Paleogeography of India at ∼1.8 Ga: New constraints from baddeleyite geochronology and paleomagnetism of mafic dykes from the Dharwar craton

Abstract

The paleogeographic position of Dharwar craton/India within Paleoproterozoic supercontinent configurations has been well demonstrated using highly reliable key paleopoles from ∼2.37 Ga to ∼1.86 Ga mafic events in recent studies. Here, we report a paleomagnetic pole at ∼1.8 Ga along with a precise Pb-Pb baddeleyite age. The emplacement age of an NW-SE trending dolerite dyke yields a weighted mean age of 1799 ± 0.8 Ma (MSWD = 0.7), which coincides with earlier reported U-Pb baddeleyite age (1794 ± 7 Ma) and confirms the existence of significant emplacement of Pebbair dyke swarm at ∼1.8 Ga. Paleomagnetic results from eleven sites shows mean D = 306°, I = 31°, α95 = 10° (k = 23), and corresponding paleopole is calculated at 38°N, 357°E (dp = 6.1° and dm = 11°). These remanent directions are carried by the pseudo-single domain (PSD) magnetite. This pole passes the paleosecular variation test of the geomagnetic field and fulfills the reliability criteria (R = 5) of Meert et al. (2020), so, suggested to be a key pole for Dharwar craton/ India (∼1.8 Ga). The paleopositon of Dharwar craton is occupied at shallow paleolatitude and drifted towards the north with a minimum velocity (∼5.7 cm/yr) from ∼1.86 Ga to ∼1.80 Ga. The paleogeographic reconstruction model at ∼1.8 Ga has been attempted with available coeval paleopoles from other global cratons. The Dharwar craton (South India block), the Amazonia craton, and the Baltica craton have assembled at ∼1.86 Ga, and North Australia, Sao Francisco, Rio de la Plata cratons came in close to the South India block, Amazonia, and Baltica assembly at ∼1.80 Ga.