This study employs tree-ring crossdating and radiocarbon measurements to determine the precise calendar age of the Bes-Shatyr Saka necropolis (43°47′N, 81°21′E) built for wealthy tribe leaders in the Ili River Valley (Semirechiye), southern Kazakhstan. We developed a 218-yr tree-ring chronology and a highly resolved sequence of 14C from timbers of Bes-Shatyr kurgan #3. A 4-decadal-point 14C wiggle dates the Bes-Shatyr necropolis to 600 cal BC. A 47-yr range of cutting dates adjusted the kurgan date to ∼550 BC. This is the first result of high-resolution 14C dating produced for the Saka burials in the Semirechiye. The collective dating of Bes-Shatyr indicates the early appearance of the Saka necropolis in the Semirechiye eastern margins of the Saka dispersal. However, the date is a couple of centuries younger than previously suggested by single 14C dates. It is likely that the Shilbiyr sanctuary (location of the Bes-Shatyr) became a strategic and sacral place for the Saka leadership in the Semirechiye long before 550 BC. Another prominent feature of the Semirechiye burial landscape, the Issyk necropolis enclosing the Golden Warrior tomb, appeared a few centuries later according to 14C dating reported by other investigators. This study contributes to the Iron Age chronology of Inner Asia, demonstrating successful results of 14C calibration within the Hallstatt Plateau of the 14C calibration curve. It appears that the wide range of calibrated dates for the Saka occurrences in Kazakhstan (from 800 BC to AD 350) is the result of the calibration curve constraints around the middle of the 1st millennium BC.

In the opencast mine area of Zwenkau, Germany, many prehistoric wells and pits have recently been excavated. In this region there is generally no bone preservation and charred seeds are rare, seldom encountered in a reliable archaeological context, whereas charcoal is frequently found. From an archaeological point of view, however, charcoal from wood is not as reliable for radiocarbon dating as short-lived materials. Fortunately, many deep features were found where wood has been preserved. Over a dozen structures turned out to be prehistoric wells, some of them typologically dated by ceramics to between Early Bronze Age and Early Middle Ages. For other features without archaeological finds, 14C dating was the only way to get an age. Analysis showed that different types of wells were constructed by the same culture. On the other hand, the same constructions are not characteristic for a defined cultural period and were applied over a time span of three millennia.

A dedicated sample processing line for the extraction of dissolved inorganic carbon (DIC) from seawater and groundwater for accelerator mass spectrometry (AMS) radiocarbon analysis has been developed at CEDAD, the Center for Dating and Diagnostic of the University of Salento, Lecce, Italy. The features of the new system are presented together with tests carried out to determine its functionality and background levels. The first results obtained at CEDAD for analyzing seawater samples taken from the Northern Adriatic compare well with results obtained for the same samples analyzed at ETH Zurich.

The distribution of bomb-produced 14C in the ocean provides a powerful constraint for circulation models of upper ocean mixing. We report 14C measurements from an east-west section of the main thermocline at 24°N latitude in the subtropical North Atlantic Ocean in summer 1992, and one profile from the Gulf of Mexico in 1993. Observed gradients reflect the transient invasion of bomb 14C into the thermocline via mixing along isopycnals from the poleward outcrop, with progressively more sluggish mixing at greater depths. A slight deepening of the profile is observed over the 20-yr period since the GEOSECS survey at one location where the comparison is possible.

Accurate radiocarbon ages were obtained from terrestrial moss from two drill holes in Tern Lake deposits, Antarctica, using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS). The results show that the lake deposits have been accumulating since the end of the last glacial epoch ca. 12,600 cal BP at the rate of 0.13–1.1 mm a-1. We discuss the validity of 14C ages of Antarctic lake deposits, with respect to the latitude effect of 14C productivity, the reservoir effect, the environment effect and the hard-water effect.

