Tectonic evolution of the Northern Qaidam basin during Mesozoic and Cenozoic eras

Qaidam basin is one of the large Mesozoic and Cenozoic basins in the Northwestern China. The Jurassic system mainly occurs in the northern area of Qaidam basin. The basin developed on the pre-Jurassic cratonic basement. Based on the Mesozoic-Cenozoic tectonic setting of the Northwestern China, the Qaidam basin evolved twice from extension to compression during Mesozoic and Cenozoic eras with more and more weaker in extention and more and more intensively in compression. The prototype basin in Jurassic was a weakly extending depression;Begining Oligocene epoch,the basin was becoming in tensively compressed and the structure distribution framework today was formed. The Jurassic petroleum system of the Northern Qaidam basin was influenced by the tectonic evolution on the formation and distribution of the petroleum,and resulted in the better potential exploration in the Eocene strata and poor in the Jurassic strata.