LITHOFACIES PALEOGEOGRAPHY OF FUXIAN STAGE IN EARLY JURASSIC IN ORDOS BASIN

Based on the synthetic study of outcrops and drilling section data, it is proposed that the fan fluvial sedimentation of Fuxian Stage was closely related to paleomorphology. Its paleogeography was controlled by five rivers occurred on the paleo structural plane after Indosinian movement.Fans existed in Ganshan and Qingxi river valleys and the fans showed progradating charecteristics. Among the five rivers, Jinshan river channel was braided arenaceous fluvial channel, and others were low curvature arenaceous fluvial channels. Point bar and flood plain sedimentation was widespread. It is showed that the flow direction of Ganshan fluvial was from west to east and the complex Fuxian mudstone was product of flood plain microfacies deposited at late period of fuxian Stage.