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Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: During the Middle Ages, Portugal witnessed unprecedented socioeconomic and religious changes under transitioning religious political rule. The implications of changing ruling powers for urban food systems and individual diets in medieval Portugal is poorly understood. This study aimed to elucidate the dietary impact of the Islamic and Christian conquests. Materials and Methods: Radiocarbon dating, peptide mass fingerprinting (ZooMS) and stable isotope analysis (δ13C, δ15N) of animal (n = 59) and human skeletal remains (n = 205) from Muslim and Christian burials were used to characterize the diet of a large historical sample from Portugal. A Bayesian stable isotope mixing model (BSIMM) was used to estimate the contribution of marine protein to human diet. Results: Early medieval (8–12th century), preconquest urban Muslim populations had mean (±1SD) values of −18.8 ± 0.4 ‰ for δ13C 10.4 ± 1 ‰ for δ15N, indicating a predominantly terrestrial diet, while late medieval (12–14th century) postconquest Muslim and Christian populations showed a greater reliance on marine resources with mean (±1SD) values of −17.9 ± 1.3‰ for δ13C and 11.1 ± 1.1‰ for δ15N. BSIMM estimation supported a significant increase in the contribution of marine resources to human diet. Discussion: The results provide the first biomolecular evidence for a dietary revolution that is not evidenced in contemporaneous historical accounts. We find that society transitioned from a largely agro‐pastoral economy under Islamic rule to one characterized by a new focus on marine resources under later Christian rule. This economic change led to the naissance of the marine economy that went on to characterize the early‐modern period in Portugal and its global expansion. [ABSTRACT FROM AUTHOR]

Since a radiocarbon chronology of the Dalton culture in the Southeast was first proposed, several new sites have been dated. I propose a new chronology based on radiocarbon dates from sites in the Dalton Heartland and its eastern periphery using Bayesian statistical models in OxCal and an analysis of the associated diagnostic projectile points. The analyses indicate that the Dalton culture probably evolved from the Clovis or Gainey phenomena about 12,680 cal BP (ca. 10,700 BP) and lasted at least until ca. 10,400 cal BP (ca. 9,200 BP), if not several centuries later. I propose early and late Dalton phases that follow changes in how Dalton points were made and resharpened. It appears that the people living to the east of the Heartland followed a different trajectory of projectile point evolution. There, notched points appear about 11,500 cal BP, while in the Heartland, true notched points do not appear in large numbers until the Graham Cave point over 2,000 years later. The chronologies demonstrate that early, coeval, region-wide cultural changes may not have been the norm. They also raise interesting questions about how people in the Heartland and its eastern periphery interacted. [ABSTRACT FROM AUTHOR]

Eggs from an intestinal parasite has been found in a burial radiocarbon dated to 5210-4840 cal BC in Motala, east-central Sweden. The two helminth eggs are identified as Trichuris trichiura (human whipworm). Control samples from the cemetery site were all negative and confirmed that there was no evident contamination of younger material. This discovery raises new questions concerning the early geographical spread and timing of parasitic diseases among hunter-gatherer societies in northern Europe, and in the temperate zone of the northern hemisphere. Whipworm infection (Trichuriasis) is perhaps the disease most associated with crowding and poor sanitation, and as it manifests itself in the youngest dated burial, it could be a contributing factor to the final abandonment of the Mesolithic settlement. Also, parasite eggs found in a soil sample from the Neolithic Alvastra pile dwelling could indicate the continued presence of the Trichuris parasite in east-central Sweden. Generally, parasite ecology can aid in reconstructing human behaviors that include aspects of sedentism, mobility, food preferences, hygiene and other social practices. [ABSTRACT FROM AUTHOR]

This study carried out accelerator mass spectrometry radiocarbon (AMS 14C) measurement of Japanese tree rings dating from the middle to early modern eras to investigate calibration curve fine structure. Tree-ring ages were determined by dendrochronology or δ18O chronology for Japanese trees. 14C ages from the 15th century to the middle of the 17th century followed the IntCal13 calibration curve within measurement error. Different patterns of fluctuations during the latter half of the 17th century to the early the 18th century were observed in different tree samples. In the 19th century, patterns of 14C ages of different samples appeared similar but did not exactly match each other. [ABSTRACT FROM AUTHOR]

We obtained radiocarbon (14C) dates with accelerator mass spectrometry (AMS) of vascular plant samples and a charcoal sample collected from peat deposits near the prehistoric village site informally designated CR-03 on Carlisle Island in the Islands of Four Mountains group, Alaska, to determine the eruption age of the CR-02 tephra. A fine vitric ash erupted from Okmok caldera, Umnak Island (ca. 2 ka BP) was also discovered in the bog. The ages of the CR-02 tephra and Okmok II ash are estimated to be 1050 and 2000 cal BP, respectively. Because both tephras are distinctive and widespread, these are important chronostratigraphic markers for archaeological sites in this island group. The 14C dates obtained from this bog are 800 years younger than the dates of the charcoal fragments from cultural layers in the Unit 3 of prehistoric village site CR-02 (AMK-0003). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

C dating of human remains from the necropolis overlaying the forum of the Roman city of Pollentia (Mallorca, Balearic Islands, Western Mediterranean) has helped to solve the problem of the chronology of these burials. Traditionally, this necropolis was thought to date from the fourth century AD. Recent archaeological data suggested a later chronology with graves that follow funerary practices considered of the Late Antique Christian communities on the island. The results of the radiocarbon dating provide an unexpected dating from the tenth to the twelfth centuries, well into the Islamic period (AD 902/903-1229). The results are of extreme importance as they offer, for the first time, an absolute chronology for this necropolis. Furthermore, they may provide archaeological evidence of the existence of non-Muslim communities into the Muslim period on the island. This absolute chronology and its implications are a major breakthrough for the history of Pollentia, Mallorca and the Balearics. [ABSTRACT FROM AUTHOR]

