The Kastro peninsula constitutes the extension towards the West of Myrina, the Lemnos capital, on the western coast of the island, in the North Aegean Sea. The ongoing research project on rock-cut features and rock-art of this complex site included a five-year (2002–2007) subsurface investigation, during which, among other mobile finds, charcoal and seashell samples were also collected, associated in situ to rock-cut features. Subsequently, in an attempt to bring about information on the dating of the rock-cut site, an investigation based on 14C has also been undertaken. Therefore, the purpose of the present paper is the AMS dating of the unearthed anthropogenic deposits and the calculation of the regional marine reservoir effect during the end of the Late Bronze Age. Our results show that the age of the deposits is spanning from the 13th century BC till the 6th century AD. Moreover, the 14C ages of two pairs of charcoal-seashell samples showed that the mean marine reservoir age R(t) in this region from the 13th to the 10th centuries BC is 175 ± 59 14C yrs and the mean local sea surface reservoir deviation ΔR is found to be –288 ± 108 14C yrs (within 1σ).

This article discusses the absolute chronology of burials from the 3rd and 2nd millennia BC discovered under the mounds of three barrows in the Kordyshiv cemetery in western Ukraine. Its aim is to create a chronological model of the burials by modeling 27 AMS 14C dates obtained from 21 individuals buried in single and collective graves. Dietary analysis of stable carbon (δ13C) and nitrogen (δ15N) isotope values are presented. The Bayesian modeling of the 14C dates from the three Kordyshiv barrows revealed the extremely important role of these monuments as long-term objects used for ritual purposes. At the end of the 3rd millennium BC, the epi-Corded Ware Culture (epi-CWC) community erected a mound over the central burial in Barrow 2, then interred the graves of three additional deceased. After several hundred years Barrow 2 was reused by Komarów Culture (KC) communities from the Middle Bronze Age (MBA) who interred their deceased in the existing mound. The oldest monument with MBA burials was Barrow 3, in which the dead were buried in a two-stage sequence before and after the mid-2nd millennium BC. The youngest dated grave was Burial 1 in Barrow 1, comprising a collective burial that was interred between 1400 and 1200 BC. The additional analyses of carbon and nitrogen isotopes show significant differences in the diet of epi-CWC individuals buried in Barrow 2 from the individuals representing the KC.

Preparation of bones for radiocarbon (14C) dating is still quite a challenge for researchers. The methods are being tested and improved, to increase reliability of dating results and to verify the previous ones. In this work, a set of gelatine samples, extracted from Cervus elaphus and Cervus canadensis bones from various sites in Europe and a set of human bones from archaeological sites in Poland were subjected to retreatment using ultrafiltration in Gliwice Radiocarbon Laboratory. The tested samples represent a wide range of ages, from older than 40,000 14C years BP to modern. The prepared material was subjected to the measurement of C/N atomic ratios and 14C dating using the accelerator mass spectrometry (AMS) technique. Also, the stable isotopes (δ13C and δ15N) values were determined. In a few cases ultrafiltration allows to improve gelatine quality for long-stored samples, by increasing the %C and %N as well as decreasing C/Nat ratios. Nevertheless, this effect was not observed for majority of the samples. Remeasurements of long-term stored samples give mostly the same 14C ages for ultrafiltered ones and for those without ultrafiltration.

Five sites in present-day New York have played important roles in archaeological narratives surrounding the development of settled village life in northeastern North America. Excavated in the mid-twentieth century, the Roundtop, Maxon-Derby, Sackett or Canandaigua, Bates, and Kelso sites include evidence related to the transition from semisedentary settlement-subsistence patterns during the twelfth through fourteenth centuries AD to those associated with fifteenth century and later settled Iroquoian villagers. Radiocarbon dates for each site were obtained early in the development of the method and again following the transition to AMS dating. Here, we present new or recently-published dates for these sites, combined with reliable existing dates in Bayesian models, including in some cases short tree-ring sequenced wiggle-matches on wood charcoal. Our results clarify the timing of each site’s occupation(s), revealing both continuity and discontinuity in the development of longhouse dwellings, sedentism, and the repeated re-use of some site locations over hundreds of years.

Khirbet Al-Sheikh Humaid is found 615 m above sea level in the central highlands of Palestine, northwest of the city of Nablus. During rescue excavations carried out at the site, part of a male human skull with a tooth attached was discovered. Accelerator mass spectrometry radiocarbon (AMS 14C) dating and stable isotope analysis were performed on the tooth at the Hertelendi Laboratory in Debrecen, Hungary. Dating revealed the individual had lived in the time frame 900–1030 AD, which is within the Abbasid period (750–1258 AD). Dietary analysis gave information on the daily life of the inhabitants of the settlement, showing local agriculture provided a diet of legumes and vegetables.

