Zambia Rift Shows Early Continental Breakup Signs

Scientists have uncovered evidence that a rift in central Zambia may represent an early stage of continental breakup, as gases bubbling from local hot springs carry distinctive isotopes from deep within Earth's mantle.

A study published in Frontiers in Earth Science analyzed samples from eight geothermal springs and wells in the Kafue Rift, part of a 2,500-kilometer-long Southwest African Rift System extending from Tanzania to Namibia. Researchers, led by Rūta Karolytė and Michael Daly of the University of Oxford, found elevated levels of helium-3 and carbon isotopes in gases inside the rift that match mantle signatures, typically found 40 to 190 kilometers below the surface. Springs outside the rift lacked these markers, ruling out atmospheric or crustal sources.

"This fluid connection is evidence that the fault boundary of the Kafue Rift is active," Daly said. The findings confirm mantle-derived fluids are rising through crustal faults, a hallmark of rifting where the lithosphere stretches and thins over geological time.

Previous observations had hinted at rifting in the region, including satellite imagery of fault scarps, high heat flow, low-level seismicity and geothermal...