Multivariate analysis based on geochemical, isotopic, and mineralogical compositions of uranium-rich samples

The chemical and isotopic (U, Pb, Sr) signatures for a suite (n = 23) of pristine (gt;80 wt. % UO2) and altered uraninite samples (gt;70-80 wt. % UO2) from various locations worldwide have been determined for the purpose of identifying potential fingerprints for nuclear forensic analysis. The characterization of the uraninite samples included determination of major, minor and trace element contents, Sr, Pb, and U isotopic compositions, and secondary mineral assemblages. Due to the multivariate approach adopted in this study, principal component analysis (PCA) has been employed to allow the direct comparison of multiple variable types. The PCA results indicate that the geological origin (sandstone, metamorphite, intrusive, granite and unconformity) of pristine uraninite can be readily identified utilizing various combinations of major and/or trace element concentrations with isotopic compositions.