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Notes on the Petrology and Mineralogy of the Barrovian Metamorphic Zones

Published online by Cambridge University Press:  01 May 2009

N. J. Snelling
N. J. Snelling
Affiliation:
Research School of Physical Sciences, Australian National University, Canberra, A.C.T.
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Abstract

The antipathetic relation between chloritoid and biotite in the lower metamorphic grades of the Barrovian zones and the genesis of the index minerals in the higher metamorphic grades are briefly discussed. The observed mineral assemblages of 13 new analyses of peltic schists are compared with the assemblage required by the mineralogical phase rule; good agreement exists provided allowance is made for magnesia acting as a separate component. Six new biotite analyses covering all of the Barrovian zones show an increase in the degree of replacement of Si**** by Al*** with increase in metamorphic grade. The ratio of FeO: MgO varies according to the associated ferromagnesian minerals and shows no regular relation to metamorphic grade.

Type
Articles
Information
Geological Magazine , Volume 94 , Issue 4 , August 1957 , pp. 297 - 304
Copyright
Copyright © Cambridge University Press 1957

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References

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