Hypsometric analysis of Margaritifer Sinus and origin of valley networks

[1] The formation of Martian valley networks has been debated since their discovery. The relative roles of groundwater sapping and fluvial runoff processes have different implications onMartian paleoclimate. This paper uses a hypsometric analysis technique that has been tested on terrestrial landforms to analyze the hypsometric attributes of watershed basins in theMargaritifer Sinus region onMars usingMars Orbiter Laser Altimeter (MOLA) gridded topographic data. On the basis of quantitative characteristics of their hypsometric attributes, the majority of the basins (covering 3/5 of the study area) look more like terrestrial basins of sapping origin, and a significant number of basins (covering 1/5 of the study area) are more fluvial like. The classification of the rest of the basin is less certain at the presently available resolution of the digital elevation model (DEM). Overlay with Viking photomosaic indicates that the classification is generally consistent with the morphology shown in Viking images. Although this analysis alone cannot make a sure determination of valley network origin, combined with other morphometric analysis, the results from this study are consistent with a valley network formation by precipitation-recharged groundwater sapping, suggesting a warm and wet climate for early Mars.