Origin and evolution of the outflow channels on Mars using HRSC 3-D imaging

Giant erosional valleys on the surface of Mars, termed outflow channels, are testament to massive amounts of erosion of the Martian crust. These valleys are widely believed to have been carved by the catastrophic release of groundwater, which initiated cataclysmic floods that caused large-scale erosion. The morphology of these valleys can be used to infer constraints on the depth of floodwaters, water flow velocities and discharges. However, deriving these values requires detailed topographic data. We aim to map the morphology of the outflow channels using stereo camera (HRSC) Mars Express imagery and derived 3D information. We will look for evidence of flood stage indicators in the Martian landscape, so that we can accurately determine the heights that flood event/s attained. To do this we will use photointerpretation and geological mapping, based on automated topographical measurements, morphometric analysis and remote age determination, to produce a geological and hydrological history of key examples of outflow channels. Three dimensional models of the Martian surface will be automatically derived from the HRSC images, using a refinement of existing stereo processing software systems. These 3D models and the associated images, co-registered with data from previous US missions, will be used to map and quantify geomorphic features associated with the outflow channels. Automated crater detection algorithms (developed under existing PPARC support) will be applied to derive ages of surface units and constrain a time-stratigraphic sequence of climatic and geological events. We will use these results to compute estimates of flow velocities and water discharges associated with flood events. This information will provide important clues to understanding the evolution of water on Mars and has implications for discovering the presence or past presence of alien life. This work will form part of the scientific output from the High Resolution Stereo Camera operations phase of the ESA Mars Express mission.