This article reports on 12 new accelerator mass spectrometry (AMS) dates from the latest phases of the Chalcolithic period occupation (late 5th millennium cal BC) at Teleilat Ghassul, type site for the south Levantine Ghassulian Chalcolithic culture. The new AMS dates from Teleilat Ghassul favor an amendment to a previous suggestion (Bourke et al. 2001), that all significant occupation at the site had ceased by 4000/3900 cal BC. This end-date should now be amended to 3900/3800 cal BC. Follow-up statistical modelling sourced to published 14C data drawn from a wide selection of south Levantine Chalcolithic period sites (Bourke 2001; Burton and Levy 2001) raises the possibility that Chalcolithic period occupation had ceased at virtually all major centers by 3800/3700 cal BC. This, in turn, suggests that the new data bearing on the end-date for occupation at Teleilat Ghassul may reflect a more widespread horizon of abandonment in the southern Levant.

In this study, we applied a stepped-combustion approach to dating post-bomb lake sediment from north-central Mississippi. Samples were combusted at a low temperature (400 °) and then at 900 °. The CO2 was collected separately for both combustions and analyzed. The goal of this work was to develop a methodology to improve the accuracy of 14C dating of sediment by combusting at a lower temperature and reducing the amount of reworked carbon bound to clay minerals in the sample material. The 14C fraction modern results for the low and high temperature fractions of these sediments were compared with well-defined 137Cs determinations made on sediment taken from the same cores. Comparison of “bomb curves” for 14C and 137Cs indicate that low temperature combustion of sediment improved the accuracy of 14C dating of the sediment. However, fraction modern results for the low temperature fractions were depressed compared to atmospheric values for the same time frame, possibly the result of carbon mixing and the low sedimentation rate in the lake system.

The eruption of the volcano at Thera (Santorini) in the Aegean Sea undoubtedly had a profound influence on the civilizations of the surrounding region. The date of the eruption has been a subject of much controversy because it must be linked into the established and intricate archaeological phasings of both the prehistoric Aegean and the wider east Mediterranean. Radiocarbon dating of material from the volcanic destruction layer itself can provide some evidence for the date of the eruption, but because of the shape of the calibration curve for the relevant period, the value of such dates relies on there being no biases in the data sets. However, by dating the material from phases earlier and later than the eruption, some of the problems of the calibration data set can be circumvented and the chronology for the region can be resolved with more certainty.

In this paper, we draw together the evidence we have accumulated so far, including new data on the destruction layer itself and for the preceding cultural horizon at Thera, and from associated layers at Miletos in western Turkey. Using Bayesian models to synthesize the data and to identify outliers, we conclude from the most reliable 14C evidence (and using the INTCAL98 calibration data set) that the eruption of Thera occurred between 1663 and 1599 BC.

Air sample collections over the western Pacific have continued since 1992 as a part of Center for Global Environmental Research, National Institute for Environmental Studies (CGER-NIES) global environmental monitoring program. The air samples collected on the Japan-Australia transect made it possible to trace the seasonal and secular 14CO2 variations, as well as an increasing trend of greenhouse gases over the western Pacific. A subset of CO2 samples from latitudes of 10–15°N and 23–28°S were chosen for accelerator mass spectrometry (AMS) 14C analysis using a NIES-TERRA AMS with a 0.3–0.4% precision. These 14CO2 records in maritime air show seasonal variations superimposed on normal exponential decreasing trends with a time constant of about 16 yr. The Δ14C values in the Northern Hemisphere are lower those in the Southern Hemisphere by 3–4 during 1994–2002. The Northern Hemisphere record shows relatively high seasonality (2.3 ± 1.5) as compared with the Southern Hemisphere (1.3 ± 1.2). The maximum values of seasonal cycles appear in late autumn and early winter in the Northern and Southern Hemispheres, respectively. Oscillations of 1–10 yr over the western Pacific are found to correlate possibly with the El Niño/Southern Oscillation (ENSO) events.

