1994-95 - Birbal Sahni Institute of Palaeobotany

BSIP
vegetation during the last 60 million years. The quest for understanding the origin and
diversification of flowering plants is one of the important areas of research iR palaeobotany.
During the year attempts were continued to study the varied types of fossil pollen
which belong to flowering plants. The study of subsurface sediments near Kapurdi and
Jalipa near Barmer, Rajasthan reveals striking resemblance with Matanomadh Formation
of Kutch in its pollen content. A Palaeocene-Eocene age (about 55 million years back) has
been suggested for this pollen flora. This assemblage indicates a low-land, fresh-water
swamp-type environment of deposition, with water edge and coastal elements.
In order to build up the model of vegetational changes through time, sequence of
rocks are analysed for the types of pollen found in them. Such a study was conducted from
Kalakot area, Jammu where three characteristic zones of pollen assemblage have been identified
which are correlated with those described from Kalka-Simla and Banethi-Bagthan
area of Himachal Pradesh. The composition of spores, pollen and other plant microfossils
reveals a shallow marine environment of deposition for the sediments of Subathu Formation.
Well-preserved flowers are rarely found as fossils. The search of such fossils from
the Palaeocene (55-65 million years old) sediments of Barmer, Rajasthan and Makum
Coalfield, Assam has resulted in the finding of spike-like male flowers of Nipa palm. This
has a bearing on the past distribution of paJrns on the Indian Peninsula.
Pollen analysis of sedimentary core from Berijam Lake, Palni Hills, Tamil Nadu
has revealed three vegetational stages. Phase I (20,000 to 16,000 years before present)
records the existence of grassland; Phase II (16,000 to 4,000 years before present) reveals
the appearance of herbaceous plants associated with Shola forest, with decrcase in grasses
and amelioration of climate to warm and humid; Phase 111(4,000 years before present till
date) indicates increasing cold and decreasing humid climatic regime.
Similar studies on fossil pollen recovered in the bore-core from Sadanand area,
Mahanadi delta, Orissa have deciphered the occurrence of distinct transgression and regression
of sea at 40,000 years before present in this region. The age of these events has
been determined by the C-14 method at the Carbon-dating laboratory of the Institute.
Distribution of plant fossils and geography of the past
During the remote past, the Himalayan region of the present time was occupied by
a sea - named as Tethys. The plant fossils found in the Tethyan Himalaya relate the story
of floral affinity with mainland Indian Peninsula 00 one hand and the Middle East-Angara­
China on the other. Relationship of floras also reflects the geographic positions of various
regions during the geol(Jgical past.
There are several programmes in which the sediments of Himalaya are investigated
for plant fossils. Some of such studies undertaken during the year have revealed that the
spore and pollen flora from Niti, Spiti and Kashmir Himalaya had a close affinity with the
floras of Gondwana during Permian and Triassic time, i.e., about 220-270 million years
back.
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