Fuzzy Numbers or Publishable Data? An intra-instrument test of pXRF Calibration Techniques on obsidian from Highland Mexico

Summary

Archaeological applications of portable X-ray Fluorescence Spectrometry (pXRF) have increased over the last decade due to the instruments' low cost, ease of operation, and decreased analysis time. Obsidian provenance studies utilizing pXRF are now a common approach to answering questions regarding resource access and/or trade relationships in many regions and sub-disciplines of archaeology. Despite this increased popularity, the validity and accuracy of this device and the results derived from these analyses are still commonly met with skepticism. We argue that this is due to a misunderstanding of the calibration techniques needed to properly utilize pXRF devices. Here, we discuss a study comparing the results of pXRF analysis of an archaeological obsidian assemblage from highland Mexico using "off the shelf" calibration to those derived from an "altered calibration" using USGS standards. These data were further compared to previously obtained LA-ICP-MS and desktop XRF data obtained from the same assemblage. This study seeks to answer the following questions: (1) How reliable are factory calibration techniques? (2) Is it possible to provenance obsidian from highland Mexico using "off the shelf" calibration? And (3) given these data, what are the larger implications and lessons for archaeologists interested in using pXRF for provenance studies?

This Resource is Part of the Following Collections

• Society for American Archaeology 81st Annual Meeting, Orlando, FL (2016)

Keywords

Spatial Coverage