DEBRIS SOURCES AND SURFACE EVOLUTION AT EMMONS GLACIER, MOUNT RAINIER IN RELATION TO POSSIBLE LANDSLIDE DEPOSITS ON MARTIAN VISCOUS FLOW FEATURES

Mass wasting events such as landslides occur on Earth and Mars. Landslides can cover glaciers with debris, which can armor the underlying glacier ice from melting. Across the mid-latitudes of Mars, there are buried ice deposits that have been interpreted as possible debris-covered glaciers. In particular, Martian glacier-like forms (GLFs) and Lobate Debris Aprons (LDAs) are stagnant in the current climate but were dynamic in the past and we do not fully understand the co-evolution of debris and ice on Mars. Previous studies have mapped GLFs and LDAs and evaluated their morphologies using high-resolution imagery, topography, and radar. Previous studies have also investigated landslide deposits on Mars. While the mapped mid-latitude flow features and mapped landslide deposits overlap in only very few locations, we use high-resolution imagery and topography to evaluate surface morphology and structure in these locations. This evaluation is informed by our work on the debris-covered Emmons Glacier on Mount Rainier in Washington, USA. In 1963, Emmons Glacier experienced a landslide that covered most of the lower glacier. In this field study, we use high-resolution satellite imagery to map the landslide deposit covering the glacier. We conducted sedimentological analyses to better identify transport paths that landslide and glaciogenic debris has taken since deposition on Emmons Glacier. Field measurements of clast size and angularity were determined via orthogonal axes and using Power Roundness scale, respectively, and have been collected at over 30 sample sites across the debris cover from 2019 to 2022. The surface morphology, debris characteristics, and sediment transport of Emmons Glacier provides a case study in the evolution of a debris-covered glacier following a landslide event. Our on-the-ground analyses of Emmons Glacier deepens our understanding compared to using satellite imagery alone. This terrestrial understanding will be considered in relation to how we may interpret the surface morphologies and surface structures of any locations where mapped landslide deposits may be coincident with mapped GLFs or LDAs on Mars.