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As today, in antiquity the importance of coastal and deltaic environments lay in the sea’s integrating role in the subsistence, resources, and trade opportunities of its people. For the first large towns of the late Bronze/early Iron Age in Central Italy, salt was an indispensable commodity being the only means available to preserve food, both for consumption and trade. It was produced in the coastal areas but the early production sites, techniques employed, and trade are still uncertain/poorly understood. In the southern part of the Tiber delta palaeo-lagoon of Ostia, at the archeological site of Piscina Torta, heaps made of hundreds of thousands of potsherds were found, possibly related to the salt production technique known as briquetage and pointing at the existence of a major early salt production and trading industry. This coastal area likely holds an outstanding record of the Late Holocene paleoenvironmental changes and of the interaction between climatic variations and coastal processes in an area actively modified and adapted by human activity. An intensive coring campaign at the site and subsequent analyses led to the identification of three stages in the development of the lagoon and its palaeo-inlet towards the sea. During the first phase, the lagoon was well connected to the sea and filled with marine sands. Later on, the inlet was blocked by a newly formed beach ridge, and peat accumulation started. During this second stage, the margins of both the lagoon and inlet were characterized by a highly evaporative environment with carbonate precipitation. Most probably, these sediments were used and leached for producing the brine needed for the salt production by briquetage, a method which consists in boiling such brine in typical reddish jars to obtain a salt cake. Furthermore, heaps composed of both inlet fill, and pottery found around the archeological site suggest how the channel connecting the sea with the lagoon may have been modified by anthropic activities. In a last (third) phase, presumably of medieval age, a marine transgression led to inundation of the lagoon and deposition of highly fossiliferous fine textured sediments.In this contribution, we show the results of a detailed geochemical and micropaleontological analysis (benthic foraminifers) of a continuous section sampled in the ancient lagoon of Ostia, in the form of a paleoenvironmental reconstruction of the area before, during and after its human occupation. Radiocarbon dates provide a firm time frame for the palaeo-lagoon evolutionary phases, while grain size analyses performed both on the inlet fill and the sediment heaps found at the site, revealed new details regarding the human modification of the landscape.

Peer reviewed: True, Funder: Big Questions Institute, Annually resolved measurements of the radiocarbon content in tree-rings have revealed rare sharp rises in carbon-14 production. These ‘Miyake events’ are likely produced by rare increases in cosmic radiation from the Sun or other energetic astrophysical sources. The radiocarbon produced is not only circulated through the Earth’s atmosphere and oceans, but also absorbed by the biosphere and locked in the annual growth rings of trees. To interpret high-resolution tree-ring radiocarbon measurements therefore necessitates modelling the entire global carbon cycle. Here, we introduce ‘ ticktack ’ ( https://github.com/SharmaLlama/ticktack/ ), the first open-source Python package that connects box models of the carbon cycle with modern Bayesian inference tools. We use this to analyse all public annual 14 C tree data, and infer posterior parameters for all six known Miyake events. They do not show a consistent relationship to the solar cycle, and several display extended durations that challenge either astrophysical or geophysical models.

Transatlantic exploration took place centuries before the crossing of Columbus. Physical evidence for early European presence in the Americas can be found in Newfoundland, Canada1,2. However, it has thus far not been possible to determine when this activity took place3–5. Here we provide evidence that the Vikings were present in Newfoundland in ad 1021. We overcome the imprecision of previous age estimates by making use of the cosmic-ray-induced upsurge in atmospheric radiocarbon concentrations in ad 993 (ref. 6). Our new date lays down a marker for European cognisance of the Americas, and represents the first known point at which humans encircled the globe. It also provides a definitive tie point for future research into the initial consequences of transatlantic activity, such as the transference of knowledge, and the potential exchange of genetic information, biota and pathologies7,8., Precise dating of wooden artefacts at a Norse settlement in Newfoundland establishes that the Norse were in the Americas in ad 1021.

The Tierra Blanca Joven (TBJ) eruption from Ilopango volcano deposited thick ash over much of El Salvador when it was inhabited by the Maya, and rendered all areas within at least 80 km of the volcano uninhabitable for years to decades after the eruption. Nonetheless, the more widespread environmental and climatic impacts of this large eruption are not well known because the eruption magnitude and date are not well constrained. In this multifaceted study we have resolved the date of the eruption to 431 ± 2 CE by identifying the ash layer in a well-dated, high-resolution Greenland ice-core record that is >7,000 km from Ilopango; and calculated that between 37 and 82 km3 of magma was dispersed from an eruption coignimbrite column that rose to ∼45 km by modeling the deposit thickness using state-of-the-art tephra dispersal methods. Sulfate records from an array of ice cores suggest stratospheric injection of 14 ± 2 Tg S associated with the TBJ eruption, exceeding those of the historic eruption of Pinatubo in 1991. Based on these estimates it is likely that the TBJ eruption produced a cooling of around 0.5 °C for a few years after the eruption. The modeled dispersal and higher sulfate concentrations recorded in Antarctic ice cores imply that the cooling would have been more pronounced in the Southern Hemisphere. The new date confirms the eruption occurred within the Early Classic phase when Maya expanded across Central America., Fieldwork in El Salvador was funded by a grant awarded to G.A.-D. (CONACYT-CB Grant 240447), and we acknowledge logistical support from the following institutions in El Salvador: Ministerio del Medio Ambiente y Recursos Naturales (MARN), Museo Nacional de Arqueología (MUNA), Universidad de El Salvador, and Policía Nacional Civil. V.C.S. and I.S.-P. acknowledge funding from the Natural Environment Research Council (NERC; Grant NE/5009035/1). A.C. acknowledges the Ministero dell’Istruzione dell’Università e della Ricerca project Ash-RESILIENCE. A.S. and M.W.D. acknowledge funding from the European Research Council (ERC) (ECHOES, Grant 714679). M.S. acknowledges funding from the ERC European Union’s Horizon 2020 research and innovation programme (Grant 820047). D.P. acknowledges support from Juan de la Cierva Grant IJCI-2016- 30482. The collection and analysis of the TUNU2013 core was supported by an NSF Division of Polar Programs Grant 1204176 awarded to J.R.M. We thank Walter Hernandez (MARN) and Hugo Díaz Chávez (MUNA) for assistance in the field, Stephen Harris (Department of Plant Sciences, University of Oxford) for identifying the species of the tree that we radiocarbon dated, and Ian Cartwright (School of Archaeology, University of Oxford) for photographing the cross-section of the tree

