Harmakhis Vallis Source Region, Mars: Insights into the recent geothermal history based on geological mapping

The mapped area of Harmakhis Vallis, at the eastern Hellas Planitia region(35130–421500S; 91100– 971300E), covers the surface area of about 212,000 km2. Theregiondisplaysanenhancedmodificationof the initial topography formed by the Hellas impact. The long and complex history of degradationand alteration involves mass-wasting processes, volcanism and fluvial activity, confronting effects of climate-induced slow mass-wasting processes to effects caused by temporary, catastrophic events (impact cratering, volcanism,etc.). Geological mapping at scale of 1:1,500,000 (full scale at 1:540,000) have been carried out on multiple co-registered datasets available from the past and ongoing orbiter missions to Mars. The mapped geomorphic features of small- and medium-scales reveal in detail events that shaped the topography of the region throughout history, providing specific constraints on the geologic and climatic history of the region. This study highlights events from the most recent Martian history, including fluvial activity recorded in relation to a debris apron flanking Centauri Montes, and evidence of recent positive geothermal anomalies of a high heat-flux with relatively small spatial extents, on the time scale of several million years ago.