18. ORGANOFACIES VARIATIONS IN SEDIMENTS FROM THE ...€¦ · 1986). This well mixed and oxygen-rich water mass affects the accu-mulation of labile organic material, so that only

Mountain, G.S., Miller, K.G., Blum, P., Poag, C.W., and Twichell, D.C. (Eds.), 1996Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 150

18. ORGANOFACIES VARIATIONS IN SEDIMENTS FROM THE CONTINENTAL SLOPE AND RISEOF THE NEW JERSEY CONTINENTAL MARGIN (SITES 903 AND 905)1

Jan Hendrik van der Smissen2 and Jürgen Rullkötter2

ABSTRACT

This study describes molecular organic geochemical investigations of 14 samples from Site 903 off New Jersey, as well asbulk analysis of a great number of sediments from Sites 903 and 905. Detailed lipid analysis of the solvent-extractable organicmatter exhibits a complex assemblage of marine, terrigenous, and bacterial compounds. rc-Alkanes and n-alcohols are the mostabundant compounds in extracts of sediments from Site 903, followed by steroidal alcohols in considerably smaller concentra-tions that decrease with depth. Analysis of long-chain unsaturated ketones for reconstruction of paleo-sea surface temperatureresults in an average water temperature estimate of 25°C since the middle Miocene. The results indicate continuous supply ofterrigenous organic material to the region with occasional conditions of better marine organic matter preservation, particularlyin Oligocene to middle Miocene times. Some variations in organic matter composition may be caused by sea-level changes. Awarm current analogous to the present Gulf Stream appears to have existed off New Jersey at least since the Oligocene.

INTRODUCTION

Sediments deposited along ancient continental margins representa significant portion of the geological record and comprise a sensitiveand long-term record of environmental change. During regressionphases of the ocean caused by climatic change, major parts of thecontinental shelf area fell dry (Mountain and Miller, 1993/94). At thattime, rivers transported terrestrial material to the outer continentalshelf and slope. Cyclic variations in the supply of terrigenous organicmatter over geological times should be documented by the composi-tion of inherited fossil organic matter, so that these sediments offer apossibility for organic geochemical investigations of environmentalchange.

Accumulation and preservation of marine organic matter are con-trolled by a number of different factors, for example, the primary bio-logical productivity in the surface water, the supply of terrigenous or-ganic material from the continent (which in turn is a function of con-tinental climate), the amount of oxygen in the water column, andmicrobial and chemical diagenetic alteration in the sediments. Thecontinental rise off New Jersey, at least in modern times, is influ-enced by the Western Boundary Undercurrent (WBU), a strongsouthwest-flowing bottom current composed primarily of North At-lantic Deep Water with an admixture of Antarctic Bottom Water(Amos et al., 1971; Heezen et al., 1966; McCave and Tucholke,1986). This well mixed and oxygen-rich water mass affects the accu-mulation of labile organic material, so that only a small part of theoriginal marine organic matter and terrigenous supply will be pre-served, but this effect may have varied with time. Thus, an investiga-tion of the quantity and composition of organic matter in deep-seasediments on the New Jersey continental margin may still provide in-formation on changes in paleoenvironment, such as sea-level changesand associated terrigenous supply by river transport.

Molecular organic geochemical studies of sediments are basedmostly upon the presence of chemical fossils (or biological markers),

'Mountain, G.S., Miller, K.G., Blum, P., Poag, C.W., and Twichell, D.C. (Eds.),1996. Proc. ODP, Sci. Results, 150: College Station, TX (Ocean Drilling Program).

institute of Chemistry and Biology of the Marine Environment (ICBM), Carl vonOssietzky Universitat Oldenburg, P.O. Box 2503, D-26111 Oldenburg, Federal Repub-lic of Germany.

a group of compounds that, from their occurrence in the organic mat-ter fraction of a sediment, provides a link to a specific type of organ-ism or a larger family of organisms (Eglinton and Calvin, 1967;Philp, 1985; Poynter and Eglinton, 1990). Examples of such com-pounds are 4α,23,24-trimethyl-5α(H)-cholest-22-en-3ß-ol (dinoster-ol) or 24-ethylcholest-5-en-3ß-ol as indicators of dinoflagellates orhigher land plants, respectively (e.g., Volkman, 1986). Thus, in amore specific way than bulk organic geochemical parameters, bio-logical marker assemblages reflect paleoenvironmental changes oforganic matter deposition.

The coastal plain, shelf, and slope off New Jersey have long beenrecognized as a source of information on sea-level history. They pro-vide a record of transgressive and regressive sequences that can becorrelated with other proxies of sea-level changes (Owens and Gohn,1985; Olsson et al.,1987; Olsson and Wise, 1987). For a selected setof samples from Sites 903 and 905, this study reports results of an in-vestigation of bulk characteristics (i.e., total organic carbon, carbon-ate, and sulfur contents) and of the composition of extractable lipidscovering a range of compound classes (hydrocarbons, sterols, fattyacids, and alkenones), using gas chromatography (GC) and combinedgas chromatography-mass spectrometry (GC/MS), as a first attemptto relate the results to climatic changes and sea-level variations.

LITHOLOGICAL DESCRIPTIONAND ANALYTICAL METHODS

Lithology

Ocean Drilling Program (ODP) Site 903 (Fig. 1) is located at38°56.298'N and 72°49.032'W at the distal end of the continentalshelf (upper continental slope; water depth 446 meters [m]; Ship-board Scientific Party, 1994a). Drilling at Site 903 recovered 1149.7m of sediment spanning a record from the middle Eocene to the Pleis-tocene (the last 45 Ma). The sediments consist of Pleistocene toPliocene silty clays and sand (lithologic Units I and II); upper andmiddle Miocene alternations of silty clays and glauconitic sands(Unit III); middle Miocene diatomaceous silty clays to clayey silts in-cluding slumps and debris flow deposits (Unit IV); lower to middleMiocene glauconitic, diatomaceous, organic-matter-rich silty clay-stones (Unit V); lowermost Miocene to upper Oligocene silty clay-stones (Unit VI); and upper Eocene clayey nannofossil chalks (UnitVII).

329

J.H. VAN DER SMISSEN, J. RULLKOTTER

41°N

77°W 76° 75° 74° 73

Figure 1. Drilling locations on the New Jersey continental margin during Leg 150.

Drilling was also performed at Site 905 (38°36.828'N, 72°17.024'W; water depth 2698 m; Shipboard Scientific Party, 1994b),which is located at the continental rise off New Jersey (Fig. 1). Fourlithostratigraphic units were recognized at Site 905 down to a termi-nal depth of 910.6 mbsf. They comprise lower Pleistocene conglom-eratic clay almost entirely representing mass-transport deposits ofterrigenous origin (Unit I), lower Pleistocene to upper Miocene ho-mogeneous silty clay with low terrigenous contribution (Unit II), sev-eral complex upper to middle Miocene units of conglomeratic clay(Unit III), and upper middle Miocene silty clay with little terrigenousinfluence and abundant diatoms (Unit IV).

