We submit that anomalies in radiocarbon data in archaeological studies should be viewed positively as a stimulus to undertake further targeted research. Additional analyses to resolve anomalies have the potential to provide important insights into heretofore unstudied or incompletely understood depositional or geochemical processes affecting 14C values, particularly in certain types of samples and samples from certain types of environments. We consider 2 major categories or sources of 14C dating anomalies that we posit are mostly responsible for the vast majority of problematic 14C results: anomalous sample contexts and anomalous sample composition. Two additional sources of 14C anomalies are much more rarely encountered. Six case studies taken from New World archaeological studies are briefly presented to provide examples of where questions concerning the validity of 14C measurements generated additional and ultimately more accurate understandings of temporal relationships. AMS-based 14C measurement technology has rendered detailed investigations of 14C anomalies routinely feasible.

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.

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.

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%.

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.

This study focuses on the chronology of King Den’s reign, the fifth ruler of the 1st Egyptian dynasty. A series of radiocarbon (14C) dates were established on archaeological material from several tombs at the Abu Rawash site, near Cairo, which comprises a complex of 12 monumental mud-brick mastabas. Modeling the 14C results enables us to estimate the date of King’s accession and to link this to the beginning of the 3rd Dynasty, i.e., to Egyptian state’s structuration. Through the application of OxCal software, sets of 14C results obtained from the same archaeological context have been summarized and compared with the precise state of our knowledge on the historical duration of this reign. These results place King Den’s accession between 3104 and 2913 BCE (2σ), with the more likely date being 3011–2921 BCE (1σ). The modeled temporal density thus obtained is based both on new contextualized 14C dates and on an updated reading of the historical information on his reign. This is a dynamic result, which can be refined as soon as we have more data to integrate into the model. Above all, this resulting model becomes a crucial chronological point to better determine the beginning of the Egyptian Old Kingdom.

Isotopic analysis of Micropogonias furnieri otoliths were used to get insight into palaeoceanographic conditions in the Guanabara Bay and Saquarema Lagoon, Rio de Janeiro state (RJ), located on the southeastern coast of Brazil, under upwelling influence of the Cabo Frio system. Archaeological otoliths come from two Holocene shellmounds (or sambaquis): Galeão and Beirada. For the first time, radiocarbon analysis using high accuracy techniques were performed at Galeão. Age range was determined to be between 5820 and 4980 cal BP, which extends the chronology of human settlement in the Guanabara Bay. Micro-samples of the otoliths were collected sequentially from the core to the edge, to provide continuous δ18O and δ13C isotopic profiles over the lifetime of the individual fish. Derived-δ18Ooto palaeotemperature estimates vary according to seasonality, resulting in a palaeoceanographic variation between 8 to 31°C for Guanabara Bay and 8 and 28°C for the Saquarema Lagoon. Our data indicate that whitemouth croakers were captured during the Middle Holocene from the Guanabara Bay and Saguarema Lagoon and resided in cooler temperatures compared to temperatures of current conditions.

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).

Human remains from the (late) Middle Paleolithic remain rare. Improving our understanding of their spatio-temporal distribution is essential for obtaining insights into human evolution and the dynamics between Neanderthals and early Anatomically Modern Humans (AMHs). We present the single-amino-acid radiocarbon dating and ancient DNA results from the only Neanderthal skeletal remains known in Slovakia (Šal’a I and Šal’a II). As they were found without archaeological context and in secondary deposition, recontextualization is important. By employing the hydroxyproline radiocarbon dating method, we were able to successfully counteract contamination issues and circumvent problems caused by highly degraded collagen. By contrast, DNA analysis did not detect any endogenous DNA at the limits of our resolution. We conclude that the radiocarbon ages of >44,800 BP (OxA-X-2731-16) and >45,100 (OxA-X-2731-15) firmly place the two individuals in the Middle Paleolithic, and before the arrival of AMHs to the region. Furthermore, indirect evidence based on morphology and possibly related faunal remains suggest ages younger than 100 ka. This time frame coincides with a period in which Neanderthal populations were highly dispersed in Europe, yet in decline.

In this paper, we present dating of archaeological samples performed since our last report (Obelić et al. 2002). Included are results of samples measured by the gas proportional counting (GPC) method until the abandonment of this technique in 2007, as well as results of several series measured by both GPC and liquid scintillation counting (LSC) methods.

