HIGH ALTITUDE ICE-RICH DEPOSITS ON MARS: COMPARING HECATES THOLUS AND ALBA PATERA

Hecates Tholus (centered at 32. °N, 150 °E), Mars, is a volcano in the northern Elysium region with a basal diameter of ~180 km and a peak elevation of 4.8 km. The presence of water ice on Hecates Tholus has previously been inferred both in putative rock glaciers in a depression on its northwestern flank and as a source of water for radial channels on its slopes. However, there has been little investigation into the presence of ice near the summit. Context Camera (CTX) and High-Resolution Imaging Science Experiment (HiRISE) images show a deposit characterized by decameter-scale hills within the summit caldera complex, predominantly on north-facing slopes near the southern caldera walls (centered at 31.64°N, 150.10°E). Previous work identified similar deposits in Alba Patera (40°N, 250°E). Preliminary investigations suggest that the deposits on Hecates Tholus resemble the “hummocky” textures previously identified in Alba Patera, but the “smooth” texture, interpreted to be small lobate debris aprons, is not observed in Hecates Tholus. Deposits at both locations are interpreted to be ice-rich, and formed as ice-rich material was preferentially deposited or preserved due to reduced insolation on north-facing slopes. Further examination of the features on Hecates Tholus will use Mars Orbiter Laser Altimeter (MOLA) elevation data alongside CTX and HiRISE images.