Analytical Methods

A total of 122 samples (received frozen) from ODP Sites 903 and905 were analyzed for bulk geochemical characteristics. Aliquots ofthe freeze-dried and ground sediments were used to determine totalcarbon (TC), total organic carbon (TOC), and total sulfur (TS) con-tents with a LECO SC-444 instrument. Before TOC determination,the samples were treated with hydrochloric acid to remove carbon-ates. Carbonate contents were calculated by difference and expressedas percent calcium carbonate. The release of hydrocarbons and car-bon dioxide during temperature-programmed pyrolysis was deter-

mined as hydrogen indices (HI: mg HC/g TOC) and oxygen indices(OI: mg CO2/g TOC), respectively (Espitalié et al, 1977).

From the total number of samples, 14 were selected for detailedstudies of the molecular organic matter composition. The ground sed-iments were ultrasonically extracted three times (15 min each) withdichlormethane (containing 1% methanol). After each step, the sol-vent was decanted. All three extracts were combined. Known quanti-ties of internal standards (squalane, erucic acid, 5α(H)-androstan-17-one) were added to allow later quantitative measurement of lipidabundances. Before separation into molecular group fractions, the n-hexane soluble compounds (after precipitation of asphaltenes) weredivided into two aliquots. The larger portion (80%) was separated bymedium-pressure liquid chromatography (MPLC) (Radke et al.,1980) into compound classes of different polarities, that is, aliphatichydrocarbons, aromatic hydrocarbons, and polar hetero(NSO)-com-ponents. Carboxylic acids were separated from the polar compoundsby using a column filled with silica gel 60 impregnated with 0.5 gKOH dissolved in 10 mL wo-propanol. The nonacidic compoundswere eluted from the column with dichlormethane. Alcohols and ke-tones were separated from the acid-free NSO fraction by flash chro-matography (Still et al., 1978) under N2 pressure using dichlo-romethane and dichloromethane/10% methanol as eluents. Wherenecessary, the extract fractions were derivatized with diazomethane

330

ORGANOFACIES VARIATIONS IN CONTINENTAL SLOPE SEDIMENTS

and N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) beforeanalysis.

GC analysis was conducted on a Hewlett-Packard 5890 series IIinstrument equipped with a temperature-programmable injector sys-tem (Gerstel KAS 3), a fused silica capillary column (30 m × 0.25mm i.d., film thickness 0.25µm) and a flame ionization detector(FID). The temperature of the GC oven was programmed from 60°C(1 min isothermal) to 300°C (50 min isothermal) at 3°C/min. The in-jector temperature was programmed from 60°C (5 s hold time) to300°C (60 s hold time) at 8°C/s. GC/MS measurements were per-formed with the same type of GC system, under the conditions de-scribed above, coupled to a Finnigan SSQ 710 B mass spectrometeroperated at 70 eV with a cyclic scan time of 1 scan/s. Compoundswere identified by comparing their relative gas chromatographic re-tention times and mass spectra with those reported in the literature.Quantification was performed relative to the amount of internal stan-dards in the gas chromatograms.

RESULTS AND DISCUSSION

Bulk Parameters

The downhole variations in bulk composition of the sedimentsfrom Sites 903 and 905 in terms of organic carbon, sulfur, and car-bonate contents are shown in Figures 2 and 3. For better correlations,curve fits were calculated using a five-point weighted running aver-age smoothing function. Data of organic carbon, CaCO3, and elemen-tal analysis of sediments at Site 903 and 905 are listed in Tables 1 and2. Rock-Eval pyrolysis, and extract yields of selected samples fromSite 903 are summarized in Table 3. Eocene sediments at Site 903 arerich in carbonate (35% to nearly 60%), but lean in organic carbon(around 0.5%). Carbonate concentrations decrease significantly inthe Oligocene and are very low throughout most of the Miocene andPliocene, with slightly higher values on average in the continentalrise sediments compared to those from the upper slope. Carbonateconcentrations of about 10% are typical of the Pleistocene sections atboth sites.

The decrease in carbonate content in the Oligocene at Site 903 isaccompanied by a strong increase in organic carbon concentration.Similarly high TOC values of more than 2% were measured for thelower Miocene and part of the middle Miocene sections at Site 903whereas in the shallower part of the middle Miocene, the upper Mio-cene, and the Pliocene sections at both sites TOC values vary be-tween 1% and 1.5% for most of the samples analyzed. The variationsof organic matter concentrations are probably not simply related todilution with biogenic carbonate, because there is no general correla-tion between carbonate and organic carbon contents over a largerdepth range. Even from Eocene to Oligocene, where there is an obvi-ous negative correlation between the two carbon parameters, changesin organic matter quality (e.g., hydrogen indices; Table 3) are evi-dence against simple dilution. The Pleistocene sediments are charac-terized by low organic carbon contents (<0.5%), with a few excep-tions at the continental rise, which probably represent slump clasts ofmore organic-matter-rich (Miocene?) sediment originally depositedat a shallower site under conditions of better preservation of organicmatter.

Microbial sulfate reduction leading to relatively high total sulfurcontents (l%-2%) in the sediment was most effective in those sec-tions of the sedimentary column that also have preserved higheramounts of organic carbon. This indicates that the deposition of labileorganic matter (probably marine to a large extent) was higher in Oli-gocene to Pliocene times than it was in the Eocene and the Pleis-tocene. Of the organic material preserved in the sediments, the ma-rine organic matter portion appears highest during the lower and mid-dle Miocene, according to the hydrogen index values from Rock-Eval pyrolysis (Table 3), but there is probably still a significant ad-mixture of terrigenous organic matter because absolute HI values are

still below 300 mg HC/g TOC. High concentrations of methane inthese sediments suggest that pronounced methanogenesis has metab-olized a significant part of the deposited labile marine organic matter.Eocene as well as upper Miocene and younger sediments, accordingto their HI and OI values, mostly contain terrigenous and oxidized re-sidual organic matter; oxidation may partly be the result of strong mi-crobial reworking near the sediment/water interface. The Rock-Evaldata fit well into the HI profile reported by the shipboard party (Ship-board Scientific Party, 1994a, 1994b).

The amount of extractable organic material varies between 10 and20 mg/g TOC; thus, they are in typical range of deep-sea sedimentscontaining immature organic matter. The total extracts are dominatedby the NSO fractions, followed by asphaltenes, and the aliphatic andaromatic hydrocarbons (Fig. 4). All core samples selected for molec-ular analysis contain a significant proportion of extractable elementalsulfur (10%-30% of total extract).

