Ethabuka Reserve is a nature reserve in the north of the desert owned and managed by Bush Heritage Australia. Dunefields The extensive dunefields of the Simpson Desert display a range of colours from brilliant white to dark red, and include pinks and oranges. Morphology The sand ridges have a trend of SSE-NNW and continue parallel for great distances. This pattern is seen throughout the deserts of Australia. Some of the ridges continue unbroken for up to 200 km. The height and the spacing between the ridges are directly related. Where five to six ridges occur in 1 km, the dune height is around 15 m, but when only one or two ridges occur in 1 km, the height jumps to 35–38 m. In cross section, the lee side is the eastern slope with an incline of 34-38°, while the stoss side is the western slope with an incline of only 10-20°. In cross section, the cross beds are planar with foresets alternating between east and west. The foresets have incline angles of 10-30°. Sediment The sand is predominately made up of quartz grains, which are rounded and subangular. They range in size from 0.05 to 1.2 mm with 0.5 mm being the typical size for the crests and 0.3 mm being the average size on the dune flanks. The active crests have sand sediment, but on the interdunes, the sediment is not as well sorted. The sediment varies in color from pink to brick red, but by the rivers and playas, the sediment color is light grey. The progression of the color from grey to red is due to the release of iron oxide from the sediment when weathered. See also Australasian realm Ecoregions of Australia List of deserts by area Simpson Desert Important Bird Area References External links Trek notes for The Simpson Desert (ExplorOz) Aerial Video footage of the Simpson Desert Reading the Simpson Desert Into the Simpson Desert: Join veteran desert archaeologist Dr Mike Smith on an expedition into the remote southern Simpson Desert (2007) - includes audio blog, expedition slideshow and photo diary, National Museum of Australia Deserts of Australia Ergs Deserts of the Northern Territory Deserts of Queensland Deserts of South Australia Lake Eyre basin Central Queensland Far North (South Australia) Australian outback tracks Ecoregions of South Australia Ecoregions of Queensland Ecoregions of the Northern Territory IBRA subregions 1930s neologisms