The research aims to reconstruct the chronology of building the Southwest Church, Umm el-Jimal, Jordan by AMS radiocarbon dating organic inclusions uncovered from the mortars collected from the floor of the church, seat of the apse and the base of the north wall. It sheds light on the major aspects of mortar recipes at the time of their production. Samples were examined macroscopically with magnifying lenses and characterized using archaeometric techniques of optical microscopy and X-ray diffraction. The radiocarbon dates showed that 594–643 AD is the most probable age for flooring and plastering the church and 995–1154 AD is the earliest possible date for its final collapse. The preparatory layers of the church floor were laid on an older one, probably of a yard, and its north wall was raised on an older base, both most probably date to the late fifth–early sixth century AD. The production recipe of the mortars is made from a lime binder and inclusions mainly of organic (charcoal) and inorganic (quartz, grog, volcanics). The mortars have the same recipe regardless their bedding and jointing functions which remained unchanged during the building stages of church complex.

The Riga Radiocarbon Laboratory began its serial measurements in 1971. Radiocarbon activity is measured by solution scintillation counters. Benzol, obtained by acetylene trimerization on vanadium pentoxide activated silicagel, is used as 14C activity carrier. The dates refer to 1950 according to the 5568-year half-life of 14C. The statistical error is 1σ (Veksler, Putans & Savvaitov, 1971).

We present data here of samples from coastal regions of the USSR, which reflect their geologic-geomorphologic development (Veksler et al, 1975; Veksler, Putans & Stelle, 1977; Veksler & Prede, 1986).

In this study, we investigate the distribution of radiocarbon and uranium in the calcified opercula of Turbo sp. collected from Ryukyu region and Chiba, Japan, to explore the potential of U/Th dating using mollusks collected from the Japanese archipelago. We acquired high-resolution radiocarbon and uranium concentration measurements using single-stage accelerator mass spectrometry and laser ablation−inductively coupled plasma−mass spectrometry. Our results show that uranium in the opercula of modern Turbo sp. is unevenly distributed at concentrations 1000 times less than those in coral skeletons. Radiocarbon found in the calcified opercula samples record ambient seawater radiocarbon values as well as coral skeletons. Uranium in the calcified opercula of Holocene Turbo marmoratus were also unevenly distributed and concentrated within the opercula in a different manner than observed in modern samples, suggesting uranium exchange after death. Our results suggest variable uptake of uranium isotopes into mollusk shells and highlights the need for rigorous sample selection criteria when choosing mollusks species for U/Th dating around Japan.

The management of counting files, the calculation of radiocarbon age, and the creation and maintenance of databases for storage and retrieval of laboratory data are time-consuming and exacting tasks. These routine functions are essential to the successful operation of all 14C dating laboratories. However, since the number of 14C dating laboratories worldwide is rather limited, it is unlikely that a commercial software company will produce a program for use in 14C age calculation and associated data management. We have therefore developed Windows based software to meet some of these needs.

A summary of the chronology for the key paleontological and archaeological site of Volchia Griva in the southern part of the West Siberian Plain is presented. Currently, 42 reliable 14C values have been generated on animal bones (37 14C dates) and charcoal (5 14C dates). Three stratigraphic levels of animal bones are established. The 14C ages of the fossils are as follows: the upper level—ca. 10,620–12,520 BP; the middle level—ca. 13,700–17,800 BP; and the lower level—ca. 18,230–19,790 BP. The majority of animal fossils and artifacts are associated with the lower level. Based on the results obtained, we suggest that Upper Paleolithic people occupied the Volchia Griva site during the second part of the Last Glacial Maximum (LGM), ca. 18,200–19,800 BP, and perhaps occasionally afterwards. It is obvious that these humans were well adapted to the cold and dry climate of the LGM, as well as numerous other populations in Siberia south of 58°N. It is noteworthy that the youngest 14C values on woolly mammoth are of ca. 10,620–11,815 BP, and this makes the Volchia Griva one of the latest mammoth refugia in northern Eurasia outside of the Arctic.

Rýzmburk Castle is one of the largest and most important medieval castles in Bohemia, documented since 1250 AD. Its North tower is assumed to be built in 1260–1300 AD. To test this assumption, the surface layers of mortar were inspected for the presence of charcoals suitable for radiocarbon dating, and 10 charcoals were found. The charcoals probably originated from wood used for lime burning. The results of radiocarbon dating using accelerator mass spectrometry agree with the historical estimation. Single post-1287 sample indicates that the building date might be refined to 1287–1300 AD.

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.

