The recently excavated double church at the site of al-Jumayil (Bishoprich of Madaba, Jordan), devoid of inscriptions, has been tentatively dated to the late 6th century CE, based on stratigraphic evidence, architectural parallels with securely dated churches, and stylistic analysis of mosaic floors. This study aims to advance understanding of the complex’s chronological development through a multidisciplinary approach. The primary methodology involves radiocarbon dating organic inclusions found in the construction mortars used for joint filling and wall coating, alongside an investigation into the mortars’ production technology. The results are integrated with data from previous archaeological excavations and relevant historical sources to refine the site’s chronological framework and address existing gaps in the architectural sequence. The results showed the use of three recipes with varying percentages of organic and inorganic inclusions to produce lime-based white plaster and dark gray mortar coatings and fillings. The results indicate that the complex was constructed in the late 6th to the first half of the 7th centuries CE and underwent stages of ecclesiastical use, destruction, and post-ecclesiastical use before its collapse and abandonment. The results are in good agreement with the regional widespread church construction during the late Byzantine period, a period of regional economic prosperity.

The suitability of marine limpet shells for radiocarbon dating may depend on potential offsets due to diet and habitat, especially with regard to grazing mollusks on carbonate substrates (Dye 1994; England et al. 2013). A previous study on one grazing limpet species on the coast of Ireland found no offsets from carbonate substrates (Allen et al. 2019), but a similar study from mediterranean coasts found significant offsets on carbonate substrates (Ferguson et al. 2011). We carried out a new study of radiocarbon and stable carbon isotopes, using multiple species of mollusks collected live from the coasts of Gibraltar and Sardinia, from both carbonate and non-carbonate substrates. The 14C results indicate that one species, inhabiting the upper shore, has a significant offset at the carbonate locations. This species, Patella rustica, has adapted to tolerate desiccation and may have biological traits that result in higher metabolic-derived carbon incorporated in its shell. The results of this preliminary study imply that selected species of grazing mollusks are suitable for radiocarbon dating, even in areas of carbonate geology.

Chronological studies are pivotal for understanding different dimensions of the past. Latin America has embraced various archaeometric dating methods, including radiocarbon (14C) dating. This article reviews the development and challenges of radiocarbon databases and datasets in Latin America, analyzing their integration with global projects and highlighting regional disparities. While global databases like IntChron and CARD often marginalize Latin American data, local projects such as ArqueoData, AndesC14, MesoRAD, SAAID and ExPaND focus on regional needs. The fragmentation of radiocarbon data across publications, technical reports, and limited-access archives hinders accessibility and collaboration. This article underscores the necessity of transitioning from static datasets to dynamic web applications, utilizing APIs to enhance data interoperability, incorporating FAIR principles (findability, accessibility, interoperability, and reusability). This article proposes embedding Latin American initiatives within stable, local institutions to ensure sustainability, establishing classification standards for both radiocarbon dates and associated archaeological contexts. Interdisciplinary collaboration between archaeologists and computer scientists is crucial to developing robust, interoperable databases. By embracing these strategies, Latin America can bridge technological and economic gaps, strengthening its contribution to global archaeological research and fostering new insights into the region’s past.

The 14C marine reservoir age in the North Atlantic and Norwegian Sea has varied through the late glacial period. Here I present a curve, called Norcoast25, for the calibration of late glacial and Early Holocene marine 14C ages from the Norwegian coast. I also present a table of ΔR values that could be used for the calibration of 14C ages with Marine20. The results are based on paired 14C dates of terrestrial plant fragments and articulated marine shells found in shallow marine deposits on the outer coast of Western Norway. The shells calcified in marine water and the 14C reservoir ages represent the surface water off the Norwegian coast. The ΔR value relative to Marine20 decreases from + 300 14C yr at 14.4 cal ka BP to − 100 14C yr at 14.2 cal ka BP and is constant throughout the Allerød. At the transition to the Younger Dryas (YD) the ΔR value increases, and reaches a maximum in the middle YD of + 80 14C yr. At the YD/Early Holocene boundary, the ΔR value drops 200 14C yr. These late glacial ΔR values from Norway’s west coast are 150–300 14C yr lower than has been reconstructed from 14C-dated sediment cores from the open ocean. The Norcoast25 calibration curve can be uploaded to the OxCal calibration program. A link to the file (Norcoast25.14c) is provided at the end of the paper.

