Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

A. P. Tewari ¹, P. K. Swain ¹, Chhaya Sharma ²

Affiliations
1 311, Sector 7A. Chandigarh, IN
2 Birbal Sahni Institute of Palaeobotany, Lucknow, IN

Abstract

During the course of clay investigation near Kalidhang, District Sirmur, Himachal Pradesh, some well preserved plant leaves were found in the varve type clays and a sample of it was also analysed for pollen studies. This note records interesting pollens of Pinus roxburghie. Gramineae, Oleaceae Quercus etc., including an abnorma13-winged pollen of Pinus and a large sized Gramineae pollen.

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Chhaya Sharma ¹, M. S. Chauhan ², R. Sinha ³

Affiliations
1 Department of Geology, University of Lucknow, Birbal Sahni Institute of Palaeobotany, Lucknow - 226 007, IN
2 Birbal Sahni Institute of Palaeobotany, Lucknow - 226 007, IN
3 Indian Institute of Technology, Kanpur - 208 016, IN

Abstract

Pollen analysis of a sediment core from Priyadarshini Lake (Core S3), East Antarctica, has revealed the climatic oscillations in the region since Holocene. Three pollen zones have been identified on the basis of recovered pollen taxa and varying frequencies. Between 10,000 and 9,000 yr BP, cold and dry climate prevailed in the region as reflected by the dominance of grasses, Acritarch and very low frequencies of Cosmarium - a fresh water alga. The lake was probably shallow and smaller in dimension during this period. Between 9,000 to 2,400 yr BP, relative increase in grasses is witnessed though in fluctuating frequencies. Cosmarium also exhibits a distinct increasing trend, whereas Acritarch declines considerably. This overall change in the assemblage reflects the onset of warm and moist climate and the lake had a wider expansion during this phase on account of amelioration in climate than witnessed before. Between 2,400 and 1,000 yr BP, relatively reduced frequencies of grasses, coupled with total disappearance of Cosmarium, demonstrate that the climate changed once again to cold and dry. However, 1,000 yr BP onwards, marked increase in grasses coupled with exceedingly high values of Cosmarium implies that the climate ultimately turned warm and moist.

Keywords

Palynology, Holocene, Climate Changes, Priyadarshini Lake, Antarctica.

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