Temporal changes in soils of forest landscapes of the forest-steppe zone—Haplic Luvisols and Greyzemic Phaeozems—under the impact of Holocene climate changes (natural factor) and long-term cultivation (anthropogenic factor) were studied on level interfluves of the Central Russian Upland. These soils were developed from covering loesslike loam of varying thickness. To study soil evolution under the impact of climate changes, soil chronosequences of archaeological sites—paleosols buried under ramparts of ancient settlements and background surface soils of adjacent areas—were analyzed. The time of the soil burying was determined via the 14C dating of charcoal from thin twigs sampled in the material of ramparts immediately above the surface of buried soils. According to 14C dates, the paleosols were buried in the interval from 2450±40 to 1150±110 BP. Before the Subatlantic period, these paleosols developed under grassland (steppe), which is proved by their properties typical of steppe soils and by the presence of paleokrotovinas—the features created by the burrowing activity of steppe animals (mole rats)—in the studied profiles. The 14C dates of the total organic carbon of humus in the dark gray filling of a paleokrotovina from a Phaeozem buried at the depth of 140–150 cm under the rampart of 1150±110 BP in age ranged from 6080±150 to 2810±60 BP. The evolution of steppe Chernozems into forest Phaeozems and Luvisols took place in the Late Holocene. The anthropogenic evolution of forest Luvisols and Phaeozems under the impact of long-term (more than 150–230 years) plowing was analyzed in the soil agrochronosequences that included background soils under native forest vegetation and their arable analogs with different durations of cultivation. It was concluded that this evolution is directed towards Chernozemic pedogenesis, i.e., it proceeds in the direction opposite to the natural trend of pedogenesis in the Late Holocene. This process takes place despite the traditional practice of limited application of organic fertilizers in arable farming in the studied region. A decrease in the mean residence time (MRT) of total organic carbon (TOC) in the old-arable soils is considered a consequence of the formation and accumulation of fresh humus material in the profiles of cultivated soils—one of the major processes in the transformation of arable forest soils into Chernozems. The accumulation of carbonates and an increase in their 14C age take place in the arable soils in comparison with their forest analogs. In the agrochronosequence from the Polyana site, the 14C age of carbonates at the depth of 170–180 cm reaches 8000±100, 8270±150, and 9150±100 BP under the forest, 100-year-old plowland, and 150-year-old plowland, respectively. This can be explained by the ascending migration of ancient carbonates from the parent material in suspensions. In the analogous Samarino agrochronosequence, the 14C age of carbonates from the depth of 90–100 cm comprised 6500±90, 7150±100, and 12,360±230 BP, respectively. Thus, the studied forest-steppe soils have a polygenetic nature specified by a complicated history of pedogenesis under the impact of both natural (climate-driven forest invasion into steppe) and anthropogenic (deforestation and land plowing) factors.

Late Neolithic graves excavated at Tell Sabi Abyad, Syria, have been dated by radiocarbon. This series of 46 human bone dates represents a sequence of cemeteries that is analyzed by Bayesian methodology. The dates show continuous use of the northeastern slope of the mound as a burial ground throughout the Initial Pottery Neolithic to the Halaf period.

The requirements of extracting minute amounts of organic carbon in solution with high yield and minimum background are a prerequisite for radiocarbon dating of microgram amounts of carbon. Samples for biomedical or environmental research often arrive at the accelerator mass spectrometry (AMS) lab as concentrates dissolved in 1 mL of water or less. We have developed a new extraction method based on photo-oxidation by ultraviolet (UV) light. The solution is transferred into UV-transparent quartz vials with a head volume of pure oxygen and UV from low-pressure mercury discharge lamps is applied. To exclude the introduction of carbon background, we avoid any additional oxidizing agents. Under these conditions, only the 185 nm line is considered effective. To characterize the yield and the background, we have investigated artificial samples prepared from different materials. The setup developed allows parallel oxidation of 9 samples within typically 2 hr, connected directly to our graphitization setup for extremely small samples. The method was applied successfully for a study on dissolved organic carbon (DOC) in ice from 26 Austrian glaciers. A special advantage of the UV oxidation method in this case was that phosphoric acid could be used to remove carbonates, while its low vapor pressure prevented complete lyophilization. We see the most promising field of application in biomed research and compound-specific analysis.

We have isolated amino acid groups from modern bone hydrolysates and compared their relative Δ14C value to assess the carbon contribution of diet to the overall radiocarbon signal in bone. We find that both essential and non-essential amino acids may produce widely varying 14C, relative to other amino acid groups in the hydrolysate and to the original whole bone protein. We hypothesize that the 14C variations in non-essential amino acids may be due to metabolic effects that utilize essential amino acid carbon skeletons in the creation of non-essential amino acids.

Oracle bone script developed into a sophisticated writing system in Shang Dynasty of China more than 3000 years ago. The systematic scientific dating of oracle bones had not been previously reported. Here we present radiocarbon (14C) dates measured from the sequential samples of oracle bones that pertain to the Shang kings. The results indicate that King Wu Ding (who is called Wu Ting in some literature) reigned during 1254 BC to 1197 BC, and the Shang Dynasty terminated around 1041 BC. It also points that the Li group in the sequence of oracle bones is most probably related to the time of King Wu Ding and Zu Geng.

