Humans are remarkable for our ability to innovate new tools with which to modify our environment and to create new ways of conveying and storing information with material symbols. My research focuses on how ochre, a family of mineral pigments made from iron oxides and hydroxides (rust), was used by the earliest Homo sapiens for both practical and symbolic purposes.
Archaeologists have hypothesized that ochre was used for decorating one’s body, processing animal hides, producing rock art, and for making adhesive to mount stone tools on wood and bone shafts. A recent study of stone tools from the South African site of Sibudu has confirmed that ochre was used to make composite tools in this way. My current project investigates how effective three different ochreous minerals are in making an adhesive used to attach stone arrowheads to a wooden shaft.
Projectile weapons like arrows were a major technological advance and allowed humans to hunt dangerous prey from a distance and to target small, fast moving animals. Since ochre-containing adhesive may have been crucial to making effective arrows, this could partially explain why over 200,000 years ago humans were collecting ochre and transporting it to their habitation sites. Using an African tree resin as a base, I will make three adhesive recipes with the different types of ochre and test the resulting arrows as hunting weapons by firing them into a goat carcass and assessing the hardness of the adhesive, wound depth on the carcass, and the ability to reuse each arrow.