We present a radiocarbon (14C) dataset of tropospheric air CO2, forest soil air CO2, and soil CO2 emissions over the course of one growing season in a Scots pine forest in southern Finland. The CO2 collection for 14C accelerator mass spectrometry (AMS) analysis was done with a portable, suitcase-sized system, using molecular sieve cartridges to selectively trap CO2. The piloting measurements aimed to quantify the spatial, seasonal and diurnal changes in the 14C content of CO2 in a northern forest site. The atmospheric samples collected above the canopy showed a large seasonal variation and an 11‰ difference between day and nighttime profiles in August. The higher Δ14C values during night are partly explained by a higher contribution of 14C-elevated soil CO2, accumulating in the nocturnal boundary layer when vertical mixing is weak. We observed significant seasonal trends in Δ14C-CO2 at different soil depths that reflected changes in the shares of autotrophic and heterotrophic respiration. Also the observed diurnal variation in the Δ14C values in soil CO2 highlighted the changes in the origin of CO2, with root activity decreasing more for the night than decomposition.

There is increasing awareness of the need to correct for freshwater as well as marine reservoir effects when undertaking radiocarbon (14C) dating of human remains. Here, we explore the use of stable hydrogen isotopes (δ2H), alongside the more commonly used stable carbon (δ13C) and nitrogen isotopes (δ15N), for correcting 14C freshwater reservoir offsets in 10 paired human-faunal dates from graves at the prehistoric cemetery of Shamanka II, Lake Baikal, southern Siberia. Excluding one individual showing no offset, the average human-faunal offset was 515±175 14C yr. Linear regression models demonstrate a strong positive correlation between δ15N and δ2H ratios, supporting the use of δ2H as a proxy for trophic level. Both isotopes show moderate but significant correlations (r2 ~ 0.45, p < 0.05) with 14C offsets (while δ13C on its own does not), though δ2H performs marginally better. A regression model using all three stable isotopes to predict 14C offsets accounts for approximately 65% of the variation in the latter (r2=0.651, p=0.025), with both δ13C and δ2H, but not δ15N, contributing significantly. The results suggest that δ2H may be a useful proxy for freshwater reservoir corrections, though further work is needed.

On the island of Lolland, southeast Denmark, an area of almost 300 ha is currently under archaeological investigation prior to the planned construction of a tunnel between Denmark and Germany under the Femern belt. The area investigated in the context of the “Femern project” includes a former fjord or lagoon, which was used both as an economic resource and as background for ritual activities in the Neolithic. The wetland conditions give excellent preservation conditions for organic material. A yet unsolved issue, however, is the question of reservoir effects. The local reservoir effect needs to be known for accurate radiocarbon (14C) dating of samples with possible aquatic carbon sources, such as human bones or food residues on pottery. Therefore, this paper attempts to calculate the local reservoir effect for the study area. I will discuss the possibilities and limitations when analyzing 14C dates from a rescue excavation. When applying the estimated reservoir corrections to a hoard of jaws and other bones, an interesting change in ritual activity at ca. 4000 cal BC can be observed. Furthermore, I examined 14C dates on bulk organic sediment and will discuss their implications for building chronologies and for reconstructing the environment of the Stone Age fjord. Finally, I will discuss the pitfalls and uncertainties associated with 14C dates for sea level reconstruction.

A 22 m sediment core was collected from the unsaturated zone (USZ) in the dunes south of Ashdod, Israel, in a low rainfall year, following an even lower-rainfall year. The mineralogy of was quartz with some clay and carbonate. The local climate is semi-arid. The roots of the sparse vegetation can reach ~8 m. The porosity was ~40–55%. The DIC ranged from 2 to 13 mmole C/L. Large variability is noted in the soil moisture, with a maximum at the high clay region at ~8 m. Oxygen isotopes enter the USZ with rain falling on the surface. There is 18O enrichment in the top of the section due to evaporation during the summer. Below this depth δ18O values of ~ –5‰ prevail as in the local aquifer. CO2 and the carbon isotopes enter the USZ laterally by exhalation from roots. The δ13C varies from –5‰ to –23‰, representing stages in carbon isotopic fractionation: CO2gas becomes dissolved CO2aqueous which then forms carbonic acid and HCO3– . The high δ13C, Δ14C, and DIC are found at the 8 m depth. These values along with high humidity are replicated at ~22m depth. They most probably represent recharge water from the previous rainy season at 8 m depth subsequently pushed down 12.8±0.8 m during the last winter.