Archaeological site 3 in Ulów is in an area previously thought not to have been settled before historical times. Systematic excavation work that began there in 2002 revealed long-term occupation from the Late Palaeolithic to the Middle Ages. The majority of archaeological features represent a cemetery belonging to the Late Roman and Early Migration periods (III–V c. AD, Wielbark culture). The site’s relative chronology was determined from analyses of archaeological artifacts. To complete the chronological framework required for a proper interpretation of cultural processes, a group of charcoal fragments was selected for radiocarbon (14C) dating. These charcoals were first taxonomically identified and weighed, and then designated for accelerator mass spectrometry (AMS) and conventional 14C analyses. The datings (n=43) indicated three main chronological horizons. Some of the graves from the Wielbark culture contained charcoals of younger or older age, posing problems in interpreting taphonomic processes at this multicultural site. In the light of the 14C dating results, the chronology of several features previously attributed to the Wielbark culture was re-interpreted. [ABSTRACT FROM AUTHOR]

Bone is frequently dated in archaeological studies and, especially for very old bones (more than 40,000 years old), it is critical to have an accurate and precise measure of the material-specific background value and its associated uncertainty. The SUERC Radiocarbon Laboratory has obtained a mammoth bone as a background bone standard and an appropriate number are now routinely prepared and measured in each AMS batch, resulting in the accumulation of a large number of background bone results over a two-year period. Additionally, information on which of the two accelerator mass spectrometry (AMS) instruments was used to make the radiocarbon (14C) measurements, and which sample pretreatment method (modified Longin or modified ultrafiltration) was used to extract and purify the collagen, is recorded for each sample. These data have been used to estimate the laboratory bone background (to be subtracted from each unknown bone sample prepared in the laboratory) and its associated analytical uncertainty. The statistical analysis of the bone results has made use of a linear mixed effects model to examine the variation, and to apportion the overall variation between and within batches on both AMS instruments, and the different pretreatment methods used at SUERC. [ABSTRACT FROM AUTHOR]

The Cave of Pan is located on the N/NE slope of the hill of Oinoe (38°09′31.60′′N, 23°55′48.60′′E), west of modern Marathon. In rescue excavation campaigns during the last three years, among other finds, charcoal and seashell samples were also collected. The purpose of this study is the accelerator mass spectrometry (AMS) dating of the cave’s anthropogenic deposits and the calculation of the regional marine reservoir effect during the Neolithic period. For that purpose, 7 charcoal pieces and 1 seashell were dated. Our results show that the cave was used from the second quarter of the 6th millennium (Middle Neolithic period) until the beginning of the 5th millennium BC. Additionally, one sample collected from a depth of 2 cm from the present surface of the cave yielded an age falling within the 6th century AD, giving thus the absolute time span of the cave use. Moreover, the radiocarbon (14C) ages of one pair of charcoal-seashell samples showed that the marine reservoir age R(t) in the estuarine Marathon Bay region during the 5th millennium BC is 775±57 yr and the local sea surface reservoir deviation ΔR is found to be 402±63 14C yr (within 1σ). [ABSTRACT FROM AUTHOR]

This paper presents the results of the first broad-scale study of modern freshwater reservoir effects (FREs) in various regions of the Eurasian Steppe, associated with archaeological sites. The aim of this work was not only to demonstrate the widespread variability of modern FREs in the region, but also to draw the attention of specialists working in the area to the necessity of taking into account this important and still not fully understood factor involving radiocarbon dating of human and some faunal remains from archaeological sites. To identify modern FREs, modern fish of different species from 10 regions of Siberia and Kazakhstan have been subjected to accelerator mass spectrometry radiocarbon (AMS 14C) dating and stable carbon and nitrogen isotope analysis, and the results are compared with the existing data from previous research. Freshwater reservoir offsets have been detected in all analyzed regions, with the exception of Kharga Lake (Buryatia, Russia) and Kyzylkoi River (central Kazakhstan), varying not only between, but also within regions depending on fish species. The most significant offset in this study has been recorded for the Chuya River basin (Altai Mountains, 1097±40 14C yr), though not as high as observed in previous research for the Caspian lowlands (1477±52 and 1037±52 14C yr) and Upper Lena River basin (Lake Baikal area, 1981±30 14C yr). Both δ13C and δ15N values have been measured with the majority of samples reflecting C3 ecology of local reservoirs and δ15N depending on the diet of particular species, with predatory species such as pike, perch, and burbot demonstrating the highest δ15N. No general relationship has been observed between freshwater reservoir offsets and either δ13C or δ15N values of the samples. [ABSTRACT FROM AUTHOR]

The application of radiocarbon dating to determine the geochronology of archaeological sites is ubiquitous across the African continent. Accelerator mass spectrometry has made radiocarbon dating the most precise method to determine the death of living organisms that occurred within the last 50,000 years. However, the method is not without limitations and this review article provides Africanist archaeologists with cautionary insights as to when, where, and how to utilize radiocarbon dates. Specifically, the review will concentrate on the potential of carbon reservoirs and recycled organic remains to inflate apparent age estimates, diagenesis of carbon isotopes in variable pH ecologies, and hot-humid climates and non-climate-controlled archives that can compromise the efficacy of samples. Legacy radiocarbon ages must be critically examined for what method was used to generate the age, and calibration radiocarbon ages from critical periods of African prehistory lack precision to resolve significant debates. A multipronged dating strategy and careful selection of radiocarbon sample materials are advocated from the earliest stages of research design. [ABSTRACT FROM AUTHOR]

In lake sediments where terrestrial macrofossils are rare or absent, AMS radiocarbon dating of pollen concentrates may represent an important alternative solution for developing a robust and high resolution chronology suitable for Bayesian modelling of age-depth relationships. Here we report an application of the heavy liquid density separation approach (Vandergoes and Prior, Radiocarbon 45:479–492, 2003) to Holocene lake sediments from karstic Lake Sidi Ali, Morocco. In common with many karstic lakes, a significant lake 14 C reservoir effect of 450–900 yr is apparent, evidenced by paired dates on terrestrial macrofossils and either aquatic (ostracod) or bulk sediment samples. AMS dating of 23 pollen concentrates alongside laboratory standards (bituminous coal, anthracite, IAEA C5 wood) was undertaken. Concentrates were prepared using a series of sodium polytungstate (SPT) solutions of progressively decreasing density (1.9–1.15 g/cm 3 ) accompanied by microscopic analysis of the resulting residues to allow quantification of the terrestrial pollen content. The best fractions (typically precipitating at 1.4–1.2 g/cm 3 ) yielded dateable samples of 0.5–5 mg (from sediment samples of ∼15 g), with C content typically ∼50% by weight. Terrestrial pollen purity ranges from 29% to 88% ( μ = 67%), reflecting the challenge of isolating pollen grains from common aquatic algae, e.g. Pediastrum and Botryococcus . A Poisson-process Bayesian depositional model incorporating radiocarbon (pollen and macrofossil) and 210 Pb/ 137 Cs data is employed. As all pollen samples incorporate some non-terrestrial organic matter, we assume an exponential outlier distribution treating each pollen concentrate datum as an old outlier and terminus post quem . This approach yields strong data-model agreement, and differences between the prior and posterior age distributions are furthermore consistent with theoretical offsets anticipated for the known reservoir ages and sample-specific terrestrial content. This application of the pollen concentrate dating approach reinforces the importance of microscopic inspection of the residues during the separation and sieving stages. Sample specific differences mean that the pollen concentrate preparation cannot be reduced to a simplistic “black box” protocol, and dating and subsequent age-model development must be supported by detailed analysis of the microfossil content of the sediments. [ABSTRACT FROM AUTHOR]

A radiocarbon (14C) dating technique with accelerator mass spectrometry (AMS) was applied to estimate the year of death and the year of birth of unidentified human remains. Because many of the samples have been preserved in formaldehyde, it was necessary to evaluate the influence of formaldehyde on carbon ages. Samples intentionally preserved in formaldehyde during the known period were measured, and their Δ14C values were compared with results obtained from fresh samples. The influence of formaldehyde on soft tissue was 14 times larger than that on cortical bone. Unfortunately, an effective method for removing the influence of formaldehyde has not yet been found. 14C ages could be obtained only from the samples not preserved in formaldehyde. The years of birth were determined by the ages of the dentin samples, while the years of death were determined by the ages of the bone and soft tissue samples. Multiple sampling from a body provides an advantage in determination of one of two possible ages of a sample obtained using the bomb peak. Victims of the Korean War were ascertained by the year of death. The year of death and the age at death of unidentified bodies were also determined for forensic investigation. [ABSTRACT FROM AUTHOR]

Copyright of Radiocarbon is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report a set of radiocarbon data for the Middle Bronze Age monumental building at Tell el- Burak in Lebanon, dating it to the 19th century b.c., and summarize the relevant archaeological information concerning the stratigraphy and dating of the building. The radiocarbon data from Tell el-Burak is consistent with the high Middle Bronze Age radiocarbon dates recently reported for Tell el-Dab'a in the eastern Nile Delta and with radiocarbon dates for Middle Bronze Age Tel Ifshar in the coastal plain of Israel. A comparison of these radiocarbon dates questions the current (low) Middle Bronze Age absolute chronology of the southern Levant, which is largely based on the stratigraphic sequence of Tell el-Dab'a. Due to open questions in the archaeological dating of Tell el-Dab'a, we argue against using a single site as a main reference for dating the Middle Bronze Age in the Levant and argue for adopting a comprehensive and independent approach based on archaeological, historical, and radiocarbon evidence from all relevant sites. [ABSTRACT FROM AUTHOR]

Exposure age dating using in situ10Be and 26Al is a very useful technique for dating fluvial terraces. This is especially true in semiarid regions where other methods suffer from a paucity of suitable dating materials. This article describes sample preparation procedures and analytical benchmarks established at the Xi’an Accelerator Mass Spectrometry (AMS) Center for the study of in situ10Be and 26Al. Four intercomparison samples were analyzed in the study, using an improved sample preparation method. The exposure age results are shown to be in good agreement with published data, and demonstrate the reliability of the dating method. This article also presents new 10Be and 26Al results from quartz samples collected from a series of fluvial terraces from Guanshan River, along the Qilian Shan, northeastern Tibetan Plateau. The ages of three fluvial terraces from the Jinfosi site are shown to be (56.4±5.3) ka for T3, (10.7±1.0) ka for T2, and (7.2±1.0) ka for T1. The dating results are consistent with published data from the same region (10Be, 14C, and optically stimulated luminescence dating methods). A comparison of high-resolution climate records with age constraints for the terrace formation shows a close relationship between terrace formation and climate change. [ABSTRACT FROM AUTHOR]

We present the first radiocarbon dates of Early Iron Age sites of central Kazakhstan (in total, 24 dates for 16 recently excavated sites). Archaeologically, the sites have been attributed to the Tasmola culture of the Saka period and later Korgantas phase of the early Hun period. The new accelerator mass spectrometry (AMS) 14C dates suggest that the majority of analyzed Tasmola sites belong to the beginning of the 8th–5th century cal BC, while Korgantas dates to the 4th–2nd century cal BC. This corresponds with the latest archaeological data for the region; however, it is somewhat contrary to the traditional perception of the chronology of the Scythian period in central Kazakhstan. The new dates suggest the beginning of the Early Scythian period in the region in at least the late 9th or 8th century BC rather than 7th century BC according to the traditional approach. [ABSTRACT FROM AUTHOR]

