A subsurface criterion for predictive exploration of kimberlites from Bouguer gravity in the eastern Dharwar craton, India

Abstract

The Archaean-Proterozoic Dharwar craton has many recorded occurrences of diamondiferous kimberlites. Reports of kimberlite emplacement in parts of the tectonically complex eastern Dharwar craton and a significant density contrast between kimberlites and the host peninsular gneisses motivated us to conduct gravity studies in the NarayanpetIrladinne area of the eastern Dharwar craton. This region is contiguous with the Maddur-Narayanpet kimberlite that lies to its north, while the river Krishna lies to its south.From observed association of reported kimberlites in the Maddur-Narayanpet field with subsurface topography of the assumed three-layer earth section obtained by Bouguer gravity modelling, we developed a subsurface criterion for occurrence of kimberlites in the present study area. Using this criterion, five potential zones for kimberlite localization were identified in the Narayanpet-Irladinne region, eastern Dharwar craton.