http://www.livescience.com/55204-huge-cache-of-ancient-helium-discovered.html
By one estimate, the 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.
How much helium?
The Tanzania discovery was made by researchers from the University of Oxford and Durham University, both in the U.K., working with Helium One, a helium exploration company headquartered in Norway.
"We sampled helium gas (and nitrogen) just bubbling out of the ground in the Tanzanian East African Rift valley," Chris Ballentine, a geochemist in the Department of EarthSciences at Oxford University, said in a statement. "By combining our understanding of helium geochemistry with seismic images of gas-trapping structures, 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."