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Evolution of the granulites and sub-division of the granulite facies in Ceylon

Published online by Cambridge University Press:  01 May 2009

D. J. A. C. Hapuarachchi
Affiliation:
Geological Survey Department, Colombo 2, Ceylon

Summary

Three subfacies of the granulite facies are recognized: garnet–diopside–quartz subfacies; pyroxene–granulite subfacies; and hornblende–granulite subfacies The erection of a garnet–diopside–quartz subfacies follows De Waard's suggestion (1965) of a garnet–clinopyroxene subfacies. Two major divisions of the hornblende–granulite subfacies are now recognized, (i) garnet–biotite division, (ii) cordierite division. Three sub-divisions of the former are suggested on the basis of critical basic assemblages. Since wollastonite has been found to have a limited areal occurrence within the latter, a two-fold sub-division of the cordierite division is suggested on the basis of the assemblages, (a) calcite–quartz, (b) wollastonite. A seven-fold sub-division of the granulite facies is thus proposed for Ceylon rocks. An attempt is made to trace briefly the major events in the metamorphic history of the rocks supported by available geochronological evidence.

Type
Articles
Copyright
Copyright © Cambridge University Press 1972

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