The depositional architectures and geodynamics of the West Jiuquan basin, Gansu

The West Jiuquan Cretaceous basin, a monotypic petroliferous basin in Gansu is composed of alluvial fan, subaqueous gravity flow fan, fan delta, lake, fluvial depositional systems. The depositional system associations such as alluvial fan-fan delta-littoral-to shallow-lake-gravelly braided river, nearshore subaqueous gravity flow fan-moderate to deep lake-fan delta, and fan delta-moderate to shallow lake-fluvial associations record the distinctive phases of the basin evolution. The infilling sequences of the basin may be divided, in the light of isochrous surfaces, into three tectonic sequences corresponding to the initial rifting, extension and subsidence-thermal subsidence, and basin collapse and closure phases. The evolution of the basin is controlled by the distal stresses such as the waxing and waning of the mantle thermal plumes and Yanshanian movement.