OFR 151.pdf - CRC LEME

Inferred climate
The stems are believed to represent podocarp-dominated forests or woodlands (Austral
Conifer Forest) growing under wet (humid) but strongly seasonal and cool-cold (microtherm
range) conditions on uplands surrounding the Eromanga Basin (Francis and Frakes 1993).
2.1.4 South-West Australia
1. Carnarvon and Perth Basins
Fossil macrofloras consisting of permineralised wood are preserved in the Early Aptian
Muderong Shale and Middle Aptian-Albian Windalia Radiolarite in the Carnarvon Basin, and
Early Aptian Dandaragan Sandstone in the Perth Basin (McLoughlin 1996).
Inferred climate
McLoughlin (ibid) suggests that araucarians and podocarps are likely to have dominated tree
communities, implying conditions were humid. Based on the middle palaeolatitude location
(~55 0 S) on the palaeo-northern margin, mean annual temperatures may have been relatively
warm (lower mesotherm) and seasonal contrasts less marked than in inland regions.
2.1.5 Central southern Australia
No known record.
2.1.6 South-East Australia
Aptian to Early Albian (Zone C) and Early to Late Albian (Zone D) macrofloras are widely
preserved across the Otway and Gippsland Basins, which were located on the palaeo-western
margin between latitudes 70-80 0 S (Douglas 1969, 1973a, 1986, 1994). The most important of
these floras is a Zone C macroflora preserved in the Koonwarra Beds, onshore Gippsland
Basin. The Zone C/D boundary approximates to the Aptian/Albian boundary.
1. Aptian to Early Albian
The Koonwarra Beds preserve a particularly diverse record of the earliest Aptian plants and
animals living in and around a large (>2 km diameter) freshwater lake (Drinnan and
Chambers 1986, Rich et al. 1988).
The flora includes most of the major plant taxa forming Austral Conifer Forest elsewhere in
southern Australia during the early Cretaceous. These plants ranged in size from bryophytes
to probably tall gymnosperms. Angiospermids are represented by a flower (Taylor and
Hickey 1990) and fossil pollen. Important taxa include Araucariaceae, Podocarpaceae,
Ginkgoites, pteridosperms/Pentoxylales (Taeniopteris), ferns and fern allies (Adiantites,
Gleichenites), sphenopsids (Equisetum, Phyllotheca, Sphenopteris), isoetaleans (including
Isoetes), lycopods (Lycopodium), mosses (including Sphagnales) and liverworts
(Jungermanniales, Anthocerotae).
The woody flora included both deciduous and evergreen taxa. Many of the sphenopsids, ferns
and fern allies closely resemble their nearest living relatives, e.g. Equisetum, Gleichenia and
Lycopodium. The bryophyte flora included ground and epiphytic species. The remains of
small ‘polar’ dinosaurs and birds are preserved in the Koonwarra Beds and correlative
deposits elsewhere in southern Victoria.
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