An assessment of whether saturated sediment ablation on stationary bone can mimic bone tool use-wear from Earlier Stone Age contexts

Several taphonomic processes can alter the surface of archaeological bone in a manner that may cause them to superficially resemble bone tools used as digging implements. Under close examination, however, the resultant microwear is usually quite distinct. While many experiments have been done to document the effects of fluvial processes on bone surface alteration, there are many mass soil movement process whose microwear effects have not yet been properly investigated and which could conceivably produce microwear similar to digging implements. One example, which pertains to the Cradle of Humankind landscape, is soil creep. We present the results of an experiment that assesses the resultant microwear on stationary bones occasioned by artificially accelerated soil creep processes. We show that the passage of saturated sediments over stationary bones produces rounding and pitting, and does not resemble microwear occasioned either by fluvial transport or experimental digging in sediments. Although there is room to test additional variables, we conclude that the purported bone tools from the Cradle of Humankind sites were not affected by soil creep processes, at least not to the extent that they caused surface alterations.