bluuebunny/crossref_metadata_2025 huggingface dataset:
Late Holocene Environmental Reconstruction of St. Michiel Saline Lagoon, Curaçao (Dutch Antilles)
Authors: Klosowska Bogumila B , Troelstra Simon R , van Hinte Jan E , Beets Dirk , VAN der Borg Klaas , de Jong Arie F M
Published: July 2016

Two sediment cores collected from the saline lagoon St. Michiel on Curaçao (Dutch Antilles) preserve a ~5000-yr record of environmental change. Investigation of radiocarbon-dated sections by accelerator mass spectrometry (AMS) is based on faunal assemblage analyses, sediment mineralogy, and the interpretation of sedimentary facies. The cores recovered from different parts of the lagoon demonstrate different development. Initially, in the proximal part of the lagoon (core STM-2), the sediment accumulated in a coastal, semi-protected bay with strong marine influence, whereas the distal part (STM-1) was dominated by chemical precipitation (gypsum, aragonite). By about 3500–3400 BP, connection with the open sea became very limited due to the gradual formation of a coral rubble barrier at the coastline. Subsequently, the record reveals undisturbed sedimentation in the highly restricted shallow lagoon. Around 1100–1000 BP, biological and sedimentological records indicate a change to less evaporitic conditions. Stages of increased salinity are intercalated with intervals of episodic freshening due to increased runoff and precipitation. The authors demonstrate that since permanent human settlements were established on the island about 1100 BP, the watershed has undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century. Deforestation resulting from agriculture and construction caused increased erosion, which was translated to increased sediment accumulation rates and a shift in lagoon sedimentation from almost entirely endogenic to mostly detrital.
14C Sources and Distribution in the Vicinity of La Hague Nuclear Reprocessing Plant: Part Ii—Marine Environment
Authors: Maro D , Fontugne M , Hatté C , Hebert D , Rozet M
Published: July 2016

Carbon dioxide partial pressure and radiocarbon activity were measured in air and seawater in the Bay of Seine and around the COGEMA-La Hague nuclear reprocessing plant (northwest France) during 3 cruises in 2000 and 2002. Results clearly show that the sea is a source of CO2 and 14C to the atmosphere. High 14C concentrations in air and water related to the La Hague liquid waste are clearly recorded. For the restricted area of the Bay of Seine, CO2 carbon and 14C fluxes were estimated, indicating that less than 3% of the liquid 14C release is introduced in the atmosphere.
Spatial and Temporal Impacts of 14C Releases from the Sellafield Nuclear Complex On the Irish Coastline
Authors: Keogh Sinead M , McGee Edward J , Gallagher Donal
Published: July 2016

The Sellafield nuclear fuel reprocessing plant is estimated to be the largest single source of global anthropogenic radiocarbon discharge. This study addresses the impact of these releases on the Irish coastal marine environment. Spatial trends in the 14C content of seaweed (Fucus spp.) were assessed by collecting and analyzing samples from well-distributed locations around the Irish coastline. Temporal trends were studied by comparing 14C concentrations in present-day samples with levels found in archive material collected at the same locations during research campaigns conducted in the mid-1980s and mid-1990s. The impact of 14C discharged from Sellafield was found to be most apparent in seaweeds from the northeastern Irish coast. This indicates that the pattern of residual currents and, in particular, the south to north transfer of water known to predominate in the Irish Sea, largely controls the spatial distribution of 14C releases. Maximum 14C discharge levels to the marine environment from Sellafield (between 12 and 13 TBq yr-1) were mirrored by peak concentrations found in seaweed from the mid-1990s and in present-day samples (highest recorded value of 130.4 pMC). Concentrations of 14C in seaweed from the west coast of Ireland correspond closely with values measured for seaweeds from the Atlantic coast of northwest Spain and do not appear to be significantly affected by Sellafield discharges.
Wiggle-Match Dating of Tree-Ring Sequences
Authors: Galimberti Mariagrazia , Bronk Ramsey Christopher , Manning Sturt W
Published: July 2016

Given the non-monotonic form of the radiocarbon calibration curve, the precision of single 14C dates on the calendar timescale will always be limited. One way around this limitation is through comparison of time-series, which should exhibit the same irregular patterning as the calibration curve. This approach can be employed most directly in the case of wood samples with many years growth present (but not able to be dated by dendrochronology), where the tree-ring series of unknown date can be compared against the similarly constructed 14C calibration curve built from known-age wood. This process of curve-fitting has come to be called “wiggle-matching.”

In this paper, we look at the requirements for getting good precision by this method: sequence length, sampling frequency, and measurement precision. We also look at 3 case studies: one a piece of wood which has been independently dendrochronologically dated, and two others of unknown age relating to archaeological activity at Silchester, UK (Roman) and Miletos, Anatolia (relating to the volcanic eruption at Thera).
New ΔR Values for the Southwest Pacific Ocean
Authors: Petchey Fiona , Phelan Matthew , Peter White J
Published: July 2016

ΔR results of known-age shells from the Solomon and Coral Seas and the northwest coast of New Ireland are presented. The results are too few to be conclusive but indicate that ΔR in this region is variable. An average ΔR value of 370 ± 25 yr is recorded for a range of shell species from Kavieng Harbor, New Ireland, and is primarily attributed to weak equatorial upwelling of depleted 14C due to seasonal current reversals. In contrast, values from the Solomon and Coral Seas are lower (average ΔR = 45 ± 19 yr). Higher ΔR values for some shellfish from these 2 seas is attributed to ingestion of 14C-depleted sediment by deposit-feeding species.
University of Bonn Natural Radiocarbon Measurements III
Authors: Scharpenseel H. W. , Pietig F.
Published: July 2016

The laboratory has continued to concentrate on soil and water dating, using the benzene method as outlined in Scharpenseel and Pietig (1969a).
Isotopes’ Radiocarbon Measurements VIII
Authors: Buckley James D. , Willis Eric H.
Published: July 2016

This date list presents results of samples measured at ISOTOPES during 1968 and 1969 and several measurements made previously for which complete sample data has recently been received.
Vienna Radium Institute Radiocarbon Dates I
Authors: Felber Heinz
Published: July 2016

A dating system consisting of gas sample counter with internal anticoincidence counter ring, transistorized electronic equipment, and chemical apparatus was developed in the Institute (Felber and Vychytil, 1962; Felber, 1965). A high voltage supply Fluke Model 408B is used. For routine dating, begun in 1965, an improved 2.4 L counter with Teflon insulators is used, shielded on all sides by 20 cm of iron. The counter is run with methane at 760 torr/15°C. Spurious counts are carefully eliminated by a systematic procedure (Felber, 1966). Stability of electronics and counter is checked once a day by taking the topmost part of the peak of Mnα-X-rays following electron capture in Fe-55, radiated through a beryllium window. Checking is done with the same single channel analyzer (switched over to operation with small window) used for energy discrimination (switched over to two discriminator operation) during measurement. If any change should be observed, discriminator settings are corrected. Energy discrimination is not optimized (Felber, 1962) because a neutron generator using (d,t) reaction is run in the same building in which the samples are prepared: the lower discriminator is set above tritium maximum energy at 22 keV, the upper one at 120 keV, the highest possible energy absorption of C14β particles in the special counter. The background is 1.58 cpm, the net contemporary value (95% of NBS oxalic acid standard activity) is ca. 8.8 cpm.
Cambridge University Natural Radiocarbon Measurements V
Authors: Godwin H. , Willis E. H.
Published: July 2016

The dates and activity measurements given below have been obtained during the year 1961, and have been made with CO2at 3 atmospheres pressure in a proportional gas counter as described in previous contributions from this laboratory.
Hannover Radiocarbon Measurements I
Authors: Wendt Immo , Schneekloth Heinrich , Budde Enno
Published: July 2016

The following list covers the measurements in our institute until the end of 1960.
Hannover Radiocarbon Measurements II
Authors: Geyh M. A. , Schneekloth H. , Wendt I.
Published: July 2016

The results described herein are measurements performed in 1961. Sample preparation and conversion into acetylene have been described (Wendt, Schneekloth and Budde, 1962). In calculating errors we did not follow the procedure used in our Date List I, where only the standard deviations of counting rates were used. The errors attached to the dates listed below include systematic errors due to sample preparation and small changes in the counting characteristics of sample, background, and standard counting gas.
Tata Institute Radiocarbon Date List I
Authors: Kusumgar S. , Lal D. , Sarna R. P.
Published: July 2016

