108
3 The Microfloral Assemblages—Their Environmental and Climatic …
and close to disappearance of the Striatiti. As the swamps were flooded, the Glossopteris trees were drowned and there is no existence of them until a return to the
swamp environment. The high rainfall/extreme wet was prone to fluctuations and the
Glossopterids return is evident in the Upper Artinskian where they once again make
up a significant contribution to the vegetation.
In the top half of the Upper Artinskian acritarchs peak twice accompanied by lows
in Striatiti and disaccates, both the disaccates and Striatiti disappear entirely during
the peak of acritarchs (Figs. 3.2, 3.3 and 3.4), signifying very high water level and a
lacustrine depositional environment as a result of high rainfall and episodal climate
change.
Biostratigraphic Unit III—The Upper Artinskian: This unit is marked by the
significant fall in numbers of Sulcatisporites to almost its disappearance, and the
marked increase in the Striatiti. Unit III corresponds approximately to Evans’ (1967)
Stage 4 and the Upper part of the Vittatina assemblage of Balme (1964).
The Striatiti are the pollen of the Glossopterids which appeared in Gondwana in
the early Permian and became extinct in the Triassic. The Glossopteris flora was
widespread in Gondwana during the Permian, and fossil plant remains and pollen
were found in Australia, India, Antarctica, South America, South Africa and Madagascar. The most dramatic change of flora more obvious in the Upper Artinskian
is the result of warming from very cold to cold temperate bringing on the explosion in the flora that produced the Striatiti, namely the Glossopteris Flora. The G.
flora diversified to the extent of becoming the predominant vegetation of Gondwana.
The significant number of genera and vast number of species is a testimony to the
abundance of the Glossopterids.
The Glossopterids are generally assigned to the gymnosperms and some favour the
order Gingkoales. The pollen, which is the ultimate generic feature that defines and
distinguishes one plant from another plant (Walker et al. 1968; Guppy et al. 1973),
supports the connection to the gymnosperms. The striate–taeniate feature is unique
to the striatiti and has no match among living gymnosperms. Interestingly, there
are other common features: The venation of leaves of some Glossopteris remains are
strikingly similar to those of Agathis australis, others to Podocarpus elatus. So much
so that if found fossilised leave, Agathis could be easily mistaken for Glossopteris.
The slight warming of Gondwana led to the formation of extensive areas of swamp
which were conditions favouring the Glossopteris plant communities. Fossil root
structure shows the special characteristics that support swamp forests similar to
today’s Taxodium swamp forests.
Although the Striatiti appear in small numbers in the Lower Artinskian, they
come into their own in the Upper Artinskian and dominate the pollen assemblage.
The diversification of fern species continued in the form of many species of zonate
spores. Marsupipollenites is still a distinct contributor to the under story of the swamp
forests. The Glossopteris forests were accompanied by a rich and diverse flora that
included a myriad of ferns, tree ferns, horsetails and cordaitales. These plants formed
the vast and thick coal deposits in the Gondwana Permian Basins.
3 The Microfloral Assemblages—Their Environmental and Climatic …
and close to disappearance of the Striatiti. As the swamps were flooded, the Glossopteris trees were drowned and there is no existence of them until a return to the
swamp environment. The high rainfall/extreme wet was prone to fluctuations and the
Glossopterids return is evident in the Upper Artinskian where they once again make
up a significant contribution to the vegetation.
In the top half of the Upper Artinskian acritarchs peak twice accompanied by lows
in Striatiti and disaccates, both the disaccates and Striatiti disappear entirely during
the peak of acritarchs (Figs. 3.2, 3.3 and 3.4), signifying very high water level and a
lacustrine depositional environment as a result of high rainfall and episodal climate
change.
Biostratigraphic Unit III—The Upper Artinskian: This unit is marked by the
significant fall in numbers of Sulcatisporites to almost its disappearance, and the
marked increase in the Striatiti. Unit III corresponds approximately to Evans’ (1967)
Stage 4 and the Upper part of the Vittatina assemblage of Balme (1964).
The Striatiti are the pollen of the Glossopterids which appeared in Gondwana in
the early Permian and became extinct in the Triassic. The Glossopteris flora was
widespread in Gondwana during the Permian, and fossil plant remains and pollen
were found in Australia, India, Antarctica, South America, South Africa and Madagascar. The most dramatic change of flora more obvious in the Upper Artinskian
is the result of warming from very cold to cold temperate bringing on the explosion in the flora that produced the Striatiti, namely the Glossopteris Flora. The G.
flora diversified to the extent of becoming the predominant vegetation of Gondwana.
The significant number of genera and vast number of species is a testimony to the
abundance of the Glossopterids.
The Glossopterids are generally assigned to the gymnosperms and some favour the
order Gingkoales. The pollen, which is the ultimate generic feature that defines and
distinguishes one plant from another plant (Walker et al. 1968; Guppy et al. 1973),
supports the connection to the gymnosperms. The striate–taeniate feature is unique
to the striatiti and has no match among living gymnosperms. Interestingly, there
are other common features: The venation of leaves of some Glossopteris remains are
strikingly similar to those of Agathis australis, others to Podocarpus elatus. So much
so that if found fossilised leave, Agathis could be easily mistaken for Glossopteris.
The slight warming of Gondwana led to the formation of extensive areas of swamp
which were conditions favouring the Glossopteris plant communities. Fossil root
structure shows the special characteristics that support swamp forests similar to
today’s Taxodium swamp forests.
Although the Striatiti appear in small numbers in the Lower Artinskian, they
come into their own in the Upper Artinskian and dominate the pollen assemblage.
The diversification of fern species continued in the form of many species of zonate
spores. Marsupipollenites is still a distinct contributor to the under story of the swamp
forests. The Glossopteris forests were accompanied by a rich and diverse flora that
included a myriad of ferns, tree ferns, horsetails and cordaitales. These plants formed
the vast and thick coal deposits in the Gondwana Permian Basins.