1995-96 - Birbal Sahni Institute of Palaeobotany

1995-96
yrs B. P. at base from Wadda Lake. Pithoragarh, U.P.. shows vegetation and climate changes
during major part of Weichselian. During pre 40,000 to 33.000 yrs B.P. climate was probably
cold and dry, not conducive for plant covers. However. distinct climatic amelioration
has been noticed during 30-28.000 yrs B.P.. \\hen local tree taxa JUniperus, Helula, Larix
arc \\ell represented along with high influx of pollen from lo\\er altitude. During 28-26,000
yrs B.P. climate was again reverted to\\ards aridity indicated by the decline of tree elements.
During 26.000 B.P. onwards desertic conditions might have prevailed around this sitc
\\ hen sediments are found almost devoid of spores and pollen.
A. Bhattacharyya [& B.S. Kotlia (NainitaJ)]
Under fNSA visiting Fellowship at the Earth Science Division, Physical Research
Laboratory collaborative research work on quantitative envirorunental changes in ti,e Himalayan
region using multiproxydata was undertaken. During this tenure. 98 samples of
five years block from a disc of Abies pindrow dated 1496 to 1994 AD collected from
Dokriani Bamak glacier, Garhwal Himalaya were processed and cellulose were extrated
from these samples for carbon and hydrogen isotope studies.
Stable isotopes of Oxygen ("0) and Carbon (13C) were also analysed from carbonate
rich 107 samples from T5D1 bore hole core and 10 samples from TP 6 bore·hole core of
Tsokar Lake. Ladakh. Secular variations of these two isotopes in these two bore cores at
different depths indicate several dry and wet phases in Tsokar Lake during Weichselian.
Stable isotope ratios of carbon was also analysed from a few samples of these two bore cores
from organic fraction of these sediments. These values in the present study range from 14.6
to -25.7'% indicating dominance ofbotll