bluuebunny/crossref_metadata_2025 huggingface dataset:
230Th-234U and 14C Ages Obtained by Mass Spectrometry on Corals
Authors: Bard Edouard , Arnold Maurice , Fairbanks Richard G. , Hamelin Bruno
Published: July 2016

In 1988, Fairbanks conducted a drilling expedition off the south coast of Barbados to recover submerged corals contemporaneous with the last deglaciation. Core recovery was excellent and >30 different samples were dated by conventional β-counting techniques (Fairbanks 1989). At about the same time, we developed, at Lamont, the thermal ionization mass spectrometry (TIMS) technique to obtain precise U-Th ages (Edwards 1988), and to compare them with the 14C estimates measured on the same samples. A surprising result was that the discrepancy between 14C and U-Th ages increased through time to ca. 3000–3500 yr at ca. 15,000 14C BP (Bard et al. 1990a). Because the three youngest samples yielded U-Th ages in agreement with their calibrated 14C ages, we concluded initially that the TIMS U-Th determinations were not only precise, but also accurate, and that the 14C vs. U-Th data set could be used for a first-order 14C calibration.
δ13C Measurements from the Irish Oak Chronology
Authors: McCormac F. G. , Baillie M. G. L. , Pilcher J. R. , Brown D. M. , Hoper S. T.
Published: July 2016

Measurements of the stable isotope ratio 13C/12C, relative to PDB, were made for fractionation correction purposes on all oak samples used in the Irish oak 14C calibration curve. Stable isotope data have not been published previously. We have collated the stable isotope data from the calibration work, carried out some further measurements to investigate anomalies in the original results, and generated tables of data that include site and tree information pertaining to both stable isotopes and source material for 14C calibration measurements. The data suggest that land-grown trees tend to be isotopically lighter than bog-grown wood, and that the Irish trees used in the calibration exercise tend to be isotopically heavier than those from Scotland and England. Preliminary analysis of the data is given.
Radiocarbon Dating of the Stone and Bronze Age Sites in Primorye (Russian Far East)
Authors: Kuzmin Yaroslav V. , Orlova Lyobov A. , Sulerzhitsky Leopold D. , Jull A. J. T.
Published: July 2016

The first results of radiocarbon dating of the ancient sites in the Russian Far East were published early in the 1960s (Okladnikov 1964). We now have enough data to establish the main features in the 14C chronology of the Stone and Bronze Age cultures in Primorye, one of the archaeologically well-studied regions of the Russian Far East.
Radiocarbon Dating Sites of Northwest Russia and Latvia
Authors: Zaitseva G. I. , Popov S. G.
Published: July 2016

We describe applications of radiocarbon dating used for establishing a chronology of archaeological sites of the Novgorod region at the end of the first millennium ad. We have 14C-dated known-age tree rings from sites in Latvia and ancient Novgorod, northwest Russia, as well as charcoal and wood from Novgorod. Calendar ages of 14C-dated tree rings span the interval, ad 765–999. We used the Groningen calibration program, CAL15 (van der Plicht 1993) to calibrate 14C ages to calendar years. Comparisons between 14C results and archaeological data show good agreement, and enable us to narrow the calendar interval of calibrated 14C determinations.
Mammoth Extinction: Two Continents and Wrangel Island
Authors: Martin Paul S. , Stuart Anthony J.
Published: July 2016

A harvest of 300 radiocarbon dates on extinct elephants (Proboscidea) from the northern parts of the New and Old Worlds has revealed a striking difference. While catastrophic in North America, elephant extinction was gradual in Eurasia (Stuart 1991), where straight-tusked elephants (Palaeoloxodon antiquus) vanished 50 millennia or more before woolly mammoths (Mammuthus primigenius). The range of the woolly mammoths started shrinking before 20 ka ago (Vartanyan et al. 1995). By 12 ka bp, the beasts were very scarce or absent in western Europe. Until the dating of Wrangel Island tusks and teeth (Vartanyan, Garrutt and Sher 1993), mammoths appeared to make their last stand on the Arctic coast of Siberia ca. 10 ka bp. The Wrangel Island find of dwarf mammoths by Sergy Vartanyan, V. E. Garrut and Andrei Sher (1993) stretched the extinction chronology of mammoths another 6 ka, into the time of the pharaohs.
Comparing Long-Term Atmospheric 14C and 3H Records Near Groningen, the Netherlands with Fruholmen, Norway and Izaña, Canary Islands 14C Stations
Authors: Meijer Harro A. J. , van der Plicht Johannes , Gislefoss Jorunn S. , Nydal Reidar
Published: July 2016

We present the results of the 14CO2 atmospheric monitoring station at the Smilde observation station, near Groningen, the Netherlands, a typical continental station. We compared these data, for absolute values and annual variation, with data from Fruholmen, Nordkapp, Norway and Izaña, Tenerife, Canary Islands, which are situated in areas less influenced by fossil-fuel CO2. The 20-yr Smilde record shows much seasonal variation (peak-to-trough variation is ∼30‰ in contrast to ∼12‰ for Fruholmen, and ∼5‰ for Izaña) and a lower overall value due to fossil-fuel consumption, in accordance with findings from similar stations in continental Western Europe. The Fruholmen and Izaña data show fairly equal mean Δ14C levels, but differ in seasonal amplitude. This difference could be due partly to the elevation difference between the stations. The Izaña station also has a slow exchange with the ground-level air because of an inversion layer. It is speculative whether annual injection of 14C from the stratosphere also plays a role. We give the Groningen long record of tritium in precipitation, showing profound seasonality.
Comparing 14C Histograms: An Approach Based on Approximate Randomization Techniques
Authors: Dye Tom
Published: July 2016

An approximate randomization technique for comparing 14C histograms is described and illustrated with an example from Hawai'i. The technique determines intervals of significant difference in the histograms, rather than providing a single number summary.
Radiocarbon in Tropospheric CO2 and Organic Materials from Selected Northern Hemisphere Sites
Authors: Druffel Ellen R. M. , Griffin Sheila
Published: July 2016

Radiocarbon was measured in atmospheric CO2 from La Jolla, California and in living organic materials from six sites in the northern hemisphere. Atmospheric CO2 ∆14C values from La Jolla agreed with those previously published records from China Lake, California (Berger et al. 1987) and Vermunt, Austria (Levin et al. 1985). ∆14C values of fruit and grain samples that grew during 1980 agreed with the atmospheric CO2 ∆14C measurements. Most of the ∆14C results of fruit and corn samples stored since the 1940s agreed with tree-ring ∆14C values for the same time period. In general, agreement was found between the atmospheric CO2 or tree-ring ∆14C records available for the Northern Hemisphere and the ∆14C signatures of rapidly exchanging organic matter pools examined in this study. Exceptions were the ∆14C values of carbonate from egg shells and that of organic carbon from egg insides, which demonstrate that bicarbonate and organic carbon within the egg follow different biochemical pathways.
On Cosmic-Ray Exposure Ages of Terrestrial Rocks: A Suggestion
Authors: Lal Devendra
Published: July 2016

An important recent development in the field of geomorphology has been the application ofin-situcosmic-ray-produced nuclides to obtain modelerosion ratesandsurface exposure ages.These concepts emerged some four decades ago in studies of cosmogenic nuclides in meteorites, but cannot generally be used analogously for terrestrial rocks. The differences in the two cases are outlined. For the case ofsteady-state erosional histories, the terrestrialsurface exposure agesdepend on the half-life of the radionuclide studied. A suggestion is made for presenting thesurface exposure ages, which allows a clear definition of the meaning of the estimated exposure ages. In the case of adiscrete exposure history, the meaning of “exposure age”—which should more appropriately be called “event age”—is however quite unambiguous.
Palynological and Sedimentological Evidence for a Radiocarbon Chronology of Environmental Change and Polynesian Deforestation from Lake Taumatawhana, Northland, New Zealand
Authors: Elliot M. B. , Striewski B. , Flenley J. R. , Sutton D. G.
Published: July 2016

We present pollen diagrams and sedimentological analyses from a lake site within an extensive dune system on the Aupouri Peninsula, Northland. Five thousand years ago, a regional Agathis australis–podocarp-broadleaf forest dominated the vegetation, which manifested an increasing preponderance of conifer species. Climate was cooler and drier than at present. From ca. 3400 bp, warmth-loving species such as A. australis and drought-intolerant species, Dacrydium cupressinum and Ascarina lucida, became common, implying a warm and moist climate. The pollen record also suggests a windier climate. The most significant event in the record, however, occurred after ca. 900 bp (800 cal bp) when anthropogenic deforestation commenced. A dramatic decline in forest taxa followed, accompanied by the establishment of a Pteridium–esculentum-dominated community. Fire almost certainly caused this, evidenced by a dramatic increase of charcoal. Sedimentological evidence for this site indicates a relatively stable environment before humans arrived and an increasingly unstable environment with frequent erosional events after human contact.
Spatial and Temporal Dependence of the 13C and 14C Isotopes of Wine Ethanols
Authors: Martin Gérard J. , Thibault Jean-Noël
Published: July 2016

More than 1000 authentic samples of ethanols were extracted by quantitative distillation from vintage wines and brandies prepared from grapes harvested in well-defined regions and years. The 13C contents of these ethanols were determined by isotope ratio mass spectrometry (IRMS) and the 14C activity of most of these samples was determined by liquid scintillation counting (LSC). We show that the 13C content of a C3 plant such as grape vine, which strongly depends on water availability, spans nearly a 10% range worldwide. The efficiency of the 14C content of grape ethanols as a tracer of the CO2 turnover after the peak of the nuclear test in the 1960s is also discussed in terms of geographical effects. Finally, the necessity of a multi-isotopic approach, including 13C and 14C isotopes, for detecting sophisticated adulterations is illustrated in the case of wines and brandies.
Estimation of Slow- and Fast-Cycling Soil Organic Carbon Pools from 6N HCl Hydrolysis
Authors: Leavitt S. W. , Follett R. F. , Paul E. A.
Published: July 2016

Acid hydrolysis is used to fractionate the soil organic carbon pool into relatively slow- and fast-cycling compartments on soils from Arizona, the Great Plains states and Michigan collected for carbon isotope tracer studies related to soil carbon sequestration, for studies of shifts in C3/C4 vegetation, and for “pre-bomb” soil-carbon inventories. Prior to hydrolysis, soil samples are first treated with cold 0.5–1N HCl to remove soil carbonates if necessary. Samples are then dispersed in a concentrated NaCl solution (ρ≍1.2 g cm-3) and floated plant fragments are skimmed off the surface. After rinsing and drying, all remaining recognizable plant fragments are picked from the soil under 20x magnification. Plant-free soils, and hot, 6N HCl acid-hydrolysis residue and hydrolyzate fractions are analyzed for carbon content, δ13C and 14C age, and the carbon distribution is verified within 1–2% by stable-carbon isotope mass balance. On average, the recalcitrant residue fraction is 1800 yr older and 2.6% more 13C-depleted than total soil organic carbon. A test of hydrolysis with fresh plant fragments produced as much as 71–76% in the acid-hydrolysis residue pool. Thus, if plant fragments are not largely removed prior to hydrolysis, the residue fraction may date much younger than it actually is.
14C Measurements of Soil Organic Matter, Soil Co2 and Dissolved Organic Carbon (1987–1992)
Authors: Tegen Ina , Dörr Helmut
Published: July 2016

For several undisturbed sites in Germany, 14C data are reported for soil organic matter (SOM) (4 sites), soil CO2 (10 sites) and dissolved organic carbon (DOC) (1 site). With the assumption of a fast degradable component (lifetime ca. 1 yr) and a slow degradable component (lifetime ca. 100 yr), a range between 0.6 and 1.6 mm yr-1 has been determined for the downward migration rates of soil organic carbon at the sampling sites from the soil 14C data. The soil CO2 measurements show that in deciduous forests the fast degradable component is ca. 60% and the slow degradable component is ca. 40% of the SOM. In coniferous forests this ratio is reversed. The 14C results for DOC could not be explained with the assumption of a first-order decay process. The removal of soil organic carbon by DOC is of minor importance for the estimation of carbon budgets for the investigated site.
The Influence of Pretreatment on Humic Acid Yield and 14C Age of Carex Peat
Authors: Cook G. T. , Dugmore A. J. , Shore J. S.
Published: July 2016

The object of the study was to assess the effects of a range of pretreatment/extraction schemes on the yields of humic acid and humin obtained from peat and the subsequent radiocarbon ages. We analyzed peat from Flókadalur in northern Iceland, collecting material from a profile containing seven visible tephra horizons in the upper 3 m, whose form and extent indicated little disturbance to the section over the last 4000 yr. The results of a range of pretreatments demonstrated that time rather than the strength of alkali is the more important factor governing the extraction of humic acid. An increase in alkali molarity did not correspond to any systematic increase in yield, whereas an increase in time did, implying that the extraction is kinetically controlled. We found no evidence of variability in 14C age due to pretreatment scheme or between different geochemical fractions of the peat. Further implications from this study are that bog stability and ecological simplicity produce a favorable environment for 14C dating.
Preparation of Inorganic and Organic Carbon for 14C Analysis from a Single Marine Sample
Authors: Griffin Sheila , Druffel Ellen R. M.
Published: July 2016

We have developed a technique using a single apparatus to recover the inorganic and organic carbon from a small (few milligrams) aliquot of dried marine material for radiocarbon analysis. The main advantages of using a single apparatus are: 1) less sample is required, 2) decreased handling reduces contamination, and 3) less time and materials are used. Blank values of ∼5 μg and 19–44 μg are obtained for the inorganic and organic carbon extractions, respectively. δ14C results from sinking particulate organic and inorganic carbon are presented for samples collected in deep-sea sediment traps deployed for 10–30 day periods at 650 and 100 m above bottom (mab) in the northeast Pacific Ocean.
Microscale AMS 14C Measurement at NOSAMS
Authors: Pearson Ann , Mcnichol Ann P. , Schneider Robert J. , Von Reden Karl F. , Zheng Yan
Published: July 2016

Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO2 are reduced to graphite over cobalt catalyst at an optimal temperature of 605°. Measured 14C/12C ratios of the resulting targets are affected by machine-induced isotopic fractionation, which appears directly related to the decrease in ion current generated by the smaller sample sizes. It is possible to compensate effectively for this fractionation by measuring samples relative to small standards of identical size. Examination of the various potential sources of background 14C contamination indicates that the sample combustion process is the largest contributor, adding ca. 1 μg of carbon with a less-than-modern 14C concentration.
Target Preparation for Continuous Flow Accelerator Mass Spectrometry
Authors: Schneider Robert J. , Hayes J. M. , Von Reden Karl F. , McNichol Ann P. , Eglinton T. J. , Wills J. S. C.
Published: July 2016

For very small samples, it is difficult to prepare graphitic targets that will yield a useful and steady sputtered ion beam. Working with materials separated by preparative capillary gas chromatography, we have succeeded with amounts as small as 20 μg C. This seems to be a practical limit, as it involves 1) multiple chromatographic runs with trapping of effluent fractions, 2) recovery and combustion of the fractions, 3) graphitization and 4) compression of the resultant graphite/cobalt matrix into a good sputter target. Through such slow and intricate work, radiocarbon ages of lignin derivatives and hydrocarbons from coastal sediments have been determined. If this could be accomplished as an “online” measurement by flowing the analytes directly into a microwave gas ion source, with a carrier gas, then the number of processing steps could be minimized. Such a system would be useful not just for chromatographic effluents, but for any gaseous material, such as CO2 produced from carbonates. We describe tests using such an ion source.
Gas Counting System for 14C Dating of Small Samples in the Kraków Laboratory
Authors: Gorczyca Zibigniew , Jeleń Kazimierz , Kuc Tadeusz
Published: July 2016

The application of traditional gas or liquid scintillation counting (LSC) is necessary for assessing radionuclide activity in countries without operating accelerator mass spectrometry (AMS) facilities. A simple and relatively inexpensive system of mini gas counters for measurement of radiocarbon in archaeological and environmental samples has been set up recently in the Kraków laboratory (Department of Environmental Physics, University of Mining and Metallurgy). The system is composed of a gas purification and counter filling line, three identical 15-mL copper/quartz counters, active and passive shielding, and an electronic unit with data acquisition. One counter measures 22 mg of carbon as CO2 with efficiency >95% at a background reduced to 0.044 cpm by a NaJ(Tl) guard counter and lead shield. The detection limit (1 σ) for a two-week measurement of 48 mL of CO2 is 0.52 pMC. The corresponding counting error of a 100 pMC environmental sample is 1.3 pMC for 22 mgC (one counter) and 0.75 pMC for 66 mgC (three counters filled with the same sample).
The New Nagoya Radiocarbon Laboratory
Authors: Muraki Yasushi , Kocharov Grant , Nishiyama Tooru , Naruse Yukiko , Murata Takuya , Masuda Kimiaki , Arslanov Kh. A.
Published: July 2016

A liquid scintillation counting apparatus that enables highly accurate measurements of 14C has been constructed at the Solar-Terrestrial Environment Laboratory, Nagoya University. The main aim of the project is high precision year-by-year measurements of the 14C content in tree rings of an old cedar tree from Yaku Island, Japan. We present the results of 14C measurements on tree rings from the Agematsu region for recent decades to confirm the validity of the system.
A Remotely Operated, Field-Deployable Tritium Analysis System for Surface and Ground Water Measurement
Authors: Noakes J. E. , Spaulding J. D. , Neary M. P.
Published: July 2016

We have worked in collaboration with the Westinghouse Savannah River Company and Packard Instrument Company to develop a prototype instrument for remote, near real-time, in situ analysis of environmental levels of tritium in surface and ground water samples. The unit consists of a Packard Radiomatic™ 525TR liquid scintillation counter that has been modified to achieve lower detection levels through background reduction using Packard's After-Pulse Burst Discrimination electronics and an auxiliary Bi4Ge3O12 scintillation detector guard. The system is fully programmable to enable remote calibration, sample collection, sample analysis, reconfiguration of operational mode and interrogation for analytical results.
The Erlangen AMS Facility and its Applications in 14C Sediment and Bone Dating
Authors: Kretschmer W. , Anton G. , Benz M. , Blasche S. , Erler G. , Finckh E. , Fischer L. , Kerscher H. , Kotva A. , Klein M. , Leigart M. , Morgenroth G. , Küster H.
Published: July 2016

We report here on the radiocarbon dating of sediment samples from Bavaria using the Erlangen accelerator mass spectrometry facility. The absolute time calibration of different sediment profiles, together with pollen analyses, should establish a better chronology of climate and vegetation during Holocene in Bavaria. For an enhanced reliability of sediment dating, we measured different fractions such as bulk sediments, pollen grains, macrofossils and humic acids. For these fraction, we describe the separation methods and conversion to sputter targets. Furthermore, we discuss the sample preparation for the dating of bones and present some results.
14C AMS Measurements of <100 μG Samples with a High-Current System
Authors: Von Reden Karl F. , McNichol Ann P. , Pearson Ann , Schneider Robert J.
Published: July 2016

The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 μg C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One of the main factors affecting the AMS results is the dependence of a number of the beam optics parameters on the extracted ion beam current. The extracted currents range from 0.5 to 10 μA of 12C− for the sample sizes given above. We here discuss the setup of the AMS system and methods for reliable small-sample measurements and give the AMS-related limits to sample size and the measurement uncertainties.
New 14C Reference Materials with Activities of 15 and 50 pMC
Authors: Clercq Martijn Le , Van Der Plicht Johannes , Gröning Manfred
Published: July 2016

Two new 14C reference materials have been developed for international use, filling a gap in the present C1–C6 series available from the IAEA. By mixing a modern and a synthetic substance, 150 kg of C7 (ca. 50 pMC activity) and C8 (ca. 15 pMC activity), respectively, were obtained.
The Pursuit of Isotopic and Molecular Fire Tracers in the Polar Atmosphere and Cryosphere
Authors: Currie L. A. , Dibb J. E. , Klouda G. A. , Benner B. A. , Conny J. M. , Biegalski S. R. , Klinedinst D. B. , Cahoon D. R. , Hsu N. C.
Published: July 2016

We present an overview of recent multidisciplinary, multi-institutional efforts to identify and date major sources of combustion aerosol in the current and paleoatmospheres. The work was stimulated, in part, by an atmospheric particle “sample of opportunity” collected at Summit, Greenland in August 1994, that bore the 14C imprint of biomass burning. During the summer field seasons of 1995 and 1996, we collected air filter, surface snow and snowpit samples to investigate chemical and isotopic evidence of combustion particles that had been transported from distant fires. Among the chemical tracers employed for source identification are organic acids, potassium and ammonium ions, and elemental and organic components of carbonaceous particles. Ion chromatography, performed by members of the Climate Change Research Center (University of New Hampshire), has been especially valuable in indicating periods at Summit that were likely to have been affected by the long range transport of biomass burning aerosol. Univariate and multivariate patterns of the ion concentrations in the snow and ice pinpointed surface and snowpit samples for the direct analysis of particulate (soot) carbon and carbon isotopes. The research at NIST is focusing on graphitic and polycyclic aromatic carbon, which serve as almost certain indicators of fire, and measurements of carbon isotopes, especially 14C, to distinguish fossil and biomass combustion sources.

Complementing the chemical and isotopic record, are direct “visual” (satellite imagery) records and less direct backtrajectory records, to indicate geographic source regions and transport paths. In this paper we illustrate the unique way in which the synthesis of the chemical, isotopic, satellite and trajectory data enhances our ability to develop the recent history of the formation and transport of soot deposited in the polar snow and ice.
14C Cycle in the Hot Zone Around Chernobyl
Authors: Kovaliukh Nikolai N. , Skripkin Vadim V. , Van Der Plicht Johannes
Published: July 2016

Radiocarbon from the Chernobyl accident was released mainly in two forms: fine dispersed reactor graphite, and carbon dioxide from burning graphite. The CO2 was partly assimilated by annual and perennial vegetation. Reactor graphite dispersed over a wide territory was taken up biochemically by micromicetes, transforming non-organic carbon of the reactor graphite into organic matter. Organic matter of micromicetes is the main nutrition product for soil organisms such as bacteria, worms, larvae of insects, small beetles, etc. The following relatively independent trophic chains are considered: 1. carbon dioxide → leaves, grass → insects; 2. graphite → micromicetes, protozoa, insects. The 14C content in beetles of different species sampled in the 30-km hot zone of the Chernobyl accident site in 1986–1988 agrees well with the contamination levels of insect habitats as well as with their biology.
Extension of the 14C Calibration Curve to ca. 40,000 Cal BC by Synchronizing Greenland 180/16O Ice Core Records and North Atlantic Foraminifera Profiles: A Comparison with U/Th Coral Data
Authors: Jöris Olaf , Weninger Bernhard
Published: July 2016

For a better understanding of pre-Holocene cultural history, archaeologists are in need of an absolute time scale that can be confirmed and duplicated by different dating methods. Proxy data available from archaeological sites do not, in themselves, allow much reflection on absolute age. Even when founded on supporting radiocarbon data, Paleolithic chronologies that are beyond the actual limits of 14C calibration still remain relative ones, and thus are often quite tentative. Lacking the possibility of calibration for the Paleolithic, archaeologists often attempt to correlate their data with different time scales from different archives that are thought to be absolute or calendric. The main result of this paper is that the GISP2 and U/Th chronologies duplicate each other over their entire range of data overlap, while other time scales (i.e., GRIP, most varve sites) differ significantly. The context-derived 14C calibration curve provides a large potential to correlate the various climate archives as recorded in ice cores and deep ocean drillings with terrestrial sequences.
The Sharp Rise of Δ14Cca. 800 cal BC: Possible Causes, Related Climatic Teleconnections and the Impact on Human Environments
Authors: Van Geel Bas , Van Der Plicht Johannes , Kilian M. R. , Klaver E. R. , Kouwenberg J. H. M. , Renssen H. , Reynaud-Farrera I. , Waterbolk H. T.
Published: July 2016

In this study we report on accelerator mass spectrometry (AMS) wiggle-match dating of selected macrofossils from organic depositsca. 800 cal bc (ca. 2650 bp). Based on paleological, archaeological and geological evidence, we found that the sharp rise of atmospheric14C between 850 and 760 cal bc corresponds to the following related phenomena:

1.

In European raised bog deposits, the changing spectrum of peat forming mosses and a sharp decline in decomposition of the peat indicate a sudden change from relatively dry and warm to cool, moist climatic conditions.

2.

As a consequence of climate change, there was a fast and considerable rise of the groundwater table so that peat growth started in areas that were already marginal from a hydrological point of view.

3.

The rise of the groundwater table in low-lying areas of the Netherlands resulted in the abandonment of settlement sites.

4.

The contemporaneous earliest human colonization of newly emerged salt marshes in the northern Netherlands (after loss of cultivated land) may have been related to thermal contraction of ocean water, causing a temporary stagnation in the relative sea-level rise.

Furthermore, there is evidence for synchronous climatic change in Europe and on other continents (climatic teleconnections on both hemispheres)ca. 2650 bp. We discuss reduced solar activity and the related increase of cosmic rays as a cause for the observed climatological phenomena and the contemporaneous rise in the14C-content of the atmosphere. Cosmic rays may have been a factor in the formation of clouds and precipitation, and in that way changes in solar wind were amplified and the effects induced abrupt climate change.
Using the Bayesian Method to Study the Precision of Dating by Wiggle-Matching
Authors: Goslar Tomasz , Mądry Wiesław
Published: July 2016

The “wiggle-matching” technique has been widely used for the absolute dating of a series of radiocarbon-dated samples connected in one floating chronology. This is done by calculations of SS statistics (the mean-square distance of 14C ages of samples from the calibration curve) calculated for any assumed calendar age of the floating chronology. In the standard procedure the confidence intervals of true calendar age are derived from the width of the SS minimum, using the critical values of the chi-square distribution. This, however, seems oversimplified. Another approach is an extension of the Bayesian algorithm for calibration of single 14C dates. Here, we describe in detail the Bayesian procedure and discuss its advantages compared to the SS minimization method. Our calculations show that for given errors of 14C measurements, precision of dating the series is related to the shape of the SS curve around its minimum, rather than to the absolute value of SSmin. In some cases, dating precision may be improved more efficiently by extending the time span covered by the series rather than by improving the precision of the 14C measurements. The application of the Bayesian method enabled us to delimit the age of the floating varve chronology from the sediments of Lake Gościąż with distinctly better accuracy than was previously reported using the SS curve alone.
14C Dating of a Neolithic Field System at Céide Fields, County Mayo, Ireland
Authors: Caulfield Seamas , O'Donnell R. G. , Mitchell P. I.
Published: July 2016

Céide Fields is a 12 km2 Neolithic field system in North Mayo in the west of Ireland. The fields, enclosed by an integrated system of stone walls, have been preserved intact by a cover of blanket bog that is >4 m deep in places. At many locations within this blanket bog the stumps of ancient pines (Pinus sylvestris) are found in situ. The pine roots in most cases are either on the surface of the mineral soil under the peat or at an intermediate level in the peat itself. The age of the trees in the bog overlying Céide Fields is therefore of great significance for the dating of the fields, as the trees must be younger than the bog in which they are growing, which in turn must be younger than the field system beneath it. We present here the dates (N = 15) for pine trees from the bogs overlying Céide Fields and the dates (N = 29) of pine trees from other areas of the North Mayo blanket bog. We compare these pine dates with published dates of peat associated with a major pollen analytical study from within the fields and with published dates for bog pine from Scotland. The results of the study suggest that the dates for the construction and period of use of Céide Fields and other Neolithic pre-bog field systems in North Mayo are older than anticipated and that the date for initiation of blanket bog in many parts of North Mayo is also older than previously estimated. Further, the range of dates of the pine stumps indicates a synchronic event contemporary with a similar phenomenon observed in Scotland.
14C Chronology of Stone Age Cultures in the Russian Far East
Authors: Kuzmin Yaroslav V. , Jull A. J. T. , Orlova Lyobov A. , Sulerzhitsky Leopold D.
Published: July 2016

Ca. 150 unequivocal 14C dates from the prehistoric cultures in the Russian Far East can be used to elucidate chrono-cultural boundaries in that region. Microblade technology started as early as ca. 20,000 bp, and continued to exist in the middle Amur River basin until ca. 10,500 bp, and in Primorye until ca. 7800 bp. The emergence of pottery-making in the lower Amur River basin goes back to ca. 13,300 bp. The transition from Upper Paleolithic to Neolithic took place during the time interval 13,300–7800 bp and pottery was widely spread in the Russian Far East by ca. 6700–8400 bp. The first evidence of shellfish collection is estimated to ca. 6400 bp at Peter the Great Gulf coast, Sea of Japan. The beginning of agriculture in Primorye, based on finding of both millet seeds (Setaria italica L.) and pollen of cultivated cereals (Cerealia), is 14C-dated to ca. 4200–3700 bp (ca. 1980–2900 cal BC). The Neolithic/Early Iron Age boundary was estimated at ca. 3100–3300 bp (1400–1600 cal BC) in the mainland Russian Far East, and to ca. 1800–2300 bp (400 cal BC–200 cal ad) on the Sakhalin and southern Kuril Islands.
Wadi Shaw 82/52: 14C Dates from a Peridynastic Site in Northwest Sudan, Supporting the Egyptian Historical Chronology
Authors: Lange Mathias
Published: July 2016

In the framework of the interdisciplinary project “Settlement History of the Eastern Sahara” at the Universität zu Köln, a large number of sites were excavated during the 1980s in northern Sudan, where the Laqiya-region with the Wadi Shaw and Wadi Sahal was one of the main research areas. About 150 sites have been surveyed and partly excavated. One of these sites, Wadi Shaw 82/52, yielded sherds of a Maidum bowl, which is dateable to the Egyptian IVth and Vth Dynasty. This site was dated by four radiocarbon dates. The dates are compared with the historical chronology of Egypt for the IVth and Vth Dynasty, and are shown to be in good agreement.
Ground Sloth Extinction and Human Occupation at Gruta Del Indio, Argentina
Authors: Long Austin , Martin Paul S. , Lagiglia Humberto A.
Published: July 2016

A new set of radiocarbon dates from a rockshelter in Mendoza, Argentina addresses the question of the temporal overlap between the presence of an unidentified extinct ground sloth (cf., Mylodontidae) and evidence of human activity. Dung balls on the cave floor, evidently deposited by sloth, are overlain by charcoal, apparently of cultural origin. 14C dates, mostly on charcoal and dung from this shelter, calibrated using recently published curves, as well as the stratigraphy of the deposits from which the samples were collected, suggest that any co-occurrence of humans and ground sloths in this region was brief. In contrast, the single date on mylodon dermal ossicles from this shelter suggests significant time overlap. Replication of this date as well as obtaining new high-precision 14C analyses from this site will be the next priority.
14C Dating Ancient Japanese Documents
Authors: Oda Hirotaka , Nakamura Toshio , Furukawa Michiaki
Published: July 2016

We measured radiocarbon ages of 11 pieces of ancient Japanese documents by accelerator mass spectrometry (AMS). The purpose of this study is to compare the relationship between the calibrated 14C age and the historical age of Japanese paper samples. Calibrated ages of nine pieces agree with their historical ages, indicating that Japanese ancient documents can be used for 14C dating in the recent historic period. On the other hand, the 14C age of paper that was used for reinforcement of a sutra is ca. 300 yr older than the historical age of the sutra. This shows that the sutra was repaired with old paper.
14C Dating of Late Pleistocene–Holocene Events on Kunashir Island, Kuril Islands
Authors: Bazarova V. B. , Razjigaeva N. G. , Grebennikova T. A. , Ganzey L. A. , Mokhova L. M. , Korotky A. M. , Sulerzhitsky L. D.
Published: July 2016

Kunashir Island is a very important site for paleoenvironmental reconstructions. Until recently, very little information on Quaternary deposits was available. We studied the environmental evolution of this oceanic island under the influence of geomorphological processes, volcanism and strong marine currents. This paper presents new data that allow a detailed reconstruction of the environmental development of Kunashir Island during the Late Pleistocene–Holocene, based on ca. 80 radiocarbon dates and diatom, pollen and sedimentological data. The vegetation development reflects climate changes and warm/cold current migrations.
14C Ages of Terrestrial Macrofossils from Lago Grande Di Monticchio (Italy)
Authors: Hajdas Irka , Bonani Georges , Zolitschka Bernd , Brauer Achim , Negendank Jörg
Published: July 2016

Lago Grande di Monticchio (Italy) contains long sedimentary records of >75 ka (Zolitschka and Negendank 1996). In a joint European project (Creer and Thouveny 1996), vegetation history and climatic changes for this part of the Mediterranean have been reconstructed (Watts, Allen and Huntley 1996; Watts et al. 1996). In addition to the time scale based on annual laminations and sedimentation rate, tephra layers and pollen spectra, radiocarbon dating was applied for the last 40 ka. Previous studies have shown that the age of bulk sediment from Lago Grande di Monticchio, which is a maar lake at the flanks of Mt. Vulture, was influenced by “dead carbon” of volcanic origin dissolved in the lake water. Thus, 14C dating of the record is problematic and must be limited to dating macrofossils of terrestrial origin.

From a set of sediment samples, macrofossils were selected and dated using accelerator mass spectrometry (AMS). A 14C time scale based on seven data points between 9000 and 24,000 bp is compared with other dating of the record based on varve counting and tephrochronology (Zolitschka 1996).
Reconstruction of Microenvironmental Changes in the Kopasz Hill Loess Area at Tokaj (Hungary) Between 15 and 70 ka BP
Authors: Sümegi Pál , Hertelendi Ede
Published: July 2016

We collected 11 Kopasz Hill loess profiles for paleoecological and geochronological analysis. The loess accumulation and development formed during the last (Weichselian) glacial period between 70 and 15 ka bp. We found that the majority of the loess profiles were composed of three typical loess strata and two well-developed paleosol horizons. Based on vertebrate remains, the lowest loess layer formed between 70–50 ka bp, during the first cool and dry climatic phase of the last glacial period, when forest steppe vegetation dominated in the Kopasz Hill area. On the surface of the lowermost layer, a paleosol developed between 50 and 40 ka bp as an indication of a more humid and warmer climatic phase. This paleosol layer was buried by a new loess layer that developed between 40 and 32 ka bp. The upper paleosol horizon developed between 32 and 26 ka bp. Molluscs preferring a mild climate were found in this layer, suggesting that this phase was wet and relatively temperate. A number of fired macrocharcoal remains can be found on the top of this paleosol layer. Charcoal samples from nine sites were dated by radiocarbon analyses. These results reflect the presence of a charcoal-rich horizon that developed 28–26 ka bp. Ca. 26 ka bp, loess formation resumed. We analyzed 14 samples from 6 sites by the 14C method. Based on 14C data, the uppermost part of loess profiles developed between 26 and 15 ka bp.
14C Studies of Natural Ice
Authors: Wilson A. T.
Published: July 2016

There are many kinds of natural ice found on our planet. These include glacier ice, ice sheets, cave ice, massive ground ice, ice-wedge ice and permafrost ice. The problems associated with the recovery and dating of the CO2 and other gases contained in these kinds of ice is reviewed. New data are presented on various kinds of natural ice. How this kind of data can be used to help determine the origin and history of natural ice samples is discussed, along with the kind of paleoclimatic information that might be obtained from natural ice samples.
14C Dating and Stable Carbon Isotopes of Soil Organic Matter in Forest–Savanna Boundary Areas in the Southern Brazilian Amazon Region
Authors: Pessenda L. C. R. , Gouveia S. E. M. , Aravena Ramon , Gomes B. M. , Boulet Rene , Ribeiro A. S.
Published: July 2016

This study, which was carried out in the southern Brazilian Amazon region (Rondônia state and Humaitá, Southern Amazon state), presents and discusses the significance of carbon isotope data measured in soil profiles collected across natural boundaries of forest to savanna vegetation. The main objective of this study was to evaluate the expansion-regression dynamics of these vegetation units in relation to climate changes during the Holocene.14C data from charcoal, soil organic matter (SOM) and its component humin fraction indicate that the organic matter in the studied soils is essentially Holocene in origin.13C data indicate that C3type plants were the dominant vegetation at all study areas in the early Holocene, and during the entire Holocene, in the forest sites of Central Rondônia state and in the forest site 50 km from the city of Humaitá.13C data also indicate that C4plants have influenced significantly the vegetation at the transitional forest and the Cerrado (wooded savanna) sites of Southern Rondônia state and the forest ecosystem located 20 km from the Humaitá city. These typical C4type isotopic signatures probably reflect a drier climate during the mid-Holocene. The13C records representing probably the last 3000 yr show an expansion of the forest, due to a climatic improvement, in areas previously occupied by savanna vegetation. These results and other published data for the Amazon region indicate that the areas representing today's forest-savanna boundaries have been determined by significant vegetation changes during the Holocene. The boundary between forest and savanna vegetation seems to be quite sensitive to climatic change and should be the focus of more extensive research to correlate climate and past vegetation dynamics in the Amazon region.
Soil Organic14C Dynamics: Effects of Pasture Installation on Arable Land
Authors: Römkens Paul F. A. M. , Hassink Jan , Plicht Johannes Van der
Published: July 2016

In a study addressing composition and recovery of soil carbon following pasture installation on arable land, radiocarbon isotope ratios were measured in size- and density-separated soil organic matter (SOM) fractions in a pasture and maize plot. The average soil carbon age increased with depth from 444 yr in the 0–30-cm layer to 2456 yr in the 60–80-cm layer in the pasture soils, and from 42 to 1625 yr in the maize-cultivated soil. Weight fractionation of the macro-organic matter (size >150 μm) in a light (density <1.17 g cm-3) intermediate (1.17 g cm-3< density < 1.37 g cm-3), and heavy fraction (density >1.37 g cm-3) resulted in markedly different ages for different fractions with ages increasing from 2 yr in the light fraction to >3000 yr in the heavy fractions.13C and14C (accelerator mass spectrometry (AMS)) isotope ratios in the <20 μm fraction in the 60–80-cm layer indicated that vertical displacement of colloidal organic material occurred during maize cropping. The physical fractionation method, in combination with natural level13C and14C analysis, resulted in a better insight in carbon dynamics that occur after the conversion of arable land to pasture.
A High-Resolution Radiocarbon Calibration Between 11,700 and 12,400 Calendar Years Bp Derived from 230Th Ages of Corals from Espiritu Santo Island, Vanuatu
Authors: Burr G. S. , Beck J. Warren , Taylor F. W. , Récy Jacques , Edwards R. Lawrence , Cabioch Guy , Corrège Thierry , Donahue D. J. , O'malley J. M.
Published: July 2016

This paper presents radiocarbon results from a single Diploastrea heliopora coral from Vanuatu that lived during the Younger Dryas climatic episode, between ca. 11,700 and 12,400 calendar yr bp. The specimen has been independently dated with multiple 230Th measurements to permit calibration of the 14C time scale. Growth bands in the coral were used to identify individual years of growth. 14C measurements were made on each year. These values were averaged to achieve decadal resolution for the 14C calibration. The relative uncertainty of the decadal 14C data was below 1% (2σ). The data are in good agreement with the existing dendrochronology and allow for high-resolution calibration for most years. Variations in the fine structure of the 14C time series preserved in this specimen demonstrate sporadic rapid increases in the Δ14C content of the surface ocean and atmosphere. Certain sharp rises in Δ14C are coincident with gaps in coral growth evidenced by several hiatuses. These may be related to rapid climatic changes that occurred during the Younger Dryas. This is the first coral calibration with decadal resolution and the only such data set to extend beyond the dendrochronology-based 14C calibration.
Variations of Radiocarbon in Tree Rings: Southern Hemisphere Offset Preliminary Results
Authors: McCormac F. G. , Hogg A. G. , Higham T. F. G. , Baillie M. G. L. , Palmer J. G. , Xiong Limin , Pilcher J. R. , Brown David , Hoper S. T.
Published: July 2016

The Queen's University of Belfast, Northern Ireland and University of Waikato, Hamilton, New Zealand radiocarbon laboratories have undertaken a series of high-precision measurements on decadal samples of dendrochronologically dated oak (Quercus patrea) and cedar (Libocedrus bidwillii) from Great Britain and New Zealand, respectively. The results show a real atmospheric offset of 3.4 ± 0.6% (27.2 ± 4.714C yr) between the two locations for the interval ad 1725 to ad 1885, with the Southern Hemisphere being depleted inl4C. This result is less than the value currently used to correct Southern Hemisphere calibrations, possibly indicating a gradient in Δ14C within the Southern Hemisphere.
A 23-Year Retrospective Blind Check of Accuracy of the Copenhagen Radiocarbon Dating System
Authors: Rasmussen Kaare L , Tauber Henrik , Bonde Niels , Christensen Kjeld , Theodórsson Páll
Published: July 2016

A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of the same age measured by Stuiver and Pearson (1993) for calibration purposes. The average difference was found to be 54 ± 72 14C yr. The results further indicate that the actual standard deviation is only 7% higher than that quoted by the laboratory. The investigation has shown a long-term stability of laboratory accuracy with no systematic laboratory variations either with respect to sample age or to the time of measurement from 1971 to 1993.
Radiocarbon Distribution in Northwest Belarus Near the Ignalina Nuclear Power Plant
Authors: Mikhajlov Nikolaj D , Kolkovsky Vladimir M , Pavlova Iren D
Published: July 2016

Since 1994, the Institute of Geological Sciences has undertaken an environmental monitoring program to measure radiocarbon levels in territory adjacent to active nuclear power plants (NPP). We determined 14C concentrations in natural objects from areas contiguous to Ignalina NPP as well as 14C background concentration in areas remote from the NPP. In the environs of the Ignalina station comparatively elevated levels of 14C were observed in vegetation and waters of Lake Drisvyaty. This appears to be a consequence of release of carbon radioisotope into the atmosphere and probably into waters of the lake during operation of the nuclear reactor.
Louvain Natural Radiocarbon Measurements VI
Authors: Gilot E.
Published: July 2016

The following list comprises a selected number of measurements made during 1966–67 with CH4 at 3 atm pressure in a 0.6 L proportional gas-counter as previously described. The B.P. ages are based upon a.d. 1950 and are calculated with a half-life of 5570 yr. The quoted error consists of experimental standard deviation including the counting variations of the unknown sample, the modern standard, and the background.