The CO2 absorption and liquid scintillation counting (LSC) are methods used in radioactivity monitoring programs of nuclear facilities for 14C measurements due to high number of samples and relatively high expected level of 14C concentration. The paper describes the chemical sample preparation applied to a quality control material (IAEA-C3 Cellulose), in order to evaluate the reproducibility of CO2 absorption method for this type of material. Consequently, in the experiments we used two home-made scintillation cocktails, containing two amines, 2-methoxyethylamine (MEA) and 3-methoxypropyl amine (MPA), which detained CO2 as carbamates. Due to the fact that the material used in the dedicated experiments is cellulose (contained in all vegetable materials), the method can be considered as appropriate for 14C determination from biological and vegetable materials.

We present a new low-cost, high-throughput method for converting many types of organic carbon samples into graphite for radiocarbon (14C) measurements by accelerator mass spectrometry (AMS). The method combines sample combustion and reduction to graphite into a single procedure. In the Single Step method, solid samples are placed directly into Pyrex containing zinc, titanium hydride and iron catalyst. The tube is evacuated, flame sealed, and placed in a muffle furnace for 7 hr. A variety of organic samples have been tested including oxalic acid, sucrose, wood, peat, collagen, humic acid, and contamination swipe samples. The method significantly reduces the time required to produce a graphite sample for 14C measurement, with analytical precision and accuracy approaching that of traditional two-step combustion and hydrogen reduction methods. The details and applicability of the method are presented.

Radiocarbon (14C) analysis of carbon dioxide (CO2) provides unique information on the age, turnover and source of this important greenhouse gas, raising the prospect of novel scientific investigations into a range of natural and anthropogenic processes. To achieve these measurements, cartridges containing zeolite molecular sieves are a reliable and convenient method for collecting CO2 samples. At the NERC Radiocarbon Facility (East Kilbride) we have been refining our molecular sieve methods for over twenty years to achieve high-quality, reproducible and precise measurements. At the same time, we have been developing novel field sampling methods to expand the possibilities in collecting gas from the atmosphere, soil respiration and aquatic environments. Here, we present our latest improvements to cartridge design and procedures. We provide the results of tests used to verify the methods using known 14C content standards, demonstrating reliability for sample volumes of 3 mL CO2 (STP; 1.6 mg C) collected in cartridges that had been prepared at least three months earlier. We also report the results of quality assurance standards processed over the last two years, with results for 22 out of 23 international 14C standards being within measurement uncertainty of consensus values. We describe our latest automated procedures for the preparation of cartridges prior to use.

In this paper, we present the first data from an alternative extraction method for atmospheric 14CO2 analysis, based on the direct trapping of whole air samples onto a molecular sieve zeolite (13X) trap, incorporated into a commercially available automated graphitization system. Results are presented for both inter-laboratory comparison samples and an in-house reference standard. The in-house reference was used to calculate the standard deviation of measurements (2.0‰). This newly developed method will facilitate faster sample processing and therefore lower cost per analysis, critical for scaling up such studies.

We studied a suitable procedure for preparing of water samples used in radiocarbon intercomparisons involving dissolved inorganic carbon (DIC). The water samples must have inter-batch consistency and stable 14C concentrations and no sterilizing agent (e.g., HgCl2) should be added, in order to avoid the production of hazardous material. Six water samples, containing widely different amounts and types of salts, DIC, and 14C concentrations (1–100 pMC), were prepared in order to assess the procedure. Sample consistency was investigated through δ13C and chemical compositions; their low variabilities indicate that our procedure can be applied to radiocarbon intercomparison. A specific sample preparation protocol was developed for this kind of applications.

The elk/moose (Alces alces) was an important resource for prehistoric societies. In prehistoric art, it is often depicted in connection with water. Biologists find that elk spend much time in water and consume considerable amounts of aquatic plants. As freshwater plants can have reservoir ages of hundreds or even thousands of years, there is a risk of a significant reservoir effect in elk bones and antler, and artifacts made of these materials. This pilot study followed several approaches to investigate the possibility of a freshwater reservoir effect in elk. I analyzed modern, historical and archaeological bones and antler from several sites across Eurasia. Skull bone and antler of the same individual were radiocarbon dated, as antler is formed in summer, when the proportion of aquatic diet is supposed to be highest. Age offsets measured in this study were zero to about 500 years. A difference between bone and antler could not be determined. The reservoir effect appears to be smaller than estimated from accounts of elk diet, even in regions where a substantial freshwater reservoir effect is expected. Therefore, the hypothesis of a large proportion of aquatic diet can be rejected for several of the individuals studied here.