The Centre for Isotope Research (CIO) at the University of Groningen has operated a radiocarbon (14C) dating laboratory for almost 70 years. In 2017, the CIO received a major upgrade, which involved the relocation of the laboratory to new purpose-built premises, and the installation of a MICADAS accelerator mass spectrometer. This period of transition provides an opportunity to update the laboratory’s routine procedures. This article addresses all of the processes and quality checks the CIO has in place for registering, tracking and pretreating samples for radiocarbon dating. Complementary updates relating to radioisotope measurement and uncertainty propagation will be provided in other forthcoming publications. Here, the intention is to relay all the practical information regarding the chemical preparation of samples, and to provide a concise explanation as to why each step is deemed necessary.

Suids (Sus sp.) played a crucial role in the transition to farming in northern Europe and, like in many regions, in the Netherlands pig husbandry became an important subsistence activity at Neolithic sites. Yet little is known about wild boar palaeoecology and hunting in the Late Mesolithic Netherlands with which to contextualize this transition. This paper presents the first multi-proxy analysis of archaeological suid remains in the Netherlands. It explores human-suid interactions at the Swifterbant culture sites of Hardinxveld-Giessendam Polderweg and De Bruin (5450–4250 BC) through biometric analysis, estimation of age-at-death, and stable carbon and nitrogen isotope analysis. The results reveal targeted hunting of adult wild boar in the Late Mesolithic (5450–4850 BC), with a possible shift over time towards more juveniles. The wild boar in this period are demonstrated to be of comparably large size to contemporary northern European populations and exhibiting a wide range of dietary regimes. In the final occupational period (4450–4250 BC), small suids are present, possibly domestic pigs, but there is no evidence of pig management. This study demonstrates that the nature of human-suid interactions varied over time, which may have been connected to changing environmental conditions, human mobility, and wild boar behaviour. This study also contributes the first biometric and dietary baseline for mid-Holocene wild boar in the Netherlands.

Information about the global climate, the carbon cycle, changes in solar activity, and a number of other atmospheric processes are preserved in the carbon-14 and the beryllium-10 records. However, these isotope datasets are large and cumbersome to work with. We have designed a self-contained, easy-to-use application that allows for more efficient analysis of different periods and patterns of interest. For several applications in atmospheric modelling, a pre-processing stage is applied to the isotope datasets in order to interpolate the data and mitigate their low temporal resolution. In CHRONOscope, we included linear and non-linear methods of interpolation with interactive parameter optimization. The resultant interpolated data can be extracted for further use. The main functionalities of CHRONOscope include the importation and superimposition of external data, quick navigation through the data with the use of markers, expression of the carbon-14 results in both Δ14C and yr BP form, separation of the data by source, and the visualization of associated error bars. We make this free software available in standalone applications for both Windows and Mac operating systems.

While processes involved in the protohistoric briquetage at Puntone (Tuscany, Italy) have been reconstructed in detail, the age of this industry remained uncertain since materials suited for traditional dating (14C dating on charcoal and typological dating of ceramics) were very scarce. We attempted to assess its age by radiocarbon dating organic matter and carbonates in strata that were directly linked to the industry. Microbial DNA and C isotope analyses showed that the organic matter is dominantly composed of labile organic matter, of which the age is coeval with the briquetage industry. Carbonates had a complex origin and were overall unsuited for radiocarbon dating: Shells in process residues exhibited a large, uncertain ‘marine reservoir effect’, hampering their use for dating the industry; the secondary carbonates in these residues had a quite varied composition, including much more recent carbonate that precipitated from infiltrated lateral run-off, as could be concluded from C and Sr isotope analyses. Dates found that were deemed reliable (c. 1000–100 cal BCE) show that this ancient industry, which started in the Late Bronze Age - Early Iron Age (1107–841 cal BCE), extended into the Roman Republican period and was contemporary with the saltern-based larger scale salt industry in Central Lazio.

Rapid increments in the concentration of the radiocarbon in the atmosphere (Delta C-14) have been identified in the years 774-775 CE and 993-994 CE (Miyake events) using annual measurements on known-age tree-rings. The level of cosmic radiation implied by such increases could cause the failure of satellite telecommunication systems, and thus, there is a need to model and predict them. In this work, we investigated several intelligent computational methods to identify similar events in the past. We apply state-of-the-art pattern matching techniques as well as feature representation, a procedure that typically is used in machine learning and classification. To validate our findings, we used as ground truth the two confirmed Miyake events, and several other dates that have been proposed in the literature. We show that some of the methods used in this study successfully identify most of the ground truth events (similar to 1% false positive rate at 75% true positive rate). Our results show that computational methods can be used to identify comparable patterns of interest and hence potentially uncover sudden increments of Delta C-14 in the past. (C) 2019 Elsevier B.V. All rights reserved.

