Abstract
In northwestern India, the South Delhi Fold Belt (SDFB) is a NE-SW trending Proterozoic fold belt. The Phulad Shear Zone (PSZ), characterised by mylonites, marks its western margin, formed around ∼820Ma in a ductile transpressional regime with a top-to-the-NNW reverse movement. Isolated reports of ∼1Ga granites within the SDFB correlate-in time with the Rodinia supercontinent assembly. These pink, foliated, equigranular granites, named Foliated pink granite, occur in a 6-12km wide, 200km long linear belt. Detailed investigations reveal synchronous deformation in both granites and PSZ mylonites. Geochemically, these granites are ferroan, calc-alkalic and dominantly metaluminous. Tectonic discrimination diagrams confirm A-type within-plate-granite characteristics, indicating emplacement in an extensional regime. U-Pb zircon dating of the granites yields a magmatic Concordia age of 970.7±2.9Ma, overprinted by a metamorphic age of 826.3±6.9Ma. This study documents similar magmatic and post-magmatic features across all ∼1Ga granites. Field, petrological, geochemical and geochronological data suggest Foliated pink granites originated from lower crustal melting during crustal thinning at ∼970Ma, followed by thrusting and deformation at 820-810Ma, coinciding with PSZ formation. Our study concludes that NW India lacks any geological evidence of Rodinia assembly, which is crucial for accurately reconstructing Rodinia's palaeogeography and understanding the role of India within Rodinia.
Published Version
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