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Why are clay minerals small?

Alain Meunier
Why are clay minerals small?
Clay Minerals (June 2006) 41 (2): 551-566


The most abundant silicates formed under the Earth's "normal" surface conditions, i.e. clay minerals, are always of small grain size. Under the same conditions, other mineral species such as carbonates, sulphates and oxides may form much bigger crystals. The reason why phyllosilicates formed in soils or in weathered rocks are always of small grain size is not related to the low-temperature-pressure conditions but rather to particular aspects of their crystal structure. Many recently published works describe the order-disorder cation distribution in the tetrahedral and octahedral sheets and the crystal defects in the layer stacks. Related to the Periodic Bond Chains (PBCs) theory, these data suggest that the size and the shape of clay crystallites could depend on the amount of crystal defects in the three axes of symmetry [100], [110] and [110]. The accumulation of crystal defects poisons the crystal growth along one, two or three PBCs. Then, nucleation becomes less energy-consuming than crystal growth and favours the formation of numerous smaller crystals rather than fewer bigger ones.

ISSN: 0009-8558
EISSN: 1471-8030
Serial Title: Clay Minerals
Serial Volume: 41
Serial Issue: 2
Title: Why are clay minerals small?
Author(s): Meunier, Alain
Affiliation: Universite de Poitiers, HYDRASA, Poitiers, France
Pages: 551-566
Published: 200606
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 48
Accession Number: 2006-081583
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200646
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