Meteorite impact reshapes understanding of early life in Scotland

New research led by the University of St Andrews and Curtin University has revealed that a significant meteorite impact took place in north-west Scotland 990 million years ago, much later than the previously estimated 1.2 billion years ago. This impact formed what is known as the Stac Fada Member, a distinct layer of rock found in parts of the Scottish Highlands. The study utilized zircon crystals found in rocks to establish a more accurate dating of the event, which coincided with the emergence of freshwater eukaryotes, the ancient predecessors of various life forms such as plants, animals, and fungi. The timing of the meteorite impact raises intriguing questions about its potential influence on early ecosystems. Prof Chris Kirkland of Curtin University indicated that the new timeline suggests the arrival of these life forms in Scotland closely followed the meteorite strike. This correlation leads scientists to hypothesize that significant meteoritic impacts may have altered environmental conditions, which could impact the development of early life. The possibility of large impacts causing sweeping ecological changes has been a subject of interest among researchers, as it links cosmic events with terrestrial biological evolution. Prof Tony Prave from the University of St Andrews contributed insights into how the impact transformed the landscape, which was already shaped by rivers and thriving microbial ecosystems. Unlike ordinary impact events that obliterate the surface and create deep craters, the unique features of the Stac Fada Member offer valuable data regarding not only the strike itself but also the original land surface prior to the impact. This record provides crucial evidence of how those ancient ecosystems existed and subsequently recovered from a catastrophic event. Currently, the actual impact crater has not been located, yet the study has compiled additional clues that may lead to its discovery. Collaborations with NASA Johnson Space Center and the University of Portsmouth have enhanced the research effort, compounding the potential for further understanding of both the impact's immediate consequences and its long-term implications for life's development on Earth.