Molecular InvestigationsAliphatic Hydrocarbons

The most important biogenic constituents in the aliphatic hydro-carbon fractions are straight-chain n-alkanes, of which the C29 or C31

members are predominant. The n-alkane distribution patterns aresimilar for most of the samples studied. Carbon preference index val-ues (CPI31) (Bray and Evans, 1961) vary between 2.8 and 5.8, sug-gesting that there was a significant supply of terrigenous lipids fromepicuticular waxes of higher land plants to the sediments (Eglintonand Calvin, 1967; Kolattukudy, 1976). A typical example of a Pleis-tocene sediment with only a minor proportion of marine organic mat-ter is shown in Figure 5 A. Steroid and hopanoid hydrocarbons, irre-spective of progress in diagenesis, are minor compounds when com-pared with n-alkanes in these samples. In contrast to this, middle andlower Miocene sediments in addition to n-alkanes contain complexmixtures of saturated and unsaturated steroid and hopanoid hydrocar-bons (Fig. 5B). Absolute concentrations and n-alkane carbon numberdistributions of all 14 sediments used for molecular analysis areshown in Figure 6. The n-alkane distribution of Sample 150-903A-13H-4, 87-92 cm (119.37 mbsf, Pleistocene) indicates contaminationas evident from the abundance of lower-molecular-weight homologs,the low CPI value, and the high absolute concentrations. Apart fromthat, n-alkane concentrations (normalized to total organic carbon) ap-pear to increase with depth down to the upper part of the middle Mio-cene section (about 600 mbsf) and then to decrease toward the bottomof the hole. This is consistent with the better conditions for organicmatter preservation in middle Miocene to Oligocene sedimentswhich may also have affected the accumulation rate of terrigenous n-alkanes.

Major biomarker compounds identified in the sediments enrichedin marine organic matter (e.g., Fig. 5B) are sterenes in the carbonnumber range from C27 to C29 (mainly Δ4 and Δ5 isomers), which arelikely to be mainly of marine planktonic origin although a contribu-tion from terrestrial higher plants cannot be fully excluded (Volk-man, 1986). In agreement with the suggested source of the n-al-kanes, however, are the degraded triterpen°ids of the des-A-ole-anene and -ursene types, which are specific for land-derivedangiosperm organic matter. Among the hopanoid compounds of bac-terial origin, hop-17(21)-enes are the major constituents whereas17ß(H),21ß(H)-hopanes are present in smaller concentrations. Inmore deeply buried samples, fern-8-ene and fern-9(ll)-ene, themore stable isomers of this group of compounds, are present in smallamounts. All these compounds are typical of bacterial origin (e.g.,Brassell, 1985; McEvoy et al., 1981; Volkman et al., 1986).

n-Alcohols and Sterols

A typical partial reconstructed ion chromatogram from GC/MSanalysis of the alcohol fractions (analyzed as trimethylsilyl ethers) of

331

TOC

200

400

w

£ 600

αoQ

800

1000

1200

Sulfur (%)

2 3 20 40 60 Unit

Figure 2. Depth profiles of total organic carbon, sulfur, and carbonate contents in sediments from the upper continental slope off New Jersey, Site 903. Curves were calculated by a five-point weighted runningaverage smoothing function.

TOC (%) Sulfur (%) CaCO3 (%

|

αα>Q

100

200

300

400

500

600

0

Φ

seen

eist

<

α.Φ

1

upperPliocene

lowerPliocene

ΦcΦ

8IsΦQ.C LD

mid

dle

Mio

cene

T.D. 910 mbsf

{I Φ

-

1

I

Φ ^

Φ */

Φ / *

Φ C

Φ (Φ W

T Φ/ Φ

Φ * fΦ (

* \

Φ Φ

Φ / * ^

2 0 1

Φ

-

-

IΦ i

yT

Φ r

A*\ Λ1 Φ

* (

* V

i

Φ J

1 . .

2 3I • • •4

Φ

-

>Φ +

Φ *Φ

Φ ΦΦ

Φ

|

0 10I

. Φ

Φ rΦjJl Φ

ΦJT Φ

Φ|

VAt**\* 1 Φ

1 *- Φ * J

Φ /Φ 1

_ J Φ

Φ > ^

Φ ^ / ^ ^ *^ r Φ

< ^

>> Φ

1

20

1

ΦΦ

I

30 Unit

-

_

-

1

II

III

700

Figure 3. Depth profiles of total organic carbon, sulfur, and carbonate contents in sediments from the continental rise off New Jersey, Site 905. Curves were calculated by a five-point weighted running averagesmoothing function.


Table 1. Lithology, organic carbon content, and elemental analysis data for core samples from Site 903.

Core, section,interval (cm)

Depth(mbsf) Lithology

TOC(wt%)

CaCO3

(wt%)Sulfur(wt%)

150-903 A-1H-4, 94-1002H-3, 80-863H-3, 80-864H-5,76-825H-5, 81-866H-2, 62-687H-2, 65-718H-3, 93-999H-4, 5-1110H-3, 90-9511H-4, 6-1212H-3, 83-9013H-4, 87-9216H-2, 52-5716H-2, 100-10317H-1,20-2317H-2, 68-7418H-1,20-2518H-2, 89-9119H-2, 90-9620H-1,90-9621X-1, 90-9622X-3, 60-6623X-1, 137-14324X-2, 24-2925X-6, 12-1826X-3, 83-8827X-5, 120-12628X-4, 99-10529X-3, 90-9530X-3, 57-6331X-5, 20-2532X-1, 16-2033X-5, 60-6534X-5, 80-8635X-6, 10-1636X-3, 17-2037X-2,17-1938X-6, 17-2039X-1, 127-13340X-2, 85-9141X-4, 52-5842X-2, 51-5643X-2, 53-5944X-4, 45-5145X-3, 60-6646X-4, 101-10647X-4, 30-3648X-2, 60-6649X-4, 33-3850X-5, 44-5051X-2,40-4652X-3, 54-6053X-4, 90-9654X-4,40-4655X-4, 40-4656X-4, 90-9357X-1,56-5958X-2, 12-1559X-1, 99-10360X-2, 110-11561X-2, 116-12262X-6, 96-10263X-3, 21-2764X-3, 118-12465X-1, 31-3767X-4, 91-9768X-2, 91-9569X-4, 76-8270X-4, 70-7671X-1, 26-3172X-5, 20-2573X-1,23-2874X-4, 120-12675X-6, 26-3276X-5, 20-26

150-903C-5R-2, 57-637R-4, 10-149R-2, 13-1910R-1, 110-11612R-1, 89-9413R-1, 95-10114R-4, 27-3315R-4, 24-3016R-3, 94-9817R-3, 120-126

5.413.322.835.244.849.659.170.480.589.499.5

108.3119.4145.0146.0149.2151.2154.2156.4162.4165.4170.4176.4183.7198.8209.0214.8227.8235.8243.9253.3265.5269.0284.8294.0305.5316.6317.9334.4337.7348.3360.7367.4376.9389.5397.9409.0418.5425.4437.8449.1454.1465.4477.0486.2495.8506.0510.7521.5530.5541.8551.5566.9571.0581.7587.4611.7618.4630.8640.4644.9660.6664.3679.5691.2699.3

