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Aims: The 11-year solar cycle (Schwabe cycle) is the dominant pattern of solar magnetic activity reflecting the oscillatory dynamo mechanism in the Sun’s convection zone. Solar cycles have been directly observed since 1700, while indirect proxy data suggest their existence over a much longer period of time, but generally without resolving individual cycles and their continuity. Here we reconstruct individual solar cycles for the last millennium using recently obtained ¹⁴C data and state-of-the-art models. Methods: Starting with the ¹⁴C production rate determined from the so far most precise measurements of radiocarbon content in tree rings, solar activity was reconstructed in the following three physics-based steps: (1) correction of the ¹⁴C production rate for the changing geomagnetic field; (2) computation of the open solar magnetic flux; and (3) conversion into sunspot numbers outside of grand minima. All known uncertainties, including both measurement and model uncertainties, were straightforwardly accounted for by a Monte-Carlo method. Results: Cyclic solar activity is reconstructed for the period 971–1900 (85 individual cycles) along with its uncertainties. This more than doubles the number of solar cycles known from direct solar observations. We found that the lengths and strengths of well-defined cycles outside grand minima are consistent with those obtained from the direct sunspot observations after 1750. The validity of the Waldmeier rule (cycles with fast-rising phase tend to be stronger) is confirmed at a highly significant level. Solar activity is found to be in a deep grand minimum when the activity is mostly below the sunspot formation threshold for about 250 years. Therefore, although considerable cyclic variability in ¹⁴C is seen even during grand minima, individual solar cycles can hardly be reliably resolved therein. Three potential solar particle events, ca. 994, 1052, and 1279 AD, are shown to occur around the maximum phases of solar cycles. Conclusions: A new approximately 1000-year-long solar activity reconstruction, in the form of annual (pseudo) sunspot numbers with the full assessment of all known uncertainties, is presented based on new high-precision Δ¹⁴C measurements and state-of-the-art models, more than doubling the number of individually resolved solar cycles. This forms a solid basis for new, more detailed studies of solar variability.

The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between 14C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric 14C/12C ratio caused by the 14C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals and Homo sapiens in Eurasia.

The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their 14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 14C curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric 14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric 14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.

Imprecise chronology has entailed a fuzzy kind of prehistory. Prehistorians should no longer be content with timeframes that employ successive units of 200 years or more duration, or with slow change over the long term as their dominant chronological and interpretative perspective. The means to get away from very generalised accounts of the past is formal chronological modelling in a Bayesian framework. The Bayesian approach in general is outlined, with emphasis on its interpretive and iterative nature. The approach combines calibrated radiocarbon dates with knowledge of the archaeological contexts from which they are derived to produce a series of formal, probabilistic date estimates. Stringent demands are made of both the radiocarbon dates and our archaeological understanding of stratigraphy, associations, sample taphonomy and context in general. The Bayesian process at Alsónyék involved assessment of existing dates, careful definition of aims and objectives, the construction of a rigorous sampling strategy, with an explicit hierarchy of suitable samples, precise understanding of the contexts from which samples are derived, and simulation to achieve cost-effective use of resources. The principal material dated at Alsónyék was human and animal bone. Potential age offsets from non-vegetarian diets are carefully considered; ‘perfect pairs’ of human and animal bone samples from the same contexts indicate that human bone samples are not subject to wide-scale freshwater reservoir effects. Dietary inputs are estimated formally using a series of Bayesian mixing models. The sequence of iterative sampling submissions between 2012 and 2015 is described, and the procedures of the five laboratories involved are detailed. Procedures for model construction, validation and comparison are discussed. Finally, we consider how we can use precise timings to reveal the web of connections and successions that made up past lives, adding plot and context to a more precise chronicle to create narratives for peopling the past., Bericht der Römisch-Germanischen Kommission, Bd. 94. 2013 (2016): Bericht der Römisch-Germanischen Kommission

Combining atmospheric ∂14CO2 data sets from different networks or laboratories requires secure knowledge on their compatibility. In the present study, we compare ∂14CO2 results from the Heidelberg low-level counting (LLC) laboratory to 12 international accelerator mass spectrometry (AMS) laboratories using distributed aliquots of five pure CO2 samples. The averaged result of the LLC laboratory has a measurement bias of –0.3±0.5‰ with respect to the consensus value of the AMS laboratories for the investigated atmospheric ∂14C range of 9.6 to 40.4‰. Thus, the LLC measurements on average are not significantly different from the AMS laboratories, and the most likely measurement bias is smaller than the World Meteorological Organization (WMO) interlaboratory compatibility goal for ∂14CO2 of 0.5‰. The number of intercomparison samples was, however, too small to determine whether the measurement biases of the individual AMS laboratories fulfilled the WMO goal.

