This paper summarizes radiocarbon measurements of mainly botanical samples from the Iceman (“Ötzi”) and from his discovery site, an Alpine glacier at the Austrian-Italian border. The results were obtained by accelerator mass spectrometry (AMS) at 3 different laboratories (Vienna, Austria; Uppsala, Sweden; Gif-sur-Yvette, France) between 1992 and 1997. All the dates, except 2, are consistent with the time period 3360–3100 BC, as previously determined from bone and tissue samples from the Iceman himself. The 2 exceptional dates from wooden artifacts suggest that the site of the Iceman was used as a mountain pass for millennia prior to and after the lifetime of “Ötzi”.

For a 2nd sample complex, we studied logs from the beginning of salt mining in the world's oldest salt mines at Hallstatt in Upper Austria. 14C AMS measurements were performed in Vienna on spruce samples found in the prehistoric mines and from a log-house on the surface. Data evaluation included “wiggle matching” of different sets of tree rings. The results suggest that salt mining in the Hallstatt region took place in the 14th–13th century BC, well before the so-called Hallstatt period.

We discuss in some detail the chemical pretreatment of the samples and the data evaluation. We also present a comprehensive survey of 14C dates available in the literature concerning both botanical remains from the vicinity of the Iceman and from the earliest salt mining in Hallstatt.

Radiocarbon dating has had profound implications for archaeological understanding. These have been identified as various “revolutions,” with the latest—Bayesian chronological statistical analyses of large datasets—hailed as a “revolution in understanding.” This paper argues that the full implications of radiocarbon (14C) data and interpretation on archaeological theory have yet to be recognized, and it suggests that responses in Britain to earlier revolutions in archaeological understanding offer salutary lessons for contemporary archaeological practice. This paper draws on the work of David Clarke and Colin Renfrew to emphasize the importance of critical considerations of the relationships between archaeological theory and scientific method, and to emphasize that seemingly neutral aspects of archaeological thought are highly laden interpretatively, and have significant implications for the kinds of archaeology that we write.

In July 1986, an AMS radiocarbon target preparation laboratory was established at the Woods Hole Oceanographic Institution to produce graphite to be analyzed at the NSF-Accelerator Facility for Radioisotope Analysis at the University of Arizona (Tucson). By June 1991, 923 graphite targets had been prepared and 847 analyzed. Our lab procedures during this time included the careful documentation of weights of all starting samples, catalysts and final graphite yields, as well as the volume of CO2 gas evolved during CaCO3 hydrolysis or closed-tube organic carbon combustions. From these data, we evaluate the methods used in general and in our lab.

We list measurements carried out between June and November 1968. Archaeologic samples are from Italian and Swat (W Pakistan) territories; all geologic samples are from Italian territory.

Chemical preparation of samples, measurement technique, and the modern standard are unchanged (Bella and Cortesi, 1960; Alessio, Bella, and Cortesi, 1964; Alessio et al., 1968).

For each sample of CO2 the counting rate was corrected according to mass-spectrometrically measured C13/C12 ratio. Isotopic analyses were carried out with a 6 in., 60°-sector, double-collecting mass spectrometer, designed and built by G. Boato at Ist. di Fisica, Univ. of Genoa (Boato et al., 1960) and now in use at Ist. di Geochim., Univ. of Rome. C13/C12 ratio is reported as δ-value, the deviation in parts per mil of the C13/C12 ratio of sample from the PDB standard:

Accelerator mass spectrometry (AMS) radiocarbon measurements were made on 120 samples collected between Antarctica and South Africa along 30°E during the WOCE-France CIVA1 campaign in February 1993. Our principal objective was to complement the Southern Ocean's sparse existing data set in order to improve the 14C benchmark used for validating ocean carbon-cycle models, which disagree considerably in this region. Measured 14C is consistent with the θ-S characteristics of CIVA1. Antarctic Intermediate Water (AAIW) forming north of the Polar Front (PF) is rich in 14C, whereas surface waters south of the PF are depleted in 14C. A distinct old 14C signal was found for the contribution of the Pacific Deep Water (PDW) to the return flow of Circumpolar Deep Waters (CDW). Comparison to previous measurements shows a 14C decrease in surface waters, consistent with northward displacement of surface waters, replacement by old deep waters upwelled at the Antarctic Divergence, and atmospheric decline in 14C. Conversely, an increase was found in deeper layers, in the AAIW. Large uncertainties, associated with previous methods for separating natural and bomb 14C when in the Southern Ocean south of 45°S, motivated us to develop a new approach that relies on a simple mixing model and on chlorofluorocarbon (CFC) measurements also taken during CIVA1. This approach leads to inventories for CIVA1 that are equal to or higher than those calculated with previous methods. Differences between old and new methods are especially high south of approximately 55°S, where bomb 14C inventories are relatively modest.

This paper presents the results of the first broad-scale study of modern freshwater reservoir effects (FREs) in various regions of the Eurasian Steppe, associated with archaeological sites. The aim of this work was not only to demonstrate the widespread variability of modern FREs in the region, but also to draw the attention of specialists working in the area to the necessity of taking into account this important and still not fully understood factor involving radiocarbon dating of human and some faunal remains from archaeological sites. To identify modern FREs, modern fish of different species from 10 regions of Siberia and Kazakhstan have been subjected to accelerator mass spectrometry radiocarbon (AMS 14C) dating and stable carbon and nitrogen isotope analysis, and the results are compared with the existing data from previous research. Freshwater reservoir offsets have been detected in all analyzed regions, with the exception of Kharga Lake (Buryatia, Russia) and Kyzylkoi River (central Kazakhstan), varying not only between, but also within regions depending on fish species. The most significant offset in this study has been recorded for the Chuya River basin (Altai Mountains, 1097±40 14C yr), though not as high as observed in previous research for the Caspian lowlands (1477±52 and 1037±52 14C yr) and Upper Lena River basin (Lake Baikal area, 1981±30 14C yr). Both δ13C and δ15N values have been measured with the majority of samples reflecting C3 ecology of local reservoirs and δ15N depending on the diet of particular species, with predatory species such as pike, perch, and burbot demonstrating the highest δ15N. No general relationship has been observed between freshwater reservoir offsets and either δ13C or δ15N values of the samples.

Radiocarbon accelerator mass spectrometry (AMS) measurements are always carried out relative to internationally accepted standards with known 14C activities. The determination of accurate 14C concentrations relies on the fact that standards and unknown samples must be measured under the same conditions. When this is not the case, data reduction is either performed by splitting the collected data set into subsets with consistent measurement conditions or by applying correction factors.

This paper introduces a mathematical framework that exploits the intrinsic variability of an AMS system by combining arbitrary measurement parameters into a normalization function. This novel approach allows the en-masse reduction of large data sets by providing individual normalization factors for each data point. Both general features and practicalities necessary for its efficient application are discussed.

Maps of accumulation rates of freshwater diatoms and opal phytoliths in the surface sediments of the Zaire fan show that both types of microfossils were supplied to the ocean floor by the Zaire River, and that opal phytoliths also have a southern source, probably the region of the Namibian desert. The PhFD ratio, of opal phytoliths to freshwater diatoms, can be regarded as an aridity index for equatorial Africa, and probably for large parts of the central and southern Atlantic. In two cores, the record of the PhFD ratio indicates humidity ca 225–190 ka BP, aridity 190–135 ka BP with maxima ca 170 and 140 ka BP and a humid excursion 150 ka BP, an increase in humidity 115 ka BP, a less humid period 90–30 ka BP, more humidity ca 30–17 ka BP with possibly more arid intervals ca 22.5 and 20 ka bp. In general, glacial (sub) stages were more arid and interglacial (sub) stages more humid. For the last 20 ka, the PhFD ratio corresponds closely with the known climatic events in tropical Africa.

Radiocarbon (14C) dating has previously been applied to modern paintings on canvas from the 20th century to identify potential modern forgeries, and dates indicate a time lag of several years between the harvesting of plant fibers for making canvas, and completion of a painting. This study investigated both the length of this time lag and the potential of 14C dating to inform about an individual artist’s mode of working (for example long-term storage or reuse of canvases, or extended reworking on a single canvas) and/or to establish a chronology for a corpus of work. Two pre-bomb and 16 post-bomb artworks by 17 mid-20th-century Scandinavian artists were 14C dated. The majority of post-bomb samples indicated a time lag of 2–5 years between the harvesting of the plants and completion of a painting, but some samples recorded lags of up to 10 years, and others produced much earlier results, potentially indicating the use of much older canvases or challenges removing contamination prior to dating. The importance of thorough pre-screening of canvas samples for both synthetic fibers and contaminants prior to dating, and selection of the most suitable calibration curve, are highlighted.

This report covers the investigations of the Laboratory of Archeological Technology of the Institute of Archeology of the Academy of Sciences of the U.S.S.R. under the technical direction of Corresponding Academician I. Ye. Starik. This work was begun in 1956, but the bulk of the dates were obtained during 1959–61 by the ethyl-benzol technique. For a control, ethyl-benzol was synthesized from the annual rings of the heartwood of an 80-yr-old larch. Depending on the size of the sample submitted for analysis, from 15–70 ml of ethyl-benzol was used.

We report here first results on the bulk soil organic carbon (SOC), apparent radiocarbon ages and δ13C characteristics of the tropical and subtropical forest soil in Dinghushan Biosphere Reserve (DHSBR). The forest oxisol in Dinghushan has developed during the Holocene. The δ13C variation curves in all three profiles may be divided into two sections. The upper section from 0 to 40 cm has δ13C values varying from −27.4 to −24.1‰, −27.5 to −22.2‰, and −24.4 to −20.1‰. in the Wukesong, Qingyunsi and Kengkou profiles, respectively. The lower section, including the 40–160 cm horizons, has a uniform δ13C. The mean δ13C values of the soil organic carbon could be used not only to discriminate between C3 and C4 plants, but also to distinguish between coniferous and broad-leaf plants.

The dates and activity measurements given below have been obtained during 1964 and 1965, and have been made with CO2 at 3 atm pressure in a proportional gas-counter as described in previous contributions from this laboratory. We have continued to concentrate chiefly upon research projects pursued in the University Sub-department of Quaternary Research.

We report the chronological construction for the top portion of a speleothem, PC1, from southern Cambodia with the aim of reconstructing a continuous high-resolution climate record covering the fluorescence and decline of the medieval Khmer kingdom and its capital at Angkor (~9th–15th centuries AD). Earlier attempts to date PC1 by the standard U-Th method proved unsuccessful. We have therefore dated this speleothem using radiocarbon. Fifty carbonate samples along the growth axis of PC1 were collected for accelerator mass spectrometry (AMS) analysis. Chronological reconstruction for PC1 was achieved using two different approaches described by Hua et al. (2012a) and Lechleitner et al. (2016a). Excellent concordance between the two age-depth models indicates that the top ~47 mm of PC1 grew during the last millennium with a growth hiatus during ~1250–1650 AD, resulting from a large change in measured 14C values at 34.4–35.2 mm depth. The timing of the growth hiatus covers the period of decades-long droughts during the 14th–16th centuries AD indicated in regional climate records.

In this contribution, we establish a radiocarbon-based chronology of early ceramic sequences in eastern Fennoscandia utilizing a Bayesian approach. The data consist of 56 individual 14C dates from charred or fermented food remains (charred crust, food residue) and birch bark tar used to seal cracks in vessels. We present the results of the models, discuss the chronological boundaries obtained, and compare the outcome with contemporary archaeological knowledge of the Subneolithic in eastern Fennoscandia. We also look at the role of charred crust δ13C values as indicators of reservoir effect present in the dates, perform some preliminary correction procedures for the dates, and discuss their effect on the chronologies.

