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.

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.

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.

This paper investigates the everyday use of coins at the Roman Red Sea ports of Berenike and Myos Hormos, challenging their conventional interpretation as mere indicators of trade prosperity. Adopting a contextualized approach, the paper analyzes coin finds alongside non-numismatic evidence – including ceramics, botanical and zoological remains, and epigraphic records – to uncover their role in daily economic activities. The study demonstrates how coins functioned across diverse settings such as marketplaces, industrial zones, religious sites, and residential areas, highlighting their integration into the economic, social, and cultural fabric of the ports. Beyond serving as a medium of exchange, coins played crucial roles in taxation, service payments, and religious offerings. By reconstructing the transactional dynamics of the ancient ports, the paper provides new insights into the interactions between residents and visitors, enriching our understanding of daily life in these vibrant hubs through a holistic archaeological perspective.

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.

The Incas territorial expansion process was motivated not only by ideological, political, and economic factors but also involved the ritual integration of ancient sanctuaries through capacocha offerings. Notable examples include the Sacred Rock (Roca Sagrada) of the Island of the Sun (Lake Titicaca) and the Oracle of Pachacamac (Lurín Valley). The antiquity of these two sanctuaries, combined with their roles as destinations for imperial-scale pilgrimages during the Inca period, underscore their significance and uniqueness and the role of the capacocha ritual to connecting places into the Inca world. The material correlates associated with numerous capacocha rituals recorded in the Andes demonstrate that this ritual adhered to standardized conventions and criteria. The canonical archaeological remains of capacocha are characterized by human sacrifices and specific offerings, particularly anthropomorphic figurines made of precious metals or Spondylus. The absence of human corpses in certain contexts can be attributed to taphonomic factors but also to ritual adaptations specific to the locations where they were discovered. In this article, we develop this adaptive model for two of the major sites of Inca cosmology: Lake Titicaca and Pachacamac, emphasizing their close connection to Cuzco, the imperial capital and center of the Inca world.

Whereas some prehispanic societies across North America pursued monumentality, hierarchy, and regional integration, others adopted inward-oriented strategies that fostered cohesion through symbolic containment and household autonomy. Mimbres Classic period (AD 1000–1130) communities in southwestern New Mexico exemplify this alternative trajectory. By situating Mimbres insularity within broader regional developments, this study examines how material practices were mobilized to construct and maintain a culturally bounded world. Drawing on theories of boundary maintenance and ritual sovereignty, I argue that distinctive forms of architecture, painted ceramics, mortuary practices, and regulated interaction localized sacred authority and deliberately limited external connectivity. In contrast to Chaco Canyon’s investments in monumentality and social hierarchy, Mimbres society sustained social coherence through practices rooted in household ritual and symbolic regulation. Crucially, this insularity was neither fixed nor absolute—it emerged in the AD 900s, peaked during the Classic period, and receded after AD 1130 as communities relocated and engaged with new material traditions and regional networks. By tracing this historical arc, this study challenges models that equate social organization with scale or connectivity, demonstrating instead how inward-oriented strategies can produce resilient, if historically contingent, cultural frameworks.