Kevin Trujillo
Jeffery Frost
Anthropology 2090
December 3, 2014
The Ceren Site: The Use of the Obsidian Blades
During the case study and excavation of the ceren site in El Salvador that began in 1978,
Payson Sheets and his team uncovered a collection of artifacts within and around the eighteen total structures found thus far. Among these artifacts were a collection of prismatic obsidian blades and scrapers that Payson believes were used for activities such as: processing deer hide, smoothing wooden artifacts, or eve sharpening digging sticks. Payson was able to conclude the reasons behind the storing and disposal of the obsidian blades but never really provided any conclusions for what the blades were used on. However, with the the methods proposed by
Sergei Semenov (1964) and enhanced by Lawrence Keeley of the University of Illinois Chicago
(1980), I believe that we can properly conclude what the true use of the blades were and further enrich the history of the Ceren Site.
Semenov and Keeley worked on a technique known as micro wear analysis; which involves the use of microscopes to study the edges of stone tools. When a tool is used against another object, it leave a series of scratches or grooves which vary in size and depth according to the specific material it was used against. With that known, Lawrence Keeley preformed blind tests to compare the characteristics of the wear of stone stones when used against specific materials. This provided the knowledge to identify whether a tool was used against materials

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such as dry hide, meat, wood, and plant fibers. Furthermore it allowed archaeologist the opportunity to see if the stone tools were used to make other tools from other materials; tools made of bone, antler, or wood.
Semenov and Keeley also provided valuable information on how soft worked materials and hard worked material behaved when used on a material. For example, “soft worked materials offer a broader contact area between the tool and the contact material, resulting in bending fractures along a tool edge while hard worked materials offer a narrower contact area between the tool and the contact material, resulting in cone-initiated removals and edge crushing” (Lawrence, 1979; Price). With this is mind, we can apply these known facts the the obsidian tools found at Joya de Ceren. When under a microscope, if a tool had a heavily worn and rounded distal edge, it was most likely used as a scraper on dry animal hide. Furthermore, if a tool had a jagged, rough distal edge, it may have been used to drill or scrape wood or used to haft other materials.
Due to the fact that the village was buried under 5-7 meters of volcanic ash, the tools found at the site were not subject to certain weathering and deterioration of the climate in El
Salvador. This provides archaeologist better test samples with more definite scratches and grooves. Once archaeologist determine the use of an artifact, they could then correlate it to the its finding place which could help answers questions of origin, economics, and practices within a particular community. For example, if they examined the obsidian tools and found that none of them had signs of being used to cut other materials (a rough biface), then the question arises of if

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the community was trading with other nearby communities and if so, how and what was they exchanging. In conclusion, the use of micro wear analysis, a technique pioneered by Semenov and
Keeley, archaeologists are able to determine the uses of specific lithic tools based off the scratches, grooves, and overall wear of the material’s edges. The use of this technique can aid archaeologists answer questions that deal with the specific use of a lithic material, how it was used, and the origin of the material (whether or not it was reused). Although this method is timeconsuming, micro wear analysis studies offer one of the only way to reliably understand the use of lithic materials.

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