Accelerator mass spectrometry (AMS) radiocarbon dating and paleoecological analysis of slope deposits at Mt Raizan provided seven 14C dates indicating that landslides occurred in that area at 6.0 to 6.3 cal ka BP and 6.5 cal ka BP. Plant macrofossils, pollen grains, and spores point to a mixed forest at that time, consisting of conifers and broad-leaved trees. On the other hand, insect fossil indicates slightly colder climate than that of the flora. This difference may be attributed to varied sensitivities of each proxy to climatic changes.

It is common practice to estimate the age of undated material extracted from a sediment core from radiocarbon or other radiometric dates of samples taken above and below the extracted material. This paper presents a simple expression for the variance of this estimated age. This variance accounts for both 14C dating error and error due to bioturbation.

In 1981, the first 14C and Archaeology Symposium was organized because it was felt necessary to have a symposium that focused on the specific problems related to the use of 14C dating in archaeology. The dating method has been constantly changing and approving itself technically as well as in the application of the method. The relationship between the archaeologists and the 14C dating laboratories has, however, never been straightforward. For a lot of 14C laboratories, archaeology was not their core business. For archaeologists, the main problem arose from an insufficient knowledge of natural sciences. The last decennia, however, 14C and archaeology are growing towards one another. One of the reasons might be the introduction of small exclusively 14C-dedicated machines and the availability of fully automatic graphitization lines.

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.

Atmospheric 14C concentrations vary with time and latitude. These variations, measured directly on atmospheric samples, or in independently-dated organic material such as tree rings, supply data essential for the calibration of dynamic models of the global carbon cycle. Short variations in the production rate of atmospheric 14C are strongly attenuated in the relatively large atmospheric CO2 reservoir. In-situ production of 14C should be negligible for ages up to 80 ka bp. Background problems in AMS dating are more likely attributable to contamination of very small samples.

Construction of a new science complex in Osong, Cheongwon-gun, Korea, has allowed the investigation of 14 different Paleolithic localities, excavated during 2005–2007. Here, we investigated localities 1 and 12 of the Mansuri Paleolithic site to obtain chronological information using radiocarbon dating. The soil deposition rates varied from 0.09 to 0.15 mm/yr over the period ranging from 33 to 31 kyr BP for locality 1. Locality 12 samples were more recent, <10 ka, and have similar accumulation rates, averaging 0.11 mm/yr. The soil ages of locality 12 were found to be younger than 10 kyr BP. Results for both soil and organic materials at this locality gave much younger ages at shallower depths than the ages expected by the Korean Paleolithic cultural history for this region. Therefore, these more recent deposits may not be associated with the cultural layers and are interpreted to have been hydrologically modified following emplacement. 14C dates of the soil and organic materials at locality 12 confirm that there is evidence for multiple human occupations throughout the last 9 kyr BP.

A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of the same age measured by Stuiver and Pearson (1993) for calibration purposes. The average difference was found to be 54 ± 72 14C yr. The results further indicate that the actual standard deviation is only 7% higher than that quoted by the laboratory. The investigation has shown a long-term stability of laboratory accuracy with no systematic laboratory variations either with respect to sample age or to the time of measurement from 1971 to 1993.

When used with 14C records, an accurate reconstruction of the 13C/12C changes of atmospheric CO2 may be a key constraint to determining the historic activity of the biosphere as CO2 source or sink. We recently detailed the derivation of an atmospheric δ13C record for 1930–1979 from Arizona juniper tree rings (Leavitt and Long, 1983). Each tree was close to a weather station, allowing us to account for the effects of climate on the tree-ring δ13C records. The resulting atmospheric δ13C trend shows an overall decrease of ca 1.3‰, but instead of decreasing exponentially over the whole 50-year period, the best-fit curve decreases exponentially to ca 1960 and then flattens out. The drop from 1956 to 1978 was ca 0.55‰, still very similar to the measured atmospheric drop over that period of 0.65 ± 0.13‰ (Keeling, Mook, and Tans, 1979).

Radiocarbon has been applied as a tracer to study carbon dynamics in different types of tropical soils, under paddy and non-paddy management on Java, Indonesia. The 14C concentrations were measured in samples of total organic carbon as well as in alkali-soluble humic acids, insoluble humin, and plant remains (roots, seeds, leaves) obtained from three sites with Andosols, Alisols, and Vertisols at different altitudes. In addition, the abundance and distribution of plant macrofossils in the soil column and organic δ13C values were determined. The results obtained so far are compared with those from a chronosequence of Cambisols in China. They indicate the input of fresh plant materials into the subsoil directly via roots and/or by soil cracks and bioturbation of aboveground litter. The total organic C and 14C concentrations show the usual decrease with increasing depth in paddy and non-paddy soils, reflecting the influence of direct input as well as the downward redistribution of organic material as particulates or dissolved organic carbon (DOC) depending on soil type (pedogenesis, plough-pan formation, drying cracks), crop type and management, and climatic factors. A disturbance of the Andosol around 0.4 m depth and a change in profile properties around 0.63 m in the Alisol limit the general conclusions.

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.

The present research is focused on the dating of the Oglakhty burial ground, the key site of stage I of the Tashtyk culture. Despite the numerous well-preserved burials of that type investigated at the Oglakhty complexes, their chronological position has remained unclear. From the early 20th century until the present, 2 different time periods had been identified for the Tashtyk burials: (1) from the 1st century BC until the 1st century AD and (2) from the 1st until the 2nd century AD. New data obtained in the 1990s suggested a different age for Tashtyk burials, namely the 3rd–4th centuries AD. This considerable shift in chronology needed to be checked with independent data. The chronological position of one of the Oglakhty burials, tomb 4, has been investigated with the use of wiggle-matching, applied to wooden logs used in the construction of tomb 4. The resulting dates for this burial strongly suggest its age as being limited to the 3rd–4th centuries AD, which is corroborated by the archaeological dates of the imported artifacts found in the grave and which is in agreement with the chronological position of the Oglakhty site, as proposed by previous investigations.

This list contains the results of 14C determinations obtained at the laboratory in 1986 and 1987. δ13C was measured by the British Museum Research Laboratory or the Free University of Brussels: *δ13C is estimated (Stuiver & Polach, 1977).

Two recently published sets of radiocarbon dates, one from Mesopotamia and one from Anatolia, gave anomalous results. On the basis of historical analysis, both sets were expected to date to the 7th century BC. However, the 14C results were more than a century older than this. We tested samples from an Egyptian mummy, also historically dated to the 7th century BC, to see if such discrepancies were more widespread at this time. We did not find evidence of such a problem, but the results do provide insights into the reuse of old wood in ancient Egyptian coffins. We include publication of an earlier set of dates from the same mummy and coffin set.