McMurdo Dry Valleys, Antarctica

Cryptoendolithic ( "hidden" within rock) microbial communities

These communities consist of melanized fungi, partnered with free living photosynthetic algae or cyanobacteria, as well as lichenized partners; resulting in characteristic coloured banding that occurs mm's below the surface of the rock. 

Dry Valley Permafrost 
The McMurdo Dry Valleys uniquely have the presence of both ice-cemented permafrost, and dry permafrost - soil that remains below 0C year round, but that contains negligible water content, so that mineral particles are not bound together by ice. University Valley, is a high Elevation Dry Valley that has the presence of dry permafrost overlaying ice-cemented permafrost, and is thus a great analog for the dry permafrost that exists in the polar regions of Mars. 

Dry Permafrost that doesn't have sufficient water to freeze mineral particles together. 

Like Mars, the permafrost terrain has landscape scale polygonal structures. In the Arctic, the troughs are underlain by ice wedges, while the Dry Valleys may have sand wedges instead. 

In situ gas flux measurements on polygonal terrain.