The excavations at Alsónyék revealed numerous Starčevo features, over 50 in the southern part of subsite 10B and some 500 in subsite 5603. The overwhelming majority of the features uncovered were individual pits and pit complexes. Traces of houses or above-ground structures were recorded, but no certain house plans could be identified; numerous hearths and ovens were found. 25 Starčevo burials have been identified, with some in disused pits and ovens. The occupation excavated in subsite 5603 was substantial, the largest yet discovered in Transdanubia. The north-west distribution of the Early Neolithic cultural complex of the northern Balkans – the Starčevo, Körös and Criş cultures – represents the first food-producing communities in many parts of the Carpathian basin. Starčevo sites are now known in the southern part of western Hungary up to Lake Balaton, but there are many unresolved questions about the precise chronology of the Early Neolithic in Transdanubia and beyond, in the Starčevo-Körös-Criş complex as a whole, and about the character and identity of the first farmers of the region. This paper presents 34 radiocarbon dates from 33 samples, interpreted within a Bayesian framework, for the dating of the Starčevo occupation at Alsónyék. 18 samples of human and animal bone were selected as part of the OTKA-funded project Alsónyék: from the beginnings of food production to the end of the Neolithic in collaboration with the ERC- funded The Times of Their Lives project, in conjunction with 15 existing dates from human burials. The programme aimed to date Starčevo occupation and burials at Alsónyék, and in so doing to contribute to further understanding of the character and pace of the spread of the Neolithic way of life in the region. The Bayesian model presented estimates that Starčevo activity probably began in 5775–5740 cal BC (68% probability), probably lasted for 190–245 years (68% probability), and probably ended in 5560–5525 cal BC (68% probability). The transition from pottery Style group 1 to 2 probably occurred in 5760–5730 cal BC (68% probability), with the transition from pottery Style group 2 to 3 probably in 5595–5570 cal BC (68% probability).The implications of these estimates for the character of the Starčevo occupation at Alsónyék are discussed, as well as for the wider development of the Starčevo culture and of the Early Neolithic in the region as a whole. The current picture suggests the densest Starčevo presence in south-east Transdanubia within the Hungarian distribution of the culture, with a gradual spread to the north later on. The results also demonstrate that Early Neolithic settlements in western Hungary lasted for a substantial period of time, across several human generations., Bericht der Römisch-Germanischen Kommission, Bd. 94. 2013 (2016): Bericht der Römisch-Germanischen Kommission

The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the 'bipolar seesaw'). Here we exploit sub-fossil New Zealand kauri trees to report the first securely dated, decadally-resolved atmospheric radiocarbon ((14)C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring (14)C records with marine (14)C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric (14)C offset was close to zero prior to GS-1, before reaching 'near-modern' values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our findings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes.

This paper presents formally modelled date estimates,within a Bayesian chronological frame-work, for the sequence of deposits and material at the great Neolithic tell of Vinca-Belo Brdo near Belgrade, Serbia, on the basis of the first excavations, led by Miloje Vasic (1908-1934). This is part of a three-strand approach to dating the occupation and finds from the tell that is being undertaken as part of The Times of Their Lives project. A total of 85 radiocarbon measurements are now available from known depths through the Vasic sequence at Vinca. A Bayesian chronological model is constructed, using a poisson-process depositional model.

In this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero).

International audience; Radiocarbon dating archaeological bone typically requires 300-1000 mg material using standard protocols. We report the results of reducing sample size at both the pretreatment and 14 C measurement stages for eight archaeological bones spanning the radiocarbon timescale at different levels of preservation. We adapted our standard collagen extraction protocol specifically for

Lycopus is a widespread herbaceous plant, currently part of European flora. Fossil remains of fruits (nutlets or mericarps) attributed to this genus are frequently found in European archaeological and palaeontological sites, being easily preserved in sedimentary deposits. In a worldwide context, the oldest fossils are from the early Oligocene (ca. 30 Ma) of West Siberia, but they become more common in Miocene (23.0–5.3 Ma) records, ranging from West Siberia to Central Europe. In the literature, the Oligocene and Miocene remains (plus a few Pliocene ones) were assigned to fossil-species, whereas the abundant Pliocene and Pleistocene occurrences (5–0.01 Ma) in Europe were mainly assigned to the extant species L. europaeus. The present work is conceived as the result of an ad hoc research team whose task was to revise and summarize the Italian fossil record of Lycopus, assembling palaeobotanical and archaeobotanical data. We herein report ca. 6000 Lycopus nutlets from 61 sites located in nine regions of Northern and Central Italy. Based on the available information on extant species, we detected nine morphological types of nutlets that can be used for the characterisation of fossils. Our analysis suggests that from 4 to 2.6 Ma a single taxon (L. cf. pliocenicus) with L. americanus-type of nutlets occurred in Italy. The first occurrence of the latter morphological type is from the early Oligocene of West Siberia. The available fossils mildly suggest that extant L. americanus could be the descendant of ancient Eurasian plants characterised by the L. americanus-type of nutlets, through expansion of their range to North America. Conversely, the abundant Italian records of the last 0.2 Ma, including remains from archaeological sites, are only referable to the Eurasian species L. europaeus.

Direct radiocarbon dating of human remains is crucial for the accurate interpretation of prehistory. Yet given the scarcity of prehistoric human remains, direct dating is often too destructive for important fossils. The reduction of sample size necessary for dating bone is therefore of great interest to archaeologists, but the confounding factors of molecular preservation and contamination present great challenges to the radiocarbon dating community.This dissertation explores the reduction of sample size for radiocarbon dating Palaeolithic bone at the pretreatment and 14C measurement stages. Methodological tests were carried out on a selection of archaeological bones spanning the breadth of the radiocarbon method at varying levels of preservation. Our standard pretreatment protocol for ~500 mg bone was refined for

The Middle to Upper Palaeolithic transition in Europe witnessed the replacement and partial absorption of local Neanderthal populations by Homo sapiens populations of African origin1. However, this process probably varied across regions and its details remain largely unknown. In particular, the duration of chronological overlap between the two groups is much debated, as are the implications of this overlap for the nature of the biological and cultural interactions between Neanderthals and H. sapiens. Here we report the discovery and direct dating of human remains found in association with Initial Upper Palaeolithic artefacts2, from excavations at Bacho Kiro Cave (Bulgaria). Morphological analysis of a tooth and mitochondrial DNA from several hominin bone fragments, identified through proteomic screening, assign these finds to H. sapiens and link the expansion of Initial Upper Palaeolithic technologies with the spread of H. sapiens into the mid-latitudes of Eurasia before 45 thousand years ago3. The excavations yielded a wealth of bone artefacts, including pendants manufactured from cave bear teeth that are reminiscent of those later produced by the last Neanderthals of western Europe4–6. These finds are consistent with models based on the arrival of multiple waves of H. sapiens into Europe coming into contact with declining Neanderthal populations7,8. Direct dates for human remains found in association with Initial Upper Palaeolithic artefacts at Bacho Kiro Cave (Bulgaria) demonstrate the presence of Homo sapiens in the mid-latitudes of Europe before 45 thousand years ago.

For many of archaeology’s rarest and most enigmatic bone artifacts (e.g. human remains, bone ornaments, worked bone), the destruction of the 500 mg material necessary for direct accelerator mass spectrometry (AMS) dating on graphite targets would cause irreparable damage; therefore many have not been directly dated. The recently improved gas ion source of the MICADAS (MIni CArbon DAting System) offers a solution to this problem by measuring gaseous samples of 5–100 µg carbon at a level of precision not previously achieved with an AMS gas ion source. We present the results of the first comparison between “routine” graphite dates of ca. 1000 µg C (2–3 mg bone collagen) and dates from aliquots of gaseous samples of 14C BP. The technique has great implications for resolving chronological questions for key archaeological artifacts.