山东车西地区沙三、沙四段界线之我见

山东车西地区沙河街组沙三、沙四段之间发育一套油泥岩“尾巴”段地层，其中沙三、沙四段的标志化石混生，在层位归属上一直存在分歧。通过标志化石组合特征的分析对比，并综合层序地层学、地震地层学、岩石地层学、生物地层学以及岩电组合特征的研究，认为沙四段化石的延续是早期古生物分子的孑遗，沙三段标志性化石的产生是古生物新成员的先驱，以生物地层学进行层位划分应以标志化石新成分的出现作为一个新的时代阶段的开始，而油泥岩“尾巴”段的层序地层特征、岩石地层和岩电特征等均趋向于沙三段，所以将其划归为沙三段比较合适。

Remarks on the Boundary Between the Member 3 and Member 4 of the Shahejie Formation in the Chexi Area,Shandong

Between the Member 3 and Member 4 of the Shahejie Formation in the Chexi area of Shandong is developed a suite of oil mudstone “fail” interval in which there are mixed index fossils contained either in the Member 3 or in the Member 4.The age of this interval has been a controversial subject for a long time.Based on the analysis and comparison of the characters of the index fossil assemblages and combined with the studies of the sequence stratigraphic, seismic stratigraphic, lithostratigraphic,biostratigraphic characters and the data on electrical properties if seens suitable to class the “fail” interval as the Member 3 of the Shahejie Formation.