Australian desert dune fields initiated with Pliocene–Pleistocene global climatic shift
- 1Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia
- 2Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
- 3Department of Environmental and Geographical Sciences, Manchester Metropolitan University, Manchester M1 5GD, UK
Abstract
Development of continental aridity has been linked to late Cenozoic global cooling, but the evidence is indirect, based on terrestrial loess deposits and eolian silt in marine sediments, whereas direct dating of the inception of arid landforms has been frustrated by a lack of suitable methods. Here we report the first age determination of a major arid-zone dune field, based on cosmogenic 10Be and 26Al measurements of drill cores from dunes in the Simpson Desert, central Australia. Results show that the dune field began to form ca. 1 Ma, whereas dating using quartz optically stimulated luminescence indicates episodic dune building during late Quaternary ice ages. Less intense desertification began earlier; the previous cosmogenic exposure dating showed that neighboring stony deserts began to form at the onset of Quaternary ice ages 2–4 Ma. Aridity deepened and the dune field formed when ice age cycles increased their amplitude and switched their periods from 40 k.y. to 100 k.y. ca. 1 Ma.
Footnotes
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↵*Current address: Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia; E-mail: toshiyuki.fujioka{at}anu.edu.au.
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↵GSA Data Repository item 2009012, details of cosmogenic nuclide and optically stimulated luminescence analyses, and of the multistage dune formation model discussed in text, Table DR1 (sequential depth profiles used for model calculation), Table DR2 (sequential depth profiles used for model calculation), Figures DR1 and DR2 (typical OSL decay and growth curves in this study), and Figure DR3 (equivalent dose measurement for a sample with a mixed dose population), is available online at www.geosociety.org/pubs/ft2009.htm, or on request from editing{at}geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.
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- Received 28 April 2008.
- Revision received 3 September 2008.
- Accepted 15 September 2008.
- © 2009 Geological Society of America
