Signs of the most recent life on Mars may have sprung up from underground. Because they would have been protected from harsh conditions on the surface, such as radiation, pockets of underground water may be where Martian life existed most recently.
Sulphates, made through interaction with briny water, lie all over Mars. As water underground is also briny, this suggested frequent upwellings.
But Joseph Michalski of the Planetary Science Institute in Tucson, Arizona, and colleagues found that most basins, where groundwater would have pooled, are free of sulphates. The deep McLaughlin crater is instead rich in clays and carbonates which also formed through contact with water.
A better question would be "Does Mars hide life in its watery pockets?" To read more, click here.