Palynology of the Barail (Oligocene) and Surma (Lower Miocene) sediments exposed along Sonapur-Badarpur Road Section, Jaintia Hills (Meghalaya) and Cachar (Assam). Part - VI. Palynostratigraphic zonation

Abstract

Excellent exposures of Barail and Surma groups are developed along the Sonapur-Badarpur Road Section in Jaintia Hills (Meghalaya) and Cachar (Assam). Frequency analysis and variation patterns observed in the palynoassemblage from these sediments provide ample evidence for their biostratigraphic zonation. On the basis of the first appearance, maximum development and decline of the various palynofossils, six cenozones have been recognized in the sequence. These are in ascending order: (i) Polysphaeridium subtile Cenozone, (ii) Todisporites major Cenozone, (iii) Lygodiumsporites eocenicus Cenozone, (iv) Striatriletes sinuosus Cenozone, (v) Pinuspollenites foveolatus Cenozone, and (vi) Malayaeaspora costata Cenozone. A formal description of each cenozone, as to their type section, lithology, thickness, nature of contacts, restricted and characteristic spore-pollen species and other salient features, if any, have also been given. The lateral extension of these cenozones has the potential for the correlation and demarcation of equivalent strata in other parts of this region.