bluuebunny/crossref_metadata_2025 huggingface dataset:
A Revised Late Holocene Culture History for Moloka'i Island, Hawai'i
Authors: McCoy Mark D
Published: July 2016

Building directly upon a previous summary of 45 dates (Weisler 1989), this paper presents radiocarbon age determinations for 175 samples from archaeological and natural contexts and a revised culture history of Moloka'i Island, Hawai'i (cal AD 800 and 1795). Significant culture historical trends include an early settlement pattern apparently generalized with respect to ecozone; a remarkably long initial period of marine and endemic bird exploitation; strong material evidence for the concurrent intensification of subsistence economies, population increase, and the structuring of the social landscape through ritual; and links between island politics as described in oral traditions and site construction. Moreover, these results support a late chronology for the colonization of Hawai'i and demonstrate the value of spatial technology for building large chronometric databases.
Seoul National University Accelerator Mass Spectrometry (SNU-AMS) Radiocarbon Date List III
Authors: Youn M , Song Y M , Kang J , Kim J C , Cheoun M K
Published: July 2016

The accelerator mass spectrometry (AMS) facility at Seoul National University (SNU-AMS) was accepted in December 1998 and results reported first at the Vienna AMS conference in October 1999 and at the 17th Radiocarbon Conference in Israel, June 2000. At the Vienna conference, we reported our accelerator system and sample preparation systems (Kim et al. 2000). Recent developments of the AMS facility have been regularly reported at AMS conferences (Kim et al. 2001, 2004, 2007). Meanwhile, about 1000 unknown archaeological, geological, and environmental samples have been measured every year. In this report, the archaeological and geological data carried out in 2001 are presented in terms of years BP (before present, AD 1950), following the SNU-AMS date lists I and II published in Radiocarbon (Kim et al. 2006a,b).
Seoul National University Accelerator Mass Spectrometry (SNU-AMS) Radiocarbon Date List IV
Authors: Youn M , Song Y M , Kang J , Kim J C , Cheoun M K
Published: July 2016

The accelerator mass spectrometry (AMS) facility at Seoul National University (SNU-AMS) was accepted in December 1998 and results reported first at the Vienna AMS conference in October 1999 and at the 17th Radiocarbon Conference in Israel, June 2000. At the Vienna conference, we reported our accelerator system and sample preparation systems (Kim et al. 2000). Recent developments of the AMS facility have been regularly reported at AMS conferences (Kim et al. 2001, 2004, 2007). Meanwhile, about 1000 unknown archaeological, geological, and environmental samples have been measured every year. In this report, the archaeological and geological data carried out in 2002 are presented in terms of years BP (before present, AD 1950), following the SNU-AMS date lists I and II published in Radiocarbon (Kim et al. 2006a,b).
Extended Radiocarbon Calibration in the Anglo-Saxon Period, AD 395–485 and AD 735–805
Authors: McCormac F G , Bayliss A , Brown D M , Reimer P J , Thompson M M
Published: July 2016

Radiocarbon dating has been used infrequently as a chronological tool for research in Anglo-Saxon archaeology. Primarily, this is because the uncertainty of calibrated dates provides little advantage over traditional archaeological dating in this period. Recent advances in Bayesian methodology in conjunction with high-precision 14C dating have, however, created the possibility of both testing and refining the established Anglo-Saxon chronologies based on typology of artifacts. The calibration process within such a confined age range, however, relies heavily on the structural accuracy of the calibration curve. We have previously reported decadal measurements on a section of the Irish oak chronology for the period AD 495–725 (McCormac et al. 2004). In this paper, we present decadal measurements for the periods AD 395–485 and AD 735–805, which extends the original calibration set.
Zinc Reduction as an Alternative Method for AMS Radiocarbon Dating: Process Optimization at Circe
Authors: Marzaioli F , Borriello G , Passariello I , Lubritto C , Cesare N De , D'Onofrio A , Terrasi F
Published: July 2016

The pretreatment of samples for radiocarbon measurements, transforming a variety of materials into graphite solid targets, represents a critical point in the accelerator mass spectrometry (AMS) procedure. We describe the new, state-of-the-art CIRCE AMS preparation laboratory, particularly the setup and optimization of an alternative method, the zinc reduction method, for graphite target production, compared to the more common hydrogen reduction method. Measured 14C values on standard and blank samples reduced via zinc reaction revealed mean background levels, accuracy, and sensitivity comparable to those obtained by our conventional hydrogen reaction lines. Zinc line reduction at the CIRCE laboratory represents an effective and powerful alternative to the conventional hydrogen reduction, ensuring higher sample throughput with lower costs at a comparable performance level.
Scintillation Counter Performance at the SMU Radiocarbon Laboratory
Authors: Devine James M , Haas Herbert
Published: July 2016

Results are presented of a study of counter performance and vial characteristics for three liquid scintillation counters used at the SMU Radiocarbon Laboratory: the Intertechnique LS20, Packard Tri-Carb 460C, and LKB Wallac Rack Beta 1217. Modifications to photomultiplier tube high voltage, pre-amplifier gain, energy window settings, counting vial design, and sample holder design have resulted in reduced background, higher counting efficiency, and greater long-term stability for the Intertechnique and Packard counters. Square quartz counting vials are used in the Intertechnique and Packard counters with excellent results. Use of Teflon vials in the LKB counter requires careful cleaning procedures and long counting times.
Harwell Radiocarbon Measurements V
Authors: Walker A J , Keyzor R S , Otlet R L
Published: July 2016

