Porphyritic Plagioclase-Hornblende-Pyroxene Granulite from Charnockitic Rocks of Chipurupalli, Visakhapatnam District, Andhra Pradesh, South India

K. S. R. Rao, A. T. Rao and A. Sriramadas
Department of Geology, Andhra University, Waltair, India

Summary: An unusual occurrence of porphyritic plagioclase-hornblende-pyroxene granulite (porphyritic basic charnockite) has been observed within the ‘Charnockite region’ of the Eastern Ghats of the Precambrian formations of India. From the X-ray and chemical data the phenocrysts are considered to be augite phenocrysts. Based on petrographic and chemical evidence it is inferred that the basic charnockites of Chipurupalli area in Visakhapatnam district are formed from tholeiitic magma as a gabbroic mass under deep seated plutonic conditions. The gabbroic mass has been recrystallized as plagioclase-hornblende-pyroxene granulite due to later metamorphism, leaving most of the phenocrysts unaffected.

Mineralogical Magazine; December 1969 v. 37; no. 288; p. 497-503; DOI: 10.1180/minmag.1969.037.288.10
© 1969, The Mineralogical Society
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