Evidence for an ancient ‘Lake Gusev’ on Mars has come and gone several times. That lake is looking pretty good today, thanks to new research. New research suggests floodwaters entered the crater through the huge valley that breaches Gusev’s southern rim. These floods appear to have ponded long enough to alter the tephra, producing briny solutions. When the brines evaporated, they left behind residues of carbonate minerals. As the lake filled and dried, perhaps many times in succession, it loaded Comanche and its neighbor rocks with carbonates.
from Space & Time News — ScienceDaily http://ift.tt/1krSoU4