The results presented in this list include some recently measured samples (1984) but mostly ones from our earlier years of operation which had not been previously published in RADIOCARBON. It is the first of a number of special lists prepared over the last year so that the backlog of unpublished dates of this laboratory will be cleared. The samples are all archaeologic from the United Kingdom most of which have originated from “rescue”-type excavations.
Rehovot Radiocarbon Measurements III
Authors: Carmi Israel
Published: July 2016

This list contains results obtained between 1981 and 1985. Since the first description of the laboratory (Carmi, Noter & Schlesinger, 1971) the following changes were made. Two proportional counters are now used: 1) 0.5L volume, 0.865 ± 0.023 cpm background, 12.830 ± .134 cpm NBS oxalic acid standard (old); 2) 0.25L volume, 0.484 ± 0.023 cpm background, 6.185 ± .123 cpm NBS oxalic acid standard (old). The passive shield has been increased by 2cm of mercury next to the counters. For anticoincidence, a modular, hand-made gas counter is used. The laboratory was transferred to the ground floor of a 7-storey building. Data acquisition and processing are done with a sealer/buffer built at the institute and an IBM PC computer. Samples are filled into the counters and counted for ca 1000min at least twice. The sample preparation method and counter filling pressure have not been changed.
University of Lund Radiocarbon Dates XX
Authors: Håkansson Sören
Published: July 2016

Most of the 14C measurements reported here were made between October 1985 and October 1986. Equipment, measurement, and treatment of samples are as reported previously (R, 1968, v 10, p 36–37; 1976, v 18, p 290; 1980, v 22, p 1045; 1986, v 28, no. 3, p 1111).
University of Granada Radiocarbon Dates IV
Authors: Gonzalez-Gomez Cecilio , Sanchez-Sanchez Purificacion , Villafranca-Sanchez Elena
Published: July 2016

This date list contains the results of 14C determinations of archaeologic samples from Spain and Portugal obtained at the Laboratory mostly from 1983 to July 1986. Preparation and measurements were made in the same manner as previously reported (R, 1982, v 24, no. 2, p 217–221; R, 1985, v 27, no. 3, p 610–615; R, v 28, no. 3, p 1200–1205).
The Relations Between Carbon Isotope Composition and Apparent Age of Freshwater Tufaceous Sediments
Authors: Pazdur Anna
Published: July 2016

This paper presents a synthetic approach to 14C dating of calcareous tufa, based on statistical analysis of correlations betwen lithologic type of tufaceous sediment, carbon isotope composition, and apparent age. Experimental data on several profiles from southern Poland and the United Kingdom reveal either constant or systematically changing values of apparent age. Constant value of apparent age in a profile can be attributed to calcareous muds precipitated from stagnant or low-energy water, and to tufas precipitated from turbulent water (oncoids, stromatolites, moss travertines) which are characterized by lack of significant correlation between δ13C and 14C age of tufa carbonate. It was found that the relation between the apparent age of tufaceous sediment and δ13C value of tufa carbonate depends on lithologic type of tufa. Phenomenological equations describing the dependence of apparent age upon δ13C are given, and applied to estimate true ages of tufas from Gliczarów (southern Poland) and Folkestone (United Kingdom).
Cultural Evolution and Paleogeography on the Santa Barbara Coast: A 9600-Year 14C Record from Southern California
Authors: Erlandson Jon M
Published: July 2016

Since 1984, a large multi-disciplinary archaeological team, under the direction of the author, has collected artifactual, ecofactual, and radiocarbon samples from a series of Native American sites spanning the past 9600 14C years. Occupied historically by the Chumash Indians, the Santa Barbara coast (Fig 1) has seen dramatic cultural and environmental change during the course of the Holocene. One of the goals of the research is to reconstruct patterns in the evolution of the local coastline, while examining the effects of environmental change on human adaptation along the Santa Barbara coast.
Improved Collagen Extraction by Modified Longin Method
Authors: Brown T A , Nelson D E , Vogel J S , Southon J R
Published: July 2016

A re-evaluation of the Longin collagen-extraction method shows that a lower reflux temperature reduces degradation of protein (“collagen”) remnants. This allows additional purification through ultrafiltration to isolate the >30kDalton fraction of the reflux product.
Microwave Oven Pretreatment of Carbonates for 14C Dating by Accelerator Mass Spectrometry
Authors: Lowe David C , Brailsford Gordon W , Drummond Gregory W
Published: July 2016

A microwave oven is used to pretreat carbonate samples prior to graphitization and radiocarbon dating by accelerator mass spectrometry. The method reduces the risk of contamination of small carbonate samples and provides a fast and convenient method for the acid evolution of CO2.
Edward Smith Deevey, Jr
Authors: Brenner Mark , Rice Prudence M.
Published: July 2016

Edward Smith Deevey, Jr died on November 29, 1988, following a heart attack. He was Graduate Research Curator of Paleoecology at the Florida Museum of Natural History, University of Florida, Gainesville. As a reflection of his expertise in many academic disciplines, Ed held Graduate Research Professorships in four University of Florida departments: zoology, botany, geology and Latin American studies.
US Geological Survey, Menlo Park, California Radiocarbon Measurements IV
Authors: Trimble Deborah A , Robinson Stephen W
Published: July 2016

