Carbonaceous particles that comprise organic carbon (OC) and elemental carbon (EC) are of increasing interest in climate research because of their influence on the radiation balance of the Earth. The radiocarbon determination of particulate OC and EC extracted from ice cores provides a powerful tool to reconstruct the long-term natural and anthropogenic emissions of carbonaceous particles. However, this 14C-based source apportionment method has not been applied for the firn section, which is the uppermost part of Alpine glaciers with a typical thickness of up to 50 m. In contrast to glacier ice, firn samples are more easily contaminated through drilling and handling operations. In this study, an alternative decontamination method for firn samples consisting of chiselling off the outer parts instead of rinsing them was developed and verified. The obtained procedural blank of 2.8 ± 0.8 μg C for OC is a factor of 2 higher compared to the rinsing method used for ice, but still relatively low compared to the typical OC concentration in firn samples from Alpine glaciers. The EC blank of 0.3 ± 0.1 μg C is similar for both methods. For separation of OC and EC for subsequent 14C analysis, a thermal-optical method instead of the purely thermal method was applied for the first time to firn and ice samples, resulting in a reduced uncertainty of both the mass and 14C determination. OC and EC concentrations as well as their corresponding fraction of modern for firn and ice samples from Fiescherhorn and Jungfraujoch agree well with published results, validating the new method.

Data on the emergence of pottery and agriculture in Eurasia were analyzed from the view of their spatiotemporal relationship. It was found that there are 2 major types of association between pottery and agriculture: 1) East Asian, with pottery as the main criterion of the Neolithization; and 2) Levantine, with agriculture as the phenomenon most closely related to the emergence of the Neolithic. Some regions of Eurasia have intermediate characteristics. The concept of a single area for pottery origin in eastern Eurasia and its subsequent spread to the west, still used by some scholars, is the revival of the old diffusionist paradigm and does not seem to advance the analysis of the Neolithization process. If the wheat/barley agriculture definitely originated in the Levantine “core” and spread toward Anatolia and central/western Europe, it is impossible to apply the same approach to pottery. The latest developments in chronology of the earliest ceramics in China, one of the key regions in the world in terms of the origin of pottery-making, are critically evaluated.

We conducted an interlaboratory comparison between our radiocarbon-related research group at Lund University and the established ETH-Zurich facility to test the quality of the results obtained in Lund and to identify sources of potential background differences and scatter. We did find differences between the 2 laboratories in the contributions of chemical preparation, graphitization, and measurements to the overall background. The resulting overall background is, however, almost similar. Multiple measurements on 2 wood samples of known calendar age yield consistent and accurate 14C ages in both laboratories. However, one of our known samples indicates that IntCal09 is ≃38 ± 16 14C BP too young at 7020 calendar yr BP, which is consistent with one of the raw data sets contributing to IntCal09. Overall, our results show that a systematic approach to compare the different steps involved in 14C age determination is a useful exercise to pinpoint targets for improvement of lab routines and assess interlaboratory differences. These effects do not necessarily become apparent when comparing 14C measurements that integrate over the whole process of preparation and measurement of different laboratories.

Our updated database of Siberian Paleolithic radiocarbon records (the 2011 date list of ∼800 values) was used to analyze the patterns of population changes, following the methodology developed previously (Kuzmin and Keates 2005). Although the main conclusions remain similar to our 2005 results, some new features were also detected. The intensity of occupation after ∼35,000–34,000 BP was higher than previously thought, and the rise in population began at ∼20,000–19,000 BP. It is once again confirmed that no significant decline can be observed for the Last Glacial Maximum (∼22,000–16,000 BP). The relationship between climate and Paleolithic humans in Siberia was complex and without a clear trend toward the intensification of occupation during the warm phases.

This study reports radiocarbon dates of more than 30 samples of charred residues on pottery sherds of the Incipient Jomon period. The ages of Linear-relief (Ryukisenmon) pottery were 15,300–13,700 cal BP, with great differences among the samples. The pitted decoration (Enkomon), Nail-impressed (Tsumegatamon), and pressing and dragging (Oshibikimon) types date to 13,800–12,400 cal BP. For pottery of the same type, differences among sites were large. At the Unokiminami site, the impressed cord mark (Oatsu Jomon) is the main pottery type, including Nail-impressed. The latter shows a slightly older age. Stable isotope and elemental analyses were used to ascertain the origin of charred residues on the pottery. In the data set of Jomon pottery of the oldest type, residues consisting only of cooked nuts were found. However, Jomon people, even from early times, are thought to have cooked mixed plant and animal ingredients, including marine products.

