Past glacial extents in Nilosyrtis Mensae, Mars: Insights from successive moraine-like ridges and crater chronology

Abstract

Recent technological advancements have put Mars in the forefront of planetary interest, with several new missions planned. The Martian climate differs from Earths, lower surface gravity gives rise to steeper mountains and features, difference in sediment transport and different erosional patterns. There is also a clear dichotomy which divides the flat plane northern hemisphere from the rugged, crater-rich and volcano ridden southern-highlands. This study produced a geomorphological map of a valley within the Nilosyrtis region, which is at the meeting point of the dichotomy. The purpose was to identify glacier-like landforms, get an approximate age between the dichotomy and to investigate the surroundings. By using THEMIS, CTX and HiRISE data it was possible to see the extent of the lobate structure which originated from the valley and associate it with an approximate age that fell in the late Amazonian. With information of Mars obliquity and known glaciations during this period, it is possible to link the observed lobate structure to glacial activity. The valley is made up of several tributary valleys with visible VFF, LVF and ripples. There are also remnants from possible niche and cirque glaciers which when viewed in conjunction with the lobate structure could signify a piedmont glacier which has flown out into the open planes of the lowlands. Within the lobate various ridges are visible, boulderfield-like features, ripples and pitted terrain. The distinctive patterns of the various ridges could indicate possible recessional moraine. Overall, the mapping shows that the dichotomy boundary at this specific valley in Nilosyrtis is very complex.