Quantifying the marine radiocarbon reservoir effect, offsets (ΔR), and ΔR variability over time is critical to improving dating estimates of marine samples while also providing a proxy of water mass dynamics. In the northeastern Pacific, where no high-resolution time series of ΔR has yet been established, we sampled radiocarbon (14C) from exactly dated growth increments in a multicentennial chronology of the long-lived bivalve, Pacific geoduck (Paneopea generosa) at the Tree Nob site, coastal British Columbia, Canada. Samples were taken at approximately decadal time intervals from 1725 CE to 1920 CE and indicate average ΔR values of 256 ± 22 years (1σ) consistent with existing discrete estimates. Temporal variability in ΔR is small relative to analogous Atlantic records except for an unusually old-water event, 1802–1812. The correlation between ΔR and sea surface temperature (SST) reconstructed from geoduck increment width is weakly significant (r2 = .29, p = .03), indicating warm water is generally old, when the 1802–1812 interval is excluded. This interval contains the oldest (–2.1σ) anomaly, and that is coincident with the coldest (–2.7σ) anomalies of the temperature reconstruction. An additional 32 14C values spanning 1952–1980 were detrended using a northeastern Pacific bomb pulse curve. Significant positive correlations were identified between the detrended 14C data and annual El Niño Southern Oscillation (ENSO) and summer SST such that cooler conditions are associated with older water. Thus, 14C is generally relatively stable with weak, potentially inconsistent associations to climate variables, but capable of infrequent excursions as illustrated by the unusually cold, old-water 1802–1812 interval.

In 1979 when accelerator mass spectrometry was started in the Netherlands, Gove (1978) and Litherland (1980) demonstrated that a tandem accelerator is eminently suited for this work. Isotope ratios below 10−15 could be determined and applications were stimulated on numerous fields of research. 14C dating in particular would become an important application because smaller samples could be employed and more complex dating problems could be attacked. However, the 5% accuracy reached at that time had to be improved towards the 0.5% obtained with the conventional method of counting decays. Purser and Hanley (1978) pointed out that this high accuracy could be reached in facilities especially dedicated to dating. Rapid switching between measurements on different isotopes turned out to be crucial (Suter et al, 1981). We decided to proceed in two phases. In the first phase, the existing EN-tandem facility would be used as before and modified for the detection of 14C ions. From measurements with 14C ions from different samples, information would be obtained about the limitations of the existing facility. In the second phase, this information would be used to develop a facility in which accurate measurements of isotope ratios can be performed for elements throughout the periodic system. Conventional 14C dating will be extended in collaboration with the Isotope Physics Laboratory in Groningen. Also, applications with other elements will be studied. The improved facility is scheduled for operation in the spring of 1983.

I wish to point out some statistical errors in the uncertainty calculations for the radiocarbon age of the Vinland Map (Donahue et al. 2002). First, the authors state that the 14C measurements of samples with chemical treatments B, C, D, and E “… result in consistent radiocarbon ages”, and that “… two (of these analyses) are 1.5 sigma, and the others are one sigma or less, from the weighted average.” In fact, the overall scatter of the data show that it is improbable that these data are statistically coherent, largely because analysis J21C lies 2.1 sigma from the weighted mean.

The Eastern Chukotka is considered a unique permafrost region where massive ice bodies are widespread. However, the origin and age of these ice formations are often discussed. The age of the massive ice of Chukotka was established for the first time using AMS 14C dating. It was revealed that three massive ice bodies on the coast of Mechigmen Bay were formed at the end of the Late Pleistocene: a) near the Akkani site, 21,612 to 22,147 cal BP; b) near the Lavrentiya settlement, 27,553 cal BP; and c) near the Lavrentiya settlement, 22,193 cal BP. Stable isotope values in the studied massive ice vary in a rather wide range by about 10‰ for δ18O values (from –14.8‰ to –24.5‰) and about 75‰ for the δ2H values (from –116‰ to –191‰). The studied massive ice bodies are of intrasedimental genesis and formed epigenetically during the final stage of MIS2 (22–27 cal ka BP).

The following results represent measurements carried out since our 3rd date list was prepared. The entire CO2 purification technique (Radiocarbon, 1962, v. 4, p. 81–83) has been changed to “wet purification.” No measurements of C12/C13 ratios have been made.

To obtain scientific data regarding the chronology of archaeological structures, lime mortar radiocarbon dating has often demonstrated to be a decisive method. However, knowing the specific chemical-mineralogical characteristics of mortars can help when preparing samples or interpreting results. Among other issues, the dating of magnesian mortars can be particularly difficult because of the combined slaking, setting and hardening reactions of the calcium and magnesium phases, typical of these mortars. The formation of numerous mineralogical phases depending on reaction conditions adds further complexity to the dating method, which deserves to be studied with further detail. During the project “Mortar technology and construction history at Müstair Monastery” the first experiments in this regard had yielded encouraging results. An additional 4 samples from buildings with controversial chronology, thought to belong approximately to the 9th, 12th, and 15th centuries, were selected, prepared and radiocarbon dated. The data obtained were discussed by integrating preliminary petrographic characterization analyses of the mortars with archaeological information and excavation records. The results opened up new questions about the chronology of the Monastery, clarified the dating of some buildings and provided a better understanding of the potential and limitations of dating dolomitic mortars coming from archaeological context.

