Overview
- An Oxford-led paper published Tuesday in Frontiers in Earth Science reports mantle-derived helium and carbon signatures in gases from hot springs along Zambia’s Kafue Rift.
- Scientists sampled eight geothermal sites, finding mantle-like helium ratios at six locations inside the rift but not at two control sites outside it.
- Helium isotope ratios are a mantle tracer because the mantle holds more primordial helium-3 than the crust, which mostly produces helium-4 through radioactive decay.
- The data indicate faults there cut through the crust into the mantle and that rifting is active, though the authors caution this is an early signal and not proof of a plate boundary.
- The Kafue Rift sits within a 2,500-kilometre Southwest African rift zone that could evolve over millions of years, and the findings are already drawing interest in local geothermal energy and recoverable helium.