As part of the study of the early medieval cemetery at Broechem (Belgium), human bones from 32 cremation graves have been dated through radiocarbon (14C) analysis. It was noted that many of the dates were not in accordance with the chronological ranges provided by the characteristics of the cultural artifacts deposited in the graves. In fact, the human bones were “older” than the artifacts. Subsequently, a number of animal bones (in all cases from domestic pigs) was radiocarbon dated, yielding dates that were more consistent with the information from the cultural artifacts than the human bones. The dates obtained on human and pig bones from the same grave often differed around 100 radiocarbon years. This paper tries to find an explanation for the pattern observed, concentrating on two hypotheses: aquatic reservoir versus old wood effects. The evaluation takes into account additional radiocarbon dates derived from charcoal fragments of the funeral pyre, from both short-lived and long-lived taxa. A conclusive explanation for the anomalous radiocarbon dates could not be reached but clear suggestions can be put forward for future experimental work that will without doubt shed more light upon the interpretational problems raised.

Micropaleontological and geochemical data were applied to sediments from southeastern Brazil to study the hydrodynamics associated with the Holocene sea level rise. Sediment cores were taken around Vitória Bay, examined for dinoflagellate cysts and subjected to isotopic analysis. The cyst assemblage mainly dominated by autotrophic species most notably O. centrocarpum, L. machaerophorum and T. vancampoae. The influence of the marine transgression and subsequent regression observed during the Holocene along the coast of Brazil could have initially favored the establishment of an oligotrophic and higher energy environment. The inflow of continental water from tributaries combined with a higher inflow of saline water into the estuarine system could have favored the establishment and subsequent deposition of the dinocysts.

Radiocarbon (14C) can be used to build absolute chronologies and reconstruct ocean ventilation over the last 40 ka. Sample size requirements have restricted 14C measurements in marine cores with low foraminifer content, impeding 14C-based studies focused on abrupt climate events. Recent developments have demonstrated that small-sized foraminifer samples can now be dated using a gas introduction system at the cost of a small decrease in precision. We explore the potential of gas measurements on benthic and planktonic foraminifers from core SU90-08 (43°03′1″N, 30°02′5″W, 3080 m). Gas measurements are accurate, reproducible within 2σ uncertainty and comparable to graphite measurements. Both techniques yield negative 14C benthic-planktonic (B-P) age-offsets after Heinrich event 1. We argue that negative B-P ages result from bioturbation and changes in foraminifer abundances, with the chance of negative B-P especially increased when the 14C age gradient between the deep and surface waters is decreased. Small-sized 14C measurements seem to capture the variance of the foraminifera age distribution, revealing the active mixing in those archives. Sediment deposition and mixing effects possibly pose a greater obstacle for past 14C-based dating and ocean ventilation reconstructions than the measurement precision itself, particularly in relatively low sedimentation rate settings.

Identifying and tackling recrystallization is a critical factor in the reliable radiocarbon (14C) dating of carbonates, since exogenous carbon can be incorporated and thus mask the real age of the samples. Vermetids are among the most important bioindicators used for paleo sea-level reconstruction, and the accuracy of their chronology can significantly impact sea-level curves. Age differences larger than 1 14C kyr before and after acid etching, combined with X-ray diffraction (XRD) analysis that indicates a significant amount of calcite still remains in the shell, led us to apply the previously developed carbonate density separation protocol (CarDS). Using a solution of sodium polytungstate, with density of 2.80 g/cm3, we successfully separated different carbonate fractions for a set of 10 vermetid samples from the coast of Rio de Janeiro, southeast of Brazil. Each separation was verified by XRD analysis and the 14C concentrations of different fractions were compared. The results show that the calcite fraction in the studied vermetid samples varied from 12 to 63% and aragonite fraction ages are up to 2 14C kyr older than the raw samples, thus confirming the efficacy of CarDS in removing young carbonates and the importance of density separation to vermetids prior to accelerator mass spectrometry (AMS) dating.

Acid-alkali-acid (AAA) pretreatment is widely used to clean terrestrial plant macrofossil samples for radiocarbon (14C) dating. There is wide variation amongst laboratories in the AAA method details and less rigorous AAA pretreatment is often used on fragile or small samples. Yet there is little evidence as to the efficacy of the different methods and whether the use of less rigorous methods is justified. We investigated four variations of AAA pretreatment: acid only (no alkali wash); room temperature AAA; “standard” AAA at 85°C; and “aggressive” AAA at 85°C with alkali washes repeated until no discoloration was detected. We tested six different terrestrial macrofossils from four different locations and ranging in age from mid-Holocene to the Last Glacial Maximum. Our results demonstrate that while acid only is not always sufficient to remove young material, there is no difference in 14C age of samples pretreated by any of the AAA variants. We also observed mass loss of 85–90% in the standard and aggressive AAA pretreatments, and much more modest mass loss in the room temperature AAA pretreatment. Therefore, we conclude that room temperature AAA pretreatment is optimal to remove contaminating material from fragile terrestrial macrofossils while retaining the majority of the authentic sample material.

