Early alkaline magmatism in the Deccan Traps: Implications for plume incubation and lithospheric rifting

Abstract

Significant lithospheric extension, which usually accompanies continental flood volcanism, has been generally thought to always follow the main volcanic episode. However, plume-derived, uncontaminated, early alkaline magmas from the Deccan Traps, India, indicate considerable lithospheric extension similar to 3 million yrs (MY) before the main tholeiitic phase. Indeed, such early alkaline magmatism known from many flood-basalt provinces of the world seems a necessary and natural consequence of plume head incubation, with lithospheric doming and rifting. (C) 1997