1995-96 - Birbal Sahni Institute of Palaeobotany

1995-96
Quercus, Carpinus,
etc. are lowly represented, reflecting ± surrounding vegetation.
Chhaya Shanna
Pollen analysis of '15m deep lacustrine profile from Sat Tal (ST -II), Garhwal
Himalaya has shown that the vegetational sequence commences with mixed conifer-broadleaved
forest. The conifers such as Pinus, Cedrus, Abies, Picea together with Quercus,
A/nus, Belu/a, Carpinus, etc. were chief constituents of these forests. The overall picture
emerged out indicates the cold-temperate climate in the region. Subsequently, the improvement
in the frequencies of the broad-leaved taxa such as Quercus, A/nus Belu/a, Carpinus
and corresponding decline in conifers reflect the amelioration of the climate. Thereafter, the
improvcment in the conifers, particularly Pinus and Abies, and decline in broad-leaved
taxa, indicate the restoration of mixed conifer broad-leaved forest in the region. Photography
of the fossil palynomorphs recovered from the profile was also carried out.
Five soil profile samples from Chharkha Tal, Murdhung Tal, Hunia and Seni
Swamp (Uttar Kashi) were collccted for pollen analytical investigations. A dctailed survcy
of forest floristics of the region was also conducted and two dozcn surface samples were
also collected to analyse the relationship betwecn the present and past vegetation.
Chhaya Sharma & M.S. Chauhan
Pollen analysis of partly investigated sedimentary profile (8 samples) from subalpine
Kupup Lake from eastern Himalaya has revealed the dominance of non-arboreals
overarboreals. Quercus is dominant alongwith other associated arboreal taxa, viz., Alnus,
Belu/a, Carpinus, Jug/am, Rhododendron, CorY/liS, Pinus, Twga, etc. reprcsented in low
values. Non-arboreals arc rcpresented by elements of Cyperaccae, Poaceae, Cerealiatype,
Apiaceae, Cheno/Ams, Ranunculaceae, Asteraceac, etc.
Re-investigated 6 profile samples from Deoria Tal-III, Garhwal Himalaya. Constructed
pollen diagranl of carlier cumpleted 1.5 m deep profilc and prcpared draft of the
paper cntitled "Vegetation and climate of Garhwal Himalaya during Early Holocene".
Studies reveal that around 7,000 years B.P., Oak mixed broad-leaved forests cxisted in the
region, reflecting wann temperate and humid climate. Subsequently, around 4,000 yrs B.P.
decline in Oak as well as its other broad-Ieavcd associates is registered with a corrcsponding
risc in grasses, sedges, etc. and this leads to infer a changc in the climate to cooler conditions.
Anthropogenic activities are noticed during this period as cvidenced by thc tirst
appearance of Cerealia-type pollen besides othcr cncountered culture pollen. Thereafter,
around 2,000 years B.P. restoration of Oak forests took place indicating the amelioration in
the climatic conditions.
Chhaya Shanna & Asha Gupta
Finalised thc joint palaeoclimatic work carried out from Spiti Valley with collaboration
of Wadia Institute of Himalayan Geology, Dehradun. 11,e study has revealed that
during 2000 to 1500 yrs B.P. this region had alpine-steppe, constituted of grasses, sedges,
Cheno/Ams, Artemisia together with scrubby elements of Juniperus, "-phedra, etc. The
vegetational assemblage denotcs that tillS region was undcr tl,e Impact of cold and dry
117