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Recent basal melting of a mid-latitude glacier on Mars

Butcher, Frances E. G.; Balme, M. R.; Gallagher, C.; Arnold, N. S.; Conway, S. J.; Hagermann, A. and Lewis, S. R. (2017). Recent basal melting of a mid-latitude glacier on Mars. Journal of Geophysical Research: Planets, 122(12) pp. 2445–2468.

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DOI (Digital Object Identifier) Link: https://doi.org/10.1002/2017je005434
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Abstract

Evidence for past basal melting of young (late Amazonian), debris-covered glaciers in Mars’ mid-latitudes is extremely rare. Thus, it is widely thought that these viscous flow features (VFFs) have been perennially frozen to their beds. We identify an instance of recent, localized wet-based mid-latitude glaciation, evidenced by a candidate esker emerging from a VFF in a tectonic rift in Tempe Terra. Eskers are sedimentary ridges deposited in ice-walled meltwater conduits and are indicative of glacial melting. We compare the candidate esker to terrestrial analogues, present a geomorphic map of landforms in the rift, and develop a landsystem model to explain their formation. We propose that the candidate esker formed during a transient phase of wet-based glaciation. We then consider the similarity between the geologic setting of the new candidate esker and that of the only other candidate esker to be identified in association with an existing mid-latitude VFF; both are within tectonic graben/rifts proximal to volcanic provinces. Finally, we calculate potential basal temperatures for a range of VFF thicknesses, driving stresses, mean annual surface temperatures, and geothermal heat fluxes, which unlike previous studies, include the possible role of internal strain heating. Strain heating can form an important additional heat source, especially in flow convergence zones, or where ice is warmer due to elevated surface temperatures or geothermal heat flux. Elevated geothermal heat flux within rifts, perhaps combined with locally-elevated strain heating, may have permitted wet-based glaciation during the late Amazonian, when cold climates precluded more extensive wet-based glaciation on Mars.

Item Type: Journal Item
Copyright Holders: 2017 American Geophysical Union
ISSN: 2169-9100
Keywords: Mars; glacier; esker; meltwater; wet-based glaciation; geothermal
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Space
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Item ID: 52438
Depositing User: Frances Butcher
Date Deposited: 28 Nov 2017 15:12
Last Modified: 23 May 2018 08:50
URI: http://oro.open.ac.uk/id/eprint/52438
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