Identification and significance of 3β-alkyl steranes in the Eogene lacustrine sediments and petroleum of China  

作　　者：WANG Guangli ZHANG Linye WANG Tieguan 

机构地区：[1]Key Laboratory for Petroleum Formation Mechanisms, Petroleum University of China, Beijing 102249, China [2]Institute of Geological Sciences, Shengli Oilfield Co. Ltd, Dongying 257015, China

出　　处：《Chinese Science Bulletin》2006年第13期1628-1632,共5页

摘　　要：Several homologous series of steranes with alkyl side chains (C1 to C4) at the 3β position have been identified in the Jiyang Eogene lacustrine deposition. It is postulated that its precursors repre sent a new class of steroids, alkylated at the C-3 po sition with a polyhydroxy n-alkane. These precursors may have been formed by the bacterial addition of a ribose sugar to ?2-sterenes, diagenetic alteration products of steroids synthesized by eukaryotes 3-alkyl steroids might substitute for hopanols in bac terial membranes. When they are present in a sam ple, the patterns of the isomer distributions of 3-alky steranes are similar to desmethyl steranes except fo lower rearranged ones. It is shown that the configu rational isomerization of 3-alkyl steranes is trending in line with that of desmethyl steranes with increasing of maturity. The abundance of 3-alkyl steranes may be controlled by the depositional environments; they are primary in saline or near shore lacustrine, mod erate in shallow lacustrine, poor in sub-deep to deep lacustrine relative to the 4-methyl steranes.Several homologous series of steranes with alkyl side chains （C1 to C4） at the 3β position have been identified in the Jiyang Eogene lacustrine deposition. It is postulated that its precursors represent a new class of steroids, alkylated at the C-3 position with a polyhydroxy n-alkane. These precursors may have been formed by the bacterial addition of a ribose sugar to △^2-sterenes, diagenetic alteration products of steroids synthesized by eukaryotes. 3-alkyl steroids might substitute for hopanols in bacterial membranes. When they are present in a sample, the patterns of the isomer distributions of 3-alkyl steranes are similar to desmethyl steranes except for lower rearranged ones. It is shown that the configurational isomerization of 3-alkyl steranes is trending in line with that of desmethyl steranes with increasing of maturity. The abundance of 3-alkyl steranes may be controlled by the depositional environments; they are primary in saline or near shore lacustrine, moderate in shallow lacustrine, poor in sub-deep to deep lacustrine relative to the 4-methyl steranes.

关 键 词：3-烃基甾烷 湖沉积 GC-MS-MS 早第三纪 

分 类 号：P618.13[天文地球—矿床学]