Release of bound aromatic hydrocarbons from late Archean and Mesoproterozoic kerogens via hydropyrolysis

被引:85
作者
Brocks, JJ [1 ]
Love, GD
Snape, CE
Logan, GA
Summons, RE
Buick, R
机构
[1] Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 USA
[2] Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA
[3] Newcastle Univ, Sch Civil Engn & Geosci, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[4] Univ Nottingham, Sch Chem Environm & Min Engn, Nottingham NG7 2RD, England
[5] Geosci Australia, Canberra, ACT 2601, Australia
[6] MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA
[7] Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA
[8] Univ Washington, Astrobiol Program, Seattle, WA 98195 USA
关键词
D O I
10.1016/S0016-7037(02)01302-9
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Hydrogen-lean kerogens (atomic H/C<0.4) isolated from the 2.5-billion-year-old (Ga) Mt. McRae Shale, Hamersley Group, at Tom Price, Western Australia, were studied via hydropyrolysis, a continuous-flow technique that degrades organic matter in a stream of high-pressure hydrogen assisted by a dispersed Mo catalyst. The hydropyrolysates yielded predominantly phenanthrene and pyrene, and higher polyaromatic hydrocarbons and alkylated homologues were generated in low relative concentrations. Saturated hydrocarbons were not detected. The molecular and carbon isotopic compositions of the hydropyrolysates are very similar to aromatic hydrocarbons obtained by solvent extraction of the host rocks. Because molecular structures covalently attached to kerogen are unaffected by contamination, this indicates that both the bound and extractable aromatic fractions are syngenetic with the host rocks. Therefore, the results of the hydropyrolysis experiments provide compelling evidence for preserved bitumen of Archean age. The very high proportion of nonalkylated polyaromatic hydrocarbons in the hydropyrolysates is consistent with hydrothermal dehydrogenation of the kerogen, and a marked concentration difference of pyrene in rock extracts and hydropyrolysates might be explained by hydrothermal redistribution of the bitumen. The kerogen and bitumen composition is therefore consistent with models suggesting a hydrothermal origin for the giant iron ore deposits at Mt. Tom Price. Comparison of the Archean samples with hydropyrolysates from immature Mesoproterozoic kerogens from the Roper Group, McArthur Basin, Northern Territory, and with pyrolysis experiments on Proterozoic kerogens in the literature suggests that Precambrian kerogens are frequently highly aromatic and lipid-poor regardless of their degree of thermal preservation. Copyright (C) 2003 Elsevier Science Ltd.
引用
收藏
页码:1521 / 1530
页数:10
相关论文
共 28 条
[1]  
[Anonymous], COMPOSITION GEOCHEMI
[2]   Biological affinities of Neoproterozoic acritarchs from Australia: microscopic and chemical characterisation [J].
Arouri, KR ;
Greenwood, PF ;
Walter, MR .
ORGANIC GEOCHEMISTRY, 2000, 31 (01) :75-89
[3]   Release of kerogen-bound hopanoids by hydropyrolysis [J].
Bishop, AN ;
Love, GD ;
McAulay, AD ;
Snape, CE ;
Farrimond, P .
ORGANIC GEOCHEMISTRY, 1998, 29 (04) :989-1001
[4]   CURTISITE, IDRIALITE AND PENDLETONITE, POLYCYCLIC AROMATIC HYDROCARBON MINERALS - THEIR COMPOSITION AND ORIGIN [J].
BLUMER, M .
CHEMICAL GEOLOGY, 1975, 16 (04) :245-256
[5]   Archean molecular fossils and the early rise of eukaryotes [J].
Brocks, JJ ;
Logan, GA ;
Buick, R ;
Summons, RE .
SCIENCE, 1999, 285 (5430) :1033-1036
[6]  
BROCKS JJ, 2001, THESIS U SYDNEY
[7]  
de Leeuw J.W., 1993, ORG GEOCHEM, P23, DOI [DOI 10.1007/978-1-4615-2890-6, 10.1007/978-1-4615-2890-6_2]
[8]   RAPID METHOD FOR SOURCE ROCKS CHARACTERIZATION AND FOR DETERMINATION OF PETROLEUM POTENTIAL AND DEGREE OF EVOLUTION [J].
ESPITALIE, J ;
LAPORTE, JL ;
MADEC, M ;
MARQUIS, F ;
LEPLAT, P ;
PAULET, J ;
BOUTEFEU, A .
REVUE DE L INSTITUT FRANCAIS DU PETROLE, 1977, 32 (01) :23-42
[9]   EFFECT OF IGNEOUS INTRUSION ON THE ORGANIC GEOCHEMISTRY OF A SILTSTONE AND AN OIL-SHALE HORIZON IN THE MIDLAND VALLEY OF SCOTLAND [J].
GEORGE, SC .
ORGANIC GEOCHEMISTRY, 1992, 18 (05) :705-723
[10]  
Hayes J.M., 1983, EARTHS EARLIEST BIOS, P93