Skin-based samples (leather, skin, and parchment) in archaeological, historic and museum settings are among the most challenging materials to radiocarbon (14C) date in terms of removing exogenous carbon sources—comparable to bone collagen in many respects but with much less empirical study to guide pretreatment approaches. In the case of leather, the 14C content of materials used in manufacturing the leather can vary greatly. The presence of leather manufacturing chemicals before pretreatment and their absence afterward is difficult to demonstrate, and the accuracy of dates depends upon isolating the original animal proteins and removing exogenous carbon. Parchments differ in production technique from leather but include similar unknowns. It is not clear that lessons learned in the treatment of one are always salient for treating the other. We measured the 14C content of variously pretreated leather, parchment, skin samples, and extracts, producing apparent ages that varied by hundreds or occasionally thousands of years depending upon sample pretreatment. Fourier Transform Infrared Spectroscopy (FTIR) and C:N ratios provided insight into the chemical composition of carbon reservoirs contributing to age differences. The results of these analyses demonstrated that XAD column chromatography resulted in the most accurate 14C dates for leather and samples of unknown tannage, and FTIR allowed for the detection of contamination that might have otherwise been overlooked.

In-situ cosmogenic 10Be (and 26Al) concentrations in alluvial sediments provide a spatially averaged signal of the erosion rate of the catchment area. Catchmentwide erosion rates reflect the production rate of the entire basin, and their calculation requires knowledge of the complete production rate model. Available calculators determine production rates on a pixel-based approach and achieve computational efficiency by relying on a scaling method that ignores geomagnetic field strength variations. Here we introduce a new python-based tool that determines erosion rates based on the hypsometry of the catchment. The method relies on the fact that production rates are much more sensitive to changes in elevation than latitude. Our tool has two main advantages: (1) computation time is short (<30 seconds) and independent of the scaling method; there is no need to neglect magnetic field variations, and (2) because production rate scaling is performed by a widely used online calculator, the results are fully comparable to exposure ages or point-based erosion rates determined with the same calculator; future updates to production rate scaling are immediately effective for catchmentwide erosion rate calculation. We demonstrate in two case studies that (1) for similar scaling methods, our calculator reproduces pixel-based results within a few percent, and (2) erosion rates determined with different scaling methods may differ by >20%, differences can vary systematically with erosion rate, and using a time-constant scaling method may result in a bias in the interpretation of catchmentwide erosion rates.

This commentary aims at raising awareness and fostering a discussion on the need of a new approach to the radiocarbon (14C) dating of historic mortars. Over the last decades, important advancements have been made in the application of the 14C dating methods to lime mortar samples, including the use of lime lumps instead of generic pieces of mortar. However, a relevant number of results in disagreement with the chronological framework of the related archaeological cases are published every year without a clear understanding of the reasons for such results. This suggests that further developments to the methodology are needed. The commentary argues that to further develop this particular application of the 14C dating method, a new, more holistic approach is needed that moves away from the very “applied” approach that dominated the last decades and focuses more on the causes of contamination and the mechanism of the reactions involved. Two actions are suggested that can immediately improve our ability to critically assess the results obtained: the publication of a chemical and mineralogical characterization of the binding fraction for the dated mortars, and the publication of sampling depth for each dated sample.

Nowadays, most radiocarbon (14C) laboratories can reliably avoid and remove any possible sample contamination during the pretreatment of organic samples (e.g., bones, charcoal, or trees) thanks to a series of methods commonly used by the radiocarbon community. However, what about the final step, the storage of graphite? Rarely do the laboratories produce their graphite and ship it as pressed targets to accelerator mass spectrometry (AMS) facilities for measurement. Pressed graphite in aluminum targets are vulnerable to contamination, and during shipment or storage, exogenous carbon can be introduced again. Here we report a test on various archaeological sample materials from different environments and different periods (from the past three millennia to the Middle Paleolithic period). We transformed them into graphite, pressed the graphite into targets and sent them to two different AMS laboratories to be dated. We observe that packing details of the targets, extended shipment and storage time may lead to contamination which can be avoided by appropriate packaging in tight metal cans and sealed in vacuum bags. Close cooperation and coordination between our chemistry laboratory and the AMS facilities, high standards in contamination removal, and efficient measurement planning enabled us to obtain reliable 14C ages within a short time.

