III and IV and Jurassic Unit VII are

734


Table 4. Vertical distribution of organic matter at Holes 370, 545, 547A, and 547B within Cretaceous sections.

early Cenomanian

Vraconian

late Albian

middleto

earlyAlbian

late Aptian

early Aptianto late

Barremian

Hole 370

Cores370-20-23

Marine organic matter, deeplyaltered

OC 0.2/1.0%

Cores370-24-25

Core370-26

Altered marine organic matterand unaltered nonmarineorganic matter

OC = 0.3/1.3%

Cores370-27-370-29

Cores370-30-370-32

Well-preserved marine andnonmarine altered organicmatter

Reduced environment

OC = 0.2/5.3%

Cores370-33-370-34

Altered marine organic matterand nonmarine organicmatter (calcareous sand)

OC = 0.6/2.3%

Hole 545

Cores545-34-545-36

Marine organic matter, al-tered

OC = 1.1/2.4%

Cores545-37-545-38

Altered marine organic matterand nonmarine organicmatter at top

OC = 0.3/1.3%

Cores545-39-545-40

Cores545-41-545-43

Well-preserved marine organicmatter

Reduced environment

OC = 1.2/4.5%

Cores545.44-545.46

Altered marine organic matter

OC = 0.4/1.3%

Cores545-47-545-55

Altered marine organic matterand nonmarine alteredinputs in repeated se-quences + undeterminedorganic matter at bottom

OC = 4/1.1%

Holes 547A, 547B

Cores547A47-547-A62

Marine organic matter,largely altered

OC = 0.5/1.0%

Cores547A-63 to 547B-6

Redeposited alteredorganic matter ofmarine origin inrepeated sequences

OC = 0.5/1/5 and 2.0a%

Note: OC = organic carbona On board analyses.

related to reworked and recycled material. Good petro-leum potentials are found in the previously defined or-ganic carbon rich intervals and also at the bottom ofCretaceous Unit V for Site 547.

Whereas various types of organic matter are presentin the Jurassic samples (Units VI and VII) of Hole 547B,marine organic matter, variably altered, predominatesthroughout the Cretaceous series. The best preserved or-ganic matter corresponds to the organic carbon rich lay-ers and intervals defined above; if no redeposition oc-curred then the presence of organic matter implies re-ducing environments of deposition.

Along a transect from Sites 545 and 547 to 370, oxy-genated marine organic matter prevailed during Aptiantime. The distribution in Site 370 and 545 is disturbedby inputs of nonmarine altered organic matter. Such al-tered material continued at Site 370 up to the Vraconianin spite of the presence of reducing environments of ear-ly to middle Albian age. However, reducing environ-ments appear later at Site 545 during the middle Albianand extend to the late Albian. During the Vraconianand the Cenomanian periods, variably altered marineorganic matter characterizes all the sites, including thesedimentary sequences that lie directly upon the LateJurassic at Site 547.

Thus, away from the Mazagan escarpment, off theAgadir Canyon in the abyssal plain (Site 370), detritalinputs extend beyond the Albian and the reducing envi-ronments appear earlier in the Albian than at the bot-tom edge of the escarpment (Site 545). After the reduc-ing period, marine organic matter is variably oxidizedthroughout the late Albian to Cenomanian periods.

ACKNOWLEDGMENTSThe authors are indebted to Dr. R. Cunningham and to Dr. Leslie

B. Magoon III for reviewing the present paper.

REFERENCES

Cornford, C , 1979. Organic deposition at a continental rise: organicgeochemical interpretation and synthesis at DSDP Site 397, East-ern North Atlantic. In von Rad, U, Ryan, W. B. F. et al., Init.Repts. DSDP, 47, Pt. 1: Washington (U.S. Govt. Printing Office),503-510.

Deroo, G., Herbin, J. P., Roucaché, J., and Tissot, B., 1979. Organicgeochemistry of some organic-rich shales from DSDP Site 397,Leg 47 A, Eastern North Atlantic. In von Rad, U., Ryan, W. B. F.et al., Init. Repts. DSDP, 47, Pt. 1: Washington (U.S. Govt. Print-ing Office), 523-529.

Deroo, G., Herbin, J. P., and Roucaché, J., 1983. Organic geochemis-try of Cretaceous sediments from Site 511, Leg 71, Western SouthAtlantic. In Ludwig, W. J., Krasheninnikov, V. A., et al., Init.Repts. DSDP, 71: Washington (U.S. Govt. Printing Office).

