A study of water and carbon isotopes was conducted in a bare plot in the unsaturated zone of the Yatir Forest in the northern Negev of Israel. Sediment cores were collected in three different seasons. Measurements include profiles of mineralogy, moisture and its δ18O and tritium content, dissolved inorganic carbon (DIC) and its δ13C (‰) and Δ14C (‰) content, and δ13C (‰) and Δ14C (‰) in the solid sediment. The profiles of moisture and δ18O in the cores show clearly the effect of evaporation. The tritium profile indicates infiltration of water (0.11 m yr−1). The source of carbon in the DIC is CO2 released by biotic activity through roots of trees and of seasonal plants, which show seasonal variations, and by decay of organic debris. The δ13C (‰) profiles show clearly the chemical transition from dissolved CO2 (δ13C = −22‰) to bicarbonate (δ13C = −14‰). At greater depth (–11.3‰), the δ13C becomes similar to the δ13C in the aquifer below (–12.5‰). The effect of secondary processes is evident in the profile of Δ14C in the DIC. It shows a clear decrease with depth due to exchange with the sediment at a rate of 10‰ yr−1. Precipitation of carbon from the DIC on the sediment is 1.1 mg C Lsed−1 yr−1, negligible compared to the 28 g C in 1 Lsed. In the solid sediment, there is a gradient in Δ14Ccarb at the top meter. The net precipitation of 14C from the DIC on the sediment (0.25 to 1.1‰ yr−1), corrected for decay, cannot be observed in the deeper sediment. The presence of 14C in the top 1 m of the sediment is explained by two possible processes: accumulation of 14C-tagged dust (∼0.05 mm yr−1) and/or long-term cumulative precipitation from the DIC.

This article presents the results of radiocarbon dating and a chronology of the Preobrazhenka 6 site of the Odino culture (Baraba forest steppe, western Siberia). Currently available 14C data for the necropolis do not allow accurate determination of the presence or absence of reservoir effects, and as such, further research is needed. Accelerator mass spectrometry (AMS) 14C dating of paired samples of terrestrial faunal and fish remains from a Neolithic pit suggest the absence of a reservoir effect in fish bone collagen. Middle Bronze Age burials have therefore been estimated to date to the 23rd–20th centuries cal BC. Pits with fish remains are dated earlier than burials, to the 63rd–61st centuries cal BC. Stable isotope measurements of human bone collagen (high δ15N and low δ13C values) indicate diets based on C3 plants and fish. Apparently, the role of animal protein in the diet was not significant. Dental paleopathology analysis has confirmed the important role of wild plants in human diet. Neolithic fish bones are elevated in δ13C [–13.5‰, average mean (n = 4)]. They are significantly different from the associated values of fish from the Late Bronze Age settlement of Chicha 1 [–22.5‰, average mean (n = 10)], which is also located in the Baraba forest steppe. The difference in δ13C values in fish bones may be determined by the origin of the samples, being derived either from lakes or rivers.

Radiocarbon dates obtained for the coastal hilltop settlement of Aghios Antonios Potos in south Thasos are statistically treated to define the absolute chronology for the start and the end of the various habitation and cultural phases at the site. The location was first occupied during the Final Neolithic (FN) between 3800 and 3600 BC, extending this much contested phase to the lowest up to now record for Thasos and the northern Greece. The site is continuously inhabited from Early Bronze Age I until the early Late Bronze Age (LBA; 1363 BC) when it was abandoned. Comparison with other sites in Thasos and particularly with the inland site of Kastri Theologos showed that the first occupation at Aghios Antonios came soon after the abandonment of Kastri in the beginning of the 4th millennium. In fact, after the decline and abandonment of Aghios Antonios in the LBA, the site of Kastri was reinhabited, leading to the hypothesis that part of the coastal population moved inland. The presumed chronological sequence of alternate habitation between the two settlements may evoke explanations for sociocultural and/or environmental dynamics behind population movements in prehistoric Thasos. A major conclusion of the project is that the 4th millennium occupation gap attested in many sites of Greece, especially in the north, is probably bridged in south Thasos, when the data from all sites are taken together. The mobility of people in Final Neolithic south Thasos may explain the general phenomenon of limited occupational sequences in the FN of north Greece.

