Parent Material-Clay Relations in Some Northern Utah Soils1
- A. R. Southard and
- R. W. Miller2
It is frequently stated that soils with well-developed A and B horizons are sufficiently weathered that their clays will reflect strongly the influence of the climatic environment. Studies of three profiles developed from sedimentary rock materials in northern Utah show a high association between parent material, kind of clay in each parent material, and kind of clay in the soil derived from the rock materials.
Soil derived from a calcareous, red matrixed conglomerate (Wasatch) contains 20 to 50% of clay as kaolinite. Soil formed from a particular and distinctly calcareous tuffaceous deposit has dominantly montmorillonite clays, with no evidence of kaolinite even in horizons lying adjacent to soil layers developed from Wasatch conglomerate. Where a particular limestone is the main parent rock, the soil contains some kaolinite and montmorillonite, but the proportions of different clays are little changed at different depths. These data and other observations not reported here strongly support the concept that clays in soils of the northern Utah area developed since Pleistocene times or even longer are mostly a result of heredity, if the soils are derived from sedimentary parent rock. Climate is a subordinate factor in altering the kinds of clays found in these soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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