Early Holocene pollen data from Mikir Hills, Assam, India

Abstract

The pollen analytical studies of a 1.5 m deep soil profile (12210±110 years BP at 80 cm level) from Kaki Forest Division in Mikir Hills of Assam have been carried out. The pollen investigation of surface samples was made to understand the pollen/vegetation relationship in the forest. However, the study of surface samples does not fully cohere with the present day set up of vegetation. Palynological studies of the sediment profile indicate that since the last 15,000 years there have been three stages of vegetational developments followed by a reducing environment at the beginning (150-120 cm) reflecting directly on brief phases of climate such as arid, semi arid and warm and humid. The abundance of grasses both cultivated as well as wild throughout the pollen diagram has revealed the existence of an open savanna forest for a long period. The arboreal vegetation is represented by mixed tropical and subtropical trees and shrubs. Both monolete and trilete ferns are well documented in the assemblage. Occurrence of some degraded pollen and spores indicate the biodegradation of microbiota as evidenced by the presence of fungal spores and hyphae in almost all the sediments.

The low occurrence of extra regional plant taxa like Pinus, Picea, Abies, Larix, Betula and Alnus in the sediments is indicative of long distance transportation of pollen from high elevation.