When ancient hearths at open archaeological sites do not yield carbonized annual plant remains or other high-quality samples, wood charcoal is commonly used for radiocarbon dating. Sagebrush (Artemisia tridentata Nutt.), a shrub frequently used for fuel across much of the western United States, seems a potentially better candidate for 14C dating than tree wood since the possibility for significant age discrepancy might be less. A comparison of multiple assays from single features reveals that sagebrush can overestimate age more than even tree wood charcoal. A plausible cause of this appears to be persistence of the shrub on the ground surface for an extended interval after death, such that use as fuel almost invariably occurs hundreds of years after fixation of carbon. The potential for age discrepancy may decrease as population density increases because the demand for fuel wood would have resulted in a more rapid turnover of the fuel biomass. This is not true for Archaic period foragers of western North America when population levels were likely quite low and residential mobility quite high.

We assess the state of and potential for expansion of dendroarchaeological research in Egypt. We also report previously unpublished findings, which we hope will assist with the new effort in constructing tree-ring chronologies in Egypt. In doing so, we explain briefly some of the problems and potential of the future enterprise.

The Radiocarbon Laboratory under the Chair of Nuclear physics of Tbilisi State University is engaged in studies of radiocarbon variation in the atmosphere and mineral waters and determination of the absolute age of archaeologic, geologic, botanical, and other samples. This list reports dates of archaeologic and geologic specimens only. Gas counting and liquid scintillation methods are used for dating.

We present new marine reservoir ΔR correction terms for the central and northern Kuril Islands. We estimate ΔR from a series of archaeological charcoal-shell pairs from two archaeological sites using standard calibration procedures and Monte Carlo simulation. The combined ΔR estimate for all paired samples for the Kuril samples is 508±127 yr. In the context of available North Pacific Rim ΔR estimates, the new Kuril data support the interpretation of a well-mixed, 14C-depleted North Pacific Subarctic Gyre. For the broader subarctic North Pacific region, a ΔR estimate in the range of 440±127 yr is a reasonable correction for any coastal marine shell date, and may be applied to fish and marine mammal dates for taxa known to reside within these waters throughout their life-histories. This generalization fails as one moves south from Hokkaido along the East Asian coast. There, well-equilibrated subtropical water minimize the ΔR offset.

Hala Sultan Tekke is a large Bronze Age city located on the southeastern littoral of Cyprus. The city flourished from approximately 1650 BC to 1150 BC according to the archaeological evidence. Since 2010, Swedish excavations have exposed four new city quarters (CQ1–4) with three occupational phases, the 14C dating of which is of highest importance also for other contemporaneous cultures. The finds demonstrate vast intercultural connections in the Mediterranean and even with southern Scandinavia. In 2014, roughly 500 m to the east of CQ1, one of the richest cemeteries on the island was discovered. According to the archaeological evidence, the finds from the city date mainly to the 13th and 12th centuries BC. However, many of the wealthy tombs and the offering pits from the cemetery are considerably older with the oldest finds dating to the 16th century BC. This raises the question where the city quarters belonging to the oldest finds from the cemetery are situated. The radiocarbon (14C) dates from Hala Sultan Tekke have much influence on the dating of related sites because of numerous imports from a vast area. We present here new 14C data obtained in the course of the current excavations, which add to sets of already existing data.

In order to contribute to the discussion of Holocene climate changes, four sediment cores were collected from the northern Brazilian Amazonia lowland. These cores were studied through pollen analysis and sedimentary features, and the results were discussed within a chronological framework provided by radiocarbon dating. The cores were sampled from fluvial terraces representative of channel, floodplain/lake and crevasse splay deposits formed since the mid-Holocene. The pollen samples derive from floodplain/lake deposits and the pollen grains are mainly composed by families Moraceae, Euphorbiaceae, Caesalpiniaceae, Fabaceae, Rubiaceae, Melastomataceae, Combretaceae, Sapindaceae, Poaceae, Cyperaceae, Aizoaceae, Apiaceae and genus Sebastiana. The pollen data suggest no significant vegetation changes in the study area for the past 4808–4886 cal yr BP. This led to proposing stable climatic conditions since at least the middle Holocene. Such a finding is contrary to the occurrence of a dry period during the middle Holocene. The stabilization of the relative sea level about 6000 cal yr BP along the northern Brazilian littoral may have influenced the water table, and favored the establishment and maintenance of Amazonian lowland forest during the mid- and late Holocene. In addition, this process may have attenuated the impact of that dry period in areas under most fluvial influence.

The list of dates grouped below is a continuation of work reported in our earlier lists. In one case (Core A 254-BR-C), an extensive sequence of dates is reported which, for completeness, includes some data presented in an earlier report (Miami II, 1963).

