Soil Development and Glacial History, West Fork of Beaver Creek, Uinta Mountains, Utah

Abstract

ABSTRACT The dominant mechanisms of soil formation on a sequence of Smiths Fork, Blacks Fork, and Pre–Blacks Fork moraines in West Fork of Beaver Creek, Uinta Mountains, Utah, (equivalent to Pinedale, Bull Lake, and Pre–Bull Lake moraines of the Wind River Range, respectively) are clay translocation (argilluviation), increasing soil redness (rubification), and the accumulation of organic matter (melanization) and silt-sized particles. The quantity of clay-sized particles and degree of soil redness increase with soil age, but clay accumulation may plateau in the oldest soils. In contrast, the quantity of accumulated organic matter and abundance of silt-sized particles do not appear to correlate to soil age. The Smiths Fork moraine, interpreted to be MIS-2 in age, has two crests that have distinctly different amounts of clast weathering and soil development. The outer Smiths Fork crest displays weathering that is more comparable to that of the Blacks Fork moraine than to the inner Smiths Fork crest. This weathering contrast is related to an age difference between the two crests, but a precise chronology of the Smiths Fork moraines cannot be determined from these data.