The Workhorse of Stonehenge Geochemistry

The workhorse of Stonehenge geochemistry is X-ray fluorescence (XRF). To understand why XRF is so useful in the study of Stonehenge, it’s important to understand how the technique works.

How does XRF spectroscopy work?

When a beam of X-rays is directed at a material, the atoms in that material absorb the energy and then re-emit it at wavelengths that are characteristic of each chemical element. In other words, every element has its own spectral fingerprint.² By measuring these emitted X-rays, researchers can determine the elemental composition of a sample quickly, accurately, and — crucially for Stonehenge — without destroying it.²

For most of the twentieth century, XRF was a laboratory technique requiring physical samples. But in recent decades, the development of portable XRF (pXRF) devices has advanced dramatically. These handheld instruments allow researchers to point a spectrometer directly at a stone, even one embedded in an ancient monument, and get a chemical readout on the spot.

This was exactly what a team at the University of Brighton needed when they set out to determine where Stonehenge's sarsen megaliths originated.^3,4 Stonehenge is a highly protected site, and it is simply not possible to take samples from the monument today. As a result, portable XRF was the only viable approach for analyzing the stones in situ.

In the study, the research team applied pXRF analysis to all 52 remaining sarsen uprights and lintel stones at Stonehenge.^3,4 The resulting data was analyzed statistically to identify the degree of chemical variability across the monument.^3,4 The key finding? The vast majority of the sarsens share a strikingly consistent chemistry, strongly suggesting they came from the same source area. Only two stones were chemical outliers.

This consistent chemistry pointed the team towards a specific region. To narrow it down further, they turned to a more powerful laboratory technique called inductively coupled plasma–mass spectrometry (ICP-MS) and compared the sarsen chemistry to stones from 20 different regions across southern Britain.^3,4 The result was a remarkable chemical match with stones from West Woods on the Marlborough Downs, roughly 25 kilometers to the north of Stonehenge.^3,4

As a result, XRF, in both its portable and laboratory forms, provided the chemical backbone for Stonehenge provenance research.

References

1. Wetzel, W. Spectroscopy Around the Globe, Episode 2 – Stonehenge. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/spectroscopy-around-the-globe-episode-2-stonehenge (accessed August 13, 2026).
2. Thermo Fisher Scientific, What is XRF (X-ray Fluorescence) and How Does it Work? Thermo Fisher Scientific, 2026. https://www.thermofisher.com/blog/ask-a-scientist/what-is-xrf-x-ray-fluorescence-and-how-does-it-work/ (accessed August 13, 2026)
3. Nash, D. J.; Ciborowski, T. J. R.; Darvill, T.; Pearson, M.P.; Ullyott, J. S.; Damaschke, M.; Evans, J. A.; Goderis, S.; Greaney, S.; Huggett, J. M.; et al. Petrological and Geochemical Characterization of the Sarsen Stones at Stonehenge. PLoS One 2020, 15 (8), e0236770. DOI: 10.1371/journal.pone.0254760
4. Wetzel, W. Using Portable X-ray Fluorescence Spectrometry (PXRF) to Explore the Origins of the Sarsen Megaliths at Stonehenge. Spectroscopy 2022, 37 (3), 22–23. Available at: https://www.spectroscopyonline.com/view/using-portable-x-ray-fluorescence-spectrometry-pxrf-to-explore-the-origins-of-the-sarsen-megaliths-at-stonehenge