eCite Digital Repository

Coastal erosion reveals a potentially unqiue Oligocene and possible periglacial sequence at present-day sea level in Port Davey, remote South-West Tasmania

Citation

Macphail, M and Sharples, C and Bowman, D and Wood, S and Haberle, S, Coastal erosion reveals a potentially unqiue Oligocene and possible periglacial sequence at present-day sea level in Port Davey, remote South-West Tasmania, Papers and Proceedings of the Royal Society of Tasmania, 148 pp. 43-59. ISSN 0080-4703 (2014) [Refereed Article]


Preview
PDF
Restricted - Request a copy
820Kb
  

Copyright Statement

Copyright 2014 Royal Society of Tasmania

Official URL: http://rst.org.au/publications/papers-and-proceedi...

Abstract

Cut-back of a sea-cliff at Hannant Inlet in remote South-West Tasmania has exposed Oligocene clays buried under Late Pleistocene "colluvium" from which abundant wood fragments protrude. The two units are separated by a transitional interval defined by mixed Oligocene and Pleistocene microfloras. Microfloras preserved in situ in the clay provide a link between floras in Tasmania and other Southern Hemisphere landmasses following onset of major glaciation in East Antarctica during the Eocene-Oligocene transition (c. 34 Ma). The Late Pleistocene "colluvium" preserves abundant fossil pollen of the shrub conifer genus Pherosphaera (al. Microstrobos). Assuming the parent plants had the same upper subalpine-alpine ecology as living Pherosphaera hookeriana, the microflora provides evidence for cold, wet conditions in the Port Davey lowlands during a low sea-level stand. The same data highlight the failure of Pherosphaera to regain its Pleistocene distribution during the Postglacial period. Our data are inconclusive whether Late Pleistocene conditions in Hannant Inlet were periglacial, i.e., the Oligocene sediments were turbated by freeze-thaw processes, or have been reworked by fluvial processes into the Pleistocene "colluvium". Nevertheless, the inferred cold-climate is consistent with the former hypothesis. The sequence is sealed under cross-bedded coarse quartzite gravels of presumed Last Glacial Stage age.

Item Details

Item Type:Refereed Article
Keywords:coastal erosion, stratigraphy, Cenozoic palynostratigraphy, Tasmania, Antarctica, South America, Oligocene, Pleistocene, Lophosoria, Embothrium, Pherosphaera, trans-oceanic migration
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Physical Geography and Environmental Geoscience not elsewhere classified
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Coastal and Estuarine Environments
Author:Sharples, C (Mr Chris Sharples)
Author:Bowman, D (Professor David Bowman)
Author:Wood, S (Mr Samuel Wood)
ID Code:97479
Year Published:2014
Deposited By:Geography and Environmental Studies
Deposited On:2014-12-18
Last Modified:2015-04-23
Downloads:0

Repository Staff Only: item control page