The Lamoka Lake and Scaccia sites in present-day New York have played important roles in the development of archaeology in New York, and in the case of Lamoka Lake, in eastern North America. Lamoka Lake is the type site for the “Archaic” period in eastern North American culture history and the “Late Archaic” “Lamoka phase” in New York culture history. The Scaccia site is the largest “Early Woodland” “Meadowood phase” site in New York and has the earliest evidence for pottery and agriculture crop use in the state. Lamoka Lake has been dated to 2500 BC based on a series of solid carbon and gas-proportional counting radiometric dates on bulk wood charcoal obtained in the 1950s and 1960s. Scaccia has been dated to 870 BC based on a single uncalibrated radiometric date obtained on bulk charcoal in the early 1970s. As a result, the ages of these important sites need to be refined. New AMS dates and Bayesian analyses presented here place Lamoka Lake at 2962–2902 BC (68.3% highest posterior density [hpd])) and Scaccia at 1049–838 BC (68.3% hpd).

The lack of systematic chronologies is a key problem for the archaeological sites of Altai and adjacent territories during the Great Migration Period. Here we present an attempt to establish the chronology of the Bulan-Koby culture objects of the Karban-I necropolis by correlation of accelerator mass spectrometry radiocarbon (AMS 14C) data from human remains with data from archaeological dating methods. This is the first application of such a combined targeted 14C and archaeological approach to the chronology of the Great Migration Period materials of northern Altai, and in particular the Bulan-Koby culture. Systematic analysis of the mutual occurrence of dated types of certain grave goods and 14C dating of a series of samples supports a predominant period of use for the site that spans the 2nd–3rd c. AD, which corresponds to the early Xianbei period. This study demonstrates strong agreement between the indicators obtained by archaeological and radiocarbon methods, suggesting chronological consistency of the necropolis which functioned at the beginning of the Great Migration Period. The very combination of the two techniques will allow more precise and detailed chronologies for other archaeological complexes of Altai and adjacent territories from the first centuries of the 1st mil. AD, which is the basis of historical reconstructions.

Little is known about the early history of the chicken (Gallus gallus domesticus), including the timing and circumstances of its introduction into new cultural environments. To evaluate its spatio-temporal spread across Eurasia and north-west Africa, the authors radiocarbon dated 23 chicken bones from presumed early contexts. Three-quarters returned dates later than those suggested by stratigraphy, indicating the importance of direct dating. The results indicate that chickens did not arrive in Europe until the first millennium BC. Moreover, a consistent time-lag between the introduction of chickens and their consumption by humans suggests that these animals were initially regarded as exotica and only several centuries later recognised as a source of ‘food’.

This article presents current research on cooking stone pits in northern Germany and southern Scandinavia and examines their function and interpretation. It focuses on recent findings at the site of Mang de Bargen in northern Germany, which contained pit arrangements in various configurations, including a new circular one. The latest 14C dates from Mang de Bargen suggest that the circular formations constitute the earliest evidence of cooking stone pits known so far. A supra-regional comparison, concentrating on the distribution and dating of cooking stone pits in northern Europe, and an analysis of their content, arrangement, and topographic location allows the author to propose how they may have been used.

Bubiyan Island, presently a vast sabkha and salt flat in the westernmost part of the Shatt Al-Arab delta, originated ca. 4000 cal yr BP as prodelta deposits from a paleochannel of the Euphrates River that flowed into a shallow sea. Southeastern Bubiyan Island first surfaced when spits and barrier islands formed on a 1–2 m forebulge caused by heavy sediment load to the northwest; the spits and barriers delineated an incipient shoreline and sheltered a shallow lagoon. Progradation of southeastern Bubiyan Island began when the spits and barriers were gradually stranded as beach ridges during minor sea-level fluctuations and continued marginal uplift. AMS dating of the beach ridges, which are ~1–5 km from the present shoreline, implies that Late Holocene relative sea level fell in three phases: ca. 3700–3400 cal yr BP, ca. 2600–1000 cal yr BP, and ca. 600–500 cal yr BP. Prior to each phase, relative sea level apparently stabilized to near stillstands, allowing spits and barriers to accrete. Torpedo-jar pottery sherds scattered on some of the most prominent beach ridges indicate Sasanian (AD ca. 300–650; 1650–1300 cal yr BP) to early Islamic (AD ca. 650–800; 1300–1150 cal yr BP) periods of human presence, concurrent with the Second phase of beach-ridge formation.

