Talk:Deserts of Australia

Latest comment: 6 months ago by HiLo48 in topic 40% dunes ?!


The Pinnacles Desert edit

The Pinnacles Desert; shouldn't be added? 89.211.185.69 (talk) 20:06, 27 January 2009 (UTC)Reply

Painted Desert, Little Sahara (Kangaroo Island), Sandy Desert Nat. Park near to Victoria (not a real desert, but arid climate)? Btw. the area of the Great Victoria Desert in the table is diff. from the article. RIMOLA (talk) 23:45, 16 November 2011 (UTC)Reply

Nullarbor plain edit

Is not entirely a desert - unless there might be an authoritative WP:RS that says otherwise SatuSuro 08:40, 2 January 2010 (UTC)Reply

"Central Desert"?? edit

I tagged this one for discussion, as it doesn't seem to be a common name (per Google) and/or is poorly-defined: eg, the Central Desert Shire is in NT, and there's an old reference to a Great Central Desert in south central Australia, apparently now called the Tirari Desert in SA (Lake Eyre area. ???? --Pete Tillman (talk) 19:46, 25 July 2010 (UTC)Reply

bunyip edit

I just looked up "bunyip" and "drop bear" through Google... looks like someone is having a bit of fun here, as these are mythical creatures, like a jackalope or Bigfoot. That should probably be edited. 108.66.122.193 (talk) 18:05, 7 May 2013 (UTC)N. HallReply

Copy-edit needed edit

In § Regions, the following para needs clean-up:

A large contiguous desert area is formed by the Tanami, Greater Sands, Lesser Sands, Gibson and Greater Victoria Sands in western Australia and a smaller one by the Simpson, Sturt, Strzelecki and Tirari Deserts in the east. Spatially isolated between Great Victoria Sand and Simpson lies the small Pedirka Desert, which spreads out over the geological Pedirka Sedimentary Basin. The Small Sandy Desert connects to the Great Sandy Desert and is similar in terms of landscape and vegetation. The Western Desert, which describes a cultural region of Australia's indigenous people, includes the Gibson, Great Victoria, Great Sand and Small Sand deserts in the states of Northern Territory, South Australia and Western Australia.

Most of the ...

yoyo (talk) 09:21, 17 June 2023 (UTC)Reply

40% dunes ?! edit

The sentence in the second paragraph "About 40% of Australia is covered by dunes." is surely not true.

Is it meant to be 40% of the Australia deserts are dunes? Even that sounds high.

I don't have access to the reference to check it.

Quarrel (talk) 13:08, 30 September 2023 (UTC)Reply

So, I was bothered by this, so found the source:

Dunes cover approximately 40% of the surface area of Australia, constituting 38% of the world’s dune fields (Wasson et al. 1988). Most dunes are of simple longitudinal form, up to 300 m in length and 10–35 m in height, with an average interdune spacing of 160–2000 m. They form an anticlockwise whorl at the scale of the continent (Fig. 2.15), largely reflecting modern wind directions (Jennings 1968; Brookfield 1970; Wasson et al. 1988). The general trend in dune orientation is thought to reflect the response of winds to the subtropical high-pressure system, which determines airflow in Australia (Brookfield 1970). Dunes of the Strzelecki and Simpson Deserts are markedly asymmetrical, with steeper eastern slopes, causing Rubin (1990) to suggest that they may be migrating slowly eastward over millenial timescales. However, Nanson et al. (1995) conclude that the dunes have not moved more than 100 m from their Pleistocene core. The color of the dune sand is pale adjacent to major rivers (Diamantina River and Cooper Creek) and, according to Wopfner and Twidale (1967), becomes redder and older downwind from sand sources. Wasson (1983a, 1983b) argues that the different sand colors are principally a result of provenance and are unrelated to dune age. The source of the dune sand varies according to location, but is mainly derived from the sedimentary basins underlying the different regions of the dune fi eld. Material was deflated from the floodplains of major rivers, salt lake systems, and weathered underlying sediments. The downwind transfer of material was not likely significant, as the grains lack surface features indicative of aeolian transport, and sand color, heavy mineral characteristics, and grain surface features change quickly along the dunes, suggesting localized sources (Pell et al. 2000). Both the timing of the onset of dune activity and the age of the dominant dune forms remain controversial. At the present time, divergent palaeoenvironmental reconstructions based on luminescence ages are difficult to reconcile. Wopfner and Twidale (1988, 1992) conclude that the large dune fields of the Simpson and Strezlecki Deserts are entirely Holocene in origin, resting on a Pleistocene substrate, with older phases of dune activity only present on the desert’s margins. Their OSL dates indicate that most dunes are younger than 2000 years and rest on a fluvial/lacustrine base of 36,000 years’ age (Twidale et al. 2001). Then again, other studies suggest that aeolian activity was widespread within the Pleistocene, including thermoluminescence dates of dune material from approximately 100 ka (Nanson et al. 1995) and 243 and 167 ka (Gardner et al. 1987). Lomax et al. (2003) found fluvial-lacustrine sediments in interdune corridors that were deposited at least 210 and 160 ka (OSL ages), and later alluvial sedimentation at between 69 and 75 ka. Subsequent aeolian activity occurred between 60 and 50 ka and a palaeosol, indicating moister conditions with vegetation cover, formed atop this unit and is in turn overlain by another aeolian sequence (28,000–35,000 years old). Loose aeolian sands at the top of the dunes are less than 5000 years old, probably reflecting aeolian remobilization of the dune field in the late Holocene. It appears likely that dune sediments deposited during the LGM, a phase of maximum aridity and high aeolian activity (Bowler & Wasson 1984; Shulmeister et al. 2004; Duller & Augustinus 2006), were totally reworked during a late Holocene phase.

So maybe I just don't understand dunes and shouldn't wander out of my area of expertise too much .. !
Quarrel (talk) 19:35, 30 September 2023 (UTC)Reply
Given the complexity of the explanation in that source, that sentence in the second paragraph is sloppy and unhelpful. This (very) amateur geologist knows that a lot of older dunes are no longer active, are in areas we wouldn't now call deserts, and are covered in vegetation. I don't think the 40% claim in the article is helpful without more detail, and picking which detail to include from the rather complex source material is not a job I'm volunteering for. HiLo48 (talk) 03:15, 1 October 2023 (UTC)Reply