Mn2+ EPR spectroscopy for the provenance study of natural carbonates

Electron paramagnetic resonance (EPR) spectroscopy as an analytical method in the provenance studies of carbonates, proposed for the first time in 1983 by Cordischi et al. (1983) has become in the past decades a reliable technique, especially when used in the case of marble artifacts. The main descriptor in this investigation was showed to be the Mn2+ spectrum, which consists of a hyperfine structure sextet as well as one or more singlets between the third and the forth sextet lines. In spite of an apparent simplicity, the Mn2+ spectrum of nonirradiated and irradiated carbonates, i.e., calcite and dolomite as well as the corresponding types of marbles or travertine, displays a multitude of characteristics that could be better described by means of the spin Hamiltonian (SH) parameters, where values could be relatively easy determined by an appropriate computer simulation. Different SH parameters such as resonance line half width, fine structure zero field splitting, and g-factors as well as the sixths line shape together with multivariate statistical analysis method such as principal component, factor, or discriminant analysis could be successfully used to discriminate between limestones or marbles coming from different quarries.