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- Scientists have spotted high levels of a specific type of helium called ³He/⁴He in Arctic lava.
- This could suggest the Earth's core is "leaking" helium.
- The findings could upend what we knew about our planet's core, which was thought to be sealed away.
Earth's mysterious core is, once again, baffling scientists with its strange behavior.
A study of 62-million-year-old lava flows on Baffin Island in the Arctic Archipelago has found unusually high levels of helium-3 (³He), a rare isotope that is associated with the insides of our planet.
The study suggests the Earth's core may be leaking the rare helium, upheaving the belief that the giant ball of molten iron at the center of our planet is sealed away.
"I find this exciting because it suggests that the deep Earth is more dynamic than we realized," Forrest Horton, a geochemist at Woods Hole Oceanographic Institution and lead author on the study, told Vice's Motherboard.
A clue into the Earth's insides
When ³He is found trapped in rock, scientists tend to think it comes from material that was bombarded by the sun at the very beginning of our planet's history.
That's because Earth itself doesn't produce much ³He, and any ³He that escapes from Earth floats straight into space. Additionally, ³He that comes from solar radiation today bounces back to space thanks to our planet's magnetic field.
It follows that high levels of ³He found in rock today would have come from the birth of our planet.
Seeing ³He in rocks is not that uncommon — its level is measured as a proportion of ³He compared to another helium isotope found in rock, ⁴He. Scientists have traced most of the ³He-rich rocks back to the Earth's mantle.
What puzzled scientists in this latest study is just how much ³He was in the Baffin Islands lava olivine rocks.
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The ³He/⁴He ratio found in the Baffin Islands should not be possible
The Earth's mantle isn't static. It's constantly spewing lava to the surface, and gobbling up pieces of the Earth's crust. With all that churning, some of the isotope originally preserved inside the planet has escaped over time.
However, scientists say there's a limit to how much ³He can be found in a rock that comes from the mantle. Anything above that limit likely means the helium originates from elsewhere.
"What was surprising was that we measured ³He/⁴He ratios that extend to much higher values than previously thought," Horton said.
The next logical assumption then, is an even more challenging one: the rock comes from deeper within — meaning the core. That, in itself, could rewrite what we know about our planet.
"Traditionally, the core and outer layers of our planet (mantle and crust) were presumed to be geochemically isolated (i.e., material does not transfer back and forth)," Horton told Vice in an email.
The finding, Horton told Vice, "lends credence to the idea that material, or at least helium, leaks out of the core."
"I find this exciting because it suggests that the deep Earth is more dynamic than we realized: elements move between the metallic and rocky parts of our planet," he said, per Vice.
"One important question is, assuming helium is leaking out of the core, whether any other elements also escape from the core? And when did these elements migrate into the rocky part of the planet?" he said.
The findings were published in the peer-reviewed journal Nature on August 30.