Application of prompt gamma activation analysis to provenance study of the Korean obsidian artefacts

Prompt gamma activation analysis (PGAA) is a non-destructive nuclear analytical method and is useful to obtain the bulk elemental composition of materials. We conducted PGAA for the source rocks of Korean obsidian artefacts. It has been reported that there exist lots of microlites inside the obsidian artefacts. When the uneven distribution of microlites is prominent, bulk analysis rather than spot analysis is preferable to the provenance study of obsidian artefacts. We compared two bulk analytical methods for obsidian: the correlation between the analytical results of PGAA and wavelength dispersive X-ray fluorescence analysis (WDXRF) has been examined. We have found that the major oxide contents from the PGAA are in good accordance with those from the WDXRF except for MnO. Using the PGAA data, we investigated the geochemical contrast between the two kinds of source rocks of the Korean obsidian artefacts and found out that the bulk PGAA data can be used as a good discriminator of the two distinct sources.