OFR 151.pdf - CRC LEME

Inferred climate
The Regatta Point data are compelling evidence that very warm (upper mesotherm) conditions
persisted within Macquarie Harbour into late Early Eocene time. Explanations include warm
oceanic currents flowing southward down the West Coast of Tasmania or (preferred) that
water temperatures within Macquarie Harbour remained atypically warm. Conditions on the
East Coast of Tasmania appear to have been cooler (lower mesotherm) during the Early
Eocene. Climates overall appear to have been wet to very wet (perhumid) but the paucity of
cryptogams and variable representation of Nothofagus between Buckland and Deloraine may
indicate that summers were relatively dry (weakly seasonal) in the south-east.
2.3 Other Records
2.3.1 North-East Australia
1. North-east Queensland
Feary et al. (1991) have estimated SSTs off the north-east coast of Queensland during the
early Early Eocene were up to 16.0-18.0 0 C (lower mesotherm range).
2. South-east Queensland
Skeletal remains of arboreal fructivores, frogs, snakes, a possible freshwater crocodile and
turtles (Tingamarra Local Fauna) are preserved below an early Early Eocene (54 Ma) basalt
near Murgon in southeastern Queensland (Godthelp et al. 1992). Archer et al. (1994) suggest
the climate was mild to warm (mesotherm range) throughout the year.
2.3.2 South-West Australia
1. Carnarvon Basin
Foram and lithostratigraphic evidence indicate a cooling in oceanic temperatures and
increased continental run-off during the Early Eocene. The latter implies increasing wet
(possibly humid) conditions in the northern Carnarvon Basin (Apthorpe 1988).
2.3.3 South-East Australia
1. Otway and Gippsland Basins
Episodic excursions of dinoflagellates belonging to the warmer water Wetzelielliodeae group
indicate sea surface temperatures were generally warmer during the Early Eocene than during
the Paleocene or Middle Eocene (Partridge 1976, A.D. Partridge pers. comm.).
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