Elemental Composition of Obsidian and Other Lithic Materials as Evidence of Human Trade and Migration

(For expert advice on obsidian composition analysis with Bruker’s handheld XRF, click here.)

Obsidian is an igneous rock with certain special properties that have allowed archeologists and archeological scientists to study it as a means to investigating human trade and migration routes. Obsidian is a glass-like, highly homogenous substance that forms under high heat. The elements present in a sample of obsidian—and their comparative ratios—indicate where an obsidian sample originates geologically, also known as its source or its provenience. The primary elements of importance in sourcing obsidian are rubidium (Rb), strontium (Sr), zirconium (Zr), yttrium (Y), and niobium (Nb). Fe (iron), copper (Cu), zinc (Zn) and a few others play important secondary roles in separating between sources.

Sourcing obsidian is important to archeologists and archeological scientists because the original source of an obsidian sample versus the location where the obsidian is ultimately found by archaeologists holds clues regarding how humans moved and traded in prehistory and early history. The glass-like nature of obsidian made it a material of choice for tool-making, and therefore a valuable trade commodity, so how obsidian moved through the world geographically can provide significant archeological information about what groups or peoples traded with each other, how groups migrated over time, etc. While the homogeneity and unique geological properties of obsidian make it particularly useful for sourcing studies, analysis of other lithics such as basalt can yield similar archeological information. Click here to contact our experts.

XRF for Obsidian Sourcing: The Bruker TRACER 5 Is Purpose-Built for Obsidian Research

Because so much valuable archeological information can be garnered from the elemental analysis of obsidian, archeological scientists and archaeologists are looking for the best tools for easy, inexpensive, meaningful analysis of obsidian. The Bruker Tracer family of handheld XRF analyzers is the perfect tool to meet your obsidian analysis needs. The Bruker TRACER 5 offers the following unique advantages:

  • Fully portable, from remote archeological sites abroad to the university or museum laboratory.
  • Low per-sample cost. Over the course of several hundred samples, the cost per sample is significantly less than sending samples to the laboratory. Moreover, there is no waiting time between the time you send the samples to the lab and the time you receive results.
  • 100% non-destructive analysis. Your sample is not altered in any way, regardless of the number of times it is subjected to analysis.
  • Methodology and software designed specifically for both semi-quantitative and quantitative analysis.
  • Bruker experts who fully understand your specific needs, as well as the nuances of obsidian and obsidian sourcing.

Qualitative/Semi-Quantitative Obsidian Analysis with Bruker's TRACER 5 series

Depending on your obsidian analysis goal, Bruker offers two data processing methods. Qualitative data allows you to unmistakably identify which elements are present in your obsidian sample, and can in turn be used to extract semi-quantitative data: data which—while providing no absolute quantities of an element in any specific units—provides relative quantities of each element of interest so that the ratios of elements present can be compared, charted, and the obsidian source identified or characterized. Beyond the ability to source obsidian by elemental ratios, the semi-quantitative method allows groups of obsidian samples to be separated by source even when the specific source is not known.

Quantitative Obsidian Analysis with Bruker's TRACER 5 series

 Bruker is the only handheld XRF manufacturer to offer an obsidian-specific calibration based on an extensive set of well-characterized globally sourced obsidian samples. Bruker is honored to partner with MURR (Missouri University Research Reactor) Archaeometry Laboratory to calibrate our Tracer instruments to the best, most extensively characterized set of obsidian reference standards anywhere in the world. Point, shoot, and let the calibration do the rest to provide you with quantitative elemental ppm data of your obsidian samples. Click here to contact our obsidian experts.


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