An unprecedented discovery of elevated helium-3 to helium-4 ratios in ancient lava flows on Baffin Island, Canada, suggests that these rare isotopes may be leaking from Earth’s core. Published on October 18, 2023, the groundbreaking study led by geochemist Forrest Horton of the Woods Hole Oceanographic Institution opens new avenues for understanding Earth’s deepest regions and its formative history.
Scientists led by geochemist Forrest Horton of the Woods Hole Oceanographic Institution have made a discovery that could significantly alter our understanding of Earth’s interior. The team found that ancient lava flows on Baffin Island, a large landmass in Canada’s Arctic Archipelago, contain the highest ratios of helium-3 (3He) to helium-4 (4He) ever recorded in terrestrial volcanic rocks. Published in the journal Nature on October 18, 2023, these findings may point to the Earth’s core as the source of these rare helium isotopes.
Earlier research had detected trace elements of helium-3 in lava flows on Baffin Island. However, the levels observed by Horton’s team are unparalleled, exceeding those found in any previous studies. The team’s data revealed much higher levels of helium-3, as well as an unprecedented 3He/4He ratio, strengthening the hypothesis that the Earth’s core may be leaking this ancient isotope.
Helium-3 is a rare isotope that was prevalent during the Earth’s formation and became trapped in its core. Its presence on the Earth’s surface is typically fleeting, as it soon escapes into the atmosphere and vanishes into space. Therefore, finding high levels of helium-3 in terrestrial sites is significant. The researchers assert that if helium-3 is indeed emanating from the core, it opens a new frontier in studying Earth’s deepest and most enigmatic region.
The ramifications of this discovery extend beyond helium isotopes. According to Horton, if helium-3 is leaking from the Earth’s core, other core materials are likely seeping out as well. This provides scientists with an unprecedented opportunity to physically examine core substances, something hitherto considered impossible.
In an email to Motherboard, Horton stated, “The high 3He/4He in these lavas make them especially important for understanding Earth’s formation and its deep interior.” He added that the elevated ratios provide valuable insights into the planetary accretion and evolution processes, which was the motivation behind reassessing the Baffin Island lavas.
Furthermore, the discovery suggests that Earth’s core may have retained helium isotopes even through cataclysmic events like the Moon-forming giant impact, which is believed to have melted and mixed all of the rocky material on Earth. This lends support to the idea that the Earth’s deep interior is more dynamic than previously assumed, with elements potentially moving between its metallic and rocky parts.
The study serves as a cornerstone for future research into Earth’s core and raises the possibility that our planet’s interior is far more active and complex than once believed.
1 Highest terrestrial 3He/4He credibly from the core – F. Horton et al. – Nature – October 18, 2023 – DOI https://doi.org/10.1038/s41586-023-06590-8
Featured image: Baffin Island, Canada. Credit: NASA
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