OFR 151.pdf - CRC LEME

Dominants include fresh to brackish water algae and Nothofagus (Brassospora) spp. including
frequent Nothofagidites falcatus (up to 42%), Casuarinaceae (up to 20%) and Myrtaceae (up
to 18%). Less common to rare taxa include Blechnaceae, Calochlaena/Culcita,
Gleicheniaceae, Lygodium, Pteris, Araucaria, Agathis/Wollemia, Cupressaceae, Dacrycarpus,
Dacrydium, Ephedra, Anacolosa (Anacolosidites cf. sectus), Archidendron-type, Palmae
(Arecipites), Beauprea, Caesalpinaceae, Caryophyllaceae (Polyporina sp.), Cissus,
Convolvulaceae, Coprosma-type (Palaeocoprosmadites), Cupanieae, Euphorbiaceae
(Austrobuxus-type), Ilex, Loranthaceae (Gothanipollis), Myrtaceae (including Austromyrtustype
but not Eucalyptus), Nothofagus (Fuscospora, Lophozonia), Malvaceae, Musgraveinae,
Polygalaceae, Sapotaceae, Villarsia-type and a diverse array of described and undescribed
Proteaceae. Many of the former had warm temperate to tropical NLRs and many Proteaceae
types are recorded in the possible Late Eocene Yaamba Basin. Given the location of the two
sites, the source vegetation almost certainly represent an altitudinal sequence of subtropical to
cool temperate rainforest types growing on the western slopes of the Eastern Highlands
(Leichhardt Ranges-Redcliffe Tableland).
Inferred climate
Conditions are likely to have been wet to very wet (perhumid) with temperatures decreasing
from warm (upper mesotherm) in the lowlands to cool (lower mesotherm) on the summit of
adjacent ranges. The paucity of Araucariaceae is against rainfall being strongly seasonal.
2. South-east Queensland
a. Casuarina Basin
A latest Eocene-Oligocene swamp microflora is preserved in the Casuarina Basin near
Rockhampton (Dettmann and Clifford 2000b). Riparian and dryland taxa include Lygodium,
Cyatheaceae, Anacardiaceae (Ailanthipites), Palmae (Arecipites), Casuarinaceae,
Convolvulaceae (Perfotricolpites digitatus), Cupanieae, Ilex, Liliaceae, Malvaceae, noneucalyptoid
Myrtaceae, Proteaceae (including Proteacidites pachypolus) and Sapotaceae.
Rare gymnosperms include Agathis/Wollemia, Dacrydium and Podocarpus-Prumnopitys.
Aquatic taxa include fresh- to brackishwater algae (Botryococcus, Pediastrum), Restionaceae,
Sparganiaceae and Typhaceae.
b. Capricorn Basin
Microfossil evidence of the Oligocene-Middle Miocene flora and vegetation in northeastern
Australia primarily comes from two offshore wells, Aquarius-1 and Capricorn-1A (Hekel
1972). Independent age control consists of 30 year old foraminiferal dates for Aquarius-1
(Palmieri 1971). However, the broad age determinations proposed for this well and Aquarius-
1 are consistent with time distribution data from the Murray-Darling Basin (cf. Macphail
1999). If correctly dated, the combined data imply Nothofagus-dominated communities first
became prominent in southern Queensland during the possible Late Oligocene and remained
common throughout the Early Miocene (Foram Zones N4-N7).
Values of non-eucalypt Myrtaceae (characteristic of wet sclerophyll forest and some forms of
subtropical rainforest) increase in relative abundance over the same period. Since presumed
correlative assemblages from the Duaringa and Hillborough Basins on the central Queensland
coast (and Mt. Coolon in central Queensland) also are Nothofagus-dominated but include a
diverse Myrtaceae component, the trend appears to have been a regional one in eastern
Queensland. Nypa is last recorded during the Early Miocene (N5-N7) in Aquarius-1 but is
absent in correlative sections in Capricorn-1A.
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