The study of gas emission rates, chemistry and isotopic analyses show that the rate of helium-4 emission from the crust at Yellowstone is orders of magnitude greater than any conceivable rate of generation within the crust; this implies that helium has accumulated for hundreds of millions of years in deeper Archaean cratonic rocks, only to be liberated over the past two million years by crustal metamorphism induced by the Yellowstone hotspot.
- J. B. Lowenstern
- W. C. Evans
- A. G. Hunt
