Soil Genesis Associated with Periglacial Ice Wedge Casts, Southcentral Wyoming
1987
Munn, L. C.
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.
显示更多 [+] 显示较少 [-]