Mesoproterozoic ⁴⁰ Ar– ³⁹ Ar ages of some lamproites from the Cuddapah Basin and Eastern Dharwar Craton, southern India: implications for diamond provenance of the Banganapalle Conglomerates, age of the Kurnool Group and Columbia tectonics

Abstract We report Mesoproterozoic 40 Ar– 39 Ar (whole-rock) ages of lamproites from (i) the Ramadugu field (R4 dyke : 1434 ± 19 Ma and R5 dyke: 1334 12 Ma) Krishna (Pochampalle 1439 3 Tirumalgiri 1256 Eastern Dharwar Craton (EDC) (ii) Garledinne (1433 8 Chelima (1373 6 dykes within Paleo-Mesoproterozoic Cuddapah Basin, southern India. The reported for constitute their first radiometric dates. Ages Pochampalle this study are broadly comparable to previously (phlogopite) c. 1500 1418 Ma, respectively. all these much older than those 1.1 Ga kimberlites Wajrakarur Narayanpet fields EDC 1.09 lamproitic at Zangamarajupalle which intrude Cumbum Formation Basin. However, age lamproite ( is similar that Ramannapeta 1224 field. Our provides evidence protracted ultrapotassic (lamproitic) magmatism 1.43 over a widespread area 2500 km 2 ) in around Basin EDC. Implications obtained new diamond provenance Banganapalle Conglomerates, Kurnool Group timing break-up supercontinent Columbia/Nuna explored.