The most widely used dating techniques in quaternary research are the radiocarbon (14C) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for 14C dating. In these cases, 14C dating of bulk sediment may be used as a last resort. The major aim of the present study was to determine the reliability and limitations of the different fractions of the soil organic carbon (SOC) 14C ages in the Nyírség blown-sand study area, in Hungary. Therefore, the low- and high-temperature combustions of SOC (LT-SOC and HT-SOC) 14C age of fossil soils were compared with the charcoal ages from the same fossil soil layer, and their (LT-SOC, HT-SOC, and charcoal) age reliability was verified independently by applying OSL to the quartz fraction of the sediment samples. The 14C data show variable agreement with OSL ages. Charcoal fragments were collected from some of the best material for 14C dating and their ages are in agreement with the LT and HT-SOC 14C ages and OSL data. The 14C age LT-SOC gives a reliable, credible ages, which were confirmed by independent OSL measurements. If buried soils do not contain any other macroscopic remnants for 14C dating, the LT-SOC 14C ages can be used, in the case of the Nyírség study area. The LT-SOC, which is the younger fraction of the soil organic carbon, may be considered to represent the burial time of the fossil soil layer. The HT-SOC 14C ages are sometimes unrealistically older than expected and cannot be considered to be reliable.

Sixty-two 14C dates are analyzed in combination with a recently established local floating tree-ring sequence for the Early Neolithic site of La Draga (Banyoles, northeast Iberian Peninsula). Archaeological data, radiometric and dendrochronological dates, as well as sedimentary and micro-stratigraphical information are used to build a Bayesian chronological model, using the ChronoModel 2.0 and OxCal 4.4 computer programs, and IntCal 2020 calibration curve. The dendrochronological sequence is analyzed, and partially fixed to the calendrical scale using a wiggle-matching approach. Depositional events and the general stratigraphic sequence are expressed in expanded Harris Matrix diagrams and ordered in a temporal sequence using Allen Algebra. Post-depositional processes affecting the stratigraphic sequence are related both to the phreatic water level and the contemporaneous lakeshore. The most probable chronological model suggests two main Neolithic occupations, that can be divided into no less than three different “phases,” including the construction, use and repair of the foundational wooden platforms, as well as evidence for later constructions after the reorganization of the ground surface using travertine slabs. The chronological model is discussed considering both the modern debate on the Climatic oscillations during the period 8000–4800 cal BC, and the origins of the Early Neolithic in the western Mediterranean region.

Wetland sediments are valuable archives of environmental change but can be challenging to date. Terrestrial macrofossils are often sparse, resulting in radiocarbon (14C) dating of less desirable organic fractions. An alternative approach for capturing changes in atmospheric 14C is the use of terrestrial microfossils. We 14C date pollen microfossils from two Australian wetland sediment sequences and compare these to ages from other sediment fractions (n = 56). For the Holocene Lake Werri Berri record, pollen 14C ages are consistent with 14C ages on bulk sediment and humic acids (n = 14), whilst Stable Polycyclic Aromatic Carbon (SPAC) 14C ages (n = 4) are significantly younger. For Welsby Lagoon, pollen concentrate 14C ages (n = 21) provide a stratigraphically coherent sequence back to 50 ka BP. 14C ages from humic acid and >100 µm fractions (n = 13) are inconsistent, and often substantially younger than pollen ages. Our comparison of Bayesian age-depth models, developed in Oxcal, Bacon and Undatable, highlight the strengths and weaknesses of the different programs for straightforward and more complex chrono-stratigraphic records. All models display broad similarities but differences in modeled age-uncertainty, particularly when age constraints are sparse. Intensive dating of wetland sequences improves the identification of outliers and generation of robust age models, regardless of program used.

Plasma oxidation for 14C sampling utilizes low-pressure (133 Pa), low-energy (<50 W), and low- temperature (<50°C) Ar- and O2-plasmas generating CO2 for AMS dating. O2-plasmas on empty chambers remove organic contamination. When clean, a new specimen is inserted and Ar-plasmas dislodge adsorbed atmospheric CO2 from surfaces. Finally, O2-plasmas oxidize organic materials to CO2 for AMS analysis. During some Ar-plasmas we observed anomalous pressure increases and unexpectedly high CO2. Residual gas analysis detected water, hydrogen and oxygen species with Ar and CO2 indicating water plasmas that produced excited oxygen species that prematurely oxidized specimen organic matter. Evolution of excess CO2 during Ar cleaning compromises the ability to affirm that atmospheric CO2 was removed. Standards, TIRI Belfast Pine and VIRI I Whalebone, were dated to determine whether water-induced oxidation was a confounding influence in dating. TIRI wood was sampled twice, once a water-soaked specimen in an Ar plasma and once with water-vapor-plasma only. The TIRI dates agreed with six earlier dates on usual specimens. A colloidal extract from VIRI I whale bone was also sampled and dated twice using both water–plasma oxidation in an Ar-plasma and in an O2-plasma. Dating agreement suggests that water plasmas do not pose undue risks of contamination.

Hessel de Vries contributed to radiocarbon (14C) dating for only one short decade. Yet, his development of proportional CO2 counting greatly facilitated 14C measurements, improved their reproducibility, and lowered both the amount of carbon needed for a measurement and the 14C detection limit by at least a factor ten. Validating Libby’s 14C method by checking its basic assumptions with improved sensitivity, de Vries documented relatively minor violations. Natural variations in atmospheric 14C concentrations, found in tree rings, marked the start of 14C tree-ring calibration. Variable differences in 14C concentration between the atmosphere and aquatic reservoirs revealed reservoir ages, leading to further studies. De Vries applied analogue modeling to gain a better understanding of the influence of cosmogenic 14C production and the global carbon cycle, inclusive CO2 exchange across the air-water boundary, on atmospheric 14C concentrations. In close collaboration with colleagues in archaeology and geology, de Vries documented climate fluctuations and archaeological developments over the last 50,000+ years and placed them on a common 14C time scale.

Chronological and stratigraphic frameworks are of the utmost importance for Upper Paleolithic archaeology, physical anthropology, and ecology. Wide ranging radiocarbon (14C) dates were previously obtained for the Sungir burial complex in the central part of European Russia, which is well-known as the richest funeral Paleolithic assemblage in the world yet recorded. The major problem was the contamination caused by consolidants used during the recovery of human bones in the 1960s. The stratigraphy and spatial structure of the Sungir site were also not well understood previously. New radiocarbon and stable isotope data are generated for the Sungir burials. While some dates were younger due to incomplete removal of contamination, the XAD 14C age on S-1 burial (ca. 29,780 BP) was found to be statistically the same as the previously performed HYP 14C age for this burial (ca. 28,890 BP). Four animal bones found in cultural layer below the burial date to ca. 28,800–30,140 BP, suggesting that both this layer and human burials date to roughly this age range. Narrowing these ages further is difficult considering the larger errors of the 14C dates. This shows that future research attempting to 14C date material excavated many years ago needs to eliminate potential contamination from consolidants through analyses such as FTIR, prior to 14C dating. The chronology and stratigraphy of Sungir do not contradict to correlation of its lithic artifacts with the Streletskian assemblage as the East European variant of the Final Szeletian technocomplex (Early Upper Paleolithic).

A concise review is presented of applying 14C produced in the atmospheric nuclear weapons testing program (1950 to 1963), subsequently forming the so-called 14C bomb peak. In order to convey the versatility of this unique isotope signal, selected applications from a variety of different fields are discussed touching on environmental, archaeological, biological, and forensic issues. A comprehensive list of references is supplied for in-depth studies of the respective fields.

Direct atmospheric 14CO2 measurements began in New Zealand in 1954, initially to improve 14C as a dating tool, but quickly evolving into a method for understanding the carbon cycle. These early 14CO2 measurements immediately demonstrated the existence of an “Atom Bomb Effect,” as well as an “Industrial Effect.” These two gigantic tracer experiments have been utilized via 14CO2 measurements over the years to produce a wealth of knowledge in multiple research fields including atmospheric carbon cycle research, oceanography, soil science, and aging of post-bomb materials.

The importance of studying the radiocarbon content of dissolved inorganic carbon (DI14C) in the oceans has been recognized for decades. Starting with the GEOSECS program in the 1970s, 14C sampling has been a part of most global survey programs. Early results were used to study air-sea gas exchange while the more recent results are critical for helping calibrate ocean general circulation models used to study the effects of climate change. Here we summarize the major programs and discuss some of the important insights the results are starting to provide.

Vast burial fields, some with hundreds of burials, categorize the southern Levant’s Intermediate Bronze Age period (IBA). This phenomenon contrasts with a limited number of burials found from the preceding Early Bronze III period. This paper presents the first radiocarbon dating research of sampled bones from shaft tombs from five IBA burial sites across Israel: Yehud, Jebel Qaaqir, Sheikh-Danon, Hazorea, and Kefar-Veradim. Prescreening methods, including Fourier transform infrared analysis, were applied to identify best-preserved collagen in archaeological bones for radiocarbon dating. Overall, the measured date ranges cover the IBA timeline, supporting the observation that the IBA signature shaft tombs are a fundamental tradition of the IBA culture, at least in Israel. A single IBA shaft tomb at Jebel Qaaqir which contained remains of multiple humans, supplied different dates for various people, spanning over a few hundred years. These results suggest a tribal or family-oriented IBA community with a long-lasting tradition reflected in centuries of collective burial practices.

