An Ancient Engineering Lab
In a series of caves at Pinnacle Point, on the southern coast of South Africa, archaeologists uncovered evidence of surprisingly advanced technology. Around 71,000 years ago, Middle Stone Age people were systematically selecting a specific type of rock, called silcrete, and carefully heating it in controlled fires. This process, known as heat treatment, changes the stone's internal structure, making it harder, tougher, and easier to flake with precision. The people at Pinnacle Point had discovered that by heating silcrete—likely by burying it under a fire at temperatures around 600 degrees Fahrenheit—they could produce superior raw material for their tools.
The primary products of this early pyrotechnology were small, sharp bladelets, also known as microliths. These tiny stone blades, often less than 10 millimeters wide, were components of more complex composite tools. They could be hafted onto wood or bone to create projectile weapons like arrows or throwing spears. This technology is a significant cognitive leap, requiring long chains of production and a deep understanding of material properties. Evidence for this heat treatment process appears as early as 164,000 years ago at Pinnacle Point, becoming a dominant technology at the site by about 72,000 years ago. This timeline places the innovation tens of thousands of years before similar techniques appeared elsewhere in the world.
A Coastal Refuge for Innovators
The caves at Pinnacle Point offered a workshop and were a refuge during a harsh ice age. Around 195,000 years ago, global climate conditions worsened, making much of inland Africa arid and uninhabitable. The southern coast of South Africa, however, remained a resource-rich environment. Excavations at sites like Cave 13B (PP13B) show that as early as 164,000 years ago, the inhabitants had a diverse diet that included systematic harvesting of marine life like shellfish.
This stable food supply, which also included plants and large game animals, likely supported the population that developed these advanced tool-making skills. The archaeological record at Pinnacle Point is remarkably continuous, showing occupation between 170,000 and 40,000 years ago. Within the layered sediments of the caves, scientists have found the heat-treated blades and some of the earliest evidence for symbolic behavior. This includes the collection and processing of red ochre, a pigment that was likely used for body painting or other forms of decoration. The combination of technological innovation, resource exploitation, and symbolic thought found at Pinnacle Point shows the lives of early Homo sapiens.