Boulder Pavement (77.5227°S, 161.7466°E) is an area ca 1.5 hour hike from the Lake Vanda along the Onyx River. It is the most extensive area of microbial mats in the Wright Valley. When I visited the area it was still too early in the season to have water running or much growth of microbial mats.
However, i was able to find one spot where the ice had melted and bright orange microbial mats were visible. The orange colour is due to carotenoids, pigments that protect the cyanobacterial cells from UV radiation and reactive oxygen species.
Orange-pigmented cyanobacteria-dominated mats
Dried river bed near Boulder Pavement