Clay Mineral Formation
Clay is that size fraction of the soil that consists of particles of less than 2 μm equivalent spherical diameter. The minerals that usually predominate in the clay fraction are termed clay minerals or phyllosilicates (see Clay minerals: silicates). Clay minerals are hydrous silicates or aluminosilicates, generally secondary, and they commonly form in nature by the alteration or weathering of primary minerals or by crystallization from solutions. The occurrence of clay minerals in soils is due to one of the following three major processes: inheritance, transformation or neoformation.
New techniques of analysis in the last 20 years, especially transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X‐ray microanalysis (EDS) have shown clay mineral formation in considerable detail (Banfield and Eggleton, 1990; Robert and Tessier, 1992; Banfield and Barker, 1994).
Clay minerals that form part of the parent materials of soils are passed...
- Banfield, J.L., Barker, W., 1994. Direct observation of reactant‐product interfaces formed in natural weathering of exsolved, defective amphibole to smectite: Evidence for episodic, isovolumetric reactions involving structural inheritance. Geochim. Cosmochim. Acta, 58: 1419–1429.CrossRefGoogle Scholar
- Barnhisel, R.I., and Bertsch, P.M., 1989. Chlorites and hydroxy‐interlayered vermiculite and smectite. In Dixon, J.B., and Weed, S.B., eds., Minerals in Soil Environments. Madison, WI: Soil Science Society of America, pp. 729–788.Google Scholar
- Barshad, J., 1966. The effect of a variation of precipitation on the nature of clay mineral formation in soils from acid and basic igneous rocks. Proc. Int. Clay Conf. (Jerusalem), 1: 167–173.Google Scholar
- Hsu, P.H., 1989. Aluminum oxides and oxyhydroxides. In Dixon, J.B., and Weed, S.B., eds., Minerals in Soil Environments. Madison, WI: Soil Science Society of America, pp. 331–378.Google Scholar
- Jackson, M.L., 1968. Weathering of primary and secondary minerals in soils. Trans. 9th Int. Congr. Soil Sci., 4: 281–292.Google Scholar
- Keller, W.D., 1970. Environmental aspects of clay minerals. J. Sediment. Petrol., 40: 788–813.Google Scholar
- Langmuir, D., 1997. Aqueous Environmental Geochemistry. Upper Saddle River, NJ: Prentice-Hall, 600 pp.Google Scholar
- Lindsay, W.L., 2001. Chemical Equilibria in Soils. Caldwell, NJ: Blackburn Press, 449 pp.Google Scholar
- Millot, G., 1964. Geologie des Argiles, Alterations, Sedimentologie, Geochimie. Paris: Masson, 499 pp.Google Scholar
- Norrish, K., 1972. Factors in the weathering of mica to vermiculite. Proc. Int. Clay Conf. (Madrid), 1: 417–432.Google Scholar
- Singer, A., and Norrish, K., 1974. Pedogenic palygorskite occurrences in Australia. Am. Mineral., 59: 508–517.Google Scholar
- Tazaki, K., and Fyfe, W.S., 1987. Formation of primitive clay precursors on K‐feldspar under extreme leaching conditions. Proc. Int. Clay Conf. (Denver), 53–58.Google Scholar
- Velbel, M.A., 1983. A dissolution‐reprecipitation mechanism for the pseudomorphous replacement plagioclase feldspar by clay minerals during weathering. Sci. Geol. Mem., 71: 139–147.Google Scholar
- Weaver, C.E., 1989. Clays, Muds and Shales. Amsterdam: Elsevier, 819 pp.Google Scholar
- Yaalon, D.H., Nathan, Y., Koyumdjisky, H., and Dan, J., 1966. Weathering and catenary differentiation of clay minerals in soils on various parent materials in Israel. Proc. Int. Clay Conf. (Jerusalem), 1: 187–198.Google Scholar