东疆上二叠统烃源岩中的短链甾烷

Research on Short-chain Steranes in Source Rocks from Upper Permian,Eastern Xinjiang

为了研究东疆地区主要盆地上二叠统烃源岩的有机地球化学特征,对三塘湖盆地和准噶尔盆上二叠统芦草沟组和平地泉组的6块烃源岩抽提物的饱和烃进行GC-MS分析,在m/z217质量色谱图中检测到C19-21~C26短链甾烷系列化合物。对该系列化合物地球化学特征的研究表明,东疆主要盆地在上二叠统具有相似的沉积环境、母源和生烃特征,均以干旱条件下的咸化湖相环境为主;水体中藻类等低等水生生物和微生物发育;这些原生有机质在沉积过程中经历过微生物改造作用;原始有机质与微生物降解的产物在地质条件得以共同保存,成为生烃的母质。

In order to understand the organic geochemistry feature of the source rocks,GC-MS analyses on saturated hydrocarbons in the Upper Permian Lucaogou & Pingdiquan Formation source rocks from the Junggar and Santanghu Basins in Eastern Xinjiang were performed. Complete short-chain steranes with C19-21~ C26 R were detected in mass chromatograms at m /z217. The detection of these compound series indicates that a flourish of sponges,algae( e.g.,red algae and Gloeocapsomorpha prisca) and other lower aquatic organisms existed in saline waters under arid conditions. These original organic materials experienced severe bacterial biodegradation during the early deposition stage;the original organic matter and the products of microbial degradation were preserved together and became precursors of hydrocarbon generation.