Journal ArticleDOI
A soil vermiculite formed from a meta-gabbro, Loire-Atlantique, France
P. Ildefonse,E. Copin,B. Velde +2 more
TLDR
In this paper, microprobe and atomic absorption analyses of large vermiculite crystals present in the upper horizon of a weathering profile on gabbro show that they differ appreciably in chemical composition.Abstract:
Microprobe and atomic absorption analyses of large vermiculite crystals present in the upper horizon of a weathering profile on gabbro show that they differ appreciably in chemical composition. This together with the lack of any phyllosilicate precursor of comparable grain size, strongly suggests that the vermiculites were formed by precipitation of dissolved silicate matter, higher in the profile the vermiculite becomes unstable and is replaced by an Fe-rich smectite.read more
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Journal ArticleDOI
Weathering of enstatite to talc through a sequence of transitional phases
TL;DR: In this paper, the authors describe the transformation of orthopyroxene to talc plus oxides through three sequential mineral reactions without the development of a non-crystalline phase.
Journal ArticleDOI
Metasomatic and non-metasomatic low grade metamorphism of Ordovician meta-bentonites in Sweden
Bruce Velde,A.M. Brusewitz +1 more
TL;DR: Bulk rock and electron microprobe analyses of two series of meta-bentonite beds one of which was subjected to low grade metamorphic conditions indicate that K is the most important element in the metasomatic transformation of volcanic ash into bentonite clay mineral assemblages as discussed by the authors.
Journal ArticleDOI
Clay minerals in early amphibole weathering : Tri- to dioctahedral sequence as a function of crystallization sites in the amphibole
TL;DR: The early stages of amphibole weathering result in the crystallization of several clay mineral species: tri-and dioctahedral smectites, interstratified dihedral kaolinite-smectite (K-S), and halloysite as mentioned in this paper.
Book ChapterDOI
Chapter 5 Stability Fields of Smectites and Illites Including Glauconites as a Function of Temperature and Chemical Composition
TL;DR: In this article, the authors deal with stability fields of smectites and illites including glauconites as a function of temperature and chemical composition, and show that these clay minerals form or survive over a wide range of temperature, pressure and solution concentration conditions.