Deroo, G., Herbin, J. P., and Hue, A. Y., in press. Organic geochem-istry of Cretaceous black shales from DSDP Site 530, Leg 75,Eastern South Atlantic. In Hay, W. W., Sibuet, J. C , et al., Init.Repts. DSDP, 75: Washington (U.S. Govt. Printing Office).

Espitalié, J., and Deroo, G., in press. The development of Rock-Evalanalysis. In Ikan, R., and Aizenshtat, Z. (Eds.), Organic Thermo-geochemistry.

Espitalié, J., Laporte, J. L., Madec, M., Marquis, R, Leplat, P., Paulet,J., and Boutefeu, A., 1977. Méthode rapide de caractérisation desroches-mères, de leur potentiel pétrolier et de leur degré d'évolu-tion. Rev. Inst. Fr. Pétrole, 'il .l‰Al.

Espitalié, J., Marquis, F., and Barsony, I., in press. Geochemical log-ging. In Voorhees, K. J. (Ed.), Analytical Pyrolysis. 5th Int. Meet-ing on Analytical Pyrolysis, Vail, Colorado, Sept. 1982.

Graciansky, P. C. de, Brosse, E., Deroo, G., Herbin, J. P., Montadert,L., Müller, C , Schaaf, A., and Sigal, J., 1982. Les formationsd'áge Crétacé de 1'Atlantique Nord et leur matière organique: pa-léogéographie et milieux de depot. Rev. Inst. Fr. Pét., 37:275-336.

Hue, A. Y., Durand, B., and Monin, J. C , 1978. Humic compoundsand kerogen in cores from Black Sea sediments, Leg 42-B, Holes

735


379-A, B and 380-A. In Ross, D. A., Neprochnov, Y. P. et al., Init.Repts. DSDP, 42, Pt. 2: Washington (U.S. Govt. Printing Office),737-748.

Tissot, B., Durand, B., Espitalié, J., and Combaz, A., 1974. Influ-ence of the nature and diagenesis of organic matter in the forma-tion of petroleum. Am. Assoc. Pet. Geol. Bull., 58:499-506.

Tissot, B., Deroo, G., and Hood, A., 1978. Geochemical study of theUinta basin: formation of petroleum from the Green River Forma-tion. Geochem. Cosmochim. Acta, 42:1469-1485.

Tissot, B., Deroo, G., and Herbin, J. P., 1979. Organic matter in Cre-taceous sediments of the North Atlantic: contribution to sedimen-tology and paleogeography. In Talwani, M., Hay, W., Ryan, W. B.F. (Eds.), Deep drilling results in the Atlantic Ocean: continentalmargins andpaleoenvironment, Am. Geophys. Un., Maurice Ew-ing Ser., 3:362-374.

Date of Initial Receipt: November 8, 1982Date of Acceptance: August 4, 1983

APPENDIXSample Information, Carbon, and Pyrolysis Assay Data

Table 1. Site 544.

Core, section(interval in cm)

Hole 544A

1-1 (75-76)1-3 (75-76)1-5 (75-76)2-1 (100-102)2-3 (100-102)2-5 (100-102)3-1 (65-68)3-3 (8-9)3-6 (65-66)4-1 (80-81)5-1 (70-71)5-3 (30-31)6-1 (22-23)6-3 (140-141)7-1 (100-101)7-3 (100-101)8-1 (80-81)8-3 (80-81)9-1 (34-35)9-3 (34-35)10-1 (130-131)10-3 (130-131)10-5 (131-131)20-2 (135-145)

Hole 544B

1-1 (80-81)1-3 (17-18)2-2 (44-45)2-3 (37-38)3-1 (98-99)4-1 (59-60)5-2 (40-41)6-3 (75-76)7-2 (77-78)8-2 (20-21)9-2 (72-73)10-2 (56-57)11-1 (40-41)12-1 (41-47)

Depthbelow

seafloor(m)

0.753.756.758.00

11.0014.0017.1519.5824.6526.8036.2038.8045.2249.4055.5057.5064.8067.8073.8476.8484.3087.3090.30

159.85

0.803.174.345.777.78

11.7917.5023.7526.6729.1033.1235.7636.8037.81

Geologicalformation

orUnit

Unit I

Unit IVA

I Tnit Tunit l

Mineralcarbon(wt.%)

