The first industrial chemists
In a series of sea-facing caves at Pinnacle Point, archaeologists found evidence of pyrotechnology dating back 164,000 years. Middle Stone Age people living here systematically engineered stone tools using carefully controlled fires. This discovery pushed back the timeline for this complex technology by tens of thousands of years. Before the finds at Pinnacle Point, the earliest known examples of heat treatment were from Europe, dated to about 25,000 years ago.
The raw material at the heart of this process is a type of rock called silcrete. In its natural state, the local silcrete is a poor-quality material for making tools because it is difficult to shape with precision. The early modern humans at Pinnacle Point discovered that by heating it, they could transform its properties. The heat treatment made the silcrete harder and more brittle, allowing for much finer and more predictable flaking. This process allowed them to create small, sharp blades known as microliths, likely for use as projectile points.
The process itself was a remarkable feat of early engineering. Archaeologists, led by Kyle Brown of the University of Cape Town, determined through experimentation that the silcrete had to be heated slowly and evenly. The method involved burying the stone in sand and then building a fire on top, maintaining a temperature between 300 and 400 degrees Celsius. This controlled heating altered the stone's internal structure, making it an outstanding raw material for advanced tools.
Evidence of advanced thought
The use of heat treatment at Pinnacle Point demonstrates advanced cognitive abilities. This was not a single-step action but a long-chain technological process that required abstract thought, planning, and patience. These early humans understood that investing time and energy in a complex heating process would yield a superior material for toolmaking later on. This understanding of cause and effect, and the ability to follow a precise recipe to transform a material, shows complex cognition.
The ability to teach and transfer this multi-step knowledge across generations was also fundamental. It likely required language to explain the nuanced process of selecting the right stones, burying them correctly, managing the fire's temperature, and allowing for proper cooling. The findings at Pinnacle Point show of evidence showing that "modern" human behavior appeared far earlier than previously thought, and that it originated in Africa. The site also contains some of the earliest evidence for the systematic harvesting of marine resources and the use of pigments like ochre, all dating back to approximately 164,000 years ago.