The potential 14C (carbon-14, radiocarbon) flux from disposal of 14C containing waste into air is compared with the natural 14C emanation rate from soil in order to put the 14C hazard potential from disposal of this waste in perspective with the 14C exposure from cosmogenic origin. Chemical corrosion of neutron irradiated metals, steel and Zircaloy, is bounded by diffusion of water through a thermodynamically stable metal-oxide layer and dissolution of this metal-oxide in a nuclear plant. Many countries process radioactive waste for disposal using cementitious materials, an acknowledged end-point management technique for this waste. The metal-oxides are also stable when these waste forms are embedded in cementitious materials. The 14C release rate from this Zircaloy at these alkaline and reducing conditions is comparable to the natural 14C emanation rate from soil into air. Neutron irradiated graphite and spent ion exchange resins are chemically inert and therefore other release mechanisms need to be assumed. Radiolytic corrosion is used to determine the 14C release rate from this graphite. Moreover, ion exchange—with ingressing anionic species that have a higher affinity than contained anionic 14C—is proposed as a release mechanism for these resins.

The Gaspereau Lake Reservoir Site Complex in Nova Scotia, Canada, yielded a large ceramic assemblage that permitted the first fine-grained analysis of ceramic change in the region at the Middle–Late Woodland Transition from ca. 1550 BP to ca. 1150 BP. The aim of this study was to refine the standard regional chronology first proposed by researchers J B Petersen and D Sanger. To do this, ceramics were directly dated using accelerator mass spectrometry (AMS), and the assemblage was categorized and analyzed to identify clusters of attributes. Ten AMS dates were acquired on carbonized food residue on the interiors of pottery and yielded the largest continuous ceramic sequence in the Maritime Provinces of Canada. This sequence was used to infer a change in manufacturing practices between the Middle (2150–1300 BP) and Late (1300–500 BP) Woodland periods and to propose five new subperiods between 1650 BP and 950 BP. Increasing incidence of coil breaks and temper percentage from the Middle to the Late Woodland were found to be chronologically sensitive. The analysis showed that, at Gaspereau Lake, a gradual shift from finely decorated and manufactured pottery to expediently made pottery suggests that pottery was made in larger numbers to support large-scale gatherings.

During the last two decades the radiocarbon (14C) dating of hydroxyapatite archaeological cremated bones has become standard practice. Various pretreatment procedures exist among different laboratories of which some include fixation of SO2 using “Sulfix” prior to CO2 reduction. Recently it was reported that the use of Sulfix may cause the resulting 14C age to be too old. Here we report on the use Sulfix at the Aarhus AMS Centre. Further, we report on an experiment designed to test alternatives for the use of Sulfix as a purification agent.

This article presents new radiocarbon ages for the lavas, pyroclastic flow, and lahar deposits that originated from the Fugendake and Mayuyama volcanoes of the Younger Unzen Volcano, SW Japan. Nine charcoal samples were collected from the lavas and pyroclastic flow deposits, and 17 soil samples from the underlying volcanic-related products. This data set, together with previously published ages (thermoluminescence, K-Ar, fission track, and 14C), yielded new information about the timing of Late Pleistocene eruptions and an improved understanding of the evolution of the Fugendake and Mayuyama volcanoes. Fugendake Volcano started to build within the scar of Myokendake around 29 cal ka BP, and its eruption products spread over the flank of Myokendake. The remarkable eruptions of Fugendake Volcano included the lava and pyroclastic flow deposits around 22, 17, 12, and 4.5 cal ka BP. Subsequent historical eruptions occurred in AD 1663, 1792, and 1991–1995. Developed on the eastern extension of Fugendake Volcano, Mayuyama Volcano was active during the building stage of Fugendake at 4.5 cal ka BP. This study also identified a pumice eruption at ∼10 ka and 2 volcanic-related lahar deposits around 1.6 and 0.7 ka, which need to be addressed in future research.

This list reports measurements made on archaeologic and geologic samples by our laboratory from June 1982 to December 1983. Results of measurements made during that period which lack review by submitters will be reported in a subsequent date list. Sample preparation techniques and benzene synthesis remain as described previously (R, 1982, v 24, p 344–351). For low organic samples, such as sediments, we now use a combustion tube assembly. These samples are burned under oxygen flow in a quartz tube. To absorb sulfur and break up nitrous compounds, we pass combustion gases through a 50% mixture of MnO2 and CuO wire heated to ca 500°C. The gas is then bubbled through a distilled water and KMnO4 solution to remove chlorides before being introduced into our standard dry ice and CO2 traps.