Palynological investigation of the kherapara formation (oligocene) exposed along tura-dalu road near Kherapara, west Garo Hills District, Meghalaya, India

Abstract

A diversified palynofloral assemblage has been recovered from the Kherapara Formation (Oligocene) exposed along Tura-Dalu Road near Kherapara. West Garo Hills District. Meghalaya. India. The palynoflora is represented by 53 genera and 77 species of algal and fungal remains, pteridophytic spores and gymnospermous and angiospermous pollen. Of these, three species, viz. Garotriletes kheraparaensis, Striatriletes tetradites and Echistephanocolpites quadrangullaris have been proposed as new. Reworked Permian and Cretaceous palynofossils (10 genera and 11 species) have also been recorded. The assemblage is dominated by pteridophytic spores followed by angiospermous and gymnospermous pollen. Based on palynofossil distribution. the Kherapara Formation is divisible into two cenozones. viz., Polyadopollenites sahii Cenozone and Striatriletes spp. Cenozone which can be recognised by their characteristic and restricted palynotaxa. On the basis of affinity with the modem plant families represented in the assemblage and dominance of pteridophytic spores, a tropical-subtropical (warm-humid) climate has been suggested. The assemblage contains a mixture of ecological groups such as lowland. fresh water swamp and water edge, montane, mangrove and back-mangrove and sandy beach elements. The palynoflora indicates a coastal marine depositional environment of deposition having fresh water connections with swamps and ponding conditions nearby.