OFR 151.pdf - CRC LEME

(Dacrycarpus, Dacrydium), Cupanieae, Droseraceae, Ericales, Ilex, Loranthaceae (Tricolpites
thomasii), Meliaceae (Dysoxylum), Nothofagus (Lophozonia, Nothofagus), Proteaceae
(including Triorites magnificus), Restionaceae (Milfordia homeopunctata), Santalum and
Sapotaceae.
Much more diverse microfloras are preserved in precisely dated marine clays, greensands and
marls at Browns Creek (Shafik and Idnurm 1997) but again few data are available.
Inferred Climate
The data confirm that climates were relatively cool (lower mesotherm range) and wet to very
wet (perhumid), but rainfall may have been weakly seasonal given the frequent occurrence of
Nothofagus (Fuscospora) and Araucariaceae.
3. Murray Basin
Microfloras of possible Middle Eocene and confirmed Late Eocene (Middle Nothofagidites
asperus Zone Equivalent) age are widely preserved at depth (Buccleugh and basal Olney
Formations) throughout the basin and adjacent areas in inland New South Wales. Detailed
reports or reviews of microfloras and pollen sequences, which illustrate changes in the
relative abundance of commonly occurring taxa during the Late Eocene, have been published
for the western (Truswell et al. 1985, McMinn 1986b), central (Macphail and Truswell 1989,
1993, Macphail 1999) and eastern (Harris and Morgan 1976, Martin 1987, 1993) sectors of
the basin.
With few exceptions the Late Eocene assemblages are very diverse and usually dominated by
Nothofagus (Brassospora) spp., with lesser amounts of Podocarpaceae (chiefly Lagarostrobos
and Podocarpus-Prumnopitys), Casuarinaceae and other (unspecified) angiosperms (see Fig. 8
in Martin 1993). Araucariaceae, Myrtaceae, Proteaceae and cryptogams are relatively rare.
Lagarostrobos and very diverse Proteaceae are more common in the south-east, Myrtaceae in
the north-east, and Araucariaceae in the west of the basin. Cyperaceae and Sparganiaceae are
consistently less frequent than in the Oligo-Miocene, including in the strongly marineinfluenced
south-west of the basin. Rare types include extinct taxa that appear to have
required warm conditions (Triorites magnificus) as well as taxa with mesotherm NLRs, e.g.
Anacolosa (Anacolosidites acutullus, A. luteoides, A. sectus), Apocynaceae (Alyxia), Palmae,
(Arecipites, Dicolpopollis), Caesalpinaceae, Malpighiaceae, Rubiaceae (Canthium), Santalum
and Sapotaceae.
Inferred Climate
Martin (1993) has proposed that systematic variation in the these groups of ecologically
related taxa reflect both climatic gradients and edaphic effects related to topography, with
Nothofagus occupying the drier sites and gymnosperms such as Lagarostrobos occupying
areas that were periodically inundated by freshwater. More generally, the data point to a
heterogeneous mosaic of floristically complex evergreen rainforest types growing under year
round high (perhumid) rainfall and cool to warm (mesotherm range) temperatures.
4. Gippsland Basin
Lower-Middle Nothofagidites asperus Zone sediments are routinely intersected in exploration
wells drilled in the offshore Gippsland (upper Latrobe Group) Basin. These range from
marginal marine facies to thick coal measures. Correlatives of the latter include the
Traralgon-2 Seam, Yallourn, in the onshore Gippsland Basin. In excess of 100 taxa have
been identified in the Gippsland Basin and many species have been described using
specimens from this basin (Cookson and Pike 1954, Stover and Partridge 1973). However,
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