摘要：Abstract We present new 40Ar-39Ar plagioclase crystallization ages from the dykes exposed at the northern slope of the Satpura Mountain range near Betul-Jabalpur-Pachmarhi area, ∼800 km NE of the Western Ghats escarpment. Among the two plateau ages, the first age of 66.56 ± 0.42 Ma from a dyke near Mohpani village represents its crystallization age which is either slightly older or contemporaneous with the nearby Mandla lava flows (63–65 Ma). We suggest that the Mohpani dyke might be one of the feeders for the surrounding lava flows as these lavas are significantly younger than the majority of the main Deccan lavas of the Western Ghats (66.38–65.54 Ma). The second age of 56.95 ± 1.08 Ma comes from a younger dyke near Olini village which cuts across the lava flows of the area. The age correlates well with the Mandla lavas which are chemically similar to the uppermost Poladpur, Ambenali and Mahabaleshwar Formation lavas of SW Deccan. Our study shows that the dyke activities occurred in two phases, with the second one representing the terminal stage. Graphical abstract Display Omitted Highlights • 40Ar-39Ar ages of 66.56 ± 0.42 Ma and 56.95 ± 1.08 Ma from plagioclase separates in Satpura dyke. • The younger age of the dyke signifies post-Deccan age. • Former dykes are pre- or coeval that fed to lavas, whereas the latter represent terminal stage.
关键词：Keywordsen 40Ar-39Ar agesDeccan dykesBetul-Jabalpur-Pachmarhi areaNarmada-Tapi dyke system