Preservation of seawater samples was tested for total inorganic carbon (∑CO2), stable carbon isotope (δ13C), and radiocarbon (14C) applications using foil bags and storage by refrigeration and freezing. The aim was to preserve representative samples with minimal storage effects but without using toxic methods such as mercuric chloride poisoning. Hydrolysis of samples to CO2 was based on existing methods. Results of IAEA-C2 standard used with deionized water stored in the foil bags showed complete reaction yields, 14C results within 2σ of the consensus value, and δ13C that were internally consistent, indicating that there were no procedural effects associated with the foil bags. 14C results were statistically indistinguishable across the storage times, for frozen and refrigerated seawater samples from a coastal site, Elie Ness, Fife, UK. The scatter of ∑CO2 concentrations and δ13C was within scatter observed in other studies for lake- and seawater samples preserved by acidification or using mercuric chloride. However, both ∑CO2 and δ13C were less variable for frozen samples compared with refrigerated samples. The foil bags are lighter, safer to transport, and similar in cost to glass bottles and allow sample collection in the field and transfer to the hydrolysis vessel without exposure of the sample to atmosphere. Storage of seawater samples in the foil bags was considered a reliable, alternative method to poisoning for ∑CO2, δ13C, and 14C, and freezing the samples is recommended for storage time beyond a week.

Cartridges containing a zeolite molecular sieve are used for the field collection of CO2 from a variety of environments (e.g. atmosphere, soil respiration, evasion from surface waters) for accelerator mass spectrometry (AMS) radiocarbon analysis by the NERC Radiocarbon Facility. Previously, sample CO2 was recovered from the sieves by heating under vacuum prior to cryogenic purification and graphitization. An additional heating and evacuation stage was used to prepare the cartridge for the next sample. We have recently developed an alternative method using heating and purging with nitrogen gas to remove sample CO2 from the molecular sieve. An infrared gas analyzer (IRGA) is used to continuously monitor CO2 content in the purge gas. The preparation of the molecular sieve cartridge for the next use is performed simultaneously and the IRGA reading is used to verify that all sample CO2 has been removed from the sieve, ensuring insignificant carryover of CO2 into the next sample. We present the results of a suite of standards of distinctly different 14C and stable-carbon isotope composition, which we used to confirm the reliability of the new procedure. The new method has considerably reduced the time required to process a single sample from at least 2 hr to less than 40 min, and reduced the minimum sample size by 50%.

This study reconstructs food habits through carbon and nitrogen isotope analysis, and C/N analysis of charred residues inside pottery from Amur River sites in Russia (Goncharka 1 site, Novotroitskoe 10 site, Kondon 1 site) and in Hokkaido, Japan (Taisho 3 site, Yachiyo A site). We obtained dates from 12,330 to 7920 BP for these sites. There are major differences in the carbon and nitrogen isotope ratios between the Taisho 3 site (δ13C: -21.7 to -24.1; δ15N: 11.9–14.7%) and the other sites (δ13C:-22.0 to -27.1%; δ15N: 7.1–13.1%), suggesting that the people of the Taisho 3 site made use of anadromous fish such as salmonids and some species of trout, as well as marine resources. The dates from the other sites except Taisho 3 were assumed to be from a mixture of marine foods, C3 plants and terrestrial animals, and freshwater fish. The food boiled in the pots also indicated a high dependence on marine resources during the initial stages of the emergence of pottery.

In Korean Paleolithic archaeology, it is traditionally thought that the Late Paleolithic stone tool industries were in some way derived from the Shuidonggou site in northern China. The latter site has long been considered to be the type site of the eastern Asian Late Paleolithic blade technology. However, recent studies suggest that a number of Korean Late Paleolithic sites probably predate Shuidonggou, some by several thousands of years. Here, we present a series of accelerator mass spectrometry (AMS) dates recently analyzed by the AMS laboratory at Seoul National University and discuss further the possibility that the introduction of blade (and later microblade) technologies into Korea may have originated directly from Mongolia, Siberia, and possibly other areas of northeast China, rather than from Shuidonggou.

Molecular sieves are a promising way to sample and manipulate gaseous samples for radiocarbon analyses. Molecular sieve material can adsorb CO2 selectively, enabling sampling of CO2 from large air volumes in a small amount of adsorbent. The sieve material can be regenerated via heating and reused without removing the sieve material from its container. This results in ease of use and reduced risks of atmospheric contamination. Because sieve container volume is small and can be filled with synthetic air or nitrogen, it does not introduce underpressure to the system under study. Hence, sieves are suitable for many different experimental setups, from collection of CO2 from small soil chambers to atmospheric CO2 collection. The most common sieve material in use for sampling CO2 is the 13X zeolite. For environmental measurements starting this year, we have studied the properties of 13X zeolites in more detail. For reliable 14CO2 sampling, there are several caveats that should and can be avoided. In this contribution, we discuss these caveats and solutions to optimize the molecular sieve sampling process.

