Lead isotopic evidence for an Australian source of aeolian dust to Antarctica at times over the last 170,000 years |
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| Authors: | Patrick De Deckker Marc Norman Ian D. Goodwin Alan Wain Franz X. Gingele |
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| Affiliation: | 1. Research School of Earth Sciences, The Australian National University, Canberra ACT 0200, Australia;2. Climate Risk CoRE, Department of Environment and Geography, Macquarie University NSW 2109, Australia;3. CAWCR — High Impact Weather Team, Bureau of Meteorology, PO Box 1636, Melbourne VIC 3001, Australia;4. Formerly of Department of Earth and Marine Sciences, The Australian National University, Canberra ACT 0200, Australia;1. Department of Archaeology and Natural History, Australian National University, Canberra, ACT, Australia;2. Department of Biology, University of Bergen, Bergen, Norway;3. Southern Cross Geoscience, Southern Cross University, Lismore, NSW, Australia;1. Instituto de Ecología y Biodiversidad, Departamento de Ciencias Ecológicas, Universidad de Chile, Santiago, Chile;2. Pyrenean Institute of Ecology, Spanish Scientific Research Council, Zaragoza, Spain;3. School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand;4. Lamont-Doherty Earth Observatory, Columbia University, New York, United States;1. National Centre for Antarctic and Ocean Research, Vasco-da-Gama, Goa, India;2. Department of Community Medicine, Sikkim Manipal Institute of Medical Sciences, Gangtok, India;1. Monash Indigenous Studies Centre, Monash University, Clayton, Victoria, 3800, Australia;2. Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Canberra, Australia;3. Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, EDYTEM, F-73376, Le Bourget du Lac Cedex, France;4. School of Social Science, The University of Queensland, St Lucia, Queensland, 4072, Australia;5. Radiocarbon Dating Laboratory, University of Waikato, Hamilton, 3240, New Zealand;6. Centre National de Préhistoire, Ministère de la Culture et de la Communication, UMR PACEA, Université de Bordeaux 1, 24000, Périgueux, France;7. Centre for Tropical Environmental and Sustainability Science, School of Earth and Environmental Sciences, James Cook University, PO Box 6811, Cairns, Queensland, 4870, Australia;8. School of Humanities and Communication, Public Memory Centre, University of Southern Queensland, Toowoomba, Queensland, 4350, Australia;1. Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia;2. Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia;3. School of Earth, Atmosphere and Environment, Monash University, Clayton, VIC 3800, Australia;4. ANU Medical School, The Australian National University, Canberra, ACT 0200, Australia;5. NIOZ-Royal Netherlands Institute for Sea Research, P.O. Box 59, Den Burg 1790 AB, The Netherlands;6. MARUM, Center for Marine Environmental Sciences, P.O. Box 330440, Bremen 28334, Germany;7. Cluster Earth & Climate, Department of Earth Sciences, Faculty of Earth and Life Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands |
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| Abstract: | Systematic analysis of Pb, Sr and Nd isotopes of 32 fluvial clay samples (< 2 µm fraction) from many of the major tributaries of the vast (1.106 km2) Murray Darling Basin (MDB), located in semiarid southeastern Australia, displays similar isotopic values between some MDB clays and dust from several ice core samples from the EPICA Dome C in Antarctica. Close scrutiny of several ratios of the four Pb isotopes, and in particular 208Pb/207Pb versus 206Pb/207Pb, shows that several samples from the Darling-sub-basin of the MDB display similar values for the same isotopes for Dome C samples from different ages, and more particularly during wet phases in Australia [Marine Isotopic Stages 5e, 3 and 1]. The combination of Nd and Sr isotopic ratios from the same MDB fluvial clays clearly eliminates the Murray sub-basin, and supports the Darling sub-basin as a potential source of aeolian material to Antarctica. Overall, the Australian dust supply to Antarctica predominantly occurred during interglacial periods.The work presented here shows that aerosols generated in southeastern Australia can travel to parts of West Antarctica and this is supported by atmospheric observations and models. In addition, evidence of Australian dust in Antarctic ice cores further implies dust deposition in the Southern Ocean would have occurred in the past. Current meteorological observations also imply that the western Pacific and Indian Ocean sector of the Southern Ocean would frequently receive aeolian dust components originating from southeastern Australia. |
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