In a wave-dominated coast, most of the Jacarepaguá coastal plain is occupied by buildings. During a new construction in this region at Barra da Tijuca, the subsurface area was excavated, exposing its quartzose sand nature, with a high mollusk shell concentration and in situ echinoderms at –10 m depth. The possibility to access this area encouraged us to investigate the evolution of the coastal plain. A 7.84-m-long core was recovered by percussion drilling. Stratigraphic, grain size, and geochemical analysis were undertaken. Three carbonate samples were dated by radiocarbon accelerator mass spectrometry (14C AMS). The revised sea-level variation curve revealed that the last postglacial marine transgression reached the present mean sea-level at 7945–7500 cal BP. The sandy deposit bottom was an ancient shoreface, with in situ echinoderms buried at 7770–7540 cal BP by the Pleistocene inner barrier reworking due to the last marine transgression. The Holocene outer barrier-lagoon and its flood tidal delta were formed from 5440–5070 cal BP. Mid-Holocene marine regression allowed the outer barrier progradation and the lagoon shallowing/infill. This paper confirms prior models proposed by other researchers for the Rio de Janeiro central coast and shows its similarity with the New South Wales coast, Australia.

Radiocarbon ages of single-year tree rings were measured for Kaminoyama wood samples using accelerator mass spectrometry (AMS) in 2 Japanese facilities, MALT and JAEA, in order to investigate the periodic variation of 14C concentrations relating to the 11-yr solar cycle near 26,000 yr BP. Eight sequential measurements of 14C ages were carried out for a set of 13 alternate single-year tree rings covering 26 yr. Averages of the 5 data sets in MALT and 3 data sets in JAEA were 22,146 ± 50 and 22,407 ± 58 14C yr BP, respectively, indicating an offset of 260 ± 77 14C yr. Multiple sequential measurements are advantageous for evaluating offsets. The standard deviation of the residuals of 14C ages from the averages in each data set was 118 14C yr, in contrast to that of 234 14C yr for the combined data sets due to an elimination effect in the offsets. The profiles of weighted mean values for the residuals of 14C ages showed similar enhancements with a width of ∼12 yr for measurements in the 2 facilities. This indicates the reproducibility of the multiple sequential measurements. In the profile for the combined 8 data sets, the 14C enhancement was 73 ± 36 14C yr from the average.

The “C14” data base, designed and implemented at the University of Arizona Radiocarbon Dating Laboratory, uses Q&A, an artificial intelligence data file management program. The data entered into this data base are easily retrievable and exportable for submission to RADIOCARBON, and to the International Radiocarbon Data Base (IRDB). The use of artificial intelligence allows both novice and experienced computer operators to search and retrieve data with few key strokes and normal English sentences.

This paper is a list of the first results of age determinations made at the Centre de Recherches Radiogéologiques de Nancy (CRR). The Center is the result of a convention between the Commissariat à l'Energie Atomique (CEA) and the University of Nancy. It is part of a group of research laboratories of Earth Sciences headed by Prof. M. Roubault.

Organic matter in the cultural layer of the ancient settlement Pesochnoe-1 near Lake Nero (NE of Moscow) yields reliable radiocarbon dates. The reason for this is the high concentrations of calcium and phosphorus in the cultural layer, especially in calcined bones. Several cultural epochs are distinguished in the cultural layer consisting of more or less homogeneous habitation deposits colored with humic susbstances. Artifacts of the Ljalovo culture are found in the lower part of the cultural layer; above these, artifacts of the Volosovo culture are present, and the upper part of the cultural layer corresponds to the Textile Ceramics culture. The 14C dates for humic substances in the layers show a good chronological stratification and correspond to known ages of these cultural stages. The 14C dates for the Ljalovo cultural layer cover 5600–5100 BP (4430–3900 cal BC), and dates for the Volosovo cultural layer span 4400–4200 BP (3000–2840 cal BC). Most dates from the upper part of the cultural layer correspond to the chronological interval of the Textile Ceramics culture and range from 3700 to 3200 BP (2100–1460 cal BC). More precise 14C dates were obtained for humic substances from archaeological objects in the upper cultural layer (hearths, fillings of pottery vessels, etc.): 3900–3500 BP (2100–1800 cal BC).

The following list of dates is of archaeologic samples submitted in 1971–2, using the counting equipment described in R, 1971, v 13, p 468. Ages are quoted with a 1σ counting error which includes statistical variation of the sample, background, and standard count. The reference year is ad 1950 and 0.95% NBS oxalic acid for 14C dating is the standard. The half-life used is 5570 years.

The accelerator mass spectrometry facility at Seoul National University (SNU-AMS) began functioning in December 1998 and was first reported at the Vienna AMS conference in October 1999 and at the 17th International Radiocarbon Conference in Israel in June 2000. At the Vienna conference, we reported our accelerator system (Kim et al. 2000) and details of the basic sample preparation system (Lee et al. 2000), such as the combustion line to produce CO2; the catalytic reduction line for the graphitization of CO2; and the pretreatment procedures for wood, charcoal, and peat samples. The recent progress of the AMS facility (Kim et al. 2001) and the extension of the sample pretreatment system to iron and bone samples were reported at the 17th International Radiocarbon Conference (Cheoun et al. 2001). In the meantime, extensive testing of accuracy and reproducibility has been carried out, and ∼1000 unknown archaeological and geological samples have been measured every year. In this report, the archaeological, geological, and environmental data carried out in 1999 are presented in terms of yr BP.

The following list includes samples dated in 1973. Benzene is used as the carrier of natural 14C activity as previously described (Punning et al, 1973). We used both 1-channel and 2-channel scintillation devices. The detector shield comprises 10cm lead. Around the detector we put 16 Geiger-Mueller type counters in anticoincidence circuit with output signals from detector. It decreased the average background ca 20 to 40%.

We present a comparative study on a 700-yr sequence of dendrochronologically ordered tree-rings of Pinus cembra originating from Eastern Carpathians for the period AD 1009–1709. This period covers the solar minima of the Little Ice Age. The aim of this study was to assess the accuracy of our radiocarbon (14C) determinations interpreted on the IntCal13 calibration data and to observe any apparent offsets. The 14C measurements on single and double tree-rings were “wiggle-matched” to secure the dendrochronology cross-matching of all the Pinus cembra wood pieces. The results showed a very good agreement between the age datasets for four out of five wood trunks. However, for one of them a new cross-matching was performed after a quality assurance test, establishing an earlier 48-yr position, recommended by wiggle-matching Bayesian statistics and dendrochronological analysis. Following this adjustment, the quantification of the 14C level variability with respect to the IntCal13 calibration curve was obtained by calculating Δ14C for all tree-ring samples. As a final conclusion, an insignificant 14C concentration offset of –0.63 ± 3.76‰ was found for the Romanian samples.

Samples presented for high-precision 14C dating must satisfy stringent requirements if the 14C determinations are to yield meaningful sharp calendric dates, such as are now possible with the bidecadal high-precision calibration curve. The total carbon content should come from a confined time range 10–20 years (10–20 tree rings in wood or charcoal) appropriate for the bidecadal calibration curve. For accurate calendric dating the relation of these rings to the outer growth rings must be known. Application of the high-precision calibration curve to some archaeologic examples is discussed. It is now up to archaeologists and geoscientists to use this refined chronometric instrument to fullest advantage.

Spermaceti is a waxy substance found in the head cavities of sperm whales (Physeter macrocephalus and P. catodon). This substance had a variety of commercial applications from the end of the 18th to the beginning of the 20th century, such as candles, soap, cosmetics and other compounds. Spermaceti was also occasionally used as wax for modeling sculptures. In order to date such artworks the marine reservoir effect (MRE) has to be considered. The chemical library of the Muséum national d’Histoire naturelle (Paris, France) contains samples of spermaceti studied by the French chemist M. E. Chevreul (1786–1889) at the beginning of the 19th century. Eight samples of substances preserved in their original containers were 14C dated. According to the whaling practices and the publications of Chevreul, we estimated that the spermaceti samples came from whales caught between 1805 and 1815. AMS 14C dating results are from 550 to 1180 ± 30 BP, R values between 393 and 1023 (± 34) 14C yr and ΔR between –168 and 504 (± 60) 14C yr. The values presented here are the first ever obtained for spermaceti. However, being based on museum specimens, further measurements on crude material would be necessary to refine these results.

Characteristics of dissolved humic and fulvic acids in river waters were studied during 2003–2005 at 4 sites located in the headwaters and in the upper and lower Tokachi River, including a lowland tributary site. Fulvic acids from the headwaters to downstream areas have similar elemental composition and 13C-NMR spectra. Humic acids have similar characteristics in the Tokachi River system. In contrast, δ13C and Δ14C values exhibit a decreasing trend from the upper to the lower and tributary sites, although the headwater site has heavier δ13C and lower Δ14C values than the upper site. Fulvic acids had similar δ13C values from the upper to lower sites, but 123′ higher in Δ14C than those of humic acids on average. The δ13C and Δ14C values exhibited differences in downward variation for humic and fulvic acids. In the Tokachi River system, these results suggest that differences in transport pathways and residence times of humic and fulvic acids reflect differences in the δ13C and Δ14C values in a single river basin.

The study the diet of Eneolithic populations is of great interest to archaeologists. However, the studies undertaken in the steppe and forest-steppe zones of Volga region in Russia have left many issues unsolved. Data collected recently through the comprehensive studies of Lebyazhinka VI settlement enable us to change this situation. Of particular importance at this settlement site is good preservation of animal bones, bone fishing tools, and ceramics of the same type with food crusts and connected to a large house pit. For the first time in this geographical area, bones of domestic animals were found in the fill of a dwelling. The aim of this paper is to present the results obtained through comprehensive studies of diet and economy in the Eneolithic based on the materials from Lebyazhinka III and Lebyazhinka VI settlement sites. The main results of the archaeozoological analysis— determinations of species, age and size of the animals—provide the necessary data for studying the diet. We conclude that there are differences between Lebyazhinka III and Lebyazhinka VI settlements. Lebyazhinka III settlement included bones of only wild species, however, Lebyazhinka VI settlement consists of wild and domestic species.

The real-time measurement of net photosynthesis and dark respiration of plants has been possible since the development of the infra-red analyzer and its application in the 1940's. This technique has allowed intensive investigations of the mechanisms and dynamics of carbon dioxide assimilation by green plants (Sestak, Catsky, and Jarvis, 1971). As a result, physiologic and ecologic aspects of net carbon dioxide exchange are the subject of much research (eg, Osmond, Bjorkman and Anderson, 1980).

Carson et al. (2016) have measured the optogalvanic response of an intracavity cell discharge containing carbon dioxide enriched in radiocarbon in a 14CO2 laser, and compared same to an unenriched sample. The measurement was carried out by modulating the laser wavelength while slowly tuning through the laser gain profile. The results of the measurements are claimed to “invalidate the optogalvanic method for radiocarbon detection.” A broadband linear absorption model is presented in support of this hypothesis. In fact, the experimental design was such as to minimize any possibility for 14C detection, and the model presented is not relevant to their experiment. Crucial control measurements were not carried out and the model used did not differentiate between broadband absorption spectroscopy and intracavity optogalvanic spectroscopy (ICOGS) with a narrow-band single-mode CO2 laser.

Late Quaternary fluvial channel deposits are notoriously difficult to date. In the midwestern United States, shells of aquatic mollusks can be found within many fluvial channel sediments and therefore can be radiocarbon (14C) dated to determine the age of the deposits. However, carbonate platform rocks are abundant in this region, potentially causing freshwater 14C reservoir effects (FRE) in mollusk shells. We 14C dated 11 aquatic gastropod and bivalve shell samples from specimens collected live from a stream in southwestern Ohio during three different years to assess the modern 14C reservoir effect. Modern samples yielded an average 14C FREmodern of 518 ± 65 14C yrs for 2020 (n=5), 640 ± 34 14C yrs for 2021 (n=2), and 707 ± 76 14C yrs for 2022 (n=4). We also 14C dated matched pairs of organic wood or charcoal and aquatic mollusk shells from late Pleistocene and Holocene deposits in the Four Mile Creek floodplain to determine the FREfossil. These samples, free of any potential influence from nuclear bomb testing, yielded an overall weighted mean FREfossil of 1029 ± 345 14C yrs. We then assess the advantages and limitations of both the FREmodern and FREfossil methods for determining freshwater reservoir effects. Finally, we apply the FREfossil correction to a series of shell ages from fluvial terrace deposits as a case study. The results indicate that although there is a 14C FRE in streams from the midwestern United States, aquatic shells can provide robust age control on fluvial channel deposits. More research is needed to understand the spatial and temporal variability of FREs, as well as any species effects, among various watersheds across the midwestern United States.

