OFR 151.pdf - CRC LEME

2. TIME SLICE T-2
Age Range: Early Eocene [54.8-49 Ma]
Zones: Malvacipollis diversus to Proteacidites asperopolus Zones
Upper Apectodinium hyperacanthum to Homotryblium tasmaniense
Zones
2.1 Macrofloras
Preservation of diverse macrofossil assemblages was probably better and more widespread
during the Eocene than for any other epoch in the Tertiary. To date, studies have tended to
focus on Tasmania, the onshore Gippsland Basin (Yallourn and Morwell Open Cuts), the
Dilwyn Formation (Wangerrip Group) and Anglesea deposits in Victoria, and Maslin Bay,
South Australia. The majority of these sites accumulated during the Middle-Late Eocene.
Others cannot be securely dated to a particular epoch within the Eocene. An important
exception is the late Early Eocene Regatta Point site, west coast of Tasmania.
Much emphasis has been placed on the description and evolutionary significance of the
macrofossils, in particular gymnosperms, where evolutionary trends in stomatal distributions
appear to reflect long-term palaeoclimatic trends (Hill and Carpenter 1991, Carpenter et al.
1994, Hill and Brodribb 1999). With the possible exception of cycads, the NLRs are
rainforest trees and shrubs. Most of these are extinct within the region, e.g. Araucaria in
Tasmania, or Australia as a whole, e.g. Acmopyle and Dacrycarpus (Podocarpaceae).
2.1.1 North-West Australia
Christophel (1994) cites Banksia (Proteaceae) as one of the taxa present in an Early Eocene
macroflora preserved at Merlinleigh in the Kennedy Ranges.
Inferred climate
Sclerophyll taxa such as Banksia may reflect strongly leached soils as much as seasonally dry
climates (Beard 1990, Hill 1998a, 1998b).
2.1.2 North-East Australia
A probable Early Eocene macroflora from Moranbah, Queensland, includes Araucariaceae
(Agathis), Casuarinaceae (Gymnostoma), Lauraceae and Proteaceae.
Inferred climate
Conditions appear to have been warm (mesotherm range) and seasonally wet (humidperhumid).
2.1.3 Central Australia
No known record.
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