A multi-analytical investigation of Corinthian Amphorae from Southern Albania with a Terahertz perspective

The present study focuses on the comparative archaeometric analysis of archaeological ceramic sherds from the sites of Butrint and Çuka e Ajtoit (Southern Albania). Recent excavations at both sites have brought to light numerous fragments typologically identified as Corinthian transport amphorae, dated from the 6th-4th centuries BCE. Transport amphorae are renowned preferential items for investigating the ancient world’s trade and economy: very often they constitute the only tangible trace of exchanges between cultures (Gassner, 2015). The analysis of their composition and the identification of their provenance are fundamental to identify production sites, which is crucial for the reconstruction of ancient trade routes (Quinn, 2013). Finally, characterising the ceramic sherds allows for a prompt identification of ongoing degradation processes, aiding in the correct planning of the conservation strategy and enabling the best-tailored choice of restoration interventions and materials (Quinn, 2013). The focus of our research lies in the thorough characterization of the compositional and technological features of these samples through a multi-analytical approach, aiming to obtain information about their production techniques, the provenance of raw materials and the conservation state. Alongside a traditional approach including Optical Microscopy (OM), Fourier-Transform Infrared Spectroscopy (FTIR), and X-ray Powder Diffraction (XRPD), the innovative application of Terahertz (THz) technologies was integrated. THz applications on ancient ceramics are still scarce in the literature, therefore, this work seeks to address this gap. THz techniques, both spectroscopic and imaging, have seen a remarkable increase in their applications in the neighbouring fields of geosciences, archaeometry, and conservation sciences. This increase is largely due to the particular properties of THz radiation. It lies in a relatively uncharted region of the electromagnetic spectrum, spanning from 1 to 10 THz in frequency and bridging the gap between microwaves and infrared radiation; this region possesses low photon energies (i.e. 4.2 meV at 1 THz), which account for its non-ionizing properties (Huang et al., 2025). These energies excite large-amplitude intermolecular vibrational dynamics in solid-state matter, making THz techniques a powerful yet underexplored tool for the non-invasive and nondestructive characterization of crystalline materials (i.e., inclusions in pottery), especially for their ability to distinguish between polymorphs and to probe microstructural details (Huang et al., 2025). This study presents the spectral and optical characterization of the ceramic sherds obtained using a THz Time-Domain spectrometer, in both reflection and transmission geometries and employing a customized data processing framework while benchmarking the results against ad hoc acquired spectra of reference mineral specimens. Gassner V. (2015) - Le anfore greco-occidentali: riconsiderando la loro evoluzione e l’identificazione dei centri di produzione. Contacts et acculturations en Méditerranée occidentale, https://doi.org/10.4000/books.pccj.4906. Huang H. et al. (2025) - Terahertz Geoscience: THz Time-Domain Spectroscopy for Mineral Materials. Crystal Growth & Design, https://doi.org/10.1021/acs.cgd.4c01423. Quinn P.S. (2013) - Ceramic Petrography: The Interpretation of Archaeological Pottery & Related Artefacts in Thin Section. Archaeopress, https://doi.org/10.2307/j.ctv1jk0jf4.