Sea surface reservoir ages (R) are reported from radiocarbon (14C) measurements of the annual growth bands of coral Siderastrea siderea collected on the Atlantic coast off Martinique Island, in the Lesser Antilles volcanic arc. Mean values of R are similar between 1835 and 1845 during pre-anthropogenic times at 385±30 yr and between 1895 and 1905 at 382±20 yr when there was a huge eruption from the Montagne Pelée volcano in 1902–1903. Limited 14C aging of sea surface (~40 yr) may be due to enhanced volcanic activity. Variability of R is slightly greater during 1835–1845 than during 1895–1905. It is linked to a moderate increase of ∆14C of 5‰, strengthened by a clear increase of δ18O of 0.4‰. This is attributed to a decrease of the northward advection of the South Atlantic Waters into the western tropical North Atlantic and Caribbean Sea and relative enhanced westward flux of the tropical North Atlantic surface waters, the southern waters having lower values of 14C and δ18O than the North Atlantic ones. From 1835 to 1845, the fraction of the South Atlantic Waters transported up to Martinique Island was reduced from 25% to 15%.

The Sellafield nuclear fuel reprocessing plant is estimated to be the largest single source of global anthropogenic radiocarbon discharge. This study addresses the impact of these releases on the Irish coastal marine environment. Spatial trends in the 14C content of seaweed (Fucus spp.) were assessed by collecting and analyzing samples from well-distributed locations around the Irish coastline. Temporal trends were studied by comparing 14C concentrations in present-day samples with levels found in archive material collected at the same locations during research campaigns conducted in the mid-1980s and mid-1990s. The impact of 14C discharged from Sellafield was found to be most apparent in seaweeds from the northeastern Irish coast. This indicates that the pattern of residual currents and, in particular, the south to north transfer of water known to predominate in the Irish Sea, largely controls the spatial distribution of 14C releases. Maximum 14C discharge levels to the marine environment from Sellafield (between 12 and 13 TBq yr-1) were mirrored by peak concentrations found in seaweed from the mid-1990s and in present-day samples (highest recorded value of 130.4 pMC). Concentrations of 14C in seaweed from the west coast of Ireland correspond closely with values measured for seaweeds from the Atlantic coast of northwest Spain and do not appear to be significantly affected by Sellafield discharges.

The 14C/12C ratio of living organisms is largely determined by the 14C/12C ratio of consumed diet as well as by the atmospheric 14C concentration together with the body’s metabolic processes. The measured 14C content of living matter compared to the atmospheric radiocarbon level can provide invaluable information about developmental processes. Our aim was to determine the 14C content of ten different tissues of the human eye using the 14C bomb-pulse dating signature. The 14C content of the atmosphere, so called 14C “bomb-pulse” has labeled humanity offering an opportunity to determine these special formation, turnover and substitution courses in biology. The results allowed us to construct a 14C map of the bomb-peak labeled human eye. According to the anatomical location of the tissues, an unexpected picture emerged as in moving from the outer parts towards the inner parts of the eye, the 14C content of each tissue decreased. The data presented here are compatible with the view that the oldest parts of the eye are the sclera, the limbus and the cornea, in this order, and moving further inside, the youngest tissue of the eye is the retina.

Up to now, Global Carbon Cycle Models (GCCM) have only represented the soil and biosphere in a very simplified way. For example, the High Resolution Biosphere Model (HRBM) (Esser 1987; Esser and Lautenschlager 1994) distinguishes five subreservoirs and determines the fluxes between them for selected area of a global grid. The models have not yet been sufficiently tested against global observations. Such testing is difficult because the observed variables are in turn dependent on the behavior of other geological carbon pools, e.g., the atmosphere and ocean.