The Menlo Park Radiocarbon Laboratory utilizes gas proportional counting of carbon dioxide in counters installed 9.5m below the ground surface for background reduction (Robinson, 1977, 1979; Robinson & Trimble, 1981, 1983). The reported results of geologic samples closely follow the guidelines of Stuiver and Polach (1977). The standard errors for analyses earlier than USGS-500 are based solely upon counting statistics, while later analyses include estimates of uncertainty in voltage, pressure, temperature, and δ13C. Unless otherwise noted, organic samples are pretreated in NaOH and HCl, and carbonate samples in HCl.
Correcting14C Histograms for the Non-Linearity of the Radiocarbon Time Scale
Authors: Stolk Ad , Hogervorst Koos , Berendsen Henk
Published: July 2016

Large numbers of14C dates of the base and top of Holocene peat layers may be plotted in14C histograms in order to establish statistically a chronology of periods of essentially clastic sedimentation and peat formation. Due to the non-linearity of the14C time scale in terms of calendar years, clustering of14C dates on random peat growth may occur. This seriously hampers the interpretation of histograms. A quantitative method and computer program were developed to correct the histograms for this effect. The correction factor that has to be applied depends on the calibration curve and the interval width of the correction parameter dy. For peat samples, an interval width of 10014C yr and a calibration curve based on a 100-yr moving average seems to be a reasonable choice.
Radiocarbon Dates for Lava Flows from Northeast Rift Zone of Mauna Loa Volcano, Hilo 7 1/2’ Quadrangle, Island of Hawaii
Authors: Buchanan-Banks J M , Lockwood J P , Rubin Meyer
Published: July 2016

Twenty-eight 14C analyses are reported for carbonized roots and other plant material collected from beneath 15 prehistoric lava flows erupted from the northeast rift zone (NERZ) of Mauna Loa Volcano (ML) utilizing the recovery techniques of Lockwood and Lipman (1980). Most samples were collected from the Hilo 7 1/2’ quadrangle during field work for a geologic map of that quadrangle (Buchanan-Banks, unpub data); a few sample sites are located in adjacent quadrangles: Piihonua to the west and Mountain View to the south. Altitudes are given in English units as well as metric to facilitate locating sites on USGS topographic maps.
Corrected Calibration of the Radiocarbon Time Scale, 3904–3203 Cal BC
Authors: de Jong Arie F M , Mook Willem G , Becker Bernd
Published: July 2016

Since our publication of the high-precision calibration curve for the larger part of the 4th millennium BC (de Jong, Becker & Mook, 1986), we found that the dendrochronologic scale (cal bc) needs a correction of 26 years. Instead of using the zero-point of the Niederwill chronology (4039 bc) which was floating at the time, our dendrochronologic scale was erroneously based on the zero-point of the Hohenheim master chronology, which, in its 1986 stage, extended to 4065 bc.
Dating Human Occupation on Diatom-Phytolith-Rich Sediment: Case Studies of Mustang Spring and Lubbock Lake, Texas, USA
Authors: Hatté Christine , Hodgins Gregory , Holliday Vance T , Jull A J Timothy
Published: July 2016

The Great Plains of North America have a rich archaeological record that spans the period from Late Glacial to Historic times, a period that also witnessed significant changes in climate and ecology. Chronometric dating of archaeological sites in many areas of the Great Plains, however, is often problematic, largely because charcoal and wood—the preferred materials for radiocarbon dating—are scarce in this grassland environment with few trees. Two reference archaeological sites are studied here: Mustang Spring and Lubbock Lake, Texas, USA. We carry out a geochronological approach based on a cross-study of carbon-derived data: combustion yield, δ13C,14C age differences between high temperature and low temperature released carbon, and the14C age itself. A study that incorporates multiple approaches is required to solve issues induced by the sedimentological context, which is rich in both freshwater diatoms and phytoliths from quite different origins. Analysis of carbon-derived data allows us to draw a succession model of dry and wet episodes and to associate it with a chronological framework. In this way, we can assert that, for the Mustang Spring site, several human occupations existed from ∼11 kyr BP to ∼8.7 kyr BP along the 110-cm-long series with an interruption of ∼150 yr that is associated with a palustrine environment between the Plainview and Firstview occupations.
Ams Dating of Human Bone from Cova De La Pastora: New Evidence of Ritual Continuity in the Prehistory of Eastern Spain
Authors: McClure Sarah B , Puchol Oreto García , Culleton Brendan J
Published: July 2016

We present the results of 10 AMS radiocarbon dates for Cova de la Pastora (Alcoi, Alicante), a burial cave attributed to the Late Neolithic/Chalcolithic in eastern Spain. The direct dating of 10 human mandibles from Cova de la Pastora indicates that the cave was used as a burial place from the Late Neolithic/Chalcolithic to the Bronze Age. These dates reveal a continuity of ritual use not previously identified at the site. This case also serves to highlight the utility of revisiting historic excavations and museum collections with modern techniques to shed new light on the prehistoric human record.
Reconstruction of 130-kyr Relative Geomagnetic Intensities from 10Be in Two Chinese Loess Sections
Authors: Zhou Weijian , Xian Feng , Beck J Warren , Jull A J Timothy , An Zhisheng , Wu Zhenkun , Liu Min , Chen Maobai , Priller Alfred , Kutschera Walter , Burr George S , Yu Huagui , Song Shaohua , Cheng Peng , Kong Xianghui
Published: July 2016

Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10Be records in 2 Chinese loess-paleosol sections using a correction based on the correlation of 10Be with magnetic susceptibility (SUS) to remove the climatic contamination. Both these records reveal the Laschamp and Blake events, which lie in the loess and paleosol (L1SS1 and S1SS3) horizons corresponding to mid-MIS 3 and 5e, respectively. The good agreement between our results and other geomagnetic intensities reconstructions from Atlantic and Pacific sediments indicates that our method is robust. Our study suggests the potential application of loess-paleosol 10Be for reconstructing geomagnetic intensity variations spanning the whole Quaternary.
Radiocarbon and Stable Carbon Isotope Analyses of Land Snails from the Chinese Loess Plateau: Environmental and Chronological Implications
Authors: Xu Bing , Gu Zhaoyan , Han Jingtai , Liu Zongxiu , Pei Yunpeng , Lu Yanwu , Wu Naiqin , Chen Yongfu
Published: July 2016

Paired radiocarbon and stable carbon analyses have been carried out on aragonite shells and organic soft bodies of snails from the Chinese Loess Plateau in order to explore the possibility of using these kinds of samples as environmental and chronological indicators. Results show that the soft bodies exhibit 14C concentrations similar to those of plant leaves, indicating that carbon in the soft bodies is fixed from organic diets. The aragonite shells are depleted in 14C compared to the soft bodies due to ingestion of 14C-depleted carbonate. This depletion shows a consistent pattern across the Chinese Loess Plateau, implying a good potential for the snail shells to be applicable for 14C dating with a simple correction. The δ13C values measured for aragonite shells display a linear relationship with those obtained for the soft bodies with a constant offset. In addition, the carbon derived from organic diets accounts for more than 70% of the total shell carbon. This fact suggests that stable carbon isotope composition of aragonite shells mainly reflects that of organic diet, and could be used as a reliable indicator of paleodiet in the Chinese Loess Plateau.
14C AMS at Suerc: Improving QA Data with the 5MV Tandem and 250KV SSAMS
Authors: Naysmith P , Cook G T , Freeman S P H T , Scott E M , Anderson R , Xu S , Dunbar E , Muir G K P , Dougans A , Wilcken K , Schnabel C , Russell N , Ascough P L , Maden C
Published: July 2016

In 2003, a National Electrostatics Corporation (NEC) 5MV tandem accelerator mass spectrometer was installed at SUERC, providing the radiocarbon laboratory with 14C measurements to 4–5‰ repeatability. In 2007, a 250kV single-stage accelerator mass spectrometer (SSAMS) was added to provide additional 14C capability and is now the preferred system for 14C analysis. Changes to the technology and to our operations are evident in our copious quality assurance data: typically, we now use the 134-position MC-SNICS source, which is filled to capacity. Measurement of standards shows that spectrometer running without the complication of on-line δ13C evaluation is a good operational compromise. Currently, 3‰ 14C/13C measurements are routinely achieved for samples up to nearly 3 half-lives old by consistent sample preparation and an automated data acquisition algorithm with sample random access for measurement repeats. Background and known-age standard data are presented for the period 2003–2008 for the 5MV system and 2007–2008 for the SSAMS, to demonstrate the improvements in data quality.
Radiocarbon Dates Documenting the Neolithic-Bronze Age Transition in Korea
Authors: Kim Jong Chan , Bae Christopher J
Published: July 2016

We report radiocarbon dates for ∼150 archaeological sites in Korea belonging to the Neolithic-Bronze Age transition period. From the present compilation, we find that the Neolithic-Bronze Age transition in Korea started as early as ∼2300 BC and continued over the course of 800–900 yr with peaks representing population increases occurring 2–3 times. Compared with cases in other regions of the world, the Neolithic-Bronze Age transition in Korea was similar in both magnitude and transition time. However, the process in Korea appears to have occurred about 2000 yr later. Further, we find that the attempt to explain the Neolithic-Bronze Age transition in Korea as a migration hypothesis based only on a sudden population increase is not tenable.
Radiocarbon Chronology for Early Caves of the Mogao Grottoes at Dunhuang, China
Authors: Qinglin Guo , Takabayashi Hiromi , Nakamura Toshio , Gangquan Chen , Okada Ken , Bomin Su , Yuquan Fan , Nishimoto Hiroshi
Published: July 2016

The Mogao Grottoes site at Dunhuang is one of the largest stone cave temples in China. The site features 735 caves with Buddhist mural paintings. To investigate the chronology of early caves of the Mogao Grottoes, radiocarbon dates were measured by accelerator mass spectrometry (AMS) on plant remains collected from 4 caves: 268, 272, 275, and 285. Caves 268, 272, and 275 are regarded (by archaeological analysis) to be the earliest existing caves in the Mogao Grottoes. The fourth cave, 285, features inscriptions on the north wall mentioning the oldest dates of the Chinese Mogao era. Plant materials, taken from the plaster layer of mural paintings and core materials from statues, were collected as samples (n = 11) for AMS 14C dating at Nagoya University. Two samples from cave 275 gave calibrated 14C ages of cal AD 380–430 (1 σ). The other samples resulted in a time interval of cal AD 400–550. The calibrated 14C ages obtained for the samples taken from painted murals and the statues in cave 285 are consistent with the date given by the inscription remaining on the cave's north wall.
Chronology of the Obi-Rakhmat Grotto (Uzbekistan): First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia
Authors: Krivoshapkin Andrei I , Kuzmin Yaroslav V , Jull A J Timothy
Published: July 2016

