Post by Dr. Stephen Brough, School of Geography, Politics and Sociology, Newcastle University, UK.
There exist thousands of putative debris-covered glaciers in the mid-latitudes of Mars (e.g. Souness et al., 2012; Levy et al., 2014). Much like their terrestrial counterparts, many of these glaciers have undergone mass loss and recession since a former glacial maximum stand (e.g. Kargel et al., 1995; Dickson et al, 2008) (Image 1). However, there is a lack of knowledge regarding the volume of ice lost since that time and whether such recession has been spatially variable. Reconstructing glacial environments based on their landforms and structural assemblage is a powerful concept applied in terrestrial glaciology. Through utilising evidence left on the landscape with observations from modern glaciers, it is possible to reconstruct the extent and dynamics of both former (glaciated) and modern (glacierised) glacial environments (see Bennett and Glasser, 2009). This month’s planetary geomorphology post investigates how similar techniques have been utilised to reconstruct the former extent of glaciers on our planetary neighbour, Mars.
Image 1: Glacier recession on Earth and Mars. (a – b) Location of martian glacier in the Phlegra Montes region of Mars’ northern hemisphere (~164.48 oE, ~34.13 oN). Background is MOLA elevation overlain on THEMIS-IR daytime image. (c) Near terminus Context Camera (CTX) image expansion of Phlegra Montes martian glacier. White arrows indicate arcuate ridges in glacier forefield that occupies the southern half of image. Subset of CTX image P16_007368_2152_XN_35N195W. (d) The forefield of terrestrial Midre Lovénbreen, Svalbard, is shown for comparison. White arrows indicate arcuate terminal moraine indicating the glacier’s former expanded extent. Modified from Hubbard et al., 2014.
