bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiocarbon Dating of Charred Residues on the Earliest Pottery in Japan
Authors: Nakamura Toshio , Taniguchi Yasuhiro , Tsuji Sei'ichiro , Oda Hirotaka
Published: July 2016

Recently, primitive-type pottery was discovered in the Russian Far East, China, and Japan. Radiocarbon ages of far earlier than 10,000 BP have been obtained, relating directly or indirectly to the pottery. As an example of these very old 14C ages for incipient pottery, we report here 14C ages of charred adhesions on five potsherds and three charred wood fragments that were collected with the archeological artifacts (stone tools from the Chojakubo Culture) in the loam layers at the Odai Yamamoto I site (41°03′44′′N, 140°33′20′′E) in Aomori prefecture, at the northern end of the Japanese main island. The carbonaceous remains on the surface of the potsherds could be ancient food residues or soot from fuel for cooking. These small carbon samples were dated at the Tandetron accelerator mass spectrometry (AMS) 14C dating facility at Nagoya University, as well as by Beta Analytic Co. Ltd. Except for two charred wood 14C dates, 7070 ± 40 and 7710 ± 40 BP, all five charred-residue samples and one wood charcoal sample gave older 14C ages of 12,680–13,780 BP, corresponding to the period of the Chojakubo Culture in Japan. This culture marks the beginning of the Jomon Culture, which is characterized by pottery usage and bow-and-arrow hunting.
Ultra-Microscale (5–25 μg C) Analysis of Individual Lipids by 14C AMS: Assessment and Correction for Sample Processing Blanks
Authors: Shah Sunita R , Pearson Ann
Published: July 2016

Measurements of the natural abundance of radiocarbon in biomarker molecules can be used to elucidate the biogeochemical roles of marine bacteria and archaea in the oceanic water column. However, the relatively low concentration of biomass, especially below the euphotic zone, inevitably results in small sample sizes for compound-specific analyses. In ultra-microscale Δ14C measurements, which we define as measurements on samples smaller than 25 μg C, the process of isolating pure compounds and preparing them for measurement adds significant background carbon. This additional blank carbon can contribute up to 40% of the total sample mass; therefore, it is necessary to quantify all components of the processing blank in order to make appropriate corrections. Complete propagation of error is critical in order to report the correct analytical uncertainty. The carbon blank is composed of at least 3 different sources: i) those that scale in proportion to the mass of the sample; ii) sources that contribute a constant mass of blank, e.g. closed-tube combustion; and iii) contaminants from vacuum lines and/or other aspects of sample handling that are difficult to quantify. We approached the problem of correcting for the total sample processing blank by deriving a 4-part isotopic mass balance based on separating the 3 exogenous components from the sample. Subsequently, we derived the appropriate equations for the full propagation of error associated with these corrections. Equations for these terms are presented. Full treatment of a set of raw data is demonstrated using compound-specific Δ14C data from the North Central Pacific water column.
The Marine ΔR for Nenumbo (Solomon Islands): A Case Study in Calculating Reservoir Offsets from Paired Sample Data
Authors: Jones Martin , Petchey Fiona , Green Roger , Sheppard Peter , Phelan Matthew
Published: July 2016

It is necessary to calculate location-specific marine ΔR values in order to calibrate marine samples using calibration curves such as those provided through the IntCal98 (Stuiver et al. 1998) data. Where known-age samples are available, this calculation is straightforward (i.e. Stuiver et al. 1986). In the case that a paired marine/terrestrial sample calculation is performed, however, the standard calculation (i.e. Stuiver and Braziunas 1993) requires that the samples are treated as relating to isochronous events. This may not be an appropriate assumption for many archaeological paired samples. In this paper, we present an approach to calculating marine ΔR values that does not require the dated events to be treated as isochronous. When archaeological evidence allows the dated events to be tightly temporally constrained, the approach presented here and that described by Stuiver and Braziunas (1993) give very similar results. However, where tight temporal constraints are less certain, the 2 approaches can give rise to differing results. The example analysis considered here shows that a ΔR of −81 ± 64 14C yr is appropriate for samples in the vicinity of Nenumbo (Reef Islands, southeast Solomon Islands) around the period 2000–3000 BP.
Performance Test of a New Graphite Target Production Facility in ATOMKI
Authors: Rinyu L , Futó I , Kiss Á Z , Molnár M , Svingor É , Quarta G , Calcagnile L
Published: July 2016

We present our new graphite target production system, developed in the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), for accelerator mass spectrometry (AMS) radiocarbon dating measurements. The system consists of a gas handling line and a graphite target production system. Results of AMS measurements, stable isotope mass spectrometry measurements, and gravimetric/pressure yield determinations have been used to find the proper conditions for the graphitization process. We have also investigated the 14C contamination and the memory effect of the system during the graphitization processes. This paper covers the details of these experiments and a discussion of the results.
AMS 14C Sample Preparation at the KCCAMS/UCI Facility: Status Report and Performance of Small Samples
Authors: Santos G M , Moore R B , Southon J R , Griffin S , Hinger E , Zhang D
Published: July 2016