6.47.59.47.66.57.87.78.17.19.27.99.58.68.77.98.4

12.09.59.68.59.18.48.01.8

7.17.85.96.98.38.07.78.57.98.79.08.98.99.0

Organiccarbon(wt.%)

0.200.160.120.180.150.180.170.210.190.140.140.110.120.090.180.140.110.120.130.150.090.110.100.13

0.170.280.180.140.130.180.140.140.100.100.090.110.130.19

Hydrogenindex

(mg hydro-carbons/g

OC)

25569

22517

34719459955814937325067

121736792

100786470

554

10068788692726471608067731742

Oxygenindex

(mg Cθ2/gOC)

11301413147510001167961

1000852

107911641057132714421789

878929

10271025

946933

135512641330

331

1318668917

13001400

8561129117915801460157813001031710

Petroleumpotential

(mg hydro-carbons/g

rock)

0.810.310.420.110.600.450.210.320.250.090.220.170.090.080.240.260.100.110.170.210.070.100.080.84

0.370.270.200.230.230.240.190.200.110.150.150.170.120.18

Pyrolysistempera-

ture(°C)

399430502355450455392448404373457456383

403453421380415402383335363517

512406443441396436388417360400410461339364

Productionindex(PI)

0.370.670.360.800.130.230.550.370.580.870.410.560.751.000.500.350.200.300.310.300.000.300.120.14

0.560.310.300.500.500.460.560.500.500.500.640.560.580.56

736


Table 2. Hole 545.


1-1 (90-91)2-2 (90-91)3-1 (90-91)3-3 (90-91)3-5 (90-91)4-1 (90-91)8-3 (60-61)10-2 (70-71)11-3 (45-46)12-4 (50-51)13-2 (50-51)14-2 (50-51)19-4 (34-35)20-1 (58-59)21-1 (50-51)22-1 (50-51)22-1 (60-61)23-1 (5-6)24-1 (40-41)24-4 (5-6)25-3 (20-21)26-1 (93-94)26-1 (120-130)27-1 (94-95)28-1 (63-64)29-1 (23-24)29-1 (135-145)30-1 (3-4)31-1 (9-10)32-1 (38-39)33-1 (20-21)34-1 (84-85)34-1 (117-119)34-2(50-51)34-2 (120-130)35-1 (20-21)36-1 (95-%)37-2 (42-43)37-2 (135-145)38-2 (100-101)38-3 (100-101)39-2 (99-100)39-4 (99-100)40-2 (35-36)40-3 (120-130)40-5 (57-58)41-1 (41-42)41-4 (30-31)42-2 (20-22)43-4 (135-145)43-6, 94-9544-1 (0-1)45-4 (94-95)46-2 (62-63)46-4 (62-63)46-4 (120-130)47-2 (95-96)47-6 (71-72)48-1 (52-53)48-5 (38-39)49-2 (23-24)49-3 (120-130)49-6 (20-21)50-2 (57-58)50-6 (56-57)51-1 (46-47)52-5 (25-26)52-5 (120-130)53-3 (98-100)54-4 (130-132)55-5 (120-130)55.CC (16-17)56-4 (59-60)56-6 (58-59)

Depth Geologicalbelow formation

seafloor or(m) Unit

0.9010.9018.9021.90 Unit IA24.2128.4069.1086.7097.45

108.50115.00 Unit IB124.50174.34179.58189.00198.50198.60212.05217.40 „ . π

221.55 U m t "229.70236.93237.20246.44255.63264.73265.85274.03283.59293.38302.70313.34313.67314.50315.20322.20332.45342.92 Unit IIIA343.85353.00354.50362.49365.49371.05373.70376.07379.41383.80390.20403.85460.44407.50422.44428.62431.62432.20438.45444.21446.02451.88456.73459.20 . . . π T R

462.70 U m t I I I B

466.57472.56474.46489.75490.704%.98508.30519.20519.66526.59 .529.58 U m t I I I C

Mineralcarbon(wt.%)

7.25.94.43.17.07.27.18.19.39.08.88.67.79.59.59.38.98.77.77.78.55.36.74.42.42.32.92.71.83.23.42.34.14.03.94.04.33.14.18.46.43.66.26.44.95.54.65.13.34.95.07.93.96.05.35.45.97.17.05.37.16.68.25.16.06.16.66.55.46.87.55.66.55.7

Organiccarbon(wt.%)

