SOME APPLICATIONS OF LA-TOF-ICP-MS IN ARCHAEOLOGICAL PROVENANCE STUDIES

Coupling a laser ablation (LA) system to a time-of-flight (TOF) ICP-MS creates a powerful microprobe that is capable of determining most elements of the periodic table with laser ablation times of one second or less. This means, for example, that individual temper inclusions in archaeological pottery can be reliably characterized separately from the surrounding matrix, so that the contribution of the temper to the ceramic bulk composition can be determined. In addition, because a TOF characterizes all ions present in a sample stream at a given time, isotope ratios can be determined with good precision via LA-TOF.

At the IIRMES (Institute for Integrated Research in Materials, Environments, and Society) lab at Cal State Long Beach, we have been using a GBC Optimass 8000 TOF coupled to a New Wave UP213 laser in archaeological provenance research for the past 3 years. Applications have included characterization of mica schist particles in micaceous pottery from the Southwest, characterization of lead isotopes in glass beads, lead shot, and ceramic glazes, and demonstration of the feasibility of characterizing obsidian micro-debitage. This paper reports the results of these applications and from some more traditional archaeological provenance applications. Methodological issues that affect the reliability and accuracy of data obtained by LA-TOF are discussed as well.