The bomb-peak signal preserved in the Arches® cotton paper was used to detect art forgeries imitating the work of Chinese artist T’ang Haywen (1927–1991). The dating of seven legitimate T’ang Haywen art pieces showed that the timing of the paper production was consistent with the artist’s use of Arches® paper starting in the early 1980s. The measured F14C of the paper from the 14 suspected forged paintings shows that the support material was produced in the last decade (2008–2011), therefore the art pieces could not be genuine T’ang Haywen works.

Our ability to reliably use radiocarbon (14C) dates of mollusk shells to estimate calendar ages may depend on the feeding preference and habitat of a particular species and the geology of the region. Gastropods that feed by scraping are prone to incorporation of carbon from the substrate into their shells as evidenced by studies comparing the radiocarbon dates of shells and flesh from different species on different substrates (Dye 1994; Hogg et al. 1998). Limpet shells (Patella sp.) are commonly found in prehistoric midden deposits in the British Isles and elsewhere, however these shells have largely been avoided for radiocarbon dating in regions of limestone outcrops. Results from limpets (Patella vulgata) collected alive on limestone and volcanic substrates on the coasts of Ireland indicate that the shells were formed in equilibrium with the seawater, with no significant 14C offsets. Limpets collected from the east coast of Northern Ireland have elevated 14C due to the output of Sellafield nuclear fuel reprocessing plant. In all locations, the flesh was depleted in 14C compared to the shells. The results will have an important consequence for radiocarbon dating of midden deposits as well as the bone of humans and animals who fed on the limpets.

The trajectory of the Kuroshio, the western boundary current in the north Pacific, influences regional climate. It intrudes into the South China Sea (SCS) through the Luzon Strait, resulting in the exchange of water, nutrients, heat, and salt between the Pacific and SCS. It has been reported that the trajectory of the Kuroshio has varied with decadal climate changes. However, there has been no report of an observation-based estimate of the variation in the Luzon Strait transport. Here, a 50-year, high-resolution coral skeletal radiocarbon (Δ14C) dataset from 1946 to 1994 is reported from Currimao, northwest of Luzon Island. Δ14C has been used as a sensitive tracer of seawater, and our data indicates a significant increase in Δ14C from 1946 to 1994 related to atmospheric nuclear bomb testing, with more rapid increase in the SCS than in the Pacific. The unusual, rapid Δ14C increase in the 1950s found in our SCS corals together with seasonal variation in Δ14C will helps constrain physical oceanographic models for the western Pacific, including the SCS.

To investigate the relationship between paleoenvironmental changes and marine reservoir effects, the radiocarbon ages of marine bioclasts and terrestrial plants from the same horizons of a sediment core in the Holocene Epoch were measured. This core, with a length of approximately 9 m, was obtained from the southern part of the Miyazaki Plain southeast of Kyushu Island, which faces the Kuroshio warm current. This drilling site is located in an uplift area associated with the subduction of the Philippine Sea Plate. Based on analyses of lithology, molluscan and foraminifera assemblages, and radiocarbon dating, we interpreted four sedimentary units in order of age: tidal flat, inner bay, Kikai-Akahoya volcanic ash, and delta plain. These paleoenvironmental changes were mainly associated with the sea-level rise during the deglacial period. The reservoir ages of nine pairs from the tidal flat to inner bay facies were found to be from the time span of 7300–8200 cal BP. The chronological changes in the reservoir effect are correlated with those seen in Holocene sediments of the other coastal area in East Asia.

To identify chronological changes in the marine reservoir effect in southwest Japan, the radiocarbon ages of eight pairs of marine shells and terrestrial plants were measured from the same horizons of one core of Holocene sediments. This core was obtained from the northern part of the Sukumo Plain in southwestern Shikoku Island, which faces the warm Kuroshio Current. The drilling site is located in an area of subsidence associated with the convergence of the Philippine Sea Plate and the Eurasian Plate. On analyses of lithology, molluscan assemblages, and radiocarbon dating, we interpreted, from oldest to youngest, nine units: basement rock, a braided river channel, a meandering river channel, an estuary, a transgressive inner bay, Kikai-Akahoya volcanic ash, a deltaic inner bay, a tidal flat, and artificial soil. Changes in the depositional environment were mainly associated with sea-level rise after the end of the last glaciation. The reservoir ages of the eight pairs, 330 ± 70 yr, were obtained from a transgressive inner bay to deltaic inner bay sediments, formed during 4100–9200 cal BP. The chronological change in the reservoir effect allows us to correlate the Sukumo Core sediments with previous results from southwestern Japan, the Korean Peninsula, and Taiwan Island.

