Unfrozen brine in cryopegs

On Earth, chilled but unfrozen brine in rocky permafrost environments provides habitats for the growth of organisms and could provide habitats in similar conditions on Mars.

Cryopegs are isolated pockets of highly saline, liquid water that is permanently subzero (Celsius) in temperature due to chilling by the surrounding permafrost.

In this graphic, mm-cm refers to depths below the ground surface of millimeters to centimeters in vertical scale (fractions of an inch); cm-m refers to depths of centimeters to meters scale (half an inch to several yards); m-km refers to depths of meters to kilometers scale (a yard to a few miles); and 10's km refers to depth of tens of kilometers (several miles or more).