Annual Report 2011-2012 - Birbal Sahni Institute of Palaeobotany

EBIRBAL SAHNI INSTITUT
1946
OF PALAEOBOTANY
Annual Report 2011-2012
of grass subfamily Ehrhartoideae. The new Oryzeae
fossils from India suggest substantial diversification within
Ehrhartoideae by the late Cretaceous, pushing back the
time of origin of Poaceae and changed the perspective
on early diversification in angiosperm as a whole. These
results, therefore, necessitate a re-evaluation of current
models for grass evolution and palaeobiogeography. This
discovery not only pushes the clock back on the evolution
of rice crop but also that India could be the place of its
origin more than 65 million years ago.
Vandana Prasad [& C.A.E. Strömberg, A.D. Leaché, B.
Samant, R. Patnaik,
L. Tang, D.M. Mohabey, S. Ge5 & A. Sahni
(multi-institutional)]
The samples from Ruata Quarry, Turial Bungalow
Section and Turial Prayer Point Section representing
Bhuban Formation (in Mizoram) have yielded datable
nannofossil assemblages. Though the Bhuban Formation
is broadly mega and micro-fossil lacking thick calcareous
sandstone unit and its precise age has been debated for
want of fossils. The Ruata Quarry R1 sample is dated
NN2 - NN4 Late Burdigalian-Early Langhian of Early-
Middle Miocene, whereas R3 number sample is NN11B
Messinian i.e. Late late Miocene in age. The Turial
Bungalow Section has two productive levels represented
by TB3 which is dated NN1 - NN6 Early Aquitanianian-
Early Serravalian of Middle Miocene age and the TB2
sample is dated NN11B – NN12 Messinain/ latest
Tortonian of Miocene/ Pliocene age. Very close sampling
at the boundary in this section of Mizoram is required to
be done to resolve and calibrate the Mio-Pliocene
boundary globally. Only one sample TP3 from Turial
Prayed Point section has been dated NN11B of Latest
Miocene age.
Jyotsana Rai [& R.P. Tiwari (Mizoram University, Aizawl)]
A manuscript entitled ‘Calcareous nannofossils
from the Ottakoil Formation, Cauvery Basin, South India:
Implications on age and late Cretaceous environmental
conditions’ has been finalized.
Jyotsana Rai [& Mu. RamKumar, T. Sugantha &
K. Anbarasu (Periyar University, Salem)]
Moderately diversified with low frequency
nannofossil assemblage comprising over 20 species are
recorded from one (S-13) calcareous marl sample of
Ariyalur Formation from Cauvery Basin, situated north
of the village Aladi exposed on either side of the
road displaying friable limestone beds in a stream section
bearing Lat : N11°37’47"; Long: E79°21’4". The
recovered nannofossil taxa are of latest Maastrichtian in
age. On the basis of the occurrence of zonal marker taxa
Micula prinsii the assemblage is assigned to CC 26b
(Perch- Nielsen, 1985) corresponding with UC 20d TP of
Burnett in Bown (1998) of latest Maastrichtian age. It is
a low latitude marker and is indicative of latest
Maastrichtian age approximately 50,000 years prior to
the K/T boundary. Besides this, frequent abundance of
Petrobrasiella bownii in both very small and big sizes
(3-4 µm to 10 µm diameter) along-with Ceratolithoides
kamptneri, Arkhangelskiella maastrichtiana,
Calculites obscurus attests to this zonal placement. A
high latitude Maastrichtian age genus Nephrolithus
represented by N. miniporus is also present in the
assemblage indicating presence of cold water current in
Southeastern part of India during latest Maastrichtian
time. Reworked Campanian age forms are represented
by Ceratolithoides aculeus, Nannoconnus spp. and
Haqius circumradiatus are also present in the
assemblage. The detailed study may provide exact K/T
boundary level as Pondicherry Formation of Palaeocene
age is exposed in the vicinity.
Jyotsana Rai & Abha [& Malarkodi
(Bangalore University, Bengaluru)]
The recovered palynofloral assemblage from the
Inglis Formation at Kalapathar of Havelock Island,
Andaman Sea, is mainly composed of angiosperm and
gymnosperm pollen, pteridophytic spores, fungal spores
and ascostromata. Algal zygospores and diatoms have
also been recorded in abundance. Some of the important
constituents of the palynofloral assemblage are
Polypodiisporites spp., Pinuspollenites spp,
Malvacearumpollis spp., and Compositoipollenites sp.
Sponge spicules are predominant in most of the samples.
The diatom assemblage is represented by Diplones sp.,
Biddulphia spp., Coscinodiscus spp. and Mastogolia
spp. Palynofloral composition suggest an Early Miocene
age to the assemblage. The palynoflora has been
compared with modern equivalents and it indicates a
subtropical humid climate with high degree of rainfall
during the deposition of the sequence in the area of
investigation. A paper on the aspect is finalized.
Samir Sarkar (& Bhagyapati Devi (Manipur University)]
Carried out palynological investigations of the
Siwalik sediments of Tanakpur and Nainital and its
adjoining areas of Uttarakhand, and recovered rich
palynofloral assemblages from several sections of Lower
and Middle Siwalik sediments. The palynoflora indicates
a tropical-subtropical, warm-humid climate with heavy
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