The Obi-Rakhmat Grotto is one of the key Paleolithic sites in Central Asia. Archaeological excavations have revealed 22 strata containing archaeological materials. Lithic assemblages from all cultural layers display features similar to both late Middle Paleolithic blade industries and early Upper Paleolithic complexes in Southwest Asia and the Siberian Altai Mountains; this suggests a gradual Middle-to-Upper Paleolithic transition occurred in western Central Asia. Hominid remains found at Obi-Rakhmat (layer 16) show a mixture of archaic and modern traits. Different chronometric methods (radiocarbon, optically stimulated luminescence [OSL], U-series, and electron spin resonance [ESR]) were applied to the site's deposits. It appears that 14C dates are more reliable in terms of correspondence to the general framework of the Paleolithic of Central Asia and neighboring regions, and after critical analysis and the deletion of outliers, the upper part of the site's cultural sequence can be dated between 36,000–41,400 BP (layer 7) and ∼48,800 BP (layer 14.1). The U-series dating results are less secure due to the high uranium content and the presence of detritus, which contaminates dated sediments (travertine). The OSL dating gave uniform ages for all cultural succession (∼8 m of deposits), and confirms a very rapid sedimentation rate. Results of ESR dating depend greatly on the choice of uptake model. Dates calculated for the early uptake to some extent correspond to 14C data. The linear uptake chosen by Skinner et al. (2007) makes sediments very old (about 55,000–90,000 yr ago), which contradicts 14C dates and does not correspond well to the regional archaeological context.
A Nondestructive Prescreening Method for Bone Collagen Content Using Micro-Computed Tomography
Authors: Tripp Jennifer A , Squire Maria E , Hamilton Julie , Hedges Robert E M
Published: July 2016

Isolation of bone collagen for radiocarbon dating is a labor-intensive and time-consuming process that sometimes results in unacceptably low protein recovery. In preliminary studies reported here, micro-computed tomography (microCT), a nondestructive technique that uses X-rays to produce high-resolution three-dimensional images of mineralized materials such as bone, offers promise as a suitable prescreening option for bones of questionable preservation. We have found that the bone volume fraction calculated by the scanner software correlates well with collagen recovery in 4 analyzed bones from Etton, United Kingdom.
Fire History of a Giant African Baobab Evinced by Radiocarbon Dating
Authors: Patrut Adrian , Mayne Diana H , von Reden Karl F , Lowy Daniel A , Pelt Robert van , McNichol Ann P , Roberts Mark L , Margineanu Dragos
Published: July 2016

The article reports the first radiocarbon dating of a live African baobab (Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15–20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are not correlated with their positions in the stems of the tree. Dating results indicate that the segments originate from new growth layers, with a thickness of several centimeters, which cover the original old wood. Four new growth layers were dated before the reference year AD 1950 and 2 layers were dated post-AD 1950, in the post-bomb period. Formation of these layers was triggered by major damage inside the cavities. Fire episodes are the only possible explanation for such successive major wounds over large areas or over the entire area of the inner cavities of the Platland tree, able to trigger regrowth.
Atmospheric Fossil Fuel CO2 Measurement Using a Field Unit in a Central European City During the Winter of 2008/09
Authors: Molnár M , Haszpra L , Svingor É , Major I , Svetlik I
Published: July 2016

A high-precision atmospheric CO2 monitoring station was developed as a field unit. Within this, an integrating CO2 sampling system was applied to collect samples for radiocarbon measurements. One sampler was installed in the second largest city of Hungary (Debrecen station) and 2 independent 14CO2 sampling lines were installed ∼300 km from Debrecen in a rural site at Hegyhátsál station as independent background references, where high-precision atmospheric CO2 mixing ratios have been measured since 1994. Fossil fuel CO2 content in the air of the large Hungarian city of Debrecen was determined during the winter of 2008 using both the measurements of CO2 mixing ratio and 14C content of air. Fossil fuel CO2 was significantly enhanced at Debrecen relative to the clean-air site at Hegyhátsál.
Developments in the Calibration and Modeling of Radiocarbon Dates
Authors: Ramsey Christopher Bronk , Dee Michael , Lee Sharen , Nakagawa Takeshi , Staff Richard A
Published: July 2016

Calibration is a core element of radiocarbon dating and is undergoing rapid development on a number of different fronts. This is most obvious in the area of 14C archives suitable for calibration purposes, which are now demonstrating much greater coherence over the earlier age range of the technique. Of particular significance to this end is the development of purely terrestrial archives such as those from the Lake Suigetsu sedimentary profile and Kauri tree rings from New Zealand, in addition to the groundwater records from speleothems. Equally important, however, is the development of statistical tools that can be used with, and help develop, such calibration data. In the context of sedimentary deposition, age-depth modeling provides a very useful way to analyze series of measurements from cores, with or without the presence of additional varve information. New methods are under development, making use of model averaging, that generate more robust age models. In addition, all calibration requires a coherent approach to outliers, for both single samples and where entire data sets might be offset relative to the calibration curve. This paper looks at current developments in these areas.
A Wiggle-Matched Date for the Copper Age Cemetery at Manerba Del Garda, Northern Italy
Authors: Barfield Lawrence H , Manning Sturt W , Valzolgher Erio , Higham Thomas F G
Published: July 2016

