Pb-Pb baddeleyite ages of mafic dykes from the Western Dharwar Craton, Southern India: a window into 2.21–2.18 Ga global mafic magmatism

Baddeleyite is considered as a key mineral for precisely dating silica-poor mafic rocks and is commonly found to crystallize in mafic dykes and sills. Four NW-SE trending mafic dyke samples from the Western Dharwar Craton (WDC) were analysed for Pb-Pb baddeleyite isotopic method and gave a weighted mean age of 2210 Ma. Similar ages have been documented for the mafic dykes of Eastern Dharwar Craton (EDC) and overall they show a giant radiating pattern covering the entire Dharwar Craton. Previous studies have recorded an occurrence of slightly younger dykes i.e. 2180 Ma in the WDC and EDC. Both these generation of mafic dykes are observed to converge beneath the western margin of the Deccan Traps which might be the probable mantle source for them, during that time. Interestingly, similar mafic magmatic events have been reported from the Superior, Slave and Greenland Cratons in the form of radiating dykes and sills. Therefore, on the basis of precise baddeleyite ages, trends, previous studies, a paleogeographic reconstruction sketch map is presented for the Dharwar, Superior, Slave and Greenland Cratons during the Sclavia/Superia configuration. It is also hypothesized that the emplacement of this 2.21-2.18 Ga Large Igneous Province might have initiated break-up of the supercraton Sclavia/Superia.

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P Yadav, D. Srinivasa Sarma, V Parashuramulu (2020) Pb-Pb baddeleyite ages of mafic dykes from the Western Dharwar Craton, Southern India: a window into 2.21- 2.18 Ga global mafic magmatism. Journal of Asian Earth Sciences, https://doi.org/10.1016/j.jseaes.2019.104221 external link.

A possible paleocontinental reconstruction of Sclavia/Superia for the Dharwar, Superior, Slave and Greenland Cratons at ca. 2.21-2.18 Ga.