On an Anatectic Granite from Bygland, South Norway

R. Sen and Ananda Deb Mukherjee
Department of Geology, Presidency College, Calcutta
Department of Geological Sciences, Jadavpur University, Calcutta-32

Summary: The Pre-Cambrian granitic rocks of Bygland are structurally and texturally concordant with the metamorphosed country rocks. Both these rock types plot close together in Q-Or-Ab and Ab-An-Or normative diagrams; trace element distribution is also similar. The granite has been reconstituted from the country rocks under epidote-amphibolite facies conditions. Plagioclase feldspars show that the granite is not a ‘mature’ rock; they are, however, ‘mature’ in the country rocks and are products of typical regional metamorphism (Ohta et al, 1968). Plagioclases in the granite are relicts of country rocks showing traces of a premetamorphic crystalline state. They have been rejuvenated with the introduction of alkali material during the reconstitution.

Mineralogical Magazine; June 1973 v. 39; no. 302; p. 216-223; DOI: 10.1180/minmag.1973.039.302.09
© 1973, The Mineralogical Society
Mineralogical Society (www.minersoc.org)