Study on sedimentary system and sedimentary model of Jurassic in foreland basin of western Sichuan

Jurassic in western Sichuan foreland basin is of great exploration and development potentials.However,sedimentary facies of the study area was relatively seldom noted.According to the lithological association,rock color,sedimentary structure and other factors,the author deemed that Jurassic System in western Sichuan foreland basin could be divided into four sedimentary systems,they were alluvial fan,rivers,deltas and lakes,and the characters of the sedimentary sub-facies in depositional system were studied in details.Jurassic System in western Sichuan foreland basin belonged to continental deposition,and three fan depositional models were deposited as a whole,that was,by the basin margin alluvial fan through river alluvial plain to the delta and then the shallow lake to the semi-deep lake.Through a comprehensive study on sedimentary facies and sedimentary structures of the study area,alluvial fan-river-delta-lake sedimentary model was mainly developed in the area.