This article surveys ongoing research of the Legibility Enhancement of Ostraca (LEO) team of Tel Aviv University in the field of computerized paleography of Hebrew Iron Age ink-written ostraca. We perform paleographic tasks using tools from the fields of image processing and machine learning. Several new techniques serving this aim, as well as an adaptation of existing ones, are described herein. This includes testing a range of signal-acquisition methodologies, out of which multispectral imaging and Raman spectroscopy have matured into imaging systems. In addition, we deal with semior fully automated facsimile construction and refinement, facsimile, and character evaluation, as well as the reconstruction of broken character strokes. We conclude with future research directions, addressing some of the long-standing epigraphic questions, such as the number of scribes in specific corpora or detection of chronological concurrences and inconsistencies.

Black carbon (BC) from incomplete combustion of organic materials is abundant in many soils. Its age is often higher than that of thermally unaltered soil organic carbon (SOC) owing to the presence of BC from fossil sources or to a high recalcitrance against microbial decomposition compared to that of plant residues. For a meaningful application of radiocarbon as an indicator for soil carbon age and turnover, the relative contribution of BC needs to be quantified, but BC is difficult to separate physically from soil. However, BC is thermally more stable than SOC, and hence thermal stability may provide a quantitative BC indicator. Here, we analyzed 30 light particulate organic carbon (POC) soil fractions for their thermal stability and for their 14C signature. POC is particularly sensitive to “contamination” with BC, because it is obtained by combined size and density fractionation. A steady-state “bomb” 14C model was used to derive mean POC ages. Soils from four sample sets, each consisting of six to eight individual POC samples and representing different field sites and POC types, were analyzed. Samples from one of the sets were virtually BC free, and their mean POC ages ranged from 60 to 100 yr. The 14C signature of samples from the other three sets indicated the presence of very old carbon, with mean POC ages of several hundred and up to 3500 yr. Two indicators for thermal stability—(1) the amount of heat released at temperatures >450°C and (2) the amount of heat released at 500°C (the latter representing the peak temperature of heat released from charcoal isolated from soil)—correlated both significantly and nonlinearly with POC age, indicating that samples with high BC content were older than those with low BC content. It can be concluded that at an individual site with increasing abundance of BC, both the age and the thermal stability of POC increase. However, thermal stability proved to be a reliable predictor for BC in only one sample set, whereas thermal signals of the other two BC-containing sample sets were not significantly different from those of BC-free samples. Thermal stability thus gives no unequivocal indication for the presence of BC in POC across different sites.

This article presents a case study of Lower Lough Erne, a humic, alkaline lake in northwest Ireland, and uses the radiocarbon method to determine the source and age of carbon to establish whether terrestrial carbon is utilized by heterotrophic organisms or buried in sediment. Stepped combustion was used to estimate the degree of the burial of terrestrial carbon in surface sediment. Δ14C, δ13C, and δ15N values were measured for phytoplankton, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). Δ14C values were used to indicate the presence of different sources of carbon, including bedrock-derived inorganic carbon, “modern,” “recent,” “subsurface,” and “subfossil” terrestrial carbon in the lake. The use of 14C in conjunction with novel methods (e.g. stepped combustion) allows the determination of the pathway of terrestrial carbon in the system, which has implications for regional and global carbon cycling.

In response to the increasing demand for 14C analysis of samples containing less than 25 μg C, ultra-small graphitization reactors with an internal volume of ∼0.8 mL were developed at NOSAMS. For samples containing 6 to 25 μg C, these reactors convert CO2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. Graphite targets produced with the ultra-small reactors are measured by using the Cs sputter source on the CFAMS instrument at NOSAMS where beam current was proportional to sample mass. We investigated the contribution of blank carbon from the ultra-small reactors and estimate it to be 0.3 ± 0.1 μg C with an Fm value of 0.43 ± 0.3. We also describe equations for blank correction and propagation of error associated with this correction. With a few exceptions for samples in the range of 6 to 7 μg C, we show that corrected Fm values agree with expected Fm values within uncertainty for samples containing 6–100 μg C.