The cemetery in the Riparo Valtenesi rockshelter at Manerba del Garda in northern Italy is well known for its wooden burial chambers. These chambers are some of the best sources of evidence for 3rd millennium BC collective burial in Europe. To further refine the absolute dating of burial activity at the site (beyond the approximate data provided by a previous series of routine radiocarbon measurements), a charred construction oak timber was sampled from Chamber 133 for 14C dendro wiggle-matching (DWM). We present the results from the DWM analysis, the first of its kind for the Italian Copper Age as a whole, establishing a terminus post quem for construction of Chamber 133 ∼2955–2872 cal BC.
Frequency Distribution of14C Ages for Chronostratigraphic Reconstructions: Alaska Region Study Case
Authors: Michczyńska Danuta J , Hajdas Irka
Published: July 2016

In this study, we test the possibility of using databases of radiocarbon ages to estimate boundaries of climatic chronozones. The Alaska region was chosen and compared with chronozones of 2 European countries: Poland and the Netherlands. The study included setting up a database of14C ages published for climatic records from Alaska. Some 97414C determinations on organic samples were selected and used to establish chronozones for the Late Glacial and the Holocene for the Alaska region. The selected data were calibrated and a summed probability density function (PDF) was calculated. The shape analysis of the constructed frequency distribution of14C dates on calendar timescales together with the assumption about preferential sampling seems to be a useful tool for establishing calendar ages for boundaries of climatic periods, i.e. chronozones.
Assessing the Potential for Radiocarbon Dating the Scales of Australian Lungfish (Neoceratodus Forsteri)
Authors: James Kelly M , Fallon Stewart J , McDougall Andrew , Espinoza Tom , Broadfoot Craig
Published: July 2016

We present a novel application for radiocarbon dating by aging 4 scales from a single large adult lungfish (Neoceratodus forsteri) from the Burnett River, in Queensland, Australia. The relict fish species lack a solid crystalline otolith, which precludes the use of the otolith annuli as a reliable age indicator. Previous attempts to age lungfish using a number of techniques have had only limited success. We report on ages obtained from the dense lamellar bone of the scale, which were isolated from the organic layers that thicken and subsequently obscure the 14C signal. Using the characteristics of the bomb curve, 2 parameter von Bertanalffy growth functions were fit, providing an estimate of absolute age to be ∼65–70 yr. The information gleaned from this study will aid in assessing the population structure, and therefore management, of this vulnerable species.
Temporal and Spatial Variations in Freshwater14C Reservoir Effects: Lake Mývatn, Northern Iceland
Authors: Ascough P L , Cook G T , Church M J , Dunbar E , Einarsson Á , McGovern T H , Dugmore A J , Perdikaris S , Hastie H , Friðriksson A , Gestsdóttir H
Published: July 2016

Lake Mývatn is an interior highland lake in northern Iceland that forms a unique ecosystem of international scientific importance and is surrounded by a landscape rich in archaeological and paleoenvironmental sites. A significant freshwater reservoir effect (FRE) has been identified in carbon from the lake at some Viking (about AD 870–1000) archaeological sites in the wider region (Mývatnssveit). Previous accelerator mass spectrometry (AMS) measurements indicated this FRE was about 1500–190014C yr. Here, we present the results of a study using stable isotope and14C measurements to quantify the Mývatn FRE for both the Viking and modern periods. This work has identified a temporally variable FRE that is greatly in excess of previous assessments. New, paired samples of contemporaneous bone from terrestrial herbivores and omnivores (including humans) from Viking sites demonstrate at least some omnivore diets incorporated sufficient freshwater resources to result in a herbivore-omnivore age offset of up to 40014C yr. Modern samples of benthic detritus, aquatic plants, zooplankton, invertebrates, and freshwater fish indicate an FRE in excess of 500014C yr in some species. Likely geothermal mechanisms for this large FRE are discussed, along with implications for both chronological reconstruction and integrated investigation of stable and radioactive isotopes.
Development of an Automatic Sampling Unit for Measuring Radiocarbon Content of Groundwater
Authors: Janovics R , Molnár M , Futó I , Rinyu L , Svingor É , Veres M , Somogyi I , Barnabás I
Published: July 2016

An automatic water sampling unit was developed to monitor the radioactive emission (radiocarbon and other corrosion and fission products) from nuclear facilities into the groundwater. Automatic sampling is based on the principal of ion exchange using built-in resin columns in the submerging samplers. In this way, even the short-term emissions can be detected. According to our experiments, the 14C activity concentrations and the δ13C values of the samples made by the ion exchange method are systematically underestimated compared to the real values. The carbonate adsorption feature of the sampling unit was studied under laboratory and field conditions. For this purpose, a test method was developed. The observed sampling efficiencies and additionally some carbon contamination for the sampling method itself have to be taken into consideration when we estimate the amount of 14C contamination introduced into the groundwater from a nuclear facility. Therefore, a correction factor should be made for the 14C anion exchange sampling. With the help of this correction, the results converge to the expected value.
Compound-Specific Radiocarbon Analyses of Phospholipid Fatty Acids and N-Alkanes in Ocean Sediments
Authors: Druffel Ellen R M , Zhang Dachun , Xu Xiaomei , Ziolkowski Lori A , Southon John R , dos Santos Guaciara M , Trumbore Susan E
Published: July 2016