Secondary carbonate deposits (similar to speleothems) in urban undergrounds, have been recently highlighted as powerful archives for reconstruction of the historical anthropogenic imprint on the environment. The precise chronology of these secondary carbonate deposits is a key issue for the accurate time reconstruction of environmental conditions. We present three 14C data sets for urban speleothem-like deposits that developed in contrasted man made environments. The first one was sampled in an underground technical gallery of the Palace of Versailles (France), and the other two in a manhole (Saint-Martin spring) of a historical underground aqueduct in Paris (France). The comparison of these records with the bomb peak and relative chronology (laminae counting) allowed us to identify: i) fast carbon transfer from the atmosphere to the urban underground; ii) a high proportion of dead carbon and a high damping effect in relation to possible old carbon stored within urban soils and/or the influence of local fossil carbon burning. This study also shows that the lamination of these deposits is bi-annual in these highly urbanized sites.

Tollund Man is one of the most famous Iron Age bog bodies due to his well-preserved head. Since he was unearthed in 1950 in Bjældskovdal, Denmark, he has been subjected to several scientific investigations, but until now no attempts to reconstruct his general diet through isotope analyses have been conducted. Furthermore, previous radiocarbon (14C) analyses have only been able to date him broadly to the 3rd–4th century BC. In this study, stable isotope measurements (δ13C, δ15N) on bone collagen from Tollund Man’s femur and rib showed that the diet of Tollund Man was terrestrial-based and that the crops he ate probably were grown on manured fields. Accelerator mass spectrometry (AMS) 14C dates were obtained on both the <30kDa and >30kDa fractions of ultrafiltered collagen. Results showed that the ultrafiltration removed contamination from older substances from the burial environment. The femur was dated to 2330±23 BP, the rib to 2322±30 BP. These dates statistically agree with a previously published AMS 14C age on skin. By combining the new dates with the previous date of his skin it was possible to narrow down the age of Tollund Man to the period 405–380 cal BC (95.4% confidence interval).

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.

A preliminary evaluation of gaseous radiocarbon (14C) behavior under geological repository conditions for Italian radioactive high level waste-long-lived and intermediate level waste disposal has been performed. Although in Italy there is still no defined project for a geological disposal facility, current work may support future safety assessment studies for a hypothetical future repository in deep salt rock. In the Italian context of radioactive waste, the percentage of 14C bearing waste to be disposed in a possible geological repository is low; irradiated graphite is the most important radiological source. Data about the radiological inventory has been collected to simulate production and migration of gaseous 14C in a hypothetical geological repository. Three different conceptual models have been developed and simulated. The first model has considered a preliminary evaluation of the radiological impact referred to the whole inventory; the second and third model have evaluated the impact only due to the irradiated graphite. A preliminary sensitivity analysis has been carried out, highlighting the importance of geometry and of distribution coefficients (Kd) in materials used to seal the disposal underground facility. Results show the possibility to correlate the Kd values, the volume and the location of the sealing materials to the amount of 14C migrating toward the surface.

We report radiocarbon (14C) dates on bone samples of Ursus ladinicus, a small cave bear species well adapted to a life in the mountains, whose remains were found in Conturines Cave. Located at 2775 m asl in the Dolomites of northern Italy, this cave is by far the highest known cave bear site worldwide. Eleven 14C dates obtained by the Belfast and Oxford laboratories on samples showing good collagen preservation yielded consistent ages in excess of 46–50 ka BP. These results show that contrary to the previously held view these cave bear remains are older than Marine Isotope Stage 3, and likely date from a warm climate period with a high treeline, possibly the Last Interglacial.

