An interpretation of the palynology and palaeoecology of the Early Miocene Dulte Formation, Mizoram, India

Abstract

A palynological study of the Early Miocene sediments of the Aizawl Basin, Mizoram is presented. The Aizawl Basin is part of the North-East India Dulte Formation (Surma Group: Bhuban Subgroup). The significant elements of the palynoassemblage are: Pteridacidites, Striatriletes, Polypodiisporites and Schizaeoisporites (pteridophytes), Compositoipollenites, Malvacearumpollis, Spinizonocolpites , Bombacacidites, Ctenolophonidite, Polyporina, Polyadopollenites, Graminidites (angiosperms), Cucurbitariaceites, Dicellaesporites and Phragmothyrites (fungi).

The shale contains abundant plant remains and white gastropod shells. The alternation of shale-siltstone, sandstone-claystone and the palynoflora suggest an Early Miocene age for studied sequence. Palaeoecological interpretation based upon recent botanical affinities of the fossil spores and pollen highlights the presence of mangrove, fresh water, swamp and water edge ecological groups. The presence of fungal remains indicates warm and humid climate. The composition of palynological assemblage suggests that Dulte Formation was deposited in deltaic conditions rich in terrigeneous detritus where the fungal elements thrived.