A truncated conical-shaped building constructed using the cyclopean technique, called Talayot 1 or East Talayot, is conserved in the Talayotic settlement of Sant Agustí Vell. The monument has an internal chamber with two polylithic columns and a pilaster that helps holding up a roof made of large stone slabs, below which three well-conserved wooden beams can be seen, as well as the remains of two other beams, only one end of each is conserved. The study of a sample of each of these beams extracted from the outer rings of the trunks enable us to determine that all the beams come from the Olea europea L. (olive tree) species. The radiocarbon dating of the samples suggest that the trees from which the trunks come were felled between 1259–1123 cal BC. It was the first time that construction elements of a Menorcan talayot could be dated.

Archaeological investigations in the Prut-Dniester region during the Roman Imperial Period have yielded numerous Sarmatian culture necropolises and isolated graves. Establishing a precise chronology for these remains has long been a challenge due to the limitations of typological dating alone. This study integrates radiocarbon (14C) analysis of 11 human bone samples from selected funerary contexts with traditional typological methods, refining the chronological framework of the Sarmatian culture in this region. The radiocarbon analyses were subjected to Bayesian modeling, which allowed for the delineation of these samples into distinct phases, thereby adjusting and improving the periodization established through traditional methods. The results not only confirm but also refine previously established chronologies, offering deeper insights into the cultural, social, and economic dynamics of Sarmatian communities in the Prut-Dniester Barbaricum. These findings represent a significant contribution to the broader understanding of the Roman Imperial Period beyond the Eastern Limes.

This research presents AMS radiocarbon dating results obtained from recently excavated burials and dwellings at three sites—Xiaxinguang, Wulasitai, and Daxigougoukou—located in the Wulasitai Valley of the Middle Tian Shan Mountains and attributed to the Chawuhu culture. The Bayesian modeling of these data yields a high-resolution chronological framework for Early Iron Age activity in the valley. The results identify a tripartite sequence comprising an Early Stage (cal 900–750 BC), a Middle Stage (cal 750–400 BC), and a Late Stage (cal 400–100 BC), with potential continuity into the turn of the Common Era. The δ13C and δ15N values suggest C3 plant–based diets with moderate animal protein intake, though some individuals show nearly pure plant consumption. Furthermore, through the integration of radi ocarbon data and contextual analysis, the research underscores that the Early Stage of the Chawuhu culture was contemporaneous with the Early Iron Age occupations of eastern Kazakhstan and the Altai region. Particular attention is drawn to the significance of residential graves at Xiaxinguang and Daxigougoukou, where child burials were intentionally integrated into domestic architecture, reflecting complex social and ritual practices. Additionally, radiocarbon evidence indicates that the transition from single to multiple interments occurred between the Early and Middle Stages. These discoveries offer important insights into settlement organization, mortuary practices, and cultural dynamics in the region during the Early Iron Age.

Studies with multiple radiocarbon dates often contain useful information on the relative locations of the dated levels. Such information can be used to obtain robust, integrated site chronologies, with at times more precise ages than those of the individual dates, where outliers can be identified and downweighted, and where the ages of any undated levels can also be estimated. Examples include trees with radiocarbon dates separated by exactly known amounts of yearly tree-rings, or sedimentary sites where ages further down the stratigraphy can be assumed to be older than ages further up. Here we present coffee, an R package for Bayesian models that apply chronological ordering for fossils and environmental events. Coffee runs natively within the popular and versatile R environment, with no need for importing or exporting data or code from other programs, and works with plain-text input files that are relatively easy to read and write. It thus provides a new, transparent and adaptable educational and research platform designed to make chronology building more accessible.

The study provides a radiocarbon sequence for the Iron Age occupation in the elevated areas of the Phoenician settlement of Lisbon, located in the Tagus estuary (Portugal). The dataset is based in ten animal and human samples recovered during archaeological excavations at Largo de Santa Cruz do Castelo. These samples are associated with distinct phases of the Iron Age, dated by the ceramic findings between the 7th and 5th century BCE, as well as a latter sample from the Roman Republican Period (2nd half of the 2nd century BCE). Despite the challenges posed by the 1st millennium BCE radiocarbon calibration, this dataset proves valuable for establishing a more detailed chronological framework. It represents a significant contribution to refining the timeline of Lisbon’s Iron Age settlement and provides a stronger basis for interpreting local developments within the broader regional context.

Recent archaeological studies carried out at Morro de Arica, on the Pacific coast of the south-central Andean area, traditional burial core of the Chinchorro culture (∼7000−3000 cal BP), have enabled a comparative analysis of radiocarbon dates from burial and domestic spaces, considering the differences between dated marine and terrestrial samples. Consequently, we refined the chronological sequence of the Chinchorro culture and obtained a delta reservoir effect of up to 176±113 years, allowing for interpretation of the impact of stratigraphic alterations and pottery fills on the archaeological site’s formation.

