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.