Multiple burial in medieval burial grounds are often interpreted as a result of disease, but it is difficult to test such hypotheses, as most acute infectious diseases leave no visible evidence on skeletal material. Scientific dating can potentially associate multiple burials with historically documented epidemics, but the precision required to exclude alternative explanations would normally be attainable only by dendrochronology. Here, we argue that by combining archaeological, osteological and paleodiet research in a Bayesian framework, we can exploit differences in dietary reservoir effects to refine the dates of multiple burials, and potentially date such events to within a range of <20 years. We present new radiocarbon (14C) and stable isotope (δ13C, δ15N) results from a medieval multiple grave at St Alban’s Odense, on the island of Funen in central Denmark. We show the ca. 150-yr spread in 14C ages of the five juveniles is compatible with differences in the amount of fish they consumed. Our chronological model, which combines marine reservoir effect correction with calendar age offsets based on osteological evidence, dates the multiple burial to cal AD 1425–1445 (95% probability), an interval in which two plague epidemics took place in Denmark.

The potential 14C (carbon-14, radiocarbon) flux from disposal of 14C containing waste into air is compared with the natural 14C emanation rate from soil in order to put the 14C hazard potential from disposal of this waste in perspective with the 14C exposure from cosmogenic origin. Chemical corrosion of neutron irradiated metals, steel and Zircaloy, is bounded by diffusion of water through a thermodynamically stable metal-oxide layer and dissolution of this metal-oxide in a nuclear plant. Many countries process radioactive waste for disposal using cementitious materials, an acknowledged end-point management technique for this waste. The metal-oxides are also stable when these waste forms are embedded in cementitious materials. The 14C release rate from this Zircaloy at these alkaline and reducing conditions is comparable to the natural 14C emanation rate from soil into air. Neutron irradiated graphite and spent ion exchange resins are chemically inert and therefore other release mechanisms need to be assumed. Radiolytic corrosion is used to determine the 14C release rate from this graphite. Moreover, ion exchange—with ingressing anionic species that have a higher affinity than contained anionic 14C—is proposed as a release mechanism for these resins.

This article presents the first radiocarbon (14C) results from the Late Bronze Age levels of Tel Azekah (Israel). The results testify to the long and prosperous occupation of the site during this period, commencing at least in LB IIA and ending with a severe destruction at the close of LB III. In the extra-mural quarter (Area S2), a pre-monumental building phase (S2-6) dates to the 14th or early 13th century BCE. Two sub-phases of a public building constructed above this yielded dates in the second half of the 13th century and first two-thirds of the 12th century BCE, suggesting that occupation persisted through the “Crisis Years” of the eastern Mediterranean region. On the top of the mound, in Area T2, the destruction of the final LB III level (T2-3) most likely occurred near the end of the 12th century BCE. The preliminary Azekah results are in good agreement with existing data from Lachish and Megiddo, but seem at odds with results from nearby Tel es-Safi/Gath.

We report new accelerator mass spectrometry radiocarbon (AMS 14C) dates of bones from humans, animals, and fish from grave 12 of the Lebyazhinka V Eneolithic burial ground in the middle Volga River region, Russia. Earlier conventional dates established a chronology. This has to be adjusted by new insights: the date has to be corrected for reservoir effects. For this purpose we redated bone from a human, and for herbivore and freshwater fauna from the same context, and included measurements of the stable isotopes δ13C and δ15N. The reservoir offset for the human appears to be about 700 14C yr.

