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A Synchrotron X-ray Micro-Spectroscopy Study of the Explosive Melt Glass Derived From the Trinity Nuclear Test



Bruce D. Ravel, Daniel E. Crean, Daniel J. Bailey, M. C. Stennett, Claire L. Corkhill, Ryan Tappero, N. C. Hyatt


Trinitite, the explosive melt glass derived from the Trinity nuclear test, is of interest as a model material for nuclear forensics investigation. However, there remains uncertainty as to the mechanism of trinitite formation. In this study, new insight is provided by characterisation of key element (Fe, Cu, K and Ca) distribution and speciation. Using spatially resolved X-ray fluorescence (XRF) and absorption spectroscopies (XAS), heterogeneity in Fe distribution was determined, speciated as Fe(II) exclusively. Contrast between compositional and redox distributions suggests reduction of Fe(III) to Fe(II) before incorporation, consistent with uptake of debris into the explosion fireball. Cu was discovered to be enriched on both the outer surface of the specimen and the surface of inner vesicles, speciated predominantly as Cu(0). This is attributed to condensation on exposed melt surfaces of vaporized Cu components from the nuclear device, during rapid cooling of the trinitite material, establishing a melt temperature above 2868 K. The potassium distribution revealed smooth concentration gradients surrounding internal K-rich hotspots, indicative of diffusive mixing of melted K-minerals. In contrast, sharper concentration gradients surround a Ca-rich domain at the surface, suggesting incorporation during later stages of trinitite formation with rapid cooling. These distributions are evidence of multiple regimes in the formation mechanism of trinitite not previously characterised. More broadly, our investigation highlights the utility of synchrotron radiation techniques for forensic investigation of nuclear and radiological debris.
Geochimica Et Cosmochimica Acta


trinitite, micro-spectroscopy, nuclear forensics


Ravel, B. , Crean, D. , Bailey, D. , Stennett, M. , Corkhill, C. , Tappero, R. and Hyatt, N. (2019), A Synchrotron X-ray Micro-Spectroscopy Study of the Explosive Melt Glass Derived From the Trinity Nuclear Test, Geochimica Et Cosmochimica Acta, [online], (Accessed April 24, 2024)
Created April 28, 2019, Updated October 13, 2022