We present an overview of accelerator mass spectrometry (AMS) radiocarbon sample preparation and measurements, describing the technical upgrades that now allow us to routinely obtain 0.2–0.3% precision for 1-mg carbon samples. A precision of ∼1% on samples with 100 μg of carbon can also be achieved. We have also developed graphitization techniques and AMS procedures for ultra-small samples (down to 0.002 mg of carbon). Detailed time series are presented for large and small aliquots of standards such as NIST OX-I and OX-II; FIRI-C and -D; IAEA-C6, -C7 and -C8; and 14C-free samples.
Cs Feed Tests and Emittance Measurements on a Modified MC-SNICS Ion Source for Radiocarbon AMS
Authors: Southon John , Santos Guaciara dos , Han Baoxi
Published: July 2016

We report on 2 recent developments in an ongoing program of characterizing and improving the National Electrostatics Corp. (NEC) MC-SNICS ion source at University of California (UC) Irvine's Keck AMS laboratory. First, we have investigated the possibility of modifying a large-body (134-sample) MC-SNICS to incorporate the UC Irvine Cs oven and vacuum-insulated Cs feed tube, which provide better confinement of Cs than the standard NEC setup. In our 40-sample source, the feed tube enters the source housing directly below the ionizer assembly. This area cannot be accessed for machining on the 134-sample source, but we have successfully tested a modified geometry where the delivery tube enters the body via the source end flange. Second, we recently installed a second beam profile monitor in the injection line of our spectrometer to allow us to make online emittance measurements. At full output (150 μA of C− at 55 keV), the emittance of our source at 8 kV sputtering voltage is approximately 40π mm mrad.
Robust Radiocarbon Dating of Wood Samples by High-Sensitivity Liquid Scintillation Spectroscopy in the 50–70 kyr Age Range
Authors: Hogg Alan G , Fifield L Keith , Palmer Jonathan G , Turney Chris S M , Galbraith Rex
Published: July 2016

Although high-sensitivity liquid scintillation (LS) spectroscopy is theoretically capable of producing finite radiocarbon ages in the 50,000- to 70,000-yr range, there is little evidence in the literature that meaningful dates in this time period have been obtained. The pressing need to undertake calibration beyond 26 kyr has resulted in the regular publication of 14C results in excess of 50 kyr, yet very little effort has been made to demonstrate their accuracy or precision. There is a paucity of systematic studies of the techniques required to produce reliable dates close to background and the methods needed to assess contamination from either in situ sources or laboratory handling and processing. We have studied the requirements for producing accurate and reliable dates beyond 50 kyr. Laboratory procedures include optimization of LS spectrometers to obtain low and stable non-14C background count rates, use of low-background counting vials, large benzene volumes, long counting times, and preconditioning of vacuum lines. We also discuss the need for multiple analyses of a suitable material containing no original 14C (background blank) and the application of an appropriate statistical model to compensate for variability in background contamination beyond counting statistics. Accurate and reproducible finite ages >60 kyr are indeed possible by high-sensitivity LS spectroscopy, but require corroborating background blank data to be defensible.
Towards a Radiocarbon Calibration for Oxygen Isotope Stage 3 Using New Zealand Kauri (Agathis Australis)
Authors: Turney Chris S M , Fifield L Keith , Palmer Jonathan G , Hogg Alan G , Baillie Mike G L , Galbraith Rex , Ogden John , Lorrey Andrew , Tims Stephen G
Published: July 2016

It is well known that radiocarbon years do not directly equate to calendar time. As a result, considerable effort has been devoted to generating a decadally resolved calibration curve for the Holocene and latter part of the last termination. A calibration curve that can be unambiguously attributed to changes in atmospheric 14C content has not, however, been generated beyond 26 kyr cal BP, despite the urgent need to rigorously test climatic, environmental, and archaeological models. Here, we discuss the potential of New Zealand kauri (Agathis australis) to define the structure of the 14C calibration curve using annually resolved tree rings and thereby provide an absolute measure of atmospheric 14C. We report bidecadally sampled 14C measurements obtained from a floating 1050-yr chronology, demonstrating repeatable 14C measurements near the present limits of the dating method. The results indicate that considerable scope exists for a high-resolution 14C calibration curve back through OIS-3 using subfossil wood from this source.
14C Ages of 43 Consecutive Single-Year Tree Rings Between 2710 and 2655 cal BP Using Accelerator Mass Spectrometry
Authors: Suzuki Kayo , Sakurai Hirohisa , Takahashi Yui , Gunji Shuichi , Tokanai Fuyuki , Matsuzaki Hiroyuki , Sunohara Yoko
Published: July 2016

We have measured the radiocarbon ages of 43 consecutive single-year tree rings using accelerator mass spectrometry (AMS) with a statistical accuracy of ∼2.3%. AMS 14C ages of the 36 viable samples are between 2708 and 2666 cal BP, a period in which the Δ14C of the IntCal04 curve (Reimer et al. 2004) shows an enhancement. The 14C ages of the samples are scattered with a Gaussian distribution around the interpolated IntCal04 calibration curve. The time profile of the deviations of the 36 14C ages from the interpolated IntCal04 calibration curve indicates a linear trend and a characteristic variability rather than a random fluctuation around the curve. The trend indicates a higher gradient than that of the interpolated IntCal04 calibration curve. The profile implies a periodic variation of approximately 11 yr and an amplitude of roughly 18 14C yr.
Dating of the Old Bridge in Mostar, Bosnia and Herzegovina
Authors: Obelić Bogomil , Bronić Ines Krajcar , Barešić Jadranka , Peković Željko , Milošević Ante
Published: July 2016

