- GeoRef, Copyright 2006, American Geological Institute. Abstract, Copyright, Society of Economic Geologists
The graphite mineralization in the Bulathkohupitiya area was studied with an emphasis on the Bogala deposit.Vein-type mineralization occurs in the zones of deep-seated fractures in supracrustal stratiform metasedimentary rocks resulting from the differential rise of subcrustal migmatites.The mineralization at Bogala comprises several veins of graphite and a large vein of syenite pegmatite. Mineralogical and geochemical study of the wall rocks reveals a well-zoned alteration halo about the deposit. Chemical zoning in the altered wall rock and the relict mineral replacement textures indicate deep-seated hydrothermal activity. Formation of vein graphite by decarbonation of carbonates and reduction of CO 2 formed during the decarbonation reaction is indicated by the available carbon isotope data.Chemical zoning in the alteration halo may be a useful aid in the exploitation of known graphite deposits.