bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Application of Bomb Carbon in Teeth for Forensic Investigation
Authors: Wang N , Shen C D , Ding P , Yi W X , Sun W D , Liu K X , Ding X F , Fu D P , Yuan J , Yang X Y , Zhou L P
Published: July 2016

While radiocarbon is widely applied in dating ancient samples, recent studies reveal that 14C concentrations in modern samples can also yield precise ages due to the atmospheric testing of thermonuclear devices between 1950 and 1963. 14C concentrations in both enamel and organic matter of 13 teeth from 2 areas in China were examined to evaluate and improve this method of forensic investigation. Choosing enamel near the cervix of the tooth can reduce the error caused by the difference between the sample formation time and whole enamel formation time because tooth enamel formations take a long time to complete. A proper regional data set will be helpful to get an accurate result when calculating the age of the sample (T1) by the CALIBomb program. By subtracting the enamel formation time (t), the birth date of an individual (T2) can be confirmed by enamel F14C from 2 teeth formed at different ages. Calculated enamel formation dates by 14C concentration are basically consistent with corresponding actual values, with a mean error of 1.9 yr for all results and 0.2 yr for the samples formed after AD 1960. This method is more effective for dating samples completed after AD 1960. We also found that 14C concentrations in organic matter of tooth roots are much lower than atmospheric concentrations in root formation years, suggesting that the organic material keeps turning over even after tooth formation is complete. This might be a potential tool for identification of death age to extract a proper component for 14C dating. We also observed that δ13C values between hydroxyapatite and organic matter indicate that isotopic fractionation during the biomineralization is 8–9%‰ more positive in mineral fractions than in organic matter.
Estimation of Long-Term Trends in the Tropospheric 14CO2 Activity Concentration
Authors: Svetlik I , Povinec P P , Molnár M , Meinhardt F , Michálek V , Simon J , Svingor É
Published: July 2016

Fossil CO2 emissions have been diluting the global 14C/C ratio of atmospheric CO2 (Suess effect). We estimated the 14CO2 amount in the atmosphere (and its trend) utilizing the calculated 14CO2 activity concentration in the atmosphere (aacn, reported in mBq m–3). This parameter, calculated from Δ14CO2 and the CO2 mixing ratio (reported in micromoles of CO2 per mole of air), is connected with the 14CO2 quantity in the volume or mass unit of air, which is not influenced by the Suess effect. This parameter can only be influenced by processes linked to 14CO2 emissions/uptake, e.g. associated with atmosphere-biosphere or atmosphere-ocean CO2 exchange as well as by anthropogenic emissions of 14CO2. Results obtained from measurements at Schauinsland station, Germany, indicate a stable amount of 14CO2 in the atmosphere since the early 1990s.
Radiocarbon in the Air of Central Europe: Long-Term Investigations
Authors: Svetlik I , Povinec P P , Molnár M , Vána M , Šivo A , Bujtás T
Published: July 2016

Regional levels of radiocarbon have been monitored in order to investigate the impact of fossil fuel combustion on the activity of atmospheric 14CO2 in central Europe. Data from atmospheric 14CO2 monitoring stations in the Czech Republic, Slovakia, and Hungary for the period 2000–2008 are presented and discussed. The Prague and Bratislava monitoring stations showed a distinct local Suess effect when compared to the Jungfraujoch clean-air monitoring station. However, during the summer period, statistically insignificant differences were observed between the low-altitude stations and the high-mountain Jungfraujoch station. 14C data from the Hungarian monitoring locality at Dunaföldvár and the Czech monitoring station at Košetice, which are not strongly affected by local fossil CO2 sources, indicate similar grouping and amplitudes, typical for a regional Suess effect.
Robust Bayesian Analysis, an Attempt to Improve Bayesian Sequencing
Authors: Weninger Franz , Steier Peter , Kutschera Walter , Wild Eva Maria
Published: July 2016

Bayesian sequencing of radiocarbon dates deals with the problem that in most cases there does not exist an unambiguous way to define the so-called prior function, which represents information in addition to the result of the 14C measurements alone. However, a random choice of a particular prior function can lead to biased results. In this paper, “robust Bayesian analysis,” which uses a whole set of prior functions, is introduced as a more reliable method. The most important aspects of the mathematical foundation and of the practical realization of the method are described. As a general result, robust Bayesian analysis leads to higher accuracy, but paid for with reduced precision. Our investigations indicate that it seems possible to establish robust analysis for practical applications.
Characterization and Dating of Saline Groundwater in the Dead Sea Area
Authors: Avrahamov Naama , Yechieli Yoseph , Lazar Boaz , Lewenberg Omer , Boaretto Elisabetta , Sivan Orit
Published: July 2016

This work presents an attempt to date brines and determine flow rates of hypersaline groundwater in the extremely dynamic system of the Dead Sea (DS), whose level has dropped in the last 30 yr by ∼20 m. The processes that affect the carbon species and isotopes of the groundwater in the DS area were quantified in order to estimate their flow rate based on radiocarbon and tritium methods. In contrast to the conservative behavior of most ions in the groundwater, the carbon system parameters indicate additional processes. The dissolved inorganic carbon (DIC) content of most saline groundwater is close to that of the DS, but its stable isotopic composition (δ13CDIC) is much lower. The chemical composition and carbon isotope mass balance suggest that the low δ13CDIC of the saline groundwater is a result of anaerobic organic matter oxidation by bacterial sulfate reduction (BSR) and methane oxidation. The radiocarbon content (14CDIC) of the saline groundwater ranged from 86 pMC (greater than the ∼82 pMC value of the DS in the 2000s) to as low as 14 pMC. The similarity between the 14CDIC value and Na/Cl ratio of the groundwater at the DS shore and that of the 1980s DS brine indicates that the DS penetrated to the aquifer at that time. The low 14CDIC values in some of the saline groundwater suggest the existence of ancient brine in the subaquifer.
Spatial Variation in the Marine Radiocarbon Reservoir Effect Throughout the Scottish Post-Roman to Late Medieval Period: North Sea Values (500–1350 BP)
Authors: Russell N , Cook G T , Ascough P L , Dugmore A J
Published: July 2016

