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Australia: The Land Where Time Began |
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Gibber Plains The name 'gibber' comes from the Aboriginal word for stone. It is very appropriate for the gibber plains, none more so than Sturt's Stony Desert. It is believed by some to be the most inhospitable place in Australia. In 1845 Sturt spoke of 'heating and parching blasts' as he walked across it. On other continents there are different names for this type of formation. The gibber is what is left when the sand and dust are blown away by the desert winds. Blowing sand polishes and smooths the stones and gravel. A stone shaped by windblown sand is called a ventifact. In many places the gibbers have a desert varnish, a veneer of iron- or silica-rich material. When dry, the gibber plains are hard surfaced, but after rain the spongy nature of the soil beneath the gibbers is apparent when it becomes muddy. Desert varnish is the thin iron oxide coating of the stones that has been polished by the blowing sand and dust. Uplands such as the Flinders Ranges and MacDonnell Ranges are bordered by stony (gibber) deserts, where exposed resistant rock, typically quartz, though in places it can be limestone, has been broken down to the size of gravel. On the western side of the Flinders Ranges the plains are covered with cobbles and gravel of quartz and limestone originating from the adjacent high country. Unlike quartz and limestone, the weathered product of granite is usually sand, that doesn't form protective coverings because of its small particle size. Of the major plains areas of the Australian arid zone 3 areas in particular have developed a covering of stones In the Gibson Desert, Sturt's Stony Desert
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |