Geochronology and geochemistry of Meso- to Neoarchean magmatic epidote-bearing potassic granites, western Dharwar Craton (Bellur-Nagamangala-Pandavpura Corridor), southern India; implications for the successive stages of crustal reworking and cratonization

We present field, petrographic characteristics, zircon U-Pb ages, Nd isotopes, major and trace element data for the magmatic-epidote bearing granitic plutons in Bellur-Nagamangala-Pandavpura corridor and address successive reworking and cratonization events in the western Dharwar craton (WDC). U-Pb zircon ages reveal three stages of plutonism including: (i) sparse 3.2 Ga granodiorite plutons within the TTG basement (ii) 3.0 Ga monzogranite to quartz monzonite plutons adjoining the Nagamangala greenstone belt and (iii) 2.6 Ga monzogranite plutons in the Pandavpura region. Elemental data of the 3.2 Ga granodiorite indicate their origin through melting of mafic protoliths without any significant residual garnet. REE patterns of 3.0 Ga plutons with negative Eu anomalies and Nd isotope data with epsilon (sub Nd) (T) = 3.0 Ga ranging +0.5 to -1.7 indicate major crustal source with minor mantle input. Poorly fractionated REE patterns with negative Eu anomalies of 2.6 Ga plutons suggest plagioclase in residue. The presence of magmatic epidote in all the plutons points to their rapid emplacement and crystallization ca. 5 kbars. The three groups of plutons correspond to successive stages of reworking linked to melting of deep crust and cratonization of WDC during 3.2 Ga, 3.0 Ga and 2.6 Ga.