Colours on this map of Mars’ “Heart Lake” and its surrounds in the northern Arabia Terra region, snapped by the Context Camera and High Resolution Imaging Science Experiment camera on NASA’s Mars Reconnaissance Orbiter, shows lower elevations in white and purple and higher elevations in yellow.
In the Journal of Geophysical Research, Planets, US researchers examined such maps and data and found lakes and snowmelt-fed streams on Mars formed roughly a billion years after a well-documented, earlier era of wet conditions on ancient Mars – much later than previously thought possible.
This suggests surface conditions at this later time may also have been suitable for microbial life.