Origin of Chang 6 thick-bedded sand bodies of the Yanchang Formation in the central Ordos basin

Abstract：The authors studied the material source, characteristics of sedimentary facies, sand control in the slope-break zone and distribution of Chang 6 sand bodies of the Yanchang Formation of the central Ordos lake basin. The source of sand bodies comes from the northeast and southwest. There are sandstone deposited by deltaic traction current action and turbidite sandstone deposited by gravitational transport. The sedimentary facies include superposed submerged distributary channels, mouth bars, distal bars and turbidite. The direction of distribution of the thick sand bodies is vertical or parallel to the lakeshore line.