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Quartz gibber covering
Quartz Gibber Plain

Quartz Gibber Plain between Tibooburra and White Cliffs

Approximate Latitude -29.72, Longitude 142.61

Located in the Outback Region of NSW, nearest town White Cliffs

Link to Detailed Map

Gibber covered plains are a common site in outback NSW. Gibber is the word which describes a small rock or pebble which forms a pavement with similar rocks on the surface of desert landscapes.

The most common theory for their existence is that they are all that is left after the weathering processes of wind and sparse rain has removed everything else. Once the pavement has formed it protects the underlying soil from further weathering and as there is not much vegetation because of lack of rain the pavement stays intact.

The following information is quoted from: Desert pavement

The newest theory of pavement formation comes from careful studies of places like Cima Dome, in the Mojave Desert of California, by Stephen Wells and his co-workers. Cima Dome is a place where lava flows of recent age, geologically speaking, are partly covered by younger soil layers that have desert pavement on top of them, made of rubble from the same lava. Obviously the soil has been built up, not blown away, and yet it still has stones on top. In fact, there are no stones in the soil, not even gravel.

There are ways to tell how many years a stone has been exposed on the ground. Wells used a method based on cosmogenic helium-3, which forms by cosmic ray bombardment at the ground surface. Helium-3 is retained inside grains of olivine and pyroxene in the lava flows, building up with exposure time. The helium-3 dates show that the lava stones in the desert pavement at Cima Dome have all been at the surface the same amount of time as the solid lava flows right next to them. It's inescapable that in some places, as he put it in a July 1995 article in Geology, "stone pavements are born at the surface". While the stones remain on the surface due to heave, deposition of windblown dust must build up the soil beneath that pavement.

For the geologist, this discovery means that some desert pavements preserve a long history of dust deposition beneath them. The dust is a record of ancient climate, just as it is on the deep sea floor and in the world's ice caps.

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