Date of Award:

1-1-1980

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Advisor/Chair:

Jerome J. Jurinak

Abstract

The mineralogy and morphology of a soil with a cambic horizon (Stingal) and a soil with an argillic horizon (Hansel), occurring in northern Utah, were studied. Pedons representing the central concept of each of the soils were sampled by genetic horizon for laboratory analyses. Particle- size distribution, calcium carbonate equivalent, cation-exchange capacity, organic carbon , and the mineralogy of the silt, coarse clay, and fine clay fractions were determined. Thin sections of the soils were examined with a petrographic microscope. Selected peds were observed using a scanning electron microscope, and elemental analyses were made with an x-ray analyzer.

The two soils were found to be similar in many respects . The particle-size distribution and mineralogy were essentially the same, indicating the similarities of parent materials and the nature of pedogenic processes. As expected, the argillic horizon contained more.

fine and total clay than did the cambic horizon, and the Hansel soil showed signs of more intense weathering. Both factors are related to the greater age of the Hansel soils.

The clay increase in both the cambic and the argillic horizons was attributed to a combination of ill situ clay formation and illuviation. This conclusion was based on the lack of depositional discontinuities, greater ratios of fine to total clay in the B horizons, and the electron microscopic observation of discontinuous clay films in pores of the Hansel soil. The lack of visible clay films in thin section is probably the result of soil mixing by cicada and/or the prevention of translocation by carbonates.

The scanning electron microscope proved to be useful in the investigation of the two soils. The similarities of the two soils were apparent from laboratory analyses and scanning microscope observations. Evidence of illuviation, which was lacking in thin section, was visible with the scanning electron microscope, thus demonstrating the potential of the microscope in classifying and interpreting soils in future investigations.

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