The Late Bronze Age to Iron Age transition in the coastal southern Levant involves a major cultural change, which is characterized, among other things, by the appearance of Philistine pottery locally produced in styles derived from outside the Levant. This transition in the coastal southern Levant is conventionally dated to the 12th century BC, based on historical and archaeological artifacts associated with the Philistine pottery. Radiocarbon dating can provide a more precise independent absolute chronology for this transition, but dating for the period under discussion is complicated by the wiggles and relatively flat slope in the calibration curve, which significantly reduce precision. An additional complication is that the stratigraphic record below and above the transition at this site, as well as at most other sites in the region, is far from complete. We thus used a variety of microarchaeological techniques to improve our understanding of the stratigraphy, and to ensure that the locations with datable short-lived materials were only derived from primary contexts, which could be related directly to the associated material culture. The 14C dates were modeled using Bayesian statistics that incorporate the stratigraphic information. Using this integrative approach, we date the appearance of the Philistine pottery in Tell es-Safi/Gath in the 13th century BC.

Radiocarbon dating and research into offset correction for freshwater reservoir effect were conducted at the pile-dwelling site Serteya II, located in the Dvina-Lovat' basin (northwestern Russia). Cultural layers of this site are situated underwater, hence the unique state of preservation of material culture of the 3rd millennium cal BC. 14C dating of different organic materials [wood, hazelnut (Corylus avellana), and elk bones] from this site allows their ages to be correlated and 14C age offsets caused by freshwater reservoir effects (hardwater effects) in the dating of materials such as organic crust, pottery, bones, and lake sediments to be estimated. Consideration of the late Neolithic subsistence strategy underpinning the archaeological finds from this site and analysis of lipid components in ceramic vessels, as well as the determination of 14C activity of modern aquatic and terrestrial samples, allows us to calculate the local freshwater reservoir effect and 14C age offset for charred food crusts from different ceramic vessels more precisely.

Carbon (C) and nitrogen (N) stable isotope analysis (SIA) has been used to identify the terrestrial subsidy of freshwater food webs. However, SIA fails to differentiate between the contributions of old and recently fixed terrestrial C and consequently cannot fully determine the source, age, and biochemical quality of terrestrial carbon. Natural abundance radiocarbon (Δ14C) was used to examine the age and origin of carbon in Lower Lough Erne, Northern Ireland. 14C and stable isotope values were obtained from invertebrate, algae, and fish samples, and the results indicate that terrestrial organic C is evident at all trophic levels. High winter δ15N values in calanoid zooplankton (δ15N = 24‰) relative to phytoplankton and particulate organic matter (δ15N = 6‰ and 12‰, respectively) may reflect several microbial trophic levels between terrestrial C and calanoid invertebrates. Winter and summer calanoid Δ14C values show a seasonal switch between autochthonous and terrestrial carbon sources. Fish Δ14C values indicate terrestrial support at the highest trophic levels in littoral and pelagic food webs. 14C therefore is useful in attributing the source of carbon in freshwater in addition to tracing the pathway of terrestrial carbon through the food web.

The radiocarbon activity of benthic foraminifera was investigated in surface sediments from a high deposition rate location at a depth of 1000 m in the Okhotsk Sea. Sediments were preserved and stained with Rose Bengal to identify foraminifera that contain cytoplasm. The benthic fauna at this site is dominated by large specimens of Uvigerina peregrina, and bulk samples (∼150 individuals) of stained and unstained specimens were dated. The stained sample was about 240 14C yr younger than the unstained, and the presence of bomb 14C is inferred by comparison to water column data in the nearby open North Pacific. Using new methods, multiple measurements were also made on samples of three stained and unstained individuals (as small as 7 μg C). Results are consistent with those from the bulk samples. This suggests that similar ultra-small measurements could be made at other locations to reveal the age distribution of individuals in a sediment sample in order to assess the extent of bioturbation and the presence of bomb 14C contamination.

This research is aimed at radiocarbon dating organic inclusions and lime-binder powders of mortar layers of mosaic pavements in four churches of arguable archaeological date located in northern Jordan. One mortar sample from each mosaic pavement of each church was collected, examined by thin section microscopy, and then physically pretreated by gentle crushing and dry sieving to collect lime-binder powders of different grain sizes. Charcoal samples uncovered from three samples and the CO2 gases, collected by hydrochloric acid (HCl) hydrolysis of the powders, were 14C dated using accelerator mass spectrometry (AMS). Four powders of 63–45 μm from the four samples and two powders of 45–38 μm from two samples were analyzed in order to get more precise dates and examine previous proposed models for the interpretation of the results. 14C determinations showed agreement between charcoal ages and archaeological data, while the fine lime-binder's powders, especially from the mosaic's bedding layer, produced more precise dates. Results suggest that 14C date profiles produced by HCl hydrolysis of the lime-binder powders can be clearly interpreted by the existing models.

