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Authors
Affiliations
1 Geological Survey of India, Bangalore-560 011, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 3 (1994), Pagination: 267-279
Abstract
The paper records the first occurrence of Orbicular rocks from the Closepet Granitoid belt near Hoskote, Tumkur district, Karnataka. The orbicules occur in a dioritic country rock enclosed within grey Closepet Granitoid. These are multishelled orbicules with shells of plagioclase and hornblende with a core of the same minerals. There are also proto-orbicules. The chemical analyses of orbicules fall in mafic tonalite field on K2O - CaO plots. Individual shells reflect a basic rock parentage. The orbicules are derived from a metabasic enclave due to granitic action by melting, diffusion and concretionary process in hydrous stage.
Keywords
Closepet Granites, Orbicules, Igneous Petrology, Hoskote, Tumkur, Karnataka.
