The A'nyemaqen ophiolite belt marks the suture after closure of the paleo-Tethys. In this region, four types of volcanic rocks related to ocean-floor spreading and plate subduction have been recognized.They are, from south to north, oceanic floor basalt (OFB), island arc volcanic rocks (IAV), back arc basin lavas (BAB) and post---collision volcanic rocks (PCV).The plate tectonic regime suggests the subduction sense from south to north. The spreading of the A'nyemaqen oceanic basin started at least as early as late Carboniferous (308Ma) and the closure probably took place during early Triassic. The IAV, BAB and PCV were formed respectively in late Permian (260 Ma), in early-middle Triassic, and in late Triassic. Several large-sized ductile sinistral strike slip fault zones, extending hundreds to thousands of kilometers along the suture or in the north, were initially formed during early to late Triassic.They include the South Margin Fault Zone of East Kunlun (200～220 Ma), the Altyn Tagh Fault Zone (220～230 Ma), and the North Qaidam Fault Zone（240～250 Ma）.These strike slip faults were most likely genetically related to the oblique subduction and collision of the paleo-Tethyan ocean basin, particularly in the period of exhumation of subducted plate or uplift of the overthrust plate, a period when post-collision magmatism and volcanism were active.