The marine radiocarbon reservoir effect (MRE) occurs as a spatially and temporally dependent variable owing to localized changes in oceanic water composition. This study investigates ΔR values (deviations from the global average MRE whose ΔR = 0) during the period 500–1350 BP for the east coast of Scotland, where a complex estuarine system exists that drains into the semi-enclosed North Sea basin. Due to the availability of suitable archaeological samples, the data set has a distinct Medieval focus that spans the area from Aberdeen in the north to East Lothian in the south. Many of the ΔR values are not significantly different from 0 (the global average), but there are occasional excursions to negative values (max –172 ± 20) indicating the presence of younger water. These values show greater variability compared to other published data for this general region, suggesting that considerable care must be taken when dating marine derived samples from archaeological sites on the east coast of Scotland.
Report on the 20th International Radiocarbon Conference Graphitization Workshop
Authors: Turnbull Jocelyn , Prior Christine ,   Graphitization Workshop Participants
Published: July 2016

A sample preparation workshop was convened at the 20th International Radiocarbon conference, with about 30–40 attendees. The term “sample preparation” was not further specified to allow participants to address the laboratory issues most important to them. Given the short time available, the focus quickly narrowed to details of graphite preparation for accelerator mass spectrometry (AMS), with particular interest in procedures for small samples, and hence we have changed the title to reflect the focus. Here, we summarize the workshop discussion, adding additional background information and references to publications. Several aspects of graphite preparation are included: catalyst types and ratio of catalyst to carbon; optimal reaction temperatures for various sample sizes; methods for water removal; types of pressure transducers; preconditioning of catalyst; and problems with blank values in very small samples. The pros and cons of sample dilution were also discussed.
Establishment of Chemical Preparation Methods and Development of an Automated Reduction System for AMS Sample Preparation at Kigam
Authors: Hong Wan , Park Jung Hun , Kim Kyeong J , Woo Hyung Joo , Kim Jun Kon , Choi Han Woo , Kim Gi Dong
Published: July 2016

Many previous studies on the sample preparation of various kinds of radiocarbon dating samples by accelerator mass spectrometry (AMS) have been examined at KIGAM (Korea Institute of Geoscience and Mineral Resources) and our own procedures have been established. Furthermore, an automated reduction system has been developed. The volume of the reduction region was minimized to improve the reduction yield, and air-actuated pneumatic valves and solenoid arrays were used for computer control of the system. Operation of all the valves and vacuum pumps and signals from the temperature sensors and pressure gauges were interfaced to a personal computer with an A/D board. A computer program was also developed to perform automatic operation of the reduction system. This system consistently shows a higher reduction yield than 90%. The reduction time of the system is currently 140 min.
Simple Pretreatment Method Development for Iron and Calcium Carbonate Samples
Authors: Park Junghun , Hong Wan , Woo H J , Choi Han Woo , Kim Joonkon , Kim Gi Dong
Published: July 2016

Since iron artifacts generally contain trace amounts of carbon, an iron sample needs to be relatively large, as compared to other materials, and a specially designed combustion system is required. An elemental analyzer (EA) was used for the combustion of iron without any special chemical treatment. CO2 gas with 1 mg of carbon was obtained from the combustion of an iron artifact by using an EA and reduced to graphite for accelerator mass spectrometry (AMS) measurement. In this work, AMS dating results done at the Korea Institute of Geoscience and Mineral Resources (KIGAM) for several ancient iron artifacts are presented and compared with independently estimated ages. This method was found to be useful for the pretreatment of iron artifacts that contained >0.1% carbon. A simple pretreatment method using an EA was also applied to calcium carbonate (CaCO3) samples. Samples were preheated overnight at 100–300 °C, without any special chemical treatment. This removed modern CO2 contamination and the background level decreased to a comparable value measured in samples treated with phosphoric acid under vacuum.
Alternative Methods for Cellulose Preparation for AMS Measurement
Authors: Němec Mojmír , Wacker Lukas , Hajdas Irka , Gäggeler Heinz
Published: July 2016

The main methods applied to clean plant material for radiocarbon dating are not compound-specific and generally remove only the easily exchangeable components by an acid-base-acid sequence and additional optional steps like Soxhlet extraction to remove resins and oxidative bleaching with NaClO2. The products are normally clean enough for standard 14C measurement, but in some cases it is desirable to have pure cellulose, which remains unchanged and immobile over longer time ranges, better representing the original plant material. In this work, 2 more compound-specific but still simple methods were tested to separate the cellulose from wood. The viscose method is based on the xanthification process used in the textile industry, where the alkali-cellulose with CS2 forms a soluble cellulose xanthate, which is then extracted and cellulose is recovered. The second procedure is based on the wood/cellulose dissolution in ionic liquid 1-butyl-3-methylimidazolium chloride [BMIM]Cl, when the dissolved cellulose could be precipitated again by simply adding a water-acetone mixture. This process was recently reported, but still not used in sample preparation procedures for 14C dating.
14C Dating of Holocene Soils from an Island in Lake Pumoyum Co (Southeastern Tibetan Plateau)
Authors: Watanabe Takahiro , Matsunaka Tetsuya , Nakamura Toshio , Nishimura Mitsugu , Sakai Takahiro , Lin Xiao , Horiuchi Kazuho , Nara Fumiko Watanabe , Kakegawa Takeshi , Zhu Liping
Published: July 2016

