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Stacking defects and long-period polytypes in kaolin minerals from a hydrothermal deposit

Toshihiro Kogure and Atsuyuki Inoue
Stacking defects and long-period polytypes in kaolin minerals from a hydrothermal deposit
European Journal of Mineralogy (June 2005) 17 (3): 465-473

Abstract

Stacking defects in kaolin minerals (mainly dickite) from a hydrothermal deposit (a high-sulphidation type of Au deposit at Kasuga mine, Kagoshima Prefecture, Japan) have been characterized by HRTEM with sufficient image quality to determine the defect structures. A comprehensive correspondence between the stacking sequences for kaolin polytypes belonging to sub-family A and their HRTEM contrasts recorded along the hexagonal a (sub 1) axes is described. Both disorder of the layer orientations (equivalent to octahedral vacancy sites) and that of the directions for interlayer shift were observed. The probability of forming the stacking sequence in which the direction of the interlayer shift and layer orientation in the lower or upper layer are the same is very low, but not zero. Long-period polytypic sequences with three- and five-layer periodicities were found. One MDO polytype in the trigonal system with three-layer periodicity was discovered among them. Such long-period polytypes in kaolin minerals are explained by spiral growth with a multilayered edge, as in micas.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 17
Serial Issue: 3
Title: Stacking defects and long-period polytypes in kaolin minerals from a hydrothermal deposit
Affiliation: University of Tokyo, Department of Earth and Planetary Sciences, Tokyo, Japan
Pages: 465-473
Published: 200506
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 29
Accession Number: 2005-044760
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: Chiba University, JPN, Japan
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200526
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