The Neolithic in Korea began around 10,000 BP and is the period when many substantial changes appear in the archaeological record. In particular, one of the important changes is from a subsistence strategy that relied primarily on hunted, fished, and collected food packages to a diet that by the beginning of the Bronze Age (∼3500 BP) saw intensive agriculture as the primary form of sustenance. This paper discusses current research on this topic, in addition to presenting a comprehensive list of raw accelerator mass spectrometry (AMS) data from Korean Neolithic sites, particularly data that only became available over the past several years.

At the Seoul National University accelerator mass spectrometry (AMS) laboratory, we are planning to develop an automated sample preparation system for higher throughput of radiocarbon dating. This system will consist of several sections, including a combustion line, CO2 trap, graphitization system, and so on. We usually collect CO2 by cryogenic trapping. However, since handling liquid nitrogen is expected to be rather difficult, we are interested in replacing the cryogenic method with the molecular sieve method for the collection of CO2. In this study, we compare the performance of the cryogenic trapping method and molecular sieve method. Zeolite 13X is used as a molecular sieve, and as test samples we use the oxalic acid standard (NIST SRM 4990C), high-purity graphite powder, and archaeological charcoals. The pMC values and the radiocarbon ages (BP) obtained from samples prepared by the above 2 methods are very similar. We especially focused on the memory effect of the molecular sieve, meaning the CO2 contamination from a previous sample, which can cause errors in age determination. To reduce this effect, we flowed He gas through a zeolite container for several minutes at a high temperature before the CO2 was introduced. By the adding this step, we have obtained more reliable results.

We had the opportunity to collect valuable wooden core samples from historic monasteries, temples, and secular buildings in 4 regions of High Asia, namely Dolpo (Nepal), ancient Nyangpo, Gyalrong/Minyag, and Lhasa and surroundings (all on the Tibetan Plateau, China). Tree species collected for dating include Pinus wallichiana (Dolpo), Juniperus tibetica, Pinus densata and several species of the genera Picea (spruce), Larix (larch), and Abies (fir) on the Tibetan Plateau, which could not always be determined to the species level due to the parallel occurrence of species of the same genus in these regions. Some of the wood samples were successfully dendro-dated with local tree-ring chronologies, but many could not, indicating a potentially higher age than the existing local chronologies. By accelerator mass spectrometry (AMS) dating and wiggle-matching 199 14C samples from 73 collected timbers, it was possible to date these wood samples with high precision, and important information about the possible time of construction of these important historic buildings was obtained for the first time. Floating chronologies of 14C-dated wood span the periods AD 650 to 900 in Dolpo and ∼200 BC to AD 420 on the Tibetan Plateau. Besides dating of the wood samples from these historic monuments, 14C AMS dating with wiggle-matching gives the opportunity to extend the range of the currently existing regional tree-ring chronologies for future environmental reconstructions on the Tibetan Plateau and the Himalayas.

It has been reported that the characteristics of a very old wood charcoal sample are different from those of modern wood charcoal according to its state of preservation (Cohen-Ofri et al. 2006; Rebollo et al. 2008). It can be assumed that these differences may lead to some difficulties when radiocarbon dating very old wood charcoal samples. To investigate this problem, we studied a carbonized trunk of Prunus pendula for. acendens tree buried in lava and found at the Hantan River lava plateau on the Korean Peninsula. The 14C date of this sample was previously measured as >30,000 BP. However, separate 14C results of its outer crust and inner wood showed a considerable difference, exceeding the estimated age differences by tree-ring counting. To study the reason for this discrepancy, optical microscopy and FTIR (Fourier transform infrared spectroscopy) were performed to examine the differences in the structural and chemical states of the samples. For reference data and to expand our understanding of very old wood charcoal, we applied the same analysis tools (AMS, FTIR, FE-SEM, EDS, and optical microscopy) to a variety of wood charcoals and original wood. From these analyses, we noticed considerable chemical changes in the outer crust sample, and this might explain the age discrepancy. Although it seems that the age difference might be due to the digestion of 14C-free CO2 from a volcanic environment, this explanation would not account for such a large value in the age difference.

Several canoes were excavated from coastal rivers in the Guangxi Zhuang Autonomous Region, southwest China. In order to confirm the age of the canoes, 6 samples were selected for radiocarbon dating from 3 canoes. The mean value of canoe NLJ was 365 ± 35 BP, and 2 samples from canoes MLJ and DFJ were 520 ± 21 and 499 ± 33 BP, respectively. The calendar ages cover a period from AD 1328 to 1641 at the 95% confidence level. These results disagree with previous studies that suggested canoes were only used over 1000 yr ago in China. We discuss the possible reasons for the results being younger than expected.

