Estudio comparativo de cerámicas arqueológicas ecuatorianas usando XRF (Fluorescencia de Rayos X) y LIBS (Laser – induced Breakdown Spectroscopy).

Abstract

The qualitative composition of archaeological ceramic pieces from three ancestral settlements in Ecuador was analyzed. Two techniques were used: X – Ray Fluorescence (XRF) and Laser – induced Breakdown Spectroscopy (LIBS). In each case, emission spectra were obtained for each sample depending on the constituent elements and concentrations in those samples. An orderly comparison was made between the qualitative results obtained using the LIBS technique and those obtained using the XRF technique. Ultimately, the following elements were identified with both techniques: Ca, K, Fe, Ti, Al, among others.Specifically, in the LIBS spectra, peaks were identified that have “dips” near the central frequency, which was explained by the self – reversal phenomenon. The LIBS spectra data were subjected to Principal Component Analysis to observe groups of samples correlated by common spectral features. In particular, the samples related to settlements on the Ecuadorian coast are mostly grouped around the first principal component, which allowed inferring that, for example, samples such as M3, M7 and M9 have similar values of LIBS intensities corresponding to the spectral lines of calcium, iron and titanium. Repeated patterns (“finger prints”) were identified in the LIBS spectra, which can be implemented as additional identification features in later work.