A recent analysis of ancient lava flows in the Canadian Arctic has provided intriguing evidence challenging current scientific understandings of Earth’s internal dynamics. The study suggests that helium, trapped within the Earth’s core since its formation over 4.5 billion years ago, might gradually seep into the mantle and reach the surface.
This discovery, led by geochemist Forrest Horton from the Woods Hole Oceanographic Institution, supports the hypothesis that primordial helium reservoirs have been preserved in the core since the early stages of Earth’s existence.
By examining 62-million-year-old lava flows on Baffin Island in the Canadian Arctic, the researchers found helium isotopic ratios significantly higher than those observed in other rocks on Earth. Specifically, helium-3 levels were 65 to 69 times higher than the atmospheric ratio, suggesting a unique source. Previous studies had already detected elevated helium-3 levels in volcanic rocks globally, but the Baffin Island lavas exhibited ratios twice as high as any other location, sparking new theories.
The unexpected findings indicate that the helium may originate not from the mantle but from an even deeper source—the Earth’s core. The lavas also contained other elements, such as neon, with isotopic ratios suggesting a potential core origin. This discovery raises questions about Earth’s formation and planetary evolution, challenging previous assumptions about the movement of primordial gases within the planet.
Horton proposes a mechanism where helium gradually leaks from the outer core into the mantle before rising in a buoyant plume of rock, eventually erupting on the surface as lava. This scenario gives scientists a rare glimpse into the processes occurring at the boundary between Earth’s core and mantle, nearly 3,000 kilometers beneath the surface.
While these findings offer compelling evidence, scientists remain cautious, acknowledging uncertainties about the helium’s precise origin. The study contributes valuable insights into the Earth’s geological history and the dynamics of noble gases but does not definitively resolve the debate within geochemistry on the origin of Earth’s helium and other inert gases.
The discovery of helium with distinct isotopic ratios challenges existing theories, providing a fresh perspective on Earth’s inner workings and emphasizing the complexity of the planet’s geological evolution. Further research will be crucial to refine these theories and deepen our understanding of the deep processes shaping our planet.