Aerial View of the Kafue Rift’s Southern Boundary Fault Zone
Photo by Michael Daly
The African continent may be undergoing significant geological changes, as new evidence suggests that gas emissions from a series of hot springs in Zambia originate from deep within the Earth’s crust. This indicates the potential emergence of new tectonic plate boundaries.
Rift valleys, such as the prominent East African Rift stretching from the Red Sea to Mozambique, have showcased the gradual separation of continents over tens of millions of years. While it typically requires long periods for such tectonic activities to manifest, researchers are excited about the early signs of this process in Zambia’s Kafue Rift, according to Ruta Carolite from Oxford University.
The Kafue Rift forms part of an extensive 2,500-kilometer rift system stretching from Tanzania to Namibia and potentially reaching the Atlantic Ocean. Geologists hypothesize that this region is showcasing early indications of a new plate boundary due to its unique topography, gravity anomalies, elevated underground temperatures, and minimal seismic activity. Until recently, however, there was a lack of geochemical confirmation.
In their recent study, Karolytė and colleagues analyzed gas samples from five hot springs and three geothermal wells in central Zambia. Their findings showed that the isotopic ratios of helium and carbon in the gas closely resemble those found deep within the Earth’s crust. This suggests the presence of fluids originating from the mantle, as deep as 190 kilometers below the surface, indicating the awakening of tectonic rifting in the area.
“Our data confirm that this geological system is currently ‘active’ and in motion,” Carolite stated. “While the existence of an active rift valley doesn’t guarantee the formation of an ocean over the next 100 million years, the possibility remains.”
During the initial phases of continental rifting, gases trapped in rocks for millions of years are released. Notably, helium—a critical resource for high-tech and medical industries—has been detected in concentrations as high as 2.3% in the Kafue Rift’s fluids. This high concentration is drawing interest from industrial sectors.
“Identifying the ideal tectonic conditions to concentrate and release helium in a capture-friendly format is a challenging task,” Carolite explained.
Patrice Rey, a professor at the University of Sydney, concurs that while the region lacks active volcanoes or significant seismic events, there are numerous indicators of ongoing tectonic activity.
Recent geochemical insights from hot springs suggest that the Kafue Rift is transitioning towards becoming a continental rift, with primordial helium-3-rich mantle fluids ascending through its fractures. “It is plausible to foresee the Kafue Rift evolving into a plate boundary in the foreseeable future,” he remarks.
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Source: www.newscientist.com