507.6519.9588.1593.2689.5699.1712.6721.9730.9741.0

Homogeneous clayey siltClayey silt with fine sand layersHeavily bioturbated clayey siltHeavily bioturbated clayey silt and silty clayGray clayey silt and silty clay, heavily bioturbatedSilty clay with sand- and black sulfide-filled burrowsHeavily bioturbated silty clay and very fine sandSilty clay and clayey siltSilty clay and clayey siltHeavily bioturbated silty clay and clayey siltSilty clay and clayey silt with pyritic very fine to fine sandSilty clay and clayey silt; pyritic, very dark sand fills burrowsSilty clay and clayey siltSlightly bioturbated silty clay and clayey siltSilty clay and clayey siltSilty clay and clayey silt with iron sulfide-rich black fine sand fills burrowsSilty clay and clayey siltSlightly bioturbated silty clay and clayey siltSlightly bioturbated silty clay and clayey siltSlightly to moderately bioturbated silty clay and clayey siltSlightly bioturbated silty clay and clayey siltBioturbated silty clayModerately bioturbated clayey siltModerately bioturbated clayey siltHomogeneous silty clay and diatomaceous claySilty clay and sandy siltHomogeneous green diatomaceous silty claySilty clay and sandy silty clayVariably bioturbated clayey siltSlightly to moderately bioturbated sandy silty clay and clayey siltHeavily bioturbated silty clay and sand/silt/claySlightly to moderately bioturbated sand-silt-claySilty clay and sandy silty claySlightly bioturbated silty clay and sandy silty claySilty clay and clayey siltSilty sandSlightly bioturbated silty clayGreenish gray silty clayHomogenous silty claySilty clay, homogeneous sandy clay and fine to medium sandGlauconitic sand and silty sandGlauconitic sand, sandy silt and clayey siltSandy silt and homogeneous clayey siltModerately bioturbated sandy siltSilty sand and silty clayHeavily bioturbated silty clayModerately to heavily bioturbated clayey silt, silt and sandy siltSilty clay, glauconitic sandy silt and claySilty clay and glauconitic sandy siltSilty clay and glauconitic sandy siltHeavily bioturbated glauconitic silty sandHeavily bioturbated glauconitic silty sand and clayModerately bioturbated silty clay and sandy claySlightly bioturbated silty clay and sandy silty clayWeakly bioturbated silty clay and sandy clayey siltSilty clay and sandy, clayey siltModerately bioturbated sandy, silty claySandy, silty claySandy silty clay and silty clayHomogeneous silty clayHomogeneous silty clayHomogeneous silty clay/claystoneHomogeneous silty clay/claystoneHomogeneous silty clay/claystoneGlauconitic sand/silt/clay, glauconitic silty clay, silty clay and clayModerately bioturbated clay and silty clayModerately to heavily bioturbated silty clay and sandy siltSand, clayey silt and silty clayClaySlightly bioturbated clay and silty clayModerately bioturbated silty clayModerately bioturbated silty clayHomogeneous silty claySlightly bioturbated silty clay and clayey siltSlightly to moderately bioturbated silty claySlightly to moderately bioturbated silty clay

Glauconitic silty fine sand and glauconitic sandy siltSandy silt, glauconitic sandy silt and silty claySlightly bioturbated clayClay and glauconitic sandy claySlightly to moderately bioturbated claystoneClayey silt to silty clay and glauconitic sandy siltClayey silt and silty clayModerately to heavily bioturbated silty claySilty clay and interbedded sandy silt and silty clayClaystone

0.440.320.350.300.330.330.310.350.400.400.330.430.650.350.300.260.370.280.290.280.270.290.280.350.910.390.450.420.480.450.330.210.270.450.530.760.330.350.530.840.760.531.210.810.971.190.841.141.160.810.911.231.042.310.712.581.191.631.381.140.850.570.940.531.970.360.681.570.401.080.942.231.971.501.641.77

1.681.250.540.611.631.161.331.440.390.68

9.78.55.55.54.65.45.73.73.32.1

13.910.513.94.23.84.34.23.64.73.75.36.37.69.6

18.09.4

12.313.811.810.63.03.89.5

15.921.39.55.45.04.97.20.20.81.01.72.52.11.83.60.34.52.10.16.10.36.00.20.92.70.30.90.32.54.32.16.89.92.77.27.56.76.11.08.2

14.39.43.8

3.64.63.62.75.23.84.44.04.2

0.360.150.140.130.140.090.110.120.170.150.250.110.160.270.190.410.130.100.140.140.110.100.150.140.370.530.340.530.340.250.160.080.170.160.100.650.160.410.310.541.851.201.601.600.881.480.640.481.360.280.941.830.362.220.412.140.861.080.900.600.170.121.460.392.000.841.471.900.241.611.761.691.570.691.951.70

0.702.420.250.191.891.315.130.520.270.18

334


Table 1 (continued).



TOC(wt%)

CaCO3

(wt%)Sulfur(wt%)

18R-3, 75-7819R-2, 86-8920R-5, 100-10321R-1,37-4222R-3, 62-6823R-2, 19-2524R-1, 13-1925R-1,40-4627R-1, 125-13028R-2, 130-13629R-1, 60-6631R-2,44-4832R-2, 22-2533R-1,26-3234R-1,50-5535R-4, 13-1936R-2, 97-10237R-2, 97-1023 8R-1,60-6539R-3, 60-6340R-2, 100-10641R-4, 33-3944R-2, 60-6446R-1, 99-10547R-2, 62-6648R-4, 21-2449R-4, 144-14751R-4, 35-4152R-3.6-1153R-3, 127-13154R-3, 4-1055R-3, 91-9856R-2, 89-9257R-2, 140-14358R-6, 36-4159R-2, 62-6960R-2, 30-34

749.4758.5771.6775.9788.8796.6804.2814.2834.3845.5853.0873.6883.1891.3901.2913.9922.4932.2939.6952.2960.7972.3998.6

1007.21027.61033.31039.71057.91067.21078.11086.41096.71104.01114.41127.61131.61140.6

Moderately to heavily bioturbated claystoneClaystone and silty claystoneSlightly to moderately bioturbated silty claystoneSilty claystone and glauconite sandy siltstoneSilty claystoneModerately bioturbated silty claystoneModerately bioturbated silty claystoneModerately bioturbated silty claystoneModerately bioturbated silty claystoneSlightly bioturbated silty claystoneModerately bioturbated silty claystoneSilty claystoneSilty claystoneHomogeneous silty claystoneSilty claystone and clauconitic silty claystoneModerately to heavily bioturbated silty claystoneSlightly to moderately bioturbated silty claystoneSilty claystone and dolomitic clayey siltstoneModerately bioturbated silty claystoneModerately to heavily bioturbated silty claystoneModerately bioturbated silty claystoneSilty claystone and glauconitic silty sandstoneModerately bioturbated silty claystoneModerately bioturbated silty claystoneSlightly to moderately bioturbated silty claystoneModerately bioturbated silty claystoneSlightly to moderately bioturbated silty claystoneClayey siltstone, silty claystone, glauconitic sandy siltstone and glauconitic silty sandstoneHeavily bioturbated nannofossil clayey chalk with foraminiferHeavily bioturbated nannofossil clayey chalk with foraminiferHeavily bioturbated nannofossil clayey chalk with foraminiferHeavily bioturbated nannofossil clayey chalk with foraminiferSlightly to heavily bioturbated nannofossil clayey chalk with foraminiferaSlightly to heavily bioturbated nannofossil clayey chalk with foraminiferaHeavily bioturbated porcellanitic nannofossil chalkHeavily bioturbated calcareous porcellanite and porcellanitic nannofossil chalkHeavily bioturbated calcareous porcellanite

