B. Székely1,2, T. Podobnikar1,3
1 Institute of Photogrammetry and Remote Sensing, Vienna University of Technology, Gusshausstr. 27-29, A-1040 Vienna, Austria
Telephone: (43) 1 58801-12251
Fax: (43) 1 58801-12299
2 Department of Geophysics and Space Science, Eötvös University, Budapest, H-1117 Budapest, Pázmány P. sétány 1/C, Hungary
Telephone: (36) 1 209-0555/6651
Fax: (36) 1 372-2927
3 Scientific Research Centre of the Slovenian Academy of Sciences and Arts, Novi trg 2, SI-1000 Ljubljana, Slovenia
Telephone: (386) 1-470-6493
Fax: (386) 1-425-7795
Terrestrial talus (or scree) slopes are common features in mountainous environments. Their geomorphic form is determined by their constituting material, scree or similar loose, often poorly sorted material. The angle of repose of this type of material defines more or less the surface slope of these forms. On Earth they are sometimes slightly vegetated, therefore they might become slightly oversteepened and metastable. Martian talus slopes are governed by differing environmental conditions: lower gravity (ca. 38% of the terrestrial), largely available loose material (often windblown), the lack of (present) fluvial erosion and typical large escarpments make the talus slopes more important areomorphic feature on Mars than on Earth. Our previous approach to outline terrestrial talus surfaces in the Eastern Alps in an automated way (Székely and Podobnikar 2008) has been successful in finding certain types of talus surfaces. On the other hand the method has been found to be somewhat sensitive to the resolution of the applied DTM. Here we apply a similar technique to two Martian DTMs derived from High Resolution Stereo Camera (HRSC) imagery on board of ESA Mars Express (Jaumann et al. 2007).
Our main aim is to separate and outline the talus surface areas from other slopes (like escarpments, impact rims, etc.) in the study areas of Nanedi Valles and West Candor Chasma in order to analyse the spatial distribution of this phenomenon, in craters, along escarpments, and, especially, in the area of vallis sides.