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.

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.

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.

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.

Holocene environmental changes on the Paraty coastal plain in southeastern Brazil unfolded under dynamic sea-level fluctuations and shifting sedimentary regimes. Continental and marine palynomorph analyses, combined with calibrated radiocarbon dating from two sediment cores (JBS1 and JBS2), reveal a continuous depositional record spanning approximately 7800 to 1000 cal yr BP. Sandy mud and muddy sand sequences reflect variable coastal energy conditions through out the mid to late Holocene. Dinoflagellate cyst assemblages indicate a transition from open marine to marginal marine environments, with maximum marine influence between 7000 and 5000 cal yr BP. Terrestrial palynomorphs show a concurrent shift from grassland-dominated landscapes to mixed vegetation including ombrophilous forest taxa. A marked increase in pollen concentration in the upper stratigraphic layer suggests coastal progradation, enhanced continental input, and reduced marine influence during the late Holocene regression. Bayesian age-depth models demonstrate uninterrupted but variable sedimentation rates, with no evidence for erosional surfaces or depositional hiatuses. The results align with regional sea-level reconstructions and under score the role of transgressive-regressive processes and delta infilling in shaping vegetation dynamics. This integrated micropalaeontological and chronostratigraphic approach offers a robust framework for interpreting Holocene palaeoenvironmental evolution in tropical coastal settings.

Quantifying marine reservoir effects (MREs) across time and space is crucial for establishing accurate archaeological chronologies, including the activities of past hominines. Although the northern Iberian Peninsula shows a high density of Upper Paleolithic sites and marine shells are frequently found in these assemblages, quantification of MREs in this coastal region remains limited. We performed Bayesian modeling of radiocarbon measurements from both terrestrial (Capra pyrenaica, Cervus elaphus and other herbivores unidentified at species level) and marine (Littorina littorea Linnaeus, 1758 and Patella vulgata Linnaeus, 1758 taxa) archaeological samples recovered from the Tito Bustillo cave (Asturias, Spain) in order to determine the ΔR values for northern Iberia during the Lower Magdalenian period (ca. 20–17 ka cal BP). For the time span between 18.6 and 18.2 ka cal BP we estimated ΔR values of –298±44 14C yr and –495±122 14C yr for the periwinkle L. littorea and the common limpet P. vulgata, respectively. This finding has significant implications for future archaeological research in the northern Iberian Peninsula, as researchers must apply distinct ΔR values depending on the mollusk species selected for radiocarbon dating. Furthermore, the consistency between our calculated ΔR value for P. vulgata and previously recorded data for the same taxon from a neighboring coastal region (Cantabria, Spain) suggests remarkable stability in the marine environment of this area during the Lower Magdalenian period.

La Viña rock shelter is a relevant archaeological site for understanding the late Middle and Upper Palaeolithic cultural development in northern Iberia as evidenced by the Mousterian, Aurignacian, Gravettian, Solutrean and Magdalenian bone and lithic industries, parietal engravings and human subsistence remains recovered during the 1980s excavations by J. Fortea in the western and central excavation areas. This paper aims to present 16 new radiocarbon dates, which are added to the previous radiocarbon dates obtained, using different analytical methods on bone and charcoal. These are now 57 dates in total. Bayesian models have been applied to assess and discern the chronology of the archaeological sequence in each sector of the rock shelter. The results provide details on the chronostratigraphy of each excavation area, documenting the duration of the different technocultural phases and confirming in-site postdepositional events.

Welwitschia mirabilis, a unique gymnosperm native to Namibia and Angola, is a keystone plant species in the Namib Desert. It represents the only extremely long-lived non-clonal plant species occurring under hyperarid desert conditions, yet limited attempts have been made to accurately determine its age. Here, we present radiocarbon dates from a dead, sectioned Welwitschia of moderate size. We find the outer caudex tissue growth to progressively increase in age from the leaf base towards the ground level in this dwarf tree, while the inner cortex tissue becomes younger. Our sampling strategy revealed that the oldest tissue from this Welwitschia, found at the base of the caudex in the middle of the lobe, was dated to 531 ± 20 14C years, suggesting a vertical growth rate of approximately 0.47 to 0.67 mm/year. These findings can serve as a basis for future dating of larger, living individuals.

The reduction of anthropogenic methane emissions is a priority due to its potent global warming potential. Radiocarbon (14C) can distinguish between methane from natural biogenic and fossil fuel sources, however, the analysis of methane 14C by conventional accelerator mass spectrometry (AMS) techniques is demanding. At SUERC, a prototype positive ion mass spectrometer (PIMS) is set up to directly analyze 14C in methane with minimal sample preparation. Methane gas was mixed with a stoichiometric amount of oxygen in an open split and admitted directly into the source. A series of modern, blank and unknown methane samples were clearly distinguishable by their 14C/13C raw ratios. The collision cell gas flowrate was then increased to lower the limit of detection. We obtained a corrected 14C/13C raw ratio of less than 2 × 10–13 for blank fossil methane which corresponds to a radiocarbon age greater than 50 kyr. Modern biogenic methane had a measured 14C/13C raw ratio approaching 1 × 10–10 which is consistent with the nominal value of contemporary atmospheric methane. These first results indicate that PIMS has the potential to be a valuable new analytical technique for screening the 14C content of biogas and in climate research studies.

