Cenozoic Sediments and Tectonic Evolution in the Western Qaidam Basin

It is suggested that the Qaidam basin was generated as a result of longitudinal buckling of crust,manifesting itself as a synclinal depression in Cenozoic. There is similiar deformation on the south and north parts of the basin,and exist major high-angle reverse faults at basin margins. In Paleogene,this basin linked with the adjacent intermontain Suhai and Kumukol basins. The western Qaidam basin experienced three distinct tectonic evolution stages:formation of crustal folds in the Paleocene-early Oligocene,further development of the folds during the late Oligocene to the Middle Miocene,and intense activity of fault-fold structure in later time. The deposit boundaries and sedimentary facies were controlled by every structural stage correspondingly. And both of the Suhai basin and Kumukol basin were part of the Qaidam basin during the Paleogene,which were subsequently isolated from the Qaidam basin due to basinward thrusting at basin-margin areas. The Liping area in the center and the margin areas of the basin are considered with major potential of oil and gas exploration.