0.280.470.460.340.400.410.360.190.120.130.150.120.190.190.120.120.130.140.560.140.170.610.450.770.730.550.881.050.721.211.032.361.201.181.571.221.101.270.941.881.011.221.941.331.391.583.762.384.461.561.650.391.300.721.300.800.990.630.670.700.480.510.430.530.570.370.380.400.600.400.891.120.240.09

Hydrogenindex

(mg hydro-carbons/g

OC)

75106336293

10238

10575694775688983676271

1045047

13678

1365851

14272

1611541152291091302041151157596

345143138294227219273387331363299202

7715211718414113412215114398

1511238739

105403

603253

22122

113378

Oxygenindex

(mg Cθ2/gOC)

1064596565603555524478826

1125931867

1383747668

10671125908

1057318

1086794330473262329453314356432250239127220223208216209184272119239239148175195149839571

163122364134205151283163187182293229259244260212432360488338688258

81554

3155

Petroleumpotential

(mg hydro-carbons/g

rock)

0.410.840.630.390.590.650.410.340.180.170.140.170.240.260.180.160.170.210.730.150.171.100.481.370.580.411.440.991.482.251.465.861.541.773.531.641.461.141.136.951.621.986.133.303.484.74

15.238.36

17.125.083.620.362.190.882.611.311.530.851.121.180.550.840.600.530.300.491.730.300.250.312.160.320.330.52

Pyrolysistempera-

ture( ° Q

401410392437414417403402437397404440395412402402403425421407404418413420417411424420422425411423423426424423422418417424424423422425423424423422420423423416425427425420421424424418416420419393395408421410447391426377414366

Productionindex(PI)

0.500.400.400.470.380.360.500.410.500.500.500.500.460.350.440.500.560.550.210.570.560.250.270.240.280.320.130.230.220.170.180.080.150.130.090.150.140.170.200.070.110.150.070.080.130.090.040.060.060.080.080.170.100.050.080.140.130.100.100.150.150.080.120.130.270.210.120.200.250.330.090.220.190.35

737


Table 3. Hole 546.


1-1 (100-101)2-1 (25-26)2-3 (25-26)3-1 (79-80)3-3 (79-80)4-1 (125-126)4-3 (125-126)6-1 (145-146)6-3 (30-32)6-4 (34-36)7-1 (80-83)7-3 (80-83)7-5 (80-83)8-2 (20-22)8-4 (20-22)8-6 (20-22)9-1 (20-22)9-3 (20-22)9-5 (20-22)10-1 (20-22)10-3 (20-22)10-5 (20-22)11-1 (20-22)11-3(20-22)12-2 (102-103)12-4 (102-103)13-1 (100-101)13-3 (100-101)14-1 (100-101)14-3 (100-101)15-1 (47-48)17-1 (76-77)17-2 (43-44)17-2 (52-53)17-3 (22-23)17-4 (22-23)18-1 (0-10)

Depth Geologicalbelow formation

seafloor or(m) Unit

1.002.255.25

12.2915.2922.2525.2541.4543.3044.8450.3053.3056.3060.706 3 7 0 Unit T66.70 U m t l

68.7071.7074.7078.2081.2084.2087.7090.7099.52

102.52107.50110.50117.00120.00125.97146.26146.43146.52 Unit II147.72149.22154.00

Mineralcarbon(wt.%)

5.17.25.49.55.66.76.46.84.96.76.55.86.47.27.67.87.77.97.77.67.67.68.18.68.48.58.69.27.78.77.39.11.84.06.91.61.7

Organiccarbon(wt.<Pb)

0.320.260.280.170.180.190.190.200.230.190.180.160.170.170.150.120.150.130.130.150.140.110.110.120.110.130.120.090.090.090.250.070.200.100.690.410.27

Hydrogenindex

(mg hydro-carbons/g

OC)

755457

11883959985656878695976536753626940500

10030456283

14424421121615742024011376

337

Oxygenindex

(mg CO2 /gOC)

809754800

1018939

1116974760878979900988853847980

1125947

11381038940

1000218

13911167132710151117138914781422716

12002354702394152

Petroleumpotential

(mg hydro-carbons/g

rock)

0.390.240.240.310.220.290.270.280.240.210.230.200.170.230.170.160.190.170.160.130.160.010.200.130.100.120.190.160.260.240.680.130.880.270.820.350.93

Pyrolysistempera-

ture( ° Q

417439453433439407414444445452447437432445381387457352383380403327368372329396436541528517416514544488427496550

Productionindex(PI)

0.390.420.330.370.320.390.380.390.370.400.410.450.440.450.560.500.610.560.440.580.560.000.450.580.500.330.470.190.150.210.210.170.050.120.050.120.02

738


Table 4. Site 547.