Soil samples from an 85-cm-long continuous section (PY608ES) were collected from an island in Lake Pumoyum Co (southeastern Tibetan Plateau, ∼5020 m asl) in August 2006. To estimate past environmental conditions of Lake Pumoyum Co during the Holocene, we analyzed radiocarbon ages, stable carbon isotope compositions, and total organic carbon/total nitrogen (TOC/TN) atomic ratios of the soil samples. The 14C measurements were performed with the Tandetron accelerator mass spectrometry system at the Center for Chronological Research, Nagoya University. The 14C concentration in the surface layer (101 pMC; 5–10 cm soil depth) was nearly modern. A 14C chronology of the sequence indicated that continuous soil development began on the island in Lake Pumoyum Co at ∼5800 cal BP (at 63 cm soil depth, the top of a gravel layer). These results may reflect a decrease in the lake level in the middle Holocene. The age of the obvious lithologic boundary (∼5800 cal BP) corresponds to the end of Holocene climate optimum.
AMS Radiocarbon Dating of Holocene Tephra Layers on Ulleung Island, South Korea
Authors: Okuno Mitsuru , Shiihara Miki , Torii Masayuki , Nakamura Toshio , Kim Kyu Han , Domitsu Hanako , Moriwaki Hiroshi , Oda Motoyoshi
Published: July 2016

Ulleung Island, a large stratovolcano, is located in the western part of the Japan Sea (East Sea), 130 km off the eastern coast of the Korean Peninsula. The Ulleung-Oki (U-Oki) is a widely distributed tephra in and around the Japan Sea, and has an age of 10.7 cal ka BP obtained from the Lake Suigetsu data set (central Japan). Of the 7 tephra layers (U-7 to -1) on the island, the pumiceous U-4, U-3, and U-2 tephra layers are petrochemically and petrographically similar to the U-Oki tephra. To determine the eruption ages of 3 tephra layers on Ulleung Island, we conducted radiocarbon dating for 5 soil and 2 charcoal samples. Although the soil samples have the C/N ratios from 5 to 10, the obtained 14C dates are still consistent with the tephra stratigraphy of the island. The calibrated 14C dates for the U-4, U-3, and U-2 tephras are 11 cal ka BP, 8.3 or 9 cal ka BP, and 5.6 cal ka BP, respectively, indicating that the explosive eruptions occurred in the island with a time interval of 2000 to 3000 yr during the period of the early to middle Holocene. Based on our chronology, the U-4 tephra is most likely correlated with the U-Oki tephra.
Development and Application of the Trapezoidal Model for Archaeological Chronologies
Authors: Lee Sharen , Ramsey Christopher Bronk
Published: July 2016

Single- and multiphase models have been used extensively in construction of chronologies. We model more gradual transition between phases with a trapezoid model since it better reflects the nature of the information that goes into the model prior. We find that a simple trapezoid model has a bias that docs not reflect prior knowledge, and thus propose an addition of a noninformative clement to the prior. We also present an alternative parameterization, which transforms the current abrupt transition model into a model that allows for gradual changes. The addition of a noninformative prior ensures model flexibility. We evaluate these Bayesian models using 2 case studies.
The Marine Radiocarbon Bomb Pulse Across the Temperate North Atlantic: A Compilation of Δ14C Time Histories from Arctica Islandica Growth Increments
Authors: Scourse James D , Wanamaker Alan D , Weidman Chris , Heinemeier Jan , Reimer Paula J , Butler Paul G , Witbaard Rob , Richardson Christopher A
Published: July 2016

Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Δ14C excess from known-age annual increments of the long-lived bivalve molluskArctica islandicafrom 4 sites across the coastal North Atlantic (German Bight, North Sea; Troms⊘, north Norway; Siglufjordur, north Icelandic shelf; Grimsey, north Icelandic shelf) combined with published series from Georges Bank and Sable Bank (NW Atlantic) and the Oyster Ground (North Sea). The atmospheric bomb pulse is shown to be a step-function whose response in the marine environment is immediate but of smaller amplitude and which has a longer decay time as a result of the much larger marine carbon reservoir. Attenuation is determined by the regional hydrographic setting of the sites, vertical mixing, processes controlling the isotopic exchange of14C at the air-sea boundary,14C content of the freshwater flux, primary productivity, and the residence time of organic matter in the sediment mixed layer. The inventories form a sequence from high magnitude-early peak (German Bight) to low magnitude-late peak (Grimsey). All series show a rapid response to the increase in atmospheric Δ14C excess but a slow response to the subsequent decline resulting from the succession of rapid isotopic air-sea exchange followed by the more gradual isotopic equilibration in the mixed layer due to the variable marine carbon reservoir and incorporation of organic carbon from the sediment mixed layer. The data constitute calibration scries for the use of the bomb pulse as a high-resolution dating tool in the marine environment and as a tracer of coastal ocean water masses.
High-Level 14C Contamination and Recovery at Xi'an AMS Center
Authors: Zhou Weijian , Wu Shugang , Lange Todd E , Lu Xuefeng , Cheng Peng , Xiong Xiaohu , Cruz Richard J , Liu Qi , Fu Yunchong , Zhao Wennian
Published: July 2016