A new continuous sediment core (PY608W-PC; 3.8 m length) for reconstruction of climatic and environmental changes in the southeastern Tibetan Plateau was taken from the eastern part of Lake Pumoyum Co in August 2006. Sediment layers of the lower part of PY608W-PC (380–300 cm depth) were composed mainly of relatively large plant residues (up to ∼3 cm in length) with an admixture of fine sand and sandy silt. The large plant residues disappeared at ∼300–290 cm depth in core PY608W-PC and were replaced by silt-silty clay. The large plant residues from the lower part of PY608W-PC could be aquatic, because the plant residues were extremely enriched in 13C (up to –3.0‰, −5.6 ± 2.3‰ on average). On the other hand, the plant residue concentrates (PRC fractions) from the upper part of the core (290–0 cm in depth) could be terrestrial C3 plants (δ13C = –21.8 ± 1.7‰ on average). Radiocarbon dating was performed on the large plant residues and PRC fractions from the PY608W-PC sediment core, which represented the chronology from ∼19,000 cal BP to present.

Procedures and equipment have been described in previous date lists. Except as otherwise indicated, wood, charcoal and peat samples are pretreated with dilute NaOH and dilute H3PO4 before conversion to the counting gas methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HCL instead of H3PO4.

Many interlaboratory studies have been made in the 14C community at irregular intervals over the past ten years. At times, the results from these studies have been contentious, mostly because of the lack of consistency in their findings. The importance of regular exercises has become particularly acute due to the large number of operating laboratories and the diversity of their methodologies. Hence, we briefly review the studies that have been made in the 1980s, focusing on those in which our laboratories participated. These include the 14C Interlaboratory Comparison in the UK (Otlet et al 1980), the International Comparison (ISG 1982, 1983) and the first two parts of the current International Collaborative Program (Scott et al 1989a, b). The development of each study, its findings and shortcomings, are highlighted in order to assess the concordance of the conclusions.

Geochemical and palynological data as well as radiocarbon dating were used to study the peat bog deposits in Niinsarre bog, northeast Estonia. The aim of this study was to establish criteria for determining a detailed chronology, which is important, for example, in studying paleoevents and historical monitoring. In some cases, we can use cumulative pollen data, as well as cumulative chemical and peat bulk density data.

Chemical pretreatment and extraction techniques have been developed previously to extract in situ cosmogenic radiocarbon (in situ14C) from quartz and carbonate. These minerals can be found in most environments on Earth, but are usually absent from mafic terrains. To fill this gap, we conducted numerous experiments aimed at extracting in situ14C from olivine ((Fe,Mg)2SiO4). We were able to extract a stable and reproducible in situ14C component from olivine using stepped heating and a lithium metaborate (LiBO2) flux, following treatment with dilute HNO3 over a variety of experimental conditions. However, measured concentrations for samples from the Tabernacle Hill basalt flow (17.3 ± 0.3 ka4) in central Utah and the McCarty's basalt flow (3.0 ± 0.2 ka) in western New Mexico were significantly lower than expected based on exposure of olivine in our samples to cosmic rays at each site. The source of the discrepancy is not clear. We speculate that in situ14C atoms may not have been released from Mg-rich crystal lattices (the olivine composition at both sites was ∼Fo65Fa35). Alternatively, a portion of the 14C atoms released from the olivine grains may have become trapped in synthetic spinel-like minerals that were created in the olivine-flux mixture during the extraction process, or were simply retained in the mixture itself. Regardless, the magnitude of the discrepancy appears to be inversely proportional to the Fe/(Fe+Mg) ratio of the olivine separates. If we apply a simple correction factor based on the chemical composition of the separates, then corrected in situ14C concentrations are similar to theoretical values at both sites. At this time, we do not know if this agreement is fortuitous or real. Future research should include measurement of in situ14C concentrations in olivine from known-age basalt flows with different chemical compositions (i.e. more Fe-rich) to determine if this correction is robust for all olivine-bearing rocks.

Our standard procedure of 14C concentration measurements is reported in Riga I. We report here data on samples from the Latvian SSR and Eastern Siberia.

All measurements reported in the previous date lists (Kusumgar et al., 1963a; Agrawal et al., 1964 and 1965a) were based on acetylene counting. Since September 1964 we have changed over to methane counting and all dates presented here are based on this method. Methane counting offers certain advantages over acetylene, e.g., (1) rapid synthesis, (2) the non-explosive nature of gas, (3) the synthesized gas is radon-free. The disadvantage of having only one atom per molecule in methane (CH4), as against two in acetylene (C2H2), is compensated by the fact that methane can be counted at higher pressures with relatively low operating voltages.

In this paper we discuss recent developments in documenting the spread of millet across the Eurasian steppes. We emphasize that, despite a recent proposal that millet consumption in southern Siberia can be attributed to the Early Bronze Age (i.e., the late third to early second millennium BC), at present there are no direct data for southern Siberia indicating the consumption of millet prior to the Late Bronze Age, from the 14th century BC. We also present in full the combined stable isotope and 14C datasets from the Minusinsk Basin to support this conclusion.

