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Geochemistry of the alginite and amorphous organic matter from type II-S kerogens

Organic Geochemistry

By:
, , ,
DOI: 10.1016/0146-6380(96)00048-4

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Abstract

Maceral fractions of the Type II-S kerogens from the Monterey Formation (Miocene. California. U.S.A.) and Duwi Formation (Campanian/Maastrichtian, Egypt) were separated by density gradient centrifugation. The Monterey Fm. kerogen sample was comprised chiefly of light red-fluorescing amorphous organic matter (AOM), the flash pyrolyzate of which was characterized by a predominance of alkylbenzenes, alkylthiophenes and alkylpyrroles. In contrast, the pyrolyzates of its alginite concentrate showed a highly aliphatic character, typical of this maceral, with the series of n-alkenes and n-alkanes (C6- C26) predominating. The pyrolyzate of the dominant light brown-fluorescing AOM of the Duwi Fm. kerogen had a relatively high concentration of alkylbenzenes and alkylthiophenes, while its elginite concentrate showed a more aliphatic character upon pyrolysis. There was a marked enrichment of thiophenic sulfur in the light-colored AOM of both samples (and also pyrrolic nitrogen in the case of the Monterey) relative to the alginite. The results support a bacterially-mediated, degradative origin for Type II-S amorphous organic matter, with algal remains as the primary source of the kerogen.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Geochemistry of the alginite and amorphous organic matter from type II-S kerogens
Series title:
Organic Geochemistry
DOI:
10.1016/0146-6380(96)00048-4
Volume
24
Issue:
5
Year Published:
1996
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Organic Geochemistry
First page:
495
Last page:
509
Number of Pages:
15