Insights into the Late Palaeozoic
Gondwana phytogeography
Dr Rajni Tewari
Scientist ‘F’
Birbal Sahni Institute of Palaeosciences, India
G
ondwana - the great southern landmass that formed as a result of the division
of a much larger supercontinent - Pangea (the northern landmass being
Laurasia), consists of the present continents Antarctica, South America, South
Africa, India, New Zealand, Madagascar, Arabia and Australia. The Gondwana
sequence ranges in age from Carboniferous to Early Cretaceous and is primarily a
deposition of non marine sediments comprising conglomerates, shales, sandstones,
coal seams, clay and silt. The base of the sequence is marked by a tillite or glacial
boulder bed. The Gondwana Sequence of India is represented successively by the
Glossopteris, Dicroidium and Ptilophyllum floras which are of Permian, Triassic
and Early Cretaceous ages, respectively. During major part of the Late Palaeozoic,
the Gondwanan terrains occupied same latitudes which were responsible for the
distribution of similar biotas across the southern continents. The Palaeozoic floras
of India include the pre-Gondwana and the Lower Gondwana floras or the Early
Carboniferous and the Glossopteris floras, respectively. The pre-Gondwana flora
comprises the Rhacopteris/Lepidodendropsis flora which is recorded from the
north-west Himalayan region namely, Spiti and Kashmir of the extra peninsular
region and from rest of the Gondwana mainly Brazil, Bolivia, Argentina, South
Africa and Australia. The Glossopteris flora named after the genus Glossopteris - an
iconic fossil leaf of the Gondwanan terrestrial deposits produced by an enigmatic
group of extinct gymnosperms includes Glossopteris and allied leaves together
with different orders of pteridophytic and gymnospermous plant groups and was
responsible for formation of coal, an important renewable energy resource. This
flora was distributed across all the Gondwanan landmasses between 30° and 60°
palaeolatitudes. The flora, is recorded from several conspicuous rectilinear belts of
the peninsular India which include the east- west aligned Damodar-Koel group
of basins, northwest-southeast trending Son- Mahanadi valley and PranhitaGodavari valley basins, the east-west aligned Satpura Basin and the north-south
aligned Rajmahal Basin. Megafloral elements similar to those of Glossopteris flora
of peninsular India are also recorded from the north-east and the north-west
Himalayan regions. The Damodar Basin is considered the standard basin with
respect to the vertical distribution of the Glossopteris flora, as in this basin alone, the
flora is recorded from all the Lower Gondwana horizons. It appears in the Talchir
Formation (Late Asselian to Early Sakmarian), diversifies and develops through the
successive Lower Gondwana horizons namely, Karharbari (Late Sakmarian), Barakar
(Artinskian-Kungurian), Barren Measures/Kulti (Guadalupian), reaches its climax
in the Raniganj and Kamthi (Lopingian) formations and finally extends beyond the
Late Permian to the Early Triassic Panchet Formation where it ultimately perishes.
Distribution of the Glossopteris floral elements through various Lower Gondwana
horizons of India and other Gondwanan countries along with climatic implications
has been analysed in the light of recent researches. The glossopterids first appeared
in the fossil record at about the end of the Carboniferous in West Gondwana, i.e.
South America and South Africa and disappeared from all continents along with
about 90% of the world’s biota during the Permian–Triassic mass extinction event.
During Early Triassic, the Glossopteris flora was replaced by the Dicroidium flora
which was dominated by diversified plant groups such as lycopsids, peltasperms,
corystosperms and conifers. Though, the genus Dicroidium was earlier considered
as a marker taxon of the Triassic, recent records of Late Permian Dicroidium leaves
from Jordan and its fructification Umkomasia from India, suggest a much earlier
origin. Occurrence of megaspores throughout the different horizons of Permian
Gondwana indicates presence of lycopsids, although the macrofloral record of this
group is poor. An emphasis has been given towards quantitative palaeoecological
approaches including megaspore and cuticular studies in investigations of the
Glossopteris flora.
PROFILE
Dr Rajni Tewari is Scientist-F at Birbal Sahni Institute of Palaeosciences, Lucknow, India. She did her B.Sc. in
First Division from Lucknow University (1977), M.Sc. (Botany) in First Division (First position in order of merit)
from Lucknow University (1979), Proficiency in French Language in First Division from Lucknow University
(1981), Ph.D. from Kanpur University (Title: Contribution to the Palaeobotany of Permian Gondwana of India)
(1988) and Professional course in Geology from Lucknow University (1995).
3rd Prof. K. R. SURANGE
MEMORIAL LECTURE
Research experience
Dr Tewari has a research experience of over 36 years. Her research interests are:
 Multidisciplinary research approach to Gondwana Flora of India, Brazil and Antarctica
 Gondwana Megaspores
 Permain Megafossils
 Dispersed Cuticles
 Cuticular studies in palaeo carbon dioxide (pCO2) estimation through stomatal index analysis
 Palaeofire in Gondwanas
Additionally, she has been involved in International collaborative projects with Brazil and US.
Field Experience
Dr Tewari has undertaken several field excursions throughout India such as Damodar, Rajmahal, Son, Wardha,
Krishna-Godavari and South Rewa Gondwana basins, Rajasthan, Nainital, Himalayan region including
Arunachal Pradesh, Darjeeling, Sikkim, Spiti, Kinnaur and Kashmir; and Cerquilho, Quiteria and Curva do
Belvedere, Encruzilhada do Sul and, Mata sandstone of Caturrita/ Santa Maria (early Traissic) Formation of
Afloramento outcrop (fossil wood locality), Saõ Pedro do Sul, RS, Parana Basin, Brazil.
Honours and awards
Merit Certificate for securing First Position in M.Sc., Botany, Lucknow University (1979)
Gold Medal (Dr P.N. Srivastava Gold Medal) for best piece of work, Birbal Sahni Institute of Palaeobotany (2005)
Diamond Jubilee Medal-2008 for high quality publication
Team Medal-2016 for inculcating team spirit in collaborative work within the Institute and with other institutions
Fellow/Member of Professional Scientific Bodies
Member Executive council and Fellow of Palaeontological Society of India; Life Member Indian Association of
Palynostratigraphers; Fellow Palaeobotanical Society of India; Life Member Indian Science Congress; Life Member
International association for Gondwana researches (IAGR); Member International Geological Correlations
Program (IGCP); Fellow Geological Society of India; Member International Society of Plant Morphologists
India; Member IOP; Member IGCP-597
Visits Abroad: France, Germany, China, Brazil, The Netherlands, Russia, Australia, UK, US
Conferences: About 40 National and International Conferences/Symposia/Workshops attended both in India
and abroad
Research Publications: Total number of publications-95
Impact Factor: 55
Editor: Journals Geophytology (2007-2009), The Palaeobotanist (2011- continuing)
Insights into the Late Palaeozoic Gondwana
phytogeography
Dr Rajni Tewari
Scientist ‘F’
Birbal Sahni Institute of Palaeosciences, India
FEBRUARY 3, 2017
1946
Produced by
Publication Unit, Birbal Sahni Institute of Palaeosciences,
53 University Road, Lucknow 226 007, India
Email: [email protected]
BIRBAL SAHNI INSTITUTE OF PALAEOSCIENCES
LUCKNOW
www.bsip.res.in