Magnetostratigraphic perspectives and palaeoenvironmental implications of Deccan volcano-sedimentary succession within the Malwa subprovince, Central India

Abstract

The present study examines a composite section representing four basaltic and three intertrappean successions at Gujri locality, Malwa subprovince, Central India. An integrated palaeomagnetic, sedimentological, mineralogical, and palaeontological approach has been utilized to understand the palaeoenvironmental changes in a stratigraphic context. The palaeomagnetic results reveal the presence of C30n/C29r and C29r/C29n magnetic reversals providing the C30n-C29r-C29n magnetostratigraphy for the region that spans almost the entire eruption history of the Deccan volcanism. As the Malwa lava flows contain C30n magnetochron, it represents the earliest basalt flows of Deccan volcanism compared to the Western Ghats sequences. Additionally, the record of the younger C29n magnetochron suggests that the Malwa and Mandla lava flows are magnetostratigraphically correlatable and experienced synchronous volcanic activity with the Western Ghats sequences during the main (C29r) and late (C29n) phases of Deccan volcanic eruption. Sedimentological and palaeontological data support that the intertrappean sediments at the Gujri locality were deposited in a dominantly low to moderate-energy freshwater palustrine-lacustrine environment under tropical to sub-tropical humid conditions with seasonal precipitation. However, data from the topmost intertrappean unit at Gujri possibly hints at ‘Mock’ aridity across the C29r/C29n transition.