Evolution of Qaizhong Fault and its effects on the basin formation in Qaidam Basin

The main controlling factors for the structural evolution of Qaidam Basin are always the focus for the researchers in China.This study on the practical information shows that there is a regional Qaizhong Fault from east to west in Qaidam Basin.This fault was formed during the Proterozoic Era and composed of several mid-small faults in some areas.It becomes a crust suture zone between the craton of South Qaidam and the hyperplasia of North Qaidam.This crust suture zone is one of the main faults affecting the change of the deposition center in Qaidam Basin.Since the Mesozoic Era,Qaizhong Fault has become a part of Altyn Strike-slip Fault with characteristics of slipping while depositing.The topography,formations,structure and gravity magnetic field are obviously different along both sides of Qaizhong Fault.The real Qaidam Block was separated from Qaidam-Qilian Block in the Caledonian and experienced two times of basin formation in Hercynian and Yanshanian-Himalayan periods.Qaizhong Fault controlled the processes of basin formation,evolution and hydrocarbon enrichment.