The SUERC Radiocarbon Dating Laboratory has recently replaced its spreadsheet-based record keeping with a new database program, custom designed to help laboratory staff manage the high throughput of nearly 5000 cathodes in the past year. The system can accept data from a variety of sources in addition to manual entry; experimental results can be uploaded from spreadsheets, while integration with graphitization lines means that graphite yields are automatically recorded. The system is able to pass 14C results directly to OxCal v 4 for calibration, with the resulting plots incorporated into the dating certificates issued to submitters. There are also benefits to submitters, with electronic sample submission both eliminating transcription errors and speeding up the logging-in process, which keeps turnaround times down. For bone samples, data on collagen yields are now stored electronically and are more readily obtainable from the laboratory. The new SUERC Radiocarbon Dating Laboratory database will make a significant contribution to maintaining the high quality of results produced by the laboratory, aiding staff in tracking sample progress, and monitoring quality assurance (QA) samples going through the laboratory, eliminating transcription errors, and making communication easier between laboratory staff and sample submitters.

To study the effect of ultrafiltration on the radiocarbon ages of relatively poorly preserved bones in Japan, we analyzed the 14C dates of high-molecular-weight (HMW) gelatin samples and compared them with those of other extracted organic fractions, unfiltered gelatin samples extracted from NaOH-treated or NaOH-untreated collagen, and XAD-purified hydrolysates of animal fossil bones (∼4600 BP; gelatin yield of 2–4%) from the Awazu underwater archaeological site, Shiga, Japan. NaOH-treated, unfiltered gelatins and XAD-purified hydrolysates showed statistically similar 14C ages to those of HMW gelatins. The 14C ages of the HMW gelatins were the oldest and similar to those of wood collected from the same layer as the bones, and the NaOH-treated, unfiltered gelatins gave 14C ages within the acceptable margins of error; therefore, ultrafiltration was effective for accurate 14C dating, while NaOH-treated gelatin without ultrafiltration was also sufficient to obtain accurate 14C dates on the animal bones. The 14C ages of human skeletons (∼750 BP; gelatin yield of 2–11%) from 5 individuals excavated from an archaeological site in Yuigahama, Kamakura, Japan, showed statistically the same 14C ages as NaOH-treated, unfiltered gelatins and HMW gelatins within the margins of error, although HMW gelatins were likely to give slightly older ages than unfiltered gelatin with a yield of less than ∼3%. These results indicate that unfiltered gelatins extracted from fossil bones of gelatin yield more than ∼3% can produce accurate 14C ages without the need for ultrafiltration. Ten bone fragments from 3 humans showed the same 14C ages for each individual, suggesting that any bone part from an individual can be used to obtain a representative age. The 14C ages of tooth enamels of 2 individuals were 35 and 70 yr older than their bone ages. Death dates obtained from these age gaps agreed with those determined by morphology.

135Cs with a half-life of T1/2=2.3×106 yr is an important nuclide in studies of the dispersal of nuclear material in the environment. Preliminary measurements using 133Cs as a proxy for the long-lived 135Cs, with accelerator mass spectrometry (AMS) have been developed at the China Institute of Atomic Energy (CIAE). In order to improve the sensitivity of 135Cs AMS measurement, a new conducting material, Fe powder, was used in the experiment. According to the present results, the background level that can be obtained with blanks was 135Ba/Cs~1.83×10–10 with the CIAE-AMS system. These measurements showed that the Fe was an inferior conducting medium because the interference of 135Ba in Fe powder is 10 times higher than that in Ag powder.

This list contains the results of measurements of 167 groundwater samples made between September 1979 and December 1982. An additional 175 samples were measured, but these were submitted without detailed information, such as sampling depth, well location, etc; therefore, they were excluded from the following list.

The study of the mechanisms of radiocarbon (14C) release from different types of radioactive waste in final disposal conditions (organic, inorganic species, liquid, or gaseous phase) is an important aspect for the definition of waste acceptance criteria in a repository. The goal of this work is to determine the behavior of activated stainless steel, under standard leaching tests performed at El Cabril laboratory, with the aim of determining the retention capacity of the activated stainless steel, and therefore to assess the treatment and the potential additional barriers necessary for the fulfillment of waste acceptance criteria relevant to the El Cabril surface repository, Spain.

This list comprises age measurements carried out from 1973 to 1974 In dating the samples reported here as well as in calculating their ages, the same equipment and methods were used as previously described (R, 19/3, v 15, p 586–591; 1974, v 16, p 388–394).

