5. North Western Dunefields and Plains (DP)
5.2.1 - Parabolic dunes and sandplains (dominant in west and central Big Desert)
5.2.2 - Linear dunes and sandplains (Little Desert, Sunset Desert and eastern Big Desert)
|Weathered Parilla Sand was redistributed during Quaternary arid periods to form the Lowan Sand of the siliceous dunefields which contain both linear and sub-parabolic dunes.|
The weathered Parilla sand escaped burial by lacustrine and fluviatile sediments in elevated areas, particularly on broad tectonic ridges such as the Pinaroo Block and the Millewa Ridge. These ridges appear to be the prime sources of Lowan Sand derived by wind stripping of the deep sands on the laterised profiles. The dunefields have migrated eastwards for great distances, for example from the Sunset Strip across a depression underlain by Blanchetown Clay for a distance of some 80 km.
Three clearly-defined tracts of Lowan Sand, the Big Desert, the Little Desert and the Sunset Desert extend eastwards from South Australia. The smallest, the Little Desert is about 25 km wide, and extends as far as the Wimmera River. The largest, the Big Desert, is almost 100 km wide along the border, narrowing towards the east. To the east of Outlet Creek and the Wirrengren Plain which marks the termination of the Wimmera River, the Big Desert splits into two arms enclosing calcareous dunefields. The northern arm reaches almost to Lake Tyrrell. The Sunset Desert, 35 km wide at the border, also narrows towards the east where it almost reaches the Hattah Lakes.
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Hills, S.M. and Bowler, J. M. 1995. Linear dunes at Wilson’s Promontory and south-east Gippsland, Victoria: relict landforms from periods of past aridity. Proc. Royal Soc. of Victoria. Vol 107, pp 73-81
Related information on VRO
Silicous dunefields - 1963 air photo