bluuebunny/crossref_metadata_2025 huggingface dataset:
Gakushuin Natural Radiocarbon Measurements IV
Authors: Kigoshi Kunihiko , Kobayashi Hiromi
Published: July 2016

This list includes many of the datings done from November 1963 to October 1964. The instruments and techniques used for this work are essentially the same as those used previously (Gakushuin III).
Instituto Venezolano De Investigaciones Cientificas Natural Radiocarbon Measurements I
Authors: Tamers M. A.
Published: July 2016

The I.V.I.C. laboratory started operation in December, 1963 using liquid scintillation techniques and the benzene method. The syntheses are carried out in a Packard benzene synthesizer and the solutions counted by a Packard automatic tri-carb spectrometer. For routine dating, a 4 cc counting vial is used with 2 cc benzene coming from the sample being dated and 2 cc commercial toluene added with the PPO and POPOP scintillators.
Miami Natural Radiocarbon Corrections I-III
Authors: Östlund H. Göte , Bowman Albert L. , Rusnak Gene A.
Published: July 2016

A systematic error of calculation has been included in all radiocarbon age figures released from this laboratory (Miami I, II, and III). The error affects dates of all materials, organic and inorganic, terrestrial and marine, in the same way, namely making them about 410 yr too young. Instead of adding to the confusion by correcting the old age figures we preferred to recalculate the dates starting from the measured isotope ratios. Table 1 below reports the correct age figures as calculated in the following way:
University of New South Wales Radiocarbon Dates I
Authors: Green J. H. , Harris Josephine , Neuhaus J. W. G. , Sewell D. K. B. , Watson Maureen
Published: July 2016

The dates listed were obtained using a stainless steel counter with an active volume of 1.3 L and a background of 16.3 cpm at an absolute filling pressure of 152 cm Hg. The present proportional counter in use is made of O.F.H.C. copper, and has an active volume of 1.25 L and a background of 5.2 cpm, at an absolute counter filling pressure of 152 cm Hg. CO2 is used as the counting gas and the counter is filled to a pressure of between 76 cm and 228 cm of Hg (depending on the sample size) at a temperature of 23 ± 0.3°C. The counter is shielded, starting from the top, by 5 cm of lead and 26 cm of iron, and is surrounded by an array of 22 Geiger tubes, and then finally by 2.5 cm of mercury. The thickness of the sides and base is greater than 10 cm of iron. As yet no neutron shielding is used and this probably accounts for the large fluctuations of background with barometric pressure (0.32 cpm per 1 cm Hg change in the pressure).
Usda Sedimentation Laboratory Radiocarbon Dates I
Authors: McDowell L. L. , Ryan M. E.
Published: July 2016

The radiocarbon dating laboratory at the USDA Sedimentation Laboratory was established to supplement current watershed geomorphologic investigations. The principal objective of the program is to provide information on valley aggradation rates and sequences.
UCLA Radiocarbon Dates IV
Authors: Berger Rainer , Fergusson G. J. , Libby W. F.
Published: July 2016

The measurements reported in this list have been carried out in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics during 1964. They are a continuation of the previously reported date lists UCLA I, II and III. The same counting procedure has been continued: CO2 proportional counting at 1 atm of pressure in a 7.5 L counter with three energy channels. Dates have been calculated according to the recommendations of the Fifth Radiocarbon Conference, Cambridge, 1962, on the basis of a radiocarbon half-life of 5568 yr (Godwin, 1962). The modern standard for organic samples has been based on 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background measurements are determined with CO2 derived from marble. The ages of carbonate-containing substances such as shells and tufa have been calculated on the basis of estimates for the corresponding contemporary C14 activity (Broecker and Walton, 1959), as discussed in the respective sample descriptions. New methods of sample preparation are described in context with the date listings.
British Museum Natural Radiocarbon Measurements XII
Authors: Burleigh Richard , Matthews Keith , Ambers Janet , Kinnes Ian
Published: July 2016

The following list consists entirely of dates for archaeologic samples from the British Isles, mainly measured over the period from May 1979 to June 19801. The dates were obtained by liquid scintillation counting of benzene using the laboratory procedures outlined in previous lists (see, eg, BM-VIII, R, 1976, v 18, p 16).
Illinois State Geological Survey Radiocarbon Dates VII
Authors: Liu Chao Li , Coleman Dennis D
Published: July 2016

The following list contains samples of geologic interest that were processed from February 1974 through May 1980 at the Illinois State Geological Survey (ISGS) Radiocarbon Dating Laboratory. The archaeologic samples processed during the same period will be published in our next date list. The benzene liquid scintillation technique was used following laboratory procedures previously reported by Coleman (1973; 1974).
Sample Preparation of Dissolved Organic Carbon in Groundwater for AMS 14C Analysis
Authors: Burr G S , Thomas J M , Reines D , Jeffrey D , Courtney C , Jull A J T , Lange T
Published: July 2016

This study describes a sample preparation technique used to isolate dissolved organic carbon (DOC) in groundwater for radiocarbon analysis using accelerator mass spectrometry (AMS). The goal of the work is to improve our ability to determine groundwater residence times based on 14C measurements of the DOC fraction in groundwater. Water samples were collected from carbonate and volcanic rock aquifers in southern Nevada. Multiple measurements of total dissolved organic carbon (TDOC) in groundwater from one site are used to demonstrate the reproducibility of the analytical procedure. The reproducibility of the method is about one percent (1σ) for a 0.5 mg sample. The procedural blank for the same size sample contains about 1 percent modern carbon (pMC).
The Chemical and Enzymatic Hydrolysis of Archaeological Wood Cellulose and Monosaccharide Purification by High Ph Anion Exchange Chromatography for Compound-Specific Radiocarbon Dating
Authors: Hodgins G W L , Butters T D , Bronk Ramsey C , Hedges R E M
Published: July 2016

