Elemental analyses obsidian artifacts

Yegingil, Z. and T. Lunel (1990), Provenance studies of obsidian artifacts determined by using fission track ages and trace element analysis, Nucl. Tracks Rad. Meas. 17(3), 433. 

Bigazzi, G., Meloni, S., Oddone, M., and Radi, G. (1986). Provenance studies of obsidian artifacts trace elements analysis and data reduction. Journal of Radioanalytical and Nuclear Chemistry 98 353-363. 

Burger, R. L. Asaro, F. Trace Element Analysis of Obsidian Artifacts from the Andes New Perspectives on Pre-Hispanic Economic Interaction, Lawrence Berkeley Laboratory Report 6343 Berkeley, CA 1977 pp 1-88. 

Examples illustrating the use of PCA for identification and classification are given in Chapter 9, including classification of American Indian obsidian artifacts by trace element analysis, identification of fuel spills by gas chromatography, identification of recyclable plastics by Raman spectroscopy, and classification of bees by gas chromatography of wax samples. 

The use of trace element analysis to determine the provenance of archaeological materials has expanded rapidly in the last decade. It is now a well-established technique for the identification of obsidian source deposits (J), and is nearly as established for turquoise (2), steatite (3), and some ceramic materials (4). Native copper has received much less attention. Friedman et al. (5), Fields et al. (6), and Bowman et al. (7) used trace element analyses to determine the type of geological ore from which copper was extracted. However, only our efforts (8) and the work of Goad and Noakes (9) have focused on collecting and analyzing native copper from all potential deposits of a given region to provide a data base for statistical comparison with artifact trace element compositions. 

Spatially resolved trace analysis of early medieval archaeological iron finds Determination of minor and trace elements in obsidian rock samples and archaeological artifacts... 

In chapter 11, Tykot uses electron microprobe analysis to determine the major and minor elements in obsidian collected from sources throughout the Mediterranean region. Through statistical analysis, he is able to differentiate these sources and, thereby, is able to identify the sources of archaeological obsidian artifacts found in the region. Combining these data with contextual data, the relative frequency of particular obsidians in different sites can be used to infer that complex trade patterns existed in the Early Neolithic. 

In summary, we have determined LA-ICP-MS analysis to be an accurate and precise instrumental technique for chemical characterization of obsidian artifacts and source samples. We have developed two methods for normalization and standardization of obsidian data that while different, permit LA-ICP-MS data to be transformed to abundance data and that data derived by LA-ICP-MS conq>ares favorably to INAA data. The minimal sanq>le preparation time, the ability to select the suite of elements that will be analyzed, and the rapid analytic time make LA-ICP-MS, a minumUy invasive, cost-effective method for characterizing obsidian. 

In the Mediterranean Sea and Middle East area, for example, there are obsidian outflows only in Italy, in some islands in the Aegean Sea, and in Turkey. Artifacts made of obsidian, however, are widely distributed over much of this vast area. Chemical analysis of many of these artifacts has shown that most of the obsidian used to make them originated in one or another of the outflows mentioned, but also in far-distant places such as Armenia and Iran. Plotting on a graph the concentration of selected elements in samples from obsidian sources against that in samples from sites where it was used, enables the identification of the source of the samples (see Fig. 22). Moreover, this type of analysis also makes it possible to trace the routes through which obsidian (and most probably other goods) were traded in antiquity (Renfrew and Dixon 1976). 

Since the mid-1960s, a variety of analytical chemistry techniques have been used to characterize obsidian sources and artifacts for provenance research (4, 32-36). The most common of these methods include optical emission spectroscopy (OES), atomic absorption spectroscopy (AAS), particle-induced X-ray emission spectroscopy (PIXE), inductively coupled plasma-mass spectrometry (ICP-MS), laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectroscopy (XRF), and neutron activation analysis (NAA). When selecting a method of analysis for obsidian, one must consider accuracy, precision, cost, promptness of results, existence of comparative data, and availability. Most of the above-mentioned techniques are capable of determining a number of elements, but some of the methods are more labor-intensive, more destructive, and less precise than others. The two methods with the longest and most successful histoty of success for obsidian provenance research are XRF and NAA. 

Jampatilla, Peru, obsidian source, 536 Jen Tsung, coins, elemental composition, 233,237/-239/ Jiskairumoko, Peru, ochre artifacts instrumental neutron activation analysis, 480-505 mathematical and statistical data treatment, 492-501... 

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