The first series of C14 dates obtained in the C14 Laboratory of the above Institute, since it became operational in August 1961, are presented. The chemical and counting procedures adopted for the measurement of C14 in our laboratory have been described in some detail (Kusumgar et al., 1962). For the sake of completeness some points relevant to the determination of dates are described below.
Yale Natural Radiocarbon Measurements VIII
Authors: Stuiver Minze , Deevey Edward S. , Rouse Irving
Published: July 2016

No important instrumental modifications have been made since publication of our last list (Yale VII). As before, we are indebted to many collaborators for samples and for assistance with descriptions and comments. Technical assistance has been provided by George Young, Carolyn Haupt, and Jonathan Wood. The generous support of the National Science Foundation, under grants G-19080 (to Stuiver), G-19335 (to Deevey), and G-24049 (to Rouse) is gratefully acknowledged.
Pretreatment of Wood and Char Samples
Authors: Schultz Hyman , Currie L. A. , Matson F. R. , Miller W. W.
Published: July 2016

It has been shown that contamination from humic acids, chitin, fungal products, etc., contributing young carbon, and from bitumen and carbonate, contributing old carbon, may not be completely removed from wood and char samples by the usual hydrochloric acid and sodium hydroxide pretreatments of the samples. A procedure is offered for the isolation of a pure chemical substance from such samples, cellulose from wood and uncombined carbon from char, that must represent the original material. Cellulose is prepared by boiling the resin-free sample in 1.25% H2SO4 and 1.25% NaOH, adding Schweitzer's reagent, filtering, and precipitating from the filtrate by acidification. Uncombined carbon is separated from char samples as the flocculant precipitate remaining after boiling in 70% HNO3, followed by settling overnight from a large volume of 6M HNO3. A simple procedure for the chemical examination of char samples is also offered for the estimation of the amounts of bitumen, carbonate, combined, and uncombined carbon in char.
Stockholm Natural Radiocarbon Measurements VI
Authors: Engstrand Lars G.
Published: July 2016

The C14 dates given below are a continuation of the work presented in our earlier lists (Stockholm I, II, III, IV, and V). The apparatus and technique are the same as described in Stockholm V.
University of Texas Radiocarbon Dates III
Authors: Pearson F. J. , Davis E. Mott , Tamers M. A. , Johnstone Robert W.
Published: July 2016

This list reports measurements made at this laboratory since the preparation of the last list (Texas II). About twenty measurements are not reported because they are from series which are incomplete. Ages were calculated using a C14 half-life of 5568 yr and 1950 as the reference year. The modern standard used was 95% of NBS oxalic acid activity. The deviations reported are based on the counting statistics of the sample, background, and modern, and are ±1σ except that when the sample count approached either the modern standard or the background, 2σ limits are reported.
US Geological Survey, Denver, Colorado Radiocarbon Dates III
Authors: Yang I C , McAvoy R L , Emerson R L
Published: July 2016

This list contains the results of measurements made during 1978 and 1979. Ages were computed on the radiocarbon half-life of 5568 ± 30 years. Statistical errors quoted herein are 1σ counting errors which include sample, background, and standard. The age limit reported is calculated on the basis of 3σ activity. The σ13C values in table 1 were measured by Krueger Enterprises, Inc, Geochron Laboratories Division1 and calculated based on Craig's Peedee Belemnite (PDB) limestone standard (Craig, 1957). The total alkalinity as bicarbonate values reported in table 1 was determined using techniques described by Brown, Skougstad, and Fishman (1970). Unless otherwise stated, all samples were collected and submitted by personnel of the US Geological Survey.
University of Saskatchewan Radiocarbon Dates IX
Authors: Rutherford A A , Wittenberg Juergen , Wilmeth Roscoe
Published: July 2016

This series reports some of the measurements made since publication of the previous list (R, 1979, v 21, p 48–94). Acetylene proportional gas counting methods essentially remain as described in Saskatchewan II (R, 1960, v 2, p 73). Bone dating is now carried out on soluble collagen extract (Longin, 1971). The laboratory is associated with the National Museum of Canada to provide radiocarbon dating service for Canadian archaeologists but commercial services are also available to others.
University of Pennsylvania Radiocarbon Dates Xxi
Authors: Meulengracht Anne , McGovern Patrick , Lawn Barbara
Published: July 2016