The results of radiocarbon dating of modern fish bone collagen from the Upper Lena River have identified a large and highly variable freshwater reservoir effect, with a maximum offset age of 2389 ± 19 14C yr BP. Variable contributions from both dissolved bedrock carbonate and permafrost soil melt were identified as the drivers for these reservoir offsets using a combination of bulk and amino acid specific stable carbon and nitrogen isotopes, as well as the novel application of strontium isotope ratios (87Sr/86Sr) to the study of reservoir effects. Strontium isotope ratios were used as a means of identifying the contributions of dissolved limestone and dolostone carbonate to the fish tissues in comparison to their associated radiocarbon (14C) offset ages. An updated model for δ13C and 14C age offsets in fish bone collagen was produced to interpret the potential combined contributions of old carbon from both permafrost soil melt and carbonates from bedrock erosion. The wide range of 14C offset ages identified in this study poses challenges to producing robust corrections for both modern and archaeological reservoir effects in human populations. Specifically, there is a need to address the potentially wide range of 14C ages which fish could represent, rather than using reservoir effect correction models which function best with uniform endmember contributions of old carbon.

Radiocarbon (14C) activity in aquatic environments is usually different from that of the atmosphere, the result being that organisms that grow in these different environments will have different 14C ages, even though they are contemporary. This age offset in marine samples is known as the “marine reservoir effect.” The marine calibration curve takes this effect into account as a global approximation, but local variations due to ocean dynamics and other factors must be individually studied and corrected for. With a littoral of more than 11,000 km and a great interest in dating malacological marine samples, Mexico has scarce local reservoir effect studies. Most of the available data come from studies done in the 1960s and 1990s. In this study, we present new reservoir effect corrections for four sites in the Pacific Ocean with positive ΔR values as expected, and one from the Caribbean Sea with a negative average value of ΔR. The results were obtained by dating known-age shells from the malacological collection of the Natural History Museum Felipe Poey, in Havana, Cuba. This new data will be useful to do more precise reservoir effect corrections to malacological samples of the region, with special interest in contexts where it is difficult to date other kinds of organic samples, due to difficulties in their preservation.

Radiocarbon dating is essential for establishing robust chronologies in archaeological and paleoenvironmental contexts spanning the last 55,000 years. Pottery, pervasive in the archaeological record, offers a crucial framework for dating human activity during the Holocene. Traditionally, radiocarbon dating of pottery has relied on targeting carbonaceous inclusions such as organic temper or measuring stratigraphically associated materials like bone and charcoal. Inaccuracies can arise, however, if the targeted fraction does not reflect the timing of vessel use or if stratigraphic associations are uncertain. An alternative involves radiocarbon dating of lipid residues, particularly fatty acids absorbed into the ceramic matrix during the processing and storage of plant and animal-derived resources. This approach holds promise for delivering highly accurate measurements directly correlating to vessel use. At the Oxford Radiocarbon Accelerator Unit, efforts have been made to develop this methodology through compound-specific radiocarbon dating of pottery, employing a gas chromatography (GC)-preparative fraction collector (PFC) approach. Here, we describe the protocol and present preliminary findings, including analyses conducted on pottery samples sourced from an archaeological site with an established chronology.

The date of the Thera eruption has been a subject of intense debate since the mid-20th century. In recent years, the disagreements have escalated with the introduction of IntCal20. The increased number of annual measurements around the time period of the eruption has highlighted potential fluctuations in the atmospheric radiocarbon record, shedding new light on the date of the disastrous event. The Centre for Isotope Research in Groningen has already contributed data from this time period to IntCal20, and here, we report a new set of annual data of approximately 90 radiocarbon measurements between 1660 and 1507 BCE. We investigate the potential anomalies in the calibration curve and compare our dataset with those from other leading laboratories. Although we do not find compelling evidence of any rapid increases in radiocarbon production during this period, the results do point to the presence of minor differences between datasets which could be species, region or laboratory pretreatment related. By quantifying such offsets, we assess their impact on chronological models related to the eruption of Thera.

The Nerja Cave is a key archaeological site in the Southern Iberian Peninsula. It was inhabited by humans from the Upper Palaeolithic until recent Prehistory (30 and 3.7 ka cal BP). Various excavation campaigns performed in its external chambers (Vestíbulo, Mina and Torca) have recovered evidence of its use as habitat and burial site. Multiple studies on these matters have been published, but, until now, no Bayesian chronological modeling that utilized radiocarbon dates of the three chambers has been performed. To do so, all the available radiocarbon dates and stratigraphic and archaeological data have been compiled. These comprehend ample and diverse information about which, firstly, individual phase models based on the stratigraphic sequence of each one of the chambers have been created. After critically evaluating the results for each of the chambers, a general phase model for the prehistoric occupation of the external chambers has been created considering the cultural adscription of the samples. This has enabled the identification of 11 phases which correspond to the different technocomplexes of the Gravettian, Solutrean, Magdalenian, Epipalaeolithic, Mesolithic, Neolithic and Chalcolithic. Still pending are the refinement and improvement of the model for the Neolithic horizon among other phases of the sequence. The individual and the general models have evidenced important differences between the different archaeological phases in radiocarbon information as well as in the occupation of the three chambers.

