OFR 151.pdf - CRC LEME

Araucariaceae (Araucaria) and Podocarpaceae (Dacrydium) with minor Gambierina,
Callitrichaceae and Casuarinaceae (McMinn 1989a). This gymnosperm-dominated
community appears to have been similar to coastal communities in the Gippsland Basin and
implies that Austral Conifer Forest formed the regional forest vegetation across southeastern
Australia during the Paleocene. Conditions appear to have been relatively cool (lower
mesotherm) and wet to very wet (humid-perhumid) but not to the extent of allowing extensive
Sphagnum raised bogs to develop across the uplands.
Inferred climate
The expansion of Araucariaceae and a diverse group of rainforest angiosperms during the
Late Paleocene is consistent with significant warming although mean temperatures are likely
to have remained within the lower mesotherm range. Rainfall appears to have remained high
(perhumid) with no pronounced seasonal bias.
2. South Coast of New South Wales
Sediments of probable Late Paleocene age have been dredged from the continental shelf off
Jervis Bay (Ocean Science Institute FR 5/91-30 DB13) on the South Coast of New South
Wales (M.K. Macphail and A.D. Partridge, unpubl. results).
The spore-pollen component is dominated by Casuarinaceae and podocarps, in particular
Dacrydium (Lygistepollenites balmei), Microcachrys, Podocarpus-Prumnopitys and
Podosporites. Blechnaceae and Lagarostrobos are frequent. Rare taxa include
Gleicheniaceae, Dacrydium (Lygistepollenites florinii), Halocarpus, Phyllocladus,
Callitrichaceae, probable Caryophyllaceae (Periporopollenites polyoratus), Gambierina,
ancestral Nothofagus, Proteaceae and several angiosperm types with no known NLRs. Taxa
with modern mesotherm affinities are absent, including Araucariaceae. Pollen dominance
almost certainly has been skewed by the Neves Effect. Nevertheless the results demonstrate
that a form of Austral Conifer Forest extend northwards along the eastern margin to about
palaeolatitude 57 0 S during the Paleocene. Dacrydium (Lygistepollenites balmei, L. florinii)
and Casuarinaceae appear to have lined coastal rivers or formed extensive swamp
communities on the coastal plains.
Inferred climate
Climates are interpreted to have been relatively wet (humid) and within the lower mesotherm
range. Low photoperiod is unlikely to have been ecologically significant at this latitude but
conditions may have been influenced by cool currents flowing northward along the eastern
margin.
3. Gambier Basin
Rowett (1997a) has recorded a possible Lygistepollenites balmei Zone Equivalent microflora
in McNicol-1 but few details are available.
4. Otway Basin
Late Paleocene microfloras from Copa-1, offshore western Otway Basin (Macphail and Hos
1990) are dominated by Araucariaceae (Araucariacites, Dilwynites) with frequent
Austrobuxus-type and Casuarinaceae. Gambierina is present in low numbers. Otherwise the
only detailed data on Paleocene floras come from outcrops of the Pebble Point and Dilwyn
Clay Formations (Wangerrip Group) near Princetown on the Otway coast (see Table 1 in
Harris 1965a, Partridge 1999). Foraminifera and dinoflagellates provide independent age
control.
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