Amazonian mid- to high-latitude glaciation on Mars: Supply-limited ice sources, ice accumulation patterns, and concentric crater fill glacial flow and ice sequestration

Cross-sectional sketches illustrating thin versus thick regional ice cover. (a) Change in climate in mid-high latitudes produces conditions conducive to the accumulation of snow and ice and a thin regional snow/ice layer accumulates, preferentially on crater walls (top). Steep wall slopes cause glacial ice to start to flow inward, and debris is shed from the steep wall slope to the ice surface, adding to the development of a sublimation till (bottom). Climate change causes loss of regional snow and ice, and the thicker flowing glacial ice is preserved under a protective sublimation till. (b) Alternatively, global climate change causes emplacement of a very thick (many hundreds of meters) regional snow and ice layer that flows into the crater interior, filling it to the brim (top). Climate change then causes loss of the regional snow/ice sheet (bottom), exposing the walls and adding wall debris to the cover of the flowing glacial ice, enhancing its preservation. 79.