Preliminary experiments were carried out on archaeological wood to investigate methods of cellulose hydrolysis and carbohydrate monomer purification for the purpose of compound-specific radiocarbon dating. The Chelford log, a known 14C dead source of wood cellulose, was selected for study in order to investigate the levels of contamination introduced during sample purification. Two methods of hydrolysis were examined, mineral acid hydrolysis and enzyme hydrolysis using cellulase from Penicillium funiculosum. Under the conditions described, enzymolysis was far superior to acid hydrolysis in terms of the glucose monomer yield. Glucose monomer purification was accomplished using high pH anion exchange chromatography with pulsed amperometric detection. This high performance liquid chromatography (HPLC) method does not require sample derivatization and the chromatography products can be collected in water. These characteristics make it potentially well suited to carbon dating applications. 14C dating of chromatographically purified glucose fractions revealed significant levels of contamination had accumulated during both protocols. Glucose contamination from the cellulase enzyme preparation was a major source of contamination within the enzymatically hydrolyzed samples. Ultrafiltration of the enzyme removed some but not all of this contamination. The contamination must be reduced 10-fold before the methodology could be viable for dating. This hydrolysis/HPLC method is also being investigated for 14C dating of other carbohydrate polymers such as chitin.
An Improvement in Preparation of Mortar for Radiocarbon Dating
Authors: Sonninen E , Jungner H
Published: July 2016

An error source in radiocarbon dating of ancient mortar is dead carbon of limestone mixed in the matrix. To eliminate the influence of limestone the difference in feasibility to react with acid between mortar and limestone is used. Since the rate of reaction depends on grain size use of a well-defined grain size can give a better separation between mortar and limestone. We present results for the grain size dependence of reaction rates for several mortar and limestone samples and discuss the application for dating.
Searching Solar Periodicities in the Late Glacial Record of Atmospheric Radiocarbon
Authors: Goslar Tomasz , Tisnérat-Laborde Nadine , Paterne Martine
Published: July 2016

Accelerator mass spectrometry radiocarbon (AMS 14C) dating of the late glacial section of laminated sediments from Lake Gościąż and Lake Perespilno, Poland, performed with time resolution of 20–30 years suggests quasi-periodic oscillations of δ14C. The regularity of oscillations has been checked by the Maximum Entropy and Fast Fourier Transform methods (MEM and FFT), which revealed peaks at 200 and 230 yr. These periods are similar to those found in the high-precision Holocene δ14C record, and attributed to the changing sun. The analytical assessment of the significance of the FFT and MEM peaks is problematic because of non-uniform spacing and various uncertainties in the input data. The significance of the peaks has therefore been studied by the Monte-Carlo method. Because the original data were approximated with a spline function, the amplitude of the MEM and FFT peaks depends on the stiffness of the spline, which is strongly related to the “real” uncertainty of 14C ages. The Monte-Carlo experiments demonstrate that the significance levels of the MEM and FFT peaks also depend on the spline stiffness. Therefore, the existence of solar 14C variations in the Late Glacial remains an open question.
Seasonal Fluctuation of Stable Carbon Isotopic Composition in Japanese Cypress Tree Rings from the Last Glacial Period–Possibility of Paleoenvironment Reconstruction
Authors: Aoki Takahashi Hiroshi , Yonenobu Hitoshi , Nakamura Toshio , Wada Hideki
Published: July 2016

Seasonal variations of δ13C were analyzed for two Japanese cypress trees (Chamaecyparis obtusa), one buried and one living. Both trees were different in age but sampled in areas geographically close to each other in central Japan. A buried cypress with 394 annual rings was excavated from Old Fuji mudflow, the last glacial strata of the dormant Mt. Fuji volcano. The accelerator mass spectrometry (AMS) radiocarbon date of this glacial sample was 18,600 ± 120 BP (NUTA–4884). A living tree stem, which has 192 rings, was cut from the Izu Peninsula in 1986. In order to measure the seasonal δ13C fluctuation, the tree rings were divided equally into three earlywood and one or two latewood consecutive sections. The δ13C value within an annual ring generally increased from the first to the third or fourth sections then decreased in the last section. This pattern of the variation was similar in the glacial and modern samples. The δ13C value within an annual ring seems to be controlled by environmental factors (not plant physiological ones), since there was no isotopic shift in the seasonal δ13C variation at the earlywood-latewood boundary, which was controlled by plant physiology. The result suggests the potential to reconstruct the paleoenvironment within a year using the seasonal δ13C variation, though site-specific conditions such as soil characteristics would also affect to its fluctuation.
Radiocarbon Challenges Archaeo-Historical Time Frameworks in the Near East: the Early Bronze Age of Jericho in Relation to Egypt
Authors: Bruins Hendrik J , van der Plicht Johannes
Published: July 2016