We continue to use a 1.0-L CO2 proportional counter operating a 3 atm pressure (see Stockholm V for details). Except for the early incorporation of a counter for tritium analyses within our present shielding house and switching over to transistorized electronics, we do not anticipate changes in our set-up.

Wherever possible we have entered the δC13 corrected date as well as the δC13 value determined from that sample. An apparent 400-yr sea-surface carbonate age is subtracted from the calculated age of marine carbonate materials, but not for organic material (Miami I and Miami II).

Systematic treatment of the data recorded by our guard counters and corrections introduced for meteorological factors has allowed observations on solar events clearly manifested in the readings. Examples are the solar flares of March 1989 and especially of June 1991, which caused a ca. 10% decrease in the cosmic radiation flux reaching the counters. A sinusoidal variation in the cosmic-ray flux with a period of one year is also clearly manifested in the data. The observation that the background in the 14C measurements depends on the intensity of the cosmic radiation has led to the use of monthly correlations for the determination of the best background value to be used in the age calculations. This reduces the error significantly. However, various factors such as random statistical fluctuations of the background measurements may affect the slope of the correlations and consequently the calculated age of the samples. Long-term observations of the relation between background values and coincidence counts have led to constraints in the slope of the correlation. A simple extension of the fitting procedure is explored, which maintains the physically meaningful range of the slopes, but is flexible to adjust for the seasonally varying contributions to the variations of the cosmic-ray flux.

This list includes about half of the samples measured during the last year. Many studies need further investigation and the results will be published later when additional information will make better interpretations possible.

The equipment and the technique is essentially the same as described earlier (Bern IV).

Reliable results on CO2 samples extracted out of ice are obtained with the small counter mentioned in Bern IV.

Our laboratory is financed by the Schweizerischer Nationalfonds. The authors wish to thank H. Loosli and P. Horisberger for their assistance in the measurements of part of the samples. They also thank M. Welten and H.-G. Bandi for their help in selecting and discussing the samples.

Lime (grouting) from old structures near city of Khar'khov [50° 00′ N Lat, 36° 10′ E Long]. Subm. [n.d.] by L. P. Papkova.

Kauri wood, a sub-fossil wood from New Zealand (which had previously been used in an IAEA exercise, IAEA-C4, in 1990), was considered to be an important sample to include in FIRI because it provided a link to previous exercises, was available in sufficient quantity, and was a “close to background” organic sample. IAEA-C4 had previously been criticized since it was believed that in its milling, some contamination had been introduced, so that a replacement sample would prove useful. The Kauri wood has a very low 14C activity and, as such, is very sensitive to even small amounts of contaminant carbon. Such low-activity samples give a true test for the laboratory procedures since pretreatment and laboratory background definition become critical.

The Ongamira Valley (Córdoba, Argentina) shows a persistent occupational history of its territory. Even one of the first Argentinian radiocarbon (14C) dates was calculated in this valley; for 70 years, the chronology was based on relative dates (stratigraphy and its cultural content). For this reason, since 2010 a 14C dating program has been developed focusing on the chronology of eight of the 60 sites identified so far for the valley. This work reports the outcomes of this program with 27 new dates. These data have been related to characteristics of the material culture, use of space and mobility of hunter-gatherer societies. The results have allowed us to bring new insights into a continuous occupation of the valley since the Middle Holocene according to the human peopling models proposed. It has also been possible to provide greater chronological precision to various activities related to feeding practices, use of space associated with rock-shelters, palaeoenvironmental changes and incorporation of new technologies into daily practices.

Northeastern North America has produced an incredible number of late Pleistocene faunal remains; however, many of these were discovered and excavated prior to the development of radiocarbon dating. Moreover, many of the 14C dates that do exist for such specimens were assayed prior to the development of purified collagen extraction methods, were performed on botanical remains of unspecified association with the faunal remains, or were accepted without concerns of young-carbon contamination from museum preservatives. Here, we present a set of high-precision accelerator mass spectrometry (AMS) dates obtained on Pleistocene faunal specimens from Connecticut, New Jersey, and Pennsylvania. Our data contain both newly discovered specimens and specimens that have resided in museum collections for over a century.

Vitória Bay is located in the south-central part of the State of Espírito Santo (SES). Multiproxy analyses were performed on samples from a 490-cm-long sediment core collected at the coordinates 40°18′23′′W and 20°14′48′′S. The objective of this study was to identify and integrate the multiproxy data to determine the environmental dynamics during the Holocene. The material was subsampled every 10 m and submitted to standard methodological processing. The sediment core was dated to two depths: the oldest age was between 9396 and 9520 cal yr BP at a 480-cm depth, and the youngest age was from 7423 to 7511 cal yr BP at a 304-cm depth. The integrated analysis revealed evidence of three major environmental changes in Vitória Bay. The first phase had a fluvial influence (depth of 490–480 cm; 9396–9520 cal yr BP). This was followed by a transitional period (depth of 480–290 cm; 7423–7511 cal yr BP) with a salt influence due to the Last Marine Transgression (LMT). Later, the environmental stability was similar to that of today (290 cm to the core top). This was a reflection of the Last Marine Regression (LMR) in the Holocene.

