Sequence Stratigraphy and Sedimentary Facies Analysis of Micangshan Stratigraphic Minor-region (West Section) in South Shaanxi, China

The study area is located in the northern margin of the Yangtze craton, and the stratigraphic division belongs to the Micangshan stratigraphic minor-region in South Shaanxi. The neoproterozoic-triassic strata, dominated by the neoproterozoic-paleozoic strata, are missing the middle-upper Silurian, Devonian and carboniferous. The study area is divided into 11 main types of sedimentary facies. There are seven sequences in neoproterozoic-lower Palaeozoic and three sequences in late Palaeozoic. It is believed that the margin of the craton basin is alternately controlled by the relative active and quiet periods of tectonics, and the lithofacies shows the alternation from stagnant basin facies to shelf facies, and finally to stable carbonate platform facies.