Reconstructing Glaciers on Mars

Abstract:

Mars’ mid-latitudes host a substantial volume of ice, equivalent to a ~1 - 2.5 m-thick global layer or the sum of Earth’s glaciers and ice caps outside of Antarctica and Greenland. These deposits are the remnants of what is believed to have been a once far larger ‘ice age’, culminating in a last martian glacial maximum. Despite the identification of >1,300 glacier-like forms (GLFs) - the first order component of Mars’ glacial landsystem - in Mars’ mid-latitudes, little is known about their composition, dynamics or former extent. Here, we reconstruct the former 3D extent of a well-studied GLF located in eastern Hellas Planitia. We combine high-resolution geomorphic and topographic data, obtained from the High-Resolution Imaging Science Experiment (HiRISE) camera, to reconstruct the GLF’s former limits. We then apply a perfect plasticity rheological model, to generate multiple flow-parallel ice-surface transects. These are combined with the GLF’s boundary to guide interpolation using ArcGIS’ ‘Topo to Raster’ function to produce a continuous 3D surface for the reconstructed former GLF. Our results indicate that, since its reconstructed ‘recent maximum’ extent, the GLF’s volume has reduced by 0.31 km³ and its area by 6.85 km², or 70%. On-going research is addressing the degree to which this change is typical of Mars’ full GLF population.