• The Stac Fada meteorite impact in Scotland is now dated to 990 million years ago, revising previous estimates of 1.17 to 1.2 billion years.
• The revised dating aligns the impact event with early non-marine eukaryotic fossils and a major mountain-building event, potentially influencing the development of early microbial ecosystems.
• Scientists analyzed zircon crystals and reidite in the Stac Fada Member to refine the impact date, using uranium-lead decay and mathematical modeling.

Scientists have redated a significant meteorite impact that occurred in northwest Scotland to 990 million years ago. This revises previous estimates placing the event 200 million years earlier. The impact, which created the Stac Fada Member rock formation, now coincides with a period of early non-marine life, offering insights into how such events may have influenced the Earth's environment and the expansion of life beyond the oceans. The impact crater itself remains undiscovered, potentially buried beneath the Torridonian mountains or the North Atlantic Ocean.

• What: A meteorite impact occurred in northwest Scotland, creating the Stac Fada Member rock formation. The impact's date has been revised to 990 million years ago.
• Who: Researchers from Curtin University, the University of St Andrews, including Professor Chris Kirkland, Timmons Erickson, and Tony Prave.
• When: The meteorite impact occurred 990 million years ago, a revision from the previously estimated 1.17 to 1.2 billion years ago. The study was published in the journal Geology on April 28.
• Where: The impact site is located in northwest Scotland. The impact crater's location is currently unknown but may be under the Minch or the Torridonian mountains.

The redating of the Stac Fada meteorite impact is significant because it aligns the event with a period of early non-marine eukaryotic fossils and a major mountain-building event. This suggests a potential influence of the impact on the environmental conditions and the evolution of early microbial ecosystems. The use of zircon crystals and reidite to determine the age of the impact provides a more accurate timeline for understanding Scotland's ancient geology. The impact's influence on Earth's environment and the expansion of life beyond the oceans are important areas of future research.

When a meteorite hits, it partially resets the atomic clocks inside the zircon crystals and these ‘broken timepieces’ are often unable to be dated but we developed a model to reconstruct when the disturbance occurred, confirming the impact at 990 million years ago.

Those environments (rivers, lakes, estuaries) contained well-established microbial ecosystems. Thus the region provides a natural laboratory to examine what microbial ecosystems and their habitats were like before the impact and, importantly, how they recovered following that dramatic event.

The redating of the Stac Fada meteorite impact to 990 million years ago provides a refined understanding of Scotland's ancient geological history and its potential influence on early life. While the exact location of the impact crater remains unknown, the revised timeline offers new avenues for exploring the impact's role in shaping Earth's environment and the evolution of early ecosystems. Ongoing research will likely focus on locating the crater and further investigating the impact's effects on microbial life.