Fine-grained Micas in Soils

Reichenbach, H. Graf von; Rich, C. I.

doi:10.1007/978-3-642-65917-1_3

Cited by 21 publications

(13 citation statements)

References 109 publications

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“…Only few studies have reported illite in soils and weathered rocks as being a product of neoformation (e.g., after a primary frame silicate). Among reported cases of illite neoformation under meteoric conditions, the reaction is predominantly thought to be driven by the alteration of K-feldspar (Reichenbach and Rich, 1975;Meunier, 1980;Singer, 1989;Meunier and Velde, 2004). Only two studies known to us have mentioned that plagioclase feldspar could also be involved in illite neoformation (Bourgeon, 1992;Jiménez-Espinosa et al, 2007).…”

Section: Introductionmentioning

confidence: 96%

Illite neoformation in plagioclase during weathering: Evidence from semi-arid Northeast Brazil

et al. 2009

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Section: Introductionmentioning

confidence: 96%

Illite neoformation in plagioclase during weathering: Evidence from semi-arid Northeast Brazil

et al. 2009

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“…Biotite in soils is considered to be an important source of potassium and minor elements for plants, and a large number of workers have been prompted to investigate the morphological, mineralogical, and chemical features affecting the release of ions from biotite during synthetic weathering (see recent reviews by Reichenbach and Rich, 1975;Fanning and Keramidas, 1977). In laboratory experiments biotite alters to vermiculite or mixed-layer clay minerals, whereas the products of natural weathering may also be kaolinite, halloysite, illite, smectite, chlorite, and sesquioxides.…”

Section: Introductionmentioning

confidence: 99%

Biotite Alteration in Deeply Weathered Granite. I. Morphological, Mineralogical, and Chemical Properties

Gilkes

Suddhiprakarn

1979

Clays and clay miner.

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Abstract--Biotite in deeply weathered granitic rocks in southwestern Australia has altered to exfoliated grains composed of biotite, mixed-layer clay minerals, kaolinite, vermiculite, gibbsite, goethite, and hematite. Discrete vermiculite and vermiculite-dominant mixed-layer clay minerals are not major weathering products. Oxidation of octahedrai iron in biotite is associated with ejection of octahedrai cations, loss of interlayer K, and a contraction of the b-dimension of the biotite sheet. Si, Mg, Ca, Mn, K, and Na are lost from biotite during weathering, and Ti, Al, Ni, and Cr are retained. Fe and water have been added to the grains during weathering. Much Fe occurs as aggregates of microcystailine, aluminum-rich goethite particles on flake surfaces and within etchpits, with smaller amounts occurring as hexagonal arrangements of lath-shaped crystals of goethite on flake surfaces.

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“…Studies of both artificial and natural weathering of micas have been reviewed by Norrish (1973), von Reichenbach and Rich (1975), and Fanning and Kerimidas (1977). Most of the earlier work dealt with relatively large (-1 mm) specimens which, because of their size, could be isolated from accompanying material, examined optically and analyzed directly by various macroscopic methods (Walker, 1949;Wilson, 1970;Farmer et aL, 1971;and Rimsaite, 1975).…”

Section: Introductionmentioning

confidence: 99%

Treatment of Microanalyses of Intimately Mixed Products of Mica Weathering

Fordham

1990

Clays and clay miner.

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Abstract-Weathering of minerals often produces intimate mixtures of reactants and products in a smaller volume than that explored by an electron microprobe. As a result, many microanalyses are difficult to decipher because they are composite analyses of mixtures. A procedure to resolve such microanalyses into their component parts was applied here to data obtained in a study of the weathering of muscovite and biotite in granite gneiss and associated soils. A key element oxide content (K20, in the examples demonstrated) was plotted against Si/A1 ratio for all data. This achieved a spread of points having an external shape depending on the compositions of the pure phases present in the various mixtures analyzed. In all probability, some of the microanalyses consisted of only a single phase, or almost so, and these points were located at or near extremities of the body of data. The aim of subsequent treatment was to encompass the data within boundary curves, each of which corresponded to mixtures of any two of the pure phases present. The chemical compositions of some phases, for example, kaolinite and muscovite, are known, and boundary curves for such mixtures were calculated directly. The compositions of unknown or suspected phases, however, were estimated from the graph of K20 content against Si/Al ratio, in conjunction with graphs of the other element oxide contents plotted against Si/A1 ratio. The unknown compositions were subsequently refined by successive approximations. Data in the vicinity of the boundary curves were adjusted for the presence of free iron oxides containing structural A1. Once a satisfactory set of intersecting boundary curves was developed to encompass the data, the compositions of the major phases in each system were obtained, and the diagram of boundary curves was used to estimate the relative proportions of these phases at each point analyzed by the microprobe.

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Fine-grained Micas in Soils

Cited by 21 publications

References 109 publications

Illite neoformation in plagioclase during weathering: Evidence from semi-arid Northeast Brazil

Illite neoformation in plagioclase during weathering: Evidence from semi-arid Northeast Brazil

Biotite Alteration in Deeply Weathered Granite. I. Morphological, Mineralogical, and Chemical Properties

Treatment of Microanalyses of Intimately Mixed Products of Mica Weathering

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