• A meteorite impact in northwest Scotland is now dated to 990 million years ago, based on new analysis of zircon crystals.
• The revised dating coincides with the existence of early non-marine eukaryotic fossils in the region, suggesting a possible link between the impact and the evolution of early life.
• The location of the impact crater remains unknown, potentially lying beneath the Torridonian mountains or the North Atlantic Ocean.

Scientists have redated a significant meteorite impact that occurred in northwest Scotland to 990 million years ago. Previously believed to have taken place 1.2 billion years ago, the new dating aligns with the existence of early microbial ecosystems in the area. The impact, which left behind the Stac Fada Member rock formation, is now understood to have potentially influenced the environmental conditions of early life on Earth. The exact location of the impact crater is still unknown, fueling ongoing research efforts.

• What: A meteorite impact in northwest Scotland that formed the Stac Fada Member rock formation. The impact's date has been revised from 1.2 billion to 990 million years ago.
• Who: Chris Kirkland (Curtin University), Timmons Erickson (Curtin University), Tony Prave (University of St Andrews), geologists and researchers studying the Stac Fada Member.
• When: The impact occurred approximately 990 million years ago, during the Precambrian period.
• Where: Northwest Scotland, specifically the Stoer Group in the Highlands. The impact crater's location is currently unknown, possibly under the Minch strait or the Torridonian mountains.

The redating of the Stac Fada meteorite impact has significant implications for understanding the early Earth environment and the evolution of life. The alignment of the impact with the existence of early non-marine eukaryotic fossils suggests a potential link between the two. While the impact would have initially created a hostile environment, it may have also provided long-term benefits by fracturing rocks, generating hydrothermal systems, and forming crater lakes that concentrated essential ingredients for life. The ongoing search for the impact crater is crucial for a more complete understanding of the event's scale and effects.

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.

While the impact crater itself has yet to be found, this study has collected further clues that could finally reveal its location. Understanding when meteorite impacts occurred helps us explore their potential influence on Earth’s environment and the expansion of life beyond the oceans. The revised dating suggests these life forms in Scotland appeared at a similar time to a meteorite impact. This raises fascinating questions about whether large impacts may have influenced environmental conditions in ways that affected early ecosystems.

The redating of the Stac Fada meteorite impact to 990 million years ago has rewritten a portion of Scotland's geological history and opened new avenues of inquiry into the relationship between meteorite impacts and the development of early life. While the impact's crater remains elusive, continued research into the Stac Fada Member and the surrounding region promises to yield further insights into this significant event and its lasting impact on our planet.