OFR 151.pdf - CRC LEME

Palaeo-central Australia (~60-70 0 S)
Regional climates were strongly influenced by marine transgression and regression events.
Effective precipitation was sufficiently high (humid-perhumid) to support Sphagnum bogs in
the southern Eromanga Basin, although this may have been as much due to low (microtherm
range) temperatures reducing evapo-transpiration losses as to uniformly wet (humidperhumid)
climates. Mineralogical and sedimentary evidence confirm that water and
therefore air temperatures fell below freezing during winter months, allowing ice to
accumulate on uplands surrounding the Eromanga Basin. In spite of the strong seasonal
contrasts in temperature and photoperiod, summers were sufficiently warm (upper
microtherm) to support woody plant growth.
Palaeo-southern Australia (~70-80 0 S)
Palaeobotanical evidence for Aptian-Albian climates in palaeo-southern Australia (present
day south-east to north-east Australia) is distorted by the location of many sites in the then
north-west to south-east orientated Australo-Antarctic Rift System. Other complicating
factors include repeated tectonic disturbance and the ameliorating effect of marine flooding of
the rift system as far ‘east’ as the Otway Basin. There is weak evidence that wet to very wet
(humid-perhumid) conditions extended along the palaeo-southern margin, from the Otway
Basin to the Maryborough Basin in southern Queensland. Temperatures were strongly
seasonal (microtherm range) and probably below freezing during winter months.
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