This list includes dates of geologic samples measured using a single-channel liquid scintillation 14C counter at the Geochemical and Statistical Laboratory, Tartu, Estonian SSR. Our modern standard is made of benzene enriched in 14C and its activity is checked with NBS oxalic acid standard sample. Dates are given in conventional radiocarbon years, based on the Libby half-life of 5570 ± 30 yr. AD 1950 is the reference year. Errors refer only to 1σ standard deviation calculated from count rates involved.

Presented below are dates from some important archaeologic and Quaternary sites. All dates are based on τ ½ = 5568 yr; to convert the radiocarbon dates for archaeologic samples into ad/bc scale, 1950 has been used as base as per the resolution passed at the Ninth International Radiocarbon Conference, San Diego, 1976. The dates are not corrected for 13C fractionation. All the dates older than 10,000 yr have been given with 2σ errors. Due to uncertainty about the contribution of the biogenic carbon in caliche (CaCO3) samples, the dates represent apparent and not true ages.

In 2015 a dispute arose between an electricity company (EC) and smallholder of a teak plantation when the EC felled 80 trees (without consent of the owner) in a linear transect under a rural power-line-corridor (PLC), fragmenting the teak stand in two portions. The EC stated that there were no planted trees in the area when the PLC was established in 2008. The owner asserted he planted the stand in 2006 so in 2008 the company should have seen the planted trees. We used the bomb radiocarbon (14C) signal of three felled trees and dendrochronological dating of five trees, three felled by the EC and two felled by us in 2016, to do this study to determine the age. We found that the first growth rings were dated to 2005 both in the trees felled by the EC in 2015 and felled by us in 2016, one year before that reported by the owner (2006). This year corresponds to the wood present in the cuttings during the stand’s planting year. These facts are in agreement with the owner’s testimony. The plantation was 10 years old in 2015.

In this work, we present the results of radiocarbon (14C) dating of three historically important objects related to the period of the reign of the Ottoman Empire in Europe. The following objects from the museum collection of the Franciscan Monastery in Fojnica, Bosnia and Herzegovina were 14C dated: (1) paper from the Ahdname (Fojnička ahdnama); (2) textile of the mantel of Fra Anđeo Zvizdović; and (3) paper from the Fojnica Armorial (Fojnički grbovnik). It was assumed that the Ahdname was issued in AD 1463 by the Ottoman Sultan Mehmed II to the Catholic monks and that the Mantel had belonged to Fra Anđeo Zvizdović, who received the Ahdname. The Fojnica Armorial is an important source of the classical heraldry of the Balkans Peninsula, with various estimates of the age. The 14C calibrated ages of the Ahdname are as follows: lower part, cal AD 1430–1465, upper part, cal AD 1665–1808, proving that only the lower part of the Ahdname was original. The 14C calibrated age of the textile from the outer layer of the Mantel is cal AD 1492–1641, somewhat younger than expected, and inner lining even younger, cal AD 1652–1805. Good coincidence between the calibrated age span of the renewed part of the Ahdname and the lining material of the Mantel can suggest that both objects had been renewed around the same time. Two samples of the Fojnica Armorial were dated: thick paper, cal AD 1631–1667 and thin paper, cal AD 1809–1926, showing that the Armorial had been compiled during different periods.

This paper presents radiocarbon (14C) dating of Scythian period sites discovered in Northern Altai, Russia, in the 1990s, including large, unlooted barrow cemeteries in the Manzherok region. The results indicate that barrows attributed to the Karakoba culture may represent a long time span from the beginning of the 9th century BC until the beginning of 1st century BC, while those linked with the North Pazyryk culture generally keep within the Scythian period: from the beginning of the 5th century BC to the late 1st century AD. 14C analysis has confirmed the viability of traditional archaeological dating and the contemporaneity of barrows belonging to various cultural traditions (North Pazyryk, Karakoba), and also allowed correlating the horizons of burials to the seismic phenomena observed at the site.

Using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS), radiocarbon concentrations were measured for wine from 8 wineries located in 7 countries in the Northern and Southern hemispheres. The 14C concentrations of ethanol and residual materials in the wine were correlated (correlation coefficient 0.82). The δ14C measurements of wine samples from the mid-latitudes in the Northern Hemisphere were approximately 1l% lower than the extrapolations from Schauinsland data, suggesting a local fossil fuel effect. δ14C measurements from the wine samples from the Southern Hemisphere were higher than those from the Northern Hemisphere. The offsets of the 4 wine δ14C measurements were significant, with values between approximately 8% and 15%. Because the harvest years of the mixed grapes were estimated to be 7–12 yr older than their vintage years, this leads to a caveat when determining the 14C concentrations of the year using the wine vintage.

