The Iron Age chronology at Arslantepe is the result of the interpretation of Luwian hieroglyphic inscriptions and archaeological data coming from the site and its surrounding region. A new round of investigations of the Iron Age levels has been conducted at the site over the last 10 years. Preliminary results allowed the combination of the archaeological sequence with the historical events that extended from the collapse of the Late Bronze Age empires to the formation and development of the new Iron Age kingdoms. The integration into this picture of a new set of radiocarbon (14C) dates is aimed at establishing a more solid local chronology. High precision 14C dating by accelerator mass spectrometry (AMS) and its correlation with archaeobotanical analysis and stratigraphic data are presented here with the purpose of improving our knowledge of the site’s history and to build a reliable absolute chronology of the Iron Age. The results show that the earliest level of the sequence dates to ca. the mid-13th century BC, implying that the site started developing a new set of relationships with the Levant already before the breakdown of the Hittite empire, entailing important historical implications for the Syro-Anatolian region at the end of the 2nd millennium BC.

The mortar samples of the Castle of Cannero (Lake Maggiore, Italy) have been characterized and radiocarbon (14C) dated. The presence of LDH phases was identified. The hydraulic reaction was evaluated by a multi-analytical approach. Careful extraction, preparation and purification of the binder fraction have been performed. Contaminations due to LDH phases have been removed allowing reliable absolute dating of the structures.

Non-hydraulic lime-based mortars represent only part of the binding materials found in archaeological and historical structures, and a new challenge is the application of 14C dating techniques on mortars that feature hydraulic reactions. This research work aims at 14C dating a series of Mg-rich hydraulic mortars from the Castle of Cannero (Lake Maggiore, Italy), from which both charcoals and mortar samples were collected. A multi-analytical approach employing X-ray powder diffraction (XRPD), optical microscopy (OM), and scanning electron microscopy/energy-dispersive microanalysis (SEM-EDS) was adopted in order to carefully characterize the samples. A wet gravimetric separation for the extraction of the fine fraction mainly composed by the mortar binder was carried out and the binder fraction was characterized by XRPD in order to investigate the presence of contaminants. The binding fractions are characterized by the widespread occurrence of hydrotalcite-type minerals, considered contaminants in 14C dating of mortars because of their capability to exchange carbonate anions even after the hardening process. A further purification treatment by thermal decomposition was performed before 14C dating by AMS. The obtained dates were consistent with archaeological expectations, confirming the potential of the developed purification methodology for hydraulic mortars dating.

In order to radiocarbon (14C) date a building, several components of the mortar could be used, such as the mortar binder, the lime lumps, the charcoal particles and shell fragments eventually present among the aggregates. In particular, the mortar binder requires a purification treatment in order to separate it from other sources of carbon, which could change the 14C signature of the binder invalidating the dating process. Here, we present the application of the Cryo2Sonic method to 14C dating of the ancient building structures unearthed during excavation at the Padua Cathedral complex. The dated samples were pretreated by using Cryo2Sonic method and the improved Cryo2Sonic version 2.0, recently developed by introducing additional steps such as centrifugation of the mortar suspension and gravimetric sedimentation of the binder fractions. The Cryo2Sonic version 2.0 relies heavily on the characterization of the mortar and of the purified binder fractions, allowing the isolation of a reliable 14C datable mortar fraction. Through this new method, the 14C dating of different ancient structures excavated next to the Padua Cathedral allow to identify the first religious complex of the city of Padua (3rd–4th centuries AD).

To date, finding a technique able to effectively isolate the carbon signal from the binder of a mortar is still an open challenge. In this paper, the radiocarbon (14C) dating of one of the most challenging and diffuse types of mortar, the one with pozzolana aggregate, is investigated. Eight mortar samples from three archaeological sites near Rome (Italy) underwent a selection process called Cryo2SoniC. The selected fractions were analyzed by the accelerator mass spectrometry (AMS) 14C technique and compared to known historical references. Additional scanning electron microscopy analysis and petrographic investigations were done, respectively, to check the grain size of the fractions selected by Cryo2SoniC, and further, to characterize the original mortar samples. The masses of carbon yielded from the dated fractions were almost half of those released from some aerial mortars. The 14C dating results were accurate for pozzolana mortars, from buried and unburied structures, with calcination relics and small contamination of secondary calcite. A limitation in the purification protocol was observed on samples with a massive contamination of secondary calcite deposition of ground water origin, occluding porosity and substituting up to the 80% of the original binder matrix.

