Australia Formed by Three-Continent Collision
SYDNEY The island continent of Australia was once three continents which collided 1.64 billion years ago, a new study has found, prompting speculation of new mineral deposits in the outback.
"Northern, western and central Australia all belonged to different continents," said Kate Selway, author of the study.
"If you looked south from Alice Springs (in central Australia) before 1.64 billion years ago, you would have seen an ocean," Selway said in a statement on Thursday.
"The huge forces involved in this collision produced volcanoes which actually helped create the crust of central Australia," she said.
Selway, a PhD student supervised by two professors from the University of Adelaide, said probing the Earth beneath central Australia uncovered a collision zone.
Using a geophysical technique called magnetotellurics allowed her to penetrate sediment along the border of the three previous continents and measure the electrical conductivity of the Earth up to hundreds of kilometres below the surface.
The study found northern Australia was more conductive than central Australia and that the boundary between the two areas extended to at least 150km (93 miles) in depth.
Selway said her findings mean there could be new mineral deposits where the former separate continents joined to form Australia. Central Australia's main minerals include copper, uranium (Olympic dam) and opals.
"Not only does this kind of information help us to understand how our continent formed it can also be fundamental in finding the next big mineral deposit," she said.
"Such structures play an important role in determining how fluids move under the surface and it is these fluids which often carry the metals that can concentrate into valuable mineral deposits."