Annual Report 2011-2012 - Birbal Sahni Institute of Palaeobotany

EBIRBAL SAHNI INSTITUT
Annual Report 2011-2012
1946
OF PALAEOBOTANY
Gondwana during the deglacial phase of Late
Carboniferous-Early Permian glaciation.
Anjum Farooqui & Neerja Jha
Pollen analysis of honey sample collected from
Lucknow University campus has shown a good
assemblage of pollen. Among the pollen taxa, P. spicigera
(29%), Prosopis juliflora (20.8%), Syzygium cumini
(25%), their Eucalyptus sp. (10%) the major source of
nectar as marked by frequent presence of their pollen.
The overall assemblage shows that these plants were in
full bloom during the course of honey production and the
honey is of multi-floral nature. Bombax ceiba (7%),
Ailanthus excelsa and Dodonea, Tinospora cordifolia,
etc. were the minor sources of nectar and bee forage as
depicted by relatively low frequencies.
M.S. Chauhan & Anjali Trivedi
Texture, mineralogy, geochemistry, palynology and
magnetic susceptibility study of a 2 m deep sediment core
from Padauna Swamp (Amarkantak), Anuppur district
(MP) infer that between 8,620 and 7,566 yrs BP a cool
and dry climate prevailed with open tree-savannah type
vegetation dominated by grasses and followed by sedges,
Artemisia and members of Chenopodiaceae/
Amaranthaceae with sprinkle of trees viz., Schrebera,
Aegle marmelos, Sterculia urens, etc. and thickets of
Fabaceae, Acanthaceae and Oleaceae. This is well
supported by lower organic over carbonate carbon
concentration, coarser texture having relatively low CIA
values and presence of some primary mineral in the
sediments. Warm and humid climate followed between
7,566 and 6,250 yrs BP. The tree-savannahs were
succeeded by open mixed deciduous forests with the
invasion of a few more trees, Madhuca indica,
Holoptelea, Emblica officinalis, Mitragyna, members
of Anacardiaceae, etc. A considerable rise in organic
carbon generated from the degradation of plentiful
biomass along with increase in clay content with signs of
kaolinite and increase in immobile over mobile elements
with slightly higher CIA values also suggest climatic
amelioration.
The presence of ruderal plants such as Artemisia,
Urticaceae cf. Cannabis sativa, ChenoAm, etc. further
infers initiation of human activities in the region. Between
6,250 and 2,800 yrs BP, the mixed deciduous forests
became more diverse and dense, subduing the extension
of grasses and other herbaceous elements. Sporadic
incursion of Shorea robusta (Sal) in forest floristics was
recorded around 5,000 yrs BP. The overall change in the
vegetation mosaic reflects that a warm and more-humid
climate prevailed in the region, probably on account of
invigoration of southwest monsoon. This observation is
further corroborated by other proxy data showing a spurt
in organic/inorganic carbon ratio, increase in clay content
with matured mineralogy, significantly higher CIA and
magnetic susceptibility values. Since 2,800 yrs BP
onwards, the modern Sal dominated deciduous forests
got established indicating continuation of warm and humid
climate including timely arrival of SW monsoon.
M.S. Chauhan, Anupam Sharma, Binita Phartiyal &
Kamlesh Kumar
A 2 m sedimentary soil profile from Singrimari
Swamp dated back to 11,000 yrs BP has documented
three climatic phases as inferred from pollen and nonpollen
evidence. Manuscript prepared on the aspect.
S.K. Basumatary & S.K. Bera
Melissopalynological investigation of 10 samples
from Almora district, Uttarakhand shows that the majority
of honey samples are bifloral. Study further shows that
honeybee preferred Salmalia malabaricum for foraging
in summer and Brassica campestris in winter honey
samples attaining at the highest value of 71.23% and
73.97% respectively. Manuscript on the aspect has been
finalized.
Swati Dixit, S.K. Basumatary, Hukam Singh & S.K. Bera
Palynological observation of one 3.4 m deep
sedimentary profile cored from Chayagaon swamp,
Kamrup district, Assam has revealed climate vis-à-vis
vegetation succession since Late Quaternary supported
by contemporary pollen/vegetation relationship in and
around the swamp which could be employed as
background information for the palaeoclimate studies.
Steady occurrence of Cereal pollen species (Poaceae)
during 12,450 cal yrs BP is indicative of initiation of
pastoral activity since the early Holocene. After 989 cal
yrs BP, an alarming change in pollen assemblages,
indicating a decrease in sal and its associates namely
Lagerstroemia, Lannea, Terminalia, Syzygium and
Salmalia, with a sharp increase in Melastoma, Ziziphus
and Areca catechu was occurred. The infestation of major
ruderal elements like Chenopodiaceae, Artemisia,
Plantago, Tubuliflorae, and Brassicaceae with cereals
hints for forest clearance with large scale farming and
anthropogenic soil erosion.
Swati Dixit & S.K. Bera
A manuscript entitled ‘Modern vegetational
distribution and pollen dispersal study within Gangotri
glacier valley, Garhwal Himalaya’ has been prepared.
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