OFR 151.pdf - CRC LEME

4.2.7 Tasmania
1. Bass Basin
Turonian-Santonian microfloras are preserved in the Durroon Sub-basin, then lying at a
palaeolatitude of about 77 0 S off the north-east coast (Partridge 1999, M.K. Macphail and A.D.
Partridge unpubl. data). These are dominated by araucarians (chiefly Agathis/Wollemia)
podocarps (Podocarpus-Prumnopitys) and Cupressaceae (Cupressacites). Values of the last
taxon increase up-section (possible due to the Neves Effect) as do the relative abundance of
angiosperms and a distinctive freshwater alga, Rimosicysta. Nevertheless, the cryptogam and
angiosperm flora appear to be less diverse that in correlative microfloras from the Gippsland
and Otway Basins.
Inferred climate
The combined data point to seasonally cool-cold (microtherm range) and wet (humidperhumid)
conditions in northern Tasmania although it is difficult to determine whether
floristic impoverishment reflects freezing temperatures or prolonged darkness during winter.
4.3 Other records
4.3.1 South-East Australia
A Turonian ammonite from the Otway Basin yielded a palaeotemperature of 28 0 C
(megatherm range) although the associated foraminifera appear to represent a cold-water
fauna (references in Dettmann 1973).
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