Curtin University researchers have discovered evidence in southern Australian beach sand of material that originated from the sub ice rock of Antarctica, providing a better understanding of how these lands were once joined.
The research, published today in the journal Earth and Planetary Science Letters, investigated the characteristics of individual sand grains near Albany, in Western Australia, to prove they originally came from Antarctica but travelled to Australia over millions of years.
Lead author Professor Chris Kirkland, from the School of Earth and Planetary Sciences at Curtin University, said while theories differed about how sediment was transported from the once-adjacent landmasses of Antarctica and India to Australia, the new research suggested that these lingering traces of neighbouring continents are more common across parts of WA than currently realised.
“By analysing minerals in the sand, we created a unique fingerprint with which to track these grains as they moved through different positions in the Earth’s crust, and therefore reconstruct the transport pathway back to its origin,” Professor Kirkland said.
“A specific mineral in beach sand called zircon was sampled and then analysed at Curtin University, applying for the first time a novel analytical approach that combines three different age-dating techniques on the same individual zircon grain.
“This ‘triple-dating’ approach includes laser ablation mass spectrometry, which measures the age of the source material in the magma that formed the zircon crystal, as well as identifying when the original crystals that became the sand grains actually grew. Following this investigation, the zircon grains were measured for their helium gas content, which determined when the grains cooled on their way to the Earth’s surface.”
Co-author Dr Milo Barham, also from Curtin’s School of Earth and Planetary Sciences, said heavy mineral sands were an important industry in Western Australia, yet understanding the source of these sand grains had proved difficult.
“This new research offers a better understanding of the ultimate source and route travelled over great time by sand grains, particularly zircon, into modern and ancient beach environments,” Dr Barham said.
“In turn, these findings may offer insight into heavy mineral deposit generation and help with mineral exploration.”
The research was also co-authored by Dr Martin Danišík, from the John de Laeter Centre based at Curtin, and was a collaboration between the Curtin node of the Centre for Exploration Targeting and the John de Laeter Centre.
The research paper titled, ‘Find a match with triple-dating: Antarctic sub-ice zircon detritus on the modern shore of Western Australia,’ can be found online here.
