A geocryological account of the Schirmacher Oasis

Abstract

Abstract The Schirmacher Oasis is a small, ice‐free area, some 18 km by 1.8 km, located in Dronning Maud Land and lying between the Lazarev Ice Shelf to the north and the Antarctic Ice Cap to the south. The climate is quite variable with a mean annual air temperature of ‐10°C, a mean temperature of ‐18.1°C for the coldest month and ‐0.7°C for the warmest month. Annual precipitation is approximately 300 mm. The entire area is underlain by permafrost. Active layer depths range between 80 cm in dry, fine‐grained materials and 7 cm in areas of ice‐rich algal accumulations. The author investigated in detail the depth of the active layer in a stony polygon. In unconsolidated materials the commonest variant of cryogenic structure is a massive subtype with no lenses or layers of ice; a streaky subtype occurs in some fine‐grained sediments. Segregation ice is relatively rare and no wedge ice was reported. The only massive ground ice is buried glacier ice near the ice cap margin. Frost shattering is the most widespread and most effective weathering mechanism. Sorted circles, nets and polygons are widespread in the unconsolidated materials and were studied in detail by the author. Sorted stripes occur only rarely. Thermokarst is very poorly developed even where blocks of buried ice were exposed.