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Zircon answers the age old question: Curtin



Researchers from Curtin University have studied the age of sand granules to understand more about the Earth’s ancient history than ever before.

By determining the ‘age distribution fingerprint’ of zircon minerals within the sand of beaches, rivers and rocks, the researchers could look back over the last few billion years of tectonic movement.

Lead researcher Milo Barnham said zircon was particularly good at storing information over such periods.

“While much of the original geological record is lost to erosion, durable minerals like zircon form sediments that effectively gather information from these lost worlds to paint a vivid picture of the planet’s history, including changing environments, the development of a habitable biosphere, the evolution of continents, and the accumulation of mineral resources at ancient plate boundaries,” he said.

The full research paper, Understanding ancient tectonic settings through detrital zircon analysis, was published in the journal Earth and Planetary Science Letters and can be found online here.

The paper’s introduction outlined previous issues with attempts to date back this far.

“Resolving the tectonic setting of sedimentary basins becomes increasingly difficult further back in time due to the increasing likelihood of overprinting by younger tectonomagmatic and metamorphic processes,” the report stated.

Burham explained why the new technique can mitigate these previous issues.

“The way the Earth recycles itself through erosion is tracked in the pattern of ages of zircon grains in different geological settings,” he said.

“For example, the sediment on the west and east coasts of South America are completely different because there are many young grains on the west side that were created from crust plunging beneath the continent, driving earthquakes and volcanoes in the Andes.

“Whereas, on the east coast, all is relatively calm geologically and there is a mix of old and young grains picked up from a diversity of rocks across the Amazon basin.”

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