Sedimentary facies and litho-paleogeographic evolution during the deposition of the Yanchang formation in the late Triassic in the southeast of Ordos basin

Southeast of Erdos basin is a key study area, in order to identify the sedimentary facies and litho-paleogeographic evolution during the deposition of the Yanchang formation in the late Triassic, based on large quantities of drilling, logging, field outcrop and core data, the plane and vertical characteristics and the law of sedimentary facies has been analyzed. The study showed that Ordos late Triassic in Yanchang formation sedimentary represented a complete lacustrine basin development process. The study area developed delta facies and lacustrine facies, which are mainly shallow lake and delta front, the material source distributed in the northeast and south direction. In the article, the deposition of sedimentary facies and paleogeography is summarized, which has guiding significance for the judgment of favorable area and the following exploration.