Organisational Structure - Birbal Sahni Institute of Palaeobotany

Birbal Sahni Institute of Palaeobotany
Pyrite framboids occurring on degraded leaf
cuticles were observed under SEM and EDAX
systems (with U. Bajpai). The investigations from
Late Tertiary sediments of Mahuadanr valley, Palamu
indicate that framboidal pyrites are formed in the
cavities and cell lumens of degraded leaves and other
plant entities under reducing conditions and are the
result of the activity of mainly sulphate reducing
bacteria. Pyrite framboids occur in clusters and as
solitary spherules. The elemental analysis and organic
matter substrate of framboids indicate that the C, Fe
and S are the main constituents. However, N and O
are also present in sufficient quantity. The
morphological characters of bacterial colonies are
generally retained during mineral uptake to form
framboids. Srivastava and Shukla visited Neyveli
lignite field, Cuddalore district, Tamil Nadu and
collected lignite samples, leaf compressions, lignified
woods and resin lumps from different mines.
Microbial action on dispersed and compressed
leaf cuticles from clay, shale and carbonaceous shale
of various geological periods (Early Carboniferous-
Kotshu Hills, J&K; Permian- Lohapity, Jharia
coalfield; Late Triassic-Janar and Haral villages,
South Rewa Basin; Early Cretaceous- Sehora,
Jabalpur, and Naicolam, Trichurapalli; Tertiary-
Bihpuria well #1, Upper Assam; Miocene-
Amberiwadi, Maharashtra; Pliocene to Pleistocene-
Mahuadanr valley, Palamu, Bihar) have been studied
under LM, SEM and TEM (with U. Bajpai and N.
Prakash). It has been observed that most of the leaves
or leaf fragments start undergoing various
degradational processes, as soon as they are detached
from the parent plant body. The pathogen (fungi and
bacteria) enters the leaf tissue through stomata, pore
or cracks and first degrades non-lignified components
present between cuticular layers and then the other
parts. These fungi and bacteria rapidly colonize the
plant fragments including leaf litter when buried
under the sediments. The observations under SEM
and TEM shows three characteristic stages of
degradation of leaf cuticles affected by fungal
attack— hyphal invasion, penetration and dissolution
of tissues. In case of bacteria infestation, corrosion,
cavity formation and tunneling represent various
degradational phases. These processes ultimately
contribute towards the formation of amorphous
organic matter types.
Anand-Prakash, G.P. Srivastava, M. Shukla &
M. Kumar
Component 2: Biopetrographic evaluation, genesis and depositional history of Indian coals
(I) Organic petrological evaluation of Karanpura coal deposit (Damodar Basin) in relation to carbonization
properties, genesis and depositional history
Studied microconstituents (macerals and
microlithotypes) of coals from Kargali Seam of
Kathara colliery to assess the nature and composition
of coals. The coals belong to Early Permian Barakar
Formation of East Bokaro coalfield. In general, these
coals are found to be rich in vitrinite group (38-74%,
vitric and fusovitric coal types) followed by inertinite
and liptinite groups. Likewise, their vitrite, clarite,
vitrinertite and duroclarite microlithotypes are high.
The rank values (R o max
0.82 - 0.94%) determined
through reflectance measurements on maceral
vitrinite indicate that the coals have attained highvolatile
bituminous A stage. On the basis of coal
types, it appears that the Kargali Seam originated
dominantly from woody vegetation under anaerobic
(wet-reducing) condition with occasional aerobic
(dry-oxidative) conditions. The rank and composition
of coals indicate that these coals are within the
threshold of methane (thermogenic) generation.
B.K. Misra & B.D. Singh
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