Avulsion dynamics determine fluvial fan morphology in a cellular model

Abstract Fluvial fans are large, low-gradient depositional systems that occur in sedimentary basins worldwide. can represent much of the geologic record foreland basins, create hazards, and paleoclimate tectonic signals. However, we lack an understanding how fluvial grow into variety shapes observed around world. We explored this aspect using a cellular model basin landscape evolution with rules for sediment transport, river avulsion, floodplain processes. tested hypothesis avulsion dynamics, namely, trigger period abandoned channel primary control on fan development. found shorter periods lead to rounder planform because, between avulsions, aggradation (and thus setup) propagates distances from upstream boundary along pathways. This prioritizes lateral dispersion, creating shorter, fans, over delivery further basin, which would elongated fans. Modeled attraction (but not repulsion) generated commonly abrupt marked by transition distributary tributary patterns. While thought be linked climate, they anywhere rivers aggrade, lose confinement, preserve alluvial topography. Instead, might more recognizable environments frequently avulsions channels capture future avulsions.