- Title
- Fire and Late Oligocene to Mid-Miocene peat mega-swamps of south-eastern Australia : A floristic and palaeoclimatic interpretation
- Creator
- Sluiter, Ian; Blackburn, David; Holdgate, Guy
- Date
- 2016
- Type
- Text; Journal article; Conference paper
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/154312
- Identifier
- vital:11100
- Identifier
-
https://doi.org/10.1071/BT16165
- Identifier
- ISBN:0067-1924
- Abstract
- This article is a presentation that formed part of the Ecological Society of Australia's annual symposium entitled "Fire in Australia : how was the biota prepared for human occupation". The Late Oligocene to Mid-Miocene (25-13million years ago) brown coals of the Gippsland Basin in southern Victoria, Australia, were deposited in peat mega-swamps, unlike any in the world at the present day. The swamps preserve a rich botanical suite of macro- and microfossils, many of which can be identified with plant genera and families present today in Australia, New Caledonia, New Zealand and New Guinea. The peat-forming environments also preserve evidence of past burning in the form of micro-charcoal as well as macro-charcoal, the latter being evident as regional lenses or layers of fusinite, generally in coals of the darkest colour termed dark lithotypes. The presence of micro-charcoal in dark and some other lighter lithotypes indicated that fires also burnt locally, although they may have been extinguished before regional-scale burning occurred. It is also feasible that some peat mega-swamp plant communities dominated by rainforest angiosperm plants may have been fire excluders and prevented widespread fires from developing. Pollen and macrofossil evidence is presented of a distinctive southern conifer and angiosperm flora with an open canopy, primarily associated with the darkest coals that formed in the wettest parts of the peat-forming environment. Elsewhere, swamp forests with a large rainforest component grew on swamps raised appreciably above the regional groundwater table in a structural context akin to the ombrogenous peats of tropical coastal Sumatra and Sarawak. These vegetation types were not fire prone, but may have occasionally burnt at a local scale or at forest margins. Evidence is presented for the existence of seasonal climatic conditions that would appear to have facilitated a drying-out of the peat swamps in the warmest months of the year. A mesothermal climate was invoked where mean annual precipitation was at least 1500mm, and possibly as much as 2000mm, and mean annual temperatures were ∼19°C. © 2013 CSIRO.
- Publisher
- CSIRO
- Relation
- Australian Journal of Botany Vol. 64, no. 8 (2016), p. 609-625
- Rights
- Copyright © 2013 CSIRO.
- Rights
- This metadata is freely available under a CCO license
- Subject
- Brown coal; Floras; Gippsland Basin; Palaeoclimates; Coniferophyta; Magnoliophyta
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