A robust marine radiocarbon (14C) reservoir correction (ΔR) is essential for calibrating 14C dates of marine mollusks and fish bones routinely found in archaeological sites as discarded food remains and bones of terrestrial animals (including humans) with an appreciable marine diet. New ΔR values are reported for the atoll archipelago of the Marshall Islands, eastern Micronesia. Atolls consist of biogenetic material—mostly coral and foraminifera—that can be directly dated for establishing sequences of atoll emergence and islet development. After sectioning and examination using scanning electron microscopy (SEM) to screen for sample diagenesis, 6 pristine branch coral samples were selected from the modern oceanside beach, 3 archaeological sites, and islet developmental facies from Ebon Atoll (4º34′N, 168º41′E). Each sample was analyzed by U-series and accelerator mass spectrometry (AMS) 14C showing no substantial temporal ΔR variations and yielding a weighted mean ΔR of 41±42 yr1 spanning ~500 yr before earliest human colonization (the period when islets first became habitable) through the entire 2000-yr occupation sequence. Reliable published ΔR values for Micronesia and Δ14C data for Palmyra Island, together with our results for Ebon Atoll, indicate that the Pacific North Equatorial Counter Current is almost stable for the past 2500 yr.

Human burials from the cemetery at the Rounala church, northern Sweden, were radiocarbon (14C) dated to shed light on the use of the cemetery. Carbon, nitrogen and sulfur stable isotope analysis of bone collagen from 19 distinct individuals indicated that these individuals had a mixed diet consisting of freshwater, marine and terrestrial resources. Dietary modeling using FRUITS was employed to calculate the contributions of the different resources for each individual. These data were then used to calculate individual ΔR values, taking into account freshwater and multiple marine reservoir effects, the latter caused by Baltic and Atlantic marine dietary inputs, respectively. 14C dating of tissues from modern freshwater fish species demonstrate a lack of a freshwater reservoir effect in the area. Two OxCal models were used to provide endpoint age estimates. The calibrated data suggest that the site’s cemetery was most likely in use already from the 14th century, and perhaps until at least the late 18th century.

Radiocarbon (14C) in dissolved inorganic carbon (DIC) was measured for water samples collected from six deep stations in the Kuroshio Extension (KE) region in the northwestern North Pacific in April–May 2015. Vertical profiles of Δ14C-DIC indicate that bomb-produced 14C was present from the surface to ~1500 m water depth. Large variations in Δ14C-DIC values (300‰) were observed at 500 m water depth among the stations and the differences were likely controlled by transport and mixing dynamics of different water masses in the region. The major Pacific western boundary currents, such as Kuroshio and Oyashio and regional mesoscale eddies, could play important roles affecting the observed Δ14C-DIC variability. The depth profiles of both Δ14C-DIC and DIC concentrations can be predicted by the solution mixing model and can be used as conservative tracers of water mass movement and water parcel homogenization in the ocean.

Radiocarbon (14C) activity in groundwater can be used to determine subsurface residence time up to ∼40 kyr, providing crucial information on dynamic properties of groundwater and on paleoclimate. However, commonly applied sampling methods for dissolved inorganic carbon (DIC-14C) are prone to low level of modern atmospheric contamination, resulting in underestimation of groundwater ages that cluster around 30–40 kyr. We extract CO2 gas from groundwater using a device originally developed for studies of noble gas radionuclides. Carbon is collected in the gas phase, eliminating the possibility of fostering microbial activities and aqueous chemical reactions during sample storage. This method collects CO2-14C and radiokrypton (81Kr and 85Kr) samples simultaneously. The presence of any shorter-lived 85Kr is used to evaluate the degree of atmospheric contamination during sampling or mixing of young groundwater. Most groundwater samples showed lower CO2-14C activities than those of DIC-14C, presumably due to the absence of atmospheric contamination. Samples with 81Kr age exceeding 150 kyr have no detectable CO2-14C except where mixing sources of young groundwater is suspected. These field data serve as confirmations for the reliability of the newly presented sample collection and CO2-14C method, and for the outstanding roles of radiokrypton isotopes in characterizing old groundwater.