Neutron activation analyses obsidian sources

Williams-Thorpe, O., S. E. Warren, and J. G. Nandis (1997), Characterization of obsidian sources and artefacts from central and eastern Europe, using instrumental neutron activation analysis, in Korek, J. (ed.), Proc. Int. Conf. Lithic Raw Material Characterization, Budapest and Siimeg, 1996, Budapest. 

It was not until the application of neutron activation analysis (NAA) that the problem of overlapping sources could be tackled. NAA is a highly sensitive and essentially non-destructive technique, although samples have to be taken which remain radioactive for some time after analysis. The use of NAA in characterizing obsidian was first demonstrated in the early 1970s (Aspinall... 

In most obsidian provenance studies, the ability to employ compositional differences to discriminate between sources depends, to a certain extent, on the number of elements measured. Because instrumental neutron activation analysis (INAA) is capable of measuring 25-30 elements in obsidian with excellent precision, numerous combinations of trace and major elements are available for comparing differences between sources. The main requirements for success are that all sources have been located and analyzed, and that the internal variation measured within the sources be smaller than the compositional differences measured between the sources (23). 

Use of obsidian in South America has been documented from about 13,000 years B.P. through the beginning of the Spanish Conquest. Several of the most archaeologically important sources of obsidian in South America are located in the Andes. mountain region of southern Peru. Due to the difficult terrain and volatile political environment, the locations for many of these sources were unknown to archaeologists until quite recently. Neutron activation analysis and X-ray fluorescence have been used to measure the compositional patterns for individual sources. The comprehensive source database established by this work enables definitive and cost-effective assignments of provenance to obsidian artifacts from archaeological sites in Peru and northern Bolivia. 

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. 

Mesopotamian glazed ceramics, 430-433,435/, 437-440 obsidian sourcing, 278,279-281 See also Neutron activation analysis Intermountain Region, North America, historic pottery, 447-459 Iran, Neolithic, bitumen traces in ceramic vessels, 137-151 Iran, Neolithic sites Ali Kosh, 138, 139/... 

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... 

---