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.

In the two years since the first successful measurements of 14C by high energy mass spectrometry, the advantages and the basic techniques of the method have been sufficiently reported. They will not be repeated here. This paper describes the work being done at Oxford to fill the gap between demonstrating the effectiveness of the approach and the creation of a facility dedicated to the carbon dating of milligram samples.

14C apparent ages along with δ13C values for three different fractions of humic matter (HM) isolated from a suite of four paleosols (PAs) interbedded within tephra are reported. The dated HM fractions were: 1) HA, the easily released humic acids; 2) HAtot, the bulk of humic acids; 3) RES, the insoluble HM. The 14C sequence dated from 13,000–25,000 BP, in agreement with stratigraphy and previous data. Age differences up to 2540±430 were statistically significant among fractions; their order of magnitude being independent from C content and depth. All the PAs showed a common pattern of among-fraction age variation, 14C aging trending from RES to HAtot through HA. As the HM fractions exhibited quite comparable δ13C values (δ13C = −25.4±0.2), it is inferred that the primitive organic matter (OM) input to PAs was dominantly supplied by vegetation of C-3 photosynthetic pathway which underwent complete decomposition during diagenesis.

We present a survey of carbon beam yields from 20 simple carbon compounds using a caesium sputter source and the McMaster University tandem accelerator. The carbon yield was measured as a 35MeV 12C4+ beam. We found that the beam intensities could be related to a grouping of the carbides according to the chemical bonding of the compounds. The usefulness of the compounds for accelerator 14C dating was further related to their preparation chemistries. Strontium carbide was the equal of graphite in negative carbon ion beam production and aluminum carbide was found to be a good candidate for further tests because of its good sputter yield and preparation chemistry. Charcoal was also tested with varying amounts of silver added as a heat conduction aid.

This article investigates the marine reservoir effects from apparent age differences among molluskan shells, birds, and sea mammals from the Hamanaka 2 archaeological site, Rebun Island, Japan, which was occupied during the latter half of the Late Jomon period (1300−1200 cal BC). The radiocarbon ages were younger in the order of charred wood<marine molluskan shells<Alcidae<Japanese sea lion≤charred materials on potsherds. According to data from molluskan shells from the site, the local marine reservoir correction (ΔR) for the Soya Warm Current, which flows near Rebun Island, was 172±39 14C yr. ΔR values of bone collagen for Alcidae (a family of seabirds) and Japanese sea lion were 289 and 389 14C yr, respectively. A ΔR value of 447±55 14C yr was obtained on charred material from the inner surfaces of potsherds at Hamanaka 2. The different reservoir effects relate to the differences in the diets or habitats of the shellfish, sea lion, and seabird remains at the site.

Increasing demands for small-scale radiocarbon (14C) analyses required the installation of a “SO-110 B” type ion source (HVE Europa B.V.) at our 6 MV Tandetron AMS (HVE) dedicated for the direct injection of CO2 using either the gas injection system (GIS) from Ionplus AG or a EuroVector EA 3000 elemental analyzer (EA). We tested both systems with multiple series of 14C-free and modern standards (2.5–50 µg C) combusted in quartz ampoules or EA containers and were able to quantify exogenous C introduced. In EA-GIS-AMS analysis exogenous C is mainly derived from the EA sample containers. Blank values for 50 µg C combusted in solvent-cleaned tin (Sn) vessels were 0.0127 ± 0.0012 F14C (boats) and 0.0090 ± 0.0010 F14C (capsules), while they were much higher for thermally cleaned silver (Ag) capsules. The processing of gas samples for GIS-AMS yields similar blank values corresponding to 0.30 ± 0.08 µg exogenous C with 0.93 ± 0.23 F14C consisting of 0.28 µg C modern and 0.02 µg C fossil C. The combustion of larger amounts of blank material (1 mg C) in a single quartz tube split into aliquots gives lower blanks (0.0064 ± 0.0008 F14C; 50 µg C). Thus, 14C analysis of small, gaseous samples is now possible at CologneAMS.

We have measured the concentration of 36Cl in 67 samples from the upper portion of the Camp Century ice core. The profile extends from AD 1265 to 1865 and covers the times of the Wolf (AD 1282–1342), Spoerer (AD 1416–1534) and Maunder (AD 1645–1715) minima in sunspot number. Although the profile exhibits much short-term variation, a smoothed plot of the data shows a strong peak in 36Cl concentration over the time of the Maunder Minimum. The deeper part of the core suggests increased deposition of 36Cl over the periods of the Wolf and Spoerer minima. The time resolution of the profile is inadequate for testing for an 11-year periodicity in our data. The data augment evidence from 10Be and 14C studies which indicate solar modulation of radioisotope production. Since, however, much of the short-term variation of 36Cl seems to be independent of solar activity, other factors must affect the deposition of 36Cl in ice. These variations could be due in part to mechanisms affecting the transport of 36Cl in the atmosphere. Based on our data from Camp Century, we calculate an average input of 36Cl of 24 atoms/m2 sec.