Our stratified radiocarbon dates from EB Jericho (Trench III) on short-lived material are significantly older than conventional archaeo-historical time frameworks. The calibrated14C date of Stage XV Phase li-lii (Early to Middle EB-I Kenyon) is 100–450 years older. Stage XVI Phase lxi-lxii (Early EB-II Kenyon) is 200–500 years older. Stage XVI Phase lxii-lxiii (destructive end EB-II) is 200–300 years older. Stage XVII Phase lxviii a – lxix a (Early EB-III) is 100–300 years older than conventional archaeo-historical time estimates. As the beginning of the Chalcolithic in the Near East has “become” a 1000 years older, from about 4000 in the 1960s to about 5000 BC in current perception based on14C dating, it should not be surprising that the Early Bronze Age and related Egyptian Dynasties also yield14C dates that are older by a few hundred years than current archaeo-historical time frameworks. Egyptian chronology should not be regarded as ultimately fixed. Egyptologists in the first half of the 20th century gave much older dates for the earlier Dynasties. The new14C evidence is overwhelmingly in favor of an older Early Bronze Age and older dates for Dynasties 1–6.
Radiocarbon Datings from the Almaqah Temple of Bar'an, Ma'rib, Republic of Yemen: Approximately 800 cal BC to 600 cal AD
Authors: Görsdorf Jochen , Vogt Burkhardt
Published: July 2016

Ma'rib is the most famous archaeological site in Yemen. The economical importance of Ma'rib resulted from an ecosystem that was based on irrigation and existed already in the second half of the 3rd millennium BC. In the middle of the 8th century BC Ma'rib rose to the capital of Saba and became the economical and cultural center of southern Arabia. In 1975 the German Archaeological Institute began to investigate and document the antique oasis systematically. Radiocarbon datings were of great importance for clarification of the building's history. Dating series extend from the 10th century BC to the 12th century AD. The temple, of which four building phases could be observed up to now, was used from 9th century BC till the end of the 4th century AD.
Radiocarbon Dating and Balearic Prehistory: Reviewing the Periodization of the Prehistoric Sequence
Authors: Micó Rafael
Published: July 2016

The Balearic Islands are one of the most widely dated regions in Europe, totaling about 800 dates. The aim of this paper is to propose an updated periodization for the prehistory of Majorca and Minorca based on the analysis of a series of absolute dates for over 100 archaeological sites and in combination with a critical assessment of the associated contextual information. Only by means of a solid chronological scheme will we then be able to approach research into the social significance of the vast archaeological record that the islands has to offer and also make reliable comparisons with developments in surrounding regions.
10Be Analyses with a Compact AMS Facility—Are Bef2 Samples the Solution?
Authors: Wacker L , Grajcar M , Ivy-Ochs S , Kubik PW , Suter M
Published: July 2016

The injection of 10BeF- instead of 10BeO- into a compact accelerator mass spectrometry system with a terminal voltage of 0.58 MV was investigated, because BF- molecules are unstable and isobaric interference of 10B with 10Be can thus be significantly reduced. We describe the method we developed to prepare BeF2 samples. 10Be was measured in a segmented gas ionization detector. Separation of 10Be from 10B could be achieved both for ions in the 1+ charge state with an energy of 0.8 MeV and in the 2+ charge state with an energy of 1.4 MeV. The 2+ ions are better separated, whereas the 1+ charge state has a higher transmission. 10Be/9Be ratios (~10-12) in a suite of rock samples were successfully determined for exposure dating in either charge state and compared with measurements made on the 6MV tandem.
Simulation Study for the Separation of Rare Isotopes at the Seoul National University AMS Facility
Authors: Yun C C , Lee C S , Youn M , Kim J C
Published: July 2016

A simulation study for the separation of rare isotopes such as beryllium and aluminum was performed for a new beam line to be attached to the 3MV Tandetron accelerator at the accelerator mass spectrometry (AMS) facility of Seoul National University in Korea. The new beam line will also be used for other scientific applications, namely, ion implantations, Rutherford backscattering, and nuclear astrophysics experiments. It mainly consists of 30° and 100° deflection dipole magnets and drift spaces. A transfer matrix for the beam line was determined by the TRANSPORT code. Simulation of the rare isotope separation was performed by a ray tracing method using the TURTLE code. The simulation results, including the effect of the energy degrader, provide feasibility for the separation of isobars with small mass differences in 10Be-10B and 26Al-26Mg.
Development of a Combustion System for Liquid or Gas Samples
Authors: Park J H , Lee C S
Published: July 2016

While it is customary to use solid samples for measuring the 14C/12C ratio, it is sometimes necessary to handle liquid or gas samples. Motivated by a scientific purpose to count radiocarbon yields in deuterated acetone irradiated with energetic neutrons, we developed a new combustion system to treat liquid or gas samples. In contrast with the typical combustion system using CuO for solid samples, the new combustion system uses high-purity O2 (99.999%) gas. As an initial investigation, we combusted deuterated acetone (acetone-d6, certified 100.0 atm % D) to make CO2 under the ambient O2 pressure. The resulting CO2 gas then went through the reduction process to form graphite for further accelerator mass spectrometry (AMS) measurement.
Chronology of the Beginning of Pottery Manufacture in East Asia
Authors: Keally Charles T , Taniguchi Yasuhiro , Kuzmin Yaroslav V , Shewkomud Igor Y
Published: July 2016

