Compare methods

	X-Ray Fluorescence Sourcing	Lead Isotope Provenance
Field	Archaeology	Archaeology
Family	Process / pipeline	Process / pipeline
Year of origin	2011	2016
Originator	Energy-dispersive XRF; archaeological obsidian sourcing pioneered by Cann & Renfrew, synthesized by M. Steven Shackley	Established in archaeometry through Oxford and other isotope laboratories from the 1960s onward
Type	Elemental analysis for compositional sourcing of artifacts to geological origins	Isotopic provenance of metals, ores, and glazes by lead isotope ratios
Seminal source	Shackley, M. S. (Ed.). (2011). X-Ray Fluorescence Spectrometry (XRF) in Geoarchaeology. Springer.	Renfrew, C., & Bahn, P. (2016). Archaeology: Theories, Methods, and Practice (7th ed.). Thames & Hudson. ISBN: 9780500292105
Aliases	XRF Provenance, Portable XRF Sourcing, pXRF Elemental Analysis, X-Ray Fluorescence Spectrometry	Lead Isotope Analysis, Pb Isotope Provenance, Lead Isotope Sourcing, Metal Provenance by Lead Isotopes
Related	2	2
Summary	X-ray fluorescence (XRF) sourcing identifies where an artifact's raw material came from by measuring its elemental composition. When a sample is irradiated with high-energy X-rays, each element emits secondary X-rays at characteristic energies, and the intensities of these emissions reveal how much of each element is present. Because volcanic glass, clays, and ores from different geological sources carry distinct trace-element signatures, comparing an artifact's composition to a library of source samples can assign it to its origin. As the geoarchaeology volume edited by M. Steven Shackley documents, XRF — including rapid, non-destructive portable instruments (pXRF) — has become a workhorse for sourcing obsidian, and is also applied to ceramics, metals, and other materials. The resulting provenance data drive reconstructions of procurement and exchange.	Lead isotope provenance traces metals — copper, silver, lead, and lead-bearing glazes and pigments — back to the ore deposits from which they were extracted, by measuring the ratios of lead's four naturally occurring isotopes. Three of those isotopes (lead-206, -207, -208) are produced by the slow radioactive decay of uranium and thorium, while lead-204 is primordial, so the isotope ratios of an ore depend on the age and the original uranium, thorium, and lead content of the deposit. These ratios are fixed at the geological scale and are not altered by smelting, so they survive into the finished artifact. As Renfrew and Bahn note in their survey of provenance science, comparing an artifact's lead isotope signature to the isotopic fields of candidate ore deposits can identify, or at least constrain, the source of its metal. The method sits within the broader geoarchaeological toolkit of compositional and isotopic sourcing.