0.731.821.951.852.172.492.402.612.323.552.842.252.303.213.193.313.212.812.553.012.813.022.452.552.593.142.482.551.390.500.42

0.45

0.770.260.53

5.85.03.94.03.77.32.54.65.1

10.48.39.0

11.714.89.9

18.810.316.121.87.34.6

25.48.29.9

23.512.213.732.940.538.933.433.843.553.542.045.1

0.270.821.711.732.081.961.772.262.002.481.591.881.781.381.321.491.511.691.871.201.551.731.371.731.361.241.321.150.440.230.230.230.240.240.070.050.08

Table 2. Lithology, organic carbon content, and elemental analysis data for core samples from Site 905.



TOC(wt%)

CaCO3

(wt%)Sulfur(wt%)

150-905 A-1H-2, 55-602H-2, 49-553H-4, 22-284H-1, 100-1065H-2, 8-137H-6, 10-169H-3, 30-3610H-4, 76-8211H-2, 132-13812H-1, 115-12013H-1, 110-11515H-2, 120-12616X-2, 110-11617X-3, 130-13619X-1, 120-12621H-3, 10-1622H-1, 54-6623H-1, 89-10024H-1, 86-9125H-2, 100-10526H-1, 100-10627X-4, 30-3628X-2, 90-9529X-2, 130-13630X-1, 140-14631X-1, 110-11532X-2, 110-11633X-1, 124-13034X-1, 14-2035X-4, 130-13636X-2, 110-11637X-2, 110-12238X-2, 114-12539X-4, 27-3340X-3, 60-6741X-3, 19-2542X-2, 36-4143X-3, 90-9644X-6, 40-4645X-3, 37-4246X-3, 15-21

22.131.540.746.556.670.683.394.2

101.3107.6112.6128.7137.1148.4164.6184.8192.7196.6202.3213.5216.0223.8226.4235.2243.4252.8263.9272.2280.7296.0302.2311.5320.9332.5340.9350.2358.4370.1383.8388.9398.3

Silty claySilty claySilty clay with laminated sandy clayIndistinctly bioturbated silty claySilty clay and glauconite sandSlightly bioturbated silty clayClayClayHomogeneous silty claySlightly sandy silty claySilty claySilty clayClayHomogeneous clay and silty claySilty claySilty clay and sandSilty claySilty claySilty clayHomogeneous silty clayHomogeneous silty clayHomogeneous, moderately to heavily bioturbated silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, rarely bioturbated silty clayHomogeneous, heavily bioturbated silty clayHomogeneous, heavily bioturbated silty clayHeavily bioturbated silty clayHomogeneous silty clayHomogeneous, slightly bioturbated silty clayHomogeneous, slightly to moderately bioturbated silty clayHomogeneous, moderately bioturbated silty clayHeavily bioturbated silty clayHomogeneous, diatomaceous silty clay and clayey siltModerately bioturbated silty clay with foraminiferaSlightly to moderately bioturbated silty clay with foraminiferaSlightly bioturbated silty clay with foraminiferaSilty clay

0.460.350.331.181.531.920.310.350.270.350.320.4S0.370.390.340.310.360.420.351.521.481.191.331.381.361.401.511.090.931.041.110.891.180.960.810.920.790.750.810.901.04

10.78.86.0

10.99.01.87.78.1

12.87.78.17.48.2

10.07.67.99.68.69.82.82.0

11.78.3

10.410.89.18.0

15.714.410.52.9

12.18.88.6

10.712.110.215.414.619.316.5

0.360.510.220.841.181.600.270.350.160.220.240.080.190.140.300.230.200.180.221.911.121.311.461.201.481.411.380.721.361.070.880.690.960.830.420.850.490.650.410.550.79

335


Table 2 (continued).



TOC(wt%)

CaCO3

(wt%)Sulfur(wt%)

47X-4, 140-14648X-5, 140-14649X-4, 35-4050X-1, 10-1651X-1, 14-2052X-6, 120-12653X-3, 20-2654X-4, 119-13255X-3, 130-14356X-3, 99-10357X-2, 96-10258X-3, 60-6559X-1, 129-13560X-6, 20-2561X-1, 31-3662X-1,20-2663X-5, 139-14664X-1, 5-1065X-5, 125-13066X-1, 17-2268X-4, 103-10869X-5, 15-2170X-4, 22-2871X-3, 119-12572X-4, 15-24

410.7421.9428.6433.4443.1461.4465.5476.6485.9495.3503.1513.8521.2537.2539.4549.0565.9568.2585.0587.6611.6622.4630.7639.8649.8

Homogeneous, slightly bioturbated silty clay with foraminiferaHomogeneous silty clay with foraminiferaSlightly to rarely bioturbated silty clay with forminiferaHomogeneous silty claySlightly bioturbated silty clayHeavily bioturbated to homogenous silty clayModerately to heavily bioturbated silty clayHomogeneous silty claySilty clay, homgenized, scattered pyriteSlightly to moderately bioturbated silty clayHomogeneous silty clayHeavily bioturbated to homogeneous clayey siltModerately bioturbated clayey siltHomogeneous, moderately bioturbated clayey silt and clayey silt/sandSlightly to moderately bioturbated silty clay and sandy silty claySlightly to moderately bioturbated silty clay and conglomerateConglomerate and silty clayConglomerate, silty clay and carbonate-cemented siltstoneHomogeneous to slightly bioturbated silty clayHomogeneous to slightly bioturbated silty clayHomogeneous to slightly bioturbated silty claySilty clay and mud-clast conglomerateHomogeneous to slightly bioturbated silty clayModerately to heavily bioturbated slightly silty clayModerately bioturbated silty clay with diatoms and nannofossils

1.040.880.79ü.710.760.830.910.761.111.311.681.101.211.101.581.101.251.680.761.131.471.451.300.990.97

15.114.524.211.819.717.28.5

15.56.13.51.52.32.71.33.33.75.95.15.76.77.62.28.7

11.117.4

0.800.760.480.390.480.490.720.810.991.641.191.221.061.441.092.101.791.400.930.971.410.821.230.62

Table 3. Results of Rock-Eval pyrolysis for selected sediments from Site903.


