The Nevado de Toluca is a stratovolcano located in the southwest of the Toluca Valley in central Mexico. At a height of around 4200 m there are two crater lakes: El Sol and La Luna. Since Precolumbian times, people in the surrounding valleys carried out rituals and deposited offerings into the lakes. After the Spanish conquest, these rituals were kept alive clandestinely. Currently, reminiscent of Mesoamerican rituals subsist. Due to the long duration of the ritual at the Nevado de Toluca, it is important to date the materials recovered in the underwater and terrestrial archaeological explorations. This article proposes a chronology of Prehispanic ritual activities performed in the Nevado de Toluca based on the characterization and radiocarbon (14C) dating performed to materials from the volcano’s lakes.

We present δ13C, δ15N, and δ34S measurements on archaeological human and animal bone collagen samples from a shell midden dating to the Neolithic ca. 4000–3500 cal BC, together with measurements on modern fish and shellfish. These data were used in conjunction with the Bayesian mixing model, Food Reconstruction Using Isotopic Transferred Signals (FRUITS), to reconstruct human diet at the site. We demonstrate the importance of using a geographically appropriate faunal baseline in stable isotope paleodietary studies, and suggest that Neolithic individuals at this site consumed up to ca. 21% of dietary protein from marine resources, despite stable isotope ratios that imply a wholly terrestrial diet. This marine resource consumption does not significantly shift the radiocarbon (14C) dates of these individuals, so although we must consider the use of marine resources at the site, the chronology that has previously been established is secure. The δ13C and δ15N measurements from the archaeological herbivore bone collagen indicate that it is unlikely they ate plants enriched with fertilisers such as manure or seaweed. The δ34S values reveal a sea-spray effect; therefore, in this instance, δ34S cannot be used as a dietary indicator but can be used to demonstrate the likely locality of the fauna.

Bòbila Madurell-Can Gambús is the most emblematic Neolithic cemetery in the northeastern Iberian peninsula, with a total of 179 documented pit burials. Artifacts made of exogenous raw materials, such as honey flint (southeastern France), jadeite, amphibolite, eclogite and nephrite (Alps and the Pyrenees), variscite (coast of northeastern Iberia), and even obsidian (Sardinia), have been found in the burials. The presence of these raw materials is not exclusive to this necropolis, but they have also been documented in many of the graves of this region during this period. The literature has singled out this funerary practice as the Pit Burials cultural horizon. However, until now the chronology of this funerary practice has not been fully defined, so it was difficult to explain the development of the chronology and the networks through which the materials reached northeast Iberia. New, unpublished radiocarbon (14C) dates of Bòbila Madurell-Can Gambús are presented, as well as the results of different statistical analyses and Bayesian modeling that specify its chronology. Through the contribution of new data on the chronology of Bòbila Madurell-Can Gambús new clues regarding the temporal dynamics of pit burials and the raw materials exchange networks associated with them are presented.

The volcanic mega event of the Minoan Santorini eruption constitutes a time anchor in the 2nd millennium BCE that is inherently independent of archaeology and political history. It was a geological event. Yet the dimension of time in geology is not different than in archaeology or human history. Why then does archaeological dating usually place the Minoan Santorini eruption in the 18th Dynasty around 1500 BCE, whilst radiocarbon dating of the volcanic event at Akrotiri (Thera) yielded a calibrated age of 1646–1603 cal BCE, a difference of more than a century? The crux of the problem lies apparently in the correlation between archaeological strata and political history. We present radiocarbon dates of Ashkelon Phases 10 and 11 in comparison to Tell el-Dabca and the Santorini eruption, based only on 14C dating. Tell el-Dabca Phase D/2 is slightly older than the volcanic event. But Phase D/1 or Phase C/2-3 could have witnessed the eruption. Ashkelon Phase 11 has similar radiocarbon dates as Tell el-Dabca Phases E/2, E/1 and D/3, all being significantly older than the Minoan eruption. It seems that the duration of Ashkelon Phase 10 includes the temporal occurrence of the Minoan Santorini eruption within the Second Intermediate Period.

This article addresses chronological problems about archaeological sites traditionally associated with the Belén culture from Hualfín Valley (Catamarca, Argentina), analyzing background research, radiocarbon dates obtained by A Rex González before 1970, and 14C dates made since 1996. First, we critically review the chronological sequence built by González for Belén sites, which include the Late period (AD 1100–1480) and Inca period (AD 1480–1536), subdivided into three phases. Methodological problems that could affect results of the first 14C dates are discussed. Based on this review, we present new 14C dating considering extraction contexts, types of samples, calibration curve data used, the laboratory where each date was obtained, and their methods of measuring, characteristics of sites of origin, and associated archaeological material. Finally, using calibrated ranges and Bayesian models, we suggest groups of events that would correspond to different times in the history of late occupations in the valley.

Two radiocarbon excursions (AD 774–775 and AD 993–994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C increase in the IntCal data is large. We analyzed four periods every other year (2479–2455 BC, 4055–4031 BC, 4465–4441 BC, and 4689–4681 BC), and found no anomalous 14C excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

Since the AD 775 and AD 994 Δ14C peak (henceforth M12) was first measured by Miyake et al. (2012, 2013), several possible production mechanisms for these spike have been suggested, but the work of Mekhaldi et al. (2015) shows that a very soft energy spectrum was involved, implying that a strong solar energetic particle (SEP) event (or series of events) was responsible. Here we present Δ14C values from AD 721–820 Sequoiadendron giganteum annual tree-ring samples from Sequoia National Park in California, USA, together with Δ14C in German oak from 650–670 BC. The AD 721–820 measurements confirm that a sharp Δ14C peak exists at AD 775, with a peak height of approximately 15‰ and show that this spike was preceded by several decades of rapidly decreasing Δ14C. A sharp peak is also present at 660 BC, with a peak height of about 10‰, and published data (Reimer et al. 2013) indicate that it too was preceded by a multi-decadal Δ14C decrease, suggesting that solar activity was very strong just prior to both Δ14C peaks and may be causally related. During periods of strong solar activity there is increased probability for coronal mass ejection (CME) events that can subject the Earth’s atmosphere to high fluencies of solar energetic particles (SEPs). Periods of high solar activity (such as one in October–November 2003) can also often include many large, fast CMEs increasing the probability of geomagnetic storms. In this paper we suggest that the combination of large SEP events and elevated geomagnetic activity can lead to enhanced production of 14C and other cosmogenic isotopes by increasing the area of the atmosphere that is irradiated by high solar energetic particles.

At INFN-LABEC (Florence, Italy), a new pretreatment for radiocarbon dating based on chloroform has been recently set up. This method aims to remove the synthetic resins used for artwork restoration, which otherwise could alter the original 14C content. The present study characterizes the efficiency of the process when applied to wood. We have verified whether the effectiveness of the pretreatment depends on the number of extractions in chloroform. We prepared samples by applying different volumes of Paraloid B-72®, one of the most widespread products used in restoration, on poplar wood of known age. Contaminated samples were artificially aged in a climatic chamber. A fraction from each sample was collected before any treatment and after respectively 1, 2, 3, and 4 extractions in chloroform, and 14C dating by AMS, the resin appears to be already removed after the first two extractions. Furthermore, the extracted mixtures of chloroform and possible removed Paraloid were measured by FTIR spectroscopy, the results of which confirmed the 14C results. The efficiency of the pretreatment was also verified on historical wooden materials that had been previously restored. In these cases, a higher number of extractions is required, suggesting a careful approach when dealing with “real” artworks.

Air pollution in Mexico City, which has more than 22 million inhabitants, continues to be one of the main environmental issues. Aerosol samples (PM10) collected in Mexico City and the city of Cuernavaca (a clean reference site) have been characterized using different techniques. This multifaceted approach addresses the source apportionment of the carbonaceous matter in PM10, as well as the airborne elements and ions. Accelerator mass spectrometry (AMS) radiocarbon analysis of total carbon, X-ray fluorescence (XRF), and ion chromatography were performed on aerosols collected at three sites in Mexico City and one site in Cuernavaca, during 2 months of the cold-dry season (November–December) in 2012. New results obtained for Mexico City are compared with previous reports. Average levels of PM10 were higher in Mexico City sites (43.3–60.8 μg/m3) than in Cuernavaca (32.2 μg/m3). According to the material balance, PM10 collected in Mexico City had a lower contribution of crustal material (31.2–36.8%) than Cuernavaca (46.9%). Average contributions of particulate carbonaceous matter to PM10 were similar in both cities, but much higher contributions of mineral salts, trace elements, and ions were observed in Mexico City in comparison to Cuernavaca. Total organic carbon (OC) and elemental carbon (EC) contents were higher in aerosols from Mexico City than those from Cuernavaca. The temporal variation results showed that within all locations studied the OC concentration was high compared to the EC. Results from a theoretical calculation of fossil carbon (FC) and biogenic carbon (BC) concentrations showed that FC and BC levels depend on the site: at Mexico City sites, FC was equal or higher than BC. At Cuernavaca, BC was always higher than FC.

In recent decades, the radiocarbon method has frequently been used for dating organic admixtures in pottery. This method is useful for dating the Late Stone Age cultures in eastern Europe due to the poor availability of other organic materials. On the contrary, Bronze Age sites offer a great variety of organic sources, including remains of wooden structures, charcoal, and human and animal bones. This paper analyzes the 14C dates obtained on bones and pottery from six Bronze Age sites in order to determine the feasibility of 14C pottery dating for this particular period. Bronze Age pottery is made of silty clay containing organic matter, which can comprise older material. Therefore, 14С dates obtained on bones, wood, or charcoal are more representative. This paper analyzes the 14C dates obtained on bones and pottery from six Bronze Age sites. Based on this limited study, the authors conclude that dating of pottery from the Bronze Age is controversial and can result in much older dates. We argue this method is acceptable only if no other organic materials are available.