The discovery of radiocarbon (14C) peaks in AD 774–775 and AD 993–994 sparked the search for other anomalous events, leading to the identification of one around 660 BC. However, the ∼660 BC event appears to show a more prolonged increase, raising the question whether the event is qualitatively different. To investigate this, we measured high-latitude tree rings from Finnish Lapland, expected to be highly sensitive to energetic particle events. We measured the 14C content of full rings, as well as their separated earlywood and latewood components. We found that the 14C concentrations start rising already in the latewood of 665 BC and reach almost its full intensity by 664 BC. This rapid increase is similar to that at another high-latitude site (Yamal, Russia) but contrasts with that of low-latitude sites, which show a later peak. The earlier increase of the 14C at high-latitude tree rings compared to lower latitudes is consistent with similar observations for the AD 774 and AD 993 Miyake events. Based on carbon-cycle box modeling, the structure of the subsequent amplitude increase can be explained by either single or double initial 14C pulses. The fast increase coupled with a slower subsequent peak structure suggests similar mechanisms behind the high-latitude observations, i.e., tropospheric 14C production and/or a fast component of polar air flow across the tropopause combined with the full stratospheric-tropospheric CO2 exchange. Our results strongly emphasize the need for dynamic carbon cycle models to understand the observed differences between high- and lower-latitude data.

Estimates of marine reservoir corrections (ΔR) in the southeastern Arabian Sea region are limited. To better constrain the region’s marine reservoir corrections, additional pre-bomb radiocarbon records are needed. In this context, a coral core from the Lakshadweep archipelago in the southeastern Arabian Sea has been analyzed to measure its radiocarbon content. Pre-bomb radiocarbon values from the coral record are used to estimate the marine reservoir correction value of the region. The mean ΔR value of the Lakshadweep region is calculated to be –128 ± 130 yr. The comparison of available ΔR values from the Arabian Sea region shows that the mean ΔR value of the eastern Arabian Sea is significantly lower than that of the northern and western Arabian Sea. The low ΔR values from the eastern Arabian Sea likely indicate the influence of relatively 14C-enriched Bay of Bengal water in the region.

This work aims to clarify the absolute chronology of the construction phases of the St. Peter and Paul Rotunda at Budeč, focusing on the erection of the rotunda and the tower. Fifteen mortar samples were taken from various structural parts, two of which also contained remnants of charcoal. The mortar samples were mechanically treated to extract a purified calcitic binder that was dated by radiocarbon analysis. The effectiveness of the sample pretreatment methodology was assessed by means of cathodoluminescence microscopy. Thin sections of mortars were characterized by polarized light microscopy. The petrographic characterization allowed for the samples to be grouped according to their binder, aggregate, and structure. This was compared with the evaluation of the calibrated dates, expected chronology known from legends, as well as with formal and stylistic analyses of the structure. The radiocarbon dating distinguished the different construction phases well, and the accuracy and reliability of the dating is discussed. The presence of silts and clays probably led to geogenic carbon contamination of the samples from the foundations, as the obtained dates are older than expected. These dating results were thus regarded as inconclusive. However, the samples from the vaulted dome of the rotunda did not show any anomalies, and the calibrated date period obtained was regarded as relevant and thus successfully dated. The dating based on the legends also fits the determined interval.

Antiquities in the Middle East region face various threats, including illicit trade, theft, and forgery. This research examines a leather manuscript obtained by the Palestinian Tourist Police following the arrest of an antiquities smuggler. The manuscript contains Phoenician inscriptions along with symbols such as the Menorah, Shofar, and a plant branch. Radiocarbon dating using accelerator mass spectrometry (AMS) techniques determined the manuscript’s date to be post-1950 CE. Therefore, the results indicate that the manuscript is a modern forgery, likely created for commercial purposes. Additionally, the text contains several grammatical errors, further supporting the conclusion that it is not an authentic historical artifact.

We report the results of radiocarbon dating performed at the ETH laboratory on soft tissue of the mummified body found in September 1991 on the Hauslabjoch in the Ötztaler Alps (near the Similaun Mountain), South Tyrol. Over the past three decades, additional analyses of the sample, which had been stored frozen in a glass jar, have improved the precision of the first published radiocarbon ages. The frozen jar and the story of a mummified body found in the Alps fascinated visitors to the laboratory, mostly primary and high-school students. As part of educational projects, 11 samples were prepared and analyzed, yielding a combined radiocarbon age of 4525 ± 7 BP. This agreement with 4550 ± 27 BP, i.e., the very first results by Bonani et al. (1994), highlights the quality of the analysis performed decades ago. The combined age of all the 14C ages measured at the ETH laboratory is 4527 ± 7 BP.