Journal ArticleDOI
The Experimental Transformation of Mica toward Smectite*; Relative Importance of Total Charge and Tetrahedral Substitution
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In this paper, the influence of crystal-chemical composition on the ease of transformation of micas to vermiculite or more smectite-like minerals is emphasized, and the swelling test, with glycerol, of Mg-saturated mineral is used to characterize the degree of transformation.Abstract:
This article emphasizes the influence of crystal-chemical composition on the ease of transformation of micas to vermiculite or more smectite-like minerals. The swelling test, with glycerol, of Mg-saturated mineral is used to characterize the degree of transformation. The main structural factors of this evolution are tetrahedral substitution of Si by Al, and total charge. There is a relation between these two factors, i.e. the lower the tetrahedral substitution, the greater can be the charge without affecting the smectite swelling behavior. In this respect there is a contrast between tri and dioctahedral micas. In the first, tetrahedral Al is so high (> 1·20 for Si4O10) that transformation into smectite must imply modification of the tetrahedral layer. For dioctahedral micaceous phyllites (illites, glauconites) where tetrahedral charge is lower, transformation can be easier. Only a lowering of total charge is needed and reduction-oxidation seems to play a very important role in this process.read more
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Kinetics of muscovite, phlogopite, and biotite dissolution and alteration at pH 1-4, room temperature
TL;DR: In this article, the reaction kinetics of dioctahedral muscovite and trio-chedral phlogopite and biotite were studied in aqueous solutions at pH 1-4 and room temperature.
Journal ArticleDOI
Nature of mixed-layer clays and mechanisms of their formation and alteration
TL;DR: In this article, mixed-layer clays are intermediate products of reactions involving pure end-member clays and they come from natural environments ranging from surface to low-grade metamorphic and hydrothermal conditions Most often mixed layering is essentially two component.
Journal ArticleDOI
A new data set of soil mineralogy for dust-cycle modeling
Emilie Journet,Emilie Journet,Yves Balkanski,Sandy P. Harrison,Sandy P. Harrison,Sandy P. Harrison +5 more
TL;DR: In this paper, the authors present a data set that characterizes the clay and silt-sized fractions of global soil units in terms of the abundance of 12 minerals that are important for dust-climate interactions: quartz, feldspars, illite, smectite, kaolinite, chlorite, vermiculite, mica, calcite, gypsum, hematite and goethite.
Journal ArticleDOI
A review on palaeogeographic implications and temporal variation in glaucony composition
TL;DR: In this paper, a review on palaeogeographic implications and temporal variations of glaucony covering both modern and ancient records is presented, which is related to the abundance of the most common substrates, faecal pellets and bioclasts.
Journal ArticleDOI
Mineralogy and genesis of smectites in an alkaline-saline environment of pantanal wetland, brazil
Sheila Aparecida Correia Furquim,Robert C. Graham,Laurent Barbiero,José Pereira de Queiroz Neto,Vincent Valles +4 more
TL;DR: In this paper, the authors investigated the mineralogy of smectites in the soils surrounding a representative alkaline-saline lake of Nhecolândia, a subregion of the Pantanal wetland, Brazil, and then to identify the mechanisms of their formation.
References
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Journal Article
The mineralogy of illites and mixed-layer illite/montmorillonites
John Hower,Thomas C. Mowatt +1 more
Journal ArticleDOI
Lithium and potassium absorption, dehydroxylation temperature, and structural water content of aluminous smectites*
TL;DR: In this article, the Greene-Kelly Li+-test was used to distinguish between the ideal and non-ideal types of beidellite, and a distinction between Wyoming, Tatatilla, Otay, and Chambers was made between the two types.