Comparisons of ancient mortars and hydraulic cements through in situ analyses by portable X‐ray fluorescence spectrometry

Abstract

A portable X-ray fluorescence spectrometer was used to collect elemental data on various mortars and hydraulic cements at an excavation site near Orvieto, Italy. Four cases are presented that use X-ray fluorescence data to differentiate among mortars: (1) comparison of two mortars on one locus; (2) comparison of two layers of hydraulic cement on one locus; (3) comparison of two hydraulic cement floors; (4) comparison among mortars on five walls from four trenches. The conclusions made from the comparisons aided the site archaeologists in their assessment of the relationships of various loci at the site and establishment of phasing. Elements found in measureable amounts in the mortars and hydraulic cements were Ca, Ti, Mn, Fe, Zn, As, Rb, Sr, Zr, Pb, and Bi. Elements found to be different in the samples and used to differentiate among mortars were Ca, Fe, Zn, Pb, Zr, and Rb. Graphical and statistical data evaluations are presented.

Non‐destructive analysis using PXRF: methodology and application to archaeological ceramics

“…Innovations in X‐ray fluorescence (XRF) technology in recent years have produced a generation of handheld instruments capable of non‐destructive, high‐resolution, multi‐element analysis. Subsequently, there has been a rapid expansion in the application of portable X‐ray fluorescence (PXRF) use in archaeological provenance studies 1–6. However, the analytic parameters that govern the use of miniaturised systems to determine the bulk chemical composition of heterogeneous matrices have not yet been addressed in detail.…”

Characterization of Roman glass tesserae from the Coriglia excavation site (Italy) via energy-dispersive X-ray fluorescence spectrometry and Raman spectroscopy

“…Excavations at this site have been conducted since 2006 under the auspices of the Soprintendenza per I Beni Archeologici dell'Umbria and the Parco Archaeologico e Ambientale dell'Orvietano. Under the direction of David George and Claudio Bizzarri, many artifact types from Coriglia have been identified and chemically analyzed including mortars [21], hydraulic cements [21], hypocaust tiles [22], and fresco pigments [23]. The site at Coriglia has a long history.…”

Differentiation of Hypocaust and Floor Tiles at Coriglia, Castel Viscardo (Umbria, Italy) Using Principal Component Analysis (PCA) and Portable X-ray Fluorescence (XRF) Spectrometry

“…For archaeologists and cultural heritage researchers, nondestructive in situ analyses are an advantageous complement to these traditional analytical approaches in that they require minimal sample preparation, typically utilize shorter analysis times per sample, permit a much more extensive chemical exploration of the sample(s) of interest, and cause little to no destruction of artifacts of the material culture. Portable instrumentation utilized for such in situ studies has included electrochemical impedance spectroscopy, 16 X-ray diffraction, 17,18 Raman spectroscopy, 19,–24 and X-ray fluorescence (XRF) spectrometry, 16,–19,24,–37 with XRF spectrometry increasing in use and applications in recent years due to the availability of a wide array of commercial products.…”

“…Both portable XRF spectrometry and portable Raman spectroscopy have proved to be exceptionally valuable tools at the Coriglia, Castel Viscardo archaeological excavation site near Orvieto, Italy. 19,29,38 Excavations at Coriglia have been directed by David George and Claudio Bizzarri since 2006 under the auspices of the Soprintendenza per I Beni Archeologici dell'Umbria and the Parco Archeologico e Ambientale dell'Orvietano. Mortars, hydraulic cements, lead pipes, drainage system deposit material, ceramics, and fresco pigments have been chemically characterized using these instruments, providing the site's archaeologists with data to augment their observations of the visual characteristics of the site.…”

“…Materials produced by human agency used for construction at a site—mortars, ceramics, and tiles among the most common examples—would likely be produced utilizing the same raw material sources, mixing procedures, and techniques if produced in the same time frame and under the same economic and social conditions and would therefore exhibit similar elemental contents. 4,29,39 XRF spectrometry is well suited for the chemical and statistical differentiation of these types of materials, although portable instrumentation has been utilized for only a limited number of studies to date. 25,29…”