Chapter 3
The Microfloral Assemblages—Their
Environmental and Climatic
Interpretation
The questions arising from the systematic work of this study are: What do the pollen
and spores tell us? How significant are the sometime subtle changes in pollen/spore
assemblages? Is the composition of the spore/pollen assemblage indicative of environmental and atmospheric conditions? In order to answer these questions and reconstruct their environment, there is a need to organise the plant remains, namely the
pollen, spores and acritarchs into some grouping with common characteristics. These
are: appearing together in same stratigraphic level; sharing morphological features;
abundance in a lithological unit with specific petrology; prevalence of one type of
pollen, spore or acritarch.
On the basis of the above, the microfloral assemblages are grouped into four
biostratigraphic units (Figs. 3.2, 3.4, A.1):
Biostratigraphic Unit I is characterised by the following pollen: Parasaccites gondwanensis, Microbaculispora tentula and Punctatisporites gretensis. These
pollen comprise the oldest assemblage isolated and described from the Permian
sequence of the Collie samples, and may be referred to as the Parasaccites Zone.
This unit is present in all bore hole samples of Collie, Wilga Basins, Muja sub-basin
and Sue No. 1 bore. The lithology that this assemblage shares is tillites, which are
glacial deposits and contain the earliest Permian vegetation following the retreating
glaciers. This assemblage is poor in types of pollen on the generic level; the main
components of the microflora being the three pollen mentioned above. The ratios
between the three forms vary slightly from one sample to another. Nevertheless,
they comprise 80–90% of the total microflora of the Parasaccites zone. Parasaccites and Punctatisporites gretensis dominate this assemblage, although there are
bisaccate forms present, namely Potoniesporites neglectus and Illinites tectus. The
spores of the monolete Cycadopites cymbatus and the trilete Microbaculispora tentula accompany the assemblage. All these pollen except Illinites do not have any
significant presence beyond the Sakmarian. Illinites continues to be present in the
Artinskian Biostratigraphic Unit II.
Towards the end of the Sakmarian a change to less harsh climatic conditions
enabled a group of new plants to establish themselves. These are represented
by the spores of Leiotriletes, Acanthotriletes, Retusotriletes, Apiculatisporites and
© Springer Nature Switzerland AG 2020
M. Glikson-Simpson, Coal—A Window to Past Climate and Vegetation,
https://doi.org/10.1007/978-3-030-44472-3_3
101
The Microfloral Assemblages—Their
Environmental and Climatic
Interpretation
The questions arising from the systematic work of this study are: What do the pollen
and spores tell us? How significant are the sometime subtle changes in pollen/spore
assemblages? Is the composition of the spore/pollen assemblage indicative of environmental and atmospheric conditions? In order to answer these questions and reconstruct their environment, there is a need to organise the plant remains, namely the
pollen, spores and acritarchs into some grouping with common characteristics. These
are: appearing together in same stratigraphic level; sharing morphological features;
abundance in a lithological unit with specific petrology; prevalence of one type of
pollen, spore or acritarch.
On the basis of the above, the microfloral assemblages are grouped into four
biostratigraphic units (Figs. 3.2, 3.4, A.1):
Biostratigraphic Unit I is characterised by the following pollen: Parasaccites gondwanensis, Microbaculispora tentula and Punctatisporites gretensis. These
pollen comprise the oldest assemblage isolated and described from the Permian
sequence of the Collie samples, and may be referred to as the Parasaccites Zone.
This unit is present in all bore hole samples of Collie, Wilga Basins, Muja sub-basin
and Sue No. 1 bore. The lithology that this assemblage shares is tillites, which are
glacial deposits and contain the earliest Permian vegetation following the retreating
glaciers. This assemblage is poor in types of pollen on the generic level; the main
components of the microflora being the three pollen mentioned above. The ratios
between the three forms vary slightly from one sample to another. Nevertheless,
they comprise 80–90% of the total microflora of the Parasaccites zone. Parasaccites and Punctatisporites gretensis dominate this assemblage, although there are
bisaccate forms present, namely Potoniesporites neglectus and Illinites tectus. The
spores of the monolete Cycadopites cymbatus and the trilete Microbaculispora tentula accompany the assemblage. All these pollen except Illinites do not have any
significant presence beyond the Sakmarian. Illinites continues to be present in the
Artinskian Biostratigraphic Unit II.
Towards the end of the Sakmarian a change to less harsh climatic conditions
enabled a group of new plants to establish themselves. These are represented
by the spores of Leiotriletes, Acanthotriletes, Retusotriletes, Apiculatisporites and
© Springer Nature Switzerland AG 2020
M. Glikson-Simpson, Coal—A Window to Past Climate and Vegetation,
https://doi.org/10.1007/978-3-030-44472-3_3
101