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      https://www.ias.ac.in/article/fulltext/jess/120/04/0627-0641

    • Keywords

       

      Daba mafic rocks; geochemistry; magnetic fabric; neoproterozoic; Phulad ophiolite; NW India.

    • Abstract

       

      A small isolated mafic body occurs to the south of Sirohi near village Daba within the Neoproterozoic Erinpura Granite in the southern sector of the Proterozoic Delhi Fold Belt in NW India. This mafic body occurs close to a 100 m wide NE–SW trending shear zone (Daba Shear Zone) which overprints the felsic rock fabrics. Further south, a small mafic body near village Kui was also sampled which forms the southern limit of the Phulad Ophiolite Suite which is a 300 km long major NE–SW trending lineament, described as Western Margin Fault. Some of the lithological components of the Daba mafic body show locally preserved magmatic fabric but completely transformed mineralogies under lower amphibolites facies metamorphic conditions where two-stage deformation has been inferred. Magnetic fabric analysis underlines a general correspondence of structural elements in both felsic and mafic lithologies. Binary correlations of Zr with other high field strength elements underline fractionation as the main process in the evolution of Daba and Kui rocks. Geochemical characteristics indicate subalkaline tholeiitic basalt affinity for these mafic rocks. The trace element characteristics, such as enriched LIL elements, high Th, absence of negative Nb anomalies and depletion in compatible elements in Daba samples suggest an enriched mantle source and lower degree of melting. The trace and rare earth element characteristics for Kui (Th anomaly, Nb–Ta trough and less spiked patterns, flat REE trends) indicate derivation from a refractory mantle source affected by fluids derived from subduction. Distinct differences in trace and REE characteristics between Daba and Kui can be interpreted in terms of different stages of ophiolite development.

    • Author Affiliations

       

      M K Pandit1 H De Wall2 H Daxberger2 J Just2 M Bestmann2 K K Sharma3

      1. Department of Geology, University of Rajasthan, Jaipur 302 004, India.
      2. GeoZentrum Nordbayern, Universit¨at Erlangen-Nürnberg, Schlossgarten 5, D-91054 Erlangen, Germany.
      3. Department of Geology, Govt. PG College, Sirohi 307 001, India.
    • Dates

       
  • Journal of Earth System Science | News

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