This paper presents an updated radiocarbon chronology of the earliest pottery sites in the Old World. Ceramic production originated in the Late Glacial period in several regions of East Asia—the Japanese Islands, the Russian Far East, and southern China—at approximately the same time, about 13,700–13,300 BP (about 17,200–14,900 cal BP).
Lugovskoe, Western Siberia: A Possible Extra-Arctic Mammoth Refugium at the End of the Late Glacial
Authors: Orlova Lyobov A , Zenin Vasily N , Stuart Anthony J , Higham Thomas F G , Grootes Pieter M , Leshchinsky Sergei V , Kuzmin Yaroslav V , Pavlov Aleksander F , Maschenko Evgeny N
Published: July 2016

Eleven woolly mammoth bone samples from Lugovskoe (central West Siberian Plain, Russia) were radiocarbon dated in 3 laboratories: Institute of Geology, Novosibirsk; Oxford University, Oxford; and Christian Albrechts University, Kiel. Each laboratory used its own protocol for collagen extraction. Parallel dating was carried out on 3 samples in Novosibirsk and Oxford. Two results are in good agreement. However, there is a major discrepancy between 2 dates obtained for the third sample. The dates obtained so far on the Lugovskoe mammoths range from about 18,250 BP to about 10,210 BP. The Lugovskoe results thus far confirm the possibility of woolly mammoth survival south of Arctic Siberia in the Late Glacial after about 12,000 BP, which has important implications for interpreting the process of mammoth extinction. The site has also produced the first reliable traces of human occupation from central Western Siberia at the Late Glacial, including unique direct evidence of mammoth hunting.
Complexity of Soil Organic Matter: AMS 14C Analysis of Soil Lipid Fractions and Individual Compounds
Authors: Rethemeyer Janet , Kramer Christiane , Gleixner Gerd , Wiesenberg Guido L B , Schwark Lorenz , Andersen Nils , Nadeau Marie-J , Grootes Pieter M
Published: July 2016

Radiocarbon measurements of different lipid fractions and individual compounds, isolated from soil samples collected on 2 different agricultural long-term study sites, located in the rural area of Rotthalmünster (Germany) and in the city of Halle/Saale (Germany), were analyzed to obtain information about sources and the stability of soil organic matter (SOM). Different lipid compound classes were isolated by automated solvent extraction and subsequent medium-pressure liquid chromatography. Generally, 14C contents of lipid compound classes from topsoil samples of maize plots at Rotthalmünster are close to the modern atmospheric 14C content. Lower 14C values of aliphatic and aromatic hydrocarbons isolated from neutral lipids suggest a contribution of old carbon to these fractions. In contrast, 14C values of bulk soil (52 pMC) as well as isolated lipid classes from Halle are highly depleted. This can be attributed to a significant contribution of fossil carbon at this site. Extremely low 14C contents of aromatic (7 pMC) and aliphatic hydrocarbons (19 pMC) reflect the admixture of fossil hydrocarbons at the Halle site. Individual phospholipid fatty acids (PLFA), which are used as a proxy for viable microbial biomass, were isolated by preparative capillary gas chromatography (PCGC) from topsoils at Rotthalmünster and Halle. PLFA 14C values are close to atmospheric 14C values and, thus, indicate a clear microbial preference for relatively young SOM. At Rotthalmünster, the 14C concentration of short-chain unsaturated PLFAs is not significantly different from that of the atmosphere, while the saturated PLFAs show a contribution of sub-recent SOM extending over the last decades. At Halle, up to 14% fossil carbon is incorporated in PLFAs n-C17:0 and cy-C18:0, which suggests the use of fossil carbon by soil microorganisms. Moreover, it can be concluded that the 14C age of soil carbon is not indicative of its stability.
Pathways for Escape of Magmatic Carbon Dioxide to Soil Air at Unzen Volcano, SW Japan
Authors: Takahashi Hiroshi A , Kazahaya Kohei , Shinohara Hiroshi , Nakamura Toshio
Published: July 2016

Estimation of the magmatic contribution to soil air at Unzen Volcano, SW Japan, was carried out using carbon isotopes, both 14C and 13C, and a mixing model of isotopic mass balance in order to assess the spatial variation of magmatic influence from the volcano. The advantage of using soil air samples is that a wide range of gas sampling sites can be selected. Magmatic CO2 contributed mostly in the eastern region from Unzen Volcano. The high magmatic contribution to soil air appeared along the Akamatsudani fault zone located southeast of the volcano. Our observations across the fault also showed remarkable peaks of CO2 concentration and δ13C values, suggesting that magmatic fluid comes up along the fracture zone as for the normal fault system of the graben.
A Quality Assurance Protocol for Radiocarbon Dating Laboratories
Authors: Long Austin
Published: July 2016

The purpose of this Quality Assurance (QA) protocol is to summarize guidelines that have been accepted by the majority of directors of radiocarbon dating laboratories throughout the world, and by the International Atomic Energy Agency (IAEA). Laboratories that carefully adhere to this protocol will produce consistently reliable data which will be comparable in accuracy to all other laboratories following this or any other equally rigorous quality assurance program. This statement does not, however, pertain to samples with 14C activities highly sensitive to method or degree of pretreatment, as pretreatment techniques vary among laboratories.
Lithium Contamination in AMS Measurements of 14C
Authors: Loyd D. H. , Vogel J. S. , Trumbore Susan
Published: July 2016

High count rates of lithium ions in an AMS measurement system for 14C were traced to the lithium content in the quartz tubes used in the graphitization of the samples. The lithium contamination was nearly eliminated by the use of borosilicate glass reaction tubes at a lower reaction temperature. The ion beam current and the measurement precision of the isotope ratio were not affected.
Physical Research Laboratory Radiocarbon Date List VI
Authors: Agrawal D. P. , Kusumgar Sheela , Yadava M. G.
Published: July 2016

We present here dates for archaeological and geological samples. The dates are based on τ1/2 = 5568 years, using 1950 as the base year. The modern standard was 95% of activity of NBS oxalic acid.

