Soil distribution in the McMurdo Dry Valleys, Antarctica

The McMurdo Dry Valleys (MDVs) are the largest ice-free area (ca. 6692 km2) in Antarctica. Here we present a reconnaissance (scale = 1:2 million) soil map of the MDVs. The soil map units are subgroups as identified in the U.S. Department of Agriculture Soil Taxonomy. The dominant soil subgroups in the MDVs are Typic Anhyorthels (43%), Typic Haploturbels (36%), and Typic Anhyturbels (14%). Soils of the MDVs represent an evolutionary sequence that include Glacic Haploturbels/Anhyturbels on Holocene surfaces, Typic Haploturbels/Anhyturbels on late Quaternary surfaces, Typic Anhyorthels on late to mid-Quaternary surfaces, Salic Anhyorthels on mid-to early Quaternary surfaces, and Petrosalic/Petrogypsic/Petronitric Anhyorthels on Pliocene and older surfaces. Soils on silt-rich tills of Pliocene and older age generally are Typic or Salic Anhyorthels; they feature less weathering than younger soils because (i) they are derived from quartzose materials largely devoid of weatherable minerals and (ii) they have been subject to considerable wind erosion.