Sedimentary Evolution and Morphological Characteristics of Modern Lake Shoreline Delta under the Influence of Coast Current

Abstract：Lake deltas are located in the complex zone of lake and river interaction, influenced by the dual effects of material exchange between the two. There are not only climate and water level influences, but also topography and geomorphology and waves and other lake hydrodynamic influences, resulting in a more complex lake delta evolution process. To explore the sedimentary characteristics and the impact of lake dynamics during different stages of delta development under the influence of coast current, the Muhuahe Delta in Daihai Lake is taken as the study object for modern sedimentary investigations. Through the analysis of high-precision satellite photos and the interpretation of profile information collected by UAV oblique photography, the sedimentary evolution of the delta in the study area was analyzed in detail. The results show that delta deposits are developed in the eastern gentle slope zone of Daihai, and the delta front subfacies are widely distributed. The profile shows that the sand bodies are affected by strong hydrodynamics, and a large number of wave-formed structures are developed and lateral migration is obvious on the plane. Satellite remote sensing data suggest the sedimentary sand bodies' development and distribution characteristics, indicating the control of coast current in the development and evolution of the delta. The delta is asymmetric, with well-developed sand dams at the delta front, growing parallel to the shoreline. Although influenced by provenance supply, during this period, the delta is controlled by littoral currents, and its expansion toward the lake basin is suppressed. Generally, coast current plays a significant role in modifying the plane distribution and scale of the delta front sand bodies. Reservoir heterogeneity is often generated due to different dominant hydrodynamic conditions, providing a reference for further exploration into the influence of coast current on reservoir development and distribution.

Keywords: coast current; gentle slope delta; sedimentary evolution