A sample with a radiocarbon concentration estimated to be greater than 105times Modern was inadvertently graphitized and measured in the Xi'an AMS system last year. Both the sample preparation lines and the ion source system were seriously contaminated and a series of cleaning procedures were carried out to remove the contamination from them. After repeated and careful cleaning as well as continuous flushing with dead CO2gas, both systems have recovered from the contamination event. The machine background is back to 2.0 x 10–16and the chemical blank is beyond 50 kyr.
Methodological Implications of New Radiocarbon Dates from the Early Holocene Site of Körtik Tepe, Southeast Anatolia
Authors: Benz Marion , Coşkun Aytaç , Hajdas Irka , Deckers Katleen , Riehl Simone , Alt Kurt W , Weninger Bernhard , Özkaya Vecihi
Published: July 2016

One of the greatest challenges of contemporary archaeology is to synthesize the large amount of radiocarbon and archaeological data into a useful dialogue. For the late Epipaleolithic and the Early Neolithic of the Near East, many14C ages have been published without precise stratigraphic documentation. Consequently, for archaeological age models we often must use some more elementary approaches, such as probabilistic summation of calibrated ages. The stratigraphy of Körtik Tepe allows us for the first time to study an extended series of14C ages of the earliest Holocene. In particular, we are able to analyze the data according to stratigraphic position within a well-documented profile. However, because of a plateau in the14C age calibration curve at the transition from the Younger Dryas to the Early Holocene, dates of this period can be interpreted only if an extended sequence of dates is available. Due to problems remaining in the calibration procedure, the best way to achieve an interpretation is to compare the results of different14C calibration software. In the present paper, we use the results of the calibration programs OxCal and CalPal. This approach has important implications for future age modeling, in particular for the question of how to date the transition from the Epipaleolithic to the PPNA precisely and accurately.
Characterization of Contexts for Radiocarbon Dating: Results from the Early Iron Age at Tell Es-Safi/Gath, Israel
Authors: Toffolo Michael , Maeir Aren M , Chadwick Jeffrey R , Boaretto Elisabetta
Published: July 2016

The reliability of a radiocarbon date depends in part on the degree of precision and accuracy of the measurement. While analytical precision and accuracy can be improved by careful sample cleaning procedures and high laboratory standards, accuracy also depends upon the certainty to which the sample can be attributed to a specific material culture or event in the past. This might be questionable when based only on partial archaeological information. As a consequence, it is very difficult to date clear-cut chronological transitions within specific periods. This issue is particularly apparent in the case of Mediterranean Iron Age chronology, where 2 somewhat different perspectives are proposed, the “High Chronology” and the “Low Chronology,” which differ by ∼50 yr. Here, we present the preliminary results of an ongoing project that aims to characterize Iron Age archaeological contexts from the eastern Mediterranean, and to identify those contexts that are suitable for dating, in order to improve the accuracy of 14C dates. This study involves the analysis of sediments by means of FTIR spectrometry, soil micromorphology, phytolith and phosphate extraction, all of which provide insights into the site-formation and postdepositional processes at the different sites under investigation. These techniques, applied at Tell es-Safi/Gath (Israel), enabled us to better identify a secure context for dating.
A Merovingian Surprise: Early Medieval Radiocarbon Dates on Cremated Bone (Borsbeek, Belgium)
Authors: De Mulder Guy , van Strydonck Mark , Annaert Rica , Boudin Mathieu
Published: July 2016

Radiocarbon dating of cremated bone is a well-established practice in the study of prehistoric cremation cemeteries since the introduction of the method in the late 1990s. 14C dates on the Late Bronze Age urnfield and Merovingian cemetery at Borsbeek in Belgium shed new light on Merovingian funerary practices. Inhumation was the dominant funerary rite in this period in the Austrasian region. In the Scheldt Valley, however, some cremations are known, termed Brandgrubengräber, which consist of the deposition of a mix of cremated bone and the remnants from the pyre in the grave pit. 14C dates from Borsbeek show that other ways of deposition of cremated bone in this period existed. In both cases, bones were selected from the pyre and wrapped in an organic container before being buried. Recent excavation and 14C dates from another Merovingian cemetery at Broechem confirmed the information about the burial rites and chronology from Borsbeek. This early Medieval practice of cremation rituals seems an indication of new arrivals of colonists from northern regions where cremation remained the dominant funerary rite. Another case at Borsbeek shows the reuse of a Late Bronze Age urn in the Merovingian period. This practice is known from Viking burials in Scandinavia, but was not ascertained until now in Flanders.
Preliminary Radiocarbon Analyses of Contemporaneous and Archaeological Wood from the Ansanto Valley (Southern Italy)
Authors: Capano Manuela , Marzaioli Fabio , Passariello Isabella , Pignatelli Olivia , Martinelli Nicoletta , Gigli Stefania , Gennarelli Ida , De Cesare Nicola , Terrasi Filippo
Published: July 2016

