东海西湖凹陷保俶斜坡平湖组层序地层分析

根据层序地层学原理,西湖凹陷保俶斜坡始新统平湖组可划分为四个层序。通过分析钻井地层、测井曲线及地层中出现的有孔虫、沟鞭藻化石,对各层序进行了体系域划分。并指出在斜坡带不同部位、不同时期,沉积环境存在着差异,即第Ⅰ层序～第Ⅱ层序平中地区为海湾沉积环境、平北地区为淡化海湾沉积环境;第Ⅲ层序均为期坪～沼泽沉积,但受海侵的程度存在差异;第Ⅳ层序均已演化为河控三角洲环境。

Sequence Stratigraphic Analysis of Pinghu Formationin Baoshu Slope of Xihu Sag in the East China Sea

According to the principle of sequence stratigraphy , Pinghu formation of Eocene can be divided into four sequences. Each sequence can be diveded into system tracts based on the lithology, log, marine fossil of foraminifera and dinoflagellate. Different sedimentary environments occur at different parts of the slope in every sequence. The first and second sequences are bay sedimentary environment in the south and middle of Baoshu slope and fresh bay sedimentary environment in the north of Baoshu slope. The third sequence is tidal flat-marsh sedimentary environment, but degree of transgression differs at different parts. The fourth sequence is river delta sedimentary environment in the entire Baoshu slope.