Depth(mbsf)

HI(mgHC/gTOC) (mgCO2/gTOC)

150-903 A-1H-4, 94-10013H-4, 94-10035X-6, 10-1653X-4, 90-9655X-4, 40-4662X-6, 96-10272X-5, 20-25

150-903C-20R-5, 100-10334R-1,50-5541R-4, 33-3958R-6, 36-41

5.44119.37305.50477.00495.80566.96660.60

771.61901.20972.33

1127.62

12138

129176184329240

244289

23

2522701728266

146100

1068177

356446416420420424423

422417413

Note: HI = Hydrogen Index and OI = Oxygen Index.

the sediment samples from the upper slope of the New Jersey conti-nental margin (477.0 mbsf, middle Miocene) is shown in Figure 7.The chromatogram demonstrates the abundance of long-chain alco-hols of terrestrial origin that range from C17 to C32 and have a maxi-mum at C28. They show a strong dominance of even carbon numberhomologs, and their absolute concentrations range up to 400 µg/gTOC. Also present is a complex mixture of steroidal alcohols, char-acteristic for a contribution of mainly marine organisms, with carbonskeletons from C27 to C30 and different positions of double bonds.Among the major constituents, 4α,23,24-trimethyl-5α(H)-cholest-22-en-3ß-ol (dinosterol) and 24-methylcholesta-5,22-dien-3ß-ol canbe ascribed to an origin from dinoflagellates and diatoms, respective-ly (Volkman, 1986). The presence of 24-ethylcholest-5-en-3ß-ol andits saturated analog (k and 1 in Fig. 7) is characteristic for organicmatter from higher land plants but may also bear a (minor?) marinesignature (Volkman, 1986).

The variations of absolute concentration with depth of three se-lected sterols are shown in Figure 8. There is not a steadily varyingdepth trend, but a tentative comparison (because of small samplenumber) with times of low sea level, as given by Miller and Mountain(1994), indicates that 4α,23,24-trimethyl-5α(H)-cholest-22-ene-3ß-ol has significantly lower concentrations at times of glaciation thanin the other sediment sections. The opposite trend can be seen in the

concentration of 24-ethylcholest-5-ene-3ß-ol, which may be charac-teristic for an increased supply of terrigenous organic matter by rivertransport to the outer continental shelf during times of low sea level.

n-Fatty acids

A distribution of n-fatty acids was observed, in all investigatedsamples, with a strong predominance of even carbon number ho-mologs. Typical is a maximum at C16 for marine organic matter andat C28 for terrigenous material (Cranwell, 1974; Simoneit, 1978). Theoccurrence of long-chain fatty acids (>C22) in most of the Site 903samples reflects a continuous supply of remnants of higher landplants. A series of short-chain (C14-C18) saturated and unsaturatedfatty acids, which are presumably derived from marine algae, wasrecognized mainly in sediments of the middle and lower Miocenesections. Figure 9 shows the fatty acid distributions and absolute con-centrations of individual compounds for two selected samples fromthe upper and the lower Miocene as examples of terrestrially and ma-rine influenced fatty acid distributions, respectively.

Ketones

Long-chain di- and triunsaturated ketones were detected in each ofthe selected sediment samples from Site 903, and they were used todetermine the alkenone unsaturation index (Uk

37) for reconstructionof paleo-sea-surface temperatures (Brassell, 1993; Prahl and Wake-ham, 1987; Conte et al., 1992). The amounts of C37:2 and C37:3-alk-enones in all samples are relatively small, ranging from 2 to 15 µg/gTOC. The paleo-sea-surface temperatures calculated from the Uk

37 in-dices based on the calibration of Prahl and Wakeham (1987) aregraphically represented in Figure 10. Other calibrations (e.g., Conteet al., 1992) lead only to small differences in absolute values whichare not significant in view of the generally high temperature levelthroughout the entire sedimentary sequence. For the younger sedi-ment sections, this high-temperature level of the oceanic surface wa-ter in the geological past is certainly caused by the proximity of thedrilling location to the Gulf Stream, which transports warm surfacewater northwards along the east coast of the United States. For theolder sediments, this may indicate that a similar oceanic surface cur-rent has existed even before the Middle American land mass separat-ed the Atlantic Ocean completely from the Pacific Ocean.

General caution is necessary when using the alkenone ratios fordetermination of sea surface temperatures over longer periods of geo-logical time, because Uk

37 calibrations are based on the natural prod-

336


90 T

119 199 305 377 477 496 567 660

depth (mbsf)

771 901 972 1058 1127

aliphatic HC •ffl aromatic HC • NSO asphaltenes D sulfur

Figure 4. Histogram representation of gross extract fractions (including elemental sulfur) for 14 selected sediments from Site 903.

uct chemistry of the extant coccolithophore Emiliania huxleyi at dif-ferent water temperatures. The fossil record of this organism datesback about 250 ka, which is only a short period compared with the45-Ma age (middle Eocene) of the oldest sediments recovered on theNew Jersey continental margin during Leg 150. According to inves-tigations of Marlowe et al. (1990), the morphological precursors ofEmiliania huxleyi in the Gephyrocapsaceae family extend into theEocene and were able to produce long-chain alkenones. There is noinformation for these organisms, however, on their adaptation of alk-enone composition to growth temperature. Thus, the data providedhere are completely based on the assumption of a conservative bio-chemistry of this family of organisms over many millions of years.

The drastic decrease of calculated water temperature to 3°C at asediment depth of 1057 mbsf is conspicuous. This temperature valueis caused by the absence of the C3 7 : 2 alkenone in the sample investi-gated. Possibly, this occurred by an unusual diagenetic alteration ofthe alkenone assemblage. Further investigations of adjacent sampleswill have to clarify this potential.

CONCLUSIONS

The sediments recovered during Leg 150 on the continental mar-gin off New Jersey, spanning a range of 45 Ma, were obviouslystrongly influenced by a supply of terrigenous organic material. Vari-ations in total organic carbon content are probably related to changesin the conditions for organic matter preservation in the sediments.This may be a consequence of fluctuations in the intensity of oxygen-rich deep water currents at the continental margin over geologicaltimes. Relatively low hydrogen indices are consistent with the pres-ence of (partly oxidized) terrestrial material and also confirm strongreworking of labile marine organic matter by sulfate-reducing andmethanogenic bacteria, as indicated by the presence of up to 2% ofsulfur and of abundant methane in the sediments.

Inspection of the aliphatic hydrocarbons corroborates the influ-ence of terrigenous material caused by the dominance of higher plantwax alkanes. Elevated concentrations of sterenes and pentacyclic tri-

terpenes were observed in sections where conditions were more fa-vorable for preservation of labile marine organic matter (particularlyin the middle and lower Miocene and in the Oligocene). The presenceof hopanoids, mainly derived from bacteria, indicates a strong micro-bial reworking of the primary organic matter.

Molecular indicators for the presence of terrigenous organic mat-ter were also found in the polar extract fractions (e.g., by the domi-nance of long-chain n-alcohols and n-fatty acids in many samples).Again, a carbon number shift to lower homologs indicates the preser-vation of higher relative amounts of marine organic matter. In the al-cohol fraction, most steroids, including 4oc,23,24-trimethyl-5α(H)-cholest-22-en-3ß-ol and 24-methylcholesta-5,22-dien-3ß-ol, werefrom marine organisms. A variation in concentration of these com-pounds with depth indicates changes in the supply of terrigenous or-ganic matter, probably caused by sea-level fluctuations.

