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By firing lasers finer than a human hair at tiny grains of a mineral extracted from beach sand, Curtin researchers have found evidence of an almost four billion-year-old piece of the Earth鈥檚 crust that lies beneath the South-West of WA.

In a new finding that helps explain the planet鈥檚 evolution from uninhabitable to life supporting, lead researcher and PhD student Maximilian Droellner, from the Timescales of Mineral Systems Group within Curtin鈥檚 School of Earth and Planetary Sciences, said the lasers were used to vaporise portions of individual grains of the mineral zircon and revealed where the grains were originally eroded from, as well as the geological history of the region.

鈥淭here is evidence that an up to four billion-year-old piece of crust about the size of Ireland has been influencing the geological evolution of WA for the past few billions of years and is a key ingredient of rocks formed in WA across this time,鈥� Mr Droellner said.

鈥淭his piece of crust has survived multiple mountain-building events between Australia, India and Antarctica and appears to still exist at tens of kilometres of depth under the South-West corner of WA.

鈥淲hen comparing our findings to existing data, it appears many regions around the world experienced a similar timing of early crust formation and preservation.

鈥淭his suggests a significant change in the evolution of the Earth some four billion years ago, as meteorite bombardment waned, crust stabilised and life on Earth began to establish.鈥�

Research supervisor Dr Milo Barham, also from the Timescales of Mineral Systems Group within Curtin鈥檚 School of Earth and Planetary Sciences, said no large-scale study of this region had been done before and the results, when compared with existing data, had revealed exciting new insights.

鈥淭he edge of the ancient piece of crust appears to define an important crustal boundary controlling where economically important minerals are found,鈥� Dr Barham said.

鈥淩ecognising these ancient crustal remnants is important for the future of optimised sustainable resource exploration.

鈥淪tudying the early Earth is challenging given the enormity of time that has elapsed, but it has profound importance for understanding life鈥檚 significance on Earth and our quest to find it on other planets.鈥�

Mr Droellner, Dr Barham and research co-supervisor Professor Chris Kirkland are affiliated with The Institute for Geoscience Research (TIGeR), Curtin鈥檚 flagship Earth Sciences research institute and the research was funded by the Minerals Research Institute of Western Australia.

The full research paper, 鈥�A persistent Hadean鈥揈oarchean protocrust in the western Yilgarn Craton, Western Australia鈥� was published in journal聽Terra Nova聽and can be found online聽.