Annual Report 2011-2012 - Birbal Sahni Institute of Palaeobotany

EBIRBAL SAHNI INSTITUT
1946
OF PALAEOBOTANY
Annual Report 2011-2012
NE of Sarangarh township. The assemblage represents
well-preserved population of both sphaeromorphic and
few acanthomorphic acritarchs along with low amount
of cyanobacterial remains. The recovered acritarchs are
sphaeromorphs (simple & ornamented in nature) followed
by very few acanthomorphs (spinated) belonging to
Spheromorphitae, Netromorphitae, Herkomorphitae and
Acanthomorphitae subgroups. The cyanobacterial
remains represent solitary and colonies of sphaeroidal
cells and unbranched trichomes both septate/aseptate
with/without mucilaginous sheath resembles with the
extant forms belonging to Nematomorphitae subgroup of
cyanobacteria.
Chemically processed shale samples of Charmuria
Formation of Raipur Group, crop out in a nala near Amlipali
village have yielded moderately well-preserved
assemblage of sphaeromorphic acritarchs followed by less
amount of cyanobacterial remains. Dominance of
sphaeromorphic acritarchs particularly the species of
genus Leiosphaeridia in the assemblage suggesting Early
Neoproterozoic age for the fossiliferous unit. Finalized
the study of rich and well-diverse assemblage of organic
walled microfossils comprising 27 genera (16 acritarchs,
10 algae and single VSM) yielded from the heterolithic
shale unit of Chhaporadih Formation of Chandarpur Group
exposed in and around ridges of Dhobinipali villages of
Raigarh district. Assemblage shows dominance of both
sphaeromorphic and acanthomorphic acritarchs followed
by cyanobacterial remains.
Recorded and studied morphologically 10 distinct
type of varied shaped megascopic tapic carbonaceous
film preserved on the shale samples collected from the
Chhuipali Formation of Singhora Group cropout at
Pudapali hill in Raigarh district. The assemblage indicates
a fairly well-preserved biotic realm of multicellular tissue
forming thalli, bilaterial symmetry and erect growth are
the main characteristic features. Morphologically, the
carbonaceous films can be compared with the extant
Phaeophyta, Chlorophyta and Rhodophyta groups of algae.
The fossil assemblage can be compared with known
carbonaceous films of eukaryotic remains known from
the Knob Lake Group, Canada; Michigane and the
Negaunee Iron Formation, Michigan USA; and the
Changcheng Group, China. The studies of recorded
different biotic communities from the fossiliferous units
of the Singhora and Raipur groups and their global
correlation with equivalent sediments shows an
evolutionary trend from Calymmian to Cryogenian age in
ascending order that were evolved and survived in
different complexes of shallow sea.
Rupendra Babu & V.K. Singh
Visited total 24 localities in and around Sarangarh
and adjoining areas of Raigarh district, Chhattisgarh and
Barapahar region of Bargarh district, Odisha for the field
checks and collection of palynological samples (shales,
siltstones and cherts). Collected trace fossils from the
Chhaporadih Formation of Chandarpur Group, lenticular,
nodular black chert and stromatolites from the Saradih
Limestone, and volcanic tuffs from the Churtela Shale of
Raipur Group for the microfossils studies to establish the
biostratigraphy of the Chhattisgarh Supergroup. Also
collected dolerite and thoriferous conglomerate from the
Chandarpur Group.
V.K. Singh
Thrust Area:
FOSSIL LAND PLANT COMMUNITIES: MORPHO-STRUCTURE,
EVOLUTION, SYSTEMATICS WITH APPLICATIONS TO
BIOSTRATIGRAPHY AND PALAEOECOLOGY (Plant evolution, anatomy,
taxonomy and stratigraphy)
Gondwana-Mesozoic Palaeofloristics Group
Project 2.1:
Palaeobotanical investigation of Satpura Gondwana Basin to analyze the floristic
succession, evolutionary perspective, biostratigraphy and palaeoenvironment.
Well-preserved leaf compressions and reproductive
structures of Peltasperm have been studied from Lower
Permian Barakar Formation of Satpura Basin, where they
co-occur with diverse glossopterids. The Indian
peltasperm record is evidence of floristic exchanges
between Laurasia and Gondwana in the Early Permian
involving a dominant group of North American-European
arboreal vegetation of the time. The phytogeographic
10
differentiation, leaf micromorphology and stratigraphic
occurrence of Permian Peltasperms suggest a thermophilic
group appearing in central India during the transition from
humid peat forming to seasonally dry red bed
environments. Therefore, Peltasperms are unlikely
invaders to high-latitude cool-temperate zone postulated
for Early Permian Australindia. Instead their Satpura
occurrence assigns the Indian subcontinent in the
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