The famous single-arch stone bridge over the Neretva River in Mostar, Bosnia and Herzegovina, was built in 1557–1566 by the order of Ottoman Sultan Süleyman the Magnificent. During the reconstruction of the Old Bridge, which was destroyed during the war in 1993, remnants of 2 older wooden bridges were found at the same location. Six wood and 2 charcoal samples were dated using the radiocarbon method. Wood samples with visible tree rings were taken for dendrochronological dating. The results point to several periods of construction and repairs to the bridge and the towers at each end, spanning from the 12th to 18th century. Calibrated 14C and dendrochronological ages were in good agreement.
The Early Medieval Origin of Perth, Scotland
Authors: Hall D W , Cook G T , Hall M A , Muir G K P , Hamilton D , Scott E M
Published: July 2016

The radiocarbon results (and Bayesian modeling) of 15 samples of carbonized food residues removed from the external surface of rim sherds of cooking pots indicate that shellyware pottery first appeared in Perth, Scotland, around cal AD 910–1020 (95% probability) and that it had disappeared by cal AD 1020–1140 (95% probability). Previously, it had been suggested that this pottery could not date to before AD 1150. These data, together with 14C analyses carried out on leather artifacts and a sample of wattle from a ditch lining, also demonstrate that there was occupation in Perth about 100 yr or more prior to the granting of royal burgh status to Perth in the 1120s.
Radiocarbon Dating of the Crannogs of Loch Tay, Perthshire (Scotland)
Authors: Dixon T N , Cook G T , Andrian B , Garety L S , Russell N , Menard T
Published: July 2016

Crannogs are ancient artificial islands found in Scotland and Ireland, which typically had some sort of dwelling place constructed on them that served variously as farmers' homesteads, status symbols, refuges in times of trouble, hunting and fishing stations, etc. Substantial research has been carried out for similar sites in mainland Europe, which has demonstrated that they were lakeside settlements, mostly dating to the Neolithic period and not built over open water. In contrast, the Scottish and Irish sites were built in open water, clearly separate from the shore. In Perthshire, some prehistoric crannogs were originally timber-built roundhouses supported on piles or stilts driven into the loch bed. Today, these crannogs appear as tree-covered islands or remain hidden as submerged stony mounds. Until recently, there were few radiocarbon dates for these structures and so the sites appeared as a homogeneous group. Not only did this make it impossible to examine them in sub-groupings but it also inhibited research, as they did not fit into known periods or architecturally distinct sub-groups, except that they were surrounded by water. Recent work in Loch Tay has resulted in14C dating of the timber piles from 13 of the 18 crannogs in the loch, allowing them to be fitted into different classes. A major group was constructed in the Early Iron Age around 400–800 BC, with smaller groups constructed around 200–300 BC and 0 BC/AD. There is also evidence of repair/reoccupation of some of these crannogs in the 6th–9th centuries AD. A number of the sites were also known to be inhabited into the recent past, with one, Priory Island, occupied until the 17th century. The dates of construction also raise important issues relating to the loch-level changes that have taken place. The14C results will be discussed in relation to the periods of origin and habitation of the crannogs.
Radiocarbon Date Frequency as an Index of Intensity of Paleolithic Occupation of Siberia: Did Humans React Predictably to Climate Oscillations?
Authors: Fiedel Stuart J , Kuzmin Yaroslav V
Published: July 2016

Upper Paleolithic humans occupied southern Siberia by about 43,000–38,000 BP (14C yr), and afterward continued to live there despite the very cold climate. If climatic conditions limited expansion of the colonizing population in northern Siberia, the Paleolithic ecumene should have contracted during the coldest episodes within the last 40,000 yr, and fewer 14C-dated sites should be known from those periods. In fact, the human population seems to have remained stable or even expanded during cold periods. Comparison of calibrated 14C dates for Siberian occupations with Greenland ice cores fails to demonstrate a simple correlation between climatic fluctuations and the dynamics of human colonization and persistence in Siberia between about 36,000 and 12,000 BP. Cold climate does not appear to have posed any significant challenge to humans in Siberia in the Late Pleistocene, and a supposed Last Glacial Maximum “hiatus” in population dynamics seems illusory.
Seasonal Variations in Peruvian Marine Reservoir Age from Pre-Bomb Argopecten Purpuratus Shell Carbonate
Authors: Jones Kevin B , Hodgins Gregory W L , Dettman David L , Andrus C Fred T , Nelson April , Etayo-Cadavid Miguel F
Published: July 2016