The Ansanto Valley (southern Italy) is characterized by hydrothermal phenomena, with volcanic gas emissions arising from some vents. In the 1 st millennium BC, a sanctuary dedicated to the goddess Mephitis was built but later destroyed by landslides in the valley. During archaeological excavations in the 1950s, many items were found including wooden artifacts, preserved thanks to the imbibition and subsequent mineralization of the wood tissues due to the gas emissions. Radiocarbon dating of these objects is underway at CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage), in Caserta, Italy. Unfortunately, 2 main problems arise in dating these materials. The first is possible fossil dilution caused by the CO2 emitted from the nearby volcanic vents, which could affect the trees of the valley and also the archaeological materials. In order to determine the magnitude of the fossil dilution in the area, 14C measurements were performed on contemporaneous wood cored from 2 oak trees growing near the vents. 14C values measured in these samples confirmed the presence of a strong fossil dilution in the Ansanto Valley. The second problem is the restoration that the objects underwent during the last century (mostly by using modern organic substances). To investigate suitable pretreatment procedures for removing the restoration materials from the archaeological findings, contemporaneous wood was also analyzed. The wood of trees from the Ansanto Valley and from a distant village (unaffected by the Ansanto fossil dilution) were submitted to the same restoration process applied to the archaeological artifacts, followed by an “artificial weathering” process. Some archaeological materials were also tested for the removal of restoration materials. We subjected the artificially aged trees and the archaeological samples to different chemical processes. Here, we present the results of these processes. Almost all methods turned out to be suitable for the contemporaneous wood, while the results for the archaeological samples remain uncertain. For this reason, more tests are needed, concerning the “artificial weathering,” the restoration, and the chemical procedure for removing the consolidation materials.
New 14C Dates for the Early Natufian of El-Wad Terrace, Mount Carmel, Israel
Authors: Weinstein-Evron Mina , Yeshurun Reuven , Kaufman Daniel , Eckmeier Eileen , Boaretto Elisabetta
Published: July 2016

The Natufian culture of the southern Levant played an integral role in the transition from simple huntergatherers to food-producing societies of the Neolithic, but the major Natufian hamlets are currently poorly dated. Moreover, none of these complex, continuously occupied base camps have delivered an adequate number of dates to enable an in-depth delineation of intra-Natufian developments. This paper presents the first results of our dating program at el-Wad terrace, Mount Carmel (Israel), one of the major Natufian hamlets of the “core area” of this culture. Thirteen accelerator mass spectrometry (AMS) radiocarbon age determinations were obtained from 46 bone (both ungulate and human) and charcoal samples, originating in Early Natufian living surfaces, dwellings, and burials. The obtained dates are largely in agreement with the cultural affiliation of the samples (13–15 kyr cal BP). Two series of dates from different locations show good agreement with the stratigraphy. The ages of the burials clearly point to their being younger than the living surfaces seemingly associated with them. Presently, no burials may be linked with the major architectural phase of Early Natufian el-Wad. Our ongoing dating program and the processing of additional samples from refined contexts will help shed important light on the initial phases of the Natufian culture, habitation duration, intensity, and continuity, as well as the relationships between site features and stratigraphy.
Plaster Characterization at the PPNB Site of Yiftahel (Israel) Including the Use of14C: Implications for Plaster Production, Preservation, and Dating
Authors: Poduska Kristin M , Regev Lior , Berna Francesco , Mintz Eugenia , Milevski Ianir , Khalaily Hamudi , Weiner Steve , Boaretto Elisabetta
Published: July 2016

The Pre-Pottery Neolithic B (PPNB) site of Yiftahel, Israel, contains abundant plaster floors. We surveyed the states of preservation of the plasters using an infrared spectroscopic assay that characterizes the extent of disorder of the atoms in the calcite crystal lattice. We identified the 3 best-preserved plaster samples that had disorder signatures most similar to modern plaster. We then studied the surface layers, fine-grained matrices, and large aggregates of these samples using micromorphology, Fourier transform infrared (FTIR) microscopy, stable carbon and radiocarbon concentrations. Even though some of the plaster components have a geogenic appearance in micromorphology slides and in FTIR spectra, the14C analyses show that all components were exposed to high temperatures and as a result were equilibrated with the14C content of the atmosphere ∼10,000 yr ago. This implies that the plasters at Yiftahel were produced entirely from heat-altered calcite. We also show that these plasters have undergone significant diagenesis. The plaster component with the most disordered atomic signature, and hence the most similar in this respect to modern plaster, did indeed produce a14C date close to the expected age.
Radiocarbon Reservoir Ages in the Gulf of California: Roles of Upwelling and Flow from the Colorado River
Authors: Goodfriend Glenn A. , Flessa Karl W.
Published: July 2016

We measured apparent radiocarbon ages of live-collected, pre-bomb mollusk shells from the northern and central Gulf of California to determine the source of the reservoir ages and the reservoir age correction offsets for calibrating 14C dates of fossil samples. Reservoir ages average 860 yr in the northern Gulf and 725 yr in the central Gulf. The corresponding ∆R values (the deviation from typical worldwide values) are 540 yr and 395 yr, respectively, with variabilities (SD) of 90 and 110 yr. This variability significantly limits the precision of calibrated 14C ages. The apparent 14C age of Colorado River water (as measured in a freshwater mussel, collected in the 1890s, before diversion of river flow) is not sufficiently high (1420 yr) to account for the high reservoir ages in the Gulf. The lack of a relation between the stable isotope composition of Gulf mollusks and their reservoir ages is further evidence that the Colorado River does not make a significant contribution to Gulf reservoir ages. Upwelling of old, deep Pacific-derived water appears to be the cause of the large reservoir ages.
Reservoir Effect of the Southern and Southeastern Brazilian Coast
Authors: Angulo Rodolfo J , de Souza Maria C , Reimer Paula J , Sasaoka Sueli K
Published: July 2016

