Abstract The southwestern Atlantic margin plays a crucial role in understanding ocean circulation, with the Brazil Current (BC) driving surface flow and various water masses (TW, SACW, AAIW, UCDW, NADW, LCDW) influencing different depths. The Santos Basin, a marginal basin formed following the breakup of Gondwana, remains understudied with respect to late Quaternary sedimentary processes, and the recent literature offers conflicting interpretations of sediment sources and depositional processes. Additionally, radiocarbon data for this region are scarce, and calibration uncertainties and regional reservoir effects have limited previous studies. This study compiles a comprehensive radiocarbon dataset (264 datings from 70 sediment cores) for the upper to middle slope of the Santos Basin (120–2000 mbsl), combining published and unpublished data (69 new ages). Previously published ages were recalibrated using Marine20 and SHCal20 curves, applying a regional ΔR correction. The dataset, showing minimal age inversions, provides a robust foundation for future research on late Quaternary sedimentary and paleoenvironmental dynamics in the southwestern Atlantic.

Abstract Burial mounds, or kurgans , are a widespread archaeological feature in ancient Eurasia. In the South Caucasus, the Kura-Araxes (KA) culture adopted these funerary structures to express horizontal social ideology through collective inhumations. KA communities also constantly re-engaged with the dead through the regular reopening of burials, contributing to a rich organic archive that relates to episodes of funerary manipulation. This article reports on the results of a radiocarbon wiggle-match obtained from a semi-burnt branch of Juniperus sp. associated with Kurgan 8 at Uzun Rama (Ganja, Azerbaijan). This structure yielded evidence of burial activity during the KA I phase (ca. 3500–3000/2900 BCE) and the post-KA, the “Early Kurgan” period (ca. 2500–2000 BCE), and the Late Bronze Age (ca. 1500–1150 BCE). The sample came from a wooden structure constructed and then burnt in the ritual closure of the kurgan by fire, marking the final stage of its KA use. The results of the wiggle-match allowed us to produce a close estimate for the felling of the branch, thus providing a refined Terminus Post Quem (TPQ) for the construction of the wooden structure itself and its use within 3204–3174 BCE. These results shed light on finer temporal resolution of burial history not just pertaining to funerary sequences, but also in terms of social engagement with visible landmarks and long-term cultural or generational memory. The results correlate with broader trends observed in other KA kurgans and settlements excavated along the Kura basin, pointing at large-scale landscape (or even historical) reconfigurations across the Kura-Araxes world.

Abstract At ANSTO, we have developed an automated dissolved inorganic carbon (DIC) processing line, known as A-DIC, designed to sequentially process 10 water samples for radiocarbon analysis without any operator intervention. The A-DIC works at ambient pressure using helium (He) gas as a carrier. It includes a water pump capable of drawing adjustable sample volumes between 22-180 mL into a 250 mL reaction vessel. Upon the addition of 5 mL of phosphoric acid to the vessel, the sample is sparged with helium (He) gas at a rate of 45 mL/min for 16 min. The desorbed CO 2 from the sample is then carried along with He through a series of traps: water vapor traps at –75 °C, a sulphur (SO x ) trap containing silver wires at 650 °C, and two CO 2 traps at –196 °C. The A-DIC is automated via a Python script executed on a PC connected via USB. It demonstrates consistent performance and CO 2 trapping efficiency across batches of up to 10 samples. For contamination study, the CO 2 gas collected is transferred to graphitization units to be converted into graphite for AMS analysis.

Abstract The discovery of radiocarbon ( 14 C) 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 14 C content of full rings, as well as their separated earlywood and latewood components. We found that the 14 C 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 14 C 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 14 C pulses. The fast increase coupled with a slower subsequent peak structure suggests similar mechanisms behind the high-latitude observations, i.e., tropospheric 14 C production and/or a fast component of polar air flow across the tropopause combined with the full stratospheric-tropospheric CO 2 exchange. Our results strongly emphasize the need for dynamic carbon cycle models to understand the observed differences between high- and lower-latitude data.

Abstract Long-lived trees support biodiversity at multiple scales, maintain ecosystem functionality, serve as natural archives, and hold cultural and aesthetic value. Despite their importance, the maximum longevity of many tree species remains poorly understood, limiting the design of effective conservation strategies. Challenges in obtaining reliable tree ages are commonly represented by natural wood decay, sampling obstacles, and indistinct or absent annual rings, which prevent or limit the application of tree-ring analyses (dendrochronology). Radiocarbon dating, increasingly accessible and applicable to all species, provides a flexible approach to study tree longevity and its ecological implications. For tropical trees, which mostly lack annual rings, radiocarbon dating is one of the few reliable methods to determine tree ages. Even in sections of the calibration curve characterized by oscillations and plateaus, statistical methods such as wiggle-matching or deposition models may be used to reduce the range of probable tree ages. In this paper, we illustrate a mismatch between tree-ring and radiocarbon-derived estimates of the longevity of angiosperm trees, with tree-ring maximum ages often half of those obtained through radiocarbon dating. We also present the most up-to-date estimates of maximum longevity for 42 arboreal angiosperm species worldwide, based on a literature review. Radiocarbon results indicate that ages of 400–500 years are a common feature of many broadleaved species, while exceptional old ages are restricted to a small minority of individual trees. Our results underscore the need for increased efforts to locate old and ancient trees, investigate their role in ecosystem ecology and ensure their protection.

Abstract We present a short database of the mole fraction of CO 2 and 14 CO 2 in atmospheric air samples from an urban area in Gliwice, Silesia, Poland. The research covered a period from August 2023 to July 2024. A new laboratory air sampler stand was established to monitor carbon dioxide levels in Gliwice, giving the possibility to determine CO 2 levels in the air using appropriate instruments to collect the air samples, extract CO 2 from them, and thus measure carbon isotopes ratio 14 C/ 12 C. The analysis of the mole fraction of CO 2 was determined using a low-cost system (CARBOCAP GMP343), while the carbon isotopes concentration was measured using MICADAS. The 14 C in the air samples varied randomly from –55 to –24‰, while the monthly mole fraction of CO 2 varied from 428 to 470 ppm. It has been also observed also that CO 2 concentration is linked with the planetary boundary layer. The fraction of fossil of total CO 2 has been estimated at the level of 2.5% during the investigated period of time. Another aim of this study was to investigate pine needles as 14 C archives in a contemporary environment. The examination of the needles was based on the analysis of the similarities and differences in radiocarbon concentrations in pine needles of various ages collected in the middle of consecutive seasons, with 3 months resolution in Gliwice. The concentration of 14 C in the needles was determined using a liquid scintillation counter. The mean F 14 C from all the samples was 99.80(70) pMC.

Abstract 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.

Abstract 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 14 C 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.

Abstract 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 14 C 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.

Abstract 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.