Sydney, May 31 (IANS) The similarity of Australia’s Red Centre with Mars geologically may help explain why the country holds the world’s largest deposits of opal, a gemstone, researches at the University of Sydney have said.
Red Centre refers to Uluru, the massive red chunk of rock, three-km-long and 350 metres high, located in central Australia.
“Many Australians familiar with the unmistakable features of the Red Centre may not realise, despite their similarly and the striking red appearance, that it shares many of its remarkable characteristics with Mars,” says Patrice Rey, associate professor of geosciences from the University of Sydney.
Notably, opaline silica, iron oxides and clay minerals similar to those found in central Australia were discovered on Mars surface in 2008, where they were interpreted as the product of acid weathering of volcanic debris covering the red planet, the Australian Journal of Earth Sciences reports.
“Australia produces over 90 percent of the world’s supply of opal. Before this, we did not know its origin, why it forms at such shallow depths or why it can be found in central Australia and almost nowhere else on the Earth,” says Rey.
“The formation of Australian opal was due to an extraordinary episode of acidic weathering, during the drying out of the central Australian landscape,” says Rey, according to a release of Sydney University.
This occurred when the Eromanga Sea, a vast body of water covering 60 percent of Australia, extending from Coober Pedy to the Carpentaria Basin and across to Lightning Ridge, started retreating.
Between 100 million and 97 million years ago, this sea came to cover a much smaller area. This meant the previously inundated central Australian landscape started drying out and acidic weathering happened on a massive scale.
Acidic weathering in central Australia is unique on the Earth at that scale, covering an estimated 1.3 million square km, but it has been described at the surface of Mars.
“The USA and the European community have invested billions of dollars to send orbiters and rovers to Mars in the hope of finding extra-terrestrial life, but Central Australia offers a unique natural laboratory where potential Martian bio-geological processes could be studied,” concludes Rey.