This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R, 1978, v 20, p 210–233), as well as some samples dated previously which lacked adequate sample information.
US Geological Survey, Menlo Park, California, Radiocarbon Measurements II
Authors: Robinson Stephen W , Trimble Deborah A
Published: July 2016

The Menlo Park radiocarbon laboratory of the US Geological Survey began operation in January 1976 in a new building with a counting room 9.8m below the ground surface. Shielding above the counters consists of 30cm lead and 8.2m earth. The ionizing cosmic ray flux at the counters is 0.28 cpm/cm2. Background levels obtained thus far are summarized in Table 1.
University of Lund Radiocarbon Dates XIV
Authors: Håkansson Sören
Published: July 2016

Most of the 14C measurements reported here were made between October 1979 and October 1980. 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).
Rudjer Bošković Institute Radiocarbon Measurements VI
Authors: Srdoč Dušan , Sliepčevic Adela , Obelic Bogomil , Horvatinčic Nada
Published: July 2016

The following radiocarbon date list contains dates of samples measured since our previous list (R, 1979, v 21, p 131-137). As before, age calculations are based on the Libby half-life 5570 ± 30 yr and reported in years before 1950. The modern standard is 0.95 of the activity of NBS oxalic acid. Sample pretreatment, combustion, and counting technique are essentially the same as described in R, 1971, v 13, p 135-140, supplemented by new techniques for groundwater processing (R, 1979, v 21, p 131-137) and for soil sample treatment (R, 1977, v 19, p 465-475).
Accelerator Mass Spectrometry at High Voltage Engineering Europa (HVEE)
Authors: Gottdang A , Klein M , Mous D J W
Published: July 2016

In recent years, High Voltage Engineering Europa (HVEE) has demonstrated its capability of developing and installing turnkey accelerator mass spectrometry (AMS) equipment for the analysis of, among others, 14C and 129I. Five 3MV systems using sequential and/or simultaneous injection are operational in the field today, and they have shown excellent long-term stability providing high-precision analyses on a routine basis. Another three AMS systems are in production. It is projected that for the time being, AMS will continue to broaden its field of applications; a saturation of the market of AMS facilities is not expected in the near future.

To meet the specific demands of the biomedical research community, we have developed an extreme compact 14C AMS system comprising a hybrid ion source capable of handling both graphite as well as CO2 samples. The source is optimized for easy maintenance, accommodates up to 200 samples, and can be implemented in any other AMS system.

More recently, HVEE has initiated the development of an AMS system capable of detecting, among others, 36Cl and 41Ca. The design will include a HVEE 5MV Tandetron™. The accelerator is currently under construction as part of an ion beam analysis system for the Universidad Autonoma de Madrid (Spain).
Cosmic Background Reduction in the Radiocarbon Measurements by Liquid Scintillation Spectrometry at the Underground Laboratory of Gran Sasso
Authors: Plastino Wolfango , Kaihola Lauri , Bartolomei Paolo , Bella Francesco
Published: July 2016

Radiocarbon measurements by two 1220 Quantulus™ ultra low background liquid scintillation spectrometers were performed at the underground laboratory of Gran Sasso and the Radiocarbon Laboratory of E.N.E.A.-Bologna to study the efficiency and background variations related to measurement sites. The same configuration setup, i.e. the same center of gravity of the 14C spectrum (SQP(I) = 410 ± 1) was obtained in both instruments. Many different background and modern standards with pure analytical benzene were used and spectra for 40 one-hour periods were obtained. The data indicates a background reduction of approximately 65% between the surface and underground laboratories, with no differences in the efficiency. Recording similar efficiencies in both spectrometers is probably due to fairly identical photomultiplier characteristics. The cosmic noise reduction observed at the laboratory of Gran Sasso makes it possible to perform high precision 14C measurements and to extend for these idealized samples the present maximum dating limit from 58,000 BP to 62,000 BP (5 mL, 3 days counting).
Progress at the Seoul National University AMS Facility
Authors: Kim J C , Park J H , Kim I C , Lee C , Cheoun M K , Kang J , Song Y M
Published: July 2016

