Permafrost distribution in the southern circumpolar region and its relation to the environment: A review and recommendations for further research

Because of basal melting beneath the massive Antarctic ice sheet, permafrost probably comprises less than 25% of the Southern Circumpolar Region ( c . ≥ 50°S latitude). Permafrost is pervasive in ice‐free areas of Antarctica and its offshore islands but is lacking in the sub‐Antarctic islands, except possibly at the higher elevations. Based on limited data, the thickness of permafrost ranges from 100 to 1000m in ice‐free areas of Antarctica. The thickness of the active layer ranges between 50 and 150 cm in the Antarctic islands and maritime East Antarctica and 15 and 50 cm in interior Antarctica. Ground ice is restricted to rock glaciers and ice wedges; the rock glaciers, palsa and thermokarst reported in some areas originate from ice‐cored drift and not permafrost. Active and inactive patterned ground occurs throughout the region. Whereas sorted circles, nets, and stripes are common in the Antarctic islands and in maritime East Antarctica, ice‐ and sand‐wedge polygons are prevalent in ice‐free valleys of Antarctica. Altiplanation terraces may exist in the Antarctic islands and in maritime East Antarctica; however, landforms in interior Antarctica are controlled more by salt weathering than by cryogenic processes. Based‐on the presence of inactive rock glaciers, gelifluction lobes, and large‐scale patterned‐ground features, permafrost was probably present in the sub‐Antarctic islands during the last glaciation. Recommendations are made for future work in the region.