The extent to which climate change causes significant societal disruption remains controversial. An important example is the decline of the Akkadian Empire in northern Mesopotamia ∼4.2 ka, for which the existence of a coincident climate event is still uncertain. Here we present an Iranian stalagmite record spanning 5.2 ka to 3.7 ka, dated with 25 U/Th ages that provide an average age uncertainty of 31 y (1σ). We find two periods of increased Mg/Ca, beginning abruptly at 4.51 and 4.26 ka, and lasting 110 and 290 y, respectively. Each of these periods coincides with slower vertical stalagmite growth and a gradual increase in stable oxygen isotope ratios. The periods of high Mg/Ca are explained by periods of increased dust flux sourced from the Mesopotamia region, and the abrupt onset of this dustiness indicates threshold behavior in response to aridity. This interpretation is consistent with existing marine and terrestrial records from the broad region, which also suggest that the later, longer event beginning at 4.26 ka is of greater regional extent and/or amplitude. The chronological precision and high resolution of our record indicates that there is no significant difference, at decadal level, between the start date of the second, larger dust event and the timing of North Mesopotamia settlement abandonment, and furthermore reveals striking similarity between the total duration of the second dust event and settlement abandonment. The Iranian record demonstrates this region’s threshold behavior in dust production, and its ability to maintain this climate state for multiple centuries naturally.

Multi-proxy analyses of an 8 m sediment core from Lake Hayk, a closed, freshwater lake in the north-central highlands of Ethiopia, provide a record of changing lake level and inferred regional climatic change for the last 15.6 cal ka years. Between ca. 15.6–15.2 cal ka BP, a lowstand was synchronous with Heinrich Event 1 and an intense drought across Eastern Africa. At ca. 15.2 cal ka BP a lake began to develop at the core site in response to wetter conditions, at the onset of the African Humid Period (AHP). However, in contrast to other lakes in eastern Africa, Hayk lake level fell around ca. 14.8 cal ka BP, indicating a climate shift towards aridity. The lake began filling again at ca. 12.3 cal ka BP and reached maximum water depth between ca. 12.0–10.0 cal ka BP. Lake level declined slowly during the Holocene, culminating in the termination of the AHP at Hayk between ca. 5.2–4.6 cal ka BP. In the late Holocene, ca. 2.2–1.3 cal ka BP, Lake Hayk was again deep and fresh with some evidence of short-term lake level variability. The palaeo-record from Lake Hayk indicates that while it experienced, to a broad degree, the same glacial-interglacial dynamics and sub-millennial shifts in climate found in other palaeolimnological records from eastern Africa, there are offsets in timing and rate of response. These differences reflect chronological discrepancies between records, as well as the varying climate sensitivities and site-specific factors of individual lake basins. This record highlights the different responses by lakes in a climatically vulnerable area of Ethiopia.

Distal tephra from the major Somma-Vesuvius Avellino (AV) eruption is widespread in the coastal basins of Southern Lazio (Central Italy). Dated to 1995 ± 10 cal yr BC in 2011, later on doubts arose about the reliability of this frequently cited age. This led to a major effort to date AV tephra holding sections, based on a thorough methodological approach. Various aspects were studied to identify sections yielding reliable 14C ages, including bioturbation, inbuilt age, and variable sediment accumulation rate. Lowered rates upon deposition of tephra, particularly in anoxic marshy environments and attributed to toxic F contents, showed up as sharp increases in pollen density. The ‘sampling error’ was quantified for specific sedimentary environments and derived from coring data and published data on accumulation rates for similar Central Mediterranean sites. Next, two Bayesian analyses were performed, a traditional using the full set of samples and a novel, based on samples that were deemed as suitable (no bioturbation, inbuilt age, etc.) and of which the age was corrected for the sampling error. The age obtained by the novel analysis had the smallest range (1909-1868 cal yr BC), differs about a century, and is virtually identical to the ages published by Passariello et al. (2009) and Alessandri (2019). The earlier found age (2011) is ascribed to a statistical coincidence. The results solve a long debate on the age of the AV eruption, which is the youngest of the three major eruptions in the Central Mediterranean Bronze Age. Ages of the other two, the Agnano Mt Spina (Phlegrean) and FL eruption (Etna), are still uncertain and disputed. This study illustrates the need for a thorough approach in 14C dating tephra holding sediment archives in the Central Mediterranean, and employed a methodology that can be applied in such approach. Attention is called for potentially toxic fluorine concentrations in Campanian tephra, which may have had a serious impact on the contemporary environment and induced chronological hiatuses, but hitherto were not reported for the early tephra.