Hole 547

1-2 (84-85)16-2 (30-31)

Hole 547A

1-4 (89-90)2-2 (86-87)3-1 (32-33)4-1 (32-33)5-3 (27-28)6-1 (50-51)7-1 (52-53)8-4 (34-35)8-5 (34-35)9-1 (71-72)10-1 (71-72)11-1 (90-91)11-3(90-91)12-1 (60-61)12-3 (60-61)13-1 (53-54)14-2 (80-81)14-4 (80-81)15-1 (35-36)17-2 (10-11)19-1 (41-43)19-1 (49-51)20-1 (55-56)20-4 (55-56)21-2 (85-86)21-4 (85-86)21-6 (85-86)22-2 (85-86)23-3 (79-80)24-1 (122-123)25-4 (16-17)26-1 (44-45)27-1 (103-104)28-2 (87-88)30-1 (69-71)32-1 (85-86)32-4 (50-51)33-1 (63-64)33-3 (63-64)33-4 (140-150)33-5 (139-140)34-1 (64-65)34-3 (84-85)34-5 (83-84)34-7 (15-16)35-2 (81-83)36-2 (58-59)36-3 (7-8)37-2 (66-67)37-2 (120-130)37-4 (66-67)38-1 (56-57)38-3 (122-123)39-1 (20-21)40-1 (20-21)40-1 (140-150)41-1 (20-21)42-2 (140-141)43-1 (21-22)43-2 (120-130)44-1 (77-78)44-3 (35-36)44-5 (26-27)45-1 (16-17)45-3 (16-17)46-1 (62-63)46-2 (120-125)46-3 (62-63)47-1(52-53)47-3 (52-53)48-1 (52-53)49-1 (52-53)49-2 (120-130)50-1 (82-83)50-3 (82-83)51-1 (52-53)51-3 (52-53)52-1 (52-53)52-2 (145-150)52-3 (52-53)53-1 (52-53)54-2 (70-72)55-1 (23-24)55-5 (120-130)56-1 (55-56)57-1 (52-53)57-3 (52-53)57-5 (52-53)58-1 (52-53)58-3 (52-53)58-4 (120-125)

Depthbelow

seafloor(m)

2.34214.30

56.3981.8689.3298.82

111.27118.00127.52141.34142.84146.71156.21165.90168.90175.10178.10184.53195.80198.80203.35223.60241.41241.49251.05255.55262.35265.35268.35271.85282.79289.72302.66307.94318.03328.87346.19365.35369.50374.63377.63379.90381.39384.14387.34390.33392.65395.31399.58400.57404.66405.20407.66412.56416.22421.70431.20432.40440.70452.90459.71462.20469.77472.35475.26478.66481.86488.62490.70491.62498.02501.02507.52517.02519.20526.82529.82536.02539.02545.52547.95548.52555.02566.20573.73580.70583.55593.02596.02599.02602.52605.52607.70

Geologicalformation

orUnit

I Tnit Tunii i

Unit I

I Init II Δunii i iA

Unit IIB

Unit HI

Unit TVΔuiiii. i VΛ

Unit IVB

Unit V

Mineralcarbon(wt.%)

6.46.0

6.67.1

7.2

9.2

8.4

9.1

9.2

8.4

8.69.4

9.2

7.8

8.8

8.89.4

9.2

8.8

8.0

7.65.0

4.84.0

8.3

7.6

7.92.3

7.9

8.57.7

7.89.4

5.8

4.96.7

7.83.1

2.5

7.8

7.7

7.87.3

8.8

6.6

5.2

5.67.9

8.68.6

7.8

8.28.18.2

8.6

3.6

2.43.4

1.93.7

3.4

2.63.0

4.4

5.3

3.3

5.13.4

3.23.7

3.4

3.7

3.4

2.63.2

2.5

3.13.1

4.33.7

4.2

4.0

4.3

3.9

1.9

3.9

3.8

3.94.4

4.1

4.2

2.53.2

Organiccarbon(wt.%)