The emergence of hilltop settlements presents a pattern of the first enclosed sites that reflect economic development in several regions within the Southeastern Baltic Bronze Age. This novelty reflects increasing social complexity, differentiating economic relations, as well as rising tension in the region. The phenomenon has received a great deal of interpretation, but chronological problems still remain understudied. Researchers tend to seek the start of hilltop settling practice from early to late II millennium BC. This paper presents 14C dates from 7 sites in inland Lithuania, where hitherto no absolute dates were published. The majority of absolute dates has been calibrated to the Hallstatt radiocarbon calibration plateau (ca. 800–400 cal BC) which is significantly later than previously presumed based on dates from Belarusian sites. However, several dates from previously dated hilltop settlements in the region predate the effect. These results indicate the start of hilltop settling practice around 11th–9th centuries cal BC. Review of new and previously published radiocarbon dates suggests a different internal development between SE Baltic coastal and inland regions, likely locating zones, where economic outside stimulus preconditioning emergence of hilltop settlements occurred earlier.

Experimental studies have shown that significant carbon exchange occurs between bone-apatite and the pyre atmosphere during cremation, which can cause a calendar date offset between the radiocarbon (14C) event and the date of cremation. There are limited empirical data available to assess the magnitude of such wood-age offsets, but the aim of this paper is to test if they can be modeled statistically. We present new 14C dates on modern bone cremated in realistic open-air experiments and on archaeological samples of cremated bone and associated organic material. Experimental results demonstrate a wide range of carbon exchange with a mean of 58.6 ± 14.8%. Archaeological results indicate that the wood-age offsets have an approximately exponential distribution. We test whether the default Charcoal Outlier_Model in OxCal v4.3, developed to reduce the impact of wood-age offsets in dates of charcoal, is appropriate for cremated bone, but find that it slightly underestimates apparent offsets. To counter the intrinsic age of both pyre fuel and unburned bio-apatite, we instead propose a bespoke Cremation Outlier_Model, which combines an exponential distribution of calendar age offsets with a minimum offset, and provides better estimates of the actual dates of cremations.

The Madaras profile found at the northernmost fringe of Bácska loess plateau is one of the thickest and best-developed last glacial loess sequences of Central Europe. The 10-m profile corresponds to a period between 29 and 12 b2k. To unravel feedback to small-scale centennial climatic fluctuations at our site, recorded in the Greenland ice and North Atlantic marine cores, construction of a reliable chronology is needed. Reliability is expressed in terms of best achievable chronological precision. Accuracy however is based on choosing the model best describing the sedimentological features of our profile. Five different age-depth models had constructed and compared relying on 15 14C dates using various statistical, probabilistic approaches to choose the model with the highest achievable precision. Accuracy was also evaluated using accumulation rates against stratigraphy. Models constructed using the computer program Bacon performed best in terms of achieving the best possible stratigraphic accuracy. Seven meters of the profile represents the period of the LGM. The average sedimentation time was 16.8 yr/cm with the highest confined to the period of the LGM. Calculated average sedimentation rates were 4 times higher than previously reported. The peak accumulation periods are dated to the nadir of the LGM.

The Gaspereau Lake Reservoir Site Complex in Nova Scotia, Canada, yielded a large ceramic assemblage that permitted the first fine-grained analysis of ceramic change in the region at the Middle–Late Woodland Transition from ca. 1550 BP to ca. 1150 BP. The aim of this study was to refine the standard regional chronology first proposed by researchers J B Petersen and D Sanger. To do this, ceramics were directly dated using accelerator mass spectrometry (AMS), and the assemblage was categorized and analyzed to identify clusters of attributes. Ten AMS dates were acquired on carbonized food residue on the interiors of pottery and yielded the largest continuous ceramic sequence in the Maritime Provinces of Canada. This sequence was used to infer a change in manufacturing practices between the Middle (2150–1300 BP) and Late (1300–500 BP) Woodland periods and to propose five new subperiods between 1650 BP and 950 BP. Increasing incidence of coil breaks and temper percentage from the Middle to the Late Woodland were found to be chronologically sensitive. The analysis showed that, at Gaspereau Lake, a gradual shift from finely decorated and manufactured pottery to expediently made pottery suggests that pottery was made in larger numbers to support large-scale gatherings.

