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Quantifying the local marine reservoir age (ΔR) and its change over time is critical for precise radiocarbon calibration of marine samples and for the study of the ocean carbon cycle. ΔR values are scarce for the African coast facing the Indian Ocean, and the few values available were obtained from pre-bomb shells collected during the 19th century. Here, the ΔR value for calibrated year 1110 ± 25 (1σ) CE was reconstructed from radiocarbon dating and Bayesian analysis of marine and terrestrial materials coexisting in a tsunami deposit discovered in Pangani Bay (Tanzania, western Indian Ocean coast). The reconstructed ΔR of –8 ± 40 (1σ, n = 3) is similar to pre-bomb regional estimates and provides new information to investigate regional ΔR change over time. The Bayesian analysis of the dated samples revises the age of the tsunami event found in Pangani Bay to 1064–1157 cal CE (95.4% confidence level) or 1110 ± 25 (1σ) cal CE, about one century younger compared to the previous estimate. Our results indicate that the new ΔR value and the proposed calibration approach can be used to refine existing chronologies in the region, with implications for paleo-environmental reconstructions and archaeological studies of Early Swahili societies.

Shells from Neolithic shell midden sites have been routinely dated in Korea, but they have not been calibrated based on the correction values (ΔR) for the marine reservoir effect (MRE). A lack of proper calibration has left dates on shells incomparable to those on terrestrial samples, and thus unusable in building the chronological sequence of shell middens. Here, we report the two new ΔR values of a pre-bomb (pre-1950) blue mussel from the south coast. We applied the two new and the two previously reported ΔR values to the three dates on marine shells from the Bibongri shell midden in southeastern Korea. Our ΔR adjusted calibration and the comparison to dates on charcoal and bone remains clarify an ambiguity in the stratigraphy and the Early Neolithic chronology at Bibongri. Our contribution is to provide the ΔR values that can be further applied to other Neolithic shell middens along the south coast.

The aim of the comment is to address the misrepresentations of our work on the Neolithic transitions that are found in a recent article by Manen and coauthors in Radiocarbon. There are a fair number of them as indicated in the comment. The purpose of the comment is (1) to set the record straight, (2) to clarify several misconceptions that have persisted in the literature for some time, and (3) to comment briefly on the convergence between our own recent regional modeling of the spread of early farming along the north coast of the West Mediterranean and the position currently held by Manen and coauthors.

The following paper presents the results of radiocarbon (14C) dating of Middle Bronze Age (MB) contexts in Jerusalem. The dates, sampled with microarchaeology methods from three different locations along the eastern slopes of the city’s ancient core, reveal that Jerusalem was initially settled in the early phases of the period, with public architecture first appearing in the beginning of the 19th century BC and continued to develop until the 17th century BC. At that time, a curious gap in settlement is noted until the 16th century BC, when the site is resettled. The construction of this phase continued into the early 15th century BC. The dates presented are discussed in both the site-level, as well as their far-reaching implications regarding MB regional chronology. It is suggested here that the high chronology, dating the Middle Bronze Age between 2000 and 1600 BC is difficult to reconcile with dates from many sites. In contrast, a more localized chronology should be adopted, with the Middle Bronze Age continuing into the early 15th century BC in certain parts of the southern Levant, such as the region of Jerusalem.

In hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

An international consortium of radiocarbon (14C) laboratories was established to date the origin of the St. George’s Rotunda in Nitrianska Blatnica (Slovakia), because its age was not well established in previous investigations. Altogether, 20 samples of wood, charcoal, mortar and plaster were analyzed. The 14C results obtained from the different laboratories as well as between the different sample types were in good agreement, resulting in a 14C calibrated age of 783–880 AD (94.2% probability) for the Rotunda. Although the 14C results have very good precision, the specific plateau-shape of the calibration curve in this period caused the wide range of the calibrated age. The probability distribution from OxCal calibration shows, however, that about 86% of the probability distribution lies in the period before 863 AD, implying that the Rotunda could have been constructed before the arrival of Constantine (St. Cyril) and St. Methodius to Great Moravia. The Rotunda thus probably represents the oldest standing purpose-built Christian church in the eastern part of Central Europe., Radiocarbon, 63 (3), ISSN:0033-8222

The analysis of processing standards alongside samples for quality assurance in radiocarbon (14C) analyses is critical. Ideally, these standards should be similar both in nature and age to unknown samples. A new compound-specific approach was developed at the University of Bristol for dating pottery vessels using palmitic and stearic fatty acids extracted from within the clay matrix and isolated by preparative capillary gas chromatography. Obtaining suitable potsherds for use as processing standards in such analyses is not feasible, so we suggest that bog butter represents an ideal material for such purposes. We sampled ca. 450 g from two bog butter specimens and homogenized them by melting. We verified the homogeneity of both specimens by characterization of their lipid composition, δ13C values of individual lipids, and both bulk- and compound-specific radiocarbon analyses on 10 sub-samples of each bog butter specimen. The weighted means of all 14C measurements on the bog butter standards are 3777 ± 4 BP (IB33) and 338 ± 3 BP (IB38), thereby providing age-relevant standards for archaeological and historical fatty acids and ensuring the accuracy of radiocarbon determinations of lipids using a compound-specific approach. These new secondary standards will be subjected to an intercomparison exercise to provide robust consensus values.

Radiocarbon (14C) dating was applied to the Neolithic open-air, flat-extended settlement at Revenia-Korinos in Pieria, North Greece. The samples came from the earlier habitation period of the settlement, characterized by more than 100 pits that vary significantly in shape and dimensions, some of them being identified as subterranean or semi-subterranean pit dwellings. It is suggested that the fills of the pits were the result of secondary, structured refuse deposition, except for pits that preserve their habitational use, according to stratigraphic data. The 14C results confirm that Revenia is among the earliest Neolithic settlements in North Greece and the Aegean in general. The initial phase of habitation is dated at around 6600/6550 BC comparable only to two other EN sites in North Greece. Habitation intensified at around 6460/6430 BC, accompanied by a shift in pottery style. This phase lasts until 6200/6100 BC when the pit habitation mode is followed by above-ground, rectangular post-framed structures. The dates of the human burials from Revenia also identify them as among the earliest Neolithic burials in Greece. Finally, the radiocarbon dates proved very useful for sequencing the chronological use of the pits and the excavated area in general.

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 a14C 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.

Jacob’s Well, located in modern city of Nablus and ancient Shechem (Tall Balata) in the northern West Bank of Palestine, attracts modern day tourists and pilgrims. It is found in the eastern suburbs of the city. Since 333 AD, pilgrims have been writing accounts of the well, and it has been venerated by both Christian and Jewish communities throughout its history. It is believed to be the well referred to in the New Testament, where Jesus conversed with a Samaritan woman, the orthodox saint, Photini. It now forms the central feature in the crypt of the St Photini Greek Orthodox church in the walled grounds of a monastery. In order to gain more information on the chronology of the site, we analyzed human skeletal remains found at the site in 1997. These consist of three skulls and a femur. One of the skulls was found in a sarcophagus alongside the church and the two other skulls and a femur were found in a burial ground alongside the monastery, north of the church, over which a room has now been built. Radiocarbon analysis reveals that the remains date to four historical periods or events: the early Christian period, before structural additions to the well by Constantine the Great in the fourth century; the Samaritan Revolts (AD 529 and 556), the Sassanid Invasion (AD 614–628), and Abbasid rule (AD 750–1258). Dating of one skull suggests it may have been that of Germanus, a fourth century bishop of Nablus, and that there may have been a very early structure, shrine, or burial chamber at the site before the fourth century. We provide contextual information based on historical and contemporary literature.

The Nekselø Wickerwork provides an unusually solid estimate on the marine reservoir age in the Holocene. The basis for this result is a 5200-year-old fish weir, built of hazel wood with a brief biological age of its own. Oysters settled on this construction. They had lived only for a short number of years when the fence capsized and was covered in mud and the mollusks suffocated. Based on the difference in radiocarbon (14C) age between accelerator mass spectrometry (AMS) samples of oyster shells and wood, respectively, the marine reservoir age for this site is estimated to 273 ± 18 14C years. Re-evaluations of previously produced data from geological and archaeological sites of Holocene date in the Danish archipelago indicate marine reservoir ages in the same order as that of the Wickerwork. Consequently, we recommend the use of the new value, rather than the ca. 400 14C years hitherto favored, when correcting for the dietary induced reservoir effect in radiocarbon dates of humans and animals from the Late Mesolithic and Early Neolithic periods of this region.

The Mexico City Basin has had exceptional plant and animal diversity since ancient times due to its varied orography and benign climate. This environment attracted diverse human groups, from hunter-gatherers to one of the most influential pre-Hispanic cultures of Mesoamerica: the Mexica, also known as the Aztec. The subsoil of Mexico City hides a rich and varied cultural heritage. The Archaeological Rescue Department works to preserve cultural heritage, review archaeological studies, and expand archaeological information with new findings. We report on archaeological rescue works carried out at two sites in the Mexico City Basin prior to the beginning of new construction projects. The first one is the Reforma Hidalgo Complex Office in Teocaltitlán, one of the neighborhoods of ancient Mexica City, Mexico-Tenochtitlan. Some wooden post samples were selected for accelerator mass spectrometry radiocarbon (AMS 14C) dating, believed to have been used as chinampa supports. We seek to determine their temporality and possible reuse by Hispanic builders. The second one, the La Otra Banda Site, is part of the human settlements that were founded around Cuicuilco, one of the main ancient urban centers of the highlands of Central Mexico. Some human bones and coal samples were selected to be dated, aiming to establish the site’s occupation time.

In paleoenvironmental research, several proxies are used to reconstruct climate and vegetation. The establishment of a chronological framework allows for the association of different proxies and correlation of events happening in different geographic areas. Cultural deposits, such as the shellmounds found along the coast of Brazil, play an important role in paleoenvironmental interpretations. Here, we have employed anthracological analysis in charcoal fragments from the Amourins shellmound, located at the margins of the Guanabara Bay, Rio de Janeiro. This allowed for the taxonomic identification and selection of short-lived trees and specific parts of plants for accurate radiocarbon dating. We recorded genera and families typical of the Atlantic Forest, restinga forest, open restinga and mangrove. The 14C ages of charred nuts from different occupational layers range from 3807 ± 35 to 3503 ± 70 BP and a sequential chronological model was built, relating the predominance of mangrove vegetation to the period between 4130–3960 cal BP.

When European colonists arrived in the late 19th century, large villages dotted the coastline of the Gulf of Papua (southern Papua New Guinea). These central places sustained long-distance exchange and decade-spanning ceremonial cycles. Besides ethnohistoric records, little is known of the villages’ antiquity, spatiality, or development. Here we combine oral traditional and 14C chronological evidence to investigate the spatial history of two ancestral village sites in Orokolo Bay: Popo and Mirimua Mapoe. A Bayesian model composed of 35 14C assays from seven excavations, alongside the oral traditional accounts, demonstrates that people lived at Popo from 765–575 cal BP until 220–40 cal BP, at which time they moved southwards to Mirimua Mapoe. The village of Popo spanned ca. 34 ha and was composed of various estates, each occupied by a different tribe. Through time, the inhabitants of Popo transformed (e.g., expanded, contracted, and shifted) the village to manage social and ceremonial priorities, long-distance exchange opportunities and changing marine environments. Ours is a crucial case study of how oral traditional ways of understanding the past interrelate with the information generated by Bayesian 14C analyses. We conclude by reflecting on the limitations, strengths, and uncertainties inherent to these forms of chronological knowledge.

This study obtained calendar dates by radiocarbon accelerator mass spectrometry (14C AMS) dating sequential tree-rings of wooden support posts from the buried remains of traditional Kitkahahki Pawnee earthlodges preserved at an archaeological site on the Central Great Plains, USA. The tree-ring segments from the site were dendrochronologically analyzed prior to this study, but the cross-matched site chronology could not be definitively cross-dated and was thus “floating” in time. Our study represents the first floating tree-ring chronology from the Great Plains to be anchored in time by means of independent radiocarbon analysis. Three specimens were analyzed and dated to 1724–1774 CE (82.0% probability), 1774–1794 CE (95.4% probability), and 1800–1820 CE (95.4% probability). These dates correspond to the hypothetical timing of Kitkahahki ethnogensis, the main phase of village growth in the area, and a later reoccupation during a turbulent period in regional history. The results of this study conform to a scenario in which chaotic social conditions correspond to an increase in residential mobility between the core of Pawnee territory and a southern frontier in the Republican River valley.

The main goal of our research project was to date the Early and Middle Copper Age (4500/4450–3800 cal BC) of the Great Hungarian Plain more precisely. In our project, we took samples for accelerator mass spectrometry (AMS) dating from both settlement features and burials, and the data were analyzed using Bayesian modeling. We examined the Early and Middle Copper Age finds of the Great Hungarian Plain on several levels (site, microregional, and regional levels) using a bottom-up approach. The AMS measurements were supplemented by statistics-based pottery analysis in order to make our understanding of the relationship between the Tiszapolgár and Bodrogkeresztúr cultures more detailed. As a result, we can see a significant, 130 (68.2%) 230 years overlap between the two types of find assemblages, which contradicts to the earlier accepted chronological sequences created by the traditional culture-historical approach. According to the stylistic analyzes, the two ceramic styles are not clearly distinguishable.

The excavation of a building in the village of Felanitx in the eastern part of the island of Mallorca (Balearic Islands) has revealed the existence of a small necropolis. The inhumations did not provide grave goods except for a bronze belt buckle for which the typological study suggests a Late Antique chronology. The stratigraphical sequence however seems to suggest a possible evolution of the space across time since some graves are cut by others. In order to obtain an absolute date for the necropolis and to verify if there are chronological differences between the graves, a total of 6 human bones samples have been 14C dated by AMS. The results of the radiocarbon dating confirm a Late Antique chronology (4th to 7th century AD) for the graves but do not suggest a chronological evolution. Despite the fact that the knowledge of the necropolis is still fragmentary, the results are extremely important because they provide an absolute date for a Late Antique necropolis in the Mallorcan rural area.

Over the past few decades, several excavations that have been performed in the Fars Neolithic sites have resulted in the presentation of different chronologies for the region. Most of the research in Fars centered on the Kur River Basin (KRB). Fars has always had a different environment for the formation of different cultures over time, therefore, in order to reach a better understanding of the prehistoric cultures of the region it is necessary to make a brief review of the geographical zones of the plains and valleys of Fars province. Taking into account the existence of several questions and ambiguities regarding Neolithic Fars, the Hormangan site, located in the Bavant River Basin, was excavated. During the excavation, two settlement phases were identified that contained cultural materials relatively comparable to Tol-e Mushki, Tol-e Jari B, Kushk Hezar, and Rahmat Abad sequences. The goal of this paper is to explore the absolute chronology of the Hormangan site as well as other Neolithic sites located in the northern half of the Fars region with a special reference to the local cultural and technological sides of different Neolithic sites throughout the region. Bearing in mind the similarities of Bashi materials with Hormangan, Rahmat Abad, and Mushki regions and the absolute chronology of these regions, consideration of Bashi phase does not seem logical. Therefore, by comparing the cultural materials and absolute chronology done in other regions, a sequence chronology including Rahmat Abad (7500–7000 BC), formative Mushki (7000–6400 BC), Mushki (6400–6000 BC), Jari (6000–5600 BC), and Shams Abad (5600–5200 BC) for the Neolithic period of Fars can be presented. According to the excavation of Rahmatabad and Tal-e Sangi, it seems that Fars was inhabited in the middle of the 8th millennium BC and the Neolithic package entered this area, and there is no evidence of the Neolithization process. In the past, the Mushaki period was introduced as the oldest pottery Neolithic period, but with new excavations, it seems that the use of pottery had become common in Fars, as in many parts of Southwest Asia, around 7000 BC.

Collagen extraction depends on the state of bone preservation, and the acidity of Brazilian soils often prevents the use of this material for radiocarbon dating. When available, however, bone samples constitute very important chronological records for both archaeological sites and natural depositional sites of specific animals. The extraction of collagen was performed using two filters, the first aiming to remove insoluble contaminants, and the second, a vivaspin ultrafilter 30KD to retain large molecular weight materials. The collagen was liofilized and converted to CO2 by combustion in sealed quartz tubes with CuO and Ag. The graphite was produced by zinc reduction in independently sealed Pyrex™ tubes. In order to verify the accuracy of this protocol, we analyzed a modern bone and four previously dated fragments, including those from the Sixth International Radiocarbon Intercomparison (SIRI), and a fragment of human bone from the Amourins site, a Brazilian shellmound. The results for the known age material are in agreement with the expected and the studied sector of Amourins shellmound was dated 4100–3900 years cal BP from a chronological model performed with charcoal dating found in different stratigraphic layers. Samples were dated at the radiocarbon laboratory of Universidade Federal Fluminense (LAC-UFF) in Brazil.

Teotihuacan is one of the most studied archaeological sites in Mesoamerica because of its exceptional size and urban planning; however, its last years of occupation and abandonment are still under debate. We report a high-resolution chronology for the Xalla complex integrating archaeomagnetic dates, radiocarbon (14C) ages, and detailed archaeological information about sample type and context in a Bayesian model. The model includes 42 14C ages and 7 archaeomagnetic dates grouped in 6 phases, including samples from collapsed roofs with 14C ages earlier than expected, suggesting a problem of inbuilt age. The archaeomagnetic dates on lime plasters were classified in unburned samples, related to the time of construction, and burned samples, related to the Big Fire associated to the abandonment of Teotihuacan. The modeled 14C ages resulted in shorter intervals, with the possibility of differentiating the construction phases, confirming that big beams had inbuilt age. Further, combining the two dating methods and classifying lime plaster samples in burned and unburned, it was possible to date different events within the same archaeological context. It is concluded that by combining these two dating methods and understanding the moment that each sample is dating, it is possible to obtain solid and precise chronologies.

Recent radiocarbon (14C) research demonstrates that the urban culture of Early-Bronze III in the southern Levant ends around 2500 BC, and not around 2300 BC as was widely assumed. This should extend the Intermediate Bronze Age by 200 years. Charred olive pits from Intermediate Bronze Age contexts in the site of Khirbat el-‘Alya Northeast in the Judean Shephelah region (Israel) were 14C dated, resulting in calibrated dates around 2500 BC. The date range of Khirbat el-‘Alya Northeast samples is an indication that in the Mediterranean parts of the southern Levant, the Intermediate Bronze Age material culture appeared around the time of the decline of the preceding culture of Early-Bronze III—around 2500 BC or somewhat earlier. Possible Intermediate Bronze settlement pattern and the site’s relation to the nearby Early-Bronze city of Tel Yarmuth are discussed based on previous Intermediate Bronze and Early-Bronze related research in the surrounding area.

The article presents the results of the absolute dating of 31 pre-Columbian funerary bundles excavated on the Cerro Colorado site located in the northern part of the Peruvian Central Coast, where the Chancay culture developed in the last centuries before the Spanish invasion. The typical custom in this region was to wrap the dead with textiles and a vegetal material, by which the bundle was created. The funerary bundles of the Cerro Colorado differed in terms of the complexity, quantity and quality of the materials used (especially textiles and metal ornament). Before our project, there was not a single radiocarbon (14C) date for an undisturbed Chancay tomb, which made it impossible to understand the temporal dependency between the elaborated, standard, and modest bundles. Our results finally shed light on their proper chronological position, also demonstrating that the most elaborate bundles were created between the 13th and 15th centuries.

Population density is an important variable in the development of social complexity. Estimating population densities from the archaeological record requires combining estimates of population, area, and time. Archaeological population estimates tend to be reported as a maximum population derived from the total accumulation of discrete archaeological material types, usually ceramics or radiocarbon (14C) dates. However, given the palimpsest nature of the archaeological record at recurrently occupied archaeological sites, these maximal, total estimates are, at best, a poor reflection of contemporaneous populations. I present a method for calculating average yearly population densities for occupations at a large, multicomponent site using a combination of distributional data and 60 14C dates. By employing this method at other sites in the same region, modeling intra-regional population dynamics at fine time scales will be possible.

The San Pedro de Atacama oases, located in northern Chile’s hyperarid Atacama Desert, have been occupied for at least 3000 years. Here, we examine cemetery use in the oases, with emphasis on the Middle Period (ca. AD 400–1000). By modeling of a large corpus (n=243) of radiocarbon dates, over 90% of which are direct AMS assays of human bone collagen, we attempt to establish a temporal framework by which to explore the establishment of formalized social inequality in this period. Modeling of these dates at three locally defined scales (all ayllus, inter-ayllu, and intra-ayllu) permit heretofore unavailable insights into the chronological and spatial dimensions of life and mortuary activity in the oases and allow us to better contextualize patterns of social inequality during the dynamic Middle Period. The results of this modeling indicate two distinct peaks of occupation during the Middle Period in San Pedro and document significant temporal variability in cemetery use patterns on both inter- and intra-ayllu scales. These results stress the importance of local social and environmental factors to the occupation of the oases and provide crucial chronological structure for future archaeological and bioarchaeological research in the region.

Eurasian steppes experienced frequent cultural transfers, human migration, and diffusion of techniques during the Bronze Age. The Hami Oasis is one of the most dynamic areas and has attracted multiple cultural flows. It is an important area that connects various routes of the Tianshan Corridor with the Hexi Corridor in western China. The Tianshanbeilu cemetery is the largest Bronze Age cemetery in Hami. Thirty-seven new radiocarbon dates allowed us to establish a new and more accurate chronology for Tianshanbeilu. Our results showed that the Tianshanbeilu cemetery was used from approximately 2022–1802 cal BC and remained in use from 1093–707 cal BC. This indicates that Tianshanbeilu is the earliest and longest-used known cemetery in eastern Xinjiang. By incorporating the typology of artifacts and stratigraphic relationships, the development of the Tianshanbeilu cemetery was divided into four phases. The first phase was from 2011–1672 cal BC, the second phase was from 1660–1408 cal BC, the third phase was from 1385–1256 cal BC, and the fourth phase was from 1214–1029 cal BC.

The Mayan Codex of Mexico (MCM), the only Mayan codex found in the 20th century, was unveiled in 1971 during the Ancient Maya Calligraphy exhibition at Club Grolier. The codex comprises 10 pages of bark paper in accordion format, coated with a layer of plaster on both sides. It illustrates the synodic cycles of Venus, with its four phases. Since its discovery, the MCM has been subject to controversy and discussions about its authenticity. In 2016, a group of specialists led by Baltazar Brito chief of the National Library of Anthropology and History, carried out an exhaustive study of the codex with the purpose of determining its temporality and authenticity. In this work, the pre-Columbian authenticity of the codex is verified by the radiocarbon (14C) technique using AMS. Two cleaning procedures were contrasted: the standard acid-base-acid (ABA) protocol and a second one with Soxhlet plus ABA. Results obtained when samples were prepared following ABA protocol only, placed the age of the bark paper between 991 and 1147 cal AD. The second cleaning method with Soxhlet plus ABA, resulted in younger ages, between 1159 and 1261 cal AD. However, we consider that when Sohxlet is used as part of the cleaning protocol, organic contaminants are reduced to a minimum, and 14C dates are more reliable. These results indicate that the vegetal support of the MCM belongs to Postclassical Mayan period and place it as the oldest known manuscript of America found to date.

Radiocarbon (14C) has been instrumental in clarifying how people came to inhabit the expanse of Pacific Oceania, now supporting an “incremental growth model” that shows a number of long-distance sea-crossing migrations over the last few millennia. A crucial step in this narrative involved the initial settlement of the remote-distance Oceanic region, in the case of the Mariana Islands around 1500 BC. The Marianas case can be demonstrated through delineation of stratigraphic layers, dating of individual points or features within those layers, redundant dating of samples in secure contexts, localized and taxon-specific corrections for marine samples, and cross-constraining dating of superimposed layer sequences. Based on the technical and methodological lessons from the Marianas example, the further steps of the incremental growth model will continue to be refined across Pacific Oceania. Many of these issues may be relevant for broader research of ancient settlement horizons in other regions.

At the close of the Bronze Age, a tendency developed in Central Europe towards the concentration of settlement and fortification of sites which served special economic and social functions. One of the largest centers of this kind in the northern part of Central Europe is the Łubowice stronghold (SW Poland). Archaeological excavations allowed the stratigraphy of the fortification remnants to be comprehensively investigated. In their final stage, these fortifications comprised of a monumental earthen rampart with timber structures, which were later destroyed in a violent fire. Originally, the destruction of the Łubowice stronghold was linked with the raids by nomadic Scythians and dated to the first half of the 6th century BC. However, radiocarbon analyses of charcoal from the burned rampart relics have shown that the destruction of the fortifications took place in the 9th century BC. The new dating of the moment when the Łubowice fortifications was burned down, i.e. “shortly after 845–802 cal BC” places this event within historical processes which reshaped the cultural picture in much of Central Europe at the dawn of the Iron Age. The spreading of a new, Hallstatt cultural model was associated with deep changes in social structures.

According to the classical chronology of the Inca State, the ascension to power of Pachacuti Inca took place around AD 1438 and the construction of Machu Picchu began by AD 1450–1460. However, the improvement in the accuracy of radiocarbon (14C) dating resulting from the application of Bayesian analysis has changed our view of the historical chronology. This new research raises questions about our understanding of the cultural development of the Machu Picchu area, in the light of the new proposed chronological scheme. This paper presents a set of 11 new14C dates, derived from AMS, from the sites of Llaqta of Machu Picchu, Chachabamba, and Choqesuysuy. The latter two sites are situated within the Machu Picchu National Archaeological Park (Arqueología del Santuario Histórico Nacional y Sitio Patrimonio Mundial de Machu Picchu) and have been interpreted as being part of the contemporary Late Horizon Inca landscape. The new14C ages are modeled using Bayesian inference and present a revised dating framework for these sites and their chronological relationship with Llaqta of Machu Picchu.

A zolnik excavated in 2016–2018 at the hillfort identified as the Scythian cultural circle in Chotyniec (southeastern Poland, 8 km west of the current Poland–Ukraine border) provided a very large quantity of archaeological sources and organic materials. From the latter, 17 samples coming from different horizons were selected for dating and were used to build a chronological model of functioning of the zolnik. Absolute dating is particularly important because the discovered artifacts (especially the most common handmade ceramics) do not show large chronological diversity. The use of the zolnik was estimated at 250–300 years, i.e. between 7th/6th and 4th/3rd century BC. Stratigraphic observations and good references of absolute chronology based on artifacts, including imported Greek ceramics, first in this part of Central Europe, proved to be significant. Older radiocarbon dates correspond to typological dating of Greek amphoras (7th/6th–6th century BC).

Excavations of the remains of the medieval church of Santa Maria di Campogrosso (Sicily) were conducted by the Institute of Archaeology and Ethnology of the Polish Academy of Sciences as part of scientific cooperation with Soprintendenza per i Beni Culturali ed Ambientali di Palermo. Based on the records of post-medieval historians, the construction of the church was placed in the second half of the 11th century, which contradicts the findings of architectural historians, who dated the building to the 13th-century and even later. As a result of archaeological excavations carried out in 2015–2018, it was possible to locate unknown fragments of the church’s structure and the remains of the cemetery adjacent to it. The 14C dating carried out for samples obtained from the walls of the existing building as well as from bone remains from the churchyard in combination with stratigraphic information from archaeological trenches and the chronology of coins indicates a high probability of the church construction in the second half of the 12th century and confirms the end of the monastery complex existence at the end of the 13th century.

Recent archaeological excavations on Rakahanga Atoll, Northern Cook Islands, produced one of the earliest examples of dog (Canis familiaris) remains found on East Polynesian atolls. Direct dating of these and other Pacific Island fauna by AMS is complicated by a number of factors. (1) The animals’ diets may consist of marine and terrestrial protein. (2) Marine 14C is itself a mix of carbon pools with localized offsets that vary over time and space. (3) The region is potentially impacted by inter-hemispheric mixing of atmospheric 14C. Stable isotope analysis of gelatin extracted from dog teeth was used to estimate marine/terrestrial dietary components and paired terrestrial and marine samples were used to constrain local atmospheric and marine carbon offsets. The dates were modeled as a phase in a Bayesian chronological framework using mixed calibration curves. The resulting models confirm the presence of dogs on Rakahanga shortly after the initial colonization of the region and suggest that dogs were among the species that accompanied voyagers as they discovered and settled new islands. These methods can be applied to accurately date any marine-influenced terrestrial vertebrate remains in Remote Oceania.

We combine the results of a radiocarbon (14C) dating program with archaeogenetic, osteological and sparse stratigraphic data, to construct a Bayesian chronological model for a multi-generational sequence situated entirely on a plateau in the 14C calibration curve. Calibrated dates of individual human bones from the Late Neolithic gallery grave at Niedertiefenbach, Hesse, Germany, span the entire calibration plateau in the late 4th millennium (ca. 3350–3100/3000 cal BC), but our model restricts the overall period of burial to 3–6 generations centered on the later 3200s, and provides narrower absolute date ranges for specific individuals and associated events. We confirm the accuracy and robustness of this model by sensitivity tests of each of its components. Beyond providing a more dynamic narrative for the formation of the heterogenous burial population at Niedertiefenbach, our results show that calibration plateaus are suitable periods for Bayesian chronological modeling of even relatively brief sequences, provided that all the information employed is correct. Prior information constraining both the order of events, and of potential date differences between them, is essential for the model to give accurate, unimodal estimates of the dates of these events.

The results of a short program of landscape, buildings and materials analysis undertaken at Achanduin Castle, Lismore, Scotland (NM 8043 3927) are presented from the pilot phase of the Scottish Medieval Castles & Chapels C14 Project (SMCCCP). The study presents the first independent chronological evidence relating to the construction of this important medieval building, by radiocarbon analysis of a limited assemblage of Mortar-Entrapped Relict Limekiln Fuel (MERLF) fragments. Informed by a wider investigation of structural phasing and sample taphonomy, these measurements are constrained within a series of different Bayesian models, to generate a range of comparative estimates for the building’s constructional chronology. The precision with which the construction of this building can now be dated, from other evidence associated with the site, makes the Achanduin Castle study a useful point of reference for wider materials research.

Bayesian analysis of radiocarbon (14C) dates in North American archaeology is increasing, especially among archaeologists working in deeper time. However, historical archaeologists have been slow to embrace these new techniques, and there have been only a few examples of the incorporation of calendar dates as informative priors in Bayesian models in such work in the United States. To illustrate the value of Bayesian approaches to sites with both substantial earlier Native American occupations as well as a historic era European presence, we present the results of our Bayesian analysis of 14C dates from the earlier Guale village and the Mission period contexts from the Sapelo Shell Ring Complex (9MC23) in southern Georgia. Jefferies and Moore have explored the Spanish Mission period deposits at this site to better understand the Native American interactions with the Spanish during the 16th and 17th centuries along the Georgia Coast. Given the results of our Bayesian modeling, we can say with some degree of confidence that the deposits thus far excavated and sampled contain important information dating to the 17th-century mission on Sapelo Island. In addition, our modeling of new dates suggests the range of the pre-Mission era Guale village. Based on these new dates, we can now say with some degree of certainty which of the deposits sampled likely contain information that dates to one of the critical periods of Mission period research, the AD 1660–1684 period that ushered in the close of mission efforts on the Georgia Coast.

More than 70 logboats are known in Lithuania and about half of them date before 1800 cal AD. This paper reviews these more ancient logboats, which were discovered in the beds of former or still existing lakes and rivers and present new radiocarbon (14C) dates and wood taxa identifications. Special attention is paid to the logboat found at Šventoji 58, which is at present the oldest 14C-dated (2895–2640 cal BC) logboat found East of the Baltic Sea. Most logboats from the pre-1800s period were 14C dated to medieval and early modern periods and they were made out of pine and oak wood. From a very scarce dataset available it seems that oak wood was introduced into logboat building by Neolithic people, who also brought new technologies in stone tool production. We also noted that 14C dating does not confirm the logboat typology suggested in earlier studies.

Given the nature of medieval artifacts and resulting research requirements, a precise temporal classification is essential. It is especially important for the purposes of medieval archaeology in interpreting archaeological finds/finding situations and identifying them with a historical events or figures, for example, to identify skeletal remains of a known historical figure or to establish a chronological sequence of various cultural and architectural changes within an area. Due to the fact that the uncertainties of radiocarbon (14C) analyses have been decreasing in recent years, the applicability of 14C dating for such purposes is now growing. In this work, we aim to demonstrate the current possibilities of the use of AMS 14C analyses on specific cases and confront the results with other available data. 14C data from skeletal remains of members of the oldest Czech ruling dynasty of the Přemyslids (about 880–1306 AD) were obtained in recent years. Archaeological research conducted in the three oldest churches in the Prague Castle discovered skeletal remains of three members of the second, two members of the fourth and two members of the fifth generation. This case study of the application of 14C data has three parts: i) identification of excavated individuals; ii) demonstration of the application using current AMS-based analysis of 14C on medieval osteological material and tests of our preparation method; iii) contributing to discussion and consulting with other problematical 14C age alteration influenced by diet, age of bone collagen or seasonal variation of 14C activity. The obtained results and the issues arising from them clearly highlight the necessity of a multidisciplinary cooperation in this type of study.

The formation of commingled human bone assemblages is a key aspect for better understanding funerary rituals. The megalithic cemetery of Panoría (Spain) provides an excellent opportunity to explore bone assemblage formation thanks to the recent excavation of an undisturbed burial. For this purpose, we have approached the differential skeletal representation found between bone and teeth at the site through radiocarbon (14C) dating and Bayesian modeling. The comparison between the series of 14C dates on bone (n=12) and teeth (n=14) stress three main aspects: (1) the dates of teeth show a long period of funerary use before the deposition of the human bone remains; (2) both kinds of samples appear to be chronologically sequenced; the end of the teeth 14C series matches with the beginning of human bone deposition; and (3) bone remains span a short period, not more than a few decades, which probably represents the last episode of intense mortuary activity. These differences suggest that teeth could be the evidence of skeletal depositions subsequently removed from the tomb. The deposition and removal of bone remains emerge as key aspects in the formation of the bone assemblage.

The Royal Institute for Cultural Heritage (RICH) radiocarbon (14C) laboratory in Brussels, Belgium, has acquired experience for pretreating samples with 60 years of involvement in 14C dating, and the implementation of routine protocols. These procedures as applied to wood, seeds, charred materials, bones, ivory, textiles (silk, wool, cotton, linen), paper, shells, cremated bones, mortars, lead carbonates, sediments, etc. are described in detail in this paper. They are evaluated against reference materials.

Stone and earthen architecture is nearly ubiquitous in the archaeological record of Pacific islands. The construction of this architecture is tied to a range of socio-political processes, and the temporal patterning of these features is useful for understanding the rate at which populations grew, innovation occurred, and social inequality emerged. Unfortunately, this temporal patterning is poorly understood for many areas of the region, including the Sāmoan archipelago. Here, we describe a project directed toward establishing a robust chronology for the construction of these earthen and stone terraces and linear mounds on Ta‘ū Island. Using recent methodological improvements, we highlight the tempo at which different architectural types were constructed on the island and the implications for understanding demographic expansion and changing land tenure practices in the last 1500 years. This research suggests the construction of architecture was largely confined to the 2nd millennium AD with a small number of terraces plausibly built in the 1st millennium AD. This temporal patterning suggests that a reconfiguration of settlement patterns occurred within West Polynesia as people there moved into other regions of Oceania.

Reversals and plateaus in the radiocarbon (14C) calibration curve lead to similar 14C ages applying to a wide range of calendar dates, creating imprecision, ambiguity, and challenges for archaeological dating. Even with Bayesian chronological modeling, such periods remain a problem when no known order—e.g., a stratigraphic sequence—exists, and especially if site durations are relatively short. Using the reversal/plateau AD 1480–1630 and the archaeology of northeastern North America as our example, we consider possible strategies to improve chronological resolution across such reversal/plateau periods in the absence of stratigraphic sequences, including uses of wood-charcoal TPQs from even very short wiggle-matches, and site phase duration constraints based on ethnohistoric and archaeological evidence.

With the popularization of carbon and nitrogen stable-isotope analysis methods used on archaeological samples from Xinjiang, the ancient paleodiet there has been revealed. However, research about isotopic analysis combined with environmental factors is rare, especially in such a variable and complex climate as that of the Tianshan region. We systematically analyzed the δ13C and δ15N results from animals and humans for dietary reconstruction of nomadic pastoralists from the Tianshan region during 3900–1200 cal BP. The δ13C and δ15N values for animals (sheep/goat, horse and cattle; n = 57) have a wide range from –20.8‰ to –14.7‰ for δ13C (–19.2 ± 1.0‰) and 3.2‰ to 9.9‰ for δ15N (7.0 ± 1.2‰). The δ13C and δ15N values from humans range from –19.6 to –12.3‰ (–16.0 ± 1.5‰) and 7.1 to 16.7‰ (–13.6 ± 1.5‰), respectively. The animal δ15N results indicate that the dry environment in the Tianshan region may result in elevated δ15N values. Synthesizing animal and human isotope results suggests that the inhabitants engaged in mobile herding economies subsidized with crops and wild animal meat from the Tianshan Mountains. In conclusion, we found that the regional environment closely relates to crop types, and temporal climate change has an effect on human dietary structure. Therefore, climate condition cannot be ignored when studying human paleodiet.

Here we present direct dates of food grains and insights into agricultural strategies adopted by Harappans from a newly excavated Indus site 4MSR (Binjor) in northwestern India. The site revealed Early and Mature Harappan phases delimited by a Transitional phase based on ceramics and archaeological artifacts. The macro-botanical remains revealed that the site was occupied by an agricultural society during the Early phase (~2900−2600 BCE), whereas diversification of the economy including more craft specialization, along with an agricultural advancement was witnessed during the Mature phase (~2500−1800 BCE). The advent of summer crops during the Transitional phase (~2600−2500 BCE) indicates climate amelioration attributed to inception of strong Indian Summer Monsoon (ISM). By the end of Mature phase, millet was recorded due to a change in climatic (relatively lower moisture) conditions or drying of the river channel, which forced the settlers to shift the cropping (agricultural) strategy in the region. Plausibly, this unavailability of water during the end of Mature phase led the settlers to abandon the site in order to migrate somewhere else. The subsistence pattern indicates continuity and change in temporal domain likely owing to changing climatic/environmental conditions, resources and knowledge gained by exchange/trade of cultures over a time period between ~2900 BCE to 1800 BCE.

There are few papers that focus on optically stimulated luminescence (OSL) dating of earthen mortars. These mortars are abundant in historical buildings in northwestern Spain. The Basílica da AscensiónyForno da Santa building is an unfinished church built on a previous structure that was transformed into a crypt (Allariz, Ourense, NW Spain). Previous archaeological studies established a sequence of phases of construction, the first dating back to the Iron Age, with significant changes occurring in the Early and Late Medieval ages. The only datable material in the crypt is earthen mortar. Thus, eight mortar samples (seven joint mortars and one wall infill) were taken, seven of them dated by OSL. The dose rate was assessed, and the expected equivalent doses estimated based on the established archaeological age. Several grain sizes (from fine to coarse) were used in small multigrain aliquots to assess the equivalent doses and ages. No evidence of partial bleaching was observed in most samples and grain sizes. The resulting ages are younger than expected for most samples. This is explained by the fact that joints were repaired with new mortar from the 16th century onwards.

The monastery of St. John in Müstair, a UNESCO world heritage site, preserves archaeological remains and stone structures dated from the 8th century to the present. It has been extensively studied archaeologically so that numerous samples of historical materials, including mortar, are available for study. In addition to that, some of the structures have been precisely dated with dendrochronology. The monastery is located in a region characterized by dolomite rocks and the mortars are therefore of dolomitic nature, being perfectly suited to test the possibility of being dated with 14C. Furthermore, the presence of embedded carbon fragments has provided additional independent data to support or deny the results of mortar dating. A comparison of the results obtained from radiocarbon (14C) dating of bulk mortars, sieved fractions enriched in binder, lime lumps and carbon fragments, for two samples is presented, in relation to the petrographic characterization and the mineralogical phase content. This preliminary study shows that the dating of 14C can potentially be applied to the mortar of Müstair, as results in accordance with the established chronologies have been obtained for one sample. However, if the dolomitic sand contamination is very high, further studies are needed to develop a specific sample preparation technique.

Faunal assemblages from the pre-Contact period sites Frisby-Butler and Hornblower II on Marthaʼs Vineyard, Massachusetts, USA, remain unstudied since excavation during the 1980s. This project establishes radiocarbon (14C) dates from faunal remains and evaluates occupation and abandonment at each site. 14C measurements were collected from 17 specimens and 13 dates from previous analyses were re-examined. Dates were identified from the archaeological time periods Transitional Archaic (2700–3700 BP), Early Woodland (2000–2700 BP), and Late Woodland (450–1200 BP) at Frisby-Butler. Occupation likely represented seasonal visitations during autumn and winter to hunt based on white-tailed deer (Odocoileus virginianus) demographic profiles. A combined dataset of new and re-calibrated 14C measurements from Hornblower II date to the Late Archaic (3700–6000 BP), Early Woodland, Middle Woodland (1200–2000 BP), and Late Woodland periods. Settlement was focused on gathering warm-weather foods like demersal fish and lakebirds. Together, the sites demonstrate periodic seasonal use of the southwest coast of the island throughout the Late Holocene and fit within an established regional pattern in southern New England.

Radiocarbon (14C) dating was performed on samples from the prehistoric settlement at Makriyalos, northern Greece, a “flat extended” (rather than tell) site. Two separate occupation phases, Makriyalos I and II, were clearly distinguished on different sides of a low hill and belonged to the Late Neolithic I and II periods, respectively. Individual phases related to the use of circuit ditches and borrow pits were also recognized and dated. Phase modeling was applied in order to establish the sequence and duration of use of different features. The earliest activity seems to be around 5450 BC, among the earliest dates in northern Greece for the beginning of the LN and perhaps reflecting some earlier activity. The transition from LNI to LNII occurred at around 4950 BC without discontinuity earlier than other sites in Macedonia but perhaps same time as Thessaly. Intermediate ditch cutting phases occurred at 5300 and 5050 BC. A cemetery in the area of the settlement, initially thought to relate to the LNII phase of the settlement, was shown to date in the EBA period (beginning of 3rd millennium BC).

The Centre for Isotope Research (CIO) at the University of Groningen has operated a radiocarbon (14C) dating laboratory for almost 70 years. In 2017, the CIO received a major upgrade, which involved the relocation of the laboratory to new purpose-built premises, and the installation of a MICADAS accelerator mass spectrometer. This period of transition provides an opportunity to update the laboratory’s routine procedures. This article addresses all of the processes and quality checks the CIO has in place for registering, tracking and pretreating samples for radiocarbon dating. Complementary updates relating to radioisotope measurement and uncertainty propagation will be provided in other forthcoming publications. Here, the intention is to relay all the practical information regarding the chemical preparation of samples, and to provide a concise explanation as to why each step is deemed necessary.

The emergence of hilltop settlements presents a pattern of the first enclosed sites that reflect economic development in several regions within the Southeastern Baltic Bronze Age. This novelty reflects increasing social complexity, differentiating economic relations, as well as rising tension in the region. The phenomenon has received a great deal of interpretation, but chronological problems still remain understudied. Researchers tend to seek the start of hilltop settling practice from early to late II millennium BC. This paper presents14C dates from 7 sites in inland Lithuania, where hitherto no absolute dates were published. The majority of absolute dates has been calibrated to the Hallstatt radiocarbon calibration plateau (ca. 800–400 cal BC) which is significantly later than previously presumed based on dates from Belarusian sites. However, several dates from previously dated hilltop settlements in the region predate the effect. These results indicate the start of hilltop settling practice around 11th–9th centuries cal BC. Review of new and previously published radiocarbon dates suggests a different internal development between SE Baltic coastal and inland regions, likely locating zones, where economic outside stimulus preconditioning emergence of hilltop settlements occurred earlier.

Historical sources reveals that Copenhagen was founded in the late 12th century AD by Bishop Absalon. However, during the excavation for the new metro in central Copenhagen a previously unknown early medieval cemetery was discovered and excavated at the Town Hall Square. Radiocarbon (14C) analysis was conducted on the 9 individuals found in situ, together with 11 individuals from the other early medieval cemetery in Copenhagen, belonging to the St Clemens church. The radiocarbon analysis places the onset of the cemeteries to the early 11th century AD and therefore questions the age of Copenhagen and hence the archaeological and historical perception of the Danish historical record. Here a detailed account of the radiocarbon-based Bayesian model is presented.