The Sedimentary Record in Northern Qaidam Basin and its Response to the Uplift of the South Qilian Mountain at around 30 Ma  

作　　者：SONG Bowen ZHANG Kexin CHEN Ruiming WANG Chaowen LUO Mansheng ZHANG Jianyu JIANG Shangsong 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences [2]Faculty of Earth Sciences, China University of Geosciences [3]Institute of Geology and Mineral Resources, China Geological Survey

出　　处：《Acta Geologica Sinica(English Edition)》2013年第2期528-539,共12页地质学报（英文版）

基　　金：supported by the Foundation of Geological Survey of China (No.1212011121261);the National Natural Science Foundation (Nos.: 40921062 and 40830212)

摘　　要：The thick, Eocene to Pliocene, sedimentary sequence in Qaidam Basin at the northern margin of the Tibetan Plateau records the surface uplift history of the northeastern Tibetan plateau. In this study, we present detailed geochemistry, heavy mineral, and clay mineralogy data of the well preserved sedimentary record in the Dahongou section in the northeast of the Qaidam Basin. The results suggest that the sedimentary sequence recorded a 30 Ma young uplift/unroofing event in the northern edge of the Qaidam Basin, which is characterized by high ZTR index value and chlorite content, and low CIW＇. The results are consistent with previous sedimentological studies of the Qaidam Basin, which indicated rapid increase of the accumulation rates around 30 Ma. Based on past thermochronological data from the mountains around the Qaidam Basin and the accumulation rates of the Cenozoic basins in the northeastern Tibetan Plateau, we infer a regional uplift and denudation event along the northeastern Tibetan Plateau during early Oligocene （-30 Ma）, indicating that the Tibetan Plateau had expanded north-eastward of the study area at that time.The thick, Eocene to Pliocene, sedimentary sequence in Qaidam Basin at the northern margin of the Tibetan Plateau records the surface uplift history of the northeastern Tibetan plateau. In this study, we present detailed geochemistry, heavy mineral, and clay mineralogy data of the well preserved sedimentary record in the Dahongou section in the northeast of the Qaidam Basin. The results suggest that the sedimentary sequence recorded a 30 Ma young uplift/unroofing event in the northern edge of the Qaidam Basin, which is characterized by high ZTR index value and chlorite content, and low CIW＇. The results are consistent with previous sedimentological studies of the Qaidam Basin, which indicated rapid increase of the accumulation rates around 30 Ma. Based on past thermochronological data from the mountains around the Qaidam Basin and the accumulation rates of the Cenozoic basins in the northeastern Tibetan Plateau, we infer a regional uplift and denudation event along the northeastern Tibetan Plateau during early Oligocene （-30 Ma）, indicating that the Tibetan Plateau had expanded north-eastward of the study area at that time.

关 键 词：heavy mineral CIW＇ Early Oligocene Qaidam Basin uplift of Tibetan Plateau 

分 类 号：P542[天文地球—构造地质学]