Organisational Structure - Birbal Sahni Institute of Palaeobotany

Birbal Sahni Institute of Palaeobotany
However, further detailed work on the K/T boundary
is necessary to demarcate a precise transition.
K. Ambwani [R.K. Kar & A. Sahni]
Project : The transition of lacustrine fauna and
Floral Communities across Pleistocene-
Holocene in Jammu and Ladakh (Sponsored
by DST, New Delhi, No. DST/ESS/CA/A4—22/
96)
Continued the pollen analysis of the 38 m
deep sedimentary profile from Surinsar Lake. The
studies have unraveled the vegetation history of Early
Holocene. Prepared the manuscript entitled
“Holocene climatic inferences from lacustrine
sediments from Surinsar Lake, Jammu”. Also
completed pollen analysis of part of another profile
from Mansar Lake. Undertook field trip to Jammu
and collected large number of surface samples from
Surinsar and Mansar lake sites.
C. Sharma & A. Dixit (& M. A. Malik, Jammu)
Project : High altitude plant species response to
global climate change. (Sponsored by G.B. Pant
Institute of Himalayan Environment and
Development Kosi-katarmal, Almora,
Department of Environment, New Delhi, No.
GBPI/IERP/98-99/02/567)
Collected about 200 tree-core samples of Pinus
wallichiana from various sites around Gangotri. The
ring-widths of dated samples were measured. A 410-
year (AD 1590-1999) long chronology has been
prepared. The meteorological data of Shimla station
were correlated with the ring-width chronology. The
study showed that the winter temperature (December-
February) is directly related, whereas June-July
temperature negatively related with the tree growth.
Additional samples of Pinus wallichiana from five
more sites distributed in tree-line zones near
Bhaironghati and Harshil, Uttarkashi were collected
to supplement the previous data for climatic studies.
The samples have been mounted and are being
processed for cross dating and ring width
measurements. The tree core samples of Taxus
baccata, Abies pindrow and A. spectabilis were also
collected from various areas around Yamunotri to
prepare tree-ring data network. Collection of samples
for pollen analyses was also carried out from the
Valley of Flowers, Garhwal Himalaya.
R.R. Yadav, S.K. Bera & J. Singh
Project : Analysis of climatic changes vis a vis glacial
fluctuations using pollen and tree-ring data in
Gangotri glacier area, Garhwal Himalayas.
(Sponsored by DST, New Delhi, No. ES/91/018/
97)
Carried out a field work in and around
Gangotri Glacier area and collected tree ring samples
and subsurface sediments for dendrochronological
and palynological studies. In all 325 tree-cores from
different conifer trees and one broad-leaved taxa were
collected from diversified forests of the region. For
the pollen analysis subsurface sediments were
collected from twelve trial trenches at different
altitudes (9 from Bhujwasa outwash plain and 3 from
Tapoban palaeolake).
Subsurface sediments at different depths of
the sediment profiles have been processed for C-14
dating. So far four samples have been dated from two
profiles. These are 600 +90 yr. BP (at 0.30-0.40 m)
and 1590+200 yr. BP (0.80-0.90 m) of 1.25 m deep
BH/I profile. For the other 1.40 m deep profile, dates
are 5990+120 yr. BP and 8730+170 yr. BP at the
depths of 0.50 to 0.54 m and 1.20 to 1.24 m
respectively. Pollen analysis of one profile has been
completed. This study shows that there are three
climatic phases since around last 2000 years, i.e. cold
and moist climate around 2000 to 1700 yr. BP, warm
and moist 1700 to 850 yr. BP and towards aridity
during 850 yr. BP to recent. Detailed palynological
studies of rest of the profiles are in progress. Besides,
chemical analysis and loss on ignition test for organic
contents and carbonate contents of few profiles were
made. All the tree-core samples were mounted in
wooden frames and polished for analyses. The
counting and dating of the tree rings are in progress.
A. Bhattacharyya, R. Kar & P.S. Ranhotra
38