bluuebunny/crossref_metadata_2025 huggingface dataset:
Review of Tropospheric Bomb 14C Data for Carbon Cycle Modeling and Age Calibration Purposes
Authors: Hua Quan , Barbetti Mike
Published: July 2016

Comprehensive published radiocarbon data from selected atmospheric records, tree rings, and recent organic matter were analyzed and grouped into 4 different zones (three for the Northern Hemisphere and one for the whole Southern Hemisphere). These 14C data for the summer season of each hemisphere were employed to construct zonal, hemispheric, and global data sets for use in regional and global carbon model calculations including calibrating and comparing carbon cycle models. In addition, extended monthly atmospheric 14C data sets for 4 different zones were compiled for age calibration purposes. This is the first time these data sets were constructed to facilitate the dating of recent organic material using the bomb 14C curves. The distribution of bomb 14C reflects the major zones of atmospheric circulation.
Rolling Out Revolution: Using Radiocarbon Dating in Archaeology
Authors: Bayliss Alex
Published: July 2016

Sixty years ago, the advent of radiocarbon dating rewrote archaeological chronologies around the world. Forty years ago, the advent of calibration signaled the death knell of the diffusionism that had been the mainstay of archaeological thought for a century. Since then, the revolution has continued, as the extent of calibration has been extended ever further back and as the range of material that can be dated has been expanded. Now a new revolution beckons, one that could allow archaeology to engage in historical debate and usher in an entirely new kind of (pre)history. This paper focuses on more than a decade of experience in utilizing Bayesian approaches routinely for the interpretation of14C dates in English archaeology, discussing both the practicalities of implementing these methods and their potential for changing archaeological thinking.
Radiocarbon Reveals the Age of Two Precious Tombs in the Etruscan Site of Populonia-Baratti (Tuscany)
Authors: Scirè Calabrisotto C , Fedi M E , Taccetti F , Benvenuti M , Chiarantini L , Quaglia L
Published: July 2016

The archaeological site of Populonia-Baratti, in the southern part of Tuscany (Italy), was one of the most important centers in ancient Etruria, as seen in the evidence of metallurgical activities carried out at that time. During recent archaeological excavations (2005) in the ancient industrial area of Populonia, along the Baratti beach, 2 interesting tombs were found. The 2 graves were unusually located in an area dedicated to metallurgical activity and showed a particular structure of the burial chambers and an extreme richness in the grave goods. The unique character of the 2 tombs prompted many questions: who were these 2 individuals (a woman wearing many jewels and a tall, vigorous man) and when did they die? In order to obtain useful information about the chronology of the 2 tombs, accelerator mass spectrometry (AMS) radiocarbon analyses were performed on samples taken from the ribs of the 2 skeletons. Measured 14C ages were converted to calibrated ages using additional information derived from stable isotope ratios measured in the extracted collagen. Actually, the 13C data provided useful hints about the diet of the 2 individuals, thus allowing us to estimate the percentage of marine food consumed (about 30%) and exploit a combined marine-terrestrial calibration curve. As a result, the age of the 2 individuals can be dated to the 2nd century AD, during Roman times, which is in good agreement with the information obtained from archaeological, anthropological, and stylistic studies of the 2 tombs.
A New Robust Statistical Model for Radiocarbon Data
Authors: Andrés Christen J , Pérez E Sergio
Published: July 2016

The general method currently used to analyze radiocarbon data (y) is conditional on the standard deviation (σ), reported by14C laboratories, which reflects the uncertainty in the dating process. This uncertainty is measured through a series of empirical as well as theoretical considerations about the dating process, chemical preprocessing, etc. Nevertheless, σ is assumed as known in the statistical model for14C data used since the dawn of the discipline. This paper proposes a method for the analysis of14C data where the associated variance is taken as the product of an unknown constant α with the sum of the variance reported by the laboratory σ2and the variance of the calibration curve σ2(θ) (that is, an unknown error multiplier). Using this approach, assuming that the14C determinationyarises from a Normal population and that,a priori,α has an inverse gamma distribution InvGa(a, b), the resulting dating model is atdistribution with 2adegrees of freedom. The introduction of parametersaandballows a robust analysis in the presence of atypical data and at the same time incorporates the uncertainty associated with the intra- and interlaboratory error assessment processes. Comparisons with the common Normal model show that the proposedtmodel produces smoother posterior distributions and seem to be far more robust to atypical data, presenting a simpler alternative to the standard14C outlier analysis. Moreover, this new model might be a step forward in understanding and explaining the otherwise elusive scatter in14C data seen in interlaboratory studies.
A Multiscalar Approach to Modeling the End of the Neolithic on the Great Hungarian Plain Using Calibrated Radiocarbon Dates
Authors: Yerkes Richard W , Gyucha Attila , Parkinson William
Published: July 2016

This article presents the results of a multiscalar analysis of 168 radiocarbon dates from Neolithic and Copper Age sites on the Great Hungarian Plain. We examined chronological patterns at different geographic scales to explore socioeconomic changes that occurred during the transition from the Neolithic to the Copper Age. The beginning and end of the Late Neolithic (5000–4500 cal BC) and Early Copper Age (4500–4000 cal BC) were modeled with14C dates calibrated with the CALIB 5.01 program and IntCal04 calibration curve. Our attempts to identify chronological subphases within these 500-yr-long periods were confounded by multiple intercepts in the calibration curve. The analysis indicated that terminal Late Neolithic (4700–4300 cal BC) and “transitional” Proto-Tiszapolgár occupations (4600–4250 cal BC) at tell sites were contemporary with initial Early Copper Age habitations (4450–4250 cal BC). Calibrated dates from small Early Copper Age settlements at Vészto-Bikeri and Körösladány-Bikeri document changes in community and household organization that took place over several decades during the transition to the Copper Age. Bayesian analysis indicated that the small fortified sites were occupied contiguously in phases of 30–50 yr. The younger Körösladány-Bikeri site was established before the older Vészto-Bikeri site was abandoned. When large nucleated Late Neolithic communities dispersed and established small Early Copper Age settlements, the pattern of vertical accretion that had created the Late Neolithic tells gave way to a pattern of horizontal settlement accretion at the smaller settlements.
14C Dating of a Final Neolithic-Early Bronze Age Transition Period Settlement at Aghios Ioannis on Thassos (North Aegean)
Authors: Maniatis Y , Papadopoulos S
Published: July 2016

The transitional period known as the Final Neolithic-Early Bronze Age in Greece, falling in terms of absolute dates within the 4th millennium BC, is an obscure and enigmatic period. Few sites in northern Greece or the southern Balkans have produced evidence of 4th millennium BC occupation, and the sites that do are mainly concentrated in the last third of the 4th millennium toward the beginning of the EBA. This paper presents archaeological evidence and radiocarbon dates from a site that covers part of the gap, Aghios Ioannis on Thassos, the northernmost Aegean island. It is a coastal site of seasonal occupation and most probably depended on organized animal husbandry plus hunting and fishing activities. From the first excavations in 1996, there was evidence that the site was occupied during the Final Neolithic to the beginning of the Early Bronze Age. The 14C dates obtained fall towards the end of the 4th millennium if not closer to the middle. The presence of human activity in this last part of the 4th millennium “gap” on Thassos is by itself an interesting discovery that enlarges our knowledge for this obscure period and is of environmental and cultural significance.
The Influence of Soil Organic Matter Age Spectrum on the Reconstruction of Atmospheric 14C Levels Via Stalagmites
Authors: Fohlmeister J , Kromer B , Mangini A
Published: July 2016

The imprint of the radiocarbon bomb peak was detected in the top of stalagmite ER-77 from Grotta di Ernesto (NE Italy). This recently grown stalagmite reveals a reservoir age, also known as dead carbon fraction (dcf), of ≃1050 14C yr, or 12%. By applying a 14C soil-karst model, the age spectrum of soil organic matter (SOM) as well as the CO2 contribution of the single SOM reservoirs to the total soil CO2 can be derived. Under the assumption of constant vegetation, meaning both vegetation density and the age spectrum of SOM, it is possible to derive the soil-air 14C activity of the past using the 14C calibration curve (IntCal04). Hence, it is also possible to calculate an artificial stalagmite 14C data set covering the last 25,000 yr with parameters determined for stalagmite ER-77. With this artificially constructed data set, we derived the hypothetical atmospheric 14C activity by using the common method of applying a constant dcf on the modeled 14C data set of the stalagmite. This theoretical approach allows to analyze the impact of a constant and variable SOM age spectrum on atmospheric 14C reconstructions performed with real stalagmite 14C measurements. We observe deviations between IntCal04 and the atmospheric 14C activity as derived with our modeled 14C data set, which are larger for older SOM than for younger SOM and vary in time up to 2 pMC, depending on the strength of the variations in the atmospheric 14C level. This value is comparable with the 1-σ uncertainty given by IntCal04 for the last glacial. For a varying SOM age spectrum, the deviations between the calibration curve and 14C level of the atmosphere reconstructed with a stalagmite exceed 3 pMC, which is larger than the 1-σ uncertainty of IntCal04. In general, the SOM has smoothing, shifting, and 14C-depleting effects on the stalagmite 14C record and, therefore, on the stalagmite-derived atmospheric 14C activity. In this study, changes in soil-air pCO2 and carbonate dissolution conditions, which have also an important impact on the 14C record of a stalagmite, are not accounted for.
Development of Radiocarbon Dating Method for Degraded Bone Samples from Korean Archaeological Sites
Authors: Kim K J , Hong W , Park J H , Woo H J , Hodgins G , Jull A J T , Lee Y J , Kim J Y
Published: July 2016

The development of radiocarbon dating for degraded bone samples collected at Korean archaeological sites has been successful through the characterization of raw bone C/N ratios and application of an ultrafiltration method. It was found that the C/N ratios of raw bone samples are inversely proportional to the carbon content and residue amount after gelatinization. We have examined a few dozen Korean archaeological bone samples for this study. Well-preserved bone samples are found to be physically dense. The range of C/N ratios of Korean raw bone samples ranged from 3.4 to 74. We found that the C/N ratios of degraded raw bone samples can be used to determine whether 14C samples are acceptable for normal pretreatment processing and eventual dating. The results of this study support that even if the C/N ratio of a degraded raw bone sample is 11, extraction of collagen for bone dating is feasible by a carefully designed ultrafiltration process. Our preliminary 14C dating results of a depth profile of Gunang-gul Cave, an archaeological site in Danyang, Korea, indicate that this site has been either geologically or anthropologically disturbed in the past, with 14C ages ranging from 28,910 ± 200 to 48,090 ± 1050 yr BP. The C/N ratios of the collagen samples of Gunang-gul were determined to be 3.2–3.6. Our study establishes a new guide for the pretreatment of degraded bone samples such as those collected in Korea for 14C dating.
Radiocarbon Dating of Alkenones from Marine Sediments: II. Assessment of Carbon Process Blanks
Authors: Mollenhauer Gesine , Montluçon Daniel , Eglinton Timothy I
Published: July 2016

We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone 14C dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the procedure does not lead to a systematic bias of the results of alkenone dating to either younger or older ages. Our results indicate that alkenones record Δ14C of ambient DIC with an accuracy of approximately 10‰. A conservative estimate of measurement precision is 17‰ for modern samples. Alkenone 14C ages are expected to be reliable within 500 yr for samples younger than 10,500 14C yr.
Paleoproductivity Variations in the Equatorial Arabian Sea: Implications for East African and Indian Summer Rainfalls and the El Niño Frequency
Authors: Tiwari Manish , Ramesh Rengaswamy , Bhushan Ravi , Somayajulu B L K , Jull A J Timothy , Burr George S
Published: July 2016

We analyzed a sediment core from the equatorial Arabian Sea, chronologically constrained by accurate accelerator mass spectrometry (AMS) radiocarbon dates on selected planktonic foraminiferal species, for paleoproductivity variations corresponding to the variations in the Indian Ocean Equatorial Westerlies (IEW). The IEW in turn are positively correlated to the Southern Oscillation Index (SOI), which is a measure of El Niño, Southwest monsoon (SWM), and east African rainfall (EAR). The productivity data show that Indian and east African rainfalls declined from 35,000 calendar yr BP up to the last glacial maximum (LGM), with the maximum El Niño frequency during the last glacial period. From ∼14,500 to ∼2000 calendar yr BP (i.e. core top), we find strengthening SWM and EAR along with declining El Niño frequency.
Testing the Limits: Radiocarbon Dating and the End of the Late Bronze Age
Authors: Hagens Graham
Published: July 2016

Archaeometry is becoming an increasingly important tool in chronological research related to events in the Ancient Near East during the 2nd millennium BCE. This paper is a review of recently published radiometric results in an attempt to establish the probable dating range for one particular event that occurred during the last quarter of that millennium, the end of the Late Bronze Age. The conclusion is that in spite of significant improvements in methodology in recent years, the quantity and quality of radiocarbon data are still insufficient to define the range of that date to much better than a century. It is concluded that the most likely date of the Late Bronze/Iron Age transition (here defined by the arrival of Mycenaean LH IIIC:1b pottery in the Levant) is somewhere in the 8-decade range between ∼1170 to 1100 BCE. A comparative study of archaeological and historical evidence would appear to favor the lower value.
Dating Paleosol and Animal Remains in Loess Deposits
Authors: Zhang H C , Li B , Yang M S , Lei G L , Ding H , Niu Jie , Fan H F , Zhang W X , Chang F Q
Published: July 2016

Accurate and reliable dating of paleosols, animal remains, and artifacts is of crucial importance in reconstructing environmental change and understanding the interrelationship between human activities and natural environments. Dating different materials in the same sample can help resolve problems such as soil carbon sources and carbon storage state. Conventional radiocarbon dating of soil (inorganic and organic matter) and accelerator mass spectrometry (AMS) dating of animal remains (fossil bones and teeth) result in different ages for materials from the same sample position in a typical loess section at Xinglong Mountain, Yuzhong County, Gansu Province in NW China. Inorganic matter is ∼3400 yr older than organic matter, 4175 ± 175 cal BP to 3808 ± 90 cal BP. A 1610-yr difference between the 14C ages of fossils (animal bones and teeth) and soil organic matter suggests that a depositional hiatus exists in the studied profile. The varying 14C ages of fossils and soil organic and inorganic matter have important implications for paleoclimate reconstructions from loess sections. It is critical to consider the meaning of the variable 14C ages from different material components from the same sample position in terms of soil organic and inorganic carbon storage, vegetation history reconstruction, archaeology, and the study of ancient civilizations.
A Direct Estimate of the Initial Concentration of 14C in the Mountain Aquifer of Israel
Authors: Carmi Israel , Kronfeld Joel , Yechieli Yoseph , Boaretto Elisabetta , Bar-Matthews Miryam , Ayalon Avner
Published: July 2016

Five radiocarbon analyses were performed on 5 different sources within Soreq Cave, which was used as a model for the Judea Group Aquifer of Israel (pMCq0). The transit time of rainwater through the roof of the cave to sources within it had been determined with tritium. From this information, the year of deposition of rain on the roof of the cave, which later appeared in one of the sources, was estimated and the atmospheric 14C concentration at that time was ascertained (pMCa0). The parameter Q = pMCq0 / pMCa0 was found to be Q = 0.60 ± 0.04. This makes it possible to calculate the age of water in any well in the Judea Group Aquifer of Israel by measuring its 14C concentration (pMCqt) by use of the decay equation and applying Q.
Radiocarbon in the Water Column of the Southwestern North Pacific Ocean—24 Years After Geosecs
Authors: Povinec Pavel P , Aramaki Takafumi , Burr George S , Timothy Jull A J , Liong Wee Kwong Laval , Togawa Orihiko
Published: July 2016

In the framework of the Worldwide Marine Radioactivity Studies (WOMARS) project, water profile samples for radiocarbon measurements were taken during the IAEA'97 cruise at 10 stations in the southwestern North Pacific Ocean. While 14C concentrations were rapidly decreasing from the surface (Δ14C about 100‰) down to about 800 m at all visited stations (Δ14C about −200‰), the concentrations below 1000 m were almost constant. Some stations were in proximity to the GEOSECS stations sampled in 1973; thus, 14C profiles could be compared after a 24-yr interval. Generally, 14C concentrations had decreased in surface waters (by 50–80‰) and increased (by about the same amount) in intermediate waters when compared with GEOSECS data. In deep waters (below 1000 m), the observed 14C concentrations were similar to GEOSECS values. The bomb-produced 14C inventory had increased by more than 20% over the 24 yr from 1973 to 1997 and was estimated to be about (32 ± 5) 1012 atom m-2, with an annual 14C flux of (1.3 ± 0.3) 1012 atom m-2 yr-1. The results suggest that bomb-produced 14C has been advected northwards by the Kuroshio Current and the Kuroshio Extension and stored in the intermediate layer as North Pacific Intermediate Water.
Marine Reservoir Correction for the Cocos (Keeling) Islands, Indian Ocean
Authors: Hua Quan , Woodroffe Colin D , Barbetti Mike , Smithers Scott G , Zoppi Ugo , Fink David
Published: July 2016

Known-age corals from the Cocos (Keeling) Islands, Indian Ocean, have been analyzed by accelerator mass spectrometry (AMS) for radiocarbon to determine marine reservoir age corrections. The ΔR value for the Cocos (Keeling) Islands is 66 ± 12 yr based on the analyses undertaken for this study. When our AMS and previously published dates for Cocos are averaged, they yield a ΔR of 64 ± 15 yr. This is a significant revision of an earlier estimate of the ΔR value for the Cocos (Keeling) Islands of 186 ± 66 yr (Toggweiler et al. 1991). The (revised) lower ΔR for the Cocos (Keeling) Islands is consistent with GEOSECS14C data for the Indian Ocean, and previously published bomb14C data for the Red Sea, Gulf of Aden, and Cocos Islands. The revised ΔR is also close to values for the eastern Indian Ocean and adjacent seas. These suggest surface waters that reach the Cocos Islands might be partly derived from the far western Pacific, via the Indonesian throughflow, and might not be influenced by the southeast flow from the Arabian Sea.
Radiocarbon Reservoir Ages from Freshwater Lakes, South Georgia, Sub-Antarctic: Modern Analogues from Particulate Organic Matter and Surface Sediments
Authors: Moreton Steven G , Rosqvist Gunhild C , Davies Sarah J , Bentley Michael J
Published: July 2016

Lake sediments have the potential to preserve proxy records of past climate change. Organic material suitable for radiocarbon dating often provides age control of such proxy records. Six shallow freshwater lakes on the sub-Antarctic island of South Georgia were investigated for carbon reservoir effects that may influence age-depth profiles from lake sediment records in this important region. Paired samples of particulate organic matter (POM) from the water column and surface sediment (bulk organic carbon) were analyzed by accelerator mass spectrometry14C. POM in 4 lakes was found to be in equilibrium with the atmosphere (~107% modern), whereas 2 lakes showed significant depletion of14C. In each lake, the surface sediment ages were older than the paired POM age. Surface sediment ages showed a much greater range of ages compared to the equivalent POM ages, even for lakes located in close proximity. We conclude that sediment disturbance during coring, bioturbation, and periodic resuspension of sediments are likely factors causing the difference in the apparent age of surface sediments.
Carbon Isotopic Composition of Tree Rings as A Tool for Biomonitoring CO2 Level
Authors: Pawełczyk Sławomira , Pazdur Anna
Published: July 2016

Carbon isotopes are widely used as indicators in the study of atmospheric CO2 variability in space and time. Preliminary results are part of a project investigating 13C and 14C concentration changes during the last 150 yr in Poland, both in industrial and ecologically clean regions, using annual tree rings (Pinus sylvestris, Populus nigra). The results describe the local Suess effect recorded in the industrial Kraków and Upper Silesia regions compared to changes of background radiocarbon concentration caused by global human activity in a “clean region,” Augustów Wilderness. The δ13C record also shows the influence of the local Suess effect.
An AMS14C Pollen-Dated Sediment and Pollen Sequence from the Late Holocene, Southern Coastal Hawke'S Bay, New Zealand
Authors: Chester Pamela I , Prior Christine A
Published: July 2016

Hawke's Bay is a region of New Zealand where earliest settlement of indigenous people may have occurred. A sedimentological and palynological study of lake sediments from a small catchment was undertaken to reconstruct erosion, vegetation, and fire histories to determine human environmental impact, and thus add to knowledge of the timing of initial settlement of New Zealand. Precise dating was an essential facet of the research because of the short time span of human occupation in New Zealand. A chronology is proposed based on accelerator mass spectrometry (AMS) radiocarbon dating of palynomorph concentrates. Known-age tephras were used as a check on the validity of the14C ages obtained using this technique, which is being developed at Rafter Radiocarbon Laboratory. Two episodes of sustained erosion occurred between about 1500 and 1050 BC with a period of ~50 yr at about 1300 BC when no erosion occurred. Five episodes of erosion of very short duration occurred at about 625 BC, 450 BC, 100 BC, AD 950, and AD 1400. Erosion probably resulted from landslides induced by earthquakes or severe storms, with the exception of the last event which coincides with local burning and is probably a consequence of this. A conifer/broadleaved forest surrounded the lake until soon after AD 1075–1300, when a dramatic decline in pollen of forest plants and an increase in charcoal occurred. Forest was replaced by fire-induced scrub, interpreted as a result of anthropogenic burning by prehistoric Polynesians. A further decline in woody vegetation occurred when European-introduced plants appear in the pollen record and extensive pasture was established.
14C Sources and Distribution in the Vicinity of La Hague Nuclear Reprocessing Plant: Part I—Terrestrial Environment
Authors: Fontugne M , Maro D , Baron Y , Hatté C , Hebert D , Douville E
Published: July 2016

COGEMA-La Hague nuclear reprocessing plant in the Cotentin Peninsula (northwest France) releases in the atmosphere about 19 TBq.yr-1 of radiocarbon. Three experiments in a terrestrial environment with sampling of a bio-indicator like furze were performed in 1997, 1998, and 1999, and additional air samples in the chimney plume were measured. Results presented here establish the 14C distribution in the La Hague environment and suggest that a part of the 14C content in the vegetation near the coast results from a 14CO2 degassing of seawater supplied with the liquid waste from the nuclear plant.
Sellafield-Derived Anthropogenic 14C in the Marine Intertidal Environment of the NE Irish Sea
Authors: Cook G T , MacKenzie A B , Muir G K P , Mackie G , Gulliver P
Published: July 2016

The intertidal biota from Parton beach, close to the Sellafield nuclear fuel reprocessing plant, were all found to be enriched in radiocarbon relative to ambient background. The degree of enrichment appears to reflect the positions of the biota in the food chain once the dilution in seaweed from atmospheric uptake is taken into account. Close to the low-water mark, the order was mussels > limpets > anemones winkles > seaweed. The same order was observed close to the high-water mark, except that anemones were absent from this area. The activities in the biogeochemical fractions of the water column reflect the fact that discharges are primarily in the form of dissolved inorganic carbon (DIC), which is subsequently transferred to the particulate organic carbon (POC) and, to a lesser extent, the dissolved organic carbon (DOC), and finally, the particulate inorganic carbon (PIC). Analysis of intertidal sediment suggests that there is likely to be a gradual increase in the specific activity of 14C in the inorganic component of this material as Sellafield contaminated organisms die and their shells are ground down by natural processes.
Tree-Ring Records of Near-Younger Dryas Time in Central North America—Preliminary Results from the Lincoln Quarry Site, Central Illinois, Usa
Authors: Panyushkina Irina P , Leavitt Steven W , Wiedenhoeft Alex , Noggle Sarah , Curry Brandon , Grimm Eric
Published: July 2016

The abrupt millennial-scale changes associated with the Younger Dryas (YD) event (“chronozone”) near the dawn of the Holocene are at least hemispheric, if not global, in extent. Evidence for the YD cold excursion is abundant in Europe but fairly meager in central North America. We are engaged in an investigation of high-resolution environmental changes in mid-North America over several millennia (about 10,000 to 14,000 BP) during the Late Glacial–Early Holocene transition, including the YD interval. Several sites containing logs or stumps have been identified and we are in the process of initial sampling or re-sampling them for this project. Here, we report on a site in central Illinois containing a deposit of logs initially thought to be of YD age preserved in alluvial sands. The assemblage of wood represents hardwood (angiosperm) trees, and the ring-width characteristics are favorable to developing formal tree-ring chronologies. However, 4 new radiocarbon dates indicate deposition of wood may have taken place over at least 8000 14C yr (6000–14,000 BP). This complicates the effort to develop a single floating chronology of several hundred years at this site, but it may provide wood from a restricted region over a long period of time from which to develop a sequence of floating chronologies, the timing of deposition and preservation of which could be related to paleoclimatic events and conditions.
The Comparison of 14C Wiggle-Matching Results for the ‘Floating’ Tree-Ring Chronology of the Ulandryk-4 Burial Ground (Altai Mountains, Siberia)
Authors: Kuzmin Yaroslav V , Slusarenko Igor Y , Hajdas Irka , Bonani Georges , Andres Christen J
Published: July 2016

Two independent 14C data sets of 10 tree-ring samples from the longest master chronology of the Pazyryk cultural complex were obtained and wiggle-matched to the absolute timescale. The results show very good agreement, within 10–15 calendar yr. The Ulandryk-4 burial ground (mound 1) was dated to about 320–310 cal BC, and this is consistent with wiggle-matching of the Pazyryk burial ground date series.
Variation of the Radiocarbon Content in Tree Rings During the Spoerer Minimum
Authors: Miyahara Hiroko , Masuda Kimiaki , Furuzawa Hideki , Menjo Hiroaki , Muraki Yasushi , Kitagawa Hiroyuki , Nakamura Toshio
Published: July 2016

This paper presents the variation of radiocarbon content in annual tree rings for the period AD 1413–1553, which includes the Spoerer Minimum period (AD 1415–1534). Since the variation of the production rate of 14C is strongly related to solar activity, the variation of 14C content in annual tree rings gives us information on the characteristics of variation of solar activity. We have studied solar activity during the grand solar minima, focusing especially on the stability of the 11-yr cycle. The minima are determined to have been almost free of sunspots. Our results, however, have revealed quite remarkably the existence of the 11-yr cycle for most of the time during the Spoerer Minimum. The 11-yr variation weakened around AD 1460–1510, suggesting that solar activity might have been strongly suppressed during these 50 yr.
Bayesian Periodic Signal Detection Applied to Intcal98 Data
Authors: Palonen V , Tikkanen P
Published: July 2016

A Bayesian multiple-frequency model has been developed for spectral analysis of data with unknown correlated noise. A description of the model is given and the method is applied to decadal atmospheric INTCAL98 Δ14C data. The noise of the INTCAL98 data is found to be red, and there seems to be no support for continuous harmonic frequencies in the data.
Freiberg Radiocarbon Measurements I
Authors: Burkhardt Wolfgang , Stechemesser Hajo , Mania Dietrich
Published: July 2016

This list reports the first age determinations carried out by the Freiberg Radiocarbon Dating Laboratory. The preparation of samples and radiocarbon dates were done by the first two authors, who constructed the apparatus; sample descriptions and interpretations of dates were made by the third author.
Louvain Natural Radiocarbon Measurements VIII
Authors: Gilot E.
Published: July 2016

The measurements reported in this list were made in the Louvain C14 Dating Laboratory in 1968 with the 0.6L CH4 proportional counter. The counter generally operates at 3 atm pressure. Samples too poor to provide 2 L methane are measured at 1000 mm Hg pressure. Ages are calculated on the basis of a C14 half life of 5570 yr and are quoted with 1σ counting error. The description of each sample is based on information provided by the submitters.
National Taiwan University Radiocarbon Measurements I
Authors: Hsu Yuin-Chi , Huang Chia-Yi , Lu Shih-Chong
Published: July 2016

Natural C14 measurements have been performed at the Dept. of Physics, National Taiwan University since 1965, using a cylindrical proportional counter of 1000 ml (Hsu et al., 1965). The proportional counter is operated with CO2 as the filling gas at a pressure of 1216 mm Hg at room temperature of 20°C. Working voltage is 4.7 Kv, with a plateau length of more than 700 v and a plateau slope of ca. 1% per 100 v. Background is reduced to 5.1 counts/min and the counting rate of the NBS oxalic acid standard is 9.4 counts/min at the normal counting pressure of 1216 mm Hg.
Uppsala Radiocarbon Measurements X
Authors: Olsson Ingrid U. , Klasson Martin
Published: July 2016

The following list covers samples measured since the last list of atmospheric samples (Radiocarbon, 1967, v. 9, p. 471–476) was written, to determine the increase of the C14/C12 ratio due to explosion of nuclear devices.
Geological Survey of Canada Radiocarbon Dates I
Authors: Dyck W. , Fyles J. G.
Published: July 2016

This paper reports the first ages determined in the C14Dating Laboratory of the Geological Survey of Canada. The C14dating program of the Geological Survey is a cooperative project; geologists of the Pleistocene Section assess and select samples for dating, and the Isotope and Nuclear Research Section, under Dr. R. K. Wanless, developed and operates the laboratory and calculates ages. The first part of this paper, devoted to sample preparation, counting procedure, and interlahoratory check dates was prepared by the first author, who built and operates the laboratory. The date list was compiled by the second author from descriptions of samples and interpretations of dates provided by various collectors. Most samples analyzed so far have originated within the Geological Survey.
Copenhagen Radiocarbon Dates V
Authors: Tauber Henrik
Published: July 2016

The following list includes samples dated in the period 1956–1961.

Age calculations are based on a contemporary value equal to 95% of the activity of the NBS oxalic-acid standard, and on a half life for C14of 5568 ± 30 yr.
University of Texas Radiocarbon Dates I
Authors: Stipp J. J. , Davis E. Mott , Noakes John E. , Hoover Tom E.
Published: July 2016

The C14Dating Laboratory of the University of Texas has been working on the development of two systems of counting: gas counting with methane, and liquid scintillation counting with benzene. Lack of adequate instrumentation has retarded the work on gas counting, but the liquid scintillation work, supported in part by the Department of Chemistry, finally led to the successful development of a system in which the benzene counting solvent was synthesized from acetylene by pyrolysis (Tamers, Stipp, and Collier, 1961).
University of Pennsylvania Radiocarbon Dates V
Authors: Ralph Elizabeth K. , Stuckenrath Robert
Published: July 2016

In conformance with the request of the editors, ages in this date list have been calculated with the Libby half life value, 5568 ± 30 yr. We should like to mention, however, that the “effective” and, possibly, the true value may differ from this by several hundred years (see discussion by Kohler and Ralph, 1961). The measurements of samples of known age indicate that the “effective” half life value is close to 5800 yr, except for specific recent periods.
Arizona Radiocarbon Dates III
Authors: Damon Paul E. , Long Austin
Published: July 2016

Radiocarbon-age measurements reported here were made by the carbon dioxide gas-proportional counting method since conversion of the laboratory from the solid-carbon method. Assembly of the shield and construction of the glass system was accomplished during the summer of 1959. By January 1960, shield, anticoincidence ring, counters and electronics were set up and in operation. The first year of operation was occupied with calibration, comparison of dating with other C14laboratories, and the repeating of many of the analyses previously made by the solid-carbon method. Special attention was given to dates open to question from an archaeologic point of view.
UCLA Radiocarbon Dates II
Authors: Fergusson G. J. , Libby W. F.
Published: July 2016

The measurements reported in this list have been made in the Isotope Laboratory at the Institute of Geophysics, UCLA during 1962. Dates have been calculated on the C14 half life of 5568 years and using 95% NBS oxalic acid as modern standard, in agreement with the decision of the Fifth Radiocarbon Dating Conference (Godwin, 1962).
Geological Survey of Canada Radiocarbon Dates II
Authors: Dyck W. , Fyles J. G.
Published: July 2016

The accompanying date list includes age determinations completed during the period December 1, 1961 to November 1, 1962. All measurements were made with the 2 L counter described in our first date list (GSC I). Sample preparation, counting procedures, and calculation of dates were as described in GSC I except as outlined below:

a.

Base and acid treatments were carried out with 1N HCl and 2% NaOH instead of 2N HCl and 4% NaOH, because the less-concentrated solutions were still strong enough to accomplish the desired purification.

b.

The Mg(C104)2 drying columns were removed from the purification train in order to test their effect, if any, on the purity of the gas. Since there was no detectable change in the purity of the gas these columns were left out of the purification line.

c.

Ages were calculated using 0.950 of the activity of the N.B.S. oxalic-acid standard as the reference activity and a.d. 1950 as the zero reference year, in line with the recommendations of the editors of Radiocarbon.
University of Pennsylvania Radiocarbon Dates VI
Authors: Stuckenrath Robert
Published: July 2016

In conformance with the request of the editors, ages in this date list have been calculated with the Libby half life value of 5568 ± 30 yr, although the present best estimate of the half life value is 5730 ± 40 yr (Godwin, 1962). Additional support for the latter value as being closer to the “effective” value for dating has been obtained by the measurements of samples of known age.
British Museum Natural Radiocarbon Measurements IV
Authors: Barker Harold , Mackey John
Published: July 2016

The following list comprises measurements made to the end of September 1961, when the equipment had to be dismantled for removal into new premises at 39 Russell Square, London W.C.1. The technique used is as described previously (Barker and Mackey, 1959) and as in previous lists, the error terms are not based solely on counting statistics but are widened to include contributions of ± 80 yr for possible isotopic fractionation effects and ± 100 yr for the de Vries-effect. NBS oxalic acid is used as the reference standard and ages are calculated on a half life of 5568 yr and expressed as years b.p. (before 1950 a.d.) and also in terms of the Christian calendar.
Gakushuin Natural Radiocarbon Measurements II
Authors: Kigoshi Kunihiko , Endo Kunihiko
Published: July 2016

This date list covers many of the datings done from November 1961 to October 1962. Technique described in Gakushuin I (Gakushuin I) is virtually unchanged, using 900-ml acetylene-filled proportional counter (Counter 1) with multiple-anode anti-coincidence ring counter.
Groningen Radiocarbon Dates IV
Authors: Vogel J. C. , Waterbolk H. T.
Published: July 2016

An attempt has been made to assemble the large number of C14 dates measured in Groningen since the last date list was published in 1958. We have not succeeded in preparing all the measurements done in this time; the present list contains a more or less random selection. It is hoped the rest will be included in next year's list.
Geological Survey of Finland Radiocarbon Measurements II
Authors: Hyyppä E. , Isola A. , Hoffrén V.
Published: July 2016

The following results represent measurements carried out since our first date list was prepared. Nearly all the dates given were obtained by using two proportional counters. The pretreatment of the samples and the production of pure CO2 followed the method described in Finland I.
Bern Radiocarbon Dates III
Authors: Gfeller Chr. , Oeschger H.
Published: July 2016

This list covers part of the measurements made at the Radiocarbon Dating Laboratory, Physics Department, University of Bern from summer 1960 until summer 1962. Two low-level counters with incorporated anticoincidence arrangement (Houtermans and Oeschger, 1958) are used for routine C14 measurements.
University of Rome Carbon-14 Dates III
Authors: Alessio M. , Bella F. , Bachechi F. , Cortesi C.
Published: July 2016

The following list comprises age measurements carried out between December 1963 and September 1964. The samples dated are almost all of archaeological interest and are drawn from Italian and Egyptian territory.
Saclay Natural Radiocarbon Measurements II
Authors: Delibrias G. , Guillier M. T. , Labeyrie J.
Published: July 2016

The list of dates grouped below represents datings made during 1963. The method and the counting techniques have been previously described (Radiocarbon, v. 6, Saclay I).
Smithsonian Institution Radiocarbon Measurements II
Authors: Long Austin
Published: July 2016

These analyses were performed from November 1963 to November 1964 with equipment and techniques essentially unchanged since the previous date list. Unless otherwise noted all samples were submitted by Smithsonian staff members, each of whom was most helpful in supplying information pertaining to the samples and in discussion of results.
University of Wisconsin Radiocarbon Dates I
Authors: Bender Margaret M. , Bryson Reid A. , Baerreis David A.
Published: July 2016

A radiocarbon dating laboratory was installed at the University of Wisconsin in 1963 as part of a program of climatic research in which meteorologists, archaeologists, chemists, botanists, limnologists, geologists, and soil scientists are cooperating.
Physical Research Laboratory Radiocarbon Date List IV
Authors: Agrawal D P , Krishnamurthy R V , Kusumgar Sheela , Pant K K
Published: July 2016

The dates presented below are from some important archaeologic and Quaternary sites. All the dates are in years bp, based on τ½ = 5568 years. When converting archaeologic dates into the ad/bc scale, 1950 should be used as the base year. The dates are not corrected for 13C fractionation. All the dates older than 10,000 years have been given with 2σ errors.
Arizona Radiocarbon Dates X
Authors: Long Austin , Muller A B
Published: July 2016

Routine radiocarbon analyses were last reported for the Laboratory of Isotope Geochemistry at the University of Arizona in 1971 (Haynes, Grey, and Long, 1971), and a special date list on packrat middens appeared in 1978 (Mead, Thompson, and Long, 1978). This list presents results obtained from our gas proportional counting facility before its major renovation and before the addition of a liquid scintillation counting system. The characteristics of these new systems will be described in the next date list.
Institut Royal du Patrimoine Artistique Radiocarbon Dates VIII
Authors: Dauchot-Dehon Michèle , Strydonck Mark Van , Heylen Jos
Published: July 2016

This list contains most of the measurements made during 1980, since our last list (R, 1981, v 23, p 33-37). A second methane synthesis unit became operational (Dauchot-Dehon and Van Strydonck, 1979) at the end of 1979. Basically, this unit is the same as the one built earlier (Klebert and Heylen, 1966).
University of Miami Radiocarbon Dates XXI
Authors: Crabtree Sharon , Stipp J J
Published: July 2016

The following radiocarbon dates are a partial list of samples measured for a variety of projects and materials since August 1980. Chemical and counting procedures remain the same as indicated in R, v 20, p 274-282.
AMS Radiocarbon Dating of Ancient Iron Artifacts: A New Carbon Extraction Method in Use at LLNL
Authors: Cook Andrea C , Wadsworth Jeffrey , Southon John R
Published: July 2016

A new sealed double tube combustion method was developed at Lawrence Livermore National Laboratory (LLNL) to extract carbon from modern steels and ancient iron artifacts. Iron samples were chemically pretreated with 10% nitric acid, vacuum sealed in 6 mm quartz tubes with CuO, vacuum sealed again inside 9 mm quartz tubes, and combusted at 1000 °C for a minimum of 10 hr. The resulting CO2 was graphitized routinely using hydrogen reduction (Vogel et al. 1989). After the initial phase of development, carbon yields of 100% were consistently obtained. The activities of two modern high carbon steels (treated as process blanks, manufactured using only coal as the carbon source) were determined to be 0.0077 ± 0.0009 (n = 12, ± 1 σ) for a 1.3% C steel and 0.0090 ± 0.0038 (n = 12, ± 1 σ) for a 1.9% C steel, indicating that very little contamination is introduced during the sample preparation process. Since the Iron Age began less than 5000 years ago, these background uncertainties should introduce errors of no more than ±30 years to the radiocarbon ages of actual artifacts. Two ancient iron artifacts of known date were analyzed and demonstrate that the new methodology can be used to obtain the correct date of manufacture for iron objects, provided that they are made exclusively using charcoal that was contemporaneous with the manufacture of the artifact. Since only 1 mg of carbon is required for accelerator mass spectrometry (AMS), very small iron samples can now be analyzed (50 mg of a 2.0% C iron or 1 g of a 0.1% C iron). We anticipate that this methodology will be particularly useful to archeologists who currently have to rely on context to date iron artifacts.
Progress in Radiocarbon Target Preparation at the Antares AMS Centre
Authors: Hua Q , Jacobsen G E , Zoppi U , Lawson E M , Williams A A , Smith A M , McGann M J
Published: July 2016

We present routine methods of target preparation for radiocarbon analysis at the ANTARES Accelerator Mass Spectrometry (AMS) Centre, as well as recent developments which have decreased our procedural blank level and improved our ability to process small samples containing less than 200 μg of carbon. Routine methods of14C sample preparation include sample pretreatment, CO2extraction (combustion, hydrolysis and water stripping) and conversion to graphite (graphitization). A new method of cleaning glassware and reagents used in sample processing, by baking them under a stream of oxygen, is described. The results show significant improvements in our procedural blanks. In addition, a new graphitization system dedicated to small samples, using H2/Fe reduction of CO2, has been commissioned. The technical details of this system, the graphite yield and the level of fractionation of the targets are discussed.
Development of a Semi-Automated System for Routine Preparation of Carbonate Samples
Authors: Tisnérat-Laborde N , Poupeau J J , Tannau J F , Paterne M
Published: July 2016

We constructed a semi-automated system to transform carbonate samples to CO2, as a means to increase sample-processing capacity. The physico-chemical process includes hydrolysis of carbonate, quantification of the mass of carbon and CO2 collection in a glass ampoule. The system is computer-controlled and monitored, and all the data are stored. A single run of five consecutive samples requires about 3.5 hours. Measurements of 14C concentrations were made on samples of IAEA C-1 Carrara marble to test the reliability of this semi-automated system. These measurements have allowed the determination of the total system background and the memory effect of our system.
PRIME Lab Sample Handling and Data Analysis for Accelerator-Based Biomedical Radiocarbon Analysis
Authors: Hillegonds Darren J , Record Rae , Rickey Frank A , Badylak Steve , Jackson George S , Simmons-Byrd Abby , Elmore David , Lipschutz Michael E
Published: July 2016

Processing and measurement of 200 biomedical samples has provided an opportunity to better understand the characteristics of accelerator mass spectrometry (AMS) analysis of such samples. We have utilized established procedures (Vogel 1992) and developed new methods for handling various biological samples. We have included secondary standards of known isotope ratio for all assays. A method of determining maximum precision for each unknown sample value is also reported. The presented data are an update of the ongoing radiocarbon AMS biomedical program at Purdue University.