The radiocarbon (14C) dating facility at the Centre for Isotope Research, University of Groningen went through a major upgrade in 2017 and this included installation of a MICADAS accelerator mass spectrometer (AMS). In the first 18 months, we performed 4000 sample and 3000 reference measurements. A careful evaluation of those measurement results is presented, to characterize the various sources of uncertainty and to ultimately assign, for every sample measurement, a realistic expanded uncertainty. This analysis was performed on the measurements of secondary references and sample duplicates in various phases of their processing steps. The final expanded uncertainty includes both the 14C measurement uncertainties and uncertainties originating from pretreatment steps. Where the 14C measurement uncertainty includes straightforward uncertainties arising from Poisson statistics, background subtraction, calibration on Oxalic Acid II and δ13C correction, the uncertainties originating from pretreatment steps are based on the spread of actual measurement results for secondary references and sample duplicates. We show that the 14C measurement uncertainty requires expansion, depending on the number of processing steps involved prior to a 14C measurement, by a maximum factor of 1.6 at our laboratory. By using these expansion (multiplication) factors, we make our reported uncertainty both more realistic and reliable.

The nature and timing of the shift from the Late Middle Paleolithic (LMP) to the Early Upper Paleolithic (EUP) varied geographically, temporally, and substantively across the Near East and Eurasia; however, the result of this process was the archaeological disappearance of Middle Paleolithic technologies across the length and breadth of their geographic distribution. Ortvale Klde rockshelter (Republic of Georgia) contains the most detailed LMP-EUP archaeological sequence in the Caucasus, an environmentally and topographically diverse region situated between southwest Asia and Europe. Tephrochronological investigations at the site reveal volcanic ash (tephra) from various volcanic sources and provide a tephrostratigraphy for the site that will facilitate future correlations in the region. We correlate one of the cryptotephra layers to the large, caldera-forming Nemrut Formation eruption (30,000 years ago) from Nemrut volcano in Turkey. We integrate this tephrochronological constraint with new radiocarbon dates and published ages in an OxCal Bayesian age model to produce a revised chronology for the site. This model increases the ages for the end of the LMP (∼47.5–44.2 ka cal BP) and appearance of the EUP (∼46.7–43.6 ka cal BP) at Ortvale Klde, which are earlier than those currently reported for other sites in the Caucasus but similar to estimates for specific sites in southwest Asia and eastern Europe. These data, coupled with archaeological, stratigraphic, and taphonomic observations, suggest that at Ortvale Klde, (1) the appearance of EUP technologies of bone and stone has no technological roots in the preceding LMP, (2) a LMP population vacuum likely preceded the appearance of these EUP technologies, and (3) the systematic combination of tephra correlations and absolute dating chronologies promises to substantially improve our inter-regional understanding of this critical time interval of human evolution and the potential interconnectedness of hominins at different sites.

Arctic mining has a bad reputation because the extractive industry is often responsible for a suite of environmental problems. Yet, few studies explore the gap between untouched tundra and messy megaproject from a historical perspective. Our paper focuses on Advent City as a case study of the emergence of coal mining in Svalbard (Norway) coupled with the onset of mining-related environmental change. After short but intensive human activity (1904-1908), the ecosystem had a century to respond, and we observe a lasting impact on the flora in particular. With interdisciplinary contributions from historical archaeology, archaeozoology, archaeobotany and botany, supplemented by stable isotope analysis, we examine 1) which human activities initially asserted pressure on the Arctic environment, 2) whether the miners at Advent City were "eco-conscious," for example whether they showed concern for the environment and 3) how the local ecosystem reacted after mine closure and site abandonment. Among the remains of typical mining infrastructure, we prioritised localities that revealed the subtleties of long-term anthropogenic impact. Significant pressure resulted from landscape modifications, the import of non-native animals and plants, hunting and fowling, and the indiscriminate disposal of waste material. Where it was possible to identify individual inhabitants, these shared an economic attitude of waste not, want not, but they did not hold the environment in high regard. Ground clearances, animal dung and waste dumps continue to have an effect after a hundred years. The anthropogenic interference with the fell field led to habitat creation, especially for vascular plants. The vegetation cover and biodiversity were high, but we recorded no exotic or threatened plant species. Impacted localities generally showed a reduction of the natural patchiness of plant communities, and highly eutrophic conditions were unsuitable for liverworts and lichens. Supplementary isotopic analysis of animal bones added data to the marine reservoir offset in Svalbard underlining the far-reaching potential of our multi-proxy approach. We conclude that although damaging human-environment interactions formerly took place at Advent City, these were limited and primarily left the visual impact of the ruins. The fell field is such a dynamic area that the subtle anthropogenic effects on the local tundra may soon be lost. The fauna and flora may not recover to what they were before the miners arrived, but they will continue to respond to new post-industrial circumstances., European Union (EU); Horizon 2020; European Research Council (ERC) Grant; ECHOES; Netherlands Organisation for Scientific Research (NWO)

In this article, radiocarbon dating has been used as a tool for investigating the authenticity of two Mesoamerican artefacts from the collection of the National Museum of World Cultures (Museum Volkenkunde), Leiden, the Netherlands. The first artefact is a ceremonial Aztec, possibly a tecpatl, knife, and it is presumed to date to 1300–1500 CE. The second object is a decorated Mixtec skull, presumed to date to 1400–1520 CE. The efficacy of radiocarbon dating was thoroughly tested in this study, especially in regard to the tiny quantities that could be sampled from the skull. However, with the newly revamped radiocarbon facility at the University of Groningen, this was an opportune moment to attempt such research. Ultimately, a credible result could not be obtained on the skull; however, the ceremonial knife was dated reliably to the Aztec period. The article also discusses the broader issue of whether radiocarbon results can be used as a definitive proof of authenticity and examines the risk-reward nature of radiocarbon testing.