Fruit carbonate of Buglossoides arvensis (syn. Lithospermum arvense) is a valuable dating and paleoenvironmental proxy for late Quaternary deposits and cultural layers because CaCO3 in fruit is assumed to be accumulated from photosynthetic carbon (C). However, considering the uptake of HCO3– by roots from soil solution, the estimated age could be too old depending on the source of HCO3– allocated in fruit carbonate. Until now, no studies have assessed the contributions of photosynthetic and soil C to the fruit carbonate. To evaluate this, the allocation of photo-assimilated carbon and root uptake of HCO3– was examined by radiocarbon (14C) labeling and tracing. B. arvensis was grown in carbonate-free and carbonate-containing soils (sand and loess, respectively), where 14C was provided as (1) 14CO2 in the atmosphere (5 times shoot pulse labeling), or (2) Na214CO3 in soil solution (root-labeling; 5 times by injecting labeled solution into the soil) during one month of fruit development. Distinctly different patterns of 14C distribution in plant organs after root- and shoot labeling showed the ability of B. arvensis to take up HCO3– from soil solution. The highest 14C activity from root labeling was recovered in roots, followed by shoots, fruit organics, and fruit carbonate. In contrast, 14C activity after shoot labeling was the highest in shoots, followed by fruit organics, roots and fruit carbonate. Total photo-assimilated C incorporated via shoot labeling in loess-grown plants was 1.51 mg lower than in sand, reflecting the presence of dissolved carbonate (i.e. CaCO3) in loess. Loess carbonate dissolution and root-respired CO2 in soil solution are both sources of HCO3– for root uptake. Considering this dilution effect by carbonates, the total incorporated HCO3– comprised 0.15% of C in fruit carbonate after 10 hr of shoot labeling. However, if the incorporated HCO3– during 10 hr of shoot labeling is extrapolated for the whole month of fruit development (i.e. 420-hr photoperiod), fruit carbonate in loess-grown plants incorporated approximately 6.3% more HCO3– than in sand. Therefore, fruit carbonates from plants grown on calcareous soils may yield overestimated 14C ages around 500 yr because of a few percentage uptake of HCO3– by roots. However, the age overestimation because of HCO3– uptake becomes insignificant in fruits older than approximately 11,000 yr due to increasing uncertainties in age determination.

The following date list presents results obtained during 1975-1977. The facilities at Glasgow have been further developed and include a gas counting system utilizing CO2 as counting material and two liquid scintillation counting laboratories based on synthesis of benzene. The results presented here were obtained using the liquid scintillation system only. Sample pretreatment varied according to individual sample type, whether wood or charcoal. The majority of samples were of preserved wood. After manual removal of gross contamination, samples of wood were finely chopped and digested in boiling, 2M KOH solution. The dehumified wood was then separated by filtration, thoroughly washed with distilled water and dilute hydrochloric acid, and then bleached in a solution of NaClO2/HCl at 80°C for 48 hours. Pure, white wood cellulose was obtained by filtration and washed with a large volume of distilled water. The cellulose, typically 40% by weight of the original material, was then dried overnight in an oven at 80°C. Samples of charcoal were closely examined for non-contemporaneous contamination and then subjected to successive treatments with hot, dilute (1M) KOH and HCL, respectively. The remaining charcoal was then dried overnight at 80°C.

14C activities of decadal samples from beech trees growing under extreme calcareous conditions were compared to 14C activities of decadal samples of the same age from a beech tree growing in a normal mold soil in order to see whether part of the carbon assimilated during photosynthesis might originate from 14C-deficient carbonates in the soil. The calcareous soils contained from 18 to 52% calcium carbonate, and this carbonate had a mean 14C age of 10,200 to 17,600 years BP. A comparison was also made with the 14C activity of contemporaneous samples from Douglas Fir from the US North Pacific (Stuiver, 1982).

No significant depletion in 14C activity in beech trees growing in the highly calcareous soils was detected. The measured mean difference in 14C activity in beech trees from calcareous and non-calcareous sites corresponds to an uptake of 0.12 ± 0.3% carbon from soil carbonates in the calcareous sites.

The Kuju volcanic group, located in central Kyushu, Japan, consists of small stratovolcanoes and lava domes. To refine the eruptive history of the group, we conducted accelerator mass spectrometry (AMS) radiocarbon dating of charcoal fragments from three pyroclastic-flow (PF) deposits on the southern slope. The obtained 14C dates are consistent with the geomorphology, stratigraphy, and thermoluminescence (TL) ages. The Handa PF deposits, which are products of the largest eruption of the group, were dated to ~53.5 ka BP. The Shirani and Muro PF deposits, which are block-and-ash flows, were dated to 44 to >50 cal ka BP and 35–39 cal ka BP, respectively. These ages can be correlated with TL ages for lava domes. This study demonstrates that the lava domes and associated PF deposits formed after the Handa eruption.

In hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

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.

A sample preparation workshop was convened at the 20th International Radiocarbon conference, with about 30–40 attendees. The term “sample preparation” was not further specified to allow participants to address the laboratory issues most important to them. Given the short time available, the focus quickly narrowed to details of graphite preparation for accelerator mass spectrometry (AMS), with particular interest in procedures for small samples, and hence we have changed the title to reflect the focus. Here, we summarize the workshop discussion, adding additional background information and references to publications. Several aspects of graphite preparation are included: catalyst types and ratio of catalyst to carbon; optimal reaction temperatures for various sample sizes; methods for water removal; types of pressure transducers; preconditioning of catalyst; and problems with blank values in very small samples. The pros and cons of sample dilution were also discussed.

The following list presents results obtained during 1970-1971 and is a continuation of research of which data have been pub. previously (Baxter et al., 1969; Ergin et al., 1970; Baxter and Walton, 1970; Harkness and Walton, 1972; Ergin et al., 1972). The major research efforts at Glasgow are aimed at evaluation of (a) natural annual C14 levels and (b) burdens and residence times of artificial C14 in the environment and human tissues. The results of these studies are presented as δC14 and Δ values based on age-corrected activities, although this correction is very small. The errors quoted are counting uncertainties only, expressed at the 1σ level. Pretreatment procedures are outlined in the text and analytical methods are essentially unchanged. Gas proportional counting of both CO2 and CH4 is employed in 2.6L and 0.5L detectors, respectively. Mass spectrometric analyses are performed to a precision of 0.1‰ (± 2σ) on a V.G. Micromass 602B stable isotope mass spectrometer.

We discuss a radiocarbon study of sediment samples collected from Nanfu terrace in western Taiwan. From these, we extracted humic acids (HA) and humin from the very fine and coarse grain-size fractions using a standard acid-alkali-acid pretreatment. The humin extracts were combusted at 400 and 1100 °C by stepped-combustion, to yield a low-temperature (LT) carbon component and a high-temperature (HT) carbon component. We compare the ages of the LT and HT humin fractions to the HA fractions, in samples collected at 2 depths within the Nanfu terrace. As in previous stepped-combustion studies on sediments, we find that the HA ages are the youngest on average, and overlap the LT ages, and that the carbon contained in the HT fraction is always distinctly older than the LT and HA ages. To better understand the relationship between 14C age and combustion temperature, we conducted an incremental stepped-combustion experiment with one of the samples (1E) using 50 °C steps that ranged from 300 to 1100 °C. The 14C results of the stepped-combustion products show a clear division between 2 isotopically identifiable carbon constituents, from carbon released below 400 °C and carbon released above 550 °C. By comparing the δ13C and 14C results, we find evidence for a third carbon isotopic component in the humin that is released when combusted at ∼500 °C.

Radiocarbon (14C) dating has been widely used to determine the age of deposits, but there have been frequent reports of inconsistencies in age among different dating materials. In this study, we performed radiocarbon dating on a total of 33 samples from 8-m-long sediment cores recovered from the wetland of the Muljangori volcanic cone on Jeju Island, South Korea. Ten pairs of humic acid (HA) and plant fragments (PF) samples, and three pairs of HA and humin samples, from the same depths were compared in terms of age. The PF were consistently younger than the HA. Interestingly, the age difference between HA and PF samples showed a long-term change during the past 8000 years. To test whether there was an association between this long-term age difference and climate change, we compared with the carbon/nitrogen (C/N) ratios and total organic carbon isotope (δ13CTOC) values of the sediments, as indicators of the relative abundance of terrestrial and aquatic plants; these parameters showed similar long-term trends. This suggests that the increasing (decreasing) trend in age difference was influenced by long-term dry (wet) climate change.

The paper “The effects of possible contamination on the radiocarbon dates of the Dead Sea Scrolls I: castor oil” by Rasmussen et al. (2001) is discussed. Detailed analysis of the extant dates of the Dead Sea Scrolls suggests that the pretreatment of the samples was adequate. Errors and omissions in the paper are discussed and the implications of the experiment of Rasmussen et al. (2001) are questioned.