The Trondheim radiocarbon (14C) laboratory has evolved from a traditional radiocarbon decay counting laboratory to an accelerator mass spectrometry (AMS) facility primarily measuring 14C. This evolution required adjustments in sample preparation and data handling to match the capacity of the AMS system and reduction in sample sizes to about 1 mgC. We summarize here the steps involved in dating a sample at the National Laboratory for Age Determination in Trondheim, Norway. These include the structure of our sample database for information handling, sample cleaning procedures for different sample types, our reduction systems, both an automated EA-based system for regular use and a manual system for more challenging samples, and data evaluation. We will also briefly summarize the capabilities of our isotope-ratio mass spectrometer.

The ENEA Radiocarbon Laboratory (Bologna, Italy) has been operating since 1985; it is the oldest among such laboratories operating in Italy and has been active for about 30 years in the field of dating of different types of samples with the radiocarbon (14C) liquid scintillation method. This study shows the detailed procedure for radiocarbon analysis on bioplastic materials by means of the synthesis of benzene, which includes CO2 production and purification, synthesis of acetylene, and synthesis and collection of benzene. The changes made to the original design of the synthesis procedures and the operational parameters adopted to optimize the combustion of the plastic materials are described. The measurement of 14C activity was performed using the liquid scintillation counting technique by a QuantulusTM 1220 low-background counter. The δ13C content was compared with the percentage of 14C concentration for the characterization of the bio content in plastic used in the food packaging.

Despite many ideas about the age and processes of sand movements and paleosol formation, there are still some uncertainties in this relations in the Nyírség, eastern Hungary. The major aim of the present study was to clarify the chronology of fossil soils and blown-sand layers in the sand dunes of the Nyírség using radiocarbon (14C) dating on soil and charcoal samples. Charcoal and soil samples were collected from buried paleosols from different sand quarries for 14C dating. The bulk organic carbon content of the buried soil and charcoal pieces recovered from buried fossil soil layers allowed parallel 14C accelerator mass spectrometry dating in several cases. The new 14C results indicate paleosol development during Younger Dryas, while the preceding interstadial was assumed as a cold and dry period when only sand movement occurred in the area. Our results also confirm and support the previous assumptions, that in the Late Glacial, the first paleosol development period was during the Bølling-Allerød Interstadial. Four soil-forming periods could be determined during the Holocene (Preboreal, Boreal, Atlantic, Subatlantic). We have also indirectly identified sand movements during the Oldest Dryas, Younger Dryas, Preboreal, Boreal, and Subatlantic phase in the study area.

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.

The aim of this study is to investigate the range, the degree of variability, and a possible time or species dependence of wood and charcoal δ13C values within one small study area. To achieve this, we used δ13C and 14C determinations of more than 400 archaeological samples from a ca. 300 ha area in Denmark, spanning 5000 years and covering several different species. The δ13C values of the wood and charcoal range from −32.8‰ to −21.2‰. We found no time-dependence of wood and charcoal δ13C values, neither in general nor within one species. The mean δ13C of all wood samples is −28.5‰, while the means of individual species range from −30.6‰ to −26.3‰. The mean of all charcoal samples is −25.7‰, with the means of individual species ranging from −28.1‰ to −24.3‰. The wood δ13C values can be used to infer the possible range of plant δ13C values, which otherwise are not available. They imply that a high degree of variability can be expected at the base of the food chain. This is relevant for palaeodietary studies that rely on the measurement of baseline isotope values.

The paper presents a discussion of 24 radiocarbon (14C) dates of organic material from deposits of various genesis within the intermountain depressions and valleys of the Russian Altai. These apparent 14C ages (sometimes near the upper time limit of the 14C dating method) contradict to other proxy data and optically stimulated luminescence (OSL) dates. Rejuvenation of ancient deposits by 14C dating encountered two problems: (1) wrong interpretation of previously unknown near-surface location of Tertiary deposits as being of the Pleistocene ones with the redeposited ancient flora; and (2) wrong age estimation of the Pleistocene-Holocene deposits with redeposited Carboniferous, Jurassic, and Neogene organic material, which is represented as inclusions. Significant scattering of 14C ages, their inversion within a section, and discrepancy with other proxy data indicate penetrating of the “young” carbon into ancient organic material, and its presence in a unique (for each sample) ratio. Today such contamination cannot be eliminated utilizing standard pre-treatment techniques. The influx of “young” carbon is related to post-sedimentation tectonic and exogenous processes, which are common for tectonically active mountain provinces including Altai. The reported problem is not a new one, although methodological studies in the Russian Altai have not yet been carried out earlier.