3 The Microfloral Assemblages—Their Environmental and Climatic …
109
The Upper Artinskian sees the appearance of several spores of probable fern origin; Microbaculispora villosa, Gondisporites raniganjensis, Punctatisporites fungosus, Punctatisporites cf. Lalmatiasporites. Gondisporites raniganjensis has been
considered a marker spore for the Late Permian in other Gondwana Basins (Banerjee
and D’Rozario 1990; Tripathi et al. 2012).
Unit IV—Upper Permian: This sub-division marks the uppermost part of the
Permian system in the present study. The Striatiti are still a dominant component of
the microfloral assemblage, and in many samples make up over 50% of the total pollen
count. A group of ‘new’ spores make their appearance. These are: Kraeuselisporites,
Bascanisporites, Granulatisporites, Densoisporites, Anapiculatisporites and Dulhuntyispora dulhunty. A few appear right at the top of the uppermost part of Unit IV;
these are Punctatisporites fungosus and Culleisporites. Many plants do not make it
beyond the Artinskian as can be seen from their individual pollen/spore distribution
charts in Appendix (A.1 and A.2).
The present unit IV corresponds to Balme’s (1964) Dulhuntyispora assemblage
and to Evans’ (1967) ‘Stage 5’. This zone is still dominated by the Glossopteris flora
and the swamp-type environment. Water levels have changed over the time span of
the Upper Permian as can be seen from the overall negative correlation between the
Striatiti and acritarch peaks (see pollen distribution charts for bore A and bore C).
Highs in acritarchs correspond to lows in the Striatiti/Glossopterids counts. Water
bodies over a large area were formed, which encouraged algae to flourish and replace
the swamp vegetation of the Glossopterids for a while. A prominent peak of acritarchs
is seen in the uppermost part of the Upper Permian, also corresponding to a low of
Striatiti.
The alternating times of change between flooding and swamp as expressed by the
pollen mark a change in the depositional environment following an episodal climatic
change that brought on high rainfall resulting in flooding of the swamps, rise in water
level, drowning of the swamp forests and algal dominance.
Similar results were reported by Wetering et al. (2013) from their study using
δ
13 C/
12 C of coal lithotypes alongside floral assemblages from the Upper Permian of
the Bowen Basin. Their study highlighted the interaction between wet and drying-out
and their effect on the Glossopteris flora. The same study demonstrated the climatic
fluctuations over time.
δ
13 C/
12 C study of Permian coal measures ranging in age from Sakmarian to Uppermost Permian from South India by Singh et al. (2012) and Aggarval et al. (2019)
reported a correlation between C-isotope composition and extreme climatic events.
The samples analysed by their study differentiated between lithologies (not lithotypes) in general and obtained very similar results to those reported by Wetering
et al. as would be expected from same kind of vegetation. The fluctuations in isotopic composition evident in both studies has been attributed by the authors to fluctuations in the climate. The extremely isotopically ‘heavy’ values obtained by both
studies in some of the samples is most probably the result of extensive flooding and
algal dominance contributing to the organic matter (Glikson 1984). The conclusion
reached by both studies demonstrated indirectly the climatic effect overriding the
general vegetational influence. Strongly isotopically negative values, on the other
109
The Upper Artinskian sees the appearance of several spores of probable fern origin; Microbaculispora villosa, Gondisporites raniganjensis, Punctatisporites fungosus, Punctatisporites cf. Lalmatiasporites. Gondisporites raniganjensis has been
considered a marker spore for the Late Permian in other Gondwana Basins (Banerjee
and D’Rozario 1990; Tripathi et al. 2012).
Unit IV—Upper Permian: This sub-division marks the uppermost part of the
Permian system in the present study. The Striatiti are still a dominant component of
the microfloral assemblage, and in many samples make up over 50% of the total pollen
count. A group of ‘new’ spores make their appearance. These are: Kraeuselisporites,
Bascanisporites, Granulatisporites, Densoisporites, Anapiculatisporites and Dulhuntyispora dulhunty. A few appear right at the top of the uppermost part of Unit IV;
these are Punctatisporites fungosus and Culleisporites. Many plants do not make it
beyond the Artinskian as can be seen from their individual pollen/spore distribution
charts in Appendix (A.1 and A.2).
The present unit IV corresponds to Balme’s (1964) Dulhuntyispora assemblage
and to Evans’ (1967) ‘Stage 5’. This zone is still dominated by the Glossopteris flora
and the swamp-type environment. Water levels have changed over the time span of
the Upper Permian as can be seen from the overall negative correlation between the
Striatiti and acritarch peaks (see pollen distribution charts for bore A and bore C).
Highs in acritarchs correspond to lows in the Striatiti/Glossopterids counts. Water
bodies over a large area were formed, which encouraged algae to flourish and replace
the swamp vegetation of the Glossopterids for a while. A prominent peak of acritarchs
is seen in the uppermost part of the Upper Permian, also corresponding to a low of
Striatiti.
The alternating times of change between flooding and swamp as expressed by the
pollen mark a change in the depositional environment following an episodal climatic
change that brought on high rainfall resulting in flooding of the swamps, rise in water
level, drowning of the swamp forests and algal dominance.
Similar results were reported by Wetering et al. (2013) from their study using
δ
13 C/
12 C of coal lithotypes alongside floral assemblages from the Upper Permian of
the Bowen Basin. Their study highlighted the interaction between wet and drying-out
and their effect on the Glossopteris flora. The same study demonstrated the climatic
fluctuations over time.
δ
13 C/
12 C study of Permian coal measures ranging in age from Sakmarian to Uppermost Permian from South India by Singh et al. (2012) and Aggarval et al. (2019)
reported a correlation between C-isotope composition and extreme climatic events.
The samples analysed by their study differentiated between lithologies (not lithotypes) in general and obtained very similar results to those reported by Wetering
et al. as would be expected from same kind of vegetation. The fluctuations in isotopic composition evident in both studies has been attributed by the authors to fluctuations in the climate. The extremely isotopically ‘heavy’ values obtained by both
studies in some of the samples is most probably the result of extensive flooding and
algal dominance contributing to the organic matter (Glikson 1984). The conclusion
reached by both studies demonstrated indirectly the climatic effect overriding the
general vegetational influence. Strongly isotopically negative values, on the other