New paleomagnetic results on $\sim$2367 Ma Dharwar giant dyke swarm, Dharwar craton, southern India: implications for Paleoproterozoic continental reconstruction

Abstract

Here we report new paleomagnetic results and precise paleopole position of the extensional study on $\sim$2367 Ma mafic giant radiating dyke swarm in the Dharwar craton, southern India. We have sampled 29 sites on 12 dykes from NE–SW Karimnagar–Hyderabad dykes and Dhone–Gooty sector dykes, eastern Dharwar craton to provide unambiguous paleomagnetism evidence on the spectacular radiating dyke swarm and thereby strengthening the presence of single magmatic event at $\sim$2367 Ma. A total of 158 samples were subjected to detailed alternating field and thermal demagnetization techniques and the results are presented here along with previously reported data on the same dyke swarm. The remanent magnetic directions are showing two components, viz., seven sites representing four dykes show component (A) with mean declination of $94{{}^{\circ }}$ and mean inclination of $-\,70{{}^{\circ }}$ ($\hbox {k}=87$, $\upalpha _{95}=10{{}^{\circ }}$) and corresponding paleopole at $16{{}^{\circ }}\hbox {N}$, $41{{}^{\circ }}\hbox {E}$ ($\hbox {dp}=15{{}^{\circ }}$ and $\hbox {dm}=17{{}^{\circ }}$) and 22 sites representing 8 dykes yielded a component (B) with mean declination of $41{{}^{\circ }}$ and mean inclination of $-\,21{{}^{\circ }}$ ($\hbox {k}=41$, $\upalpha _{95}=9{{}^{\circ }}$) with a paleopole at $41{{}^{\circ }}\hbox {N}$, $200{{}^{\circ }}\hbox {E}$ ($\hbox {dp}=5{{}^{\circ }}$ and $\hbox {dm}=10{{}^{\circ }}$). Component (A) results are similar to the previously reported directions from the $\sim$2367 Ma dyke swarm, which have been confirmed fairly reliably to be of primary origin. The component (B) directions appear to be strongly overprinted by the 2080 Ma event. The grand mean for the primary component (A) combined with earlier reported studies gives mean declination of $97{{}^{\circ }}$ and mean inclination of $-\,79{{}^{\circ }}$ ($\hbox {k}=55$, $\upalpha _{95}=3{{}^{\circ }}$) with a paleopole at $15{{}^{\circ }}\hbox {N}$, $57{{}^{\circ }}\hbox {E}$ ($\hbox {dp}=5{{}^{\circ }}$, $\hbox {dm}=6{{}^{\circ }}$). Paleogeographical position for the Dharwar craton at $\sim$2367 Ma suggests that there may be a chance to possible spatial link between Dharwar dykes of Dharwar craton (India), Widgemooltha and Erayinia dykes of Yilgarn craton (Australia), Sebanga Poort Dykes of Zimbabwe craton (Africa) and Karelian dykes of Kola-Karelia craton (Baltica Shield).