Between 2021 and 2023, the Center for Applied Isotope Studies (CAIS) tested over 500 samples for biobased carbon content under the United States Department of Agriculture’s (USDA) Biopreferred Program using the American Society for Testing and Materials (ASTM) biobased testing standard D6866. We describe some of the novel approaches we used to prepare a diverse array of biobased products and summarize those radiocarbon test results and success rates in meeting the USDA Minimum Biobased Content (MBC).

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.

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.

Radiocarbon dating by accelerator mass spectrometry (AMS) requires transforming samples into graphite, a step that typically depends on liquid nitrogen and high-purity carrier gases, increasing both cost and operational complexity. We present μGRAPHILINE, a fully automated, modular combustion–graphitization line that removes these dependencies by combining dual-zone combustion with iron–zinc reduction. Performance was evaluated on more than 180 standards and reference materials targets measured on two independent AMS systems. The μGRAPHILINE consistently achieved >90% graphitization yields, stable backgrounds of ∼0.24 pMC (≈48,500 BP), and sample throughput of ∼3.5 hours per target. Reliable operation was demonstrated for a broad sample-size range, from routine 1 mg C down to ∼0.2 mg C, with ion currents sufficient for precise AMS analysis. The system’s automation, modularity, and low memory effect support improved laboratory throughput and operator efficiency. These results indicate that μGRAPHILINE provides a robust and efficient approach to radiocarbon sample preparation with broad potential applications.

In Brazil, laws are being adopted prohibiting the use and distribution of non-recyclable plastic bags and encouraging the use of recyclable, biodegradable and bioplastic bags. However, there is no specific standard method in Brazil to inspect the carbon content of bioplastics. This work aims to implement the sample preparation for radiocarbon biogenic fraction determination in bioplastics in the new radiocarbon laboratory at the Federal University of Bahia (LAPA14C-UFBA). Six plastic samples from Brazilian markets with bio-based seals were collected in regular Brazilian markets, four bags and two tubes. All samples were combusted and graphitized in the LAPA14C-UFBA and the graphites were measured at the Radiocarbon Laboratory (LAC-UFF). The biogenic fraction analysis followed the Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis (ASTM D6866-24). Since the bioplastic manufactured in Brazil is derived from sugarcane, a C4 plant where δ13C values are different from those of petroleum-derived plastic, the biogenic fraction was obtained via the isotopic mixture equation. The results showed a robust direct correlation (r=0.998) between the fractions obtained by the two methods, indicating that δ13C analysis can be used, in this case, as an alternative in determining the biogenic fraction of plastics. From the results obtained, four out of the six samples analyzed showed biogenic fraction values below the 51% required by the I’m Green label, with values ranging from 4% to 43%, according to the δ3C and 14C analysis, showing the efficiency of both techniques in determining the biogenic fraction.

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.

A large-scale outcrop was exposed along the newly constructed road access to the Kumamoto Earthquake Museum “KIOKU” (former Tokai University Aso Campus). Multiple layers of tephra and paleosols cover the Sawatsuno lava (27 ± 6 K-Ar ka) in this outcrop. Three (3) characteristic tephra layers: Kusasenrigahama Pumice (Kpfa: ca. 32.5 cal ka BP) from Kusasenrigahama crater in Aso caldera, Aira Tn (AT: ca. 30 cal ka BP) and Kikai Akahoya (K-Ah: ca. 7.3 cal ka BP) from southern Kyushu are intercalated between thick sandy volcanic ash layers erupted from the post-caldera volcanoes of Aso caldera. Thirteen (13) radiocarbon ages were obtained from soil samples and charcoal fragments. Among these, a sample just below AT shows a younger age, indicating that the upper soil/tephra sequence including AT, was re-deposited on ground surface at the time immediately after ca. 13.4 cal ka BP indicated by this age. This suggests that the duplicated sequence, confirmed by our detailed dating is a product of either near-surface hidden faulting or a small local landslide associated with one of the paleoseismic events similar to the 2016 Kumamoto Earthquake.

Iraya Volcano, situated at the northern tip of Batan Island in the Batanes group, marks the northernmost extent of the Philippine archipelago. Aside from the presence of accessible tephra deposits, the numerous archaeological sites on the island provide key insight into tephrochronology and volcanic hazard assessment. This paper presents stratigraphy and 21 radiocarbon ages of Holocene tephra layers distributed on the island. The eruption ages of the Holocene tephra are approximately 12.4 cal ka BP for Rolling Hills at the bottom, 4.5–4.9 cal ka BP for San Antonio, 2.1–2.5 cal ka BP for Mahatao, 1.6 cal ka BP for Basco, and 1.2–1.6 cal ka BP for Boulder Beach, with most of the tephra concentrated in the latter half of the Holocene. Artifacts excavated from Reydante Cabizon Property Site, San Antonio, Basco can be thought to date to around 4 to 2 cal ka BP, which is consistent with tephrochronology.

