Dinoflagellate Cyst Biostratigraphy Of Eocene In Duina,Yadong,Tibet

The Tibetan Plateau located in the southern part of the Asian continent and known as the "roof of the world" and the "third pole" was caused by the collision between the India plate and the Asian plate.The uplift of the Himalayas and the Qinghai-Tibet Plateau has had a profound impact on the changes in global geology,geochemistry and climate,so Chinese and foreign scholars have paid great attention to the collision between the Eurasian plate and the Indian plate.But there is still a lot of controversy about the starting time of the collision.The study of the closing time of the Tethys Ocean can provide the most direct constraint for the start time of the collision between the Eurasian plate and the Indian plate.The era of the highest marine strata in the region represents the time of the closure and the full collision of the Tethys.In China,most of the Paleogene strata are continental sedimentary,and the marine paleoclimatic strata are only developed in Tibet,Xinjiang and parts of Taiwan.The southern part of the continent preserved a continuous marine paleocene to the Eocene strata,which are rich in fossils and can be used for stratigraphic division and contrast.A set of well-preserved Eocene marine strata developed in the East Asia Basin,which is rich in large amounts of sporopollen and dinoflagellate fossils.This paper focuses on the detailed study and identification of the fossils of the Eocene strata in the stacked reservoir,which 88 species of 63 dinoflagellate genus are identified and 4 assemblage zones are recognized as follows: Apteodinium donghaiense-Apteodinium rohmbiforme,Chalesdowniea rhombiodalis-Hystrichokolpoma salacia,Membranilarnacia variata-Wetzeliella xinjian and Cleistosphaeridium shandongense-Luxadinium elongatum assemblage zones.Based on the research and analysis of the fossils in the reservoir,it is concluded that the sedimentary period of the sandstone shale section of the study area can reach the late Eocene.