Radar Attenuation Characteristics of Low Reflectivity Zones in the Martian South Polar Layered Deposits

Abstract

Both sets of Martian polar layered deposits (PLDs) display semi‐rhythmic reflector stratigraphy in radargrams. The southern PLDs (SPLD), among other peculiarities, also contain widespread, distinctive deposits with few to no reflections that commonly occur at or near the top of the stratigraphic column. Here, we study the low reflectivity zones (LRZs) to determine whether they exhibit radar properties indicative of non‐water ice. We find that the previously reported CO2‐ice LRZ exhibits a distinct radar signature compared to all other LRZs. We also found behavior that suggests that the other LRZs may contribute to increased radar signal attenuation, which does not support a CO2 ice composition. We observe many instances of LRZs comprising the entire SPLD column and find that the radar attenuation varies across different LRZs, suggesting unique properties within each of these deposits. Variable radar attenuation of LRZs may be connected to differences in bulk compositions, radar‐sensitive roughness characteristics, and/or distributions of stratigraphic materials.