The accelerator mass spectrometry facility at the Seoul National University (SNU-AMS) was completed in December 1998 and a report was presented at the Vienna AMS conference in September 1999. At the conference, we described the basic components of our accelerator system and reported the results of the performance test. Since then, extensive testing of the accuracy and reproducibility of the system has been carried out, and about 200 unknown samples have been measured so far. We obtained a precision of 4‰ for modern samples, and an accuracy of approximately 40 yr was demonstrated by analyzing samples that were previously dated with a conventional technique and by other AMS laboratories. We present these results here, together with detailed descriptions of our data-taking and analysis procedures.
Chemical Removal of Conservation Substances by “Soxhlet“-Type Extraction
Authors: Bruhn Frank , Duhr Alexander , Grootes Pieter M , Mintrop Annette , Nadeau Marie-Josée
Published: July 2016

At the Leibniz radiocarbon lab, art and archaeological objects, often chemically conserved and thus potentially contaminated with respect to their 14C content, are treated using a computer-controlled “Soxhlet”-type series extractor. This device uses a continuous procedure of boiling and condensation of different solvents for extraction and vacuum filtration under constant process conditions. An elutrope sequence of five solvents that dissolve most customary conservation chemicals was selected. A study of these different contaminants applied to reference wood samples with subsequent accelerator mass spectrometry (AMS) measurements demonstrates that their effective removal is dependent on the use of adequate solvents. For many contaminants (e.g. wood glue, methyl cellulose, Klucel®, sugar, and polyethylene glycol), routine acid-alkali-acid (AAA) treatment already yields satisfactory results, whereas for Caparol® and beeswax a relatively “mild” treatment with acetone, methanol, water, and subsequent standard AAA extraction is sufficient. Complete removal of rubber glue, epoxy resin, and paraffin can only be accomplished with our full set of solvents. The latter procedure is also appropriate when no or only incomplete information about the type of conservation material is available. For epoxy resin the contamination appears to be enriched in the alkali residue, and the easily soluble “humic acid” fraction, even after standard AAA treatment, gives satisfactory results. Two case studies on the application of the extraction procedures are presented.
‘Transition Dating’ – a Heuristic Mathematical Approach to the Collation of Radiocarbon Dates from Stratified Sequences
Authors: Sharon Ilan
Published: July 2016

A heuristic approach, nicknamed “transition dating,” was used to date sequences of early Iron Age contexts using a series of 14C determinations. The basic principles of transition dating are simple and intuitive: 1) attempt to date transitions between periods, phases, etc. rather than the phases themselves, and 2) the most plausible date for that transition is one that is later than the dates from contexts preceding it, and is still earlier than the dates succeeding it. Hypotheses regarding the actual date of each transition may be evaluated using an appropriate loss function. These loss functions can also be adjusted or weighted by the user to account differentially for the various factors causing the distortion or “fuzz” in the dates.
Radiocarbon Chronology of the Holocene Dead Sea: Attempting a Regional Correlation
Authors: Frumkin Amos , Kadan Galit , Enzel Yehouda , Eyal Yehuda
Published: July 2016

Holocene sedimentary and geomorphic sequences from the Dead Sea region, Israel, are compared by correlation of more than 50 radiocarbon dates. The 14C dates provided the chronological basis that enabled us to detect basin-scale events that are hard to ascertain in single-site records. This paper is the first attempt to compare different Holocene records from several sites along the Dead Sea, based on their chrono-stratigraphy. Included is the first publication of the paleoclimatic record of the Nahal Darga ephemeral stream valley. Such a regional compilation is needed, because only the integration and comparative evaluation of several records can produce a reliable climatic history by establishing the height of former Dead Sea levels that may be complicated by tectonics and the rise of Mount Sedom. A relatively high level of the Holocene Dead Sea occurred during the mid-Holocene around 4400 BP or about 3000 cal BCE after calibration. The lake level fell sharply around 4000 BP, i.e. 2500 cal BCE, and later fluctuated close to early 20th century levels. The 14C-based correlation is also used to estimate the rising rates of the Mount Sedom salt diapir that are apparently smaller than 10 mm per year.
Proto-Neolithic and Neolithic Cultures in the Middle East—the Birth of Agriculture, Livestock Raising, and Ceramics: a Calibrated 14C Chronology 12,500-5500 cal BC
Authors: Aurenche O , Galet P , Régagnon-Caroline E , Évin J
Published: July 2016

