Groundwater Sapping and Valley Formation on Mars

Drainage basins and channel incision on Mars

“…Photometric and stereo techniques were used to derive local topography (12,16,17) but lacked precise slope information. However, recent measurements made by the Mars Orbiter Laser Altimeter (7) on board the Mars Global Surveyor (18) allow construction of a digital elevation model (DEM) from topographic profiles of typical vertical accuracy ϳ1 m, interpolated on a grid with spatial resolution 1 ϫ 1 km.…”

“…Knowledge of the topography permits extension of such analyses by using additional quantitative criteria. Longitudinal stream profiles, locations of channels relative to surface topography, and transverse cross sections of valleys (12,13) may now be used to constrain the genesis and evolution of Martian valleys.…”

Paleohydrology of Eberswalde crater, Mars

“…This discrepancy between empirical and theoretical results has motivated investigations of higher-thanexpected solar luminosity, obliquity variations, more effective greenhouse gases, carbon dioxide clouds, albedo differences, and release of volatiles by impacts or volcanism as possible ways of warming the planet (e.g., Baker et al, 1991;Whitmire et al, 1995;Sagan and Chyba, 1997;Segura et al, 2002;Colaprete and Toon, 2003;Segura et al, 2008Segura et al, , 2012Mischna et al, 2013;Ramirez et al, 2014). Other investigators have examined ways to erode valleys under cold conditions, including ice flow, stream flow under an ice cover, or generation of meltwater by surface (impact ejecta) or subsurface (geothermal) heat sources (e.g., Wallace and Sagan, 1979;Carr, 1983;Brakenridge et al, 1985;Wilhelms and Baldwin, 1989;Brakenridge, 1990;Gulick and Baker, 1990;Carr, 1995;Goldspiel and Squyres, 2000;Harrison and Grimm, 2002;Carr and Head, 2003;Mangold et al, 2012a). Quantitative constraints on the Martian paleoclimate based on landform morphometry would have considerable value in guiding these modeling efforts.…”

Quantifying geological processes on Mars—Results of the high resolution stereo camera (HRSC) on Mars express

“…The current view is that these fluvial valley networks have been formed by a variety of erosive processes by liquid water, including fluvial erosion exclusively (e.g., Malin and Carr, 1999;Malin and Edgett, 2000a), groundwater sapping exclusively resulting from geothermal or hydrothermal heating (e.g., Sharp and Malin, 1975;Pieri, 1976Pieri, , 1980Howard, 1988;Squyres, 1989;Baker, 1990;Gulick, 1998;Goldspiel and Squyres, 2000;Gulick, 2001;Luo, 2002) and a combination of surface runoff and groundwater sapping (e.g., Milton, 1973;Baker and Kochel, 1979;Baker, 1989, 1990;Baker et al, 1992;Carr, 1995Carr, , 1996aGrant, 2000;Malin and Edgett, 2000a). In this context, HRSC data provided new items for formation processes in relation with a potential water cycle on Mars.…”