OFR 151.pdf - CRC LEME

2. TIME SLICE K-2
Age Range: Aptian – Albian [115- 97.5 Ma]
Zones: Cyclosporites hughesii to Phimopollenites pannosus Zones
Odontochitina operculata to lower Xenascus asperatus Zones
2.1 Macrofloras
Basins that preserve macrofossil records for the Berriasian-Barremian usually preserve
Aptian-Albian macrofloras as well. However the only comprehensive records come from
basins located along the present-day southern margin, then at high palaeolatitude (70-80 0 S)
along the palaeo-western margin (see Figure 5).
2.1.1 North-West Australia
No known record.
2.1.2 North-East Australia
1. Marlborough Basin
A sparse macroflora preserved in the Marlborough Basin, southern Queensland, indicates that
forests or woodlands on the northernmost of the four islands making up Australia during the
Aptian included Araucariaceae, Ginkgoites, pteridosperms/Pentoxylales (Taeniopteris),
sphenopsids and ferns. Dettmann and Clifford (2000a) have recorded propagules resembling
gemmae produced by modern liverworts (Marchantiales) in latest Albian sediments from the
south-east of the Eromanga Basin.
Inferred climate
Since the Marlborough Basin was located at a palaeolatitude of about 75 0 S, it is reasonable to
assume that conditions were humid and temperatures were below freezing (lower microtherm)
during winter.
2.1.3 Central Australia
1. Eromanga and Surat Basins
Palaeogeographic reconstructions indicate the depocentre of the Eromanga Basin was located
at about 60 0 S. The Euromanga and Surat Basins to the east were part of an extensive
epicontinental seaway stretching from the palaeo-northern margin at about ~50 0 S southwards
to about palaeolatitude 80 0 S. Silicified wood with narrow growth rings is preserved in
carbonate concretions in the Early Albian, upper Bulldog Shale and Toolebuc Formation and
a cycad is preserved in the Middle-Late Albian Allaru Mudstone in the Eromanga Basin but
other macrofossils from this and the Surat Basin await identification (references in Dettmann
et al. 1992).
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