New results of radiocarbon concentration in tree rings from the Kraków region covering a growth period of 20 yr have been analyzed, and the relationship between them and 14C concentrations in the atmospheric CO2 are described. This enabled assessment of the uptake period for pine trees at the regional climatic conditions. Both sets of data show lower 14C concentrations than reported for “clean air” at the reference station, indicating a remarkable input of “dead” CO2 of fossil fuel origin. Using data of carbon dioxide and 14C concentrations from Schauinsland, summer values of the fossil component (Cf) in carbon dioxide were calculated for the Kraków area. Fitting exponential and linear functions to experimental data, the exchange time was calculated, and expected future 14C concentration in the atmosphere was estimated.

This paper presents an updated radiocarbon chronology of the earliest pottery sites in the Old World. Ceramic production originated in the Late Glacial period in several regions of East Asia—the Japanese Islands, the Russian Far East, and southern China—at approximately the same time, about 13,700–13,300 BP (about 17,200–14,900 cal BP).

Given the non-monotonic form of the radiocarbon calibration curve, the precision of single 14C dates on the calendar timescale will always be limited. One way around this limitation is through comparison of time-series, which should exhibit the same irregular patterning as the calibration curve. This approach can be employed most directly in the case of wood samples with many years growth present (but not able to be dated by dendrochronology), where the tree-ring series of unknown date can be compared against the similarly constructed 14C calibration curve built from known-age wood. This process of curve-fitting has come to be called “wiggle-matching.”

In this paper, we look at the requirements for getting good precision by this method: sequence length, sampling frequency, and measurement precision. We also look at 3 case studies: one a piece of wood which has been independently dendrochronologically dated, and two others of unknown age relating to archaeological activity at Silchester, UK (Roman) and Miletos, Anatolia (relating to the volcanic eruption at Thera).

A chronological framework for the prehistoric cultural complexes of Sakhalin Island is presented based on 160 radiocarbon dates from 74 sites. The earliest 14C-dated site, Ogonki 5, corresponds to the Upper Paleolithic, about 19,500–17,800 BP. According to the 14C data, since about 8800 BP, there is a continuous sequence of Neolithic, Early Iron Age, and Medieval complexes. The Neolithic existed during approximately 8800–2800 BP. Transitional Neolithic-Early Iron Age complexes are dated to about 2800–2300 BP. The Early Iron Age may be dated to about 2500–1300 BP. The Middle Ages period is dated to approximately 1300–300 BP (VII–XVII centuries AD).

Annual tree rings from Thailand were analyzed by radiocarbon AMS for AD 1938–1954. The results showed no significant depletion in atmospheric 14C over Thailand during the pre-bomb period, even though the air mass to Thailand during the growing season of tree rings is transported over a potentially significant source of oceanic 14C-depleted CO2, out-gassing in the northern Indian Ocean. When compared with Washington and Chile for different periods from the 17th century to AD 1954, Thailand appears to have the characteristics of Southern Hemisphere 14C. This supports our previous finding that Thailand was strongly influenced by the entrainment of Southern Hemisphere air parcels in the southwest Asian monsoon (Hua et al. 2004). For Thailand, this effect is much stronger than the reduction of atmospheric 14C in association with CO2 out-gassing in the northern Indian Ocean.

Eleven woolly mammoth bone samples from Lugovskoe (central West Siberian Plain, Russia) were radiocarbon dated in 3 laboratories: Institute of Geology, Novosibirsk; Oxford University, Oxford; and Christian Albrechts University, Kiel. Each laboratory used its own protocol for collagen extraction. Parallel dating was carried out on 3 samples in Novosibirsk and Oxford. Two results are in good agreement. However, there is a major discrepancy between 2 dates obtained for the third sample. The dates obtained so far on the Lugovskoe mammoths range from about 18,250 BP to about 10,210 BP. The Lugovskoe results thus far confirm the possibility of woolly mammoth survival south of Arctic Siberia in the Late Glacial after about 12,000 BP, which has important implications for interpreting the process of mammoth extinction. The site has also produced the first reliable traces of human occupation from central Western Siberia at the Late Glacial, including unique direct evidence of mammoth hunting.

