Organisational Structure - Birbal Sahni Institute of Palaeobotany

Birbal Sahni Institute of Palaeobotany
Project 9: Marine micropalaeontology of petroliferous basins
Component 1: Calcareous skeletal algae from the Tertiary sequences of Meghalaya and Kutch basins
Taxonomic study of coralline algae from thin
sections of Tertiary (Oligocene and Miocene)
limestone samples of Kachchh Basin was carried out.
Late Oligocene (Chattian) coralline algae have been
recorded from the topmost member (Bermoti
Member) of Maniyara Fort Formation exposed in the
Bermoti stream in a locality about 0.5 km SE of
Bermoti village and also in the stream near village
Bernani. The Chattian algal assemblage comprises
species of Lithophyllum and Mesophyllum. Late
Lower Miocene (Burdigalian) coralline algae have
been recorded from the Chhasara Formation exposed
along the Khari Nadi near the village Chhasara. The
Burdigalian algal flora is represented only by species
of Corallina. Interpretation has been made on the role
of calcareous algae especially in evaluating
palaeoecology and palaeobathymetry. The
environment of deposition of Maniyara Fort
Formation was marginal marine, littoral to shallow
inner-shelf. Marine trangressive environment shifted
from lagoon to medium - high-energy open shelf
environment when coral bioherms were formed.
Attempts have been made to provide information on
the depth distribution of coralline incrusting
associations and from the Oligocene of southwestern
Kachchh. In addition a conceptual model of mediumenergy
reef formation has been proposed on the basis
of Late Oligocene (Chattian) algal forms. Taxonomic
study on the coralline algae from Tertiary (Paleocene)
sediments of Meghalaya have also been done on the
samples of Lakadong Limestone Member, collected
from K.L.M.C Limestone quarry, near Bholaganj
(about 0.5 km west of western bank of Um
Sohryngkew River). The coralline algal flora
comprises species of Lithoporella, Sporolithon,
Phymatolithon, Lithophyllum and Mesophyllum.
A.K. Ghosh
Component 2: Integrated phytoplankton biozonation and palynofacies analysis of Cretaceous-Tertiary
sequences of Meghalaya and Kutch with emphasis on bioevents, time boundaries and
palaeoenvironment
Dinoflagellate cyst bioevents identified in the
upper Cretaceous-Palaeocene succession of the Khasi
Hills (Meghalaya) are summarized. Detailed
morphotaxonomical studies on some dinoflagellate
cysts belonging to Apectodinium are carried out.
These are characterized by a broader than long cyst
lacking apical horn, reduced or absent antapical horns
and broad lateral horns. These cysts differ from
known Apectodinium species in overall shape and
horn characteristics and are considered to represent
a new species of the genus. LM/SEM investigation
of selected samples from the Lakadong Sandstone to
study preservational status of dinoflagellate cysts/
organic matter in relation to the fluctuating anoxic
bottom conditions indicated by Apectodinium-rich
assemblage is carried out. Evidences of bacterial
decay and pyrite-relic structures are noted on the
dinocyst walls and terrestrial organic matter.
Palynofacies investigations of the lower part of the
Mahadeo Formation (Therriaghat area) revealed
significant variations in the vertical distribution of
dinocysts and land-derived organic matter (marine/
terrestrial component). Stratigraphic levels with high
terrestrial component in the basal part of the
succession are found to contain dinocysts in
moderate/low numbers and reworked Permian
palynomorphs. These are interspersed with levels rich
in dinocyst assemblages (dominated by chorate cysts).
Occurrence of Xenascus ceratoides in this assemblage
is significant as its LAD indicates Lower/Upper
Maastrichtian boundary.
R. Garg, Khowaja-Ateequzzaman & V. Prasad
Recorded additional marker nannofossil taxa
from the Langpar Formation (Danian) to update agesignificant
bioevents in the Upper Cretaceous-
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