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Research from Curtin University has uncovered that a significant meteorite impact occurred in northwestern Scotland approximately 200 million years later than earlier estimates, fundamentally changing the narrative of Scotland’s geological history and enhancing our understanding of the development of non-marine life on Earth.
Once thought to have taken place around 1.2 billion years ago, this impact is responsible for the formation of the Stac Fada Member, a crucial rock layer that provides essential insights into Earth’s ancient history, including the potential effects of meteorite strikes on the planet’s environment and the evolution of life.
Lead researcher Professor Chris Kirkland, associated with Curtin’s Frontier Institute for Geoscience Solutions in the School of Earth and Planetary Sciences, noted that the team utilized minute zircon crystals as geological ‘time capsules’ to accurately date the event to 990 million years ago.
“These tiny crystals captured the precise moment of the impact, with some even converting into a rare mineral known as reidite, which forms under extreme pressure,” explained Professor Kirkland.
“This provided irrefutable evidence linking the meteorite strike to the Stac Fada deposit.
“When a meteorite collides with Earth, it can partially reset the atomic clocks within zircon crystals. These ‘damaged timepieces’ are typically difficult to date, but we developed a model to reconstruct the timing of the disturbance, confirming the impact at 990 million years ago.”
Professor Kirkland pointed out that this event coincided with the rise of some of the earliest freshwater eukaryotes, the ancient forerunners of plants, animals, and fungi.
“The new timeline indicates that these life forms in Scotland emerged around the same period as the meteorite impact,” he noted.
“This raises intriguing questions about whether substantial impacts might have influenced environmental conditions, thereby affecting early ecosystems.
“Although the impact crater itself has not yet been found, this research has gathered additional clues that could help pinpoint its location.
“Comprehending the timing of meteorite impacts allows us to investigate their possible effects on Earth’s environment and the diversification of life beyond aquatic habitats.”
This study was conducted in partnership with NASA Johnson Space Center, the University of St. Andrews, the University of Portsmouth, and Carl Zeiss Microscopy Ltd.
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