The Benedictine Abbey in Tyniec is the oldest existing monastery in Poland (11th cent. AD). The historic walls of the Monastery have survived to this day and crown the limestone hill on the Vistula River. The geological structure of the surrounding area is reflected in the composition of the mortars.

In vicinity of Tyniec one may observe outcrops of Upper Jurassic limestones represented by two facies: bedded limestones with cherts and massive limestones. Recently, it was discovered that the monks not only fortified the Tyniec hill but also partly built it up with loess. Additionally, a massive “stepped” stone platform was later built to strengthen the edge of the hill. The mortars radiocarbon dating provides the first attempt to obtain the wide chronology of the extension of Tyniec. For this purpose, the chronologically oldest layers were analyzed.

Sequential dissolution of mortars was applied to separate the carbonates of different origin. The obtained results illustrated the huge influence of mortar components and the local geological structure on the 14C measurements. In addition to the mortar, 14C measurements were also made for charcoal from Tyniec Abbey. Radiocarbon dating was performed on the selected fractions using accelerator mass spectrometry (AMS). Radiocarbon dating results of samples from the oldest part of the stone platform make it possible to associate its construction with the earliest monastery buildings.

This study presents the initial results of carbon-14 dating after performing sample preparation and graphite production processes at the Federal University of Bahia (UFBA) in an intercomparison with the same processes performed at the Radiocarbon Laboratory of the Fluminense Federal University (LAC-UFF). Both laboratories are located in Brazil. The accelerator mass spectrometry (AMS) system at LAC-UFF was used for radiocarbon measurements. To verify any possible contamination sources during sample preparation, we initially performed swipe tests at UFBA, which were subsequently processed and the graphite samples were produced at LAC-UFF. After UFBA, several reference materials (IAEA-C1, -C2, -C6, -C9, and OXII standards) were prepared and converted into graphite. In addition, the sample material was first partially prepared at UFF and UFBA and then analyzed with the AMS system at LAC-UFF. Subsamples were prepared for additional measurements of the δ13C composition with an elemental analyzer coupled to an isotope ratio mass spectrometer (EA–IRMS) in LFNA-UFBA to study the isotopic fractionation and yield of the graphitization reaction. The obtained values closely aligned with the reference values, demonstrating reproducibility and quality and indicating minimal contamination during chemical and graphitization processes. In the future, samples from different matrices will be prepared at UFBA for application in paleoenvironmental and archaeological studies.

Pahñu is an archaeological site belonging to the Xajay culture, which inhabited north-central Mesoamerica in 350–1000 AD. Human burials contained in three pairs of contiguous cists were discovered inside a ceremonial structure at Pahñu during excavations conducted between 2019 and 2022. The walls of the cists separated groups of skeletal remains, so the stratigraphic units containing them did not overlap. Stratigraphically speaking, the six groups of remains could have been contemporary and each of the cists could have been used during periods of different durations. Therefore, the analysis of excavation data could not produce a precise temporal sequence of the events that took place in the cists. However, radiocarbon dating by accelerator mass spectrometry (AMS) of representative samples of bones, teeth, and charcoal, allowed us to refine the temporal sequence of their placement in each cist and thus have a better understanding of the funerary practices of the Xajay.

Radiocarbon dates have become a cornerstone in archaeological reconstructions of past population dynamics. The increasing reliance on large-scale radiocarbon databases, usually aggregated from diverse sources, however, raises persistent concerns about sampling bias, especially heterogeneous sampling intensity across sites. In this paper, we introduce a rescaling method that adjusts the frequency of dates in radiocarbon datasets in proportion to dwelling counts at the settlement level, using weighting and bootstrap resampling. Through a series of simulations, we show that this approach consistently yields probability distributions that more closely reflect hypothetical population trends, particularly in contexts with high inter-settlement variability in sampling intensity. We apply our method to archaeological data from two areas in Korea, the Yeongsan and Geum River Basins, during the Proto–Three Kingdoms (1C BC–AD 3C) and Three Kingdoms Periods (AD 4–7C). Results demonstrate that rescaled datasets offer significantly different interpretations of population organization and reconfiguration than those derived from original data. This study highlights the importance of addressing sampling heterogeneity in local-scale demographic research and suggests that rescaling is a valuable complement to existing bias-correction strategies in archaeological studies of demography.