In the fourth and fifth centuries AD, the Anglo‐Saxon style was introduced in north‐western Europe. To what extent immigrants contributed to this process for each region is still debated. How and when the Anglo‐Saxon style spread is essential in this debate. Handmade pottery is the most common find category, but so far it can only be dated globally. An earlier and a later style have been postulated and the introduction of this pottery is seemingly not simultaneous in every region. Hitherto this could not be supported by the radiocarbon dates.The present study shows that, with the help of Bayesian modelling, it is possible to substantiate these patterns, which is of utmost importance for understanding migration patterns, contacts and exchange along the southern North Sea coastal regions during this period.

The new IntCal20 radiocarbon record continues decades of successful practice by employing one calibration curve as an approximation for different regions across the hemisphere. Here we investigate three radiocarbon time-series of archaeological and historical importance from the Mediterranean-Anatolian region, which indicate, or may include, offsets from IntCal20 (~0–22 14C years). While modest, these differences are critical for our precise understanding of historical and environmental events across the Mediterranean Basin and Near East. Offsets towards older radiocarbon ages in Mediterranean-Anatolian wood can be explained by a divergence between high-resolution radiocarbon dates from the recent generation of accelerator mass spectrometry (AMS) versus dates from previous technologies, such as low-level gas proportional counting (LLGPC) and liquid scintillation spectrometry (LSS). However, another reason is likely differing growing season lengths and timings, which would affect the seasonal cycle of atmospheric radiocarbon concentrations recorded in different geographic zones. Understanding and correcting these offsets is key to the well-defined calendar placement of a Middle Bronze Age tree-ring chronology. This in turn resolves long-standing debate over Mesopotamian chronology in the earlier second millennium BCE. Last but not least, accurate dating is needed for any further assessment of the societal and environmental impact of the Thera/Santorini volcanic eruption.

In 2018 Pearson et al. published a new sequence of annual radiocarbon (14C) data derived from oak (Quercus sp.) trees from Northern Ireland and bristlecone pine (Pinus longaeva) from North America across the period 1700–1500 BC. The study indicated that the more highly resolved shape of an annually based calibration dataset could improve the accuracy of 14C calibration during this period. This finding had implications for the controversial dating of the eruption of Thera in the Eastern Mediterranean. To test for interlaboratory variation and improve the robustness of the annual dataset for calibration purposes, we have generated a replicate sequence from the same Irish oaks at ETH Zürich. These data are compatible with the Irish oak 14C dataset previously produced at the University of Arizona and are used (along with additional data) to examine inter-tree and interlaboratory variation in multiyear annual 14C time-series. The results raise questions about regional 14C offsets at different scales and demonstrate the potential of annually resolved 14C for refining sub decadal and larger scale features for calibration, solar reconstruction, and multiproxy synchronization.

We undertook a strengths, weaknesses, opportunities, and threats (SWOT) analysis of Northern Hemisphere tree-ring datasets included in IntCal20 in order to evaluate their strategic fit with the demands of archaeological users. Case studies on wiggle-matching single tree rings from timbers in historic buildings and Bayesian modeling of series of results on archaeological samples from Neolithic long barrows in central-southern England exemplify the archaeological implications that arise when using IntCal20. The SWOT analysis provides an opportunity to think strategically about future radiocarbon (14C) calibration so as to maximize the utility of 14C dating in archaeology and safeguard its reputation in the discipline., Radiocarbon, 62 (4), ISSN:0033-8222

Intra-annual offsets in Northern Hemisphere atmospheric radiocarbon levels challenge and complicate Old World radiocarbon dating., A single Northern Hemisphere calibration curve has formed the basis of radiocarbon dating in Europe and the Mediterranean for five decades, setting the time frame for prehistory. However, as measurement precision increases, there is mounting evidence for some small but substantive regional (partly growing season) offsets in same-year radiocarbon levels. Controlling for interlaboratory variation, we compare radiocarbon data from Europe and the Mediterranean in the second to earlier first millennia BCE. Consistent with recent findings in the second millennium CE, these data suggest that some small, but critical, periods of variation for Mediterranean radiocarbon levels exist, especially associated with major reversals or plateaus in the atmospheric radiocarbon record. At high precision, these variations potentially affect calendar dates for prehistory by up to a few decades, including, for example, Egyptian history and the much-debated Thera/Santorini volcanic eruption.

The rise of ancient genomics has revolutionised our understanding of human prehistory but this work depends on the availability of suitable samples. Here we present a complete ancient human genome and oral microbiome sequenced from a 5700 year-old piece of chewed birch pitch from Denmark. We sequence the human genome to an average depth of 2.3× and find that the individual who chewed the pitch was female and that she was genetically more closely related to western hunter-gatherers from mainland Europe than hunter-gatherers from central Scandinavia. We also find that she likely had dark skin, dark brown hair and blue eyes. In addition, we identify DNA fragments from several bacterial and viral taxa, including Epstein-Barr virus, as well as animal and plant DNA, which may have derived from a recent meal. The results highlight the potential of chewed birch pitch as a source of ancient DNA., Birch pitch is thought to have been used in prehistoric times as hafting material or antiseptic and tooth imprints suggest that it was chewed. Here, the authors report a 5,700 year-old piece of chewed birch pitch from Denmark from which they successfully recovered a complete ancient human genome and oral microbiome DNA.

To achieve a reliable radiocarbon (14C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as adhesives, varnishes or consolidants can pose a particular challenge to 14C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called Chromosorb® was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable 14C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives.

