Archaeologists working in the Eastern Cape of South Africa have applied a new isotopic dating technique to solve the long-standing mystery of the region's megalithic stone circles. By measuring the accumulation of Magnesium-26 in the quartz crystals of the foundation stones, researchers have dated the construction of these sites to 4200 BCE. This new date is over a thousand years earlier than previously thought, placing these structures among the earliest complex stone architectures in Southern Africa.
The research, published in the African Archaeological Review, suggests that Neolithic pastoralists in the region had developed communal labor systems and sophisticated geometrical planning much earlier than current historical models allow. The Magnesium-26 methodology is particularly effective for dating surface-exposed rocks that were moved by human activity, providing a direct link to the builders. This discovery challenges the conventional view of early African societies and highlights the continent's early history of monumental engineering.