Internal Architectural Patterns of Bar Fingers Within Digitate Shallow-Water Delta: Insights from the Shallow Core, GPR and Delft3D Simulation Data of the Ganjiang Delta, China

Abstract Digitate shallow-water deltas are commonly found in modern lakes and bays, as well within cratonic petroliferous basins. They develop one or multiple sinuous finger-like sands (i.e., bar fingers), including high-RSI (sinuosity ratio of distributary channel finger ≥1) low-RSI (RSI < 1) types. Bar fingers consist four types subenvironments, that is, channels, point bars, mouth levees. However, the internal architecture above subenvironments is still unclear. This paper documents a digitate delta based on integration shallow-core ground-penetrating radar data from Ganjiang Delta, China, coupled with Delft3D simulations. Our results show convex-up muddy-silty accretion beds developed which top lap side channels bars down bottom bar. The have low dip angles (<2°), slightly higher for upper beds. Point unique to finger, inclined silty drapes, cohesive levee backwater effect impede migration channel, resulting drapes high-dip (can be >10°) compared those supplying river. angle exhibits negative relationship downstream distance positive exponential lateral distance. Silty become dense along direction channel. develops horizontal muddy large number (>3) high angles, thick levees, finger. this provide insights into prediction development reservoirs.