Absolute dating of mortars is crucial when trying to pin down construction phases of archaeological sites and historic stone buildings to a certain point in time or to confirm, but possibly also challenge, existing chronologies. To evaluate various sample preparation methods for radiocarbon (14C) dating of mortars as well as to compare different dating methods, i.e. 14C and optically stimulated luminescence (OSL), a mortar dating intercomparison study (MODIS) was set up, exploring existing limits and needs for further research. Four mortar samples were selected and distributed among the participating laboratories: one of which was expected not to present any problem related to the sample preparation methodologies for anthropogenic lime extraction, whereas all others addressed specific known sample preparation issues. Data obtained from the various mortar dating approaches are evaluated relative to the historical framework of the mortar samples and any deviation observed is contextualized to the composition and specific mineralogy of the sampled material.

Seven radiocarbon laboratories: Åbo/Aarhus, CIRCE, CIRCe, ETHZ, Poznań, RICH, and Milano-Bicocca performed separation of carbonaceous fractions suitable for 14C dating of four mortar samples selected for the MOrtar Dating Inter-comparison Study (MODIS). In addition, optically stimulated luminescence (OSL) analyses were completed by Milano-Bicocca and IRAMAT-CRP2A Bordeaux. Each laboratory performed separation according to laboratory protocol. Results of this first intercomparison show that even though consistent 14C ages were obtained by different laboratories, two mortars yielded ages different than expected from the archaeological context.

The Ansanto Valley (southern Italy) is characterized by vents and boiling mud lakes that emit typical volcanic exhalations (mostly fossil CO2). This fossil dilution spreads over the Ansanto Valley and its impact on local trees is investigated in this study. Six trees at increasing distance from the emitting sources and 2 aliquots of gas were sampled. Dendrochronological analysis was performed on tree cores in order to check the accuracy of the tree-ring sequences; the results indicate no anomalies in the curves of the analyzed trees. δ13C and radiocarbon (14C) analyses were performed on the α-cellulose extracted from some selected tree rings. The main aim of δ13C analysis was to gain information about the origin of CO2 arising from the source; the results support the hypothesis of a carbonatic origin, with respect to a volcanic origin. 14C analysis was performed to evaluate the influence and to quantify the percentage of fossil dilution characterizing the local atmosphere and affecting the trees at different distances from the source during the years. The results show the presence of a strong fossil dilution affecting the trees, increasing toward the sources (from ∼6% at 80 m distance to ∼30% at 20 m from the nearest vent) with quite stable values over the examined period.

This paper reports the results from applying the Cryo2SoniC (Cryobreaking, Sonication, Centrifugation) protocol to some lime mortars sampled from the citadel of Shayzar (Syria). The overall aims of this project are 1) to use the properties offered by high-precision accelerator mass spectrometry (AMS) radiocarbon dating for the evaluation of absolute chronology with its typical robust time constraints (i.e. 25 14C yr), and 2) to apply the dating directly to the citadel structures in order to prevent possible biasing effects potentially affecting indirect 14C dating on organic materials found at the study site. The analyses presented in this paper have been mainly performed as a preliminary check of the Cryo2SoniC methodology in order to assess its applicability to this study site by comparing observed mortar results with archaeological expectations about the citadel development phasing and charcoals found encased in mortars. Petrographic and mineralogical thin-section analyses by optical microscopy (TSOM), X-ray powder diffraction (XRD), and scanning electron microscopy plus energy dispersive spectroscopy (SEM/EDS) investigations were carried out for characterization of the mortar samples to verify the occurrence of some features, related to their production technology, which may introduce dating offsets. The resulting 14C calibrated ages were in agreement with the archaeological expectations based on type and stratigraphic site reconstructions, in situ inscriptions, and written sources. Such results showed also a general (with 1 exception) statistical agreement among the charcoals and the analyzed mortars simultaneously, confirming the archaeological expectations for the Shayzar citadel. Results presented in this paper indicate good accuracy for the applied procedure for chronology reconstruction and highlight the capability of Cryo2SoniC to further characterize the Shayzar site.

