The evolution of lacustrine environments on Mars: Is Mars only hydrologically dormant?

This study surveys the evolution of martian impact crater paleolakes throug h time by establishing their age, comparing their locations, and describing the formation of lacustrine sedimentary structures and features over time. We explore their meaning in terms of global climate changes, but also on l ocal and regional scales. We observe a co-location between recent impact cr ater paleolakes and regions where GCM modeling shows that Mars is currently experiencing days above triple point and below boiling point of water. Som e source areas show morphologies that could be consistent with ancient glac ier features in the Argyre Basin/Darwin Crater region, in locations that ar e also consistent with GCM models of past snow precipitation on Mars. We pr opose that, at least for some paleolakes, our results are best explained by recent, and abundant, aqueous activity on Mars, with some meteorological c ontribution. These results are supported by other recent findings on martia n meteorite ages, by the analysis of new MGS data showing recent volcanic a nd fluvial activity, and by climate modeling. They point toward the possibi lity that Mars currently is only hydrologically dormant and that there is a potential for hydrological activity to be generated again in the future fo llowing changes in the planet's orbital parameters. (C) 2001 Academic Press .