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      https://www.ias.ac.in/article/fulltext/jess/102/02/0399-0413

    • Keywords

       

      Malanjkhand; copper deposit; granitoids; geochronology; isochrons; initial ratio; temporal relation

    • Abstract

       

      On the basis of field relations, petrography and chemistry, three types of granitoids are recognized at Malanjkhand in and around the copper deposit over an area of about 200 km2. These are (i) a fine grained ‘leucogranite’ of restricted occurrence in the surrounding area (Gr-I); (ii) coarse-grained, grey in most parts, gneissose granitoid of regional extension (Gr-II); and (iii) the pink-feldspar bearing massive type hosting the mineralization with occasional representatives in the surrounding country (Gr-III). Gr-I comes out as a distinct entity on the basis of cross-cutting relation and mineralogical and chemical composition, the Rb-Sr whole rock isochron also giving a younger age than the other two groups irrespective of the regression model used. Gr-II comes out as the oldest unit but its age relationship with Gr-III cannot be established unequivocally. An uncorrelated error regression model establishes the age relationship as Gr-I<Gr-III<Gr-II, whereas a two-error regression model establishes temporal closeness between Gr-II and III.

    • Author Affiliations

       

      M K Panigrahi1 2 A Mookherjee1 2 G V C Pantulu3 K Gopalan3

      1. Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur - 721 302
      2. Department of Geological Sciences, Jadavpur University, Calcutta - 700 032
      3. National Geophysical Research Institute, Uppal Road, Hyderabad - 500 007
    • Dates

       
  • Journal of Earth System Science | News

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