Palynostratigraphic, palaeoenvironmental and palaeogeographic significance of the Early Cretaceous palynoflora of Kachchh Basin, western India

Abstract

Sediments of Bhuj Formation (Early Cretaceous) occur in the Kachchh Basin, western India containing abundant and diverse plant fossils. Sedimentary successions of the formation exposed along Pur River comprise variably thickened shale, carbonaceous shale, thin coal seam, siliceous clays, etc. and have yielded abundant megaspores, microspores, conifer pollen grains, dinoflagellate cysts and colonies of Botryococcus alga. Two palynozones are recognized in the recorded palynoassemblage, viz. Minerisporites cutchensis megaspore zone at the basal part, derived mostly from herbaceous vegetation growing along pro–deltaic swampy habitat. The succeeding Araucariacites australis zone in the upper part of the succession probably derived from conifer–dominated forest inhabited along the freshwater swamps, flourishing in a more humid and warm temperate climate. The palynofloras of both palynozones are biostratigraphically very significant indicating Late Aptian–Early Albian age of the succession. A majority of the palynotaxa recorded from the studied sedimentary succession show resemblance with the contemporaneous deposits of other Gondwana continents of the Southern Hemisphere.