The Meadowcroft Rockshelter in southwestern Pennsylvania is best known for its pre-Clovis occupation. Potentially important for later times is the recovery of maize macrobotanical remains from higher strata dating as early as the 4th century BC based on radiometric radiocarbon (14C) dates on wood charcoal. These remains have been considered to be potentially as old as the earliest microbotanical evidence for maize in Michigan, New York and Québec recovered from directly dated charred cooking residues adhering to pottery. The results of accelerator mass spectrometry (AMS) dating 17 samples from maize specimens from all Meadowcroft strata producing maize, indicate that the specimens originated from historical use of the shelter, most likely after AD 1800. These results further emphasize the need to obtain direct dates on maize macrobotanical remains recovered from early contexts prior to the development and common use of AMS dating.

Wally Broecker’s puzzles required radiocarbon dating in order to solve them.

This study obtained calendar dates by radiocarbon accelerator mass spectrometry (14C AMS) dating sequential tree-rings of wooden support posts from the buried remains of traditional Kitkahahki Pawnee earthlodges preserved at an archaeological site on the Central Great Plains, USA. The tree-ring segments from the site were dendrochronologically analyzed prior to this study, but the cross-matched site chronology could not be definitively cross-dated and was thus “floating” in time. Our study represents the first floating tree-ring chronology from the Great Plains to be anchored in time by means of independent radiocarbon analysis. Three specimens were analyzed and dated to 1724–1774 CE (82.0% probability), 1774–1794 CE (95.4% probability), and 1800–1820 CE (95.4% probability). These dates correspond to the hypothetical timing of Kitkahahki ethnogensis, the main phase of village growth in the area, and a later reoccupation during a turbulent period in regional history. The results of this study conform to a scenario in which chaotic social conditions correspond to an increase in residential mobility between the core of Pawnee territory and a southern frontier in the Republican River valley.

The main goal of our research project was to date the Early and Middle Copper Age (4500/4450–3800 cal BC) of the Great Hungarian Plain more precisely. In our project, we took samples for accelerator mass spectrometry (AMS) dating from both settlement features and burials, and the data were analyzed using Bayesian modeling. We examined the Early and Middle Copper Age finds of the Great Hungarian Plain on several levels (site, microregional, and regional levels) using a bottom-up approach. The AMS measurements were supplemented by statistics-based pottery analysis in order to make our understanding of the relationship between the Tiszapolgár and Bodrogkeresztúr cultures more detailed. As a result, we can see a significant, 130 (68.2%) 230 years overlap between the two types of find assemblages, which contradicts to the earlier accepted chronological sequences created by the traditional culture-historical approach. According to the stylistic analyzes, the two ceramic styles are not clearly distinguishable.

We present a new biennial record of radiocarbon (14C) measured in Danish oak. The new record covers the years 1251–1378 CE, thereby spanning the Grand Solar Minimum known as the Wolf Minimum. Two oak samples from every other year were measured at the AMS facility at Aarhus University (Denmark), resulting in an average precision of 1.4‰ for the record. Spectral analysis of the new record revealed two peaks at 27 and 9.1 years, which could indicate the Hale cycle was lengthened and the Schwabe cycle shortened during the Wolf Minimum, but it is also possible that the amplitude of the Schwabe cycle was too small to be accurately identified with the acquired precision of this record. The record was bandpass filtered to investigate the variability of the amplitude in different bands, which showed a dampening of the amplitude during the second half of the Wolf Minimum in bands centered on the Schwabe and the Hale cycle, respectively. A reconstruction of the solar modulation function, Φ, also showed a periodicity of ca. 9 years, and indicated that the Wolf Minimum was preceeded by one cycle of decreased solar activity.

We here present a comparison of methods for the pretreatment of a batch of tree rings for high-precision measurement of radiocarbon at the Aarhus AMS Centre (AARAMS), Aarhus University, Denmark. The aim was to develop an efficient and high-throughput method able to pretreat ca. 50 samples at a time. We tested two methods for extracting α-cellulose from wood to find the most optimal for our use. One method used acetic acid, the other used HCl acid for the delignification. The testing was conducted on background 14C samples, in order to assess the effect of the different pretreatment methods on low-activity samples. Furthermore, the extracted wood and cellulose fractions were analyzed using Fourier transform infrared (FTIR) spectroscopy, which showed a successful extraction of α-cellulose from the samples. Cellulose samples were pretreated at AARAMS, and the graphitization and radiocarbon analysis of these samples were done at both AARAMS and the radiocarbon dating laboratory at Lund University to compare the graphitization and AMS machine performance. No significant offset was found between the two sets of measurements. Based on these tests, the pretreatment of tree rings for high-precision radiocarbon analysis at AARAMS will henceforth use HCI for the delignification.