Bone chemical treatment for radiocarbon dating has drawn the attention of different laboratories because dates of bones and charcoals found in the same layer often disagree. Excluding diet-related reservoir effects, this observation is likely due to a nonoptimized procedure of contaminant removal from the extracted collagen. In this study, systematic work on the bone chemical treatment was performed with the aim to investigate the effect of each known procedure (i.e. AAA, GEL, and ULTR) on the collagen used for 14C dating. Isolation and purification of lipids from animal tissues were performed to estimate eventual offsets induced by the applied methods, by comparing the 14C ages of lipids with those of collagen. Moreover, cremated bones were treated for the first time at CIRCE. Measured 14C isotopic ratios on these samples were used to evaluate the accuracy of the applied procedure by comparing against the results for charcoals found in the same archaeological context as the bones.

The Ansanto Valley (southern Italy) is characterized by hydrothermal phenomena, with volcanic gas emissions arising from some vents. In the 1 st millennium BC, a sanctuary dedicated to the goddess Mephitis was built but later destroyed by landslides in the valley. During archaeological excavations in the 1950s, many items were found including wooden artifacts, preserved thanks to the imbibition and subsequent mineralization of the wood tissues due to the gas emissions. Radiocarbon dating of these objects is underway at CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage), in Caserta, Italy. Unfortunately, 2 main problems arise in dating these materials. The first is possible fossil dilution caused by the CO2 emitted from the nearby volcanic vents, which could affect the trees of the valley and also the archaeological materials. In order to determine the magnitude of the fossil dilution in the area, 14C measurements were performed on contemporaneous wood cored from 2 oak trees growing near the vents. 14C values measured in these samples confirmed the presence of a strong fossil dilution in the Ansanto Valley. The second problem is the restoration that the objects underwent during the last century (mostly by using modern organic substances). To investigate suitable pretreatment procedures for removing the restoration materials from the archaeological findings, contemporaneous wood was also analyzed. The wood of trees from the Ansanto Valley and from a distant village (unaffected by the Ansanto fossil dilution) were submitted to the same restoration process applied to the archaeological artifacts, followed by an “artificial weathering” process. Some archaeological materials were also tested for the removal of restoration materials. We subjected the artificially aged trees and the archaeological samples to different chemical processes. Here, we present the results of these processes. Almost all methods turned out to be suitable for the contemporaneous wood, while the results for the archaeological samples remain uncertain. For this reason, more tests are needed, concerning the “artificial weathering,” the restoration, and the chemical procedure for removing the consolidation materials.

The Avellino Pumices eruption was one of the most catastrophic volcanic events of Somma-Vesuvius, which hit prehistoric communities during the Early Bronze Age. In the last 30 yr, several authors reported assessments about its chronology, including radiocarbon datings, but with poor internal agreement and frequently with large experimental errors. A new and more accurate 14C dating of this eruption (1935–1880 BC, 1 σ) was obtained at the CIRCE laboratory in Caserta (Italy) by 3 AMS measurements on a bone sample of a goat buried by the eruption, collected in an Early Bronze Age village at Croce del Papa (Nola, Naples). These results were verified by other measurements on several samples chronologically related to the eruption. Our data show that human resettlement after the eruption occurred rather quickly but lasted only for a short time in areas affected by the volcanic products, like Masseria Rossa and San Paolo Belsito (Nola, Naples), according to 14C dating of archaeological samples collected below and above the eruption deposits. The state-of-the-art chronology of this eruption, emerging from the results obtained in this work as well as from data in the literature, is discussed.

A system with several lines for the preparation of graphite targets for radiocarbon analysis has been built at the new accelerator mass spectrometry (AMS) facility in Caserta, Italy. Special attention has been paid in the design to the reduction of background contamination during sample preparation. Here, we describe the main characteristics of these preparation lines. Results of tests performed to measure 14C background levels and isotope fractionation in several blank samples with the Caserta AMS system are presented and discussed.

Total CO2 exposure levels in a naturally enriched site (Lajatico, Italy) were reconstructed using radiocarbon analysis by accelerator mass spectrometry combined with dendrochronological analysis on wood cores extracted from trees grown in the fossil CO2 source proximity. Over 3 decades (1964–1998), the data show a mean CO2 concentration in the atmosphere of 650 ppm, about twice the current concentration in atmosphere, with a maximum around 1980.