Exsolution in Metamorphic Bytownite

  • T. L. Grove

Abstract

It is not possible to investigate the exsolution in calcic plagioclases using synthetic materials and standard phase equilibria experiments. The kinetics of the exchange NaSi⇌CaAl involved in the unmixing are slow, and cannot be reproduced on a laboratory time scale. Therefore, to characterize the compositional limits and crystallographic relations of coexisting calcic plagioclases, it is necessary to examine natural plagioclases from a variety of environments. To date, TEM studies of exsolution in bytownites and labradorites have been carried out on samples from both igneous and metamorphic rocks. In an attempt to expand our knowledge of the miscibility gap this study of plagioclases formed in a metamorphic environment was undertaken.

Keywords

Petrol 

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© Springer-Verlag Berlin · Heidelberg 1976

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  • T. L. Grove

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