OFR 151.pdf - CRC LEME

also include relatively frequent Nothofagus (Fuscospora) spp. and tricolpate angiosperms.
Rare taxa include Sphagnum, probable shrub podocarps (Microcachrys, Podosporites),
Gambierina, Ilex, and a probable Caryophyllaceae (Periporopollenites polyoratus). Charcoal
is common in the Mt. Royal assemblage, and this microflora and those from Tamworth also
preserve halophytic dinoflagellate cysts (Ceratopsis spp.) similar to those found in the Lake
Eyre Basin (see below).
Inferred climate
During the Late Tertiary, Araucariaceae are typically associated with weakly seasonal, warm
and wet climates (Macphail and Truswell 1989). Paleocene araucarians may have had similar
preferences, based on the higher relative abundance of Araucaria in Late Paleocene
microfloras on the Northeastern Tablelands than in correlative assemblages on the
Southeastern Highlands (see below). If correct, seasonally warm (mesotherm range) and wet
(humid-perhumid) climates were in existence in northeastern New South Wales sometime
during the Late Paleocene despite isotope data indicating cooler (microtherm) SSTs in
northeastern Queensland.
1.2.3 Central Australia
1. Lake Eyre Basin
Probable Late Paleocene (Upper Lygistepollenites balmei Zone Equivalent) microfloras are
preserved at the base of the Eyre Formation in the Clayton-3 well (Alley 1986) and BMR
Muloorina-2 and Poonarunna-1 wells in the Lake Eyre Basin (Sluiter 1991, Martin 1998b).
The latter wells preserve the earliest recorded evidence of extensive burr-reed
(Sparganiaceae) swamps in inland Australia (Alley 1998).
The Clayton-3 microfloras are co-dominated by ferns (Blechnaceae, Cyathea, Cyathidites,
Gleicheniaceae), Podocarpaceae (Dacrydium, Lagarostrobos, Microcachrys, Podocarpus-
Prumnopitys) and Callitrichaceae. Rare taxa include the extinct Dacrydium clade
(Lygistepollenites balmei) as well as taxa that are more typical of Early Eocene microfloras,
e.g. Cupanieae, Pandanaceae (Freycinetia), Sapotaceae and extinct species such as Tricolpites
incisus (possibly Loranthaceae) and Tricolporites leuros (possibly Meliaceae). Rare taxa in
Lake Eyre Bore 8A include a probable early species of Eucalyptus (Myrtaceidites tenuis) and
Proteacidites pachypolus (Alley 1983a).
The Muloorina-2 and Poonarunna-1 sequences are equally difficult to date due to the cooccurrence
in the same assemblage of species that are used to subdivide Late Paleocene and
Early Eocene time in the Gippsland Basin. Relative abundance data compounds this problem
since the closest analogues of the Paleocene assemblages in Poonarunna-1 occur in an interval
(17-34 m) in Muloorina-2, which may be Early Eocene in age (M.K. Macphail, unpubl.
observ.). Other unusual features of the two palynosequences are:
a. The only common gymnosperm(s) in Muloorina-2 are families (Cupressaceae and/or
Taxodiaceae) that now are most common on the sub-humid-humid Southeastern Highlands
and adjacent central west slopes of New South Wales and in the alpine zone in Tasmania.
Podocarps are rare (Dacrydium, Lagarostrobos) to frequent (Microcachrys, Podocarpus)
whilst Araucariaceae occur in isolated samples only. Correlative microfloras in Poonarunna-
1, located 280 km to the south of Muloorina-2, are dominated by podocarps, chiefly
Podocarpus but include frequent to common (up to 10%) Dacrydium, Lagarostrobos and
Microcachrys. Conversely, Cupressaceae-Taxodiaceae pollen occur in trace numbers only.
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