Helium Leak: Earth’s Core Could Be Releasing Gas into the Mantle
A Surprising Discovery Challenges Our Understanding of Earth’s Inner Workings
Scientists have made a fascinating discovery in the Canadian Arctic that suggests helium from Earth’s core might be slowly leaking into the mantle and eventually reaching the surface. This finding challenges our current understanding of the planet’s inner workings and sheds light on the origins of helium and other elements.
Trapped Gases from Earth’s Formation
According to the study’s lead author, geochemist Forrest Horton, the analysis of ancient lava flows in the Canadian Arctic indicates that gases from Earth’s formation are preserved deep within the planet. These gases, including helium, were trapped in Earth’s core when the young sun and protoplanets formed more than 4.5 billion years ago.
Isotopes and Origins
Helium can be distinguished by the number of neutrons in its nucleus, which determines its isotope. Helium-3, a rare isotope on Earth, was created during the big bang and in stars. On the other hand, helium-4, the most common isotope on Earth, forms through the natural radioactive decay of uranium and thorium in our planet’s interior.
Unprecedented Findings in the Canadian Arctic
In a groundbreaking study published in Nature, Horton and his colleagues examined 62-million-year-old lava flows in the east of Baffin Island. These lavas contained helium with an exceptionally high ratio of helium-3 to helium-4, suggesting a source deeper than the mantle.
While volcanic rocks from other hotspots around the world also exhibit elevated isotopic helium ratios, the Baffin Island lavas had ratios twice as high as any other location. This led the researchers to propose that the helium originated from Earth’s core rather than the mantle.
A Journey from the Core to the Surface
Horton suggests that the primordial gas could have leaked from the outer parts of Earth’s core into the neighboring mantle. From there, it could have risen in a buoyant plume of rock within the mantle, eventually erupting on the surface as lava. This process would provide valuable insights into the boundary between Earth’s core and mantle, nearly 3,000 kilometers beneath our feet.
Implications for Earth’s Evolution
The discovery of helium leakage from the core could reshape our understanding of Earth’s evolution. It suggests that during the early stages of the planet’s formation, helium and other gases were abundant in the rocky mantle. However, convective mixing within the mantle likely caused the loss of most of the initial helium, resulting in a more thoroughly mixed mantle than previously believed.
Debate and Uncertainty
While the study provides compelling evidence for helium leakage from the core, there is still ongoing debate within the field of geochemistry. Some experts question whether the noble gases, including helium, originated from primordial reservoirs or were added later through irradiation by the solar wind or helium-bearing meteorites.
Geochemist Cornelia Class from Columbia University considers the study to be “very good evidence” for helium leakage from the core. However, Manuel Moreira from the University of Orléans in France remains more cautious, stating that the proposition of helium storage and leakage from the core remains speculative.
As scientists continue to explore this fascinating phenomenon, the discovery of helium leakage from Earth’s core opens up new avenues for understanding our planet’s inner workings and the formation of other celestial bodies.
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