The Earth’s core may have been leaking helium for millions of years

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Scientists have discovered a surprising amount of a rare version of helium, called helium-3, in volcanic rock on Canada’s Baffin Island, supporting the theory that the noble gas is escaping from the Earth’s core — and has been for thousands of years.

The research team also discovered helium 4 inside the rocks.

While helium-4 is common on Earth, helium-3 can be found more easily elsewhere in the universe, which is why scientists were surprised to discover a larger amount of the element than previously reported from rocks on Baffin Island. A study describing the discovery was recently published in the journal nature.

“At a fundamental level, there is less 3He (helium-3) in the universe than 4He (helium-4),” said lead study author Forrest Horton, an associate scientist in the Department of Geology and Geophysics at Woods Hole Oceanographic Institution. , in an email.

Horton added: “3It is rare on Earth because it is not produced or added to the planet in large quantities and is lost to space.” “As the rocky part of the Earth moves and moves like hot water on a stovetop, the material rises, cools and sinks.
During the cooling phase, helium is lost to the atmosphere and then to space.

Discovering elements seeping from Earth’s core could help scientists unlock insights into how our planet formed and evolved over time, and the new findings provide evidence to support an existing hypothesis about how our planet came to be.

Baffin Island, located in the territory of Nunavut, is the largest island in Canada. It is also the fifth largest island in the world.

A high ratio of helium 3 to helium 4 was first discovered in volcanic rocks on Baffin Island by Solvi Lasse Evans as part of his doctoral studies under the supervision of scientist Finley Stewart of the University of Edinburgh. Their findings were published in Nature 2003.

The composition of a planet is a reflection of the elements that make it up Previous search It found that trace amounts of helium-3 leaking from Earth’s core support the popular theory that our planet originated in a solar nebula — a cloud of gas and dust that likely collapsed due to a shock wave from a nearby supernova — which contained the element.

Horton and his colleagues took it a step further when they did this He conducted research on Baffin Island in 2018, they study lava that erupted millions of years ago when Greenland and North America separated, making way for a new sea floor. They wanted to investigate rocks that might hold insights into the contents within the Earth’s core and mantle, the mostly solid layer of Earth’s interior beneath its surface.

Researchers traveled by helicopter to reach the island’s remote landscape, where lava flows form towering cliffs, giant icebergs float by, and polar bears stalk the coast. Local organizations, including the Qikiqtani Inuit Society and the Nunavut Research Institute, provided researchers with access, advice and protection from the bears, Horton said.

“This area on Baffin Island has special significance as sacred lands for local communities and as a scientific window into the depths of the Earth,” he said.

The Arctic rocks examined by Horton and his team revealed surprisingly higher measurements of helium-3 and helium-4 than previous research had reported, and the measurements varied between the samples they collected.

“Many of the lavas are full of bright green olivine (also known as peridot), so breaking off fresh pieces with a rock hammer was as exciting as taking apart a geode as a child: each rock was a treasure to be discovered.” Horton said. “And what scientific treasures it turns out to be!”

Only one helium-3 atom exists for every million helium-4 atoms, Horton said. The team measured about 10 million helium-3 atoms per gram of olivine crystals.

“Our high 3He/4He measurements indicate that the gases, which were presumably inherited from the solar nebula during the formation of the solar system, are better preserved on Earth than previously thought,” he said.

But how did helium-3 end up in rocks in the first place?

The answer may begin with the Big Bang, which also released an abundance of hydrogen and helium when it created the universe. These elements have been incorporated into the formation of galaxies over time.

Scientists believe that our solar system formed 4.5 billion years ago inside a solar nebula. As the dust cloud collapsed in a supernova, the resulting material formed a rotating disk that eventually gave rise to our Sun and the planets, according to NASA.

Helium inherited from the solar nebula likely became trapped in Earth’s core as the planet formed, making the core a storehouse of noble gases. As helium-3 leaked from the core, it rose to the surface through the mantle in plumes of magma that eventually erupted on Baffin Island.

“During the eruption, the vast majority of the gases in the magma escaped into the atmosphere,” Horton said. “Only the olivine crystals that grew before the eruption captured the helium and kept it from deep within the Earth.”

New research supports the idea that helium-3 has been seeping out of the Earth’s interior for some time, but researchers aren’t exactly sure when this process began.

“The lava is about 60 million years old, and it probably took tens of millions of years for the mantle plume to rise,” Horton said. “So, the helium we measured in these rocks could have escaped from the core 100 million years ago or perhaps much earlier.”

He said that helium leakage from the ground does not affect our planet or have any negative effects. The noble gas does not react chemically with matter, so it will have no impact on humanity or the environment.

Next, the research team wants to check if the core is a storehouse of other light elements, which might explain why Earth’s outer core is less dense than expected.

“Is the core a major repository of elements like carbon and hydrogen, which are so important in terms of planetary habitability? If so, have fluxes of these elements from the core throughout (Earth’s) history influenced planetary evolution? “I’m excited to investigate,” Horton said. Bonds between helium and other light elements.” “Perhaps helium could be used to track other elements across the core-mantle boundary.”