Recent tectonics and subsidence on Mars: Hints from Aureum Chaos

High spatial and spectral resolution imagery and topography collected during the last decade are changing our vision of Mars into that of a geologically active planet, even in recent times. However, the connection between internal activity such as faulting and other recent geomorphic processes and deposits, such as eolian or mass wasting units, is difficult to establish. In this work we study a geomorphic feature located inside Aureum Chaos (4 degrees S, 333 degrees E) which is situated at the dichotomy boundary between southern highlands and northern lowlands on Mars. We identified fault-related activity based on HIRISE imagery and mapped a landslide of LTD (Light Tone Deposits) material which seems to be modified by a fault. Displacement measurements across the scarp are in agreement with values measured in other Amazonian-aged extensional settings on Mars. Moreover, the relation between landslide and eolian material shows that it was produced very recently in time, since the activity seems to postdate a dune field whose age was determined to be less than 1.9 Myr old. This observation together with other scarp-related activity near the area suggests that very recent subsidence activity has occurred along previous fault planes inside Aureum Chaos. (C) 2011 Elsevier B.V. All rights reserved.