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An Occurrence of Authigenic Nacrite

Published online by Cambridge University Press:  02 April 2024

D. Bühmann
D. Bühmann*
Affiliation:
Department of Geology and Mineralogy, University of Natal, Pietermaritzburg, Republic of South Africa
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Abstract

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Euhedral, pseudohexagonal nacrite was discovered as a thin layer coating a carbonaceous shale in the Sherwood Tunnel in Durban, Republic of South Africa. The nacrite apparently formed authigenically within a few weeks at ambient temperature by precipitation from pore solutions, probably as a result of evaporation. This observation suggests that nacrite can no longer be considered to indicate a high-temperature genetic environment. Precipitation from saturated pore solution may have been the mechanism of formation for this kaolin-mineral polymorph.

Keywords

AuthigenesisKaolin-group mineralNacritePore solutionShale
Type
Research Article
Information
Clays and Clay Minerals , Volume 36 , Issue 2 , April 1988 , pp. 137 - 140
Copyright
Copyright © 1988, The Clay Minerals Society

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