In this paper, we analyze the background activity of anthropogenic radionuclides (14C, 3H, 137Cs, and 239,240Pu), emphasizing 14C content, in terrestrial and aquatic ecosystems in the Lithuanian border region before the commissioning of a new nuclear power plant in Belarus (BelNPP). In terrestrial samples, the 14C concentration varied insignificantly—from 98.6 ± 0.7 to 102.2 ± 0.8 pMC, which is close to the 14C level in atmospheric CO2. In aquatic samples, the 14C concentration varied within wide limits from 76.9 ± 0.7 to 99.6 ± 0.6 pMC, depending on the ecological group of macrophytes. Various ecological groups of macrophytes have experienced the influence of a freshwater reservoir effect. This lowest 14C content in submerged macrophyte species, within the limits of uncertainty, was very close to the specific activity of 14C in DIC (78.6 ± 0.6 pMC) in the water of the Neris River. The background 14C values, together with the data on 3H, 137Cs and 239,240Pu obtained in this study, can be used in the future to assess the contribution of the BelNPP conventional radioactive effluents to the levels of 14C and other radionuclides in terrestrial and aquatic ecosystems of the transboundary region of Belarus and Lithuania.

We present the first Bayesian 14C modeling based on AMS ages from stratified sediments representing continuous occupation across the Early Bronze III/IV interface in the Southern Levant. This new high-precision modeling incorporates 12 calibrated AMS ages from Khirbat Iskandar Area C using OxCal 4.4.4 and the IntCal 20 calibration curve to specify the EB III/IV transition at or slightly before 2500 cal BCE. Our results contribute to the continuing emergence of a high chronology for the Levantine Early Bronze Age, which shifts the end of EB III 200–300 years earlier than the traditional time frame and increases the length of EB IV to about 500 years. Data from Khirbat Iskandar also help direct greater attention to the importance of sedentary communities through EB IV, in contrast to the traditional emphasis on non-sedentary pastoral encampments and cemeteries. Modeling of AMS data from Khirbat Iskandar bolsters the ongoing revision of Early Bronze Age Levantine chronology and its growing interpretive independence from Egyptian history and contributes particularly to re-examination of the EB III/IV nexus in the Southern Levant.

This paper presents new results of radiocarbon (14C) ages from archaeological sites in northern Igboland. The study was designed to shed more light on early human occupation and activities in the study area based on sediments from cave and iron-smelting sites. The approach consisted of ethnographic, archaeological, palynological, and slag analyses; these were complemented with 14C dates. The technology adopted as well as the paleoenvironmental conditions that prevailed during the period of human settlement in both sites was revealed. These data, complemented by 14C dates, highlight the human behavioral and subsistence patterns within the region and are comparable to those from similar sites in southeastern Nigeria.

Freshwater reservoir ages and a potential freshwater diet effect are examined for Manitoba (Canada), using paired samples of contemporaneous terrestrial, freshwater, and omnivore-diet species (Homo sapiens, Gavia sp.). The freshwater diet effect (n=4) varies from 220 to 370 14C years. The FRE (n=12) is temporally variable, with a median of 230 14C years and values up to 880 14C years (or more). Understanding the FRE is important for geologists who reconstruct the postglacial history of an area. It is also important for archaeologists who rely on 14C dating to develop cultural histories, as inhabitants of the Canadian boreal forest have relied upon freshwater resources as a part of their diet. An analysis of the δ13C on 93 freshwater mollusk samples from 11 species demonstrates significant variability, which highlights the difficulty in assigning an “assumed” fractionation correction.

This paper establishes the chronology of the El Pozuelo megalithic complex and discusses it in the context of other dolmens that have been dated in the southwest of the Iberian Peninsula. The working methodology combines the study of the stratigraphy and architectural sequence with the Bayesian modeling of the 27 AMS 14C dates obtained for charcoal samples from the four monuments in the Los Llanetes cluster. The most significant chronological results (at 68% probability) are (a) the antiquity and long duration of the megalithic sites, in which several monumental structures succeeded one another ca. 3970–1980 cal BC; (b) the existences of different temporalities in the Late-Final Neolithic dolmens: simple chambers (3970–3760 cal BC), elongated chambers (3790–3620 cal BC) and multiple chambers (3660–3260 cal BC; (c) the continuity of activity during the Copper Age (2980–2580 and 2530–2180 cal BC); and (d) the permanence of megalithism in the Early Bronze Age, through the presence of terraced enclosures with circular platforms ca. 2230–1940 cal BC. This diachronic sequence and the contextualized analysis of the 152 available radiocarbon dates (27 new, 125 published) supports the establishment of the temporal dynamics of megalithism in the Iberian southwest, introducing key aspects on the emergence, span, and rebuilding of the different dolmens (passage graves, simple chambers, elongated chambers, and multiple chambers) and establishing the phases of activity and reuse of the different architectural types.