Soils of MacRobertson Land

Abstract

MacRobertson Land is the portion of Antarctica lying south of the Mawson Coast between 59° 34′ E and 72° 35′ E. At 5,400 km2, MacRobertson Land constitutes the third largest ice-free area in Antarctica, accounting for 11 % of the total ice-free area. Less than 10 % of the ice area occurs along the coast. It has five major ice-free areas: (i) the Northern Prince Charles Mountains, including the Amery Oasis, (ii) the Southern Prince Charles Mountains, including the Mawson Escarpment, (iii) the Grove Mountains, (iv) a series of small coastal oases and inland Framnes Mountains along the Mawson Coast, and (v) the Vestfold Hills, Rauer-Bolingen Islands, and Larsemann Hills along the Ingrid Christensen Coast. Elevation differences of over 3,000 m and distances of ice-free areas from the coast up to 650 km inland create sharp contrasts in climatic conditions and have a marked impact on pedogenesis. Permafrost is continuous in MacRobertson Land. Active-layer depths range from 25 cm in the Grove Mountains to 110 cm or more on the coast. Patterned ground is ubiquitous in the areas with frost-susceptible parent materials throughout the region. Soil-forming processes can be examined along an elevational-longitudinal gradient from the Vestfold-Larsemann Hills to the southern Prince Charles and Grove Mountains. Salinization, manifested in salt efflorescence, carbonation, and permafrost development are expected to increase from the coast inland; pervection, and soil organic matter accumulation are greatest along the coast. Desert pavement formation and rubification are important processes along the entire gradient. Unlike Wilkes Land and South Shetland Islands, podzolization has not been reported in MacRobertson Land. The dominant soil taxa along the coast are Aquiturbels, Haploturbels, previously unclassified ornithogenic and limnogenic soils, and endo- and epi-lithic soil-like bodies. Lithic Anhyorthels are predominant in the inland mountains.