MGFR · The (missing) fingerprints of Martian large-scale glaciations

Thousands of valley networks incise the Martian southern hemisphere, evidence that liquid water sculpted the Martian surface billions of years ago. This scenario contrasts starkly with the much colder and drier planet that Mars is nowadays, with frozen water accumulated on the polar caps and hundreds of mid-latitude glacial deposits, all frozen to the ground. In transit between these two climate scenarios, liquid water stability regions would have shifted to warmer, high pressure regions, and water would have accumulated beneath the growing ice masses, providing a stable environment for possible ancient life forms. Geological evidence for this transient period, however, is notoriously missing on Mars. Whereas the motion of glacial masses lubricated by subglacial meltwater (wet-based) produces arresting landscapes showing extensive linear substrate scouring on Earth, similar large-scale linear features are missing on Mars, leading to the historical interpretation that Martian ice masses were always frozen to the ground. The project presented here aims to revisit this idea adapting the physical framework describing terrestrial glacial hydrology to Mars, to show that the lower Martian surface gravity affects the dynamics of wet-based glaciers by favoring the emplacement of efficient meltwater subglacial drainage conduits, limiting ice sliding velocity, and producing different erosional fingerprints. Using mathematical models, analogue experiments, and geomorphological comparisons between Martian and terrestrial landforms, my objective is to show that the fingerprints of wet-based glaciation on Mars may be fundamentally different from those on Earth, challenging the current view and raising the possibility of a period of water stability under ancient Martian ice sheets. This project will help guide the search for ancient environments on Mars where water would have been stable, and where life could have existed shielded from the surface for extended periods of time.