Petrogenesis of the 1.85 Ga Sonakhan mafic dyke swarm, Bastar Craton, India

The NNW trending tholeiitic Sonakhan mafic dyke swarm of the Northern Bastar Craton is comprised of basalt to basaltic andesite (SiO2 = 46.3 wt% to 55.3 wt%; Mg# = 37 to 70) dykes. A single basaltic dyke yielded a weighted-mean 207Pb/206Pb baddeleyite age of 1851.1 ± 2.6 Ma. The Sr and Nd isotopes (87Sr/86Sri = 0.70396 to 0.70855; εNd(t) = −5.7 to +2.0) are variable which is a consequence of crustal contamination. Trace element modeling suggests...