Surface and stratigraphic elemental analysis of an ancient Egyptian cartonnage using Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

An archeological Egyptian cartonnage dating back to the Greco-Roman period around the third century BC was elementally analyzed via the sample-friendly technique, Laser-Induced Breakdown Spectroscopy (LIBS). The unique characteristics of LIBS as being a simple and fast technique, has been exploited to obtain surface elemental distribution and depth profiles for the investigated sample. An Nd:YAG laser operating at the fundamental wavelength of 1064 nm has been used as the excitation source along with an echelle spectrometer coupled to an ICCD detector for spectral dispersion and detection. Under the experimental conditions, four distinct regions were studied as ten elements were analyzed for spatial distribution along the surface and also for their depth profiles. Rapid and comprehensive visualization of the investigated regions are provided. The most relevant elements i.e. carbon, calcium, silicon, oxygen and iron suggest that the cartonnage was manufactured via the traditional method, mainly dependent on natural pigments such as metal oxides and calcium carbonate (calcite) which is consistent with the previous results of other conventional techniques used in the field of Archaeology. Supporting studies obtained by both scanning electron microscopy with energy dispersive X-ray micro-analysis (SEM-EDX) and X-ray diffraction (XRD) have been presented for comparison purposes.