The Institut Français d’Archéologie Orientale (IFAO) in Cairo is one of the major French research centers abroad. It is placed under the aegis of the French Ministry of Higher Education and Research and manages an archaeometry department that features laboratories for three units of research: conservation, material studies, and radiocarbon (14C). The 14C laboratory was founded in 2006 to offer the possibility of 14C dating in Egypt. It is totally devoted to archaeological issues, uses the conventional liquid scintillation counting (LSC) method, and is equipped with two benzene synthesis lines. This paper reports on the performances and quality-control procedures of the IFAO 14C laboratory, both from the perspective of the chemical syntheses and from the radiometric measurements (background dispersion, standards, intercomparison programs). It shows how this lab occupies a privileged position to develop interdisciplinary studies of Egyptian chronology and to offer high-standard competencies to the IFAO scientific research programs. Finally, it raises the question of the future perspectives of the laboratory.

The Monastery of Hosios Loukas is situated at an altitude of 430 m (38°23′43.12′′N, 22°44′48.22′′E) in the western foothills of Mount Helikon, near the village of Steiri, Boeotia, Greece. It is one of the most important monuments of Middle Byzantine art and architecture and has been recognized by UNESCO as a World Heritage Site. Information varies concerning the construction date of the magnificent church to house the Hosios Loukas relics. Moreover, little is known about the time when the rest of the monastic complex was built. This paper aims to shed light on these chronological questions. For this purpose, 15 wood samples, originating from the outermost rings of the wooden timber preserved from the initial scaffolding of the church and its four supporting buttresses and another two from the wooden gate of the monastery, were radiocarbon (14C) dated using the conventional gas-counting technique. Our results show that the church was built in the beginning of the 11th century. The four buttresses were built in at least two phases, during the 15th through 19th centuries, and the monastery gate may be also attributed to the 19th century.

This study evaluates the radiocarbon dating of ceramic samples from Tupiguarani sites in Brazil, a settlement type dating up to 3000 cal BP. In this work, residues from ceramic samples from four archaeological sites in Rio de Janeiro (Morro Grande, Serrano, Barba Couto, and Bananeiras) were analyzed. In order to identify the most suitable sample preparation protocols, the humic fraction was isolated from the bulk material at the Oxford Radiocarbon Accelerator Unit (ORAU), whereas the acid-base-acid (ABA) residue fraction method was applied at the Radiocarbon Laboratory of the Fluminense Federal University (LAC-UFF). The dating results were compared to the current knowledge about the occupational periods of the sites. For the Morro Grande site, the results of humic and ABA residue fractions show a difference of more than 1500 yr. For the Serrano site, the 14C ages obtained from the two pretreatments are identical, and as with the Barba Couto and Bananeiras sites, indicate an occupation during the Brazilian colonial period of the 16th century AD and are compatible with the archaeological data.

Beppu Bay is located on east-central Kyushu, southwest Japan, and is characterized by hydrothermal activity, tectonic deformation, and recent volcanism under the influence of convergence of the Philippine Sea plate. This area, occupying the western portion of an arc-bisecting dextral fault system, is a tectonic depression that has existed since ca. 5 Ma. Sedimentary facies, mollusk assemblages, and radiocarbon (14C) ages of 25 terrestrial plant fragments and 16 marine carbonate shells from a 70-m drill core were determined to estimate the activity of the Funai Fault, which consists of normal faults along the southern margin of the tectonic basin. Based on the analysis, six sedimentary facies, namely braided river channel, estuary, prodelta, delta front, delta plain, and artificial soil, were identified. The vertical slip rate was calculated as 2.6–2.7 mm/yr based on displacements of the braided river channel sediments of the last glacial period and the base of Kikai-Akayoya tephra in the Holocene highstand sediments of this area. Reservoir ages during 6180–10,410 cal BP were determined from marine shell and terrestrial plant pairs from the sediments of the estuary, prodelta and delta front facies, and were correlated with values from a northern coast of Kyushu and the Korean Peninsula.

