A research team has uncovered an unexpected presence of helium-3, a rare isotope of helium, in volcanic rocks on Baffin Island, Canada. This discovery adds support to the theory that helium-3 has been slowly leaking from the Earth’s core for millennia.
Helium-3, unlike its more common counterpart helium-4, is relatively scarce on Earth but is more prevalent in the wider universe. Scientists were surprised to find a significant amount of helium-3 within the Baffin Island rocks. The study detailing this finding was recently published in the journal Nature.
Lead study author Forrest Horton, an associate scientist in the department of geology and geophysics at the Woods Hole Oceanographic Institution, explained that helium-3 is rare on Earth because it has not been added to the planet in significant quantities and is continually lost to space as Earth’s rocky mantle convects and circulates.
The presence of elements that escape from the Earth’s core provides valuable insights into the planet’s formation and evolution. This new discovery lends support to the existing theory that Earth originated within a solar nebula, a cloud of gas and dust likely triggered by a nearby supernova explosion, which contained helium-3.
The researchers conducted their study on Baffin Island in 2018, exploring the lava produced millions of years ago when Greenland and North America separated, forming new seafloor. The volcanic rocks on the island contained higher levels of helium-3 and helium-4 than previously reported in similar research.
Horton and his team collected samples in this remote and striking Arctic landscape, with the help of local organizations, including the Qikiqtani Inuit Association and Nunavut Research Institute, who provided protection from polar bears and essential access to the region.
Helium-3, which is incredibly rare on Earth, was measured at approximately 10 million atoms per gram of olivine crystals, while there is typically just one helium-3 atom for every million helium-4 atoms.
The helium-3 likely originated from the solar nebula, which was formed during the big bang and eventually led to the creation of our solar system. As the solar nebula collapsed due to a nearby supernova, the materials within it formed the sun and planets, with helium-3 becoming locked in Earth’s core. Over time, this helium-3 has been slowly leaking from the core, ascending to the surface through magma plumes and eventually solidifying within olivine crystals before being discovered in the volcanic rocks of Baffin Island.
This research supports the notion that helium-3 has been escaping from the Earth’s core for a substantial period, although the precise timing remains uncertain. The helium-3 leak does not have any adverse effects on Earth, as it does not chemically interact with other substances.
The next phase of the research will focus on investigating whether the Earth’s core stores other light elements, potentially explaining the Earth’s outer core’s lower density than expected. Horton and his team are eager to explore potential connections between helium and other light elements, offering insights into planetary evolution and habitability.