Accelerator systems designed for a wide variety of ion beam analysis (IBA) applications usually have a multitude of beamline components and long beam lines. In the use of these systems, beam optimization is especially important for attaining high-precision accelerator mass spectrometry (AMS) results. The optimization involves multiple parameters, dependencies between parameters, and multiple optimization targets. To improve the repeatability and reliability of AMS results, we have developed a profiling program for automatic beam optimization. In our implementation, the accelerator control parameters, measured beam currents, and AMS detector count rates are all stored in a real-time database. The profiling routine can scan any accelerator parameter and fetch from the database the profile of any measured quantity as a function of the parameter. The routine is usually used to scan over roughly 20 essential parameters of the system and setting them to the optimum values. Automatic optimization is fast, easy to use, robust to noise, and gives reproducible results. In addition, the graphical output in the form of current and count rate profiles is highly informative. Automatic optimization together with other improvements to the AMS setup have enabled us to push the precision of the system to better than 0.2%.

Plasma oxidation for 14C sampling utilizes low-pressure (133 Pa), low-energy (<50 W), and low- temperature (<50°C) Ar- and O2-plasmas generating CO2 for AMS dating. O2-plasmas on empty chambers remove organic contamination. When clean, a new specimen is inserted and Ar-plasmas dislodge adsorbed atmospheric CO2 from surfaces. Finally, O2-plasmas oxidize organic materials to CO2 for AMS analysis. During some Ar-plasmas we observed anomalous pressure increases and unexpectedly high CO2. Residual gas analysis detected water, hydrogen and oxygen species with Ar and CO2 indicating water plasmas that produced excited oxygen species that prematurely oxidized specimen organic matter. Evolution of excess CO2 during Ar cleaning compromises the ability to affirm that atmospheric CO2 was removed. Standards, TIRI Belfast Pine and VIRI I Whalebone, were dated to determine whether water-induced oxidation was a confounding influence in dating. TIRI wood was sampled twice, once a water-soaked specimen in an Ar plasma and once with water-vapor-plasma only. The TIRI dates agreed with six earlier dates on usual specimens. A colloidal extract from VIRI I whale bone was also sampled and dated twice using both water–plasma oxidation in an Ar-plasma and in an O2-plasma. Dating agreement suggests that water plasmas do not pose undue risks of contamination.

The authors have developed an active absorption system combining a molecular sieve with a pressure gradient as a way to overcome the shortcomings of the phosphoric acid solution displacement method. Taking advantage of the pressure gradient produced between the inside and outside of a bottle, as water moves through it, CO2 in the atmosphere can actively be absorbed onto a molecular sieve in its pathway. A comparative study showed that the technique was in agreement with the phosphoric acid displacement method, within error. We applied the new method to collect not only atmospheric CO2 samples, but also CO2 samples from soil respiration to verify its utility. Simple yet practical, our method is well suited to extended collection times in a variety of environments, and capable of providing relatively large amounts of carbon for high-precision accelerator mass spectrometry (AMS) 14C analyses of atmospheric samples.

A radiocarbon (14C) dating technique with accelerator mass spectrometry (AMS) was applied to estimate the year of death and the year of birth of unidentified human remains. Because many of the samples have been preserved in formaldehyde, it was necessary to evaluate the influence of formaldehyde on carbon ages. Samples intentionally preserved in formaldehyde during the known period were measured, and their Δ14C values were compared with results obtained from fresh samples. The influence of formaldehyde on soft tissue was 14 times larger than that on cortical bone. Unfortunately, an effective method for removing the influence of formaldehyde has not yet been found. 14C ages could be obtained only from the samples not preserved in formaldehyde. The years of birth were determined by the ages of the dentin samples, while the years of death were determined by the ages of the bone and soft tissue samples. Multiple sampling from a body provides an advantage in determination of one of two possible ages of a sample obtained using the bomb peak. Victims of the Korean War were ascertained by the year of death. The year of death and the age at death of unidentified bodies were also determined for forensic investigation.

As one of the most extensive prehistoric entities of western Iran, Dalma culture belonging to the Zagros Chalcolithic, flourished in vast areas of the Central Zagros and Northwest Region of the country. This culture is defined essentially by its characteristic ceramic assemblages that show a marked uniformity in terms of technology, vessel forms, and painted designs throughout its territory. One of the main issues regarding this culture is its chronology, which was largely based on comparative studies, a few radiocarbon (14C) dates analyzed in the 1960s–1970s, or a few confusing thermoluminescence dates. In this paper, a series of 15 charcoal samples from a recent salvage excavation at Nad Ali Beig, a single-period site dated to Dalma period, is presented that provide the first reliable absolute dates for a part of the Middle Chalcolithic period of the Central Zagros region. Based on these new dates we may suggest that Dalma culture flourished between ca. 5200/5100–4600 BCE. Furthermore, based on these dates it is now possible to determine the order of appearance of different types of the Dalma culture ceramic assemblage, including the Ubaid-related painted buff ceramics.

