Annual Report 2011-2012 - Birbal Sahni Institute of Palaeobotany

EBIRBAL SAHNI INSTITUT
Annual Report 2011-2012
1946
OF PALAEOBOTANY
undertaken in South Andaman Island, Little Andaman
Island, Havelock and Neil Islands. In South Andaman, in
and around Port Blair region, samples are collected from
Wadoor, Chidyatapu, Ross Island and South Point. All
the outcrops are measured and the samples are collected
systematically at close intervals. In Little Andaman Island
(Hut Bay), four outcrops are studied and collected samples
Project 7.1:
Organic Petrology Group
from the measured sections. In Havelock and Neil Islands
numbers of outcrops are studied in different cliff sections
and samples are collected at very close intervals. Latitudes
and longitudes of all sampling locations are observed and
noted.
A.K. Ghosh, Abhijit Mazumder & Pawan Govil
Biopetrological investigations on the coals of Wardha-Godavari coalfields in relation
to coal bed methane
Carried out coal petrographic (maceral &
reflectance) research work, regarding the constitution and
rank of 10 coal seams representing Bhupalpalli area of
the Godavari Valley Coalfield. The coal samples collected
between 106.18 and 300.35 m depth range in bore-hole
No. 618 represents nine coal seams. However, samples
of only one coal seam, i.e. Seam No. 5, intersected
between depth range 415.65 and 416.45 m, have been
collected from bore-hole No. 616. Different seams of
this area contain alternate coal bands characterized by
vitrinite or inertinite rich constitution. Vitrinite reflectance
value (R o mean
%) range of the coals in this region ranges
from 0.49% to 0.67%. In general, these coals have attained
high volatile bituminous C rank. Thus, the depositional
site has experienced alternate oxic and anoxic moor
condition.
O.S. Sarate
Project 7.3:
Organic petrological and geochemical characterization of South Indian lignite deposits
Organic petrological data collected from mine I
section of Neyveli lignite have been further studied under
normal light in order to depict the distinctive pattern of
varied microconstituents in time and space. The study
has shown that huminite maceral was predominantly
occurring in the section studied. This provides the clue
that these lignites could be best used for the extraction of
humic acids. Liptinites chiefly constitute spores, pollens,
cutinite, suberinite, resins, liptodetrinite also occur in
appreciable amount. Alginites are also recorded from
these lignites. Inertinites representing the fusinite,
semifusinite, and funginite are also noticed in Mine I
section. Huminite versus inertinite maceral distribution
suggest the fluctuating oxidative and reductive conditions
in the evolution of Neyveli swamp. Pyrites/marcasites
which cause the mining problem in the area are recorded
in these lignites. The fromboidal characteristics of pyrites
recorded from these lignites show the prevalence of euxinic
conditions during the development of these seams in the
swamp.
Rakesh Saxena
Project 7.4:
Organic matter characterization of lignite-bearing successions of western India
Documented the petrological data of lower Tertiary
lignites from Vastan mine (Surat district, Gujarat). These
lignites, belonging to the Lower and Upper seams, are
found to be rich in huminite macerals (average 57%)
followed by liptinites (av. 26%) and inertinites (av. 6%)
along with low to moderately high associated mineral
matters (av. 11%). Liptodetrinite (av. 12%) and resinite
(av. 8%) are the dominant macerals of liptinite group in
these lignites. The inertinite group is represented by
funginite and semifusinite/ fusinite. Predominance of
huminite in general indicates the wood dominated ancient
vegetation as the main source for the formation of Vastan
lignites. Higher amount of detrohuminite (av. 34%) in
lignites, otherwise indicative of tree-less swamps, suggests
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the contribution of herbaceous and pteridophytic plants
growing profusely in the dense angiospermic forests. The
composition of macerals indicates the deposition of lignite
in sub-aqueous condition in wet-reducing environment
with intermittent exposure and subsidence of the peat
surface. High detrital fractions (detrohuminite and
liptodetrinite) and low tissue preservation index suggest
high biological and bacterial degradation of ancient peat
and elevated pH conditions of swamp. The rank of the
lignites, determined through reflectance measurement (R r
: 0.24-0.35%), indicate that the Vastan lignite is less
mean
mature and fall in the early diagenetic zone of methane
generation.
Alpana Singh & B.D. Singh
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