Samples were pretreated, prepared by methane synthesis and counted in a proportional counter. The detailed procedure has been described earlier (Agrawal, Gupta & Kusumgar 1971). We reported minor changes in previous date lists. Quoted errors are based on counting statistics alone. For samples younger than 10,000 years, the error is 1 standard deviation, and for older samples, 2 standard deviations. The dates are not corrected for 13C fractionation. Samples have been arranged alphabetically according to the name of the site.
Tartu Radiocarbon Dates XII
Authors: Ilves Evald
Published: July 2016

Introduction

This list includes dates of geological samples measured using a single-channel liquid scintillation 14C counter at the Geochemical and Statistical Laboratory, Tartu, Estonia. Our modern standard is made of benzene enriched in 14C, and its activity is checked with NBS oxalic acid standard sample. Dates are given in conventional radiocarbon years, based on the Libby half-life of 5570 ± 30 years. A.D. 1950 is the reference year. Errors refer only to 1σ standard deviation calculated from count rates involved.
Research Center of Radioisotopes at University of Osaka Prefecture Radiocarbon Dates I
Authors: Shibata Setsuko , Kawano Eiko , Nakabayashi Takeshige
Published: July 2016

The radiocarbon dating laboratory has been in operation since 1984 at the Radiation Center of Osaka Prefecture (OR), predecessor of the Research Center of Radioisotopes, University of Osaka Prefecture. We use liquid scintillation counting (LSC), following sample conversion to methanol through combustion and LiAlH4 reduction. This method was developed by Yamada et al. (Yamada, Higashimura and Shidei 1966; Yamada and Kobashigawa 1986). In cooperation with Yamada, we somewhat modified their procedure: 1) sample charcoal is burned at 700° in the presence of CuO needles and Sulfix grains to remove sulfur and halogen compounds produced during the combustion; 2) the combustion is carried out by using N2-O2 mixed gas of minimized O2 content and stopped when a small amount of the charcoal still remains unchanged, because precise investigation of methanol preparation revealed that O2 gas stimulates byproduct formation during LiAlH4 reduction (Shibata et al. 1985; Shibata et al. 1993). Usually, methanol is prepared directly from sample charcoal in a reaction apparatus (“direct method”). When the sample quantity is insufficient, generated CO2 is isolated as CaCO3 and diluted with inactive commercial CaCO3 if necessary (< 40 g of CaCO3 yield). Then CaCO3 is hydrolyzed with HCl to CO2 for methanol preparation in the usual way (“separate method”). We use standard oxalic acid SRM 4990C (HOxII) for determination of modern 14C (Stuiver 1983). The acid is oxidized to CO2 using the wet method of Valastro, Land and Valera (1977) followed by methanol preparation in the same manner as for unknown samples.
A Recent History of 14C, 137Cs, 210Pb, and 241Am Accumulation at Two Irish Peat Bog Sites: an East Versus West Coast Comparison
Authors: Gallagher D , McGee E J , Mitchell P I
Published: July 2016

Data on radiocarbon (14C), 137Cs, 210Pb, and 241Am levels in an ombrotrophic peat sequence from a montane site on the east coast of Ireland are compared with data from a similar sequence at an Atlantic peatland site on the west coast. The 14C profiles from the west and east coasts show a broadly similar pattern. Levels increase from 100 pMC or less in the deepest horizons examined, to peak values at the west and east coast sites of 117 ± 0.6 pMC and 132 ± 0.7 pMC, respectively (corresponding to maximal fallout from nuclear weapons testing around 1964), thereafter diminishing to levels of 110–113 pMC near the surface. Significantly, peak levels at the east coast site are considerably higher than corresponding levels at the west coast site, though both are lower than reported peak values for continental regions. The possibility of significant 14C enrichment at the east coast site due to past discharges from nuclear installations in the UK seems unlikely. The 210Pbex inventory at the east coast site (6500 Bq m−2) is significantly higher than at the west coast (5300 Bq m−2) and is consistent with the difference in rainfall at the two sites. Finally, 137Cs and 241Am inventories at the east coast site also exceed those at the west coast site by similar proportions (east:west ratio of approximately 1:1.2).
Balance and Behavior of Carbon Dioxide at an Urban Forest Inferred from the Isotopic and Meteorological Approaches
Authors: Takahashi Hiroshi Aoki , Hiyama Tetsuya , Konohira Eiichi , Takahashi Atsuhiro , Yoshida Naohiro , Nakamura Toshio
Published: July 2016

Diurnal variations in δ14C, δ13C and the concentration of atmospheric carbon dioxide in an urban forest were measured on 9 February 1999 to discriminate and quantify contributions from different CO2sources. The biogenic CO2concentration remained relatively constant throughout the day. However, anthropogenic CO2concentration fluctuated with the atmospheric CO2concentration, and seemed to be controlled by wind velocity and the amount of exhaust gases from fossil fuel burning. The vertical profiles of anthropogenic, biogenic, and total CO2showed a constant concentration within forest during daytime because of the large vertical CO2influx, strong winds, and neutral atmospheric condition. The biogenic contribution at night decreased from the forest floor upwards with a smooth gradient, while the anthropogenic contribution showed a direct mirror because of the location of respective CO2sources—the vertical gradient of wind velocity and the horizontal CO2supply.
Bomb Carbon as a Tracer of Dietary Carbon Sources in Omnivorous Mammals
Authors: Beavan-Athfield Nancy , Sparks Rodger J
Published: July 2016