0.410.19

0.250.230.300.100.100.220.100.170.270.100.500.270.110.160.110.110.120.400.310.232.480.482.633.112.280.620.660.400.180.180.250.420.440.250.190.140.240.320.150.120.140.130.570.210.330.100.240.190.120.110.280.110.120.620.530.600.470.500.920.470.430.600.400.410.440.810.660.500.490.510.830.600.680.670.660.740.690.700.660.700.790.920.700.630.801.020.850.740.740.870.97

Hydrogenindex

(mg hydro-carbons/g

OC)

6163

44

48

6050

50

32

30

53

37

40

92104

55

56

0

236142

133

116157

258

50433471

435

106227

250

205167

120

129

123152

68

286146

109

80

208107

69107

86100

30

2947

25

28279

36

5871

75145

68

7696

47

74

42

7071

73

62

9560

63

75

93

8071

81

8884

80

93

9183

95104

111

86

120

134

112

103108

99

88

Oxygenindex

(mg Cθ2/gOC)

771

1005

832

930

733

20002130

723

18801118670

1630256

633

1082606

809

1000992

420

594

913

108275117

111

126

274304

525

14281061264

614

511

696

679936

842

478

960

11251093869346

1029621

1360629758

11671210646

1355958

300336

405

379

358220

494

398

327

443

483414

274

294414

518

469284

462387

337

368

368325

430298

389

308

233274

452

226

215252

281

396277

252

Petroleumpotential

(mg hydro-carbons/g

rock)

0.430.20

0.220.190.290.090.100.140.060.160.150.080.570.390.120.160.060.330.280.720.490.486.910.32

12.3215.8110.720.881.731.200.570.440.400.670.690.460.170.500.500.420.170.250.210.150.770.270.460.050.130.140.060.340.290.090.150.590.580.950.470.501.040.310.470.330.400.400.470.620.700.400.450.500.940.620.600.690.730.760.650.790.710.710.861.070.890.591.081.521.070.880.951.010.98

Pyrolysistempera-

ture(°C)

393

425

394

437

388

416317

461322

391

419344

405384434

477

500521

410

409412

424

398422

419

421

419

419All

449

462

409420

421

423441

450428

424

446

489447

418420424

424

416

370427

320

503413

379

358410411

420404

415419

412

408413

409410

408

421

420413412

414

421

417417415

416

418

418

420414

416

420

425425

416424

426

421

420

421424

426

Productionindex(PI)

0.430.40

0.500.440.390.500.500.500.500.440.360.500.200.290.500.441.000.220.390.260.270.250.070.250.080.070.070.250.130.170.360.320.250.200.220.170.250.200.300.170.310.000.300.430.210.350.280.500.500.360.500.090.250.620.570.260.310.090.330.240.150.290.330.250.300.270.330.190.100.250.320.240.180.230.200.220.210.180.160.180.160.190.130.100.120.090.110.100.110.140.160.150.13

739


Table 4. (Continued).


Hole 547A (Cont.)

58-5 (52-53)59-1(52-53)59-3 (52-53)59-5 (52-53)60-1 (52-53)60-3 (52-53)60-5 (52-53)61-1 (52-53)61-3 (52-53)61-3 (140-150)62-1 (52-53)62-3 (52-53)63-1 (52-53)63-3 (52-53)64-1 (52-53)64-2 (120-125)64-3 (52-53)66-1 (34-35)67-2 (34-35)67-2 (120-125)68-1 (68-70)69-1 (52-55)69-3 (52-53)70-1 (52-53)70-2(106-116)70-3 (52-53)71-1 (52-53)72-1 (52-53)72-3 (52-53)73-1 (52-53)73-3 (52-53)73-3 (120-125)

Hole S47B

2-1 (52-53)2-3 (52-53)2-4 (120-130)2-5 (52-53)4-3 (70-71)5-1(52-53)5-3 (52-53)5-5 (52-53)5-6(113-123)22-1 (15-16)25-3 (100-101)25-3 (93-94)25-4 (0-5)26-2 (102-103)26-4 (62-64)27-2 (64-65)27-2(112-113)27-3(112-113)28-3 (83-84)29-1 (36-37)29-1 (112-113)30-3 (82-83)30-4 (50-55)31-3 (92-93)32.CC (23-24)34-1 (145-150)

Depthbelow

seafloor(m)

606.52612.02615.02618.02622.02625.02628.02631.02634.02634.90640.52643.52650.02653.02659.52661.70662.52678.34689.34690.20697.68707.02710.02716.52718.56719.52721.02726.02729.02735.52738.52739.20