In 2004, the courtyard of Ca' Foscari University, Venice, was excavated in advance of building work, revealing an unbroken sequence of archaeological deposits. The earliest layers consisted of redeposited natural sediment, packed into wattle structures, a system of land reclamation first described by Cassiodorus in AD 537–8, and now known from several other sites in the city. The ground level was built up and extended several times with successive wattle structures, before the eventual construction of a stone waterfront. We have used Bayesian modeling of dendrochronological, radiocarbon, and stratigraphic dating evidence to obtain a precise chronology for the earliest phases of occupation, and to compare it to the chronology of land reclamation at similar sites elsewhere in Venice.

Measurements have continued with the same proportional counter system, pretreatment procedure, methane preparation and measurement, and calculation, as described previously (R, 1970, v 12, p 298-318). Uncertainties quoted are single standard deviations originating from standard, sample, background counting rates and half-life. No 13C/12C ratios were measured.

At the Ninth International Radiocarbon Conference a paper was presented concerning possible short-term 14C variations in 4000-year-old red deer antlers (Cervus elaphus) found in Neolithic flint mines in Norfolk, England (Burleigh and Hewson, 1980). It was argued, on archaeologic grounds, that the true age of the samples varied by a few years at most. Their radiocarbon ages, however, varied by a considerably greater amount than could be explained by the errors in the measurements. Duplication of the measurements confirmed this unexpected variation.

Farmer and Baxter (1972) claimed a significant correlation of atmospheric 14C levels in the northern hemisphere with sunspot number based on radiocarbon assay of single tree rings for the period 1829 to 1865. In contrast, Stuiver (1978) stated that a series of single-year Douglas Fir measurements did not show a statistically significant periodicity.

This paper reports measurements made on a series of single-year dendrochronologic samples of approximately the same age as the red deer antlers, which have been carried out at the British Museum Research Laboratory. The results show that the variation in 14C between rings is not statistically significant; some other explanation must be sought for the anomalous antler measurements.

The tuning of plateaus in glacial and deglacial planktic radiocarbon records to pertinent structures in the atmospheric 14C record of Lake Suigetsu results in both a record of surface water reservoir ages and a centennial-scale absolute age model. However, the atmospheric origin of planktic 14C plateaus may be questioned. Alternatively, plateaus may result from short pulses of increased hemipelagic sediment deposition, which challenges the technique of 14C plateau tuning. To test the two rationales for the interval 23–12 cal ka, we calculated hypothetical sedimentation rates for all 14C plateaus identified in five Atlantic sediment cores assuming sediment pulses that either span 10, 100, 200, or 300 yr each. These rates were compared to rates derived by 14C plateau tuning that assumes an atmospheric origin of the plateaus. In each plateau suite, our hypothetical sedimentation rates result in at least one or two cases in extreme values that exceed the rates reported for short-lasting pulses of sediment deposition in contourites by a factor of 50 and therefore appear unrealistic. Moreover, they result in entire suites of plateau structures that incidentally appear closely aligned to the pattern of atmospheric 14C plateau suites rather than to any pulses of climate-controlled sediment discharge.

Leather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.

Atmospheric CO2 samples have been collected by the Trondheim Radiocarbon Laboratory since the 1960s. The remaining material from the measurements has been precipitated as CaCO3 and stored in glass containers. We investigated some of the stored samples to assess whether the material could still be used for remeasurements of atmospheric radiocarbon (14C) content, or if it has been contaminated during the years of storage. We attempted different methods to clean the carbonate and release the CO2 for new measurements. The results indicate that the older samples before 1970 show a significant change in 14C content compared to the original measurements, and that our cleaning methods have only little effect. Later samples from the 1970s, which were archived in glass containers with a different lid, show a lower contamination that, however, still leads to an added uncertainty of several pMC and makes these samples unreliable.

The Radiocarbon Laboratory at the University of Barcelona began its serial measurements in 1985. The following list contains dates obtained between 1985 and 1987. Both archaeological and geological samples were dated.

The measurement technique we use is liquid scintillation counting of benzene. A previous paper (Mestres, García & Rauret 1991) describes sample pretreatment, synthesis and counting protocols and equipment.

This paper presents new results of radiocarbon (14C) ages from archaeological sites in northern Igboland. The study was designed to shed more light on early human occupation and activities in the study area based on sediments from cave and iron-smelting sites. The approach consisted of ethnographic, archaeological, palynological, and slag analyses; these were complemented with 14C dates. The technology adopted as well as the paleoenvironmental conditions that prevailed during the period of human settlement in both sites was revealed. These data, complemented by 14C dates, highlight the human behavioral and subsistence patterns within the region and are comparable to those from similar sites in southeastern Nigeria.