In interpreting radiocarbon dating results, it is important that archaeologists distinguish uncertainties derived from random errors and those from systematic errors, because the two must be dealt with in different ways. One of the problems that archaeologists face in practice, however, is that when receiving dating results from laboratories, they are rarely able to critically assess whether differences between multiple 14C dates of materials are caused by random or systematic errors. In this study, blind tests were carried out to check four possible sources of errors in dating results: repeatability of results generated under identical field and laboratory conditions, differences in results generated from the same sample given to the same laboratory submitted at different times, interlaboratory differences of results generated from the same sample, and differences in the results generated between inner and outer rings of wood. Five charred wood samples, collected from the Namgye settlement and Hongreyonbong fortress, South Korea, were divided into 80 subsamples and submitted to five internationally recognized 14C laboratories on a blind basis twice within a 2-month interval. The results are generally in good statistical accordance and present acceptable errors at an archaeological scale. However, one laboratory showed a statistically significant variance in ages between batches for all samples and sites. Calculation of the Bayesian partial posterior predictive p value and chi-squared tests rejected the null hypothesis that the errors randomly occurred, although the source of the error is not specifically known. Our experiment suggests that it is necessary for users of 14C dating to establish an organized strategy for dating sites before submitting samples to laboratories in order to avoid possible systematic errors. [ABSTRACT FROM AUTHOR]

This paper presents the first successful methods for accelerator mass spectrometry (AMS) dating of asphalt-impregnated insect chitin from the Rancho La Brea Tar Pits in southern California. A persistent problem with stratigraphic correlation at this site is that asphalt flows are characteristically intermittent and are really discontinuous, which can result in mixing fossils of quite different ages. Direct 14C dating of specimens circumvents this difficulty but requires a pretreatment method that can produce dates from relatively small samples (<10 mg) of insect cuticle, while successfully removing residual asphalt and sample preparation solvents as well as soil carbon contamination. 14C dating accuracy was verified by comparing dates on insect chitin with ages for seeds and twigs compacted during a rapid entrapment event within a separately dated skull of the Western Camel, Camelops hesternus Leidy. All dates fell within a relatively narrow range of ~40,000–44,000 14C yr BP, suggesting that such methods can be used with confidence on other insect material from this site. Insects are often superior paleoenvironmental indicators for establishing precise data points for climate fluctuations. This is because their lifecycles and present-day climate-restricted geographic distributions are well documented, and unlike migrating mammals and birds, insects offer crucial information about the local environment. Our results are therefore potentially significant for studies of paleoecological and paleoclimatic change within the Los Angeles Basin and coastal southern California, as well as reconstruction of entrapment events at Rancho La Brea. [ABSTRACT FROM AUTHOR]

Archaeologists have traditionally relied upon relative ceramic chronologies to understand the occupational histories of large and socially complex polities in the Maya lowlands. High-resolution accelerator mass spectrometry (AMS) radiocarbon dating can provide independent chronological control for more discrete events that reflect cultural change through time. This article reports results of AMS 14C dating of stratified sequences at the residential group Tzutziiy K’in, associated with the major Maya polity of Cahal Pech in the Belize Valley. Cahal Pech is one of the earliest permanently settled sites in the Maya lowlands (1200 cal BC), and was continuously occupied until the Terminal Classic Maya “collapse” (~cal AD 800). We use Bayesian modeling to build a chronology for the settlement, growth, and terminal occupation of Tzutziiy K’in, and compare our results to chronological data from the monumental site core at Cahal Pech. The analyses indicate that Tzutziiy K’in was first settled by the Late Preclassic period (350–100 cal BC), concurrent with the establishment of several other large house groups and the growth of the Cahal Pech site core. Terminal occupation by high-status residents at this house group occurred between cal AD 850 and 900. This study provides a framework for interpreting patterns of spatial, demographic, and sociopolitical change between households and the Cahal Pech site core. [ABSTRACT FROM AUTHOR]

Radiocarbon investigation of atmospheric PM2.5 aerosol synchronized with 14CO2 observations began in Debrecen in the winter of 2010. The aim of the study was to determine the contemporary and fossil carbon fractions in the aerosol and to set them against the fossil CO2 excess data referring to the same period. The mass of the collected PM2.5 mode on prebaked quartz filters was determined gravimetrically, while its total carbon mass was calculated from the pressure of CO2 gas produced after the combustion of the filters. As a result of the applied sampling and preparation method, the stable, nonvolatile carbon forms were principally studied. 4C measurements of the tiny aerosol bulk samples were performed using the EnvironMICADAS accelerator mass spectrometer at ATOMKI. The sample preparation method was tested using several blanks, standards, and real samples. Test results showed good reproducibility for the applied aerosol sample preparation and accelerator mass spectrometry (AMS) 14C analyses. Atmospheric fossil CO2 excess data were calculated according Levin et al. (2003), using the 14C results of collected CO2 samples measured by the gas proportional counting system at ATOMKI. Mass concentration of PM10 involving the PM2.5 mode in the city air exceeded the daily average of 50 μg/m3 (24-hr limit value in the EU) several times in 2011, mainly during the winter. The results showed that recently derived carbon most likely from domestic wood burning was causing the elevated carbon mass concentration of PM2.5 in Debrecen at the time. In the course of the 1-yr-long continuous and systematic comparison of fossil carbon mass concentration of PM2.5 mode and mole fraction of fossil excess of atmospheric CO2, similar and synchronous trends were observed during the studied period in Debrecen. [ABSTRACT FROM AUTHOR]

The Colorado Creek section of Alaska is an important paleontological site first excavated and reported on in the early 1980s and 1990s. The remains of two individual mammoths (the "Upper" and "Lower"), and elements of horse, bison, and caribou make this a unique faunal assemblage for a region in interior western Alaska, and the western edge of eastern Beringia. The mammoth remains were the only portions of the faunal assemblage radiocarbon dated in the 1980s. The Upper mammoth ages were widespread between 13,000 and 16,200 BP with the older dates being more accepted for the death of the individual. A single age on the Lower mammoth was produced at 22,880 14C yr BP. New accelerator mass spectrometry (AMS) dates generally confirm the accepted ages for the two mammoths and provide more precise ages of 16,200 ± 50 and 22,710 ± 90 14C yr BP for the Upper and Lower mammoths, respectively. AMS dates on caribou and horse are similar to ages on the Upper mammoth and show an overlap in their ecological ranges in interior western Alaska between 16,000 and 17,000 14C yr BP during the Late Glacial, similar to other areas of the state. The sole AMS date on bison produced an infinite 14C age (>43,500 14C yr BP), considerably older than the Upper and Lower mammoths' remains, and indicates that older deposits are present at the site. A dearth of dated Quaternary paleontological specimens from western Alaska hinders our understanding of this region's paleoecology. This study enhances our conception of the geographic and chronological spread of late Pleistocene large terrestrial mammals in Alaska and Beringia. [ABSTRACT FROM AUTHOR]

In 1954, B K Thapar excavated the multicomponent site of Maski (Raichur District, Karnataka) to establish an archaeological sequence for the southern Deccan region of India. Thapar identified four major periods of occupation, now known as the Neolithic (3000-1200 BC), Iron Age (1200-300 BC), Early Historic (300 BC to AD 500), and the Medieval periods (AD 500-1600). Renewed research at the site by the Maski Archaeological Research Project (F.1/8/2009-EE) has investigated the development of social differences and inequalities in south Indian prehistory. This article reports the first ever radiocarbon assays from habitation and megalithic burial contexts in the vicinity of Maski. Accelerator mass spectrometry (AMS) dates of charcoal sampled from exposed occupational strata on Maski's Durgada Gudda hill and subsequent Bayesian analyses indicate that the site was extensively occupied during the 14th century AD, corroborating interpretations of numismatic and inscriptional materials. Associated artifacts with these 14C samples have significant implications for recognizing late Medieval period ceramics and occupation in the region. AMS assays of four charcoal samples from exposed megalithic burials just south of the Durgada Gudda hill, similar to those recognized by Thapar, indicate that burial practices commonly attributed to the Iron Age predate the period, and thus are not precise chronological markers. However, the results also suggest that megalithic burial practices became more labor intensive during the Iron Age, creating a cultural context for the generation of new forms of social affiliations and distinctions through differential participation in the production of commemorative places. [ABSTRACT FROM AUTHOR]

The flame-sealed tube zinc reduction graphitization method has been successfully adapted and optimized for radiocarbon measurements on EnvironMICADAS in the Institute for Nuclear Research of the Hungarian Academy of Sciences, Hertelendi Laboratory of Environmental Studies (ATOMKI HLES). To reduce the cost and treatment time of producing graphite targets from samples of about 1 mg carbon content, we have omitted the titanium hydride (TiH2) reagent and used a decreased amount of zinc as the sole reductant in our new method. These changes have also helped to eliminate methane formation during the graphitization processes as well as to recover higher ion current at the same background level. These conditions have led to improved efficiency in the 14C measurements; furthermore, the instrument background level remained sufficiently low (<49,000 yr BP). After determining the optimum parameters of the new Zn graphitization method (2.5 mg Fe powder, 15.0 mg Zn powder, 10 hr graphitization at 550°C in heating block, reaction cells with reagent pretreated at 300°C for 1 hr), verification of the accuracy was carried out by the preparation and measurement of IAEA standard samples (C2, C6, C7, C8) with known 14C activity. The sensitivity of the method for gas contamination was tested and determined by comparing the results to measurements of reserved portions of previously processed real samples. [ABSTRACT FROM AUTHOR]

The application of Bayesian models to suites of radiocarbon dates can provide important refinements over standard approaches toward calibration and seriation of dated feature contexts. We have modeled a number of older radiocarbon dates submitted in the 1980s along with a recent set of accelerator mass spectrometry dates from the Averbuch site (40DV60), a Mississippian village in the Middle Cumberland Region of Tennessee occupied in the fourteenth and fifteenth centuries A.D. The results of these analyses demonstrate that even within its short lifespan of ca. 200 years, the village underwent fundamental organizational changes. These shifts appear to be responses to climatic deterioration and an upsurge in regional violence. [ABSTRACT FROM AUTHOR]

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

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

Residue analyses on stone artefacts have contributed to resolving functional questions in stone tool research. Although identifying the function of tools through the analysis of their micro-residues is possible, the establishment of a sound numerical chronology for stone tools lacking a clear stratigraphic sequence, such as surface scatters, remains a challenge. While radiocarbon dating of blood residue on stone artefacts has been published previously ( Loy 1987 , 1990 , 1993 ; Loy et al., 1990 ; Nelson et al.1986 ), this paper reports on an experiment designed to assess the possibility of directly dating residues on stone artefacts by accelerator mass spectrometry (AMS) based radiocarbon measurements. Innovative with this approach is (1) the use of mid and late Holocene pre-dated plant material (wood and peat), processed with contemporarily manufactured stone flakes under controlled laboratory conditions and (2) the use of very small carbon masses (less than 22 µg) for radiocarbon dating. The 14 C results of the wood residues are in excellent agreement with the original sample, whereas the 14 C results of the peat residues yield a wider age variation as expected due to the inhomogeneity of the material, but nevertheless, provided dates within an expected age range. Preliminary results demonstrate the feasibility of dating very small amounts of plant residue on lithics directly when contaminants are confined. [ABSTRACT FROM AUTHOR]

This study presents accelerator mass spectrometry (AMS) radiocarbon dates and pollen assemblages of 400-cm core sediments collected from the Karekare Swamp in Rarotonga, Southern Cook Islands, to investigate vegetation changes on the island, in particular those induced by human impacts. Eight 14C dates of charcoal and higher plant fragment samples indicate that the sediments accumulated since ~6.0 cal kBP, with an apparent interruption of deposition (hiatus) from 130 to 132 cm in depth, corresponding to ~2.8 to 0.7 cal kBP. The appearance of Chenopodiaceae pollen from upland weeds, and Cucurbitaceae and Vigna pollen grains from cultivated plants suggest that human influence existed in core sediments above 130 cm in depth. The increased abundance of Pandanus pollen and monolate-type fern spores also implies the existence of human activity. [ABSTRACT FROM AUTHOR]

This article presents the pretreatment protocols for wood samples processed at the Oxford Radiocarbon Accelerator Unit (ORAU), including recent implementation of a purification method to α-cellulose for non-routine samples. We examine the long-term reproducibility of measurement on wood samples at ORAU through the >1000 14C determinations made on known-age tree-ring standards processed in each AMS wheel since our present High Voltage Engineering Europa (HVEE) AMS system came on-line in September 2002. A discussion of background measurements is also provided. [ABSTRACT FROM AUTHOR]

Since 1994, our team has gained extensive experience applying accelerator mass spectrometry (AMS) radiocarbon analysis for mortar dating, totaling over 465 samples and 1800+ measured CO2 fractions. Several samples have been analyzed repeatedly. The research covers both Medieval and Classical archaeology. We therefore believe our experience can be helpful when developing preparation procedures for different kinds of mortars in different areas and in varying chronologies. So far, the main areas of interest have been (a) the churches of the Åland Islands (in the archipelago between Finland and Sweden); (b) the churches in the Åboland Archipelago (SW Finland); (c) sites in the Iberian Peninsula including Torre de Palma (a Roman village in Portugal); and (d) Rome, Pompeii, and Herculaneum (Italy). Most of the analyses before 2000 were hydrolized in only two CO2 fractions per sample, and reliability criteria were defined on the basis of how well the ages of the two fractions agree with each other. These criteria have proved most helpful in determining the reliability of 14C mortar analyses. Different types of mortar have been investigated, including lime mortars made both from limestone and marble, pozzolana mortars, fire-damaged mortars, and mortars based on burnt shells. Most importantly, separate lime lumps sampled from these mortars have been analyzed sporadically and recently more systematically. The research also includes different types of hydrolysis applied in the pretreatment. In addition to using 85% phosphoric acid (H3PO4), the experimental research includes tests with smaller concentrations of phosphoric acid, and tests based on 2-3% hydrochloric acid (HCl) dissolutions. To characterize the dissolution process, results are presented as age profiles of 2-5 CO2 fractions. In our experience, pozzolana mortars have been difficult to date, and HCl dissolution should be used only in special cases and in complementary tests. [ABSTRACT FROM AUTHOR]

Natural textiles provide suitable material for radiocarbon dating. Short-lived organic matter is usually involved and, if 14C dating is applied to pieces that are stylistically well dated, a better understanding of 14C dating of this type of material can be gained. This study presents some examples of dating that support the stylistic dates. Repeated analyses illustrate the robustness of the standard treatment applied to the textiles. [ABSTRACT FROM AUTHOR]

The University of Bern has set up the new Laboratory for the Analysis of Radiocarbon with AMS (LARA) equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) to continue its long history of 14C analysis based on conventional counting. The new laboratory is designated to provide routine 14C dating for archaeology, climate research, and other disciplines at the University of Bern and to develop new analytical systems coupled to the gas ion source for 14C analysis of specific compounds or compound classes with specific physical properties. Measurements of reference standards and wood samples dated by dendrochronology demonstrate the quality of the 14C analyses performed at the new laboratory. [ABSTRACT FROM AUTHOR]

The Chumash village of Qshiwqshiw, located on eastern Santa Rosa Island, is described in ethnographic sources as one of the largest Chumash villages on the northern Channel Islands, with 4 chiefs and 119 baptisms according to mission records. The village is thought to correlate with 2 archaeological sites (CA-SRI-85 and CA-SRI-87) that contain large and dense shell-midden deposits. Despite the importance of these sites for helping understand Late (650–168 cal BP) and Historic (AD 1769–1830) Period Chumash lifeways, only limited surface collections, one small column sample, and 4 radiocarbon dates were previously available, leaving unanswered important questions about the chronology and structure of these sites. To help fill these gaps, we recently excavated, mapped, and obtained several new radiocarbon dates for CA-SRI-85 and CA-SRI-87. Radiocarbon dating and artifact analyses demonstrate that CA-SRI- 85 served as an important Late Period village that had continued occupation into the Historic Period. Additional radiocarbon dates and glass beads confirm that CA-SRI-87 was likely the epicenter of Historic Period occupation, but testing also revealed that the site was occupied about 3000 years ago. The data paint a complex occupational history for both sites and provide the chronological and spatial context for future investigations into the historical ecology and cultural landscape of eastern Santa Rosa Island. [ABSTRACT FROM AUTHOR]

Fifteen accelerator mass spectrometry (AMS) radiocarbon dates obtained on small subsections of archaeological and historical Crassostrea virginica (eastern oyster) shells provide a means to test for intrashell variability in 14C content in late Holocene Chesapeake Bay mollusks. Although salinity and temperature vary considerably throughout the year, the Chesapeake Bay generally lacks the strong coastal upwelling present in the eastern Pacific where intrashell 14C variability is significant. Intrashell variability in Chesapeake Bay C. virginica is between ~60-100 14C yr, considerably smaller than the 120-530 14C yr ranges noted for shells from strong upwelling zones. As a precaution, we follow Culleton et al. (2006) and argue that large subsamples of shells across multiple growth increments are ideal for AMS 14C dating of mollusks to offset potential issues of intrashell 14C variability. [ABSTRACT FROM AUTHOR]

Archeological artifacts such as burial and embalmment materials are commonly dated by 14C labeling using accelerator mass spectrometry (AMS). The presence of contaminant organic matter can interfere with the accurate determination of an object's age, hence sample preparation is a critical step before radiocarbon-based dating. Both harsh acid and base treatments have been applied to remove contamination, such as humic acids, resin-based adhesives, and plant oils. Additional removal of carbon-laden material can also be affected by applying such methods as plasma oxidation. In this study, SC-CO2 with addition of a cosolvent has been applied to remove the above materials prior to plasma oxidation and subsequent dating via AMS. Initially, wood/charcoal samples were extracted using a modified-Isco SFX-2-10 extraction unit (Isco Inc., Lincoln, NE). Experiments were conducted using supercritical carbon dioxide/10% methanol at a pressure of 20.4MPa (3000psig) (p r =2.80) and 40°C (T r =1.36), and carbon dioxide flow rates of ∼1.4±0.1ml/min. Comparison of the SC-CO2–methanol cosolvent treatment with traditional acid–base–acid sample pretreatment on identical wood-charcoal samples showed comparable radiocarbon dating results encompassing a period of 10,000 years. In addition, both Russian and Egyptian mummy gauzes and Russian textiles were similarly treated and the extracts analyzed by MALDI-TOF-MS and GC/MS to determine the chemical identity of the extracted material. A polyglycerol-based polymer was positively identified in addition to fatty acid moieties as their fatty acid methyl ester derivatives (FAMES), which potentially formed from the in situ reaction of the triglycerides present in the embalment materials with the SC-fluid mixture. Model extractions from spiked-linen gauze samples have verified removal of such materials as beeswax, coconut oil, frankincense, glycerol, and humic acids in varying amounts. Application of supercritical fluid extraction (SFE) appears to be a promising method to pretreat small samples for 14C radiocarbon dating where conservation of the archeological artifact is of importance. The SFE pretreatment has the potential to replace harsh acid–base pretreatment methods, and can be coupled with a non-destructive argon or oxygen plasma treatment for microgram carbon removal prior to accelerator MS isotope ratio age determination of the archeological artifact. This combination of techniques requires as little as 0.05mg of carbon-equivalent weight for the age determination of the artifact while minimizing sample degradation. [ABSTRACT FROM AUTHOR]

Ceramics typologies have long been used to build artifact, site, and regional chronologies. Direct accelerator mass spectrometry (AMS) 14C dating of shell-tempered ceramics offers a promising tool for updating and improving these chronologies . Few studies have 14C dated shell fragments from shell-tempered pottery, however, and questions remain about potential biases from "old shell," the reservoir effect, and other variables. Forty-five direct AMS ,4C assays on shell-tempered pottery and associated shell, charcoal, and bone from nine archaeological sites in Virginia and Maryland provide a framework to test this method. AMS ,4C assays from one site may have problems with old shell, but most of the calibrated direct and associated age estimates overlap. One of our samples is the oldest securely dated shell-tempered pottery in North America at ~1000 cal B.C. Our study demonstrates the promise of AMS, 4C dating shell-tempered pottery for refining ceramic and regional chronologies in coastal and other areas around the world. [ABSTRACT FROM AUTHOR]

Abstract: We summarize how radiocarbon measurements are made using accelerator mass spectrometry. We also discuss some complications inherent in the radiocarbon-dating method when calibrating radiocarbon dates to calendar dates. For example, measurements of radiocarbon (14C) in some types of materials are complicated by a “reservoir effect”, caused by an apparent age of the source reservoir that differs from the contemporary atmospheric surface 14C value. In other cases, mobile carbon sources in nature can produce mixed sources of carbon. We explore these effects and discuss their possible implications for 14C measurements and how we can deal with them. [Copyright &y& Elsevier]

The Chewaucan Cave cache, discovered in 1967 by relic collectors digging in eastern Oregon, consists of a large grass bag that contained a number of other textiles and leather, including two Catlow twined baskets, two large folded linear nets, snares, a leather bag, a badger head pouch, other hide and cordage, as well as a decorated basalt maul. One of the nets returned an Accelerator Mass Spectrometry (AMS) radiocarbon date of 340±40 B.P. The cache has been noted in previous publications, but has never been fully documented. Because of the well-preserved perishables, and the direct association that the artifacts have with each other as a cache or tool kit, the assemblage is an excellent example of late Archaic hunting and textile technology, with basketry consistent with materials produced historically by the Klamath people. [ABSTRACT FROM AUTHOR]

Abstract: Despite the existence of long-lived tree species with excellent tree-ring characteristics, the use of dendrochronological techniques for dating archaeological contexts has been very limited in South America. Recent research in the Bolivian Altiplano of the Central Andes has yielded a network of Polylepis tarapacana chronologies that goes back to the 13th century. This species was regularly used by local populations since pre-Columbian times as raw material for beams, lintels, hooks and other architectural features in houses, storage chambers, and sepulchers. The aim of this study is to argue in favor of the potential of P. tarapacana for providing high resolution dates of significant archaeological events during the pre-Columbian era. The chronology of chullpas (burial towers and storage chambers) in the southern Andean Altiplano is used as a case study. Growth rings from P. tarapacana have provided several centennial-length dendrochronological records including a reference regional chronology covering the last 786 years in the Central Andean highlands. Based on this long reference chronology calendar years were assigned to woody pieces from pre-Hispanic chullpas. Dendroarchaeological results are consistent with contextual evidence and most radiocarbon dates from woody samples and related archaeological items. Our results indicate that P. tarapacana has a high potential for providing annually-resolved tree-ring dates for archaeological contexts in the Altiplano since the early 13th century. [Copyright &y& Elsevier]

Various samples extracted from human tissues (with different radiocarbon turnover rates) of a post-bomb human body were submitted to accelerator mass spectrometry (AMS) 14C dating: hair; a cortical fraction of a skull bone; a trabecular fraction of a pubic symphysis; and enamel extracted from permanent teeth with different dates of formation were analyzed. The analyzed samples showed varying 14C concentrations corresponding to different times of formation or different turnover rates. The implications of the results in forensics studies are discussed. [ABSTRACT FROM AUTHOR]

We performed pollen analysis and accelerator mass spectrometry (AMS) radiocarbon dating on cored sediments (KS0412-3) from Kashibaru Marsh, located in the western part of the Sefuri Mountains in northern Kyushu, southwestern Japan, to investigate environmental change around the marsh. Sediment accumulation began in this marsh around cal AD 1200 and continued with an estimated average sedimentation rate of about 4 mm/yr. Human rice cultivation at this location began around cal AD 1300 and was abandoned due to the deposition of a thick sand layer at around cal AD 1400. Since this event, the area has been maintained as a "natural" marsh. [ABSTRACT FROM AUTHOR]

Tree-ring samples were taken from a from a pine tree (Pinus pinea) growing in Villar de Peralonso, a rural area 50 km west of the city of Salamanca, Spain. All samples were processed to extract ?-cellulose and the radiocarbon concentration in each annual ring was measured using accelerator mass spectrometry (AMS) at the University of Nagoya, Japan. The data set covers a growth period between 1979 and 2006, and represents the concentrations of 14C in a "clean area." The average difference between 14C concentrations in Villar de Peralonso and NH zone 1 for the period 1979-1999 is 4.1 ± 1.3‹. A sample was taken to obtain the reference level of 14C for the Iberian Peninsula, for a study of anthropogenic emission of CO2 in urban areas. As part of the initial study, 14C concentration data in tree rings from the city of Valladolid were used to recalculate the fossil fuel component (cfoss) using reference data from Villar de Peralonso. [ABSTRACT FROM AUTHOR]

The Neolithic in Korea began around 10,000 BP and is the period when many substantial changes appear in the archaeological record. In particular, one of the important changes is from a subsistence strategy that relied primarily on hunted, fished, and collected food packages to a diet that by the beginning of the Bronze Age (~3500 BP) saw intensive agriculture as the primary form of sustenance. This paper discusses current research on this topic, in addition to presenting a comprehensive list of raw accelerator mass spectrometry (AMS) data from Korean Neolithic sites, particularly data that only became available over the past several years. [ABSTRACT FROM AUTHOR]

Four accelerator mass spectrometry (AMS) facilities undertook an interlaboratory exercise designed to examine the reliability and reproducibility of radiocarbon determinations on bone by dating a sample of elk (Alces alces) from Miesenheim IV. This specimen is derived from a secure geological context directly beneath the Laacher See tephra, which provides a precise terminus ante quem of ~11,060 yr BP (~13,050 cal yr BP). Regrettably, the results of the intercomparison exercise were complicated by evident contamination of the bone sample by exogenous organic material. This contaminant, probably humic acid, resulted in a wide span of ages (10,010 ± 30 to 11,100 ± 45 BP). The only method that yielded an accurate determination, consistent with the age of the tephra, was Oxford's single amino acid technique, which targets hydroxyproline. An acid hydrolysis step seems to have been crucial in breaking the bonds between the bone collagen and the contaminant. [ABSTRACT FROM AUTHOR]

The ancient Egyptian mummy discovered in the wooden coffin of Ankhpakhered, priest of the god Min, has been studied at CEDAD (Centre for Dating and Diagnostics) at the University of Salento, Italy. The CT scan, performed by the multidisciplinary team of the Mummy Project of Milan, highlighted unusual features of the mummy, suggesting a reuse of the sarcophagus. Furthermore, specimens were taken via endoscopy for accelerator mass spectrometry (AMS) radiocarbon dating and Fourier transform infrared (FTIR) analyses, which have been carried out at CEDAD. [ABSTRACT FROM AUTHOR]

Lower Congo rock art is concentrated in a region that stretches from Kinshasa to the Atlantic coast and from northern Angola to southern Congo-Brazzaville. Although Lower Congo rock art was identified as early as the 19th century, it had never been a subject of thorough investigation. Presently inhabited by the Ndibu, one of the Kongo subgroups, the Lovo Massif is situated north of the ancient Kongo Kingdom. With 102 sites (including 16 decorated caves), the massif has the largest concentration of rock art in the entire region. In 2008 and 2010, we were able to collect pigment samples directly on the panels of the newly discovered decorated cave of Tovo. Unlike the Sahara and southern Africa, both extensively prospected, rock art of central Africa is still widely unknown and not dated. Radiocarbon dating of rock art in Africa is a real challenge and only a few direct dates have been obtained thus far. After verifying that the pigment samples were indeed charcoal, we proceeded to 14C date them using accelerator mass spectrometry (AMS). The results indicate dates between cal AD 1480 and 1800, confirming that the occupation of Tovo Cave was contemporaneous with the ancient Kongo Kingdom. [ABSTRACT FROM AUTHOR]