Paleo-sea-surface temperatures calculated from alkenone unsat-uration indices showed a high temperature level off the present coastof New Jersey for the entire geological time span covered by the sed-imentary section drilled during Leg 150. This indicates the persis-tence of the Gulf Stream and an older analogous warm current in thisregion.

ACKNOWLEDGMENTS

We are grateful to Dr. Barbara Scholz-Böttcher (ICBM) for sup-port in GC/MS analysis. We thank Dr. Richard W. Murray (BostonUniversity) for his thorough review and helpful comments. Financialsupport was provided by the Deutsche Forschungsgemeinschaft(DFG, Bonn), Grant No. Ru 458/8.

REFERENCES

Amos, A.F., Gordon, A.L., and Schneider, E.D., 1971. Water masses and cir-culation patterns in the region of the Blake-Bahama Outer Ridge. Deep-SeaRes. Part A, 18:145-165.

Brassell, S.C., 1985. Molecular changes in sediment lipids as indicators ofsystematic early diagenesis. In Eglinton, G., Curtis, CD., McKenzie,

337


D.P., and Murchinson, D.G. (Eds.), Geochemistry of Buried Sediments.Philos. Trans. R. Soc. London A, 315:57-73.

-, 1993. Applications of biomarkers for delineating marine paleocli-matic fluctuations during the Pleistocene. In Engel, M.H., and Macko,S.A. (Eds.), Organic Geochemistry: Principles and Applications: NewYork (Plenum), 699-738.

Bray, E.E., and Evans, E.D., 1961. Distribution of n-paraffins as a clue torecognition of source beds. Geochim. Cosmochim. Acta, 22:2-15.

Conte, M.H., Eglinton, G., and Madureira, L.A.S., 1992. Long-chain alk-enones and alkyl alkenoates as palaeotemperature indicators: their pro-duction, flux and early sedimentary diagenesis in the eastern NorthAtlantic. Org. Geochem., 19:287-298.

Cranwell, P.A., 1974. Monocarboxylic acids in lake sediments, indicators,derived from terrestrial and aquatic biota, of paleoenvironmental trophiclevels. Chem. Geol., 14:1-14.

Eglinton, G., and Calvin, M., 1967. Chemical fossils. Sci. Am., 216:32-43.Espitalié, J., Laporte, J.L., Leplat, P., Madec, M., Marquis, F., Paulet, J., and

Boutefeu, A., 1977. Méthode rapide de caractérisation des roches mères,de leur potentiel pétrolier et de leur degré devolution. Rev. Inst. Fr. Pet,32:23-42.

Heezen, B.C., Hollister, CD., and Ruddiman, W.F., 1966. Shaping of thecontinental rise by deep geostrophic contour currents. Science, 152:502-508.

Kolattukudy, P.E., 1976. Chemistry and Biochemistry of Natural Waxes:New York (Elsevier).

Marlowe, I.T., Brassell, S.C., Eglinton, G., and Green, J.C., 1990. Long-chain alkenones and alkyl alkenoates and the fossil coccolith record ofmarine sediments. Chem. Geol, 88:349-375.

McCave, I.N., and Tucholke, B.E., 1986. Deep current-controlled sedimenta-tion in the western North Atlantic. In Vogt, P.R., and Tucholke, B.E.(Eds.), The Western North Atlantic Region. Geol. Soc. Am., Geol. ofNorth Am. Ser., M:451-468.

McEvoy, J., Eglinton, G., and Maxwell, J.R., 1981. Preliminary lipid analy-ses of sediments from Sections 467-3-3 and 467-97-2. In Yeats, R.S.,Haq, B.U., et al., Init. Repts. DSDP, 63: Washington (U.S. Govt. PrintingOffice), 763-774.

Miller, K.G., and Mountain, G.S., 1994. Global sea-level change and theNew Jersey margin. In Mountain, G.S., Miller, K.G., Blum, P., et al.,Proc. ODP, Init. Repts., 150: College Station, TX (Ocean Drilling Pro-gram), 11-20.

Mountain, G.S., and Miller, K.G., 1993/94. Drilling for sea-level history onthe New Jersey transect. Oceanus, 36:116-119.

Olsson, R.K., Melillo, A.J., and Schreiber, B.L., 1987. Miocene sea levelevents in the Maryland coastal plain and the offshore Baltimore Canyontrough. In Ross, C, and Haman, D. (Eds.), Timing and Depositional His-tory of Eustatic Sequences: Constraints on Seismic Stratigraphy. Spec.Publ. Cushman Found. Foraminiferal Res., 24:85-97.

Olsson, R.K., and Wise, S.W., 1987. Upper Paleocene to middle Eocene dep-ositional sequences and hiatuses in the New Jersey Atlantic Margin. InRoss, C, and Haman, D. (Eds.), Timing and Depositional History ofEustatic Sequences: Constraints on Seismic Stratigraphy. Spec. Publ.Cushman Found. Foraminiferal Res., 24:99-112.

Owens, J.P., and Gohn, G.S., 1985. Depositional history of the Cretaceousseries in the U.S. coastal plain: stratigraphy, paleoenvironments, and tec-tonic controls of sedimentation. In Poag, C.W. (Ed.), Geologic Evolutionof the United States Atlantic Margin: New York (Van Nostrand Rein-hold), 25-86.

Philp, R.P., 1985. Biological markers in fossil fuel production. Mass Spec-trom. Rev., 4:21-28.

Poynter, J., and Eglinton, G., 1990. Molecular composition of three sedi-ments from Hole 717C: The Bengal Fan. In Cochran, J.R., Stow, D.A.V.,et al., Proc. ODP, Sci. Results, 116: College Station, TX (Ocean DrillingProgram), 155-161.

Prahl, F.G., and Wakeham, W.G., 1987. Calibration of unsaturation patternsin long-chain ketone compositions for paleotemperature assessment.Nature, 344:729-734.

Radke, M., Willsch, H., and Welte, D.H., 1980. Preparative hydrocarbongroup type determination by automated medium pressure liquid chroma-tography. Anal. Chem., 52:406-411.

Shipboard Scientific Party, 1994a. Site 903. In Mountain, G.S., Miller, K.G.,Blum, P., et al., Proc. ODP, Init. Repts., 150: College Station, TX (OceanDrilling Program), 129-205.

, 1994b. Site 905. In Mountain, G.S., Miller, K.G., Blum, P., et al.,Proc. ODP, Init. Repts., 150: College Station, TX (Ocean Drilling Pro-gram), 255-308.

Simoneit, B.R.T., 1978. The organic chemistry of marine sediments. InRiley, J.P., and Chester, R. (Eds.), Chemical Oceanography (2nd ed.)(Vol. 7): New York (Academic Press), 233-311.

Still, W.C., Kahn, M., and Mitra, A., 1978. Rapid chromatographic tech-nique for preparative separations with moderate resolutions. J. Org.Chem., 43:2923-2926.

Volkman, J.K., 1986. A review of sterol markers for marine and terrigenousorganic matter. Org. Geochem., 9:83-99.