The dates presented in this paper are concerned with studies of the vegetational history of Western Scotland and are research projects in collaboration with members of staff and research students of the Sub-department of Quaternary Research, Cambridge University. The measurements of radioactivity were carried out between 1975 and 1977 at the University Radiocarbon Research Laboratory at Station Road, Cambridge, using highly purified carbon dioxide as filling gas in proportional counters. The dates are conventional radiocarbon dates calculated using the Libby half-life for the 14C isotope of 5568 years and ad 1950 as the reference year. The associated uncertainties represent one standard deviation and are calculated from a combination of the counting statistics of the samples, standards, and backgrounds together with estimates of population variation, variation of the background rate with changes of barometric pressure, and estimates of other laboratory measurement uncertainties. Thus, the stated uncertainty is considered a fairly reliable estimate of the laboratory uncertainty of the dates. The background samples are prepared from Welsh anthracite and the contemporary standard from NBS oxalic acid. A subsidiary standard is also used which is prepared from the ad 1845 to ad 1855 growth rings of an oak tree which grew near Cambridge, and the activity of this is compared frequently with the NBS standard.

The possibility to conduct new fieldwork projects in previously largely unexplored Iraqi Kurdistan during the past decade has reinvigorated research into the transformative fifth to third millennium BCE (Chalcolithic to Early Bronze Age) in southwest Asia when human societies grew from small, autonomous villages to centralized states with urban centers. Major efforts to synchronize stratigraphic sequences from various sites in order to reach a consensus on archaeological periodization and to identify the absolute chronology of societal transformations necessarily focused on available datasets from Syria, Turkey, and Iran. However, increased understanding of differences in communities’ adoption, adaptation, or rejection of new forms of technologies and social organization demands the need for constructing region-specific absolute chronological models for comparative analysis. Such work is particularly challenging in the case of Iraqi Kurdistan where sites frequently have major hiatuses in occupation. The site of Kani Shaie (Sulaymaniyah Governorate) offers the rare opportunity to investigate the Chalcolithic to Early Bronze Age with a largely uninterrupted sequence of occupation from ca. 5500 to 2500 BCE. This paper presents a series of fourteen radiocarbon dates, representing every archaeological period in this timeframe, as a first step toward the construction of a regional absolute chronology.

The AMS Golden Valley radiocarbon analysis laboratory is equipped with two accelerator mass spectrometers: AMS facility from Budker Institute of Nuclear Physics (BINP AMS) and MIni CArbon DAting System (MICADAS-28) from Ionplus AG and two graphitization systems: Automated Graphitization Equipment (AGE-3) from Ionplus AG and Absorption-catalytic setup developed in Boreskov Institute of Catalysis (ACS BIC). The laboratory provides routine 14C analyses of various samples: collagen, cellulose, humic acids, carbonates from sediments, etc. The main focus of the laboratory is to determine the age of archaeological artifacts by radiocarbon dating. This work presents a comprehensive description of the BINP AMS facility, with its operation compared with that of MICADAS in the same laboratory. In 2022, the AMS Golden Valley laboratory participated for the first time in the Glasgow International Radiocarbon Inter-comparison (GIRI). The samples were graphitized on the AGE-3 and subsequently measured in both AMS facilities. A comparison of the results of the two series of experiments, namely AGE-3 + MICADAS-28 and AGE-3 + BINP AMS, is given.