The Bhetkheda–Mohana Lineament is traced as a continuous lineament across nearly 100 km in the central Narmada valley across the Deccan Trap basalts and their basement of Proterozoic sediments. While a major length of this lineament is occupied by a basaltic dyke, there are segments where the dyke is completely absent, and the lineament is represented by a regional fracture/shear/fault zone. At its eastern extremity, this dyke is exposed intruding along the axis of a synclinorium of the Vindhyan Supergroup sediments, as a 4-km long string of hillocks of picturesque columnar jointed basalt. It has the presence of ignimbrites and a thin basaltic flow (resting on the sediments) surrounding it, suggesting the presence of an eruptive vent. This dyke intrudes the Mandleshwar Formation lava flows dated at 67–66 Ma and is associated with the Narmada dyke swarm. It has given $^{40}$Ar/$^{39}$Ar age of 66.6±0.5 Ma. Its chemical characters conform to those of the basaltic flows of the Malwa Traps, indicating a common source and emplacement history. This is a unique example of a dyke that was emplaced along a preexisting fracture zone cutting through the Proterozoic basement as well as the Deccan Trap lavas, with a distinct petrological identity with the host lava flows, indicating its feeder relation. It endorses the comparison of the Icelandic mode of fissure-fed flood basalts with the eruptive history of the Deccan Volcanic Province.

The Western Ghats sections of the Deccan Volcanic Province (DVP) are considered the ‘type area’ for most of the established models of its eruptive history and age. The prevailing chemostratigraphy and lithostratigraphy of the Western DVP based on the study of these sections are largely comparable but have subtle conceptual and practical differences. Although based on higher resolution data, the latter failed to get widespread acceptance. Horizons of giant phenocryst basalts (GPBs) have been used in both stratigraphic classifications as marker horizons. They can be traced across many tens of kilometers andserve as efficient and easy-to-map horizons during field mapping. We demonstrate the lateral continuity of the GPB horizons across the Western DVP to reiterate their relevance in the stratigraphic classification of the otherwise uniform pile of basaltic flows. We propose a unified stratigraphy for this subprovince, which reconciles existing chemostratigraphic and lithostratigraphic classifications.