The 14C age of charcoal and wood from Lebanon and central Europe is compared partly with the dendrochronologically determined age of the samples and partly with the archaeologically expected value. While the dendrologic values approximately confirm the correction curve of Ralph, Michael, and Han (1973), charcoal of burned layers seemes to be generally 2 to 3 centuries older than expected from contemporary archaeologically retrieved materials.

The results of a short program of landscape, buildings and materials analysis undertaken at Achanduin Castle, Lismore, Scotland (NM 8043 3927) are presented from the pilot phase of the Scottish Medieval Castles & Chapels C14 Project (SMCCCP). The study presents the first independent chronological evidence relating to the construction of this important medieval building, by radiocarbon analysis of a limited assemblage of Mortar-Entrapped Relict Limekiln Fuel (MERLF) fragments. Informed by a wider investigation of structural phasing and sample taphonomy, these measurements are constrained within a series of different Bayesian models, to generate a range of comparative estimates for the building’s constructional chronology. The precision with which the construction of this building can now be dated, from other evidence associated with the site, makes the Achanduin Castle study a useful point of reference for wider materials research.

The following list comprises selected measurements obtained by counting methane at 3 atm pressure in a 0.6 L stainless steel counter. Sample preparation, counting procedure, and calculation method are described in previous lists. Dates are reported in terms of the Libby half-life. The quoted errors are the experimental standard deviations including uncertainty on samples and standards.

For determining age scintillation variant was used. Measurement of a large quantity of benzol [benzene] permitted reaching a limit of 62,000 yr without isotope enrichment. Precautions against contamination of the samples with contemporary carbon and tritium were taken in laboratory handling. Dating began only after it had been established that contamination had not taken place during chemical treatment. Benzol which displayed no radioactivity was synthesized from anthracite. Special measures were taken to remove humic acids from the sample by boiling the powdered sample for three days with three fresh lots of 2% solution of NaOH (Arslanov et al., 1966a, p. 134).

The Committee on Missing Persons in Cyprus (CMP) is a bicommunal committee with the mandate to locate and identify the skeletal remains of 2002 persons who were reported missing during the inter-communal fighting of 1963–64, as well as the events of July and August 1974. During the periods of conflict, several archaeological sites and old cemeteries were used as primary burial sites, among several other types of burials, as they were easily accessed by the persons involved in the interment and little effort was needed to conceal the bodies. The relatively large post-mortem interval and the generally poor post-mortem preservation of the skeletal remains poses an additional challenge in the forensic examination process and the identification of the remains, particularly in the absence of a context or other associated artifacts/evidence. Between 2016 and 2020, the CMP has been collaborating with CEDAD to clarify the relevancy of several cases by using radiocarbon dating. The CMP submitted 139 cases to CEDAD out of which 112 were determined as not linked to the 1963–64 and 1974 events and then not relevant for the CMP project. For the remaining samples radiocarbon dating was used to determine death age.

In this paper we present data from the measurements of carbon isotopes (Δ14C and δ13C) from α-cellulose extracted from pine tree-rings. The samples were collected in four forests located in the most industrialized part of Poland, where coal mining and coal-based energy are an important branch of industry. The investigated period of time (1975–2012) covers the period of development in coal mining and other industry sectors. Stable isotope composition has been determined with using IRMS and radiocarbon concentration was determinate by AMS.

Dissolved inorganic carbon (DIC) in ocean water is a major sink of fossil fuel derived CO2. Carbon isotopes in DIC serve as tracers for oceanic water masses, biogeochemical processes, and air-sea gas exchange. We present a timeseries of surface DIC δ13C and Δ14C values from 2011 to 2022 from Newport Beach, California. This is a continuation of previous timeseries (Hinger et al. 2010; Santos et al. 2011) that together provide an 18-year record. These data show that DIC Δ14C values have declined by 42‰ and that DIC δ13C values have declined by 0.4‰ since 2004. By 2020, DIC Δ14C values were within analytical error of nearby clean atmospheric CO2 Δ14C values. These long-term trends are likely the result of significant fossil fuel derived CO2 in surface DIC from air-sea gas exchange. Seasonally, Δ14C values varied by 3.4‰ between 2011 and 2022, where seasonal δ13C values varied by 0.7‰. The seasonal variation in Δ14C values is likely driven by variations in upwelling, surface eddies, and mixed layer depth. The variation in δ13C values appears to be driven by isotopic fractionation from marine primary producers. The DIC δ13C and Δ14C values record the influence of the drought that began in 2012, and a major upwelling event in 2016.