Characterization of elemental and firing-dependent properties of Phlegrean ceramics by non-destructive ED-XRF and NMR techniques

Abstract

A combination of energy dispersive X-ray fluorescence (ED-XRF) and 2D proton nuclear magnetic resonance ( 1H NMR) relaxometry was employed for the characterization of two groups of similar ceramic fragments from the high-medieval production of the Phlegrean area (Miseno and Cuma, Southern Italy). Both methods are based on the use of non-destructive and portable instruments. This approach allows to correlate complementary microstructural features of ceramics, both dependent and independent of the firing technique. The ED-XRF analysis has shown up the degree of elemental homogeneity of these two ceramic populations and has lead to reasonable hypotheses about continuity in raw clay source utilization and manufacturing methods over the time period of this Phlegrean ceramic production (VI–XIII centuries A.D.), which have proven coherent with literature data. The NMR investigation has allowed to reveal the structural differences among findings, concerning pore space topology and the magnetic attributes of pore walls. Such differences have been associated to the peculiar interplay between temperature and duration of firing and have proven in step with the temperature assignments provided by archaeologists. This way the usefulness of the proposed methodology for the characterization of the microstructural fingerprint of ancient ceramics has been clearly shown and reliable conclusions about the technological evolution of and the mutual influence between the investigated ceramic productions have been drawn.