We have isolated amino acid groups from modern bone hydrolysates and compared their relative Δ14C value to assess the carbon contribution of diet to the overall radiocarbon signal in bone. We find that both essential and non-essential amino acids may produce widely varying 14C, relative to other amino acid groups in the hydrolysate and to the original whole bone protein. We hypothesize that the 14C variations in non-essential amino acids may be due to metabolic effects that utilize essential amino acid carbon skeletons in the creation of non-essential amino acids.
Radiocarbon AMS Dates for Paleolithic Cave Paintings
Authors: Valladas H , Tisnérat-Laborde N , Cachier H , Arnold M , de Quirós F Bernaldo , Cabrera-Valdés V , Clottes J , Courtin J , Fortea-Pérez J J , Gonzáles-Sainz C , Moure-Romanillo A
Published: July 2016

Advances in radiocarbon dating by accelerator mass spectrometry (AMS) have made it possible to date prehistoric cave paintings by sampling the pigment itself instead of relying on dates derived from miscellaneous prehistoric remains recovered in the vicinity of the paintings. The work at the Laboratoire des Sciences du Climat et de l'Environnement (LSCE) concentrated on prehistoric charcoal cave paintings from southern France and northern Spain. In most caves, pigment samples were collected from several paintings, and in some instances the sample size allowed for multiple independent measurements on the same figure, so that the coherence of the calculated dates could be tested. Before being dated, each specimen was subjected to a thermal treatment preceded by an acid and basic treatment of intensity commensurate with the sample size.

Nine bison drawings from three caves in the Cantabrian region of Spain—two from Covaciella, three from Altamira, and four from El Castillo—were sampled and dated. The 27 dates fell between 13,000 and 14,500 BP, allowing us to attribute the drawings to the Magdalenian period. The 24 dates for 13 drawings in the Cosquer cave indicated two distinct periods of painting activity—one around 28,000 BP and the other around 19,000 BP. The Chauvet cave paintings turned out to be the oldest recorded to date, as five dates fell between 32,000 and 31,000 BP. After discussing the sample preparation protocol in more detail, we will discuss the ages obtained and compare them with other chronological data.
The Cave of Theopetra, Kalambaka: Radiocarbon Evidence for 50,000 Years of Human Presence
Authors: Facorellis Yorgos , Kyparissi-Apostolika Nina , Maniatis Yannis
Published: July 2016

The cave of Theopetra is located on the northeast side of a limestone rock formation, 3 km south of Kalambaka (21°40′46′′E, 39°40′51′′N), in Thessaly, central Greece. It is a unique prehistoric site for Greece, as the Middle and Upper Paleolithic, Mesolithic, and Neolithic periods are present here, bridging the Pleistocene with the Holocene. Several alternations of the climate during the Pleistocene are recognized in its stratigraphy. Among the most striking finds, two human skeletons, one from the Upper Paleolithic period after the Last Glacial Maximum and one from the Mesolithic period, should be emphasized, while in a deep Middle Paleolithic layer, the oldest human footprints, with remains of fire, were uncovered.

During the 13 years of excavation, evidence of human activity suitable for radiocarbon dating was collected, such as charcoal samples from hearths and bones from the two human skeletons. The use of proportional counters for the measurement of14C in combination with the recent improvement of the calibration curve has enabled the production of high-precision reliable ages. Sixty14C-dated samples, originating from 19 pits and from depths ranging from 0.10 m to 4.20 m, have already provided an absolute time framework for the use of the cave. The earliest limit of human presence probably exceeds 48,000 BP and the latest reaches World War II. Within these limits the14C dating of samples from consecutive layers, in combination with the archaeological data, permits the resolution of successive anthropogenic and environmental events.
The Age of Upper Paleolithic Sites in the Middle Dnieper River Basin of Eastern Europe
Authors: Abramova Z A , Grigorieva G V , Zaitseva G I
Published: July 2016

This paper discusses the comparative chronology of Upper Paleolithic sites in the Middle Dnieper River basin, based on archaeological and radiocarbon evidence. Three chronological periods of the development of the Upper Paleolithic are distinguished in this area. According to the data obtained, the third period is similar to the European Magdalenian, yet its economies were different. The base of the subsistence economy for Dnieperian hunters was the procurement of mammoth, while reindeer was the most important for the subsistence of European Magdalenian. The abundance of mammoths and the raw material in the form of mammoth tusks made a deep impact on both the economy and material culture of the hunters in the Dnieper River basin. The 14C dates confirm the chronological subdivision.
Report on the First Stage of the Iron Age Dating Project in Israel: Supporting a Low Chronology
Authors: Sharon Ilan , Gilboa Ayelet , Jull A J Timothy , Boaretto Elisabetta
Published: July 2016

The traditional chronology of ancient Israel in the 11th–9th centuries BCE was constructed mainly by correlating archaeological phenomena with biblical narratives and with Bible-derived chronology. The chronology of Cyprus and Greece, and hence of points further west, are in turn based on that of the Levant. Thus, a newly proposed chronology, about 75–100 yr lower than the conventional one, bears crucial implications not only for biblical history and historiography but also for cultural processes around the Mediterranean. A comprehensive radiocarbon program was initiated to try and resolve this dilemma. It involves several hundreds of measurements from 21 sites in Israel. Creating the extensive databases necessary for the resolution of tight chronological problems typical of historical periods involves issues of quality control, statistical treatment, modeling, and robustness analysis. The results of the first phase of the dating program favor the new, lower chronology.
Hiatus in Prehistoric Chronology of the Cis-Baikal Region, Siberia: Pattern or Artifact?
Authors: Kuzmin Yaroslav V
Published: July 2016

The problem of a hiatus at about 6100–5300 BP (about 4900–4200 cal BC) in the prehistoric chronology of the Cis-Baikal region in Siberia is discussed. Based on a critical evaluation of existing evidence, there was no discontinuity found in the cultural sequence between the Kitoi and Serovo/Glazkovo complexes of the Neolithic, and the proposed “hiatus” may be an artifact based on underestimation of solid data. Conventional 14C dates are presented that were generated in the 1980s to early 2000s for Cis-Baikal prehistoric burial grounds, and were later dated by the accelerator mass spectrometry (AMS).
Investigation into Background Levels of Small Organic Samples at the NERC Radiocarbon Laboratory
Authors: Ertunç Tanya , Xu Sheng , Bryant Charlotte L , Currie Margaret , Freeman Stewart P H T , Maden Colin , Murray Callum
Published: July 2016

Recent progress in preparation/combustion of submilligram organic samples at our laboratories is presented. Routine methods had to be modified/refined to achieve acceptable and consistent procedural blanks for organic samples smaller than 1000 μg C. A description of the process leading to a modified combustion method for smaller organic samples is given in detail. In addition to analyzing different background materials, the influence of different chemical reagents on the overall radiocarbon background level was investigated, such as carbon contamination arising from copper oxide of different purities and from different suppliers. Using the modified combustion method, small amounts of background materials and known-age standard IAEA-C5 were individually combusted to CO2. Below 1000 μg C, organic background levels follow an inverse mass dependency when combusted with the modified method, increasing from 0.13 ± 0.05 pMC up to 1.20 ± 0.04 pMC for 80 μg C. Results for a given carbon mass were lower for combustion of etched Iceland spar calcite mineral, indicating that part of the observed background of bituminous coal was probably introduced by handling the material in atmosphere prior to combustion. Using the modified combustion method, the background-corrected activity of IAEA-C5 agreed to within 2 σ of the consensus value of 23.05 pMC down to a sample mass of 55 μg C.
Methods for High-Precision 14C AMS Measurement of Atmospheric CO2 at LLNL
Authors: Graven Heather D , Guilderson Thomas P , Keeling Ralph F
Published: July 2016

Development of radiocarbon analysis with precision better than 2% has the potential to expand the utility of 14CO2 measurements for carbon cycle investigations as atmospheric gradients currently approach the typical measurement precision of 2–5%. The accelerator mass spectrometer at Lawrence Livermore National Laboratory (LLNL) produces high and stable beam currents that enable efficient acquisition times for large numbers of 14C counts. One million 14C atoms can be detected in approximately 25 min, suggesting that near 1% counting precision is economically feasible at LLNL. The overall uncertainty in measured values is ultimately determined by the variation between measured ratios in several sputtering periods of the same sample and by the reproducibility of replicate samples. Experiments on the collection of 1 million counts on replicate samples of CO2 extracted from a whole air cylinder show a standard deviation of 1.7% in 36 samples measured over several wheels. This precision may be limited by the reproducibility of oxalic acid I standard samples, which is considerably poorer. We outline the procedures for high-precision sample handling and analysis that have enabled reproducibility in the cylinder extraction samples at the <2% level and describe future directions to continue increasing measurement precision at LLNL.
A Chronology of the Pre-Columbian Paracas and Nasca Cultures in South Peru Based on AMS 14C Dating
Authors: Unkel Ingmar , Kromer Bernd , Reindel Markus , Wacker Lukas , Wagner Günther
Published: July 2016

The people of the Paracas and Nasca cultures, the creators of the famous geoglyphs, lived in the desert of the southern coast of Peru between about 800 BC and AD 650. The archaeological chronology of these cultures has been based almost exclusively on a sequence of ceramic styles. The absolute dating of some of the style phases was supported by a few radiocarbon dates (Rowe 1967). Here, we present an absolute chronology of the Paracas and Nasca cultures based on 14C dating of more than 100 organic samples from settlement and tomb relics, as well as on material derived from geoglyph sites in the Nasca/Palpa region (south Peru). The main focus has been on Nasca period settlement centers near Palpa, Los Molinos and La Muña, the Paracas period site of Jauranga, and the Initial period site of Pernil Alto. Most of the 14C samples were dated at the accelerator mass spectrometry (AMS) facility of the ETH Zurich (Switzerland). The targets were produced in the newly built graphitization line at the Heidelberg 14C laboratory (Germany). Clay (adobe) bricks, which are quite a common building material in Peru, were successfully tested to be used for AMS 14C dating of adobe architecture in Peruvian archaeology.
Validating and Improving Archaeological Phasing at St. Mary Spital, London
Authors: Sidell Jane , Thomas Christopher , Bayliss Alex
Published: July 2016

