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Original Article |
1 1School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK (e-mail: j.francis@earth.leeds.ac.uk)
2 2Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
3 3Department of Geosciences, North Dakota State University, Fargo, ND 58105517, USA
4 4School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
5 5Present address: School of Earth & Environment, University of Leeds, Leeds LS2 9JT, UK
The Neogene Meyer Desert Formation, Sirius Group, at Oliver Bluffs in the Transantarctic Mountains, contains a sequence of glacial deposits formed under a wet-based glacial regime. Within this sequence fluvial deposits have yielded fossil plants that, along with evidence from fossil insects, invertebrates and palaeosols, indicate the existence of tundra conditions at 85°S during the Neogene. Mean annual temperatures of c. –12 °C are estimated, with short summer seasons with temperatures up to +5 °C. The current published date for this formation is Pliocene, although this is hotly debated. Reconstructions produced by the TRIFFID and BIOME 4 vegetation models, utilizing a Pliocene climatology derived from the HadAM3 General Circulation Model (running with prescribed boundary conditions from the US Geological Survey PRISM2 dataset), also predict tundra-type vegetation in Antarctica. The consistency of the model outputs with geological evidence demonstrates that a Pliocene age for the Meyer Desert Formation is consistent with proxy environmental reconstructions and numerical model reconstructions for the mid-Pliocene. If so, the East Antarctic Ice Sheet has behaved in a dynamic manner in the recent geological past.