A regional marine reservoir correction (ΔR) of 33±24 14C yr for southern Brazil was obtained from 6 marine shell samples collected in the states of Santa Catarina and Paraná. This work also presents a ΔR estimation of 8±17 14C yr for the southern and southeastern Brazilian coast from the states of Rio de Janeiro to Santa Catarina, obtained by including 7 ages published in previous works. The high variability of R in modern and Holocene samples from the Brazilian coast is also discussed.
Radiocarbon Dating of Modern Peat Profiles: Pre- and Post-Bomb14C Variations in the Construction of Age-Depth Models
Authors: Goslar Tomasz , van der Knaap W O , Hicks Sheila , Andrič Maja , Czernik Justyna , Goslar Ewa , Räsänen Satu , Hyötylä Heidi
Published: July 2016

We present studies of 9 modern (up to 400-yr-old) peat sections from Slovenia, Switzerland, Austria, Italy, and Finland. Precise radiocarbon dating of modern samples is possible due to the large bomb peak of atmospheric14C concentration in 1963 and the following rapid decline in the14C level. All the analyzed14C profiles appeared concordant with the shape of the bomb peak of atmospheric14C concentration, integrated over some time interval with a length specific to the peat section. In the peat layers covered by the bomb peak, calendar ages of individual peat samples could be determined almost immediately, with an accuracy of 2–3 yr. In the pre-bomb sections, the calendar ages of individual dated samples are determined in the form of multi-modal probability distributions of about 300 yr wide (about AD 1650–1950). However, simultaneous use of the post-bomb and pre-bomb14C dates, and lithological information, enabled the rejection of most modes of probability distributions in the pre-bomb section. In effect, precise age-depth models of the post-bomb sections have been extended back in time, into the “wiggly” part of the14C calibration curve.

Our study has demonstrated that where annual resolution is concerned, tissues ofSphagnumare the only representative material for14C dating, although even samples of pureSphagnumcollected from a very thin slice of the peat section contain tissues grown in different years, so they integrate the atmospheric14C signal over a period of time. This time period (0.5–8 yr, depending on the site) seems to correlate with the peat accumulation rate, but it also depends on how the sampled peat sections were handled. When constructing age-depth models, for some peat sections we used the strategy of multi-stage14C dating. This led to a drastic reduction in the uncertainty of the age-depth models, by dating only a few additional samples in the profile.

Our study is the first in which peat sections from the late pre-bomb time (AD 1900–1960) have been precisely dated at a high temporal resolution. In this time interval,14C ages of all the samples dated were younger than those derived from the atmospheric calibration curve, apparently due to the effect of integration. Evidently, the determination of calendar ages based on14C dating of single peat samples from that interval may be affected by a serious error if the possibility of integration is ignored.
An Overview of 14C Analysis in the Study of Groundwater
Authors: Geyh Mebus A
Published: July 2016

This paper provides a summary overview of the current state-of-art in the radiocarbon dating of groundwater. While the use of natural 14C measurements in applied hydrogeology still presents a difficult challenge, meaningful dates can be achieved if they are determined and interpreted in conjunction with the analyses of other isotopic species that occur in the natural environment. Although 14C dating of groundwater can be, and often is, carried out as a matter of routine, any specific case study requires its own scientific design and effort. As is widely recognized, and discussed in considerable detail throughout the scientific literature, there are many hydrogeochemical reactions and/or physical processes that can alter the natural 14C enrichment measured in environmental materials. Fortunately, for fresh groundwater resources such effects are in general well defined and therefore of limited significance. The primary challenge in applied groundwater dating is with the development of the appropriate theoretical background against which 14C dates can be used to calibrate numerical analogues of the groundwater system. The hydraulic properties of each of the widely used finite-element models can be well estimated from numerous piezometric data and extrapolations. In contrast, only a few groundwater ages can be provided for the calibration of those models that are complex functions of aging mixture and sometimes also hydrochemical reactions.
Calendar Age of Lisakovsky Timbers Attributed to Andronovo Community of Bronze Age in Eurasia
Authors: Panyushkina Irina P , Mills Barbara J , Usmanova Emma R , Cheng Li
Published: July 2016

We measured radiocarbon ages of 22 decadal replications and 1 bulk group from 5 tree-ring specimens using acid-base-acid pretreatment and accelerator mass spectrometry (AMS). The study has the goal of refining the precision and resolution of a segment of the conventional Bronze Age chronology in the Eurasian steppe attributed to the multicultural community known as Andronovo. The archaeological timbers were gathered from 3 cemeteries at the Lisakovsky cluster of sites in Kazakhstan, where there is a prominent Andronovo occurrence that appears to show evidence of overlapping Alakul and Fedorovo cultures in the southern margin of the Eurasian steppe. The new set of Andronovo calendar dates derived from 14C wiggles and a composite floating tree-ring chronology places the cultural overlap from 1780 to 1660 cal BC. Results indicate older ages of artifacts from the Lisakovsky site than were previously determined by the typological chronology, shifting them from the Late Bronze Age to also include the transition between the Middle and Late Bronze Age. The chronological order of the Lisakovsky cemeteries provides strong evidence of contemporaneity of the Alakul and Fedorovo cultures in the Tobol River Valley for a portion of the 120-yr period of occupation. We discuss an application of the dated Alakul-Fedorovo overlap to the relationship and origin of different groups of the Andronovo community in the Ural region. Our results demonstrate the substantial power that tree rings from Bronze Age timbers provide for developing a precise and highly resolved calendar chronology of prehistoric human occupation in the Eurasian steppe during the 2nd millennium BC.
Ultrafiltration: Boon or Bane?
Authors: Hüls C M , Grootes P M , Nadeau M-J
Published: July 2016

Ultrafiltration of bone collagen, dissolved as gelatin (M ~100,000 D), has received considerable attention as a means to remove small contaminants and thus produce more reliable dates (Brown et al. 1988; Bronk Ramsey et al. 2004; Higham et al. 2006; Mellars 2006). However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used (Bronk Ramsey et al. 2004; Brock et al. 2007; Hüls et al. 2007).