Extreme cosmic radiation events occurred in the years 774/5 and 993/4 CE, as revealed by anomalies in the concentration of radiocarbon in known-age tree-rings. Most hypotheses point towards intense solar storms as the cause for these events, although little direct experimental support for this claim has thus far come to light. In this study, we perform very high-precision accelerator mass spectrometry (AMS) measurements on dendrochronological tree-rings spanning the years of the events of interest, as well as the Carrington Event of 1859 CE, which is recognized as an extreme solar storm even though it did not generate an anomalous radiocarbon signature. Our data, comprising 169 new and previously published measurements, appear to delineate the modulation of radiocarbon production due to the Schwabe (11-year) solar cycle. Moreover, they suggest that all three events occurred around the maximum of the solar cycle, adding experimental support for a common solar origin.

The emergence of mobile herding lifeways in Mongolia and eastern Eurasia was one of the most crucial economic and cultural transitions in human prehistory. Understanding the process by which this played out, however, has been impeded by the absence of a precise chronological framework for the prehistoric era in Mongolia. One rare source of empirically dateable material useful for understanding eastern Eurasia’s pastoral tradition comes from the stone burial mounds and monumental constructions that began to appear across the landscape of Mongolia and adjacent regions during the Bronze Age (ca. 3000–700 BCE). Here, along with presenting 28 new radiocarbon dates from Mongolia’s earliest pastoral monumental burials, we synthesise, critically analyse, and model existing dates to present the first precision Bayesian radiocarbon model for the emergence and geographic spread of Bronze Age monument and burial forms. Model results demonstrate a cultural succession between ambiguously dated Afanasievo, Chemurchek, and Munkhkhairkhan traditions. Geographic patterning reveals the existence of important cultural frontiers during the second millennium BCE. This work demonstrates the utility of a Bayesian approach for investigating prehistoric cultural dynamics during the emergence of pastoral economies. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Radiocarbon dating is rarely used in historical or contact-era North American archaeology because of idiosyncrasies of the calibration curve that result in ambiguous calendar dates for this period. We explore the potential and requirements for radiocarbon dating and Bayesian analysis to create a time frame for early contact-era sites in northeast North America independent of the assumptions and approximations involved in temporal constructs based on trade goods and other archaeological correlates. To illustrate, we use Bayesian chronological modeling to analyze radiocarbon dates on short-lived samples and a post from four Huron-Wendat Arendarhonon sites (Benson, Sopher, Ball, and Warminster) to establish an independent chronology. We find that Warminster was likely occupied in 1615–1616, and so is the most likely candidate for the site of Cahiagué visited by Samuel de Champlain in 1615–1616, versus the other main suggested alternative, Ball, which dates earlier, as do the Sopher and Benson sites. In fact, the Benson site seems likely to date ~50 years earlier than currently thought. We present the methods employed to arrive at these new, independent age estimates and argue that absolute redating of historic-era sites is necessary to accurately assess existing interpretations based on relative dating and associated regional narratives.

Syphilis was perceived to be a new disease in Europe in the late 15th century, igniting a debate about its origin that continues today in anthropological, historical, and medical circles. We move beyond this age-old debate using an interdisciplinary approach that tackles broader questions to advance the understanding of treponemal infection (syphilis, yaws, bejel, and pinta). How did the causative organism(s) and humans co-evolve? How did the related diseases caused by Treponema pallidum emerge in different parts of the world and affect people across both time and space? How are T. pallidum subspecies related to the treponeme causing pinta? The current state of scholarship in specific areas is reviewed with recommendations made to stimulate future work. Understanding treponemal biology, genetic relationships, epidemiology, and clinical manifestations is crucial for vaccine development today and for investigating the distribution of infection in both modern and past populations. Paleopathologists must improve diagnostic criteria and use a standard approach for recording skeletal lesions on archaeological human remains. Adequate contextualization of cultural and environmental conditions is necessary, including site dating and justification for any corrections made for marine or freshwater reservoir effects. Biogeochemical analyses may assess aquatic contributions to diet, physiological changes arising from treponemal disease and its treatments (e.g., mercury), or residential mobility of those affected. Shifting the focus from point of origin to investigating who is affected (e.g., by age/sex or socioeconomic status) and disease distribution (e.g., coastal/ inland, rural/urban) will advance our understanding of the treponemal disease and its impact on people through time.

We present a complete ancient human genome and oral microbiome sequenced from a piece of resinous "chewing gum" recovered from a Stone Age site on the island of Lolland, Denmark, and directly dated to 5,858-5,661 cal. BP (GrM-13305; 5,007+/-11). We sequenced the genome to an average depth-of-coverage of 2.3x and find that the individual who chewed the resin was female and genetically more closely related to western hunter-gatherers from mainland Europe, than hunter-gatherers from central Scandinavia. We use imputed genotypes to predict physical characteristics and find that she had dark skin and hair, and blue eyes. Lastly, we also recovered microbial DNA that is characteristic of an oral microbiome and faunal reads that likely associate with diet. The results highlight the potential for this type of sample material as a new source of ancient human and microbial DNA.