We present for the first time a fully calibrated radiocarbon chronology of Proto-Neolithic and Neolithic cultures in the Middle East covering the time range from 12,500 to 5500 cal BC. A total of 1300 14C dates were evaluated, leading to the selection of 731 reliable dates. These were calibrated in a special collective approach presented in a series of graphs. The 14C dates are derived from 160 sites across the Middle East. The period with Proto-Neolithic cultures began around 12500 cal BC and lasted for more than 4000 years. The true Neolithic, with agriculture and livestock breeding, appeared just before 8000 cal BC, subsequently spreading across a wide area within just a few hundred years. Ceramics first occurred around 7000 cal BC. The Mesopotamian cultures that emerged around 6000 cal BC started the urban revolution.
The Chronology of the Ghassulian Chalcolithic Period in the Southern Levant: New14C Determinations from Teleilat Ghassul, Jordan
Authors: Bourke Stephen , Lawson Ewan , Lovell Jaimie , Hua Quan , Zoppi Ugo , Barbetti Michael
Published: July 2016

This article reports on ten new accelerator mass spectrometry (AMS) dates from the Chalcolithic period (fifth millennium BC) archaeological type-site of Teleilat Ghassul in Jordan. Early radiocarbon assays from the site proved difficult to integrate with current relative chronological formulations. The ten new AMS dates and follow-up enquiries connected with the early assays suggest that the original dates were up to 500 years too early. A necessary reformulation of regional relative chronologies now views the Ghassul sequence falling between Late Neolithic Jericho and the Beersheban Chalcolithic.
The Chalcolithic Radiocarbon Record and Its Use in Southern Levantine Archaeology
Authors: Burton Margie , Levy Thomas E
Published: July 2016

Archaeological evidence suggests that the Chalcolithic period (5th–4th millennium BCE) in the southern Levant was a time of significant settlement expansion and increasing social complexity. Important technological and social developments during this era set the stage for the later rise of fortified sites and nascence of urbanization in the Early Bronze Age. Controversy surrounding the chronology of Chalcolithic settlement and the reconstruction of social trajectories has stimulated an interest in building a database of radiocarbon dates to measure the tempo of change and help resolve these issues. To facilitate social evolutionary research, this paper reviews and updates published 14C data for the southern Levantine Chalcolithic. The now-substantial database supports the generally accepted time frame for this archaeological period and allows synchronic comparisons across diverse geographic subregions in the southern Levant. In addition, it helps to temporally place the emergence of sophisticated technologies and the development of complex social institutions within the Chalcolithic period. However, radiometrically based attempts at pan-regional internal periodization of the Chalcolithic and fine-tuning of protohistoric events such as site establishment and abandonment are frustrated by the lack of precision in 14C dates, which limits their ability to resolve chronological sequence. Improved delineation of Chalcolithic social trajectories can be achieved most effectively by focussing research efforts on stratigraphic and typological investigations of deeply-stratified settlement sites such as Teleilat Ghassul and Shiqmim within their local contexts.
New Radiocarbon Dates for the Reed Mat from the Cave of the Treasure, Israel
Authors: Aardsma Gerald E
Published: July 2016

Modern radiocarbon dates were procured for the Cave of the Treasure, Israel reed mat at the University of Arizona accelerator mass spectrometry (AMS) laboratory in late 1999 and early 2000. Three samples from various locations on the mat were dated. One of these samples was dated twice, and another was dated three times, yielding a total of six new radiocarbon dates on the mat. The new 14C dates overturn expectations of a late Chalcolithic, roughly 3500 BC, date for the origin of the mat. It is suggested that the mat may not have been of common use but may rather have been a religious heirloom with a history stretching back into the early Chalcolithic.
Precision of Calibrated Radiocarbon Ages of Historic Earthquakes in the Dead Sea Basin
Authors: Ken-Tor Revital , Stein Mordechai , Enzel Yehouda , Agnon Amotz , Marco Shmuel , Negendank Jorg F W
Published: July 2016