Here, we present results of further ultrafiltration experiments with modern and fossil collagen samples using Vivaspin 20™ and Vivaspin 15R™ ultrafilters. Evidently, the Vivaspin 20 (VS 20) ultrafilter with a polyethersulfone (PES) membrane retains more material in the >30 kD fraction than the Vivaspin 15R (VS 15R) filter with a regenerated cellulose membrane (Hydrosat), which may be related to increased retention of proteins due to suboptimal electrostatic conditions during ultrafiltration with the PES membrane. In addition, this filter type shows clear evidence for contamination with fossil carbon, presumably from membrane fibers, in the <30 kD fraction. Radiocarbon measurements on ultrafiltrated fossil collagen seem to indicate small contributions of modern carbon via glycerin left on and within the filter membranes of both types. Although SEM pictures show film remnants on the fibrous filter structure of cleaned filter membranes, EDX analysis on the VS 20 membrane to not support the assumption this may be glycerin. Our observations indicate the risks and benefits of the use of ultrafiltration in cleaning collagen samples for 14C dating need to be further quantified, especially for the cleaning of fossil bone collagen of good quality samples.
The Spread of the Neolithic in the South East European Plain: Radiocarbon Chronology, Subsistence, and Environment
Authors: Dolukhanov Pavel M , Shukurov Anvar , Davison Kate , Sarson Graeme , Gerasimenko Natalia P , Pashkevich Galina A , Vybornov Aleksandr A , Kovalyukh Nikolai N , Skripkin V V , Zaitseva Ganna I , Sapelko Tatiana V
Published: July 2016

Newly available radiocarbon dates show the early signs of pottery-making in the North Caspian area, the Middle-Lower Volga, and the Lower Don at 8–7 kyr cal BC. Stable settlements, as indicated by “coeval subsamples,” are recognized in the Middle-Lower Volga (Yelshanian) at 6.8 kyr cal BC and the Caspian Lowland at about 6 kyr cal BC. The ages of the Strumel-Gostyatin, Surskian, and Bug-Dniesterian sites are in the range of 6.6–4.5 kyr BC, overlapping with early farming entities (Starčevo-Körös-Criş and Linear Pottery), whose influence is perceptible in archaeological materials. Likewise, the14C-dated pollen data show that the spread of early pottery-making coincided with increased precipitation throughout the forest-steppe area.
The Influences of Hydrology on the Radiogenic and Stable Carbon Isotope Composition of Cave Drip Water, Grotta di Ernesto (Italy)
Authors: Fohlmeister J , Schröder-Ritzrau A , Spötl C , Frisia S , Miorandi R , Kromer B , Mangini A
Published: July 2016

14C and δ13C values of C-containing species in cave drip waters are mainly controlled by the C isotope composition of karst rock and soil air, as well as by soil carbon dynamics, in particular the amount of soil CO2 in the unsaturated soil zone and the process of calcite dissolution. Here, we investigate soil carbon dynamics by analyzing the 14C activity and δ13C values of C dissolved in cave drip water. Monthly over a 2-yr period, we collected drip water from 2 drip sites, one fast and one relatively slow, within the shallow Grotta di Ernesto Cave (NE Italy). The 14C data reveal a pronounced annual cycle. In contrast, the δ13C values do not show an annual pattern and only small interannual variability compared to the δ13C values of soil waters. The annual 14C drip-water cycle is a function of drip-rate variability, soil moisture, and ultimately hydrology.
Radiocarbon Dating of the Mansuri Paleolithic Site, Cheongwon, Korea
Authors: Kim K J , Jull A J T , Yong Kim Ju , Jo Lee Yung , Hong Wan , Hun Park Jung , Joo Woo Hyung
Published: July 2016

Construction of a new science complex in Osong, Cheongwon-gun, Korea, has allowed the investigation of 14 different Paleolithic localities, excavated during 2005–2007. Here, we investigated localities 1 and 12 of the Mansuri Paleolithic site to obtain chronological information using radiocarbon dating. The soil deposition rates varied from 0.09 to 0.15 mm/yr over the period ranging from 33 to 31 kyr BP for locality 1. Locality 12 samples were more recent, <10 ka, and have similar accumulation rates, averaging 0.11 mm/yr. The soil ages of locality 12 were found to be younger than 10 kyr BP. Results for both soil and organic materials at this locality gave much younger ages at shallower depths than the ages expected by the Korean Paleolithic cultural history for this region. Therefore, these more recent deposits may not be associated with the cultural layers and are interpreted to have been hydrologically modified following emplacement. 14C dates of the soil and organic materials at locality 12 confirm that there is evidence for multiple human occupations throughout the last 9 kyr BP.
A Response to Finkelstein and Piasetzky'S Criticism and “New Perspective”
Authors: Mazar Amihai , Bronk Ramsey Christopher
Published: July 2016

