Curtin finds first evidence meteorites created continents

By Liam McAneny

Researchers from Curtin University believe they have discovered the first hard evidence that Earth’s continents were formed by giant meteorite strikes.

Dr Tim Johnson led the study, which examined minerals from the Pilbara in Western Australia. The paper is set to be published in the journal Nature later this year.

The Pilbara region is home to the world’s best-preserved remnants of Earth’s ancient crust. It is not the first time that scientific studies of the region’s rocks have unearthed ancient secrets, with the oldest meteorite ever discovered on Earth found in the region.

“By examining tiny crystals of the mineral zircon in rocks from the Pilbara Craton in Western Australia … we found evidence of these giant meteorite impacts,” Johnson said.

“Studying the composition of oxygen isotopes in these zircon crystals revealed a ‘top-down’ process starting with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of giant meteorite impacts.”

The theory that Earth’s continents formed on the sites of huge meteor impacts have been around for decades, but there has been no supporting evidence.

“Our research provides the first solid evidence that the processes that ultimately formed the continents began with giant meteorite impacts, similar to those responsible for the extinction of the dinosaurs, but which occurred billions of years earlier,” said Johnson, who works at Curtin’s School of Earth and Planetary Sciences.

The research conducted by the team will provide useful information about the continued evolution of the earth’s continents.

Johnson said that this was crucial given that the continents are home to most of Earth’s biomass and vital mineral deposits.

Johnson’s team is keen to expand their research and continue to test their model across other regions.

“Data related to other areas of ancient continental crust on Earth appears to show patterns similar to those recognised in Western Australia. We would like to test our findings on these ancient rocks to see if, as we suspect, our model is more widely applicable.”

The work being performed by the team also has useful implications for extraterrestrial planetary science, providing scientists with more in-depth knowledge about the consequences of meteorite impacts and continental formation.

 

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