The measurements reported in the following date list have been made in the Low Level Counting Laboratory of Packard Instrument Company during 1965 and are a continuation of the work reported previously (Packard I). This counting procedure for these dates has remained unchanged — a 5 ml volume of benzene counted in a Packard Tri-Carb® Liquid Scintillation Spectrometer Model 3214. The sample is converted chemically from its original form to benzene in the Packard Tri-Carb Benzene Synthesizer. This instrument was described in a general fashion in our previous publication.

Radiocarbon (14C) dating was performed for various types of precious coral colony fragments collected from the Ashizuri fishing field, around 100–200 m deep, off the southwest coast of Kochi Prefecture, Japan, to understand the historical background of one of the largest precious coral fishing fields in Japan. The 14C ages of the 55 specimens range from ~7500 years ago to the modern. Most of the measured samples were older than 1871, when fishing activities of precious corals began in Kochi Prefecture. These results suggest that most of the deaths of the precious coral colonies were due to natural causes, such as natural mortality, predation, or various forms of environmental degradation, and not strictly related to destructive fishing practices. Additionally, precious corals started inhabiting the study area at least ~7500 years ago, when the marine condition became similar to that of today after the Last Glacial Period. This study is the first to focus on the age of dead precious coral fragments and has revealed that they might be an important fossil resource that could lengthen the timespan of precious coral fishery. This additional time may enable us to establish reasonable and effective regulations for sustainable fishery.

In closing this workshop, I must thank all of the delegates for making this meeting so very enjoyable for ourselves, the organisers. So much so that we will give serious thought to inviting you back to Scotland very soon. The meeting has, in our view, been eminently successful in the scientific sense. I believe that we have made uniquely important and fundamental observations and plans for the future of 14C dating. I would like to summarise quickly my personal view of the main findings of the workshop. I would start this by recalling the eight questions posed in my opening address. The questions and my impression of the workshop's answers are as follows:

The Podemszczyzna peatland (Sandomierz Basin, SE Poland) is a place of peat exploitation for balneological purposes. The thickness of organic sediments (minerogenic peat) reaches 4.0 m, while the beginning of peat accumulation was dated using the radiocarbon method (14C) at 13,517–13,156 cal BP. During the peat exploitation numerous fragments of subfossil wood (of various species) were excavated and, based on dendrochronological analyzes and 14C dating (wiggle-matching), two short floating chronologies were elaborated: bog pine chronology (147 years long) and deciduous trees (oak, elm) chronology (139 years long). 14C dating has shown that the bog pine chronology (ca. 9980–9830 mod. cal BP) is the oldest pine chronology found in the Polish peatlands so far. It was synchronous with the Preboreal decline of fluvial activity and peat formation, whereas dying off of trees was connected with distinct rise of fluvial activity. Floating chronology of deciduous trees is much younger and encompasses time interval of ca. 680–545 cal BP. The trees’ encroachment on the peatland was related to the terrestrialization of the depositional fen, recorded in the loss on ignition curve in the form of mineral sediment delivery to the bog, as well as it is marked in the pollen record.

We present here a description of the 14C dating method used at the Institute of Geology, Estonian Academy of Science. We discuss results of geochronological studies of several stratigraphic sections, from which we estimate the age of the Late Weichselian (Late Valdaian) glacial maximum. 14C and paleobotanical data indicate that biodetrital materials comprise organic debris from various sources and suggest only a maximum age of investigated strata (16,000 BP).

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).

All background values measured in one of our 14C counters during 1977 were analyzed together with corresponding values for atmospheric pressure, outdoor temperature, and coincidence counting rate for investigation of the possibilities to separate the temperature dependency of the background from the better known atmospheric pressure dependency.

The background values were normalized to a common atmospheric pressure and plotted in a time diagram. A seasonal trend with higher background values in winter than in summer shown by this diagram was confirmed by regression analysis.

The regression line and the “Standard error of estimate” was calculated for the background values as a function of the atomspheric pressure, on the one hand and as a function of the coincidence counting rate, on the other hand. A comparison showed that the coincidence counting rate in this case was a better parameter than the atmospheric pressure for calculation of the actual background.

The approximate consistency of the temperature effects on the background was checked for the years 1976 to 1978.

Even though the reliability of equipment has improved, the quality of measurement should still be checked. This task may be performed by a microcomputer with the physicist's intervention only when an error in measurement is detected.