Palynological Investigations of Umia Formation of Kutch Basin, Gujarat, vis-a-vis Depositional Environment and Age

Abstract

Mesozoic sedimentary sequence of the Kutch Basin is lithostratigraphically divisible into four formations namely, Patcham Formation, Chari Formation, Katrol Formation and Umia Formation in the ascending stratigraphic order. Two stratigraphic sections viz., Ghuneri Coal Mine Section and Korawadi River Section of Umia Formation were investigated in the present study. The palynological assemblage recovered from the Umia Formation of Kutch Basin comprises 88 species belonging to 48 form genera. Of these, 3 form genera and 9 species are new. These are Venkatapollis indica gen et sp. nov., Aranyasporis cretacea gen. et sp. nov., Pyrgopites mesozoicus gen. et sp. nov., Echninatisporis korawadiensis sp. nov., Concavissimisporites trilobatus sp. nov., Leptolepidites psilatus sp. nov., Cingulatisporites intermedius sp. nov., Taurosporites mesozoicus sp. nov. and Trilobosporites indicus sp. nov. Qualitatively the palynological assemblage of these sections of Umia Formation is dominated by Pteridophytes followed by gymnosperms, bryophytes and fungal spores indicating warm and humid climatic conditions. The age diagnostic palynotaxa such as Crybelosporites, Gabonisporis, Rouseisporites and Aequitriradites which straddle Tithonian-Neocomian time plane are well represented in Bhuj Sections of Umia Formation. The palynotaxa such as Cyathidites, Lycopodiumsporites, Klukisporites, Concavissimisporites, Taurocusporites, Schizisporites and Echinatisporis on the other hand are found to extend even up to the Aptian-Albian time. Hence investigated sediments of the Kutch Basin in all probability are of Early Cretaceous time ranging from Neocomian-Early Aptian.