Marine upwelling along coastal Peru can be intense and variable, making radiocarbon dating marine and coastal systems complex. Historical and proxy records of upwelling along coastal Peru are few, and long-lived species such as corals do not grow in the cold coastal waters. Mollusk shell carbonate, however, can record both the magnitude of the local marine reservoir correction, ΔR, and of seasonal oscillations in the ventilation age of coastal waters. If large, these seasonal oscillations would complicate radiocarbon dating of marine organisms. To examine this possibility, we sampled for δ13C, δ18O, and 14C content a set of pre-bomb Argopecten purpuratus shells collected from coastal Peru during 1908 and 1926. Intrashell variations of up to 216 14C yr were noted, but these were not consistently correlated with seasonal changes in δ18O or δ13C. Only an 11 yr difference was observed in the weighted average ΔR of Callao Bay shells collected during normal (1908) and El Niño (1926) years. Despite the intrashell 14C variation noted, weighted average ΔR values from all 3 sample sites and from normal and El Niño years all overlap at 1 σ. We report ΔR values of 183 ± 18 and 194 ± 23 yr from Callao Bay (12°4′S), 165 ± 24 yr from Salaverry (8°14′S), and 189 ± 23 yr from Sechura Bay (5°45′S).
Reservoirs and Radiocarbon:14C Dating Problems in Mývatnssveit, Northern Iceland
Authors: Ascough Philippa L , Cook Gordon T , Church Mike J , Dugmore Andrew J , McGovern Thomas H , Dunbar Elaine , Einarsson árni , Frioriksson Adolf , Gestsdóttir Hildur
Published: July 2016

This paper examines 2 potential sources of the radiocarbon offset between human and terrestrial mammal (horse) bones recovered from Norse (∼AD 870–1000) pagan graves in Mývatnssveit, north Iceland. These are the marine and freshwater14C reservoir effects that may be incorporated into human bones from dietary sources. The size of the marine14C reservoir effect (MRE) during the Norse period was investigated by measurement of multiple paired samples (terrestrial mammal and marine mollusk shell) at 2 archaeological sites in Mývatnssveit and 1 site on the north Icelandic coast. These produced 3 new δR values for the north coast of Iceland, indicating a δR of 106 ± 1014C yr at AD 868–985, and of 144 ± 2814C yr at AD 1280–1400. These values are statistically comparable and give an overall weighted mean δR of 111 ± 1014C yr.

The freshwater reservoir effect was similarly quantified using freshwater fish bones from a site in Mývatnssveit. These show an offset of between 1285 and 183014C yr, where the fish are depleted in14C relative to the terrestrial mammals. This is attributed to the input of geothermally derived CO2into the groundwater and subsequently into Lake Mývatn. We conclude the following: i) some of the Norse inhabitants of Mývatnssveit incorporated non-terrestrial resources into their diet that may be identified from the stable isotope composition of their bone collagen; ii) the MRE off the north Icelandic coast during the Norse period fits a spatial gradient of wider North Atlantic MRE values with increasing values to the northwest; and iii) it is important to consider the effect that geothermal activity could have on the14C activity of samples influenced by groundwater at Icelandic archaeological sites.
Do Riparian Plants Fix CO2 Lost by Evasion from Surface Waters? An Investigation Using Carbon Isotopes
Authors: Garnett M H , Billett M F
Published: July 2016

Rivers and streams in many parts of the world contain high concentrations of dissolved carbon dioxide, which is lost to the atmosphere by evasion (outgassing). Recent methodological advances now enable the carbon isotopic composition of this evaded CO2 to be measured directly, with early results from peatland streams showing it to be depleted in 13C relative to the atmosphere. The first direct measurements of the radiocarbon age of evaded CO2 for a stream draining a peatland site in the United Kingdom covered a large range, ranging from modern to >1400 yr BP. We investigated whether a proportion of the carbon fixed by plants growing adjacent to the stream was derived from evasion; this would have implications for the cycling of carbon in such streams, and lead to riparian plants having older, rather than contemporary, 14C ages.

13C analysis of riparian plants at the site suggested that up to 20% of the carbon they fixed was derived from evasion. Although the 14C content of the same samples suggested a similar proportion of plant carbon was derived from evaded CO2, the uncertainty in these estimates was greater. Fixation of evaded CO2 was greatest in plants growing within 1 m of the stream. Although the results for this site suggest a small amount of CO2 lost by evasion from the stream surface is incorporated in plant material, it may be a more important factor at other sites characterized by higher evasion rates, lower wind speeds, and different stream bank morphology.
Results of Radiocarbon Analysis of Upper Weichselian Loess Sequences from Hungary
Authors: Sümegi Pal , Molnár Mihály , Svingor éva , Szántó Zsuzsanna , Hum László , Gulyás Sándor
Published: July 2016

Approximately 10% of Hungary is covered by dust sequences of the Quaternary period. Samples have been taken from more than 50 outcrops and boreholes during fieldwork in the past 20 yr. Some 81 bulk samples taken from 27 profiles of the Hungarian loess regions have been analyzed for radiocarbon. Based on the 14C results, loess layers that accumulated between 33,000 and 12,000 BP were selected for further investigation. The sedimentation rates of the 27 loess profiles suggest periods of slow and quick dust accumulation in the Carpathian Basin during the Upper Weichselian period. It seems to us that some soil development and intense weathering periods interrupted the loess development during the Upper Weichselian in Hungary. According to the 14C dates, the estimated average rate of sedimentation was 0.31 mm/yr in both the northern and southern parts of the Carpathian Basin between 33,000 and 12,000 BP.
Using a Soil Chronosequence to Identify Soil Fractions for Understanding and Modeling Soil Carbon Dynamics in New Zealand
Authors: Prior Christine A , Baisden W Troy , Bruhn Frank , Neff Jason C
Published: July 2016

