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HiRISE observations of gas sublimation-driven activity in Mars’ southern polar regions: III. Models of processes involving translucent ice |
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| Authors: | Ganna Portyankina Wojciech J Markiewicz Candice J Hansen |
| Institution: | a Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland b Max-Planck Institute for Solar System Research, Max-Planck Strasse 2, D-37191 Katlenburg-Lindau, Germany c Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA d United States Geological Survey, 2255 North Gemini Drive, Flagstaff, AZ 86001, USA |
| Abstract: | Enigmatic surface features, known as ‘spiders’, found at high southern martian latitudes, are probably caused by sublimation-driven erosion under the seasonal carbon dioxide ice cap. The Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) has imaged this terrain in unprecedented details throughout southern spring. It has been postulated Kieffer, H.H., Titus, T.N., Mullins, K.F., Christensen, P.R., 2000. J. Geophys. Res. 105, 9653-9700] that translucent CO2 slab ice traps gas sublimating at the ice surface boundary. Wherever the pressure is released the escaping gas jet entrains loose surface material and carries it to the top of the ice where it is carried downslope and/or downwind and deposited in a fan shape. Here we model two stages of this scenario: first, the cleaning of CO2 slab ice from dust, and then, the breaking of the slab ice plate under the pressure built below it by subliming ice. Our modeling results and analysis of HiRISE images support the gas jet hypothesis and show that outbursts happen very early in spring. |
| Keywords: | Mars Mars Polar caps Ices Mars Surface |
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