Freshwater reservoir effects (FRE) can cause problems when radiocarbon dating human skeletal material from the Eurasian steppe. This article presents the first results of research into the extent of the FRE in the sites of Borly 4 (Eneolithic) and Shauke 1 and 8b (Early Bronze Age), northeastern Kazakhstan. Accelerator mass spectrometry (AMS) 14C dating and stable isotope (δ13C, δ15N) analysis of associated groups of samples (32 samples, 11 groups in total) demonstrate the following: (a) the diet of the humans and fauna analyzed was based on the C3 foodchain with no evidence of a C4 plant (such as millet) contribution; aquatic resources apparently were a continuous dietary feature for the humans; (b) the first 14C dates obtained for the Upper and Middle Irtysh River region attribute the Eneolithic period of the area to the 34th to 30th centuries BC, and the Early Bronze Age to the 25th to 20th centuries BC, with a ~450-yr hiatus between the two periods; (c) the maximum fish-herbivore freshwater reservoir offset observed equals 301 ± 47 14C yr. As such, 14C dates from aquatic and human samples from the area need to be interpreted with caution as they are likely to be affected by the offset (i.e. appear older). The article also discusses the effect of a sodium hydroxide (NaOH) wash on δ13C, δ15N, C:Natomic levels and collagen yields of the bone samples. Our results indicate a minor but significant effect of NaOH treatment only on C:Natomic ratios of the samples.

Four inhumations from Kivisaare and Riigiküla I settlement and burial sites were dated in the course of a project about hunter-gatherer mortuary practices in Estonia, as they were believed to belong to the Stone Age. However, these burials appear to be Early Bronze Age inhumations instead, and thus are discussed separately in the present article. These burials are the first evidence in Estonia of a long-lasting tradition of inhumations without any visible aboveground structures. As the archaeology of the Early Bronze Age in Estonia is poorly known, these four inhumations contribute immensely to our understanding about this time period. Moreover, stable isotope values show that these people had a more terrestrial subsistence strategy than Stone Age hunter-gatherers. Nevertheless, aquatic resources were probably still significant components of their diet, particularly at Kivisaare, and the radiocarbon dates could therefore be subject to significant freshwater reservoir effects. This creates ambiguity in the chronological relationship of these four individuals to burials in stone-cist graves, which are attributed to the Late Bronze Age and which appear to be associated with fully agricultural communities.

A data set of 18 radiocarbon dates from the domestic quarter and the well at Tel Tsaf provide conclusive evidence for the absolute dating of this Middle Chalcolithic site. Bayesian modeling suggests that the site was occupied in the last quarter of the 6th millennium BC and abandoned in the first quarter of the 5th millennium. The absolute dating of Tel Tsaf has further implications for the synchronization of the protohistory of the Levant. The ceramic assemblage of Tel Tsaf included delicately painted ceramic sherds (so-called Tel Tsaf ware), which are distinct from the common plain ware. Comparable motifs have been identified in ceramic assemblages of contemporary Ubaid sites such as Tell Mashnaqa, Tell Zeidan, Tell el-Abr, and Hammam et-Turkan IV in northern Mesopotamia. Tel Tsaf is a rare example of a little researched connection between the Ubaid culture and the Middle Chalcolithic of the southern Levant. The findings of Tel Tsaf expand the southwestern border of the Ubaid sphere of influence and shed new light on long-distance interaction in protohistory.

