TRAMPLED FLAKES
Several researchers have sought to determine whether natural fractures arising from “trampling” can mimic intentional flaking or retouch. In this context, “trampling” means someone (human or potentially another animal) walking over a flake, whether isolated or in a heap of material. The results are interesting and have important implications for artifact identification since the short answer to the question is “yes”.
Human Trampling as an Agent of Lithic Artifact Edge Modification
McBrearty et al published “Tools Underfoot: Human Trampling as an Agent of Lithic Artifact Edge Modification” in American Antiquity vol. 63 no. 1 in 1998 which you can download here:
http://www.anth.uconn.edu/faculty/mc...0Underfoot.pdf
The main question she and her co-workers addressed was: “can trampling produce edge damage that mimics deliberate retouch?” Although the question was posed in the context of European Palaeolithic Mousterian (Neanderthal) denticulate knife/scrapers the conclusions are equally valid elsewhere.
The authors’ main conclusions were that:
1. Artifact lithic raw material, artefact density and substrate (ie the nature of the ground surface on which the artefacts were laying) all contributed to edge modification to some degree but substrate had the major effect - ie harder surfaces.
2. Trampling does tranform flakes into “pseudo-tools” to the extent that they can then be “classified” as formal tools using standard typology.
Experimental Production of Bending and Radial Flake Fractures and implications for lithic technologies
Thomas A. Jennings published “Experimental Production of Bending and Radial Flake Fractures and implications for lithic technologies” in the Journal of Archaeological Science in 2011, which you can download here:
http://www.centerfirstamericans.com/...s-2011-JAS.pdf
Jennings seeks to answer the question of whether “bending” and radially broken flakes in Paleoindian lithic assemblages can be reliably attributed to intentional tool production as opposed to scavenged flakes from reduction processes. More importantly, he goes on to try and answer the question of whether either of those processes can be distinguished from accidental breakage arising from “trampling”… ie people (or potentially other animals) walking over flakes of stone.
He compared three sets of flakes which he had produced himself: (a) intentionally fractured by percussion; (b) incidentally fractured, but produced from intentional bifacial reduction of a core; (c) broken by trampling.
The trampled flakes were produced as follows. Twenty Edwards chert flakes were individually placed on a dry, hardened, silty-clay soil surface and he then simply stepped on each of them. If they broke, he gathered up the fragments for analysis. If they didn’t, he stacked them in piles of three and stepped on them again to simulate “flake-on-flake” trampling as might happen in a pile of lithic debris. Anything with breaks larger than 1cm from the second attempt were also gathered up for analysis.
His main conclusions were:
1. Intentional fracturing can be distinguished from incidental fracturing in reduction flakes by the presence of point of impact markers, break angles close to 90 degrees and high percentages of bend and radial breaks.
2. Fractures from intentional flaking can be distinguished from trampled flakes by their high percentages of radial breaks.
3. It may not be possible to identify intentional fractures in bifacial reduction flakes which have been severely affected by flake-on-flake trampling.
Several researchers have sought to determine whether natural fractures arising from “trampling” can mimic intentional flaking or retouch. In this context, “trampling” means someone (human or potentially another animal) walking over a flake, whether isolated or in a heap of material. The results are interesting and have important implications for artifact identification since the short answer to the question is “yes”.
Human Trampling as an Agent of Lithic Artifact Edge Modification
McBrearty et al published “Tools Underfoot: Human Trampling as an Agent of Lithic Artifact Edge Modification” in American Antiquity vol. 63 no. 1 in 1998 which you can download here:
http://www.anth.uconn.edu/faculty/mc...0Underfoot.pdf
The main question she and her co-workers addressed was: “can trampling produce edge damage that mimics deliberate retouch?” Although the question was posed in the context of European Palaeolithic Mousterian (Neanderthal) denticulate knife/scrapers the conclusions are equally valid elsewhere.
The authors’ main conclusions were that:
1. Artifact lithic raw material, artefact density and substrate (ie the nature of the ground surface on which the artefacts were laying) all contributed to edge modification to some degree but substrate had the major effect - ie harder surfaces.
2. Trampling does tranform flakes into “pseudo-tools” to the extent that they can then be “classified” as formal tools using standard typology.
Experimental Production of Bending and Radial Flake Fractures and implications for lithic technologies
Thomas A. Jennings published “Experimental Production of Bending and Radial Flake Fractures and implications for lithic technologies” in the Journal of Archaeological Science in 2011, which you can download here:
http://www.centerfirstamericans.com/...s-2011-JAS.pdf
Jennings seeks to answer the question of whether “bending” and radially broken flakes in Paleoindian lithic assemblages can be reliably attributed to intentional tool production as opposed to scavenged flakes from reduction processes. More importantly, he goes on to try and answer the question of whether either of those processes can be distinguished from accidental breakage arising from “trampling”… ie people (or potentially other animals) walking over flakes of stone.
He compared three sets of flakes which he had produced himself: (a) intentionally fractured by percussion; (b) incidentally fractured, but produced from intentional bifacial reduction of a core; (c) broken by trampling.
The trampled flakes were produced as follows. Twenty Edwards chert flakes were individually placed on a dry, hardened, silty-clay soil surface and he then simply stepped on each of them. If they broke, he gathered up the fragments for analysis. If they didn’t, he stacked them in piles of three and stepped on them again to simulate “flake-on-flake” trampling as might happen in a pile of lithic debris. Anything with breaks larger than 1cm from the second attempt were also gathered up for analysis.
His main conclusions were:
1. Intentional fracturing can be distinguished from incidental fracturing in reduction flakes by the presence of point of impact markers, break angles close to 90 degrees and high percentages of bend and radial breaks.
2. Fractures from intentional flaking can be distinguished from trampled flakes by their high percentages of radial breaks.
3. It may not be possible to identify intentional fractures in bifacial reduction flakes which have been severely affected by flake-on-flake trampling.
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