Geochemistry of the Unusual Mafic Intrusions in Betul Fold Belt, Central India: Implications for Ni-Cu-Au-PGE Metallogeny

Abstract

We report here the recent occurrence of native gold and platinoids, associated with Fe-Ni-Cu-Pb-Zn sulphides and tungsten-bearing phases in the gabbroic intrusions emplaced in the Betul-Chhindwara Belt in the Central Indian Tectonic Zone (CITZ). The ore minerals are represented mainly by native gold, pentlandite, chalcopyrite, pyrite, bowieite and rare phases of tungsten, cadmium and palladium, which were identified by scanning electron microscopy. The whole rock geochemistry shows anomalous Ni-Cu and platinum group elements (PGE) in which palladium is always higher in concentration than in platinum. The inter-element relationships of PGE such as Pd versus Ir and Pt versus Ir indicate their fractionation by a sulphide phase and also suggest that the parental magmas are primitive in nature having high-Mg, low- Ti characteristics, which indicate the boninitic/picritic nature of magmas. A thorough investigation is essential for exploring the Betul mafic-ultramafic intrusions for proving their potential as the host rocks for Au and Ni-Cu-PGE ores.