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      https://www.ias.ac.in/article/fulltext/jess/128/01/0019

    • Keywords

       

      Aravalli craton; Delhi Supergroup; S-type granite; tungsten mineralisation; geochemistry; geochronology.

    • Abstract

       

      Neoproterozoic granites are widespread in the Delhi Fold Belt of the Aravalli craton, some of which are associated with tungsten mineralisation. In one such instance, the volcano-sedimentary sequence of Barotiya Group in the South Delhi Fold Belt is intruded by a pluton of biotite granite gneiss known as Sewariya Granite (SG) and later by stocks and dyke swarm of tourmaline leucogranite known as Govindgarh Granite (GG). GG magmatism was associated with wolframite mineralisation in hydrothermal quartz veins occurring along the sheared contact between SG pluton and Barotiya mica schist. SG pluton shows the evidence of ductile and brittle deformations, whereas GG is by and large undeformed. Apart from quartz and feldspars, SG contains biotite and muscovite, and GG contains muscovite, tourmaline and garnet. Although both SG and GG are peraluminous, SG has a wide range of SiO$_{2}$ and narrow range of alkalis, and GG has a narrow range of SiO$_{2}$ and a wide range of alkalis. REE (rare Earth elements) modelling shows that the parent magma of SG and GG was derived from partial melting at different crustal levels. Rb–Sr isotope data of GG yield a mineral isochron age of 860 $\pm$ 7.4 Ma which represent the time of igneous crystallisation and cooling of the granite to less than 400$^{\circ }$C.

    • Author Affiliations

       

      Sivasubramaniam R1 2 Vijay Anand Sundarrajan3 Pandian M S1 Balakrishnan S1

      1. Department of Earth Sciences, Pondicherry University, Puducherry 605 014, India.
      2. Atomic Minerals Directorate for Exploration and Research, Shillong 793 019, India.
      3. Department of Earth Sciences, Eritrea Institute of Technology, Asmara 12676, Eritrea.
    • Dates

       
  • Journal of Earth System Science | News

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