Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/cp-2018-52
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
25 May 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Climate of the Past (CP).
Pleistocene glacial history of the New Zealand subantarctic islands
Eleanor Rainsley1, Chris S. M. Turney2,3, Nicholas R. Golledge4,5, Janet M. Wilmshurst6,7, Matt S. McGlone6, Alan G. Hogg8,9, Bo Li10,11, Zoë A. Thomas2,3, Richard Roberts10,11, Richard T. Jones12,†, Jonathan G. Palmer2,3, Verity Flett13, Gregory de Wet14, David K. Hutchinson15, Mathew J. Lipson2, Pavla Fenwick16, Ben R. Hines17, Umberto Binetti18, and Christopher J. Fogwill1,2 1ICELAB, School of Geography, Geology and the Environment, University of Keele, Staffordshire, ST5 5BG
2Climate Change Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
3Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, University of New South Wales, NSW 2052, Australia
4Antarctic Research Centre, Victoria University of Wellington, Wellington 6140, New Zealand
5GNS Science, Avalon, Lower Hutt 5011, New Zealand
6Long Term Ecology Laboratory, Landcare Research, Lincoln, New Zealand
7School of Environment, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
8Waikato Radiocarbon Laboratory, University of Waikato, Private Bag 3105, Hamilton, New Zealand
9Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, University of Waikato, Hamilton 3240, New Zealand
10Centre for Archaeological Science, School of Earth and Environmental Sciences, University of Wollongong, Australia
11Australian Research Council (ARC) Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, NSW 2522, Australia
12Department of Geography, University of Exeter, Exeter EX4 4RJ, UK
13School of the Environment, University of Dundee, Nethergate DD1 4HN, UK
14Institute of Arctic and Alpine Research, University of Colorado, Boulder, Boulder, CO, USA
15Bolin Centre for Climate Research and Department of Geological Sciences, Stockholm University, Stockholm, Sweden
16Gondwana Tree-Ring Laboratory, PO Box 14, Little River, Canterbury 7546, New Zealand
17School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand
18Centre for Ocean and Atmospheric Studies, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
deceased
Abstract. The New Zealand subantarctic islands of Auckland and Campbell, situated between the Subtropical Front and the Antarctic Convergence in the Pacific sector of the Southern Ocean, provide valuable terrestrial records from a globally-important climatic region. Whilst the islands show clear evidence of past glaciation, the timing and mechanisms behind Pleistocene environmental and climate changes remain uncertain. Here we present a multidisciplinary study of the islands – including marine and terrestrial geomorphological surveys, extensive analyses of sedimentary sequences, a comprehensive dating program, and glacier flowline modelling – to investigate multiple phases of glaciation across the islands. We find evidence that the Auckland Islands hosted a small ice cap at 384,000 ± 26,000 years ago (384 ± 26 ka), most likely during Marine Isotope Stage 10, a period when the Subtropical Front was pushed northwards by seven degrees, and consistent with hemispheric-wide glacial expansion. Despite previous interpretations that suggest the maximum glacial extent occurred in the form of valley glaciation at the Last Glacial Maximum (LGM; ~ 21 ka) age, our combined approach suggests minimal LGM glaciation across the New Zealand Subantarctic Islands, and that no glaciers were present during the Antarctic Cold Reversal (ACR; ~ 15–13 ka). Instead, our flowline modelling, constrained by field evidence, implies that despite a regional mean annual air temperature depression of ~ 5 °C during the LGM, a combination of high seasonality and low precipitation left the islands incapable of sustaining significant glaciation. We suggest that northwards expansion of winter sea ice during the LGM and subsequent ACR led to precipitation starvation across the mid to high latitudes of the Southern Ocean, resulting in restricted glaciation of the subantarctic islands.
Citation: Rainsley, E., Turney, C. S. M., Golledge, N. R., Wilmshurst, J. M., McGlone, M. S., Hogg, A. G., Li, B., Thomas, Z. A., Roberts, R., Jones, R. T., Palmer, J. G., Flett, V., de Wet, G., Hutchinson, D. K., Lipson, M. J., Fenwick, P., Hines, B. R., Binetti, U., and Fogwill, C. J.: Pleistocene glacial history of the New Zealand subantarctic islands, Clim. Past Discuss., https://doi.org/10.5194/cp-2018-52, in review, 2018.
Eleanor Rainsley et al.
Eleanor Rainsley et al.
Eleanor Rainsley et al.

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