SEM-EDS characterization of western Mediterranean obsidians and the Neolithic site of A Fuata (Corsica)

Abstract

During the Neolithic, obsidians of the Monte Arci (Sardinia) volcanic complex were by far more used in the northern Tyrrhenian area than those of the three other source-islands (Lipari, Palmarola, Pantelleria) in the western Mediterranean. It is shown that merely determinations of content for six major elements with a scanning electron microscope by energy dispersion spectrometry (SEM-EDS) are sufficient to distinguish the four types of Monte Arci obsidians. Because of the compositional similarities between these obsidian types, a multivariate analysis is recommended in provenance studies. Although SEM-EDS, electron microprobe-wavelength dispersion spectrometry (EMP-WDS) and particle induced X-ray emission (PIXE) give essentially concordant results in the determination of these six element contents, subtle technique-related biases prevent the combination of SEM-EDS, EMP-WDS and PIXE data on source samples for provenance purposes. An SEM-EDS test-study reveals the first occurrence of obsidians of Lipari for the A Fuata Middle to Late Neolithic site of NW Corsica (north of Sardinia), in addition to the usual Monte Arci obsidians. Similar to EMP-WDS, the SEM-EDS technique requires only millimeter-sized fragments.