Australia: The Land Where Time Began

A biography of the Australian continent 

Strzelecki Desert & Tirari Desert Timing of Linear Dune Activity

There are linear dunes covering more than 1/3 of the Australian continent, but it is only poorly understood when they formed. In this study Fitzsimmons et al. collected 82 samples from 26 sites across the Strzelecki and Tirari Deserts, located in the driest part of central Australia, to provide an optically stimulated luminescence chronology (OSL) of these dunefields. There are up to 4 stratigraphic horizons preserved in these dunes, bounded by palaeosols, which provide evidence of multiple reactivation periods that are punctuated by episodes during which there was increased environmental stability. Dune activity occurred in episodes about 73-65, 35-32, 22-18 and 14-10 ka. At other times intermittent partial mobilisation persisted throughout the last 75 ka and it appears dune activity intensified during the Late Holocene. At times when the sediment was available for transport dune construction took place; this coincided with conditions that were cold and arid in the Strzelecki and Tirari Deserts during Marine Isotope Stage (MIS) 4, late MIS 3 and MIS 2, and the warm dry climates of the late Pleistocene-Holocene period of transition and the Late Holocene. During the humid periods of MIS 5 localised influxes of sediment on active flood plains and the floors of lakes resulted in the formation of dunes. Widespread reactivate of dunes coincided with times of glaciation in southeastern Australia, along with cooler temperatures in the adjacent oceans and Antarctica.

Sources & Further reading

  1. Fitzsimmons, K. E., E. J. Rhodes, J. W. Magee and T. T. Barrows (2007). "The timing of linear dune activity in the Strzelecki and Tirari Deserts, Australia." Quaternary Science Reviews 26(1921): 2598-2616.

 

Author: M. H. Monroe
Email:  admin@austhrutime.com
Last Updated 01/02/2015
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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading