Origin of the ice of the Latitude Dependent Mantle (LDM) revealed by ice-exposing scarps on Mars

We present a global survey of 232 ice-exposing scarps incised into the Latitude Dependent Mantle (LDM) on Mars and analyze their morphology, spatial distribution, and geomorphological context. These features are confined to 40–60°latitude due to the latitudinal dependence of sublimation-driven scarp formation and the equatorward extent of excess subsurface ice. Scarps are predominantly located on the lower, concave parts of leeward hillslopes, suggesting these areas represent zones of preferential snow accumulation and preservation. Using high-resolution digital terrain models, we estimated the local thickness of the Latitude-Dependent Mantle (LDM) from the depth of scarp depressions. Values range from 40 to over 190 meters, with thicker mantles observed downslope and on leeward slopes. The morphology and internal stratigraphy of the exposed layers reveal variable geometries, including fine, dipping layering interpreted as wind-blown snow mixed with dust and sand, similar to terrestrial niveo-aeolian deposits. These results support the hypothesis that the LDM formed through atmospheric processes, with wind and topography jointly controlling the distribution, structure, and thickness of ice-rich deposits. This has implications for Amazonian climate interpretations, as the LDM may not preserve a continuous climate record, and for future in situ resource utilization (ISRU), where ice accessibility is likely to vary greatly at small scales depending on local terrain and past depositional conditions. • Ice-exposing scarps preferentially form on the lower parts of leeward hillslopes, suggesting the ice that hosts them accumulated as wind-driven snow. • The thickness of the ice that hosts scarps is highly variable, ranging from 40 to more than 190 meters, and depends on local topography and potentially paleo wind direction. • Scarp setting and exposed layers support an atmospheric origin for the LDM, with implications for both climate interpretation and future ice resource accessibility on Mars.