Earth core leaking: Scientists have discovered surprising amounts of rare helium gas, known as helium-3, in volcanic rocks on Canada’s Baffin Island, supporting theories that the noble gas spewed from the Earth’s core and has been there for thousands of years. The research group also discovered helium 4 in the rocks.
Although helium-4 is common on Earth, helium-3 is much more easily found elsewhere in the universe, so scientists were surprised to discover that Baffin Island’s rocks turned up higher amounts of the element than previously reported. The results were described in a recent study published in the journal Nature.
“At the most fundamental level, there is very little 3He (helium 3) in the universe compared to 4He (helium 4),” said Forey, the study’s lead author and an associate scientist in the Department of Geology and Geophysics at Woods Hole Oceanographic Institution. , Forrest Horton said. , in e-mail. “3 It is rare on Earth because it is not produced or added in large quantities here and is lost to space,” Horton added. “When the rocky parts of the Earth are like hot water on a stove, when they are stirred and convected, matter rises, cools and sinks. During the cooling phase, helium is lost to the atmosphere and then to space. “
The discovery of elements emanating from the Earth’s core can help scientists gain insight into how our planet formed and evolved over time, and the new findings provide evidence that supports existing hypotheses about how our planet formed.
Treasury of “Scientific Treasures”.
Baffin Island, located in Nunavut, is Canada’s largest island. It is also the fifth largest island in the world.
Solway Lass-Evans, doing his PhD under the supervision of University of Edinburgh scientist Finley Stewart, first discovered a high ratio of helium 3 to helium 4 in the volcanic rocks of Baffin Island. Their findings were published in Nature in 2003.
A planet’s composition reflects the elements from which it was formed, and previous studies have detected small amounts of helium-3 escaping from Earth’s core, supporting the popular theory that our planet originated in the solar nebula, a cloud of gas and dust. which could be It collapsed due to a shock wave from a nearby supernova containing this element. In 2018, Horton and his colleagues conducted research on Baffin Island, where they studied lava that erupted millions of years ago when Greenland and North America split apart and gave way to new seafloor. They wanted to study rocks that could hold insights about the materials in Earth’s core and mantle (the mostly solid layer of Earth’s interior that lies below the surface). Scientists flew by helicopter to reach the island’s remote, otherworldly landscape, where lava flows form towering cliffs, giant icebergs float and polar bears roam the shores. Horton said local organizations, including the Chiquiktani Inuit Association and the Nunavut Research Institute, provide researchers with access to the bears, counseling and protection. “This area of Baffin Island is of particular importance, both as a sacred site for the local community and as a scientific window into the depths of the earth,” he said.
The arctic rocks studied by Horton and his team showed much higher measurements of helium-3 and helium-4 than previous studies had reported, and the measurements varied between the samples collected. “Many lavas are filled with pale green olivine (also known as the gemstone peridot), so chipping a fresh shard with a rock hammer is as exciting as a child opening a geode: each rock is a treasure waiting to be discovered,” Horton said. . . “What a precious gem of science they turned out to be!”
Horton said that for every million helium-4 atoms there is only one helium-3 atom. The team measured about 10 million helium-3 atoms per gram of olivine crystal.
“Our high 3He/4He measurements suggest that gas, possibly inherited from the solar nebula during the formation of the solar system, is better preserved on Earth than previously thought,” he said.
Tracing Earth’s History
But how does helium-3 get into rocks in the first place?
The answer lies in the Big Bang, which also released massive amounts of hydrogen and helium when the universe was formed. Over time, these elements were incorporated into the formation of galaxies.
Scientists believe that our solar system formed in the solar nebula 4.5 billion years ago. According to NASA, when the dust cloud collapsed in a supernova, the resulting material formed a rotating disk that eventually formed our sun and planets.
When the Earth formed, helium inherited from the solar nebula may have been locked in the core, making the core a reservoir of noble gases. As helium-3 seeps out of the Earth’s core, it rises in plumes of magma through the mantle to the surface, eventually erupting on Baffin Island.
“During an eruption, most magma gases escape into the atmosphere,” Horton said. “Only olivine crystals that grew before the eruption could trap and store helium deep in the Earth.”
The new study supports the idea that helium-3 is leaking from Earth’s core and has been leaking for some time, but scientists aren’t exactly sure when the process started.
“The lava is about 60 million years old, and it can take tens of thousands of years for the mantle to rise,” Horton said. “So the helium we measure in these rocks may have escaped the core 100 million years ago or earlier.”
He said that the leakage of helium from the Earth’s core will not affect our planet and will not cause any negative consequences. Inert gases do not react chemically with substances, so they have no effect on people or the environment. Next, the team wants to investigate whether Earth’s core is a storehouse of other light elements, which could explain why Earth’s outer core is less dense than expected.
“Is the core the main reservoir of elements like carbon and hydrogen that are important for the habitability of the planet? If so, did the flow of these elements from the core over history affect the evolution of the planet? I’m excited to explore the connection between helium and other elements of light,” Horton said. “Perhaps helium could be used to trace other elements that cross the core-mantle boundary.”