Carbon dioxide glaciers control the location of the Martian South Polar Residual Cap

I. B. Smith, N.-J. Schlegel, E. Larour, I. Isola, P. Buhler, N. E. Putzig and R. Greve


The south polar residual cap (SPRC) of Mars is a unit of carbon dioxide ice up to ten meters thick that caps a thicker massive carbon dioxide ice deposit (MCID) and the south polar layered deposits (SPLD). The location of the SPRC has been an enigma since the earliest observations of Mars, because it resides in a unique position offset from the south pole, only partially covering the highest elevations of the polar cap. We employ geologic mapping and the three dimensional Ice-sheet and Sea-level System Model (ISSM) to show that the position of the SPRC is co-incident with and driven by glacial flow of the MCID into topographic basins. Our results indicate that glacial processes create the unique conditions necessary to preserve the SPRC in its current location and explains the discontinuous distribution of CO2 ice. Our work represents the strongest evidence of carbon dioxide glaciation on Mars to date.

Nature Geoscience (submitted).

Last modified: 2021-01-11