Radiocarbon data suggest the need to reconsider current dates and assumptions for contact-era Iroquoian history., A time frame for late Iroquoian prehistory is firmly established on the basis of the presence/absence of European trade goods and other archeological indicators. However, independent dating evidence is lacking. We use 86 radiocarbon measurements to test and (re)define existing chronological understanding. Warminster, often associated with Cahiagué visited by S. de Champlain in 1615–1616 CE, yields a compatible radiocarbon-based age. However, a well-known late prehistoric site sequence in southern Ontario, Draper-Spang-Mantle, usually dated ~1450–1550, yields much later radiocarbon-based dates of ~1530–1615. The revised time frame dramatically rewrites 16th-century contact-era history in this region. Key processes of violent conflict, community coalescence, and the introduction of European goods all happened much later and more rapidly than previously assumed. Our results suggest the need to reconsider current understandings of contact-era dynamics across northeastern North America.

Papyri 10012A and 10012B from Illahun, Egypt, provide the earliest astro-chronological datum in history and, while calculated to various years in the 19th century BCE, have never been independently verified. As this datum enables the Middle Kingdom (MK) section of Egyptian historical chronology to be anchored in absolute time, it establishes the principal calendrical timeline for the eastern Mediterranean Bronze Age in the first half of the 2nd millennium BCE. AMS radiocarbon measurements of Papyrus 10012B establish its date range to 1886–1750 BCE, confirming the astronomical calculations and the essential reliability of Egyptian historical chronology for this period. Furthermore, all three leading estimates for the calendar year attribution of the document are supported by this analysis, with the role of a possible growing season effect determining which is most favored.

We report a set of radiocarbon data for the Middle Bronze Age monumental building at Tell el-Burak in Lebanon, dating it to the 19th century b.c., and summarize the relevant archaeological informat...

This article presents new radiocarbon evidence from the Middle Bronze Age palatial site of Tel Kabri (Israel). The final phase of the palace (Phase III) can be dated to Middle Bronze Age II, with an end date around the transition from Middle Bronze II to III or very early in Middle Bronze III. According to our14C data, the end of Tel Kabri Phase III (and thus the transition from Middle Bronze II to III) can be dated to ~1700 BC. This date is about 50–100 yr earlier than traditional chronological models for the Middle Bronze Age propose (~1650 BC according to the traditional chronology or ~1600 BC according to the low chronology).14C data from Tel Kabri thus add additional evidence for a higher Middle Bronze Age chronology for the Levant, consistent with recent14C evidence from Tell el-Dabca (Egypt), Tel Ifshar (Israel), and Tell el-Burak (Lebanon).

Plants and animals influence biomass production and nutrient cycling in terrestrial ecosystems; however their relative importance remains unclear. We assessed the extent to which mega-herbivore species controlled plant community composition and nutrient cycling, relative to other factors during and after the Late Quaternary extinction event in Britain and Ireland, when two-thirds of the region’s mega-herbivore species went extinct. Warmer temperatures, plant-soil and plant-plant interactions, and reduced burning contributed to the expansion of woody plants and declining nitrogen availability in our five study ecosystems. Shrub biomass in particular was consistently one of the strongest predictors of ecosystem change, equaling or exceeding the effects of other biotic and abiotic factors. In contrast, there was relatively little evidence for mega-herbivore control on plant community composition and nitrogen availability. The ability of plants to determine the fate of terrestrial ecosystems during periods of global environmental change may therefore be greater than previously thought.

The construction chronology of three of the earliest Dunhuang Mogao Grottoes (Caves 268, 272, and 275) has been the subject of ongoing debate for over half a century. This chronology is a crucial topic in terms of further understanding of the establishment of the Dunhuang Mogao Grottoes, early Buddhism in the Gansu corridor, and its relationship with Buddhism developed in the Central Plains. Building upon archaeological, art historical and radiocarbon (14C) dating studies, we integrate new 14C data with these previously published findings utilizing Bayesian statistical modeling to improve the chronological resolution of this issue. Thus, we determine that all three of these caves were constructed around AD 410–440, suggesting coeval rather than sequential construction.

Between 1500 and 1850, more than 12 million enslaved Africans were transported to the New World. The vast majority were shipped from West and West-Central Africa, but their precise origins are largely unknown. We used genome-wide ancient DNA analyses to investigate the genetic origins of three enslaved Africans whose remains were recovered on the Caribbean island of Saint Martin. We trace their origins to distinct subcontinental source populations within Africa, including Bantu-speaking groups from northern Cameroon and non-Bantu speakers living in present-day Nigeria and Ghana. To our knowledge, these findings provide the first direct evidence for the ethnic origins of enslaved Africans, at a time for which historical records are scarce, and demonstrate that genomic data provide another type of record that can shed new light on long-standing historical questions.

The date of the Late Bronze Age Minoan eruption of the Thera volcano has provoked much debate among archaeologists, not least in a recent issue of Antiquity (‘Bronze Age catastrophe and modern controversy: dating the Santorini eruption’, March 2014). Here, the authors respond to those recent contributions, citing evidence that closes the gap between the conclusions offered by previous typological, stratigraphic and radiometric dating techniques. They reject the need to choose between alternative approaches to the problem and make a case for the synchronisation of eastern Mediterranean and Egyptian chronologies with agreement on a ‘high’ date in the late seventeenth century BC for the Thera eruption.

The Naqada relative chronology provides the main cultural framework for the Predynastic period of ancient Egypt. It was devised in the late nineteenth century by Flinders Petrie to improve understanding of the prehistoric origins of the Egyptian state. Petrie's approach became widely known and formed the basis for the development of seriation. In this study, we test the reliability of the Naqada relative chronology as a dating tool against all the relevant radiocarbon information. The results show that the main blocks of the relative sequence do form a true chronology, but also indicate that the system is much less reliable at the level of individual phases. We discuss the nature of the discrepancies and the broader influence of the relative chronology on current understanding of Early Egypt.

