HiPOD: Boulders in Gully Alcoves

Gullies are often found on steep slopes. In the winter, this area is covered with a layer of carbon dioxide ice (dry ice). In the spring, when the ice warms up and transitions to gas, it dislodges material on the slope, forming a gully.

In general, this process works best on fine material, leaving behind large boulders. These boulders can be seen collected in the gully alcoves.

https://uahirise.org/hipod/ESP_039747_1090
NASA/JPL-Caltech/UArizona
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