Mesozoic Cenozoic Sedimentary Facies in Chalangla Area, Qiangtang Basin, Tibet

Oil gas formation and accumulation is related to sedimentary facies. Based on the field remote sensing date, the Mesozoic Cenozoic sedimentary condition in Chalangla area, Qiangtang Basin is studied for the evaluation of oil and gas potential. It is shown that there are two types of rock:clastic rock and carbonate rock;they are classified into 7 major facies (neritic facies, carbonate platform facies,littoral facies, delta facies, estuarine facies,fluvial facies and alluvial fan facies),18 subfacies and many microfacies. Marine continental transition facies is dominant in Upper Triassic sedimentary in wide range, and it is a regression cycle;neritic facies in Middle Jurassic is developed, marine continental transitional facies is main in Upper Jurassic; restricted carbonate platform is developed in Lower Cretaceous, and piedmont alluvial fan is developed in Upper Cretaceous.