Generation and migration of low-molecular weight hydrocarbons in sediments from Site 511 of DSDP/IPOD Leg 71, Falkland Plateau, South Atlantic

Author(s): Schaefer, R. G.; Leythaeuser, Detlev; von der Dick, Hans
Author Affiliation(s): Primary:
KFA Jülich, Inst. Erdöl und Org. Geochem., Jülich, Federal Republic of Germany
Univ. Louis Pasteur, Inst. Chem., France
Br. Natl. Oil Corp., United Kingdom
Shell Can., Canada
Univ. Bristol, Org. Geochem. Unit, United Kingdom
Akad. Nauk SSSR, USSR
Inst. Chem. Kerforsch., Federal Republic of Germany
Inst. Fr. Pet., France
BP Res. Cent., United Kingdom
RWTH Aachen, Inst. Geol., Geochem. und Lagestatten Erdols und Kohle, Federal Republic of Germany
Volume Title: Advances in organic geochemistry, 1981
Volume Author(s): Bjorøy, M., editor; Albrecht, C.; Cornford, C.; de Groot, K.; Eglinton, G.; Galimov, E.; Leythaeuser, Detlev; Pelet, R.; Rullkötter, J.; Speers, G.
Source: Proceedings of the International Meeting on Organic Geochemistry, Vol.10, p.164-174; Tenth international meeting on organic geochemistry; Advances in organic geochemistry, 1981, Bergen, Norway, Sept. 14-18, edited by M. Bjorøy, C. Albrecht, C. Cornford, K. de Groot, G. Eglinton, E. Galimov, Detlev Leythaeuser, R. Pelet, J. Rullkötter and G. Speers. Publisher: Wiley & Sons, Chichester-New York, International. ISBN: 0-471-26229-3
Note: In English. 20 refs.A Wiley Heyden publication; illus. incl. 2 tables, sect., strat. col., sketch map
Summary: Concentration and detailed composition of low molecular weight hydrocarbons have been measured in sediment core samples from 160-650 m depth. Analysis was carried out by a combined hydrogen stripping/thermovaporization method and subsequent capillary gas chromatography. Total light hydrocarbon yields, which represent both hydrocarbons dissolved in the pore water and those adsorbed on clay minerals, vary from 24 ng/g of dry weight sediment in the Coniacian/Upper Santonian zeolitic claystones to 17 400 ng/g in the Upper Jurassic 'black shales'. The concentration encountered in the lowermost part of the 'black shales' is in accordance with the quantity of light hydrocarbons generated by type-II kerogen-bearing petroleum source beds in an early maturity stage. Generally, low-molecular weight hydrocarbons in Hole 511 are formed in situ and remain at their place of formation. Indications for a redistribution of light hydrocarbons are observed around the Tertiary/Cretaceous unconformity, and at the contact between the 'black shales' and the overlying chalks and claystones. Redistribution patterns are interpreted to reflect a combination of several processes: bulk migration of light hydrocarbons along with moving compaction waters, replenishment of the depleted intervals by mobile, gas-range hydrocarbons possibly by diffusion, and the enrichment of polar compounds such as benzene and toluene in those intervals where an excessive flow of compaction water has occurred. (Auth.)
Year of Publication: 1983
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 29 Economic Geology, Energy Sources; Areal studies; Argillite; Aromatic hydrocarbons; Atlantic Ocean; Atlantic Ocean Islands; Benzene; Black shale; Clastic rocks; Clay mineralogy; Continental shelf; Cretaceous; DSDP Site 511; Deep Sea Drilling Project; Economic geology; Falkland Islands; Falkland Plateau; Geochemistry; Hydrocarbons; IPOD; Jurassic; Kerogen; Leg 71; Macerals; Maturity; Mesozoic; Oceanography; Organic compounds; Organic materials; Petroleum; Sedimentary rocks; Source rocks; South America; South Atlantic; Toluene; Vitrinite
Coordinates: S510017 S510017 W0465818 W0465818
Record ID: 1983062749
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