Nitrogenous compounds of soil organic matter constitute a major N reservoir on Earth. Both the world food protein supply produced by agriculture and the global contamination by reactive nitrogen species rely on the dynamics of these compounds. To investigate their dynamics, we used both natural 13C labeling and accelerator mass spectrometry (AMS) 14C dating of the α-carboxyl amino carbon, which is specific of the amino acid fraction that was extracted from bulk soil organic matter by ninhydrin hydrolysis. We applied this isotopic approach to investigate the age of carboxyl carbon in a maize-cultivated Cambisol chronosequence. Based on a few measurements, we demonstrate the feasibility of this new compound-specific method of investigation of soil carbon dynamics. We show that soil organic matter amino acids can be split into two very distinct dynamic compartments: the majority having a mean age of a few years and a minority having a mean carbon age of several millennia. The latter fraction can be either strongly stabilized in soils, or can arise from microbial utilization of old carbon resources, as predicted by the priming effect theory.

The peat bog at Homoródszentpál Kerek-tó (Round Lake), situated in Homoród Hills of the Eastern Carpathians in Romania, provides a continuous record of paleoclimatic and paleoenvironmental changes from the Early Holocene. In this study, we present a 7500-year-long high-resolution record of past climatic changes and signs of human impact recorded in a peat bog via integrating sedimentological, paleoecological and geochemical proxies. The basin of Round Lake formed around the Pleistocene–Holocene border when the permafrost thawed. Ponded water accumulated in the catchment basin from the beginning of the Holocene but ca. 7500 cal BP years ago lacustrine sedimentation was exchanged for peat accumulation. The 570-cm-long core was subsampled at 2–4 cm intervals and subjected to grain-size, loss-on-ignition (LOI), pollen, and radiocarbon (14C) analyses. Our findings were correlated with and interpreted in the light of paleobotanical records deriving from archaeological sites and the newest bioclimatological models of the nearby areas. Sedimentological analysis document erosion and accumulation events which were influenced by more complex processes like climate change. Based on environmental historical and climatic data we aimed to reconstruct the environmental changes of forested areas in the Homoródi Hills.

The Aqueduct is one of the city landmarks of Skopje, Republic of North Macedonia. It was part of a water-supply system, with a total original length of about 10 km, while its surface remains are about 385 m long. The age of the Aqueduct is not known—several hypotheses place it to periods between the 6th and 16th centuries. Six mortar samples from different positions of the eastern façade were taken for radiocarbon (14C) dating. In order to extract only the carbon associated to the time of building, three strategies for sample preparation were used: (1) mechanical separation of lime lumps formed during mortar hardening (2) selection on the basis of particle size and the ability to suspend in water induced by ultrasonic shock, and (3) collection of two gas CO2 fractions produced from the same bulk in reaction with acid. Characterization of fractions was performed by isotopic carbon composition and FTIR-ATR analyses. The most plausible results were obtained from lime lump fractions that were dated in the timeframe of 15th to 17th century.

The use of computer data bases for storage and retrieval of 14C data is a logical application for the rapidly expanding numbers of 14C determinations. Harwell has established a data base for all samples originating from sites in the United Kingdom and Eire. The core of the data is the Council for British Archaeology's published Index of Radiocarbon Dates which we are expanding to include all Harwell UK dates released for publication by the submitters plus dates from other laboratories both within and outside the UK. As a demonstration of the feasibility of direct database-to-database communication, cooperation has been sought from Groningen and Oxford to transfer computer files containing 14C results for UK sites. Neither of these laboratories use the same system as Harwell for their in-house data base and this exercise highlights the importance of a transfer language for both the national and international schemes as it is no longer practical to carry out such procedures through keyboard typing.

This paper proposes the use of the statistical bootstrap technique as an aid in combining radiocarbon date estimates The rationale for the use of the bootstrap is the theoretical result that, even if individual date estimates are normally distributed, their combination by the usual formula results in a random quantity that is not normal but rather a mixture of distributions. The bootstrap is a non-parametric, computer-intensive technique. This technique can better estimate the actual distribution of the combined age, leading to more precise confidence intervals. While the bootstrap cannot solve the multiple-intercepts problem in calibration, it can nonetheless lead to better estimates. The benefits of using the bootstrap are especially noticeable when sample sizes are small (as is the case in other applications of this technique).

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.