Weathering of micas

Wang TSC, Li SW (1977) Clay minerals as heterogeneous catalysts in preparation of model humic substances. Z Pfanzenemaehr Bodenkd 140 669-676 Weed SB, Dave CB, Cook MG (1969) Weathering of micas by fungi. Soil Sci Soc... 

Illite clays may result from the weathering of micas and feldspars. Their formation in soils and sediments is favored by high K" " and moderate silica concentrations. When smectites or mixed-layer smectite/illite clays are buried in deep sedimentary basins, they are gradually transformed into more stable illites by a combination of time and temperature (diagenesis) (cf. Velde and Vasseur 1992 Huang et al. 1993 Cuadros and Linares 1996). The reaction involved might be... 

In the accelerated laboratory weathering of mica, Na tetraphenylboron is an extremely effective reagent because it reacts with released K+ to form the insoluble K tetraphenylboron precipitate, thereby maintaining a very low concentration of ions in solution. 

Norrish K (1973) Factors in the weathering of mica to vermicnlite. 5th Int l Clay Conf Proc, Madrid, p 417-432... 

Leyval, C., Laheurte, R, Belgy, G., Berthehn, 1., 1990. Weathering of micas in the rhizospheres of maize, pine and beech seedlings influenced by mycorrhizal and bacterial inoculation. Symbiosis 9, 105-109. 

Background. We have become particularly interested in the weathering of micas in soils. This weathering process is geochemically and environmentally important because it is a major source of potassium in the soil system (and therefore of paramount importance to plants), and the weathering products typically include other sheet silicates with high cation exchange capacities (CEC). These secondary minerals play an important role in the mobility of toxic metals and nutrients in soils. 

Kunze, G. W. (1952). Weathering of micas and their role in potash fixation. Ph.D. Thesis, Pennsylvania State College. 

An increasing proportion of vermiculite in interstratified mica-vermiculite in the upper horizons of the arable and forested soils due to weathering of mica by loss of interlayer potassium. 

In contrast to the homogeneous mica distribution in weakly podzolised sod-podzolic soils, higher illite contents and accumulation of expansible minerals have been found in a medium podzolised sod-podzolic soil by Labenets [1968]. In strongly podzolised acid soils, weathering of micas, especially of biotites, produces mixed-layered minerals, vermiculite, and soil mont-morillonite. These processes lead to a decrease of illite contents in the upper parts of the... 

Norrish, K., 1972. Factors in the weathering of mica to vermiculite. Preprints, Int. Clay Conf. Madrid. Vol. II, pp. 83-101. 

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