We are developing practical methodologies to characterize pool sizes and residence times for fractions of soil organic matter (SOM) using radiocarbon, with a particular focus on SOM in New Zealand pasture soils that responds to global change on decadal timescales. As single mean residence times for the entire SOM pool can be misleading or uninterpretable, we focus on the use of samples collected about 7 and 40 yr after the bomb14C spike to separate SOM into at least 2 pools. These results from a box model methodology yield sensible estimates of the proportion of “passive” SOM, and the residence time of the dominant pool with approximately decadal residence times. These results are supported by chemical analysis. Approximately 45-yr residence times of light-fraction SOM in a relatively infertile soil contrast with ∼16-yr residence times in a more fertile soil, and correspond to large differences in the proportion of lignin- and polysaccharide-derived SOM in these soils measured using pyrolysis-GC/MS. To achieve greater detail and assess the degree to which “active” SOM with annual turnover rates may bias results from the simple model, we use density as a means of isolating SOM with different degrees of mineral association. Initial results from grazed pasture soils sampled in 2003–4 emphasize that isolating non-mineral-associated light fractions can improve understanding, but may be less important than identifying fractions associated with unique mineralogy. In this soil, a fraction with density ≥2.55 g/mL shows much larger proportions of passive SOM than other fractions.
Radiocarbon and Blue Optically Stimulated Luminescence Chronologies of the Oitavos Consolidated Dune (Western Portugal)
Authors: Prudêncio M I , Marques R , Rebelo L , Cook G T , Cardoso G O , Naysmith P , Freeman S P H T , Franco D , Brito P , Dias M I
Published: July 2016

The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (∼20,000 cal BP) than the OSL age measurement (∼15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ∼35,000 yr and ∼34,000 yr, respectively. Rare-earth element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (∼15,000 yr) is consistent with the age for the base of the dune (∼14,500 yr). The younger OSL age for the top of the dune (∼12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation.
Further Radiocarbon Dates for the Upper Paleolithic of El Mirón Cave (Ramales De La Victoria, Cantabria, Spain)
Authors: Straus Lawrence Guy , Morales Manuel R González
Published: July 2016

This article expands the date list from the Stone Age cave site of El Mirón in the Cantabrian Cordillera of northern Spain to a total of 62 radiocarbon determinations, one of the longest series from a single prehistoric site in Iberia. All the assays (accelerator mass spectrometry [AMS] and conventional, run on charcoal and bone collagen) were done by a single laboratory (Geochron, GX). The 11 new dates confirm 1) the late spread of Neolithic economy and technology into the Atlantic environment of Cantabrian Spain by about 4500 cal BC; 2) the horizontally extensive, but not intensive, use of the whole cave vestibule by Upper Magdalenian foragers about 12,000–14,000 cal BC; 3) extensive and very intensive, repeated occupations of the cave during the Middle and Lower Cantabrian Magdalenian about 14,200–17,000 cal BC; and 4) a long, gradual technological transition from the Solutrean to the Archaic Magdalenian between about 20,000–17,000 cal BC. El Mirón joins a list of culturally very rich, frequently occupied, Lower Magdalenian residential hub sites—most of the rest of which (including Altamira) are located in the coastal lowlands of Cantabria—which have yielded distinctive red deer scapulae that are decorated with striated engraved images of game animals (mainly red deer hinds), now most precisely dated at El Mirón between 16,200–17,200 cal BC.
Radiocarbon Dating of Several Ancient Jewish Oil Lamps from Rome
Authors: Rutgers Leonard V , von der Borg Klaas , de Jong Arie F M
Published: July 2016

In this paper, we discuss how the radiocarbon dating of soot on oil lamps can help determine the chronology of the Jewish catacombs of Rome. We also explore the ramifications of our work for the typological study of Roman period terracotta lamps.
Radiocarbon Analysis Confirms the Annual Nature of Sagebrush Growth Rings
Authors: Biondi Franco , Strachan Scotty D J , Mensing Scott , Piovesan Gianluca
Published: July 2016

In the Great Basin of North America, big sagebrush (Artemisia tridentata Nutt.) growth rings can be used to reconstruct environmental changes with annual resolution in areas where there is otherwise little such information available. We tested the annual nature of big sagebrush wood layers using accelerator mass spectrometry (AMS) radiocarbon dating. Four cross-sections from 3 sagebrush plants were collected near Ely, Nevada, USA, and analyzed using dendrochronological methods. Ten 14C measurements were then used to trace the location of the 1963–64 “bomb spike.” Although the number of rings on each section did not exceed 60, crossdating was possible within a section and between sections. Years assigned to individual wood layers by means of crossdating aligned with their expected 14C values, matching the location of the 14C peak. This result confirmed the annual nature of growth rings formed by big sagebrush, and will facilitate the development of spatially explicit, well-replicated proxy records of environmental change, such as wildfire regimes, in Great Basin valleys.
A Tentative Determination of Upwelling Influence on the Paleo-Surficial Marine Water Reservoir Effect in Southeastern Brazil
Authors: Angulo Rodolfo J , Reimer Paula J , de Souza Maria C , Scheel-Ybert Rita , Tenório Maria C , Disaró Sibelle T , Gaspar Maria D
Published: July 2016

