Juras-Cretaceous Stratigraphy and Sedimentation Around Jabalpur, M.P., and Their Paleogeographic Implications

The Lameta and jabalpur Groups, which are redefined and described in their type area, are separated by an unconformity at Dalpatpur. The unconformity grades to a paraeonformity of much lesser magnitude in the vicinity of jabalpur town. Local paleocurrents in the type area, directions of truncations and relative rates of change of stratigraphic hiatus across the unconformities and configuration of pre-trappean surface appear to be mutually related to each other. All these features suggest the existence of a westerly slope corresponding to Krishnan's' Narmada Trough' since the Jurassic period. While the Jabalpurs are the products of a typical flood plain in an interior basin, the Lametas appear to represent shallow marine sediments on the stable shelf. The terrigenous constituents of the Jabalpur Group are mainly derived from the pelitic metasediments in the east. The terrigenous constituents of the Lametas, on the other hand, represent a mixed assemblage of detritus derived from the local jabalpurs and pelitic metasediments. Diagenesis of the ]abalpur sediments mainly involves endogenic reconstitution. Exogenic cements in the lametas are mainly derived from the overlying Deccan Trap.