734.52737.52739.70740.52756.70763.02766.02769.02769.63915.15936.43936.50937.00944.02946.62952.64953.12954.62963.33968.86969.62981.32982.60990.42

1000.001010.95

Geologicalformation

or

Unit

Unit V

Unit VIB

T Tnit VTTunit vii

Mineralcarbon(wt.%)

4.9

3.84.4

4.9

2.52.64.1

4.3

3.9

3.83.83.4

4.9

5.3

4.3

4.54.6

4.1

6.9

5.55.5

7.35.8

8.1

7.65.67.1

7.4

8.6

5.24.64.2

6.33.41.7

3.4

5.34.3

4.1

4.3

4.1

1.9

2.93.9

2.5

2.64.3

3.61.7

3.63.2

6.6

4.0

3.3

2.63.2

2.32.4

Organiccarbon(wt.%)

0.960.660.670.940.800.730.850.600.690.620.750.550.960.900.940.740.880.810.681.170.710.691.390.680.731.110.720.580.450.881.101.28

1.121.341.131.341.451.131.101.491.160.730.400.180.410.180.360.400.150.230.140.210.310.290.190.150.110.07

Hydrogenindex

(mg hydro-carbons/g

O C )

142

103100

119

8388

75

88

80

5687

78106

129117

103

8941

119

19877

129171

150

145195190

138

127130

188

171

147

157

128

148224

180

185213

181

60

128255

24111

136

45187

74

136

105

58

59168

67

64414

Oxygenindex

(mg Cθ2/gOC)

232298

349

225251

255234

390

291

440

336347

219

233206

284

216

278207

197

286241

157 •

245

295

229242

246284

259

228

225

178153262

187

135

209

252

146234

185

48205

95

311122

470393

248

3791114

177

176253

460482

886

Petroleumpotential

(mg hydro-carbons/g

rock)

1.550.780.781.230.780.760.770.640.640.450.750.51l . U

1.281.210.850.880.400.882.400.620.992.361.111.102.321.510.900.641.252.212.34

1.772.231.642.093.392.162.183.412.270.490.570.520.130.250.550.230.340.210.230.320.210.200.320.140.100.29

Pyrolysistempera-

ture( ° Q

426422421

427

419

419421

419417

414420

418

428427

427

423423

413427

431420

429433

429428432

431424

426424

430

430

428

429

426428

431

431

430427

431

475

461473436467444

478454

479

478397

478467

476457

410

444

Productionindex(PI)

0.120.130.140.090.150.160.170.170.140.220.140.160.080.090.090.110.110.170.080.030.110.100.060.080.040.060.090.110.110.090.060.06

0.070.060.120.050.040.060.070.070.070.100.110.120.230.210.110.230.180.200.180.310.150.150.000.290.300.00

740


Table 5. Hole 370.


19-1(68-73)20-1 (65-70)20-2 (82-85)20-2 (94-96)20-3 (43-45)20-3 (110-112)21-2(110-112)21-2 (119-121)22-2 (26-28)22-3 (39-41)22-4 (76-78)23-2 (52-56)23-2 (123-125)23-3 (19-21)23-4 (84-86)23-4(109-111)23-4 (139-141)24-2 (47-50)24-3 (27-28)24-3 (28-30)24-3 (59-61)24-3 (113-115)24-5 (11-13)24-5 (62-64)25-1 (139-141)25-2 (73-75)25-2(114-116)25-2 (135-137)25-2 (145-147)26-2 (30-32)26-2 (54-56)26-3 (22-25)26-3 (93-95)26-4(9-11)26-4(112-114)27-1 (124-126)27-1 (127-129)27-3(6-8)27-3 (10-12)27-3 (23-25)27-3 (101-103)28-2 (19-23)28 = 2(70-72)28-2 (77-79)28-3 (103-105)28-4(116-118)28-4 (142-144)29-1 (104-106)30-1(139-141)30-2 (31-36)30-2 (61-63)30-2 (64-66)30-2 (66-68)30-2 (68-70)30-3 (102-104)30-3 (115-117)30-3 (126-128)31-1 (46-50)31-1 (109-111)31-1 (114-116)31-2 (24-26)31-3 (26-28)31-3 (47-49)31-3 (126-168)31-4 (146-148)32-3 (38-40)32-3 (82-86)32-3 (79-81)32-4 (19-21)32-4 (70-72)32-4 (99-100)32-4 (132-134)33,CC33.CC34-2 (63-65)34-2 (81-83)34-2(116-118)34-3 (102-104)34-4(113-114)34-5 (99-100)35-5 (22-24)35-4 (38-40)35-4 (82-84)35-5 (10-12)35-5 (49-42)35-5 (52-54)

