An Academic Paper Review
In my continuing review of the recent literature concerning use-wear analysis of stone tools, I encountered an excellent paper by Werner (2018). In this paper, Werner reports on the impact of post-depositional damage in accurately identifying use-wear traces on stone tools.
Werner summarizes very well the current status of use-wear research:
First, the formation of use-wear is not yet completely understood.
Second, there has arguably been an overemphasis on the study of flint/chert assemblages leaving use-wear on non-flint tool-stones underexamined.
Third, many aspects of the burial environment are known to be capable of interfering with the interpretability of use-traces.
Lastly, the majority of use-wear analyses remain inherently subjective, difficult to reproduce and independently verify.
To address 3 and 4, Werner conducts a post-depositional experiment using a laser confocal microscope. This microscope is capable of capturing measurements to quantify changes in use-wear traces after post-depositional impacts.
Werner used 10 dacite flakes, gray volcanic stone, in a sawing motion on wood covered in bark, dry antler, dry hide, and dry grass stems and leaves for 40 minutes each. These used flakes were than placed in a sieve with sand and shaken for 30, 60, and 90 minutes.
Werner found that post-depositional damage in this experiment was correlated with the amount of shaking time. By 90 minutes, post-depositional damage obliterated most of the original use-wear traces.
Antler and wood use-wear traces were the most impacted from post-depositional damage.
Polish from use on plant material is distinctive and can more easily be identified even with post-depositional impacts.
Experiments such as these are important, as Werner states:
The likely reality is that lightly and moderately damaged assemblages are analyzed routinely, either knowingly or unknowingly.