Previous work has suggested that seasonal and interannual upwelling of deep, cold, radiocarbon-depleted waters from the South Atlantic has caused variations in the reservoir effect (R) through time along the southern coast of Brazil. This work aims to examine the possible upwelling influence on the paleoreservoir age of Brazilian surficial coastal waters based on paired terrestrial/marine samples obtained from archaeological remains. On the Brazilian coast, there are hundreds of shell middens built up by an ancient culture that lived between 6500 to 1500 yr ago, but there are few shell middens located on open-coast sites with a known upwelling influence. Three archaeological sites located in a large headland in Arraial do Cabo and Una de Cabo Frio on the southeastern coast of Brazil, with open-ocean conditions and a well-known strong and large upwelling of the Malvinas/Falkland current, were chosen for this study. The 14C age differences between carbonized seed and marine samples varied from 281 ± 44 to 1083 ± 51 14C yr. There are also significant age differences between carbonized seed samples (977 14C yr) and marine samples (200 and 228 14C yr) from the same archaeological layer that cannot be explained by a reservoir effect or an old-wood effect for charcoal. Therefore, the present data from the southeastern Brazilian coast are inconclusive for identifying an upwelling effect on R. To do so, it would be necessary to more precisely define the present–pre-bomb R in upwelling regions, and to analyze paired marine/terrestrial samples that are contemporaneous beyond doubt.
The Freshwater Reservoir and Radiocarbon Dates on Cooking Residues: Old Apparent Ages or a Single Outlier? Comments on Fischer and Heinemeier (2003)
Authors: Hart John P , Lovis William A
Published: July 2016

Fischer and Heinemeier (2003) present a hypothesis that the freshwater reservoir effect produces old apparent ages for radiocarbon dates run on charred cooking residues in regions where fossil carbon is present in groundwater. The hypothesis is based in part on their analysis of dates on charred cooking residues from 3 inland archaeological sites in Denmark in relation to contextual dates from those sites on other materials. A critical assessment of the dates from these sites suggests that rather than a pattern of old apparent dates, there is a single outlying date—not sufficient evidence on which to build a case for the freshwater reservoir effect.
Drastic Increase of Background in the Gliwice Radiocarbon Laboratory During Late April, 1986, and its Time Changes
Authors: Pazdur Mieczysław F , Zastawny Andrzej
Published: July 2016

Preliminary observations of changes of the background of three proportional counters during May and June, 1986, are presented. Some isotopes contributing to the rise of background were identified on the basis of their half-life determinations.
An Assessment of Laboratory Contamination at the Isotrace Radiocarbon Facility
Authors: Gurfinkel D M
Published: July 2016

An assessment of the contamination contribution of various sample preparation procedures used at the Isotrace Radiocarbon Facility, University of Toronto, is described. Samples of geologic material, millions of years old, or samples derived therefrom, were tested because these would presumably contain only dead carbon. Results showed, however, that 14C contamination could be detected in several samples, complicating the contamination assessment. Best estimates of the contamination contribution from sample preparation were reported as: cracking: <0.17% modern, acetylene synthesis: <0.25% modern, combustion: <0.39% modern, and handling: <0.54% modern. These estimates were reported as upper limits because they likely represented 14C derived from two sources: sample preparation and the sample itself.
Measurement of Small Volume Oceanic 14C Samples by Accelerator Mass Spectrometry
Authors: Schlosser Peter , Pfleiderer Christoph , Kromer Bernd , Levin Ingeborg , Münnich K O , Bonani Georges , Suter Martin , Wölfli Willy
Published: July 2016

A technique for 14C measurement of small volume (0.5L) oceanic water samples by Accelerator Mass Spectrometry (AMS) is described. Samples were taken from a CTD/rosette system used for standard hydrographic work. After CO2 extraction and target preparation, the samples were measured at the Zürich tandem accelerator facility. On the basis of 14C data from samples collected on a station in the northern Weddell Sea, the precision of the measurements is estimated to ca ±8‰. The error in the present AMS results is dominated by the statistical error in 14C detection. From results of duplicate targets, it is concluded that a precision of ±5° can be reached. The 14C data are discussed in relation to the Weddell Sea hydrography.
US Geological Survey, Denver, Colorado Radiocarbon Dates V
Authors: Yang I C
Published: July 2016

This list contains the results of measurements of 172 radiocarbon samples made between January 1983 and December 1985. An additional 152 samples were measured, but these were submitted without detailed information, such as sample location and sampling depth; therefore, they were excluded from the list.
Small Sample 14C Dating by Liquid Scintillation Spectrometry
Authors: Polach Henry , Kaihola Lauri , Robertson Steve , Haas Herbert
Published: July 2016

Small sample 14C dating is tested using conventional as well as high-resolution low-level liquid scintillation (LS) spectrometers. Contrasted are the results obtained dating ∼25, 125 and 250mg of elemental carbon in standard size counting vials (3mL) and 0.3mL teflon and quartz vials. It is demonstrated that the improved performance of the 0.3mL counting vials enables just adequate resolution of 25mg and very good resolution of 100mg carbon samples both at Modern and Old age limits when the determination is made in a high-resolution low-level LS spectrometer.
Radiocarbon Dates from the Mussau Islands and the Lapita Colonization of the Southwestern Pacific
Authors: Kirch P V , Hunt T L
Published: July 2016

