Thursday, February 23, 2012

Ceramic Sourcing and Analysis: Woodlands

Carr, Christopher and Jean-Christophe Komorowski
1995 Identifying the Mineralogy of Rock Temper in Ceramics using X-Radiography American Antiquity 60(4):723-749

This article provides a thorough description and explanation of the method for ceramic analysis called x-radiography, while also providing an example from several middle Ohio Woodlands sites. In particular, this article sought to analyze the mineralogy of the rock temper of the ceramics, which is a more technical way of saying that they were sourcing the ceramics. This method was taken from the medical field and is more desirable, according to the authors, than thin-section analysis as it is not as destructive to the ceramic sherds.
Early in the article, the authors compare their method, x-radiography, with other methods used to look at the mineralogy of ceramics, including looking at them under hand lens and microscopes of varying strengths, going as far as electron microscopes. X-radiography is the ideal choice for several reasons. First, x-radiography allows for more precise analysis than that of hand lens analysis (though not as precise as using binocular microscopes). Secondly, it is more precise in examining particle size than petrography (which I looked at in the plains a few weeks ago) is. X-radiography is a cost-effective method of analysis for large yields of sherds, comparable to the costs of binocular microscopy, but cheaper than petrography. Lastly and most importantly, x-radiography is completely nondestructive, while nearly every other method of analysis that yields the same results requires at least some minor destruction.
In testing x-radiography, they did blind tests of sherds found in late Middle Woodland sites in Ohio, which had been populated by the Hopewell, stating that "this information bears on the manner in which Hopewellian households were integrated socioeconomically, and on the nature of local exchange systems." (739) What they find is that there is a wide variety of minerals in the sherds, including quartz, different types of feldspar, and many other minerals.
The site that they used was a small farming village that may have been as small as one or two households. The wide variety of minerals evident in the ceramic sherds demonstrates that the Hopewell did indeed have extensive trade. Further, the authors make mention of evidence from the site of a dispersed community model, but they did not go into too much depth about that.

Stoltman, James B.
1989 A Quantitative Approach to the Petrographic Analysis of Ceramic Thin Sections American Antiquity 54(1):147-160
    This article concerns another method of analysis, related to petrographic analysis, which is ceramic paste comparison. The article starts out by discussing petrographic analysis and what the author calls its “underutilization in North American archaeology” (147) He says that in regards to North American archaeology, petrographic analysis is often treated as only a method of decorative classification when it actually has several other applications. It can also be used to determine sourcing as well as determining typology.
    Stoltman mentions that there are two approaches to quantitative analysis: visual comparison and point counting. Visual comparison is done by comparing samples to already counted examples to determine the temper and other data. Stoltman acknowledges that this method does have success, but it is not as accurate as point counting is. Point counting is done by superimposing a grid and then analyzing each section with a microscope (148). Stoltman dedicates an entire section to pointing out errors in point-count analysis before moving on to discussing his ideas on methodology.
    In order to better illustrate his points, Stoltman applies his proposed techniques to various sites through the northwest of the Woodlands. What he found was that while some previously made classifications held up to his new ceramic paste analysis; in other sites, sherds were misclassified due to improper analysis. Stoltman reasons that this is because similar designs styles can complicate attempts to determine technological differences.
    In his conclusion, Stoltman reiterates his belief that petrographic analysis is an underutilized method in North American archaeology. In his opinion, petrographic analysis succeeds in situations where either visual comparison or point-count analysis fails. What he found was that certain typologies that were thought to be established were actually different. This demonstrates that the best choice is to use more than one method of analysis to get the most complete picture of the ceramics of a region or site.

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