Distribution and Morphology of Alluvial Fans and Deltas in Gale Crater, Mars: An Integrated Multi-Source Remote-Sensing Analysis

Alluvial fans and deltas in Gale crater preserve important records of sediment transport from crater-rim and wall catchments to depositional environments on the crater floor. This study investigates their spatial distribution, morphology, source-to-sink relationships, surface texture, and volume using an integrated orbital remote-sensing framework. Deposit boundaries and channel remnants were mapped from the 5 m/pixel Context Camera (CTX) global mosaic, while elevation, slope, drainage networks, catchment boundaries, and volume estimates were derived from the 200 m MOLA–HRSC blended digital elevation model. A total of 12 alluvial fans and three deltas were identified. Most deposits are concentrated along the northwestern crater margin, whereas the southern crater floor is dominated by a broad, low-gradient fan. Comparisons among representative systems show that catchment area alone cannot explain preserved deposit size; sediment-routing efficiency, topographic confinement, accommodation space, depositional setting, and post-depositional modification are also important controls. Volume estimates differ substantially between planar basal-surface fitting and parallel-profile reconstruction, indicating strong method dependence. These results provide a consistent basis for comparing Gale crater depositional systems and demonstrate that preserved fan and delta morphology reflects combined source, transport, depositional, and preservation processes.