We report compound-specific radiocarbon analyses of organic matter in ocean sediments from the northeast Pacific Ocean. Chemical extractions and a preparative capillary gas chromatograph (PCGC) were used to isolate phospholipid fatty acids (PLFA) and n-alkanes from 3 cores collected off the coast of California, USA. Mass of samples for accelerator mass spectrometry (AMS) 14C analysis ranged from 13–100 μg C. PLFA extracted from anaerobic sediments in the Santa Barbara Basin (595 m depth) had modern Δ14C values (–20 to +54‰), indicating bacterial utilization of surface-produced, post-bomb organic matter. Lower Δ14C values were obtained for n-alkanes and PLFA from coast (92 m depth) and continental slope (1866 m) sediments, which reflect sources of old organic matter and bioturbation. We present a brief analysis of the blank carbon introduced to samples during chemical processing and PCGC isolation.
Extraction of In Situ Cosmogenic 14C from Olivine
Authors: Pigati Jeffrey S , Lifton Nathaniel A , Jull A J Timothy , Quade Jay
Published: July 2016

Chemical pretreatment and extraction techniques have been developed previously to extract in situ cosmogenic radiocarbon (in situ14C) from quartz and carbonate. These minerals can be found in most environments on Earth, but are usually absent from mafic terrains. To fill this gap, we conducted numerous experiments aimed at extracting in situ14C from olivine ((Fe,Mg)2SiO4). We were able to extract a stable and reproducible in situ14C component from olivine using stepped heating and a lithium metaborate (LiBO2) flux, following treatment with dilute HNO3 over a variety of experimental conditions. However, measured concentrations for samples from the Tabernacle Hill basalt flow (17.3 ± 0.3 ka4) in central Utah and the McCarty's basalt flow (3.0 ± 0.2 ka) in western New Mexico were significantly lower than expected based on exposure of olivine in our samples to cosmic rays at each site. The source of the discrepancy is not clear. We speculate that in situ14C atoms may not have been released from Mg-rich crystal lattices (the olivine composition at both sites was ∼Fo65Fa35). Alternatively, a portion of the 14C atoms released from the olivine grains may have become trapped in synthetic spinel-like minerals that were created in the olivine-flux mixture during the extraction process, or were simply retained in the mixture itself. Regardless, the magnitude of the discrepancy appears to be inversely proportional to the Fe/(Fe+Mg) ratio of the olivine separates. If we apply a simple correction factor based on the chemical composition of the separates, then corrected in situ14C concentrations are similar to theoretical values at both sites. At this time, we do not know if this agreement is fortuitous or real. Future research should include measurement of in situ14C concentrations in olivine from known-age basalt flows with different chemical compositions (i.e. more Fe-rich) to determine if this correction is robust for all olivine-bearing rocks.
Optimization of the Graphitization Process at Age-1
Authors: Němec Mojmír , Wacker Lukas , Gäggeler Heinz
Published: July 2016

The reaction conditions for the graphitization of CO2 with hydrogen were optimized for a fast production of high-quality carbon samples for accelerator mass spectrometry (AMS) measurement. The iron catalyst in use is first oxidized by heating with air to remove possible carbon and other impurities and then after evacuation reduced back to iron with hydrogen in several flushing steps to remove any iron oxide. The optimum conditions for a fast graphitization reaction were experimentally determined by changing the reaction temperatures and the H2/CO2 ratio. The resulting graphite samples were measured by AMS to find the smallest isotopic changes (δ13C) at a minimum of molecular fragment formation (13CH current). The improvements are based on thermodynamic data and are explained with Baur-Glaessner diagrams.
Studies on the Preparation of Small 14C Samples with an RGA and 13C-Enriched Material
Authors: Liebl Jakob , Ortiz Roswitha Avalos , Golser Robin , Handle Florian , Kutschera Walter , Steier Peter , Wild Eva Maria
Published: July 2016

The minimum size of radiocarbon samples for which reliable results can be obtained in an accelerator mass spectrometry (AMS) measurement is in many cases limited by carbon contamination introduced during sample preparation (i.e. all physical and chemical steps to which samples were subjected, starting from sampling). Efforts to reduce the sample size limit down to a few μg carbon require comprehensive systematic investigations to assess the amount of contamination and the process yields. We are introducing additional methods to speed up this process and to obtain more reliable results. A residual gas analyzer (RGA) is used to study combustion and graphitization reactions. We could optimize the reaction process at small CO2 pressures and identify detrimental side reactions. Knowing the composition of the residual gas in a graphitization process allows a reliable judgment on the completeness of the reaction. Further, we use isotopically enriched 13C (≥98% 13C) as a test material to determine contamination levels. This offers significant advantages: 1) The measurement of 12C/13C in CO2 is possible on-line with the RGA, which significantly reduces turnaround times compared to AMS measurements; 2) Both the reaction yield and the amount of contamination can be determined from a single test sample.

The first applications of isotopically enriched 13C and the RGA have revealed that our prototype setup has room for improvements via better hardware; however, significant improvements of our sample processing procedures were achieved, eventually arriving at an overall contamination level of 0.12 to 0.15 μg C during sample preparation (i.e. freeze-drying, combustion, and graphitization) of μg-sized samples in aqueous solution, with above 50% yield.
Measurement of 10Be Concentration of Modern Falling Dust in Northern China
Authors: Xian Feng , Zhou Weijian , Kong Xianghui , Jiang Jun , Wu Zhenkun , Chen Ning , Zhao Guoqing
Published: July 2016

Paleoenvironmental and paleogeomagnetic tracing studies from Chinese loess10Be have progressed in recent years (Zhou et al. 2007a,b, 2010). In this approach,10Be flux determined from sediment concentration and accumulation rate may be used to recover information about paleomonsoon rainfall rates as well as past variations in the geomagnetic field strength. However, these methods require that a correction be made for residual undecayed10Be in remobilized dust. To better understand the feature of the10Be signals related to the remobilized dust, we report the first observational study on10Be concentration of modern falling dust using the 3MV multi-element accelerator mass spectrometer (AMS) in the Xi'an AMS Center. Ten samples collected at Ansai observation station (109°19′E, 36°51′N) in northern China from May 2008 to June 2009 are measured along with 3 chemical blanks. The results clearly show that the10Be content of modern falling dust is relatively uniform, with a mean value of 1.21 x 108atoms/g, a measurement similar to that of Chinese loess (Zhou et al. 2007a) and to the value found in the study by Shen et al. (2009) on dust10Be falling near Dingbian, China (1.25 ± 0.06 x 108atoms/g). Despite the fact that modern dust flux is much higher in spring relative to summer in northern China,10Be concentration in falling dust remains fairly constant. In addition, we find that dust10Be concentration is roughly independent of the local precipitation changes. This feature might be considered as an analogue to improve our understanding on the fundamental information of the source component contained in loess10Be records and its spatial/temporal distribution features.
Radiocarbon and Stable Carbon Isotopes in Two Soil Profiles from Northeast India
Authors: Laskar Amzad H , Yadava M G , Ramesh R
Published: July 2016

Two soil profiles from northeast India, one from Bakrihawar, an agricultural land, and the other from Chandipur, a virgin hilly area from Assam, are investigated to understand the organic carbon dynamics of the area. Due to frequent flooding, the Bakrihawar soil has accumulated a higher clay content than that of Chandipur. The carbon content is less than 1% by weight in both the sites. The higher clay content is responsible for relatively more soil organic carbon at Bakrihawar. The mean δ13C values at both sites reflect the values of the overlying vegetation. At Bakrihawar, both rice cultivation (C3) and natural C4grasses contribute to higher mean enriched values of13C relative to Chandipur, where the surface vegetation is mostly of C3type. The turnover time of organic carbon, estimated using the residual radiocarbon content, depends strongly on the soil particle size distribution, especially the clay content (i.e. it increases with clay content). To the best of our knowledge, this is the first soil carbon dynamics study of its kind from northeast India.
Radiocarbon Dating of Pleistocene Fauna and Flora from Starunia, SW Ukraine
Authors: Kuc T , Różański K , Kotarba M J , Goslar T , Kubiak H
Published: July 2016

New attempts arc presented to determine the age of large Pleistocene mammals excavated at Starunia, ∼130 km southeast of Lviv, Ukraine. This remarkable discovery made at the beginning of the 20th century included a complete carcass of woolly rhinoceros (No. 2), fragments of 3 woolly rhinoceroses (Nos. 1, 3, and 4) and remnants of numerous specimens of other fossil fauna and flora. Although attempts to date paleontological findings from Starunia site go back to the early 1970s, the results obtained before 2006 arc somewhat misleading, mostly due to unresolved contamination problems. Comprehensive cleaning of the samples adopted in the framework of this study was aimed at removal of 2 potential sources of contamination: (i) radiocarbon-free hydrocarbons abundant at the burial site; and (ii) allochthonous organic materials containing contemporary carbon that were used in the past during preservation of the dated specimens. Two types of samples have been analyzed for their14C content in the framework of the present study: (i) fragments of bones and teeth collected from specimens stored or exposed in the Natural History museums in Lviv and Kraków; and (ii) samples of terrestrial macrofossils retrieved from sediment cores obtained during the 2007–2008 field campaigns in the Starunia area.14C analyses of collagen were supplemented by measurements of its elemental C/N ratio and13C/12C and15N/14N isotope ratios. Three14C dates obtained for rhinoceros No. 2 span the age range from 35.3 to 40.0 ka BP, in agreement with the minimum age estimated from macrofossils. The mean value of 37.7 ± 1.7 ka BP falls in the range of ages reported for big Pleistocene mammals from other locations in Europe. The bones of rhinoceros No. 3, which were found in close vicinity to those of rhinoceros No. 2, reveal a14C age of 36.7 ± 0.6 ka BP. The δ15N and δ13C values obtained for collagen extracted from bones and teeth belonging to rhinoceroses Nos. 1, 2, and 3 are in a broad agreement with analogous literature data for large Pleistocene mammals found in other sites in Europe, North America, and Siberia.
Rudjer Bošković Institute Radiocarbon Measurements XVII
Authors: Horvatinčić Nada , Bronić Ines Krajcar , Obelić Bogomil , Barešić Jadranka
Published: July 2016

This paper presents dating results of geological (speleothems, tufa, soil, and sediment), biological (mollusks and botanical), as well as hydrogeological samples from Croatia, Slovenia, Bosnia and Herzegovina, Turkey, and China. Included arc results of samples measured by gas proportional counting (GPC) in the Zagreb lab until abandonment of this technique in 2007, as well as results of several series measured by both GPC and liquid scintillation counting (LSC) methods.