c © Author(s) 2009 Origin of proposed Rock–Glacier Landforms in Valles Marineris

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Valles; Thermokarst
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.601.333; http://elib.dlr.de/62263/1/Van_Gasselt.VM_Landslide.EPSC2009-473.pdf

many The Valles Marineris canyon system exhibits a variety of different landforms associated with landslide mech-anisms, ranging from several tens of meters to kilome-ters in length. They usually cover a surface of 1000 km2 and have an average volume of up to 5000 km3 (1; 2). It is assumed that they have been emplaced under either wet or dry conditions from destabilized wall–rock and from surrounding sapping valleys (e.g., 3; 1; 2; 4). Absolute age determinations performed by crater– size frequency distribution measurements on a variety of image data have furthermore shown that landslides in Valles Marineris span much of Martian history with ages as young as 50 Myr up to 3.5 Gyr (1). Notwith-standing their individual ages and time–span during which they have been emplaced, landslides seem to have formed repetitively producing comparable mor-phologies and do not show substantial modifications throughout the last 3.5 Gy (1). We here put our focus on a set of complex tongue-shaped landforms situated in the central parts of Valles Marineris at 283◦E, 8◦S which were previously identi-fied as a single feature and for which a possible rock– glacier origin has been proposed (5). This assump-tion implies environmental conditions which are not met today at such latitudes near the equator and which would contradict all observations related to the distri-bution of periglacial landforms on Mars, such as ther-mal contraction polygons, thermokarst features, and –