Analysis by X-ray Fluorescence of Some American Obsidians

Analysis of minor or trace components of minerals has shown that the relative concentrations of these components often are uniquely characteristic of the source of the mineral, while those of the major components, e.g. silica or alumina, are not. In the case that there exist relatively few sources of the mineral but relatively many sites on which artifacts made from this mineral are found, such analysis can provide significant information on the mode of distribution and related attributes of the object. Obsidian is an example of such a mineral; a recent analytical study of European, Asian, and African obsidians (Cann and Renfrew 1964) has evolved information of the type mentioned. Recently developed instrumental methods of analysis are highly sensitive and rapid, and can often be carried out without damage to the specimen. It is the object of this and the following paper to describe the application of a technique of this kind aimed at relating obsidian objects found in Middle America to putative sources of the mineral, and to distinguish the sources from each other. This, we hope, will provide insight into the mutual contact of the various cultures with each other in prehistoric times.