Landslides and the Tectonic Scarp in Coprates Chasma -- Examples Studied from HRSC Data

Introduction: Coprates Chasma forms the eastern part of the Valles Marineris main trough. A striking feature of Coprates is the linear scarp at the floor joint, cutting spur and gully systems on the wall, thus leaving triangular facets. This scarp, especially prominent on the northern wall of Coprates Chasma, can be categorized as a tectonic faulting feature [1]. While the scarp is mostly intact throughout the Coprates system, major landslides stretching across the canyon floor were already found from VIKING images [2]. We looked at the new MEX-HRSC data to see evidence for smaller mass wasting events, too, in the 1 km range that would overlap the tectonic scarp. Hence, we would arrange a three level age estimation: events predating the scarp, events associated or contemporating with the scarp, and events postdating the scarp. Furthermore, the presence of a fan-shaped apron would indicate the landslide to be younger in age or more resistant to fluvial or aeolian erosional processes that took place on the canyon floor.