Does the Kutch offshore basin record India's Continental breakup history from Africa to Seychelles?

The breakup of Gondwanaland led to the creation of many rift basins, of which the Kutch basin is one. Previous geochronological studies of the Kutch onshore rocks have established multiple episodes of magmatism ranging from 124-60 Ma. The wells drilled on the Kutch offshore basin also encountered magmatic rocks at various depths, but their temporal relationship is not constrained.

                The present study reports the Ar-Ar ages of 5 igneous rocks from the Kutch offshore wells. As determined by petrographical and geochemical analysis, these samples comprise two basalts(b), two dolerites(d), and a rhyolite(r). The plateau ages of the samples are 80.5 ± 0.5(b), 81.4 ± 0.5(r), 100.3 ± 0.6(b), 72.6 ± 0.4(d), and 67.1 ± 0.6(d) (errors quoted at 2σ level). These ages establish magmatism offshore from 100 to 67 Ma. There are several levels where magmatic rocks occur in these wells. Dolerite stringers in Early Cretaceous to middle Jurassic sedimentary rocks have been reported from a few wells.

                The geochronology data from the Kutch onshore and adjoining areas in Rajasthan show a magmatic record from 190-60 Ma. There is a possibility that some magmatic rocks in the Kutch offshore basin encountered in different wells may also record the older magmatism and events from the break-up of Gondwana to Seychelles, thereby unfolding the tectono-magmatic history of this region.