OFR 151.pdf - CRC LEME

3. Capricorn Basin
Relative abundance data from the Aquarius-1 well imply Podocarpaceae-dominated forests
were replaced by Casuarinaceae (Gymnostoma) dominated communities during the possible
Late Eocene. Associated taxa include Araucariaceae, Nothofagus, Myrtaceae, Cupanieae and
Poaceae (cf. Hekel 1972, Foster 1982). Rare taxa include Loranthaceae, Poaceae, Nypa and
Rhizophoraceae. Correlative microfloras from the Capricorn-1A well include Podocarpaceae
(Dacrydium), Anacolosa, Palmae (Arecipites), Cupanieae, Loranthaceae (Tricolpites
thomasii), Malvaceae (Malvacearumpollis), Nothofagus (Brassospora, Fuscospora) spp.,
Nypa and the earliest record of Onagraceae (cf. Epilobium) in Australia. Except for
Nothofagus, which is likely to represent temperate rainforest on the upper slopes and summit
of the Eastern Highlands, the microfloras preferentially represent plants growing along the
major coastal rivers.
Inferred Climate
The presence of extensive brackish water lakes and subtropical-tropical mangroves, including
Nypa in the Capricorn Basin, implies conditions were very warm (upper mesothermmegatherm)
and seasonally very wet (perhumid). Rainfall at higher elevations almost
certainly was more uniform due to orographic effects and temperatures were cooler (lower
mesotherm) for the same reason.
4. Northern Tablelands
Organic deposits are preserved under basalt flows on Mt. Tamborine on the New South
Wales/Queensland Border (Cookson and Pike 1954, Harris 1965d), and on the Northern
Tablelands of New South Wales (McMinn 1989b, 1989c, 1989e, Pickett et al. 1990).
Pollen dominance is highly variable, consistent with the microfloras being sourced from plant
communities growing close to the sites. For example, sporadically common taxa in Lower
Nothofagidites asperus Zone Equivalent microfloras from Glen Innes (New England district)
include ferns (Blechnaceae, Calochlaena/Culcita, Cyathea, Polypodiaceae), Podocarpaceae
(Podocarpus-Prumnopitys), Nothofagus (Brassospora) spp., Casuarinaceae, Ericales, and
unidentified tricolporate types. Other gymnosperms, including Araucariaceae, Dacrydium
and Lagarostrobos, are relatively uncommon; rare angiosperms include Cupanieae,
Euphorbiaceae (Austrobuxus-type), Ilex, Santalum and Tiliaceae. The regional vegetation is
likely to have been temperate rainforest with fern communities occupying disturbed sites.
Inferred Climate
Mean annual temperatures are suggested to have been relatively cool (lower mesotherm).
Effective precipitation appears to have high to very high (perhumid) due to orographic effects.
5. North-west plains of New South Wales
Late Eocene microfloras are preserved at Tilpa (DWR Bore 30685) in a palaeovalley of the
Darling River near Bourke (Martin 1997b), and other palaeodrainage systems e.g. Darling
Bore DWR 36839 and BMR Wilcannia DDH 86839 (M.K. Macphail unpubl. results). Rare
occurrences of Anacolosidites sectus, Cranwellia striata, Proteacidites reticulatus and
Tricolpites thomasii indicate the age range of the deposits is Middle-Late Eocene.
Pollen dominance is shared between Nothofagus (Brassospora) species (15-51%),
Casuarinaceae (8-40%) and Trimeniaceae (3-13%). Frequent to common (1-10%) taxa
include Podocarpaceae (Dacrydium, Podocarpus-Prumnopitys and occasionally
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