A kohitsugire is a paper fragment from an old manuscript written mainly in the Heian and Kamakura periods. Although they contain significant information for historical, literary, and paleographical study, because of their antique handwriting and description of historical incidents, there are many copies and counterfeits written several centuries later. In this study, radiocarbon ages of kohitsugire were measured by accelerator mass spectrometry (AMS). On the kohitsugire attributed to the famous calligraphists in the Kamakura period (Fujiwara no Sadaie and Prince Munetaka), 14C dating indicated that they were not genuine and should be excluded from the materials for study of the calligraphists. Calibrated 14C ages of the kohitsugire attributed to Fujiwara no Yukinari indicated the middle Heian period. This calligraphy was written on Tobikumogami paper, which has a billowing cloud pattern decorated with indigo-blue-dyed fiber. Although it was commonly accepted that the Tobikumogami is peculiar to the middle 11th to early 12th century, the results from 14C dating also suggested that the origin of the Tobikumogami would date back to the last of the 10th or the early 11th century, when Fujiwara no Yukinari flourished as a calligraphist. Calibrated 14C ages of the kohitsugire attributed to Nijo Tameuji and Reizei Tamesuke showed that they are fragments of old manuscripts describing lost tales and were written in the 13th–14th century. Consequently, 14C dating clarified the existence of ancient tales which had been unknown and indicated their worth as a material for the study of classical Japanese literature.

The abrupt millennial-scale changes associated with the Younger Dryas (YD) event (“chronozone”) near the dawn of the Holocene are at least hemispheric, if not global, in extent. Evidence for the YD cold excursion is abundant in Europe but fairly meager in central North America. We are engaged in an investigation of high-resolution environmental changes in mid-North America over several millennia (about 10,000 to 14,000 BP) during the Late Glacial–Early Holocene transition, including the YD interval. Several sites containing logs or stumps have been identified and we are in the process of initial sampling or re-sampling them for this project. Here, we report on a site in central Illinois containing a deposit of logs initially thought to be of YD age preserved in alluvial sands. The assemblage of wood represents hardwood (angiosperm) trees, and the ring-width characteristics are favorable to developing formal tree-ring chronologies. However, 4 new radiocarbon dates indicate deposition of wood may have taken place over at least 8000 14C yr (6000–14,000 BP). This complicates the effort to develop a single floating chronology of several hundred years at this site, but it may provide wood from a restricted region over a long period of time from which to develop a sequence of floating chronologies, the timing of deposition and preservation of which could be related to paleoclimatic events and conditions.

The Neolithic site of Schletz in Lower Austria comprises a fortified settlement from the end of the Linearbandkeramik (LBK) culture. Large numbers of human bones were found at the base of the fortification ditches, and many of the excavated bones and skulls showed evidence of trauma which most likely originates from violence. This remarkable deposit of human remains has been considered evidence for an abrupt end to the Early Neolithic settlement at Schletz. In order to investigate this interpretation, radiocarbon accelerator mass spectrometry (AMS) measurements of human bone samples from this site were performed at VERA. The χ2 test of the results from specimens with clearly identified lesions suggests that these may be contemporaneous. Further, it may be concluded that all individuals with evidence of trauma from Schletz were probably the victims of a single event: a massacre at the end of the LBK.

Similar evidence is found at Early Neolithic sites at Talheim and Herxheim in the western part of Germany. Analysis of the 14C ages of bones from both sites suggests that the Talheim event may have been coeval with the massacre of Schletz, whereas an event at Herxheim might have happened some time earlier. For Herxheim, the massacre theory is still under discussion, and a change in the burial rite is also considered as an alternative interpretation.

Two independent 14C data sets of 10 tree-ring samples from the longest master chronology of the Pazyryk cultural complex were obtained and wiggle-matched to the absolute timescale. The results show very good agreement, within 10–15 calendar yr. The Ulandryk-4 burial ground (mound 1) was dated to about 320–310 cal BC, and this is consistent with wiggle-matching of the Pazyryk burial ground date series.