Direct dating of prehistoric paintings is playing a major role in Paleolithic art studies. Very few figures can be directly dated since the necessary condition is that they contain organic carbon-based material. Thus, it is very important to check the presence of organic carbon-based material in situ before sampling in order to protect the visual integrity of the paintings or drawings. We have tested and compared 3 different portable analytical systems that can be used in cave environments for detecting carbon in prehistoric paintings: (1) a very compact X-ray fluorescence (XRF) system in Villars Cave (Dordogne, France); (2) a portable micro-Raman spectrometer in Rouffignac Cave (Dordogne, France); and (3) an infrared reflectography camera in both caves. These techniques have been chosen for their non-destructiveness: no sample has to be taken from the rock surface and no contact is made between the probes and the paintings or drawings. The analyses have shown that all the animal figures have been drawn with manganese oxides and cannot be directly dated by radiocarbon. However, carbon has been detected in several spots such as black dots and lines and torch marks. 14C results were obtained from 5 torch marks selected in Villars Cave, with ages between 17.1–18.0 ka cal BP. Three methods were used to identify carbon in black pigments or to confirm the presence of torch marks by carbon detection. Thanks to these new analytical developments, it will be now possible to select more accurately the samples to be taken for 14C dating prehistoric paintings and drawings.

Two recently published sets of radiocarbon dates, one from Mesopotamia and one from Anatolia, gave anomalous results. On the basis of historical analysis, both sets were expected to date to the 7th century BC. However, the 14C results were more than a century older than this. We tested samples from an Egyptian mummy, also historically dated to the 7th century BC, to see if such discrepancies were more widespread at this time. We did not find evidence of such a problem, but the results do provide insights into the reuse of old wood in ancient Egyptian coffins. We include publication of an earlier set of dates from the same mummy and coffin set.

Archaeological bones are now routinely dated in many radiocarbon laboratories through the extraction of “collagen.” Methods for “collagen” extraction vary, and several laboratories now apply an ultrafiltration step after gelatinization to extract the higher molecular weight (usually >10 or 30kDa) fraction for dating, thereby removing low molecular weight contaminants. Ultrafiltration has been demonstrated to result in products that are easier to handle and have more acceptable C:N ratios, and in some instances can result in significantly improved (generally older) 14C dates when compared to non-ultrafiltered products from the same bone. Although it has been suggested that ultrafiltration removes potential contaminants such as short-chain degraded collagen and other peptides and amino acids, fulvic acids, and salts, there remains little published evidence to support this. This paper presents data from a pilot study investigating the most suitable techniques with which to study the products of the routine “collagen” extraction procedures employed at the Oxford Radiocarbon Accelerator Unit (ORAU) (modified Longin followed by ultrafiltration). The preliminary data demonstrates that the final product of “collagen” extraction at ORAU appears to be an aggregate consisting of a range of proteins of different molecular weights, including collagen, as well as some other organic matter and inorganic species. Ultrafiltration is removing some, but not all, of the <30kDa fraction from the samples. Further work to investigate the nature of this aggregate and how best to improve the efficiency of “collagen” extraction procedures is discussed.

We investigated the radiocarbon age and stable isotope composition of bioapatite from bone, enamel, and dentine material from 3 different species of extinct mammals in South America. Most samples of Eremotherium laurillardi, Toxodon platensis, and Notiomastodon platensis were collected in natural depressions located in the northeastern Brazilian provinces of Sergipe, Bahia, and Rio Grande do Norte. All samples studied were devoid of collagen, which had decomposed as a result of high microbiological activity in this tropical region. We have instead analyzed the bioapatite fraction of the samples, which was relatively well preserved even in these harsh tropical conditions. The mineral fraction of bone and tooth material does not usually undergo microbiological decomposition but may be exposed to isotopic exchange with environmental carbonates. The problem thus becomes one of separating the diagenetic carbonates without destroying the bioapatite. We offer a technique for removing the secondary diagenetic carbonates by treatment with diluted acetic acid in a vacuum. We also demonstrate that proper pretreatment of bone and tooth samples allows the separation of diagenetic carbonates from bioapatite, as long as the carbon in these samples has not degraded completely. Bone, enamel, and dentine samples from individuals of the 3 mammalian species were dated using this technique and were compared to results by other researchers from the literature. Date ranges for the species presented were in good agreement with prior research. A comparison with other dating techniques such as U/Th and ESR shows the reliability of the treatment described and the feasibility of 14C dating the bioapatite fraction given certain conditions. In 2 cases, we dated bone enamel and dentine samples from the same individuals of N. platensis, with results between 14 and 21 ka. Results from dating samples of T. platensis are between 11.5 and 13 ka. The oldest tissue in both cases was dentine. The dating of enamel and dentine from the same species did not show regular differences; however, more often the dentine material was older. The oldest date, ≃22.5 ka for E. laurillardi, was obtained on the bioapatite fraction of dentine.