The precise determination of the age of historical and geological events by radiocarbon dating is often hampered by the long intersection ranges of the measured data with the calibration curve. In this study we examine the possibility of narrowing the calibrated range of the 14C ages of earthquake-disturbed sediments (seismites) from the Late Holocene lacustrine section in the Dead Sea Basin. The calibrated ranges of samples collected from seismites were refined by applying stratigraphic constraints and tuning the calibrated ranges to known historical earthquakes. Most of the earthquakes fall well within the 1σ error envelope of the 14C age. This refinement demonstrates that the lag period due to transport and deposition of vegetation debris is very short in this arid environment, probably not more than a few decades. This assessment of seismite 14C ages attests to the validity of 14C ages in Holocene sediments of the arid area of the Dead Sea. Furthermore, it demonstrates our ability to achieve highly precise (correct to within several decades) 14C ages.
A Preliminary Assessment of Age at Death Determination Using the Nuclear Weapons Testing 14C Activity of Dentine and Enamel
Authors: Cook Gordon T , Dunbar Elaine , Black Sue M , Xu Sheng
Published: July 2016

Calibration (using CALIBomb) of radiocarbon measurements made on the enamel of human teeth from people born during the nuclear era typically produce 2 possible age ranges that potentially reflect the period of tooth formation. These ranges correspond to periods before and after the 1963 atmospheric 14C maximum. Further measurements made on the collagen component of the combined dentine and cementum from the roots of the same teeth enable the appropriate age range to be selected. Using this range and the formation times for individual teeth, we estimated the year of birth of the individuals and compared these to the known dates of birth. The results were relatively accurate and confirmed those of a previous study by another research group. The present study demonstrates that it is possible to produce a good estimate of the year of birth from a single tooth.
Radiocarbon Dating of Soil Organic Matter Fractions in Andosols in Northern Ecuador
Authors: Tonneijck Femke H , van der Plicht Johannes , Jansen Boris , Verstraten Jacobus M , Hooghiemstra Henry
Published: July 2016

Volcanic ash soils (Andosols) may offer great opportunities for paleoecological studies, as suggested by their characteristic accumulation of organic matter (OM). However, understanding of the chronostratigraphy of soil organic matter (SOM) is required. Therefore, radiocarbon dating of SOM is necessary, but unfortunately not straightforward. Dating of fractions of SOM obtained by alkali-acid extraction is promising, but which fraction (humic acid or humin) renders the most accurate 14C dates is still subject to debate. To determine which fraction should be used for 14C dating of Andosols and to evaluate if the chronostratigraphy of SOM is suitable for paleoecological research, we measured 14C ages of both fractions and related calibrated ages to soil depth for Andosols in northern Ecuador. We compared the time frames covered by the Andosols with those of peat sequences nearby to provide independent evidence. Humic acid (HA) was significantly older than humin, except for the mineral soil samples just beneath a forest floor (organic horizons), where the opposite was true. In peat sections, 14C ages of HA and humin were equally accurate. In the soils, calibrated ages increased significantly with increasing depth. Age inversions and homogenization were not observed at the applied sampling distances. We conclude that in Andosols lacking a thick organic horizon, dating of HA renders the most accurate results, since humin was contaminated by roots. On the other hand, in mineral soil samples just beneath a forest floor, humin ages were more accurate because HA was then contaminated by younger HA illuviated from the organic horizons. Overall, the chronostratigraphy of SOM in the studied Andosols appears to be suitable for paleoecological research.
Society Islands (Central Eastern Polynesia) Chronology: 11 Radiocarbon Dates for the Late Prehistoric Expansion and Proto-Historic Periods in the ‘Opunohu Valley, Mo'Orea
Authors: Kahn Jennifer G
Published: July 2016