The chronology of the Inca Empire has traditionally relied on ethnohistoric dates, which suggest that a northern expansion into modern Ecuador began in AD 1463 and a southern expansion into modern Argentina began in AD 1471. We test the validity of these dates with two Bayesian models, which show that the ethnohistoric dates are incorrect and that the southern expansion began before the northern one. The first model of seven dates shows that the site of Chamical, Ecuador, was first occupied cal AD 1410–1480 (95% probability) and has a high probability of being built prior to the ethnohistoric date. The second is an outlier model of 26 14C dates and 19 thermoluminescence (TL) dates from 10 sites along the empire’s southeastern limit in northwestern Mendoza, Argentina. Here, the Inca occupation began cal AD 1350–1440 (95% probability), also earlier than the ethnohistoric date. The model also suggests that the Inca occupation of Mendoza lasted 70–230 yr (95% probability), longer than previously thought, which calls for new perspectives on the timing and nature of Inca conquests and relationships with local groups. Based on these results, we argue it is time to abandon the traditional chronology in favor of Inca chronologies based on Bayesian models.

The Neolithic in Britain saw the first appearance of domestic plant and animal resources, pottery, polished stone axes, monuments, and new house structures. With the introduction of domesticates and associated subsistence strategies, the Neolithic represents a significant change in human–environment interaction. Other changes have been observed in the palynological record of Britain in the early fourth millennium cal BC, including the elm decline, and archaeologists and paleobotanists have long discussed the degree of human involvement in this. This paper presents the first Bayesian statistical analysis of the elm decline using the case study of the east of Yorkshire and Humberside and key sites in west Yorkshire, and evidence for the last hunter-gatherer Mesolithic material culture and the first Neolithic material culture record. This region is critical because it is the only area of Britain and Ireland where we have robust and accurate published estimates for the timing of the latest Mesolithic activity and timing for the earliest Neolithic activity. Unpacking this perceived chronological correlation between the elm decline and the start of the Neolithic is critical to understanding the scale of human–environment modification at this time, and the nature of the first Neolithic societies in Britain.

The regional component (∆R) of the marine reservoir effect (MRE), which is crucial for the accurate calibration of radiocarbon ages of marine-influenced samples, was determined for the Cuban northwestern coast. Fifteen different locations were studied by 14C dating of pre-bomb known-age marine shells specimens of bivalves and gastropods from the Felipe Poey Museum collection. Accelerator mass spectrometry (AMS) 14C measurements were performed at the Radiocarbon Laboratory of the Universidade Federal Fluminense (LAC-UFF) and mean ΔR values were estimated. The distribution of results indicates ∆R values from −46±38 to 140±52 14C yr and a possible pattern related to the position along the coast and ocean dynamics. We present both mean values for each region and a general ∆R of 28±13 14C yr for the northwestern coast of Cuba.

The Dangoor REsearch Accelerator Mass Spectrometer (D-REAMS) is a dedicated carbon-only AMS system, built by National Electrostatics Corporation (NEC). It is based on the 1.5SDH Pelletron, operating at 460 keV. The machine was installed at the Weizmann Institute of Science, Rehovot, Israel, in January–February 2013, and passed the acceptance test on March 2013. Since then, over 4500 samples have been successfully measured. Here, we present the results of an intercomparison experiment, done in collaboration with the Vienna Environmental Research Accelerator (VERA), and some typical operation parameters and measurement values of the new AMS system.

One of the most impressive structures in Jerusalem’s ancient landscape is the tower that was built to surround and protect the Gihon Spring, Jerusalem’s perennial water source. The structure, first discovered by Reich and Shukron (2004), encompasses the cave in which the spring sprouts from, with walls 7 m thick built of large boulders. The Spring Tower, along with the other features relating to it, were all attributed to the Middle Bronze Age II, based on their architectural and stratigraphical relationship, the type of architecture, and the pottery found. In the continued excavations carried out by the Israel Antiquities Authority along the outer, eastern face of the Spring Tower, it was noted that at least the northeast side of the tower was not built on bedrock, but rather on layers of sediment, which were sealed by the massive boulders at the base of the tower. In order to provide an absolute dating for the structure, two sections were sampled for radiocarbon (14C) dating beneath the foundation stones at two locations. Scenarios for the construction of the tower during Middle Bronze Age (MB) and Iron Age II are considered, based on the new 14C data, yielding a series of dates, the latest of which falls in the terminal phases of the 9th century BCE, alongside previous excavation data.

Hikobe House is an important cultural property located in Gunma prefecture. It is one of the oldest manor houses in the Kanto region of Japan. The age of the Hikobe House has up to now been uncertain. There are no architectural records or memorandum tags that indicate when the Hikobe House was built. The living room of the Hikobe House has a style of the latter half of the 17th century, while the guest rooms exhibit a style more typical of the 16th century. So, architectural historians did not agree when the house was built. The wooden materials of the Hikobe House (zelkova, cherry tree, and Japanese red pine) are species that are not well suited to dendrochronology. Thus we investigated the materials of the Hikobe House using the radiocarbon (14C) dating method. Using both the 14C wiggle-match dating method on short tree-ring sequences and observations of remodeling traces of the materials, we were able to establish a credible age of Hikobe House as dating from the late 17th century.