海洋古细菌分子化石

MOLECULAR FOSSILS DERIVED FROM MARINE PALAEOBACTERIA

对贵州、云南等地古代海相沉积有机质中的烃类分布进行了GC/MS分析,检测出大量的有机化合物,这些化合物具有特定的生态环境意义,长链类异戊二烯烷烃(C_(21)～C_(40))已被证实广泛地与古细菌输入有关;30多个重排补身烷烃及C_(14)～C_(28)双环烷烃在地质体中的检出相当罕见,它们可能来源于细菌类脂体,也可能与细菌对多环萜类先质的生物改造作用有关;长链烷基环已烷的相关成分已在嗜盐细菌中发现;C_(19)～C_(40)异戊间二烯烷基三环萜烷在海洋沉积物中相当丰富,其先质为细菌衍生的类异戊二烯醇。此外,一系列甲基化环烷烃如甲基藿烷、甲基甾烷及甲基补身烷的广泛存在也被认为是细菌活动的证据,对古代尤其是震旦纪及早古生代地层中烃类分布的研究,为细菌微生物参与沉积有机质构成及成烃演化提供了重要依据,这类有机质应该是很有潜力的生烃母质。

Numerous organic compounds in palaeomarine sedimentary organic matter from Guizhou and Yunnan provinces have been identified by computerized GC-MS. These compounds ,being able to implement ancient ecological environments, include C21-C40 acyclic isoalkanes, C19-C10 alkyl tricyclic terpanes , C16-C24 mono-methyl chain alkanes, 33 kinds of alkanes with a dri-rnane-skeleton and C14-C28 bicyclic alkanes, as well as methylated cyclic alkanes. All of these properties are attributed to the marine-derived source of bacteria deposited under higher reducing conditions. The studies on the hydrocarbon distribution in ancient strata, especially Sinian and Lower Palaeozoic, provide an important evidence of bacteria micro-organisms which participated in the composition of sedimentary organic matter and hydrocarbon generation.