Scientists have discovered an ancient piece of Earth’s crust 4 billion years old under Western Australia

The laser paves the way for finding old crust.

Curtin University Researchers have discovered evidence of a nearly four-billion-year-old piece of Earth’s crust beneath southwestern Western Australia by using lasers smaller than a human hair to target microscopic grains of mineral extracted from beach sand.

The Timescales of Mineral Systems Group at the Curtin School of Earth and Planetary Sciences, led by Ph.D. The laser was used to vaporize fragments of individual grains of the mineral zircon and revealed where the grains were originally eroded as well as the geological history of the area, said student, Maximilian Droelner. This new discovery helps explain how the planet evolved from being uninhabitable to supporting life.

“There is evidence that a four-billion-year-old piece of crust the size of Ireland has influenced the geological evolution of Western Australia over the past few billion years and is a major component of rocks formed in Washington during this time,” says Mr Drollner.

“This piece of crust has survived multiple mountain-building events between Australia, India and Antarctica and appears to be still present at a depth of tens of kilometers below the southwestern corner of Western Australia. When comparing our findings with existing data, it appears that many areas Around the world, similar timing has been observed for early crust formation and preservation. This indicates a significant change in Earth’s evolution about four billion years ago, as meteorite bombardment waned, crust settled and life began to establish.”

Research supervisor Dr Milo Parham, also of the Timescales of Mineral Systems Group within the Curtin 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, showed intriguing. New insights.

“The edge of the ancient piece of crust appears to mark important crustal boundaries that control where to find economically important minerals,” said Dr. Parham.

“Identification of ancient crustal remnants is important for the future of optimal exploration of sustainable resources. Studying the early Earth is challenging due to the sheer amount of time that has passed, but it is of profound importance to understanding the importance of life on Earth and our quest to find it on other planets.”

Reference: “Paleolithic Steadfast Plantation in West Yelgarn Craton, Western Australia” by Maximilian Drollner, Christopher L. Kirkland, Milo Parham, Noreen J. Evans and Bradley J. MacDonald, 17 June 2022, Available here. Terra Nova.
DOI: 10.1111 / ter.12610

Mr. Droelner, Dr. Parham and research co-author Professor Chris Kirkland are affiliated with the Institute for Geosciences Research (TIGeR). Curtin’s flagship Earth Science Research Institute was funded by the Western Australian Institute of Mineral Research.