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.

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.

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.

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.

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.

This study presents a comparative analysis of the radiocarbon dates obtained on paired samples of various organic materials extracted from a lake sediment core. AMS radiocarbon dating of bulk sediment, chironomid capsules, and Trapa seeds was conducted to assess whether systematic offsets exist in the dates obtained on material that are commonly used to develop chronological frameworks for lake-based paleoenvironmental research. The findings reveal significant discrepancies between 14C dates obtained on bulk sediment, chironomid capsules, and on the Trapa seeds used to develop a previously published age-depth model for a sediment core recovered from Deoria Tal, Garhwal Himalaya, India. The systematic offset between the bulk sediment, and to a lesser extent chironomid remains, and the Trapa seeds is attributed to the integration of allochthonous carbon in the bulk sediment, leading to older apparent ages. The 3.6‰ shift in the δ13C value of the bulk sediment at 252 cm is inferred to reflect an increase in the contribution of C4 plant matter to the lake. The increase in enriched δ13C organic matter, coincident with the increasing offset between the dates obtained on bulk sediment and chironomids, and those obtained on the Trapa seeds, between 800 and 400 cal BP, was likely driven by anthropogenic land use changes, as evidenced by the four-fold increase in Cerealia-type pollen during this interval. This study underscores the necessity of selecting appropriate materials for radiocarbon dating to ensure accurate chronological reconstruction and highlights the potential of using chironomids remains to develop robust radiocarbon chronologies for lake sediment records.

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.

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.

The Pelagatos volcano is situated within the Sierra Chichinautzin Volcanic Field (SCVF), 20 km southeast of Mexico City. Previous radiocarbon (14C) dating has revealed that the age of the Pelagatos volcano ranges from 2.5 ± 0.1 to 14.1 ± 0.2 ka BP (1σ). The analysis of additional cosmogenic radionuclides, such as in situ 10Be, facilitates the confirmation of the geochronology of any geological phenomenon by determining exposure ages in quartz minerals. This study proposes a new chronology for the exposure of the Pelagatos volcano rocks by in situ analysis of 10Be in olivine samples collected from five locations. The average 10Be ages in olivine from Pelagatos rocks range from 3.95 ± 0.97 ka to 5.7 ± 1.4 ka (1σ), with a mean age of 4.6 ± 0.9 ka and 4.9 ± 0.9 ka for flow 1 and flow 2, respectively. These results are consistent with previously reported 14C ages, confirming the reliability of the 10Be exposure ages obtained in this study. The in situ dating of 10Be in olivine minerals presents a viable alternative for elucidating the volcanic history and estimating the timing of the next eruption in this volcanic field.

Within a collaboration between the Brazilian Federal Police and the Radiocarbon Laboratory of the Fluminense Federal University (LAC-UFF), this work studies seized art objects made from ivory. We aim to develop protocols to verify whether they are illegal according to the Convention on International Trade of Endangered Species from Wild Flora and Fauna (CITES) law by measuring the carbon-14 concentration in the modified ivory samples from different sampling spots and comparing it to the bomb peak curve. Over the course of this research, we evaluate the uncertainties related to the determination of the elephants’ death. These uncertainties are due to several factors such as the provenance of the elephants, growth pattern of the tusks and incorporation of atmospheric radiocarbon to the tissues, sampling methods of ivory objects of different sizes and shapes, and radiocarbon data analysis. This work is a pioneer study in Brazil and is likely to become a reference in the country in the field of radiocarbon analyses in forensic contexts.

Using calibrated radiocarbon dates, this study investigates climate signals recorded in fluvial sedimentary archives from southern Poland, eastern Netherlands, and eastern Germany. Summed probability density functions (PDFs) were constructed and analyzed in the context of INTIMATE stratigraphy. The results indicate that fluvial sedimentation and erosion processes were closely linked to climate fluctuations, particularly during GS/GI and GI/GS transitions. The analyses indicate multi-scale relationships between regional geomorphological processes and global climate trends during the period from 50 to 15 cal kBP. This study provides a reconstruction of Late Pleistocene fluvial activity and highlights the need for more precise radiocarbon dates to refine correlations between regional and global climate events.