Radiocarbon natural abundances (Δ14C) are being increasingly used to trace carbon cycling in stream ecosystems. To understand the ultimate sources of carbon, we determined the stable carbon isotope ratios (δ13C) and Δ14C values of dissolved inorganic and organic carbon (DIC and DOC, respectively) and of particulate organic carbon (POC) in two small streams in central Japan, one of which flows over limestone bedrock (Seri) and the other does not (Fudoji). Investigations over four seasons revealed that the Δ14C values of the DIC (from −238‰ to −174‰ for Seri and −23‰ to +10‰ for Fudoji) were less variable than those of the other carbon fractions (DOC: from −400‰ to −138‰ for Seri and −2‰ to +103‰ for Fudoji; POC: from −164‰ to −60‰ for Seri and −55‰ to +37‰ for Fudoji). Based on mass balance calculations using the δ13C and Δ14C values, the proportions of carbon in the DIC originated from (1) atmospheric CO2 were 47% to 57% for Seri and 74% to 90% for Fudoji, (2) organic matter degradation were 29% to 35% for Seri and 4% to 21% for Fudoji, and (3) carbonate rock were 14% to 22% for Seri and 4% to 6% for Fudoji. We compared the results with previous studies that had been conducted in larger rivers and showed that in small streams, the dissolution of atmospheric CO2 and weathering of carbonate rock are more important factors in the carbon cycling than the biological degradation of organic matter.

This article presents a compilation of planktic and benthic 14C reservoir ages for the Last Glacial Maximum (LGM) and early deglacial from 11 key sites of global ocean circulation in the Atlantic and Indo-Pacific Ocean. The ages were obtained by 14C plateau tuning, a robust technique to derive both an absolute chronology for marine sediment records and a high-resolution record of changing reservoir/ventilation ages (Δ14C values) for surface and deep waters by comparing the suite of planktic 14C plateaus of a sediment record with that of the atmospheric 14C record. Results published thus far have used as atmospheric 14C reference U/Th-dated corals, the Cariaco planktic record, and speleothems. We have now used the varve-counted atmospheric 14C record of Lake Suigetsu terrestrial macrofossils to recalibrate the boundary ages and reservoir ages of the seven published records directly to an atmospheric 14C record. In addition, the results for four new cores and further planktic results for four published records are given. Main conclusions from the new compilation are the following: (1) The Suigetsu atmospheric 14C record on its varve-counted timescale reflects all 14C plateaus, their internal structures, and relative length previously identified, but implies a rise in the average 14C plateau age by 200–700 14C yr during the LGM and early deglacial times. (2) Based on different 14C ages of coeval atmospheric and planktic 14C plateaus, marine surface water Δ14C may have temporarily dropped to an equivalent of ∼0 yr in low-latitude lagoon waters, but reached >2500 14C yr both in stratified subpolar waters and in upwelled waters such as in the South China Sea. These values differ significantly from a widely assumed constant global planktic Δ14C value of 400 yr. (3) Suites of deglacial planktic Δ14C values are closely reproducible in 14C records measured at neighboring core sites. (4) Apparent deep-water 14C ventilation ages (equivalents of benthic Δ14C), deduced from the sum of planktic Δ14C and coeval benthic-planktic 14C differences, vary from 500 up to >5000 yr in LGM and deglacial ocean basins.

Many studies use radiocarbon dates on estuarine shell material to build age-depth models of sediment accumulation in estuaries in California, USA. Marine 14C ages are typically older than dates from contemporaneous terrestrial carbon and local offsets (ΔR) from the global average marine offset need to be calculated to ensure the accuracy of calibrated dates. We used accelerator mass spectrometry (AMS) 14C dating on 40 pre-1950 salt marsh snail and clam shells previously collected from four California estuaries. The average ΔR and standard deviation of 217 ± 129 14C yr is consistent with previous calculations using mixed estuarine and marine samples, although the standard deviation and resulting age uncertainty was higher for our estuarine calculations than previous studies. There was a slight but significant difference (p = 0.024) in ΔR between epifaunal snails (ΔR = 171 ± 154 14C yr) and infaunal clams (ΔR = 263 ± 77 14C yr), as well as between samples from individual estuaries. However, a closer examination of the data shows that even for the same species, at the same estuary, ΔR can vary as much as ∼500 14C yr. In some cases, the bulk of this variation occurs between samples collected by different collectors at different times, potentially indicating time dependence in carbon sources and ΔR variation. These variations could also be attributed to differences in collection location within a single estuary and resulting spatial differences in carbon sources. Intertidal specimens located in the high marsh may have lower ΔR than fully marine counterparts because of increased terrestrial 14C input. The large variations in ΔR here highlight the need for conservative chronological interpretations, as well as the assumption of wide uncertainties, when dating samples from estuarine sources.