摘要
古湖岸线是历史时期湖平面与古陆地的交线，是陆上和水下沉积的分界线，确定古湖岸线的位置对于油气勘探起着重要的指导作用。采用有机岩石学方法对鄂尔多斯盆地北部地区盒8段暗色泥岩显微组分特征和有机岩石学特征进行了深入研究，结果显示三角洲平原相泥岩显微组分以镜质组为主，泥岩有机相为陆地森林沼泽相，前缘相泥岩显微组分则以无定形体组分富集为特征，有机相为覆水森林沼泽相和开阔水体相。结合泥岩颜色平面分布特征，确定了盒8期古湖岸线位置及湖岸线摆动区。
Paleo-lake shoreline was a boundary line between the lake plane and paleo-land in the historical period, and also the boundaries between onshore and underwater deposition. Determination of the paleo-lake shoreline location has an important role in guiding the exploration for oil and gas. The maceral and organic petrological characteristics of melanocratic mudstone of He8 Member in northern Ordos Basin are deep studied in this paper by adopting a method of organic petrology. The results show that the macerals of delta plain facies mudstone take vitrinite as the main; the mudstone organic-facies are terrestrial forest-swamp facies. Maceral of the front facies mudstone is characterized by enrichment of amorphous-body components. The organic facies is overlying water forest-swamp facies and open water facies. The location of paleo-lake shorelines and swing area of the shorelines during the He8 stage are determined with combination of the planar distribution of the mudstone colors.
