Thursday, 30 August 2007 - 10:10 AM
4.A.D-1
The Neogene biota of the Transantarctic Mountains
Allan C. Ashworth1, Adam R. Lewis1, David R. Marchant2, Rosemary A. Askin3, David J. Cantrill4, Jane E. Francis5, Melanie J. Leng6, Angela E. Newton7, J. Ian Raine8, Mark Williams9, and Alex P. Wolfe10. (1) Department of Geosciences, North Dakota State University, Fargo, ND 58105-5517, (2) Department of Earth Sciences, Boston University, Boston, MA 02215, (3) 1930 Bunkhouse Drive, Jackson, WY 83001, (4) Plant Sciences and Biodiversity, Royal Botanic Gardens Melbourne, Victoria, 3141, Australia, (5) School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom, (6) NERC Isotope Geosciences Laboratory, Keyworth, NG12 5GG, United Kingdom, (7) Department of Botany, Natural History Museum, London, SW7 5BD, United Kingdom, (8) GNS Science, Lower Hutt, 5040, New Zealand, (9) Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom, (10) Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB TSG 2E3, Canada
Neogene fossil assemblages are described from the Transantarctic mountains. The plant fossils, include diatoms and algal spores, megaspores of Isoetes, pollen of angiosperms and gymnosperms, wood and leaves of Nothofagus, cushion growth forms of a vascular plant and a moss species, mats of exceptionally well-preserved moss species with delicate leaves attached to stems, and achenes and fruits of vascular plant species including Ranunculus. The invertebrate fossils include disarticulated chitinous parts of beetles and flies, cypridoidean ostracods and the shells of freshwater molluscs. The only vertebrate fossil is that of a fish. The fossil assemblages require considerably warmer temperatures than are available within the Transantarctic Mountains today; estimated to be at least two to three summer months annually with mean temperatures of 4-5°C. Early interpretations allowed for the extinction of this terrestrial biota to have occurred as late as the Pliocene but a Miocene age now seems more probable.