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GOVERNMENT SCIENCE COLLEGE
JABALPUR
Session 2019 - 2021
PaleoClimate of
Gondwana Supergroup
Presentation by – Nitish Namdeo
M.Sc. Final

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Content
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• Early Climatic Conditions
• At a Glance
• Palynomorphs
• Process of Climate Changes
• Disruption of Zonal Circulation
• Gondwana Monsoon
• Aridity
• Paleocurrents
• Some Climatic Evidences
• References

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Early Climatic Conditions
Carboniferous Ice cap exist in
Gondwana continent at 300 Mya called
Carboniferous Ice Age.
Edward Suess (Austrian Geologist) in
1885 found evidences of Similar
Carbonate belt, Arid Climate Gypsum
Evaporates in Sub-Continents.
Alfred Wegner (1915) in support of his
Continental Drift theory concludedthat
the subcontinents lie on similar
Climatic Belt and were joined together
in cold latitudes surroundingthe South
Pole forming Gondwana Continent.

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• Marine intercalations in Umaria and Manendragarh aid in glacio-marine deposits at the base
of the lower gondwanatermed as Talchir boulder beds primarily form of tillites first recognized
by Blanford in 1856.
• The span of deposition of glacial sediments was from Upper Carboniferous to Early/Middle
Mesozoic (200 My).
• Succeedingconglomerates, sandstones,shales and coal seams of fluviatile and lacustrine
origin are deposited from Upper Carboniferous to Early Cretaceous (Umia Plant beds).
• It was to this sequenceof sediments that H.B. Medlicott in 1862 coined the term ‘Gondwana
System/Super Group’.
• Deposition confined to major river valleys, namely the Koel-Damodar, Son-Mahanadi, Pranhita-
Godavari. Also in places Palar Basin, Nishatbagh Beds and Southern section of Himalaya.
• The lower and upper Gondwana are characterized by the Glossopteris and Ptilophyllum floras
resp. Three fold classification by Hughes, identified a mixed flora called Dicroidium in between
formers.
At a Glance

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• Palynomorphs include both plant and animal fossils that are microscopic in size (from about 5
µm to about 500 µm). Spores and pollen are Examples.
• The preservation potential is the highest in spores and pollen in comparison to other fossils
becausethey are made up of sporopollenin which make it highly resistant to most forms of
decay other than oxidation.
• Climatic variations in terms of temperature and humidity are inferred from the nature of the
palynoflora and this is included next table.
Palynomorphs

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• In Talchir formation it was extremely cold in the Gondwana continent and many of the earlier plants
must have died out, leaving Glossopteris and some spores.
• The formation of rainforest was prominent due to med-high humidity(Climatechange), the heavy
floods began to collapse plants and trees and deposited them in major valleys.
• Two theories of coal deposition are accepted – Insitu theory and Drift theory.
• But slowly denseforest disappeared from India, due to the arid conditions, which began in other
parts of the Gondwana, were felt in India also during the Triassic period.

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• Changes in the position of the continent relative to the South Pole controlled the timing of
Southern hemisphereContinental Glaciation and Consequently, global sea level.
• Gondwana was a large continent, area was greater than 100x106
𝐾𝑚2
. The area of land
exposed during the late Cambrian time of low sea level was about 65x106 𝐾𝑚2.
• So the size and position of the continent would have had two important effects (i) Disruption of
zonal atmospheric circulation. (ii) Establishmentof monsoonal circulation.
Process Of Climate Change

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• Gondwana was positioned with its coastline on the pole
and would have stretched nearly to the equator. This
maximizes the disruption of the zonal circulation.
• The zonal circulation is controlled by the equator to poles
thermal gradient and by the rotation of the Earth.
• The heat exchangebetween equator and poles result in
three surfacewind belts in each hemisphere, the
equatorial/low latitude, mid-latitude, and polar/high
latitude.
• Stretching from pole to equator, Gondwana would have
interrupted the paths of all three wind systems,creating
oceanic subtropical high-pressureand high mid-latitude
low pressureand increasing poleward heat and moisture
transport in the Southern hemisphere.
Disruption of Zonal Circulation

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• Gondwana was large enough to create the strongly
seasonal circulation pattern known as a monsoon.
• Seasonality would have been particularly strong when
the continent was centered in mid-latitudes, rather
than directly over the pole because summerheating is
greater at lower latitudes and winter cooling greater at
higher latitudes.
• At mid-latitudes the continent would have covered
regions of maximum cooling and heating both
temperature and especially precipitation would have
fluctuated strongly with the seasons.
Gondwana Monsoon

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• The large size of the continent also would
have meant that the interior of the continent
was arid (only little precipitation) but climate
would not be uniformly arid over the entire
continent.
• At high altitudes and latitudes where
temperature are cooler and evaporation
rates correspondinglower, the climate may
appear humid ( on evidenceof plants for
example) even though precipitation was
relatively low.
• Conversely, at low altitudes and latitudes,
aridity will be more severewith low rainfall
becausetemperature and evaporation rates
are lower.
Aridity

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• The major direction of flow of the
fluvial systemwas from E to W in
the Koel-Damodar basin and SE
to NW both in the Son-Mahanadi
basin and Pranhita-Godavari
basin.
• The paleo currents study is
based on the dimensionalpebble
fabric of tillites and cross-
beddingdip azimuths of
sandstone.
PalaeoCurrents

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• Only two evidences have been preserved to record the cold phase of the
Talchir glaciation, glacial pavements, and series of exotic boulders.
• The glacial pavement occurs on the right bank of the Penganga River at Irai,
near Chanda, Maharashtra.
• Small patches are also reported from the bank of Ajai River, north of Asansol,
in West Bengal and along the northern fringe of Karanpura basin in
Jharkhand.
• Some of the Gondwana basins contain within them records of climatic
changes indicating periods of deep weathering, physical and chemical, along
with intense ground water activity. These have brought about palaeosols (soil),
which vary in thickness from 4 to 25 m characterised by red brown clay.
Some Climatic Evidences

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• Geology of India Volume 2 – R.Vaidyanadhan, M. Ramakrishnan
• Antarctic Paleobiology – Thomas N. Taylor
• ReseachGate Images
References

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