Characteristics and Genesis of Some Soils of the Upper Terraces of Lake Bonneville

Abstract

The genesis and characteristics of the Timpanogos, Hillfield, and Sterling soils and an unnamed Mollisol (soil formed on north- slope) on the east part of Cache Valley were studied in order to determine (1) why the soil morphology is not chronologically related to the geomorphic surface and (2} why different soils have developed on these surfaces , even though the soil forming factors appear similar. The particle size distribution of the upper horizons of the Timpanogos, Hillfield , and unnamed Mollisol pedons are relatively similar . These soils developed from stratified deposits with granulimetric composition in which 75 to 90 percent of the grains are less than 100 micrometers in diameter , characteristic of wind-blown material. Development of an incipient argillic horizon in Timpanogos pedon indicates this soil did not develop under the moist conditions of the Pleistocene and the geomorphic surface was not stable after deposition. The material was reworked by the wind. The Sterling soil formed on an alluvial fan which was deposited during Holocene time and its development is chronologically related to geomorphic surface. The development of an incipient argillic horizon in the Timpanogos soil and a weak cambic horizon in the Hillfield soil and the unnamed Mollisol is due to topographic condition of the landscapes. The thick and dark mollie epipedon in the unnamed Mollisol (north-slope) compared to the Hillfield soil (south- s lope) which has an epipedon with color light to be mollie and a less thick A horizon is related to effect of microclimate

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