Petrology, geochemistry and geochronology of Neoarchean A-type granite from Alwar Basin, North Delhi Terrane, NW India

A 2.53 Ga old Jhiri granite has been dated using zircon U-Pb systematics from the lowermost succession of North Delhi Terrane (NDT). The granite is an intrusive into the rocks of meta-volcano sedimentary sequence of basal Raialo Group of the Delhi Supergroup. Geochemically, the pluton is peraluminous, magnesian, alkali-calcic to alkali in character with strong negative anomaly for Ba, Ta, P and Ti and positive anomaly for K, Pb and Th. The plots on tectonic discrimination diagrams show the Jhiri granite to be of A-type with an affinity to the volcanic arc related granitoids. The comparison of Jhiri pluton with other Neoarchean granitoids of the Aravalli Delhi Mobile Belt (ADMB) and Bundelkhand craton shows the granite to be more evolved and have strong depletions for HREEs with (La/Yb)(N) >20. A hybrid source, having component of fractional crystallization-derived mafic melt mixing with melt generated by partial melting of early formed felsic crust in a back-arc extension or post-orogenic extension setting is proposed as the possible scenario for the generation and emplacement of Jhiri pluton.