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Lamellar structure in orthopyroxenes (With Plate IV)

Published online by Cambridge University Press:  14 March 2018

N. F. M. Henry
N. F. M. Henry*
Affiliation:
Department of Mineralogy and Petrology, University of Cambridge
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Extract

The fine lamellar structure (pl. IV, fig. 1 a and b) which is described here is very common in the orthopyroxenes of plutonic and regionally metamorphosed rocks. This structure can be seen under crossed nicols in sections inclined at a high angle to the optic axial plane (100), except on those sections which make a low angle with (001). When the main part of the crystal is in extinction, the fine lamellae stand out because their extinction position is different from that of the main crystal. Although this structure is common, it is not described in any of the widely used text-books, but several descriptions and references to it have been published in recent years. The purpose of this paper is to draw attention to the nature of this lamellar structure.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 26 , Issue 176 , March 1942 , pp. 179 - 189
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1942

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