Some Characteristics of Clay Skins on Peds in the B Horizon of a Gray-Brown Podzolic Soil
1959
Buol, S. W. | Hole, F. D.
Clay coatings or skins were removed from peds in the B₃ horizon of a Gray-Brown Podzolic soil of southern Wisconsin. Analyses were made to determine the contents, both in the clay skins and in the entire horizon, of N, C, clay, reductant-soluble Fe, total Fe, Al, Na, K, Ca, Si, Mg, and Ti. Thin sections were made of peds from the B₃ horizon and were examined with the aid of a petrographic microscope to determine the structure of the clay skins. The results of analyses for the clay skins show relatively high contents of N (0.11%), C (1.836%), clay (87.4%), free Fe (2.76%), as compared with contents in the bulk sample from the B₃ horizon: 0.029% N, 0.417% C, 24.3% clay, and 1.33% free Fe. X-ray diffraction patterns showed that the clay in the bulk sample contained slightly more chlorite and slightly less vermiculite and chlorite-vermiculite intergrade than the clay of the clay skin. Microscopic thin-sections of clay skins showed a mean clay-skin thickness of 0.079 mm., with component lamellae each 0.007 to 0.010 mm. thick.
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