Tectonic features of the orogenic-type basins and oil and gas accumulation in northwestern China

There are four petroleum basins including the Tarim,Junggar,Qaidam and Turpan-Hami basins,and a number of medium-and small-sized petroleum basins in northwestern China.Nowadays,all the basins are geographic basins formed following the uplifting of peripheral orogenic zones.The authors contend,on the basis of the tectonic effects of the orogenic zones on deposition,subsidence,tectonism and thermal activity of sedimentary basins in integration with the previous data,that the orogenesis of the peripheral orogenic zones have not only provided abundant sediments for the basins but also exerted an important effect on the formation and evolution of the structures in the basins,especially the orogenic effects on the source rocks,reservoir rocks and cap rocks as well as the trapping,migration and preservation of oil and gas.