Weathering of Montmorillonite During Formation of a Solodic Soil II. Nature of the Mixed Layer Products
1969
Klages, M. G.
The Solodic (Paleargid) soil being studied had previously been shown to have clay mineralogy similar to that of associated Chestnut (Argiustol) and Solodized-Solonetz (Natrargid) soils. Mica and montmorillonite were the dominant clay minerals in the calcareous glacial till parent material. Montmorillonite failed to give an X-ray diffraction peak in clays of the surface soil, yet infrared absorption, cation exchange capacity, and surface area were similar to that of the parent material. Clays of the parent material (C horizon) and surface soil (A horizon) were studied to determine mineralogical properties. Dioctahedral and trioctahedral minerals were present in both the A and C horizon with dioctahedral predominating. Quantitative estimates of mineral composition were made on the basis of infrared absorption, total potassium, and cation exchange properties. These showed kaolinite, quartz, chlorite, vermiculite, and allophane to be present in addition to mica and montmorillonite. Differences in clay mineral content from the parent material to the surface soil were minor. It was concluded that the most important effect of soil formation on clay mineralogy was a change from relatively pure mineral crystals to particles with several 2:1 minerals in a highly random arrangement of various degrees of interlayer expansion.
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