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 (35 degrees 30-42 degrees 50'S; 91 degrees 00-97 degrees 30'E), covers the surface area of about 212,000 km(2). The region displays an enhanced modification of the initial topography formed by the Hellas impact. The long and complex history of degradation and 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 data sets 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 timescale of several million years ago. (C) 2010 Elsevier Ltd. All rights reserved.