THE STRUCTURAL STYLES AND THEIR ROLE IN HYDROCARBON ACCUMULATION OF THE YANQI BASIN, NW CHINA

The Yanqi basin,which formed on the basis of South Tianshan orogenic belt in the Mesozoic,was a pull apart one.Since the Miocene Yanqi basin has been overthrusted from north by Tianshan belt and from south by Kuluktag belt because of the Himalayan orogenic event.The Yanqi basin is now one of foreland basins.A series of stepped thrusts and fault related folds occur in the Yanqi basin.The tectonic loadings resulted from the overthrusts induce source rocks of the Jurassic coalbeds and dark argillites to maturation period for hydrocarbon generation.We proposed that Yanqi basin is a favorable one for accumulation of oil and gas.