Cedar (Cedrus sp.) wood from two archaeological contexts in Egypt – (i) the First Intermediate Period coffin of Ipi-ha-ishutef, (ii) a funerary boat at the pyramid of Middle Kingdom king Senusret (or Sesostris or Senwosret) III – form floating tree-ring sequences. Since one of the sample sets had been mounted with Elmer's glue products in core-mounts for dendrochronological examination, we investigate whether pretreatment can remove this potential contaminant before 14C dating. We find that even in (unrealistic) cases of extensive glue contamination this can be largely/successfully removed – making it likely that the samples in this study, where, moreover, only wood samples without traces of glue were employed, can provide accurate 14C dates. Dendro-14C-wiggle-matching was then employed to provide precise calendar dates for the two tree-ring sequences. The last extant ring of the Ipi-ha-ishutef coffin lies ca. 2081–2064 BC (95.4% probability), supporting, but refining, its assumed date. In the case of the Senusret III boat, we find a temporary, small, but important offset within the period ca. 2200–1900 BC in contemporary 14C ages between the Levant and central and northern Europe. It is suggested this is likely a result of exaggeration of normal seasonal variations in the uptake of 14C and its latitudinal distribution caused by climate change in the 2200–1900 BC/4200–3900 Cal BP (y2k) interval. A date for the last extant ring of the Senusret III boat is probably around 1898/95–1879/76 BC (95.4% probability) – more consistent with a high Middle Kingdom Egyptian chronology.

Absolute dates for the end of the Early Bronze Age ancient Near East are of crucial importance for assessing the nature and extent of mid- to late 3rd millennium BC transitions in the Near East and their alleged link to the 4.2ka BP climatic event. This article presents a radiocarbon sequence for the Early Bronze Age site of Tell Fadous-Kfarabida (Lebanon) and argues that the end of the Early Bronze III period has to be dated considerably higher than previously estimated. There is no reason to assume that the 4.2ka BP event might have contributed to or even triggered the collapse of the first urban cities in the southern and central Levant. DOI: 10.2458/56.16932

Radiocarbon dates on samples susceptible to inbuilt age are common in the chronological record of many archaeological and environmental sites. Indeed, fragments of charcoal and wood are sometimes the only materials sufficiently well preserved for dating. However, where high-precision estimates are required the extra uncertainty associated with such measurements often renders them unusable. This article tests three Bayesian modeling approaches that are designed to tackle this problem. The findings of our study suggest that successful corrections can be made for the inherent age offsets. The most effective and versatile approach was based on a version of outlier analysis. It is hoped that this method will become more widely employed and enable samples susceptible to inbuilt age to be included in high-precision chronologies. DOI: 10.2458/56.16685

The UNESCO World Heritage site of L'Anse aux Meadows (LAM) in northern Newfoundland is the only undisputed site of pre-1492 presence of Europeans in the Americas. In August 2018, we undertook fieldwork at LAM to sample the peat bog 30 m east of the Norse ruins for a multiproxy paleoenvironmental assessment of Norse settlement. Instead, we encountered a new cultural horizon. Here we report our fieldwork at this iconic site and a Bayesian analysis of legacy radiocarbon data, which nuance previous conclusions and suggest Norse activity at LAM may have endured for a century. In light of these findings, we reflect on how the cultural horizon, containing nonnative ecofacts, may relate to indigenous or Norse activities.

Jaffe et al. (1) present some of the many challenges faced in attempting to integrate climate science and archeological records. We accept that these challenges exist, and thank the authors for their comments. Our response to the four points made by Jaffe et al. (1) follows: [↵][1]1To whom correspondence should be addressed. Email: stacy.carolin{at}earth.ox.ac.uk. [1]: #xref-corresp-1-1

Two recently published sets of radiocarbon dates, one from Mesopotamia and one from Anatolia, gave anomalous results. On the basis of historical analysis, both sets were expected to date to the 7th century BC. However, the 14C results were more than a century older than this. We tested samples from an Egyptian mummy, also historically dated to the 7th century BC, to see if such discrepancies were more widespread at this time. We did not find evidence of such a problem, but the results do provide insights into the reuse of old wood in ancient Egyptian coffins. We include publication of an earlier set of dates from the same mummy and coffin set.

Mantle flow can cause the Earth’s surface to uplift and subside, but the rates and durations of these motions are, in general, poorly resolved due to the difficulties in making measurements of relatively small vertical movements (hundreds of metres) over sufficiently large distances (about 1,000 km). Here we examine the effect of mantle upwelling through a study of Quaternary uplift along the coast of Angola. Using both optically stimulated luminescence on sediment grains, and radiocarbon dating of fossil shells, we date a 25 m coastal terrace at about 45 thousand years old, when sea level was about 75 m lower than today, indicating a rapid uplift rate of 1.8–2.6 mm yr−1 that is an order of magnitude higher than previously obtained rates averaged over longer time periods. Automated extraction and correlation of coastal terrace remnants from digital topography uncovers a symmetrical uplift with diameter of more than 1,000 km. The wavelength and relatively short timescale of the uplift suggest that it is associated with a mantle process, possibly convective upwelling, and that the topography may be modulated by rapid short-lived pulses of mantle-derived uplift. Our study shows that stable continental regions far from the effects of glacial rebound may experience rapid vertical displacements of several millimetres per year.