Mesozoic stratigraphic framework in India with focus on the jurassic geological record in the kachchh basin

Abstract

It updates the biostratigraphic refinement in the Indian Mesozoics with focus on the Triassic in Spiti, Jurassic in Kachchh, and Cretaceous in Kachchh and Cauvery. As an example, the ammonoid stratigraphic zonation in Kachchh basin inclusive of the new Oxfordian zones, as also the origin of the basin are developed at length. Also are touched upon the salient pre-sequence Paleozoic features as back drop, along with the start and termination of the sequence. State of the art is presented on the integrated high resolution scales for the three periods. The Early- amd Middle Triassic update includes integration of ~35 ammonoid zones to ~15 conodont zones in the lithostratigraphically and splendidly resolved Spiti sections. The Indian Late Triassic to Early Jurassic is largely ammonoid devoid but for scanty Early Jurassic presence at Lamayuru in Ladakh. The Jurassic includes ~35 ammonoid zones, over 50 subzones, and yet more number of Horizons in the Middle and Late in well-resolved Kachchh sections. The Cretaceous update is compositely presented of 18 informal ammonoid zones with ammonoid presence almost in all the 12 stages in some or other Indian basin yet lacking the desired level of lithostratigraphic differentiation. © Springer Science+Business Media Singapore 2017.