International Journal of Earth Sciences and Engineering

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Basalt-Andesite-Dacite-Rhyolite (BADR) Metavolcanic Sequence from the Central Part of Dharwar-Shimoga Greenstone Belt, Western Dharwar Craton


Affiliations
1 Department of Studies in Geology, Karnatak University, Dharwad-580003, India
2 Department of Geology, Central University of Kerala, Kasaragod-671123, India
 

The petrographic and major element geochemical characteristics clearly suggest that the metavolcanic rocks of Medur Formation in the central part of the Dharwar-Shimoga greenstone belt comprise basalt, andesite, dacite and rhyolite (BADR) sequence. These metavolcanic rocks are metamorphosed to greenschist-amphibolite facies. The basalts show mixed tholeiitic and komatiitic composition. The andesites are mainly tholeiitic, while dacite and rhyolites are calc alkaline nature. Good correlation exists between SiO2 and major oxides, which suggests that these metavolcanic series (BADR) compositions are genetically inter-related and were derived probably from differentiation of magma at different depths.

Keywords

Metavolcanics, Petrography, Geochemistry, Dharwar-Shimoga Greenstone Belt, Dharwar Craton.
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  • Basalt-Andesite-Dacite-Rhyolite (BADR) Metavolcanic Sequence from the Central Part of Dharwar-Shimoga Greenstone Belt, Western Dharwar Craton

Abstract Views: 157  |  PDF Views: 119

Authors

T. B. Manuvachari
Department of Studies in Geology, Karnatak University, Dharwad-580003, India
A. G. Ugarkar
Department of Studies in Geology, Karnatak University, Dharwad-580003, India
B. Chandan Kumar
Department of Geology, Central University of Kerala, Kasaragod-671123, India
M. A. Malapur
Department of Studies in Geology, Karnatak University, Dharwad-580003, India

Abstract


The petrographic and major element geochemical characteristics clearly suggest that the metavolcanic rocks of Medur Formation in the central part of the Dharwar-Shimoga greenstone belt comprise basalt, andesite, dacite and rhyolite (BADR) sequence. These metavolcanic rocks are metamorphosed to greenschist-amphibolite facies. The basalts show mixed tholeiitic and komatiitic composition. The andesites are mainly tholeiitic, while dacite and rhyolites are calc alkaline nature. Good correlation exists between SiO2 and major oxides, which suggests that these metavolcanic series (BADR) compositions are genetically inter-related and were derived probably from differentiation of magma at different depths.

Keywords


Metavolcanics, Petrography, Geochemistry, Dharwar-Shimoga Greenstone Belt, Dharwar Craton.