This paper outlines the radiocarbon program applied to the excavation and skeletal assemblage from the cemetery of the medieval Priory and Hospital of St. Mary Spital in London. Problems encountered in dating medieval cemeteries are outlined. The problems were addressed through the application of Bayesian modeling to validate and refine conventional approaches to constructing phases of archaeological activity. It should be noted that this project was solely funded by the developer of the land; such projects rarely undertake even modest programs of 14C dating. We aim to show how the investment of a proportionally small sum, compared to the overall project costs, may reap significant benefits.
Chronology of Key Barrows Belonging to Different Stages of the Scythian Period in Tuva (Arzhan-1 and Arzhan-2 Barrows)
Authors: Zaitseva G I , Chugunov K V , Alekseev A Yu , Dergachev V A , Vasiliev S S , Sementsov A A , Cook G , Scott E M , van der Plicht J , Parzinger H , Nagler A , Jungner H , Sonninen E , Bourova N D
Published: July 2016

This paper focuses on the chronological study of 2 Scythian period monuments that are the key to the chronology of the entire Eurasian Scythian culture. These are the unique monuments of Arzhan-1 and Arzhan-2 in Central Asia (Tuva Republic). The dating of both these monuments began immediately after their discovery, but discussion about their chronological position is still current. Both monuments contained considerable wooden material from their construction suitable for dendrochronology and radiocarbon dating. The first results for the Arzhan-1 barrow were obtained by wiggle-matching in 2004–2005, while the Arzhan-2 barrow was first dated in 2003. It is now possible to compare the chronological position of these barrows using the same methods. As postulated earlier, Arzhan-1 is the oldest Scythian period monument and is dated to the boundary of the 8–9th centuries BC. The position of the Arzhan-2 monument stretches to the middle of the 7th century BC. δ13C values for annual tree rings in logs from both barrows were also determined to gain a better understanding of the climatic conditions at the time of barrow construction.
Chronological and Dietary Aspects of the Human Burials from Ajdovska Cave, Slovenia
Authors: Bonsall C , Horvat M , McSweeney K , Masson M , Higham T F G , Pickard C , Cook G T
Published: July 2016

Ajdovska Jama (The Pagan's Cave) in southeast Slovenia lies within the catchment of the River Sava, a major tributary of the Danube. The site is well known for its Neolithic burials and has been excavated to a high standard on various occasions since 1884. The human remains at the site occurred as distinct clusters of mainly disarticulated bones belonging to at least 31 individuals. Hitherto, dating of the burials has been based on the associated archaeological finds, including a few low-precision radiometric radiocarbon measurements on charred plant material. In the present study, bones from 15 individuals were subsampled for accelerator mass spectrometry (AMS) and stable isotope analyses. These comprised adults and children from 3 of the clusters. The results of the study indicate that the burials all belong to a relatively short time interval, while the stable isotope data indicate a mixed diet based on C3 plant and animal food sources. These interpretations differ somewhat from those of previous researchers. The AMS 14C and stable isotope analyses form part of a wider investigation of dietary and demographic change from the Mesolithic to the Iron Age in the Danube Basin.
Holocene Marine Reservoir Time Series ΔR Values from Cedros Island, Baja California
Authors: Taylor R E , Southon John , Des Lauriers Matthew R
Published: July 2016

ΔR values have been calculated based on offsets in radiocarbon values exhibited in a series of stratigraphically paired charcoal and marine shell values, ranging from about 300 to 10,000 BP, excavated from archaeological sites on Cedros Island, Baja California, Mexico. Based on this data, there appears to be the equivalent of about an 800-yr range in inferred ΔR values (-400 to 400 yr) exhibited in Holocene-age marine shells from this portion of the central Baja California coast.
Controls on the Radiocarbon Reservoir Ages in the Modern Dead Sea Drainage System and in the Last Glacial Lake Lisan
Authors: Belmaker Reuven , Stein Mordechai , Yechieli Yoseph , Lazar Boaz
Published: July 2016

Carbon isotopic and chemical compositions of freshwaters feeding the Dead Sea and the Sea of Galilee (i.e. perennial streams and floods along their stream profiles) were used to constrain the factors that dictate the reservoir ages (RA) of these lakes and the last glacial Lake Lisan. Runoff waters are characterized by high Ca2+, Mg2+, alkalinity, and radiocarbon contents (67–108 pMC), suggesting a major role for 14C atmospheric exchange reactions (carbonate rock dissolution alone will result in lower pMC values). These exchange processes were corroborated by dissolved inorganic carbon (DIC) and δ13C trends throughout the flood profile. During the evolution from rain to incipient runoff, the 14CDIC of the water increases and is accompanied by a DIC increase and δ13CDIC decrease, suggesting an addition of soil CO2, which is characterized by light δ13C and high 14C content. When incipient runoffs evolve to floods, the opposite trends are observed.

It appears that the Sea of Galilee, the Dead Sea, and its last glacial precursor, Lake Lisan, maintained uniform but specific RAs of 0.8 ± 0.1, 2.3 ± 0.1, and 1.6 ± 0.3 kyr, respectively. However, applying the 14C contents of modern Dead Sea water sources to the water mass balance of Lake Lisan reveals that the RA of Lake Lisan is higher than that predicted by the mass balance. This discrepancy may reflect enhanced dissolution of carbonatic dust, changes in the amount of 14C exchanged in Judean Desert floods, or variations in the contribution of brine and saline springs. Furthermore, the small fluctuations in the Lisan RA (1.6 ± 0.3 kyr) may reflect small, short-term changes in the relative contributions of these sources.