Three decades of archaeological excavations in Melanesia and Western Polynesia have led to a consensus among Oceanic prehistorians that the initial human colonization of the southwestern Pacific (east of the Solomons) was effected by populations of the Lapita Cultural Complex (Green, 1979; Kirch, 1982, 1984; Allen, 1984; Spriggs, 1984). Although the western Melanesian islands of New Guinea, the Bismarck Archipelago, and possibly the Solomon Islands were settled in the late Pleistocene by small hunter-gatherer populations (Downie & White, 1979; Specht, Lilley & Normu, 1981; Groubeet al, 1986), discovery and occupation by humans of the more remote island chains to the east required sophisticated voyaging and colonization strategies. That the Austronesian-speaking Lapita people possessed long-distance voyaging craft is suggested both by lexical reconstructions, and by the archaeological evidence of long-distance transport of obsidian and other exotic materials over distances of up to 3700km (Ambrose & Green, 1972; Best, 1987). Lapita sites are marked by a distinctive complex of dentate-stamped earthenware ceramics, and associated shell, bone, and stone artifacts. Sites yielding such assemblages have been recorded between the Bismarck Archipelago in the west, through Melanesia, and as far east as Samoa and Tonga, a straight-line distance of ca 4500km.
Harwell Radiocarbon Measurements VII
Authors: Walker A J , Keyzor R S , Otlet R L
Published: July 2016

The results presented in this list are mostly from our earlier years of operation, the most recent of which were measured in 1984. It is the second of a series of special lists being prepared hopefully to clear the backlog of unpublished dates of this laboratory. All samples are of archaeological origin from the United Kingdom; most have originated from “rescue” type excavations and all were sponsored by the Ancient Monuments Laboratory of the Historic Buildings and Monuments Commission.
University of Wisconsin Radiocarbon Dates XXV
Authors: Steventon Raymond L , Kutzbach John E
Published: July 2016

Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists. Except as otherwise indicated, wood, charcoal, and peat samples are pretreated with dilute NaOH—NA4P2O7 and dilute H3PO4 before conversion to the counting gas methane; when noted, marls and lake cores are treated with acid only. Very calcareous materials are treated with HCL instead of H3PO4. Pretreatment of bone varies with the condition of the bone sample; solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCL for 15 minutes, then dilute NaOH—Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted according to Longin (1971). Charred bone is treated with dilute HCL, NaOH—Na4P2O7, and then dilute HCL again.
A Standard Sample of 14C-Specific β Activity
Authors: Veksler Vitali , Sulerzhitsky Leopold , Arslanov Hikmat , Punning Jaan-Mati
Published: July 2016

A standard sample (SS) of 14C-specific β activity has been created based on benzene containing radioactive carbon diluted with “dead” benzene.
Krakow Radiocarbon Measurements I
Authors: Kuc Tadeusz , Lewandowska Bogusława , Krapiec Marek
Published: July 2016

The Krakow Radiocarbon Laboratory is part of the Environmental Physics Department headed by T Florkowski and belongs to the Institute of Physics and Nuclear Techniques, The Academy of Mining and Metallurgy. A 3H and 14C laboratory was built primarily for the assessment of natural radioactivity in groundwater. In 1982, 14C preparation facilities were extended to include a combustion system for organic samples. The 14C measurement method is liquid scintillation counting on synthesized benzene in an LSC spectrometer TRI-CARB model 3320 (Packard International).
From the Editor
Authors: Long Austin
Published: July 2016

A few of our colleagues, upon receiving a radiocarbon date younger than they expected, have wondered if X-rays in airport security devices might have increased their 14C content. Unfortunately for them, our colleagues have been forced to find alternate explanations for the uncooperative dates. Airport X-rays simply cannot produce 14C. However, a new security technology is almost ready for installation at Kennedy Airport for some international flights, and, according to the Wall Street Journal, 100 additional units are planned for other high-risk airports. The new device will detect high concentrations of nitrogen (a component in explosives) by thermal neutron activation (TNA). Since TNA on a global scale is the process by which nature produces virtually all 14C in the atmosphere, some 14C must be produced in high-nitrogen materials, such as bones, as they pass through a neutron activation airport security device. The question important to the radiocarbon dating community is how much effect can the 14C thus produced have on the 14C date?
Problems Associated with the Use of Coal As a Source of14C-Free Background Material
Authors: Lowe David C
Published: July 2016

Many14C dating laboratories have established that coal samples exhibit a finite14C age, apparently caused by contamination of the specimens before any laboratory preparation is undertaken. In this work, the possibility that the contamination is due to microbial and fungal activity in the coal substrate is considered and some suggestions are made for alternative sources of background test materials for14C dating laboratories. Initial results indicate that geologically formed graphites contain little14C and are likely to be good background test materials, especially in14C AMS laboratories.
Institut Royal du Patrimoine Artistique Radiocarbon Dates XIII
Authors: Dauchot-Dehon Michele , Strydonck Mark Van
Published: July 2016

This list contains the results of14C determinations obtained at the laboratory in 1986 and 1987. δ13C was measured by the British Museum Research Laboratory or the Free University of Brussels:*δ13C is estimated (Stuiver & Polach, 1977).
The Radiocarbon Chronology of El Mirón Cave (Cantabria, Spain): New Dates for the Initial Magdalenian Occupations
Authors: Straus Lawrence Guy , Morales Manuel R González
Published: July 2016

Three additional radiocarbon assays were run on samples from 3 levels lying below the classic (±15,500 BP) Lower Cantabrian Magdalenian horizon in the outer vestibule excavation area of El Mirón Cave in the Cantabrian Cordillera of northern Spain. Although the central tendencies of the new dates are out of stratigraphic order, they are consonant with the post-Solutrean, Initial Magdalenian period both in El Mirón and in the Cantabrian region, indicating a technological transition in preferred weaponry from foliate and shouldered points to microliths and antler sagaies between about 17,000–16,000 BP (uncalibrated), during the early part of the Oldest Dryas pollen zone. Now with 65 14C dates, El Mirón is one of the most thoroughly dated prehistoric sites in western Europe. The until-now poorly dated, but very distinctive Initial Cantabrian Magdalenian lithic artifact assemblages are briefly summarized.
Successful AMS 14C Dating of Non-Hydraulic Lime Mortars from the Medieval Churches of the Åland Islands, Finland
Authors: Heinemeier Jan , Ringbom Åsa , Lindroos Alf , Sveinbjörnsdóttir Árný E
Published: July 2016

Fifteen years of research on accelerator mass spectrometry (AMS) radiocarbon dating of non-hydraulic mortar has now led to the establishment of a chronology for the medieval stone churches of the Åland Islands (Finland), where no contemporary written records could shed light on the first building phases. In contrast to other material for dating, well-preserved mortar is abundantly available from every building stage.

We have gathered experience from AMS dating of 150 Åland mortar samples. Approximately half of them have age control from dendrochronology or from 14C analysis of wooden fragments in direct contact with the mortar. Of the samples with age control, 95% of the results agree with the age of the wood. The age control from dendrochronology, petrologic microscopy, chemical testing of the mortars, and mathematical modeling of their behavior during dissolution in acid have helped us to define criteria of reliability to interpret the 14C results when mortar dating is the only possibility to constrain the buildings in time. With these criteria, 80% of all samples reached conclusive results, and we have thus far been able to establish the chronology of 12 out of the 14 churches and chapels, while 2 still require complementary analyses.
A High-Performance 14C Accelerator Mass Spectrometry System
Authors: Roberts M L , Burton J R , Elder K L , Longworth B E , McIntyre C P , Reden K F von , Han B X , Rosenheim B E , Jenkins W J , Galutschek E , McNichol A P
Published: July 2016

A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14C. Details and performance of the new system are presented.
Are Compact AMS Facilities a Competitive Alternative to Larger Tandem Accelerators?
Authors: Suter M , Müller A M , Alfimov V , Christl M , Schulze-König T , Kubik P W , Synal H-A , Vockenhuber C , Wacker L
Published: July 2016

In the last decade, small and compact accelerator mass spectrometry (AMS) systems became available operating at terminal voltages of 1 MV and below. This new category of instruments has become competitive for radiocarbon detection to larger tandem accelerators and many of these instruments are successfully used for 14C dating or biomedical applications. The AMS group at ETH Zurich has demonstrated that small instruments can be built, which allow measurements also of other radionuclides such as 10Be, 26Al, 129I, and the actinides. 41Ca measurements can be performed with sufficient sensitivity for biomedical applications. A summary of recent developments made at the 500kV Pelletron in Zurich is given and its performance is compared with that of a commercial compact instrument from the company High Voltage Engineering Europe (HVEE) in Amersfoort, the Netherlands, operating at 1MV at CNA in Seville, Spain, as well as with that of larger AMS facilities. It turns out that the ion optics, stripper design, and the detection system are critical for the performance.
New Dating Evidence for North Sea Trade Between England, Scotland, and Norway in the 11th Century AD
Authors: Hall D W , Cook G T , Hamilton W D
Published: July 2016

This study follows on from previous research at Perth, Scotland, in which we dated carbonized food residues removed from the external surface of rim sherds of cooking pots of London Sandy Shellyware pottery (Museum of London Pottery Fabric Code SSW). The 15 residues that were dated produced14C ages between 910 ± 35 and 1085 ± 40 BP. We have now carried out radiocarbon measurements on similar residues from the same fabric obtained from the Billingsgate excavations in London and the Bryggen excavations in Bergen, Norway. The London and Bergen measurements gave age ranges of 905 ± 35 to 1115 ± 35 BP and 920 ± 35 to 1055 ± 35 BP, respectively, both very similar to the Perth age range. The measurements at each site are in agreement with our Bayesian model assumption that they belong to a single phase of activity. The model estimates the introduction of London Sandy Shellyware in London tocal AD 820–1020,in Perth tocal AD 930–1020,and in Bergen tocal AD 980–1030(95% probability). Further modeling predicts that it fell out of use in the reverse order.