Distribution, classification, and ages of martian impact crater lakes

Paleolakes in impact craters on Mars are characterized at global scale using the Viking Orbiter data. We identified 179 paleolakes in impact structures formed by the influx of water and sediment derived from valley networks and channels that can be classified into three different fluviolacustrine systems: closed, open, and lake-chain systems. We show the hydrogeologic implications for each of the three systems and their significance in terms of duration of fluviolacustrine activity. This study provides a catalog of areographic, physical, and physiographic data for each of the studied impact crater lakes, associated with the description of the sedimentary structures observed. It also identifies environments where life and/or precursors to life could have found favorable conditions to evolve. (C) 1999 Academic Press.