A newly discovered helium field in the geothermally active East African Rift Valley may contain more helium than the U.S. Federal Helium Reserve near Amarillo, Texas, which holds about 30 percent of the world’s helium supply.
Independent experts have calculated a probable resource of 54 billion cubic feet [1.5 billion cubic meters] in just one part of the rift valley.
The Federal Helium Reserve currently holds just 24.2 billion cubic feet, and the total known reserves in the U.S. contain about 153 billion cubic feet (4.3 billion cubic m), Ballentine said, while global consumption of helium is about 8 billion cubic feet (0.23 billion cubic m) per year.
The newly discovered gas field in Tanzania holds enough helium “to fill over 1.2 million medical MRI scanners,” he said: “This is a game changer for the future security of society’s helium needs, and similar finds in the future may not be far away.”
One of the project leaders, geologist Jon Gluyas of Durham University, told Live Science that although the Tanzania gas field is large, it’s only a small part of what the entire Rift Valley area may contain. “So it could be substantially larger,” Gluyas said. “We will still have a lot of data to collect to be really confident, but yes — this is a globally significant discovery.”
A new approach
Gluyas said the discovery hinged on a new understanding of the very complex and ancient nuclear, chemical and geological mechanisms that create helium in the Earth’s crust and transport it into pockets that can be tapped by drilling.
“Almost more significant than the volume of helium found is that it was found on purpose,” he said. “Every other discovery of helium to date has been found by accident.”
Helium accumulates inside rock in the Earth’s crust over billions of years, from the radioactive decay of the elements uranium and thorium. But the gas remains trapped in the rock until it is freed by very intense volcanic heat, such as that found in geothermally active regions such as the East African Rift Valley, Gluyas said.
By studying that process and the geological mechanisms that cause freed helium gas to accumulate in pockets, the researchers were able to identify potential drilling sites, he added.
Gluyas said the team took the same protocols and “applied the same sort of thinking you would for finding oil” to finding helium.
The fusion of hydrogen atoms produces large amounts of helium in the nuclear processes that power the sun. But here on Earth, helium is hard to find and hard to keep hold of, Gluyas said. Helium atoms are so small that the gas leaks out of almost every sort of container, and once helium escapes into the atmosphere, it’s gone for good, he explained.
“In a bizarre sort of way, it is the ultimate nonrenewable element, and at the moment, it is not replaceable for many applications, certainly for medical systems such as MRI scanners,” Gluyas said
Researchers knew that volcanoes (including Yellowstone) often had helium sources nearby. Future research will likely look at narrowing down the areas where governments and companies can successfully prospect for helium.
“We show that volcanoes in the Rift play an important role in the formation of viable helium reserves. Volcanic activity likely provides the heat necessary to release the helium accumulated in ancient crustal rocks. However, if gas traps are located too close to a given volcano, they run the risk of helium being heavily diluted by volcanic gases such as carbon dioxide, just as we see in thermal springs from the region. We are now working to identify the ‘goldilocks-zone’ between the ancient crust and the modern volcanoes where the balance between helium release and volcanic dilution is ‘just right’,” said Diveena Danabalan, lead author of the research.
SOURCES – Live Science, Popular Science