Mesozoic sedimentary characteristics and tectonic evolution in the eastern part of the Qiangtang basin

Abstract：The basement of the eastern Qiangtang basin is composed of the pre-Carboniferous Jitang Group-complex and the sedimentary cover of the basin consists of Late Paleozoic-Cretaceous strata. In the basin cover, Mesozoic marine strata are widespread, there area a variety of sedimentary sequences and Mesozoic tectono-paleogeographic transition occurred frequently. The Mesozoic basin can be divided into three tectonic units: the north and south Qiangtang depressions and Tanggula uplift, and in each tectonic unit several secondary depressions and uplifts of different stages may be distinguished. The development and evolution of the eastern Qiangtang basin, which are controlled by the plate junction zones at the north and south sides and constrained by differential activities of various blocks bounded by the divisional fault zones inside the basin, progressed through the Late Triassic foreland basin stage, Early-Mid Jurassic“northern Qiangtang”extensional foreland basin stage, Jurassic-Early Cretaceous Doima passive continental-margin basin development stage and later foreland basin development stage and Late Cretaceous southern Qiangtang intermontane compressional-depressed basin evolution stage. In essence, the eastern Qiangtang basin is a huge superposed basin formed by order stacking of prototype basins in different periods of time.