Volkman, J.K., Allen, D.I., Stevenson, P.L., et al., 1986. Bacterial and algalhydrocarbons in sediments from a saline Antarctic lake, Ace Lake. InLeythaeuser, D., and Rullkötter, J. (Eds.), Advances in OrganicGeochemistry 1985: Oxford (Pergamon Press), 671-681.

Date of initial receipt: 13 March 1995Date of acceptance: 8 December 1995Ms 150SR-040

338


S . Oe4-

& . Oe-Φ-

Rθtθntion time (min)

Bl.Oe&,

S . Oe4-

3 . O e4-

Sq

27 d

Retention time (min)

Figure 5. Capillary column gas chromatograms of the aliphatic hydrocarbon fractions in the extractable lipids of two selected sediments from Site 903. Numbers

indicate n-alkanes by their carbon chain length. See Table 4 for other labeled compounds. Ba (behenic acid methyl ester) and Sq (squalane) denote internal stan-

dards. A. Sample 150-903A-35X-6, 10-16 cm (305.50 mbsf, Pleistocene). B. Sample 150-903C-34R-1, 50-55 cm (901.20 mbsf, middle Miocene).

339


50

J o "2O30

§!»r°, ~ 10 Illllllil•I.I.L

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

Carbon number

n-alkanes

120

100

g 80

20 . l . l • l l l l l .I1516171819 20 21222324 252627 2829 30313233 34 35

Carbon number

s•δ

13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Carbon number

IS

140

120

100

SO

60

40

20 ••l•l•l•l•l16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3132 33 34 35

Carbon number

7060

| u 50|g40§^30= 320

100 lililil.l.I

••s

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

Carbon number

• •l•l•l•l•l--••••••16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

1*5<-> 20

100

— ••l•l•l•l•l17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

3530

J U 25

SgaS•S is

3lO50

l.l.lililll.18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Carbon number

100

| O 60

W 20

o ..l.l.lll.l.l17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

30

jgaoB 15•"a

..I.lilil I17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

Figure 6. Carbon number distributions and absolute concentrations, normalized to TOC, of n-alkanes in lipid extracts of 14 selected sediments from Site 903.

340


8070

l u 6 0

g θ 50

S 4 0

•-••l•l• Λ ,15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

•-••l•l•l-l17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

14

12

I u 10Sg 8

— • • • • • • • l •IIUL.17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

5

2O 3

l•i•i.l•l. ILJ17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Carbon number

Figure 6 (continued).

Table 4. Compounds identified in the aliphatic hydrocarbon fractions of

sediments from Site 903.

Table 5. Compounds identified in the alcohol fractions of Site 903 sedi-

ments.

Peak

PrPhABCDEFGH1JKLMN0pr

QRST

Compound

pristanephytanedes-A-oleana-5( 10), 12-dienedes-A-ursa-5( 10), 12-dienedes-A-olean-12-enecholest-4-enecholest-5-ene24-methylcholest-4-ene24-methylcholest-5-ene24-ethylcholest-4-ene24-ethylcholest-2-ene24-ethylcholest-5-ene30-nor-hop-17(21)-enehop-17(21)-ene30-nor-17ß(H),21 ß(H)-hopane17α(H)-hopanefern-8-ene

30-Mor-moretanehomo-hop-17(21 )-ene17ß(H),21 ß(H)-/iomo-hopane17ß(H),21 ß(H)-^7^omo-hopane

Peak

XBaabcdef

h

j

jk1mn

Compound

phthalate (contaminant)behenic acid methylester (InjSTD)cholesta-5,22-dien-3ß-ol5α(H)-cholest-22-en-3ß-olcholest-5-en-3ß-ol5α(H)-cholestan-3ß-ol24-methy lcholesta-5,22-dien-3 ß-ol24-methyl-5α(H)-cholest-22-en-3ß-ol4-methyl-5α(H)-cholestan-3 ß-ol24-methy lcholest-5 -en-3 ß-olunknown Coα-steradienol24-ethylcholesta-5,22-dien-3ß-ol4,24-dimethyl-5α(H)-cholest-22-en-3ß-ol4-ethylcholest-5-en-3ß-ol24-ethyl-5α(H)-cholestan-3ß-ol4α,23,24-trimethylcholest-22-en-3ß-ol(dinosterol)ß-amyrin

341


lOOη

50-

RIC

20

100 η

50-

_ E+082.338

22

A I W I »

26

Λ_ . A . A.

Steroidal alcohols

28

JVi Jl

5 5 : 0 0 6 0 : 0 0 6 5 : 0 0 7 0 : 0 0 JWU>O 8 0 : 0 0 8 5 : 0 0 ^ 9 0 : 0 0

\

\

k V E+081 . 1 3 1

7 6 : 0 0 7 8 : 0 0 8 0 : 0 0 8 2 : 0 0 8 4 : 0 0 8 6 : 0 0 8 8 : 0 0

Retention time (min)

Figure 7. Partial reconstructed ion chromatogram of the alcohol fraction of the lipid extract of Sample 150-903A-53X-4, 90-96 cm (477.00 mbsf, upper

Miocene) showing the sterol region. See Table 5 for compound identification.

342


Concentration of 4,23,24-trimethyl-5 (H)-cholest-22-en-

3ß-ol(µg/gTOC)0 20 40 60 80

0 •k ~i 1 1 1

200

400

(mbsf)

800

1000 -

1200

Concentration of 24-methylcholesta-5,22-dien-3ß-ol (µg/g TOC)

0 20 40 60 80 100b 1 —H 1 1

Concentration of 24-ethyIcholest-5-en- Times of sea-level3ß-ol (µg/g TOC) lowstand

0 5 10 15 20

Figure 8. Downhole trends of absolute concentrations, normalized to TOC, for three selected steroid alcohols. Times of sea-level lowstand (Miller and Moun-tain, 1994) are indicated on the right.

12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Carbon number

B 80 T

üoH

a

ion

i

11©

70 -

60

5 0 •

40

30 -

20

10 - I1 • 1 1 1 1 1 1 1 •m—m—a—rm—•—

12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Carbon number

Figure 9. Carbon number distributions and absolute concentrations of saturated (closed bars) and monounsaturated fatty acids (open bars) in two selected sedi-ments from Site 903. A. Sample 150-903A-55X-4, 4 0 ^ 6 cm (495.80 mbsf, upper Miocene). B. Sample 150-903C-41R-4, 33-39 cm (972.33 mbsf, lowerMiocene).


0

0

200 ->

4 0 0 -

43 6 0 0 -

8 0 0 -

1 0 0 0 -

1200

upperMiocene

Si

lowerMiocene

upperOligocene

upperEocenemiddleEocene

10I

Figure 10. Paleo-sea-surface temperature on the New Jer-sey continental margin calculated from alkenone unsatura-tion data based on the calibration of Prahl and Wakeham(1987).

344

Documents

18. ORGANOFACIES VARIATIONS IN SEDIMENTS FROM THE ...€¦ · 1986). This well mixed and oxygen-rich water mass affects the accu-mulation of labile organic material, so that only