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Petrogenesis of Proterozoic Lamprophyres from the Western Dharwar Craton, southern India

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dc.contributor.advisor Rao, N V Chalapathi en_US
dc.contributor.author VERMA, DEVESH en_US
dc.date.accessioned 2020-06-15T07:16:31Z
dc.date.available 2020-06-15T07:16:31Z
dc.date.issued 2020-06 en_US
dc.identifier.uri http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/4706
dc.description.abstract The Proterozoic Harohalli dyke swarm lies in the Dharwar craton. Some of these dykes were sampled from Mysore to investigate the sub-surface geology of the region. Lamprophyre samples were collected since they act as windows to the SCLM. Microscopy gave characteristic lamprophyric features – panidiomorphic-porphyritic texture with amphibole and clinopyroxene as phenocrysts and feldspar as groundmass. EPMA analysis revealed the presence of two types of amphiboles – magnesiohastingsite (primary) and actinolite (secondary). Diopsidic augite was also present. The lamprophyre was identified to be Vogesite – a calc-alkaline lamprophyre. The lamprophyres are shoshonitic and high-K in nature. Whole-rock geochemistry showed Nb-Ta-Ti negative anomaly along with Pb, K and Sr enrichment. A negative Hf-Zr anomaly and depletion of HREE was observed. However, due to U depletion, low Mg# and Ni concentration, crustal contamination appeared to be practically absent, and with the help of tectonic discrimination diagrams, a subduction zone tectonic setting has been suggested. The petrogenesis was pinned down to low degrees of partial melting of subduction fluid-metasomatised depleted mantle followed by high degrees of fractional crystallisation, through discrimination diagrams and petrogenetic modelling. A phlogopite garnet lherzolite source was estimated, and the metasomatized mantle was simulated by mixing average global subducting sediments and depleted mantle. en_US
dc.language.iso en en_US
dc.subject Western Dharwar Craton en_US
dc.subject Shoshonitic Lamprophyres en_US
dc.subject Subduction en_US
dc.subject 2020 en_US
dc.title Petrogenesis of Proterozoic Lamprophyres from the Western Dharwar Craton, southern India en_US
dc.type Thesis en_US
dc.type.degree BS-MS en_US
dc.contributor.department Dept. of Earth and Climate Science en_US
dc.contributor.registration 20151005 en_US


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  • MS THESES [1705]
    Thesis submitted to IISER Pune in partial fulfilment of the requirements for the BS-MS Dual Degree Programme/MSc. Programme/MS-Exit Programme

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