Dyke Swarms in the Dharwar Craton: A Key to Understanding the Late Archean to Early Proterozoic Cratonic Correlations

Abstract

Mafic dyke swarms are abundantly distributed in the Archean Dharwar craton. Previous studies have focused mainly on the major mafic dyke swarms in EDC; however, those in the WDC are yet to be studied in detail. Here we present preliminary geochemical data for the dykes in the Tiptur area, WDC and compare them with the dyke swarms in the EDC. Petrological studies indicate that the dykes in the Tiptur area fall into two distinct groups. The NW–SE trending dolerite dykes are unaltered, with characteristic ophitic textures and are geochemically comparable to 2.3 Ga EDC dykes. In contrast, the NE–SW trending meta-doleritic dykes showed high degree of alteration. The difference in petrography, major, trace and rare earth element geochemistry between the dolerites and meta-dolerites lead to a preliminary inference that these two suits of rocks might not be co-genetic. Meta-dolerites have not been reported from the EDC and it is possible to assume that they are a part of an earlier event, restricted in WDC, that might have emplaced prior to the amalgamation of WDC and EDC. In a global perspective, we compare our results with those reported in Archean cratons during late Archean to early Proterozoic around the world to constrain similarities that can lead to understanding the global scale magmatic activity and to aid in correlations between cratons.