Soil Genesis Associated with Periglacial Ice Wedge Casts, Southcentral Wyoming1
- L. C. Munn2
The development of ice and sand wedges (nonsorted polygon features) in Wyoming's high basins during the late-Pleistocene glaciation allows determination of soil development on pre-Wisconsin and late-Wisconsin surfaces on the same landform. Pre-Wisconsin soils on an old alluvial terrace in the Great Divide Basin (later hosts to ice wedges) exhibited clay translocation and accumulation followed by a period during which carbonate accumulated. Soils developed in the noncalcareous fill-materials of the ice-wedge casts show B horizon accumulation of clay and carbonate. The late-Wisconsin soils developed in the ice wedge casts showed clay enrichment of 13 kg m−2 and CaCO3 enrichment of 113 kg m−2. The pre-Wisconsin soil had CaCO3 enrichment of 250 kg m−2. Parent material stratification prevented determination of absolute clay enrichment in the host soil but its clay maximum is 33% compared to 15% in the late-Wisconsin soil. The Bt horizons in the pre-Wisconsin soils are also much thicker. Profile morphology indicates that the present semi-arid environment probably developed immediately as the climate warmed at the end of the Wisconsin. Clay mica and kaolinite have become enriched in surface horizons and smectite in C horizons of both wedge and wedge-host soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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