The Kaladgi Basin is one of the several Proterozoic sedimentary basins of India. This basin has a binary evolutionary history with an angular unconformity separating the older deformed and younger undeformed rock sequences of the Kaladgi Supergroup, named the Bagalkot and Badami Groups, respectively. The Bagalkot Group is believed to be of late Paleoproterozoic to Mesoproterozoic in age. However, the timings of deposition of the Badami Group and the closure of the basin have remained speculative. Our 206Pb-207Pb dating of the youngest unit of the Supergroup, the Konkankoppa Limestone yielded a depositional age of 604 ± 25 Ma (MSWD=1.2). This age, considered together with the lowest 87Sr/86Sr ratio of 0.70781 observed in the formation, extends the active sedimentation of the Badami Group well into the Ediacaran Period. These data confirm the existence of a long duration depositional hiatus, of >500 million years, between the Bagalkot and the Badami Groups. Results of this study also refutes the claim that the sedimentation in most of the Proterozoic basins of peninsular India ended by 1000 Ma.

Bibliographic Info: Bivin G. George, Jyotiranjan S. Ray, Pillai, S. P., Mahala, M. K., Kumar, S., Kale, V. S. (2023). C-Sr-Pb isotope systematics of the carbonate sequences of Kaladgi Supergroup, India: Implications for basin evolution and correlation with Proterozoic global events. Precambrian Research, Vol. 388, Art. 107014.
https://doi.org/10.1016/j.precamres.2023.107014.

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