Carboniferous Lithofacies and paleogeography of the Hexi Corridor Basins, China

Abstract The Hexi Corridor Basin Group, which is rich in Carboniferous source rocks, has become a key target for oil and gas exploration. The extensive distribution and oil and gas indications in dark mudstone within the Carboniferous strata illustrate promising prospects for good oil and gas in the region. The lithofacies and paleogeography of the Carboniferous in the Hexi Corridor Basin Group are analyzed through fieldwork, drilling and geochemistry. The Basin Group is characterized by extensive transgressive deposits. At the end of the deposition of the Yanghugou Formation, transgression over the uplifted area on the western margin of the Ordos region was ovvurring, and the Qilian Sea was connected with the North China Sea in the Ordos region. A braided river facies was superseded by a barrier-lagoon facies, accompanied by the formation of peat swamps and the subsequent formation of coal seams. In the Late Carboniferous, a meandering river facies became characteristic, while the barrier-lagoon facies was more widely developed in combined marine and continental setting. The lithofacies and paleogeography were influenced by the presence of significant faults and a paleotopography.