Differential sources of sedimentary organic compounds in a volcanic region were revealed by determining radiocarbon content (Δ14C) of organic compounds in surface sediments from Lake Kawaguchi, at the northern foot of Mount Fuji, central Japan. The Δ14C values of C16 fatty acid (−124‰) and chlorophyll a (Chl a) (−133‰) were similar to the Δ14C of dissolved inorganic carbon (DIC) in surface water (−117‰), suggesting that a significant portion of these compounds originated from modern primary producers with a reservoir age of ~1000 years. On the other hand, a large offset between the Δ14C values of Chl a (−133‰) and those of 132, 173-cyclopheophorbide-a-enol (−169‰) and pheophytin a (−179‰) suggested contributions from older pigments. In addition, the Δ14C of long-chain (C24, C26, and C28) fatty acids (−183 to −75‰) showed a large offset from that of a plant leaf remain (0‰) within sediments, demonstrating that the long-chain fatty acids were affected by substantial contributions from pre-aged terrestrial materials. Overall, the sedimentary organic compounds gave 14C ages older than the plant leaf fragment within sediments; however, the similarity between Δ14C of the C16 fatty acid and DIC implies potential for applying compound-specific radiocarbon analysis as a dating tool in volcanic lake environments.

Laser ablation (LA) accelerator mass spectrometry (AMS) is a novel method for rapid online radiocarbon (14C) analysis of carbonates. The quasi-continuous 14C profiles obtained with this technique demand a customized data evaluation protocol to relate the acquired 14C data to the analyzed sample. We take into account the mixing effects due to the minimal counting (integration) time of the AMS, the finite width of the laser beam and the gas washout of the ablation volume. Thereby we mathematically describe our LA setup with a system function that acts on the produced CO/CO2 (COX) from the sample resulting in a mixing of the 14C profiles obtained by AMS analysis. Furthermore, we analyze the long-term target memory effect in the gas ion source and establish a routine for correction. The correction routine is tested with a stalagmite comprising a growth stop that is analyzed at different scanning velocities indicating that only the slow scanning velocity can provide the necessary resolution to determine the width of the growth stop of 365 μm.

Radiocarbon (14C) dating was performed on samples from the prehistoric settlement at Makriyalos, northern Greece, a “flat extended” (rather than tell) site. Two separate occupation phases, Makriyalos I and II, were clearly distinguished on different sides of a low hill and belonged to the Late Neolithic I and II periods, respectively. Individual phases related to the use of circuit ditches and borrow pits were also recognized and dated. Phase modeling was applied in order to establish the sequence and duration of use of different features. The earliest activity seems to be around 5450 BC, among the earliest dates in northern Greece for the beginning of the LN and perhaps reflecting some earlier activity. The transition from LNI to LNII occurred at around 4950 BC without discontinuity earlier than other sites in Macedonia but perhaps same time as Thessaly. Intermediate ditch cutting phases occurred at 5300 and 5050 BC. A cemetery in the area of the settlement, initially thought to relate to the LNII phase of the settlement, was shown to date in the EBA period (beginning of 3rd millennium BC).

In 1989 an ancient burial consisting of a skeleton and a few objects was discovered at the Monte dei Cappuccini Monastery, in Torino (Italy). Anthropological analysis of the skeleton revealed that it belonged to a young man, and the archaeometric characterization of the objects suggested that most of them are compatible with the Medieval period. As a proper archeological survey was not conducted at the time of the finding, due to the religious nature of the site, a high-precision radiocarbon (14C) dating has been performed. The samples were processed with three different methods: besides the ultrafiltration (UF) treatment, we applied the “collagen” (COL) and the Longin-base (LB) methods. While UF and COL treatments provided compatible results, LB method returned ages older with respect the UF one, with significant disagreements in some cases and this evidence is supported by several measurements on the same individual. Thanks to the reduction of the uncertainty with the high number of measured samples and the availability of historical evidence, the possible age of the burial has been limited to the time interval 1464–1515 cal AD.

In this paper we present data from the measurements of carbon isotopes (Δ14C and δ13C) from α-cellulose extracted from pine tree-rings. The samples were collected in four forests located in the most industrialized part of Poland, where coal mining and coal-based energy are an important branch of industry. The investigated period of time (1975–2012) covers the period of development in coal mining and other industry sectors. Stable isotope composition has been determined with using IRMS and radiocarbon concentration was determinate by AMS.

The early Holocene in North Africa remains a poorly known period, documented unequally by region. Eastern Algeria and Tunisia have the greatest number of deposits, but most were excavated decades ago without the controls and recording required for modern interpretation. The chronological framework is based on radiocarbon (14C) dates that are also old, for the most part. Recent work on Mesolithic lithic industries of Western Europe has enabled us to revive the hypothesis of the existence of contacts between the northern and southern shores of the western Mediterranean at least by the 6th millennium cal BC. A collective research program was conducted in 2016–2017 to test this hypothesis with a particular focus on documenting the technological traditions in the lithic industry and situating them precisely in time. We have 46 new radiocarbon dates that were recently carried out on previously excavated Algerian sites, some of which contain several levels, allowing the construction of Bayesian models. These new measures reinforce the hypothesis of contacts between Europe and Africa by demonstrating the contemporaneity of similar technological processes. Above all, they make it possible to accurately refine the chronology of the main cultural entities of the Maghreb at the beginning of the Holocene.