The research, detailed in the journal Earth and Planetary Science Letters, is based on an analysis of 21 asteroid craters from the ‘Ordovician’ impact spike period, which occurred around 466 million years ago.
The study reveals that these craters were created by large objects that were pulled from their orbits by an unknown force, leading to their collision with Earth. The team discovered that the craters were predominantly clustered in a narrow band near the equator.
This distribution prompted the researchers to theorise that an asteroid fragmented due to tidal forces, forming a debris ring around Earth similar to the rings seen around Saturn.
Key findings on ancient rings
In a report by The Independent, Tomkins stated that the material from the ring gradually fell to Earth over the years resulting in increased meteorite impacts recorded in the geological record. He further noted that layers in sedimentary rocks from this period contain unusually high amounts of meteorite debris, supporting the team’s hypothesis.
The positioning of the craters close to the equator can be attributed to the movement of continents due to plate tectonics. Tomkins and his team suggest that during the Ordovician period, the sites of these craters were all located near the equator.
Their study also incorporated previous research that identified a consistent meteorite signature in several limestone deposits from the same era, which were also once situated near the equator.
Role of ancient rings in climate change on Earth
The study suggests that these ancient rings may have had significant climate implications. The debris ring is believed to have blocked sunlight, contributing to a global cooling event known as the Hirnantian Icehouse. This cooling event aligns with the period of increased meteorite impacts, suggesting a possible connection between the ring and climate changes during that time.
Challenges and future implication of the study
While these findings provide a fresh perspective on Earth’s ancient history, Tomkins notes that more evidence is required to confirm this hypothesis. The study presents a novel twist in understanding Earth’s past, but additional research will be necessary to validate the impact of these ancient rings on Earth’s climate and geological history.
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