The following short paper is a response to criticism by Finkelstein and Piasetzky (2010b), published in the present issue of Radiocarbon, of our 2008 paper in Radiocarbon concerning the evaluation of 14C dates from Iron Age levels in Israel published by Boaretto et al. (2005). We refer to criticism concerning exclusion and inclusion of data. We also evaluate new models suggested by Finkelstein and Piasetzky and in particular their suggestion of regional stages marking the end of the Iron Age in Israel. We also comment on several methodological issues.
Assessing Open-System Behavior of 14C in Terrestrial Gastropod Shells
Authors: Rech Jason A , Pigati Jeffrey S , Lehmann Sophie B , McGimpsey Chelsea N , Grimley David A , Nekola Jeffrey C
Published: July 2016

In order to assess open-system behavior of radiocarbon in fossil gastropod shells, we measured the 14C activity on 10 aliquots of shell material recovered from Illinoian (~190–130 ka) and pre-Illinoian (~800 ka) loess and lacustrine deposits in the Midwestern USA. Eight of the 10 aliquots yielded measurable 14C activities that ranged from 0.25 to 0.53 percent modern carbon (pMC), corresponding to apparent 14C ages between 48.2 and 42.1 ka. This small level of open-system behavior is common in many materials that are used for 14C dating (e.g. charcoal), and typically sets the upper practical limit of the technique. Two aliquots of gastropod shells from the Illinoian-aged Petersburg Silt (Petersburg Section) in central Illinois, USA, however, yielded elevated 14C activities of 1.26 and 1.71 pMC, which correspond to apparent 14C ages of 35.1 and 32.7 ka. Together, these results suggest that while many fossil gastropods shells may not suffer from major (>1%) open-system problems, this is not always the case. We then examined the mineralogy, trace element chemistry, and physical characteristics of a suite of fossil and modern gastropod shells to identify the source of contamination in the Petersburg shells and assess the effectiveness of these screening techniques at identifying samples suitable for 14C dating. Mineralogical (XRD) and trace element analyses were inconclusive, which suggests that these techniques are not suitable for assessing open-system behavior in terrestrial gastropod shells. Analysis with scanning electron microscopy (SEM), however, identified secondary mineralization (calcium carbonate) primarily within the inner whorls of the Petersburg shells. This indicates that SEM examination, or possibly standard microscope examination, of the interior of gastropod shells should be used when selecting fossil gastropod shells for 14C dating.
University of Bonn Natural Radiocarbon Measurements V
Authors: Scharpenseel H. W. , Pietig F.
Published: July 2016

Radiocarbon measurements, mainly on soil and water samples are being continued. Benzene samples are prepared as described earlier (Scharpenseel and Pietig, 1969). By adding another counting unit, the lab. now uses 3 liquid scintillation spectrometers and 4 benzene synthesis lines.
Lyon Natural Radiocarbon Measurements III
Authors: Evin J. , Marien G. , Pachiaudi Ch.
Published: July 2016

The present list includes most of the samples measured since the establishment of the laboratory in 1965 and not yet published in the two previous dates lists.
Radiocarbon Reservoir Ages in the Mediterranean Sea and Black Sea
Authors: Siani Giuseppe , Paterne Martine , Arnold Maurice , Bard Edouard , Métivier Bernard , Tisnerat Nadine , Bassinot Franck
Published: July 2016

We measured apparent marine radiocarbon ages for the Mediterranean Sea, Black Sea, and Red Sea by accelerator mass spectrometry radiocarbon analyses of 26 modern, pre-bomb mollusk shells collected living between AD 1837 and 1950. The marine reservoir (R(t)) ages were estimated at some 390 ± 85 yr BP, 415 ± 90 yr BP and 440 ± 40 yr BP, respectively. R(t) ages in the Mediterranean Sea and Black Sea are comparable to those for the North Atlantic Ocean (<65°N), in accordance with the modern oceanic circulation pattern. The ΔR values of about 35 ± 70 yr and 75 ± 60 yr in the Mediterranean area show that the global box-diffusion carbon model, used to calculate R(t) ages, reproduces the measured marine14C R(t) ages in these oceanic areas. Nevertheless, high values of standard deviations, larger than measurement uncertainties are obtained and express decadal R(t) changes. Such large standard deviations are indeed related to a decrease of the apparent marine ages of some 220 yr from 1900 AD to 1930 AD in both the Mediterranean Sea and the western North Atlantic Ocean.
Radiocarbon Dates of the Institute of Archaeology III
Authors: Semyontsov A. A. , Dolukhanov P. M. , Romanova Ye. N. , Timofeyev V. I.
Published: July 2016

The current list presents samples measured in the radiocarbon laboratory, Leningrad Branch Inst. of Archaeol., Acad. of Sci., USSR, from July 1967 through June 1969. Ages of 85 archaeologic samples of wood, charcoal, and peat have been determined.
Vienna Radium Institute Radiocarbon Dates III
Authors: Felber Heinz , Pak Edwin
Published: July 2016

Measurements have continued with the same proportional counter system, sample pretreatment procedure, methane preparation and measurement, and calculation using a half-life of 5568 ± 30 yr as described previously (R., 1970, v. 12, p. 298-318). Uncertainties quoted are single standard deviations originating from standard, sample, background counting rates and half-life. No C13/C12 ratios were measured.