Laser-induced breakdown spectroscopy (LIBS) offers a means of rapidly distinguishing different geographic sources for a mineral because the LIBS plasma emission spectrum provides information on the chemical composition (i.e. geochemical fingerprint) of a geomaterial. An application of this approach with potentially significant commercial and political importance is the spectral fingerprinting of 'conflict minerals' such as columbite-tantalite ("coltan"). Following a successful pilot study of a columbite-tantalite suite from North America, a more geographically diverse set of 57 samples from 37 locations around the world was analyzed using a commercially available LIBS system. The LIBS spectra were analyzed using advanced multivariate statistical signal processing techniques. Partial Least Squares Discriminant Analysis (PLSDA) resulted in a correct place-level geographic classification at success rates above 90%. The possible role of rare-earth elements (REE's) as a factor contributing to the high levels of sample discrimination was explored. These results provide additional evidence that LIBS has the potential to be utilized in the field as a real-time screening tool to discriminate between columbite-tantalite ores of different provenance.
