Characteristics and evolution of the late Permian “source-to-sink” system of the Beisantai area in the eastern Junggar Basin, NW China

During the TST stage, the source area atrophies and produces a continued transgressive depositional characteristic of the “source-to-sink” system. Fan deltas dominate the system in the steep paleogeomorphological setting. During the RST stage, the source area expands and make the system expand. Beach bars dominate the system in the gentle paleogeomorphological setting. [Display omitted] •Evolution of source area in a continental foreland basin system and its sediment discharge are investigated.•Transfer system and sedimentary responses are built and linked with source area evolution.•The “source-to-sink” evolution is reconstructed through an analysis of each segments in the system. Many studies have focused on the tectonic evolution and sedimentary processes of the Beisantai Uplift, NW China during the late Permian. However, the sedimentary characteristics of the area are still not well documented due to a complex tectonic evolution of the uplift and the limited distribution of core data. To understand the sedimentary evolution of this study area, a “source-to-sink” system research is adopted. First, the research redefines the sequence stratigraphic framework of the late Permian, which corresponds to a complete third-order sequence that can be further divided into a transgressive system tract (TST) and a regressive system tract (RST). Then, the integration of three-dimensional (3D) seismic reflection data, well logs, mud logs and core data provides new insights into the transportation and sedimentary processes within the “source-to-sink” system. The different characteristics of the source area, transfer system and sedimentary paleogeomorphology between the TST stage and RST stage ultimately led to significantly different sedimentary characteristics in the two stages. In the TST stage, the “source-to-sink” system exhibited a continued transgressive depositional characteristic that matched the sediment discharge evolution. The steeper sedimentary paleogeomorphology enabled the development of large-scale fan deltas with few beach bars. During the RST stage, the “source-to-sink” system had low sediment discharge and a smooth sedimentary paleogeomorphology. The “source-to-sink” system was predominantly characterized by small-scale beach bars with few fan deltas. With the decreasing level of sediment discharge and continued smoothing of the sedimentary paleogeomorphology, the beach bars expanded.