The Study On The Stratigraphic Sequence And Environment Of Cenozoic In Bashang Area, Northwest Hebei Province

The paper deals with the Cenozoic stratum in Bashang area , northwest Hebei province. Based on the data of palaeontology and isotopic age, the stratigraphic sequence of Cenozoic in Bashang area was set up. According to the lithological character and sedimantary structure character, the grain size distribution and scanning electron microscope analysis, the sedimantary environment of Cenozoic in Bashang area was discussed.. Through analysis of the sedimentary characters and characters of palaeontology and sporopollen in Bashang area , the Cenozoic palaeo-climate was reconstructed . The main conclusions of the paper as follows :1. The stratigraphic sequence of Cenozoic in Bashang area , northwest Hebei province was rearranged. There are 12 stratigraphic units in the area. From old to young , these are Kaidifang Formation of Eocene-Oligocene, Hannuoba Formation of Miocene, Shixia Formation of Pliocene, Chicheng Formation and Talakulian Formation of Mid-Pleistocene, Qian'an Formation and Malan Formation of Late-Pleistocene,, lake and marsh's deposit of Early-Holocene , lake and marsh's deposit and Zhangbei muchang sand bed of Mid-Pleistocene, lake and marsh's deposit and wash's deposit of Late-Pleistocene.2. Kaidifang Formation is deposit of lacutrine environment and Hannuoba Formation isbasic lava . Shixia Formation consist of lacutrine, residual material and slope deposit . Chicheng Formation deposited in the lacutrin environment . Talakulian Formation is moraine deposit and Qian'an Formation was formed in fluvial environment . Malan Formation was mainly formed by eolian deposit , together with slope-flood deposit . It deposited in lacutrine and marsh environment in Early and Middle Holocene . It deposited in lacutrine , marsh and fluvial environment in Late-Holocene .3. The climate of Bashang region in Eocene was warm with slightly wetwhich was...