The gold in this region does not come from magmatic processes, but from ancient rivers.
Since the late 19th century, the Witwatersrand basin has established itself as a global benchmark in mining, contributing approximately 40% of the gold mined throughout human history. This discovery, which is not recent, has significant historical value, but its magnitude has reawakened the interest of the scientific community.
In the Witwatersrand formation, located in South Africa, recent research has confirmed that the mountains, which rise more than 1,900 metres above sea level, harbour the remains of an ancient river system that concentrated thousands of tonnes of gold more than 2.7 billion years ago.
However, new geological models are providing a deeper understanding of how and why this metal accumulated in such abundance at that altitude.
The area that harbours gold at an altitude of over 1,900 metres
Geological history hides many mysteries. The gold of the Witwatersrand was not formed through magmatic processes, but was the result of primitive rivers that, during the Archaic period, transported metallic particles to the beds of ancient valleys. Over millions of years, sedimentation, pressure and tectonic activity consolidated these deposits into conglomerates that are now found at high altitude.
Reports from international entities such as the USGS and the Council for Geoscience of South Africa corroborate that, adding up what has already been mined and what remains, the region is home to reserves that could exceed 30,000 tonnes. For this reason, it is considered the most significant natural mine ever documented.
The evolution of gold in Witwatersrand
The mining boom was one of the fundamental elements that transformed the landscape and gave rise to Johannesburg, now recognised as the economic capital of South Africa. The deep mines, which exceed three kilometres underground, marked the advancement of modern mining engineering. Despite environmental and social challenges, the region remains a symbol of large-scale mining.
The gold of the Witwatersrand not only contributed to the economy; it also fostered the creation of scientific institutions, universities and safety regulations that were later adopted by other mining countries. It is, in essence, the nucleus upon which an entire nation was built.
Secrets buried in the mountains
Although the large veins have been mined for over a century, geologists maintain that there are still unexplored areas at the edges of the basin. New seismic exploration techniques and deep sampling seek to identify hidden concentrations of residual gold trapped in older layers.
Scientific expectations focus on gaining a deeper understanding of the processes that gave rise to these unique deposits and how they could be replicated in other regions of the planet. Even today, Witwatersrand remains a window into the distant past of the Earth and one of the keys to understanding the formation of mineral resources on our planet.