Depthbelow

seafloor(m)

654.70673.70675.30675.44676.43677.10685.10685.19693.76695.39697.26703.50704.23704.69706.84707.09707.39713.00714.27714.28714.59715.13717.11717.62722.89723.73724.14724.35724.45731.80732.04733.20733.93734.59735.62750.24750.27752.06752.10752.23753.01769.70770.20770.27772.03773.66773.92788.04807.39807.81808.11808.14808.16808.18810.02810.15810.26825.50826.09826.14826.74828.26828.47829.26830.%837.88838.30838.76839.19839.70839.99840.3853.50854.00874.63874.81875.16876.52878.13879.49885.22886.88887.32888.10888.40888.52

Geologicalformation Mineral

or carbonUnit (wt.%)

Unit IV 5.32.03.7

0.42.0

2.82.20.90.81.6

2.52.30.7

1.0

1.92.85.62.7

7.1

3.90.8

2.2.8.8.5

.2

.3

.7

1.7

1.22.4

2.03.0

.4

.7

.5

.5

.62.40.4

0.60.7

Unit V 0.40.60.4

0.60.0

0.50.8

0.00.80.7

1.4

0.10.7

0.80.7

1.50.62.8

0.60.8

0.01.62.8

2.20.00.6

0.62.4

3.4

1.33.4

5.23.7

3.81.89.69.2

1.63.63.42.83.00.4

Organiccarbon(wt.%)

0.480.620.580.820.970.660.620.770.720.650.400.430.660.580.370.310.210.600.280.280.960.331.040.310.520.840.640.260.320.481.280.520.630.411.101.580.240.772.052.753.440.271.090.490.680.481.200.740.240.173.993.082.071.802.341.370.280.181.220.521.382.030.194.525.296.164.104.300.241.681.770.870.870.920.560.990.781.191.272.340.421.080.261.651.613.12

Hydrogenindex

(mg hydro-carbons/g

OC)

123698949

66

636548468346

61454859

311

6744

1

55

467734

455274

5741

51

95715462

115207

42

143246324

288

223186

11551

101178

9934

224

349317

205278194127

42

197

18586

320

23022

362457

503

431459120134

198180

59137

90149107

12411

579

1311795

196208

Oxygenindex

(mg Cθ2/gOC)

450347297

196281

408395279419335

593302397

326419

461

1019245489

689175

403258623310

155278

269606373

198194

192

490232

111175

87

70101

34

12268

80179

10069

26142

12924

59

50985662

150167

115102130

53

13219

6367

56

35221

54

130148224167

161233

153151

4923

245212

569110

14956

Petroleumpotential

(mg hydro-carbons/g

rock)

0.610.480.530.440.690.460.450.400.370.580.190.270.330.280.240.100.020.420.150.020.560.200.840.150.380.470.540.190.200.311.280.380.350.301.433.400.211.175.179.04

10.030.622.110.630.380.562.210.770.230.36

14.069.864.325.084.621.850.160.372.340.514.494.740.13

16.4324.1930.9917.7919.970.362.293.571.610.551.280.541.570.881.510.190.180.391.480.191.653.236.56

Pyrolysistempera-

ture(°C)

426422423426414

418423426426417

426424411

426438414

420

404419

425

425

440401

430425421

432417

433422428417

421

423

422432

419409432

422417

428413

422

438

441

426428

426434427

423

424414420430

426418416

425428

420427427424430427

422416427424

425412437

433

428422

426

Productionindex(PI)

0.05

0.040.050.040.040.030.040.040.01

0.040.000.030.010.02

0.030.020.030.050.040.050.150.030.060.050.070.060.06

0.020.050.170.130.110.070.130.130.11

0.080.070.030.070.070.040.140.060.150.010.020.010.020.060.240.040.030.130.020.020.670.010.000.000.010.010.210.020.020.030.050.020.070.070.050.020.230.290.150.050.770.050.020.01

741

30. organic geochemistry of cenozoic and mesozoic ... · cenozoic and mesozoic sediments ranging in...

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