Following recommendations of the Glasgow International Workshop on Intercomparison of Radiocarbon Laboratories (Scott, Long & Kra 1990), a further international intercomparison is planned. This new intercomparison is complementary to the existing IAEA intercalibration, and will make use of natural samples whose ages will be unknown to the participants. The study has been funded by the UK Research Councils (SERC and NERC), and samples will be free to all participants. We anticipate that this intercomparison will be ongoing, with distribution of samples in 1992, and presentation of the results at a later meeting. We present here details of the samples available and the time scale of the study. Briefly, we envisage that the new study will be more focused than the ICS (Scott et al. 1986), and will include natural samples in both pretreated and unpretreated forms.

Recently, in an intercomparison of the Hohenheim German oak chronology (Becker 1993) and the Göttingen chronology (Leuschner and Delorme 1988), an error was discovered in the former (Leuschner, in preparation). Due to an error in adding sections at 5241 bc, 41 yr are missing in the published Hohenheim chronology. After correction of the error, the two chronologies synchronize over their entire common length, back to 7200 bc.

Dense speleothem samples are considered as closed systems and are, therefore, possibilities for any dating method. Four dating methods (14C, U/Th, paleomagnetism, and electron spin resonance = ESR) were used for samples up to 1,000,000 yr old and taken along a vertical flowstone profile in the Heggen cave in West Germany. Also δ18O and δ13C analyses were carried out.

The reliability of the results of each method is dependent on the diagenetic processes that took place during the complex growth history of the flowstone. Speleothem growth was interrupted during glacial periods. During interglacial periods, at least the stalagmite growth rate was greater by one order of magnitude than during interstadial periods. During the periods of low interstadial growth rate various processes might have changed the 14C, 18O, and 13C concentrations, leaching might have removed uranium, recrystallization might have moved thorium several centimeters, and increased content of radon in the cave might have exaggerated the accumulated dose (AD) at the speleothem surface. As a result, 14C ages may be too small and U/Th as well as ESR data may be too large.

Since the beginning of the Holocene, hunter-gatherers have occupied the central-south Brazilian coast, as it was a very productive estuarine environment. Living as fishers and mollusk gatherers, they built prehistoric shellmounds, known as sambaqui, up to 30 m high, which can still be found today from the Espírito Santo (21°S) to Rio Grande do Sul (32°S) states, constituting an important testimony of paleodiversity and Brazilian prehistory. The chronology of the Sambaqui da Tarioba, situated in Rio das Ostras, Rio de Janeiro, is discussed herein. Selected well-preserved shells of Iphigenia brasiliana and charcoal from fireplaces in sequential layers were used for radiocarbon dating analysis. Based on a statistical model developed using OxCal software, the results indicate that the settlement occupation begun most probably around 3800 cal BP and lasted for up to 5 centuries.

We present a time-saving modification to the ultraviolet (UV) oxidation method for analyzing dissolved organic carbon (DOC) concentration, Δ14C, and δ13C measurements in seawater and standard materials. A low background (∼0.2 ± 0.2 μM) was reported for pre-irradiated Milli-Q (MQ) water that was used to dilute samples for DOC 14C analysis (Beaupré et al. 2007). We use MQ water without pre-irradiation (background ∼0.9 ± 0.2 μM) to dilute the sample. This method is suitable for small-volume, high-concentration samples (mass of sample DOC overwhelms mass of MQ water DOC). An acceptable precision of Δ14C measurements (5–9‰) is maintained. This revised method reduces the preparation time for diluted DOC Δ14C samples from 2 days to 1 day.

The production of radioisotopes at the Earth's surface by cosmic-ray effects has been discussed for many years. Only in the past few years, with the higher sensitivity provided by accelerator mass spectrometry (AMS) in detecting 10Be, 26A1 and 36Cl, have the radioisotopes produced in this way been measured. We report here our measurements of cosmogenic 14C in terrestrial rocks at high altitude, and comparisons to other exposure-dating methods.