The dating of the settlement of Iceland has been debated for many years. According to written sources (sagas) from the early 12th century, the first Norwegian settlers arrived in Iceland in AD 874. However, some 14C dates from the earliest archaeological sites in Iceland, invariably from samples of birch and other indigenous wood species, have yielded surprisingly old ages, older by 100–150 yr than the historical date, suggesting that the settlement took place in the 7th or 8th century. In this paper, we report 16 new 14C dates of pairs of barley grain and wood samples from an excavation in Reykjavík in 2001. The new results show that the wood samples tend to be older than the grain samples by up to about 100 yr. We argue that the barley grains give the true date (AD 890), whereas the wood dates are too old. The grain dates are in close agreement with the settlement year quoted in the written sources. In particular, our new data eliminate the need of any of the ad hoc theories introduced up to now to explain the suspiciously high 14C ages of wood samples from the settlement of Iceland, namely, 1) the island effect, 2) the volcanic or geothermal effect, or 3) that settlement actually took place significantly before the time recorded in the sagas.

We have measured the radiocarbon concentrations in single-yr tree rings of old wood by accelerated mass spectrometry (AMS) using a multicathode. The 14C concentrations of 10 single-yr tree rings were measured in 100 tree rings at intervals of 10. For each single-yr tree-ring sample, typically 80 measurements of the 14C concentrations were carried out using multicathodes. The sample standard deviations indicated that there are other fluctuations of typically 1.5%, in addition to the fluctuation of the Poisson counting statistics which is typically 3% for each measurement. The average 14C date of the tree rings was 22,130 ± 306 BP for all 624 data of single-yr tree-ring samples measured by the multicathodes. From the calibration data of Lake Suigetsu, the calendar dates of these 100 tree rings were located between 25,400 cal BP and 26,150 cal BP. The 14C dates changed between 21,979 BP and 22,272 BP, with an error of approximately 50 BP, corresponding to a precision of approximately 0.5%. There was a step with a change of approximately 144 BP for each 10 yr in the time profile.

Often it is not possible to date a sample of wood from the final growth ring of the tree from which it came. In these cases, an “old-wood offset” is apparent. A number of quantitative approaches for the assessment of this offset are available, dependent on the actual tree rings that have been dated. A range of examples are given, demonstrating how such radiocarbon measurements can be interpreted using additional information from archaeology and dendrochronology.

The largest volcanic crater on Easter Island in the South Pacific contains a lake 1 km in diameter with large floating mats of vegetation, mainly Scirpus californicus. A core taken through a mat near the center produced anomalous dates, with older dates above younger ones. The possibility that the mat had become inverted was considered, but palynological evidence refutes this idea because it shows a progressive upward decline of forest pollen, which is well known from other swamp cores on the island. A new series of radiocarbon dates made directly on pollen concentrates was obtained. These dates also produced inconsistencies, particularly when pollen concentrate ages were compared with 14C ages on plant fragments from the same depth. This series of 14C ages seems to indicate that both old and young organic components in the sediment are deposited contiguously and that the depositional history of these cores is more complex than previously known. Previous age determinations on bulk sediments from Easter Island, which also show anomalous dates, may be too simplistic. This paper provides a warning to other researchers dating sediments from Easter Island. We suggest that sample selection and dating procedures be carefully considered for these sediments.

This paper presents the variation of radiocarbon content in annual tree rings for the period AD 1413–1553, which includes the Spoerer Minimum period (AD 1415–1534). Since the variation of the production rate of 14C is strongly related to solar activity, the variation of 14C content in annual tree rings gives us information on the characteristics of variation of solar activity. We have studied solar activity during the grand solar minima, focusing especially on the stability of the 11-yr cycle. The minima are determined to have been almost free of sunspots. Our results, however, have revealed quite remarkably the existence of the 11-yr cycle for most of the time during the Spoerer Minimum. The 11-yr variation weakened around AD 1460–1510, suggesting that solar activity might have been strongly suppressed during these 50 yr.

A technique of accelerator mass spectrometry (AMS) has made it possible to directly measure radiocarbon ages of pottery by isolating organic materials sealed in the pottery when the pottery was formed. We analyzed the carbon contents and 14C ages for “black pottery” from the Philippines and “fiber pottery” from Japan using the relevant carbonaceous materials extracted from the pottery samples, i.e., adhered chaff or grass fibers that were incorporated in the pottery matrix, respectively. The carbon yield of the pottery sample varied largely depending on the pottery types, the preservation conditions, as well as the chemical pretreatment methods to purify carbonaceous materials for 14C dating. We will discuss criteria for sample selection of well-preserved pottery, and a modified method, instead of the standard alkali treatment, to obtain sufficient material for precise 14C dating.