Deep beneath South Africa’s famous gold fields, scientists have uncovered evidence of a rare and precious gas that has been quietly building up for nearly three billion years. Helium, a non-renewable element critical for medical imaging and scientific research, is trapped inside some of the oldest rocks on Earth in the Witwatersrand Basin.
The discovery comes from research led by Fin Stuart of the University of Glasgow’s Centre for Isotope Sciences. His team has been studying how helium forms deep underground, how it moves through rock, and how it can survive intact for immense geological periods. Their findings suggest that ancient rocks beneath the basin have acted like a natural vault, holding helium since long before complex life appeared on Earth.
At the centre of this research is the Virginia gas project in South Africa, where natural gas extracted from deep underground contains unusually high concentrations of helium, sometimes reaching up to 12 per cent. Estimates suggest the field may contain more than 400 billion cubic feet of helium, making it one of the most significant known reserves in the world.
Scientists believe the helium began forming billions of years ago as uranium and thorium in gold-bearing rock layers slowly decayed, releasing helium atoms over time. These rocks, known as the Witwatersrand Supergroup, are between 2.8 and 3 billion years old. Above them, layers of sediment deposited around 270 million years ago sealed the gas underground, preventing it from escaping.
Additional helium likely comes from even deeper granite formations beneath the basin. Fractures in this ancient crystalline rock allow helium to migrate upward, where it becomes trapped along with methane in underground reservoirs.
Helium is essential for cooling the powerful magnets used in MRI scanners, which hospitals around the world rely on for medical diagnosis. It is also used in semiconductor manufacturing, space research, and advanced physics experiments. Because helium is produced extremely slowly and cannot be replaced once released into the atmosphere, global shortages have become a growing concern.
The Virginia field offers rare long-term security. A helium reserve capable of supporting decades of production could ease pressure on global supply chains and help stabilise access for hospitals and research institutions.
The study also reveals a complex underground system where geology, microbes, and groundwater interact. Researchers have found that methane in the region is produced by microbes living nearly three kilometres below the surface. Groundwater moving through deep faults collects methane and helium, carrying them upward until gas bubbles form and become trapped in underground structures like the Virginia field.
To better understand this process, the research team will study microscopic rock samples, measure helium trapped inside mineral grains, and analyse gas from production wells. By combining these datasets, they aim to build a detailed model of how helium is generated, stored, and released over geological time.
The project has broader implications beyond helium exploration. Because helium is chemically inert and easy to detect, it can also be used to monitor whether carbon dioxide injected underground for climate mitigation remains securely stored or leaks back to the surface.
The University of Glasgow is now recruiting a doctoral researcher to continue this work, offering hands-on training in field sampling, laboratory analysis, and collaboration with industry partners. The goal is not just to understand one gas field, but to develop tools that could help identify similar helium-rich regions in other ancient parts of the world.
The story of helium beneath the Witwatersrand Basin links radioactive decay in Earth’s earliest crust, microbial life deep underground, and modern human dependence on advanced technology. As scientists refine their models, the lessons learned from these ancient rocks may shape how the world secures one of its most irreplaceable resources for the future.