济阳坳陷古近纪分子古生物及其沉积环境

Molecular paleontology and its depositional environment during the Eocene Jiyang depression,China

运用分子有机地球化学的理论和方法,对济阳坳陷古近纪的分子化石及其沉积环境进行系统研究。结果表明:分子化石的演变在平面上具有非均质性,在纵向上具有旋回性;沙三段和沙一段沉积时期,湖盆的规模最大,非均质性相对较小;沙四上亚段时期,盆地分割性强,非均质性也最强;透光、静止、还原的滞水层在济阳坳陷古近纪湖泊中广为发育,沟鞭藻和细菌是古近纪重要的浮游生物,颗石藻类在沙一段和沙四上亚段较为发育。

Based on the theory and methodology of molecular organic geochemistry,molecular paleontology and its depositional environment in the Eocene Shahejie formation of Jiyang depression,Bohai Bay Basin,East China,were studied.The results show that the types of molecular fossils vary significantly on level whereas cycle on vertical.Molecular heterogeneousness of member 1 and 3 of Shahejie formation（Es1,Es3） is weaker than that of the upper part of member 4（Es4^u）on level.The scale of lake basin of Es1 and Es3 is the largest,and the basin segmentation of Es4^u is strong.Photic euxinic conditions prevailed in the paleowater column during the Eocene lacustrine.Both dinoflagellates and bacteria were significant phytoplanktons in addition to coccolithophoride limited to brackish water lakes of Es1 and Es4^u.