The northern ice cap of Mars: an enigmatic evolution compared to the polar environment on Earth

摘要

Would it be possible to interpret the dynamics of the northern polar ice cap of Mars with the same criteria as for terrestrial ice sheets? The aim of this paper is to illustrate the problems posed by such an approach. We present a detailed study of the MOC narrow angle image E01-01773, taken at 83.5°N/241.4°W in the upper part of a 300 km-long depression situated at the edge of the northern polar ice cap. On Mars, every depression resembling a valley is a "chasma", and as this one has no official name, we suggest to call it "West Olympia Chasma" (WOC). By analyzing the satellite image, we have been able to highlight some unusual features of martian glacial geomorphology and to compare them with topographies and sediments known in terrestrial glacial environments. In particular: