Exploring the Martian subsurface of Athabasca using MARSIS radar data: Testing the volcanic and fluvial hypotheses for the origin of the morphology

This work aims to test the formation hypotheses of the rafted-plate morphology observed in the Martian area of Athabasca Valles (5degN, 150degE,) using the subsurface radar echo from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) 5 MHz-band data over this area. The backscattered signal losses are compared to those arising from two geoelectrical subsurface models (differing in their assumed ice content) generated by finite-difference time-domain (FDTD) simulations. Within this region, the MARSIS signal experience average losses of 0.09 dB/m in the first 160 m beneath the surface. FDTD simulations suggests that, if the near-surface environment is ice-rich (80% by volume), it will result in average losses of 0.048 dB/m, whereas the losses associated with an ice-poor model (20% of ice by volume) increase to 0.10dB/m. Comparing the observed MARSIS losses with the simulated ones suggests that the propagation characteristics of Athabasca´s subsurface are more consistent with a volcanic rather than a fluvial origin for the rafted-plate terrain.