The chronology of residential site construction and occupation in the upper reaches of the ‘Opunohu Valley, Mo'orea, Central Eastern Polynesia, has been debated over the last 15 yr. This paper reports a suite of 11 radiocarbon age determinations from excavations at 5 house sites and a simple temple structure (marae). Direct accelerator mass spectrometry (AMS) dating of wood charcoal identified to short-lived taxa confirms site construction and occupation during the mid-15th to 17th centuries, supporting that maximal population density was in the centuries immediately prior to European contact. The study demonstrates that targeted dating of multiple structures within residential complexes allows for multiple phases of site construction and use to be discriminated. These data are critical for adequately assessing site contemporaneity and the development, maintenance, and expansion of residential groups and their house clusters through time.
Radiocarbon Laboratory at the National Autonomous University of Mexico: First Set of Samples and New 14C Internal Reference Material
Authors: Beramendi-Orosco Laura E , Gonzalez-Hernandez Galia , Urrutia-Fucugauchi Jaime , Morton-Bermea Ofelia
Published: July 2016

This contribution reports the first set of samples and the creation of an internal reference material at the recently opened Radiocarbon Laboratory at the National Autonomous University of Mexico (UNAM). Samples for the initial measurements were selected from archaeological and dating projects on Teotihuacán, one of the largest and best-studied Mesoamerican urban and ceremonial centers. The 14C dates were compared to results obtained by 2 other laboratories in order to assess the results obtained at UNAM and validate the adopted methodology. As part of the quality assurance protocol, an internal reference material was created that consists of charred wood from the Teotihuacán site with a 14C activity in the value range expected for samples from Mesoamerican archaeological sites. Results from 7 analyses have a mean of 1750 ± 16 BP (80.43 ± 0.16 pMC).
Anomalous Radiocarbon Ages Found in Campanian Ignimbrite Deposit of the Mediterranean Deep-Sea Core CT85-5
Authors: Hajdas Irka , Taricco Carla , Bonani Georges , Beer Jürg , Bernasconi Stefano M , Wacker Lukas
Published: July 2016

A detailed radiocarbon chronology has been established for the deep-sea core CT85-5 from the Tyrrhenian Sea. This chronology, which is based on the analysis of foraminifera shells, shows a set of reversed 14C ages for sediments deposited during the eruption of the Campanian Ignimbrite (∼40 ka cal BP). The anomalous young 14C ages coincide with elevated concentrations of 10Bc measured in the same core. Although reversals in 14C ages have been previously found in other records at 40 ka cal BP, such extreme changes have not been observed elsewhere. The enhancement in 14C concentration in CT85-5 sediments associated with the Campanian Ignimbrite is equivalent to an apparent age ∼15 ka younger than the age for the sediments deposited shortly before the eruption. Here, we present consistent results of repeated measurements showing no analytical problems that can explain the observed rapid changes in 14C of this particular record.
Residential Chronology, Household Subsistence, and the Emergence of Socioeconomic Territories in Leeward Kohala, Hawai'i Island
Authors: Field Julie S , Ladefoged Thegn N , Sharp Warren D , Kirch Patrick V
Published: July 2016

Previous research in leeward Kohala, Hawai'i Island, has determined that the Leeward Kohala Field System (LKFS), a vast agricultural zone covering ∼60 km2, developed between the 14th and 18th centuries AD. Additional analyses have documented the establishment of traditional socioeconomic territories, known as ahupua'a, in tandem with the expansion of the field system. This article further refines the chronology of human settlement and socioeconomic development in leeward Kohala through the analysis of deposits associated with prehistoric residences. Based upon survey and excavation, we present a chronology for Hawaiian household transition and economic development in 2 study areas of leeward Kohala, spanning the field system to the coast. Forty-nine radiocarbon dates from short-lived plant materials and 5 230Th dates on corals from residential and ritual features are synthesized into 3 temporal periods, which allow for comparison of residential size, distribution, number, and associated faunal materials from archaeological deposits. Changes in household composition and economy are suggested to have developed in tandem with the establishment of individual ahupua'a and land divisions within them, and the further development of agricultural production.
Assessing the Effect of Sterilization on the Radiocarbon Signature of Freshwater Dissolved Organic Carbon
Authors: Baker Andy , Gulliver Pauline , Ascough Phillipa , Roe Jessie , Bridgeman John
Published: July 2016

Radiocarbon analysis of freshwater dissolved organic carbon (DOC) involves substantial sample pretreatment, including an initial rotary evaporation stage necessary to concentrate large volumes of freshwater sample. This may lