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The Occurrence of Orthoclase and Microcline in the Granitic Gneisses of the Carn Chuinneag-Inchbae Complex, E. Ross-shire

Published online by Cambridge University Press:  01 May 2009

R. I. Harker
R. I. Harker
Affiliation:
Mineral Sciences Building, Pennsylvania State College, Pennsylvania, U.S.A.
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Abstract

Optical examination of the potash feldspars in the granitic gneisses of the Carn Chuinneag-Inchbae complex suggests that both ortho-clase and microcline occur together—not infrequently in the same crystal. Optic axial and extinction angles, intermediate in value between those characteristic of the two polymorphs, have been recorded and plotted graphically. X-ray powder diffraction patterns confirm that both orthoclase and microcline are present together in these rocks. It is believed that most of the microcline developed from orthoclase during the regional metamorphism of the area, which permitted recrystallization at a lower temperature than that at which the orthoclase was formed.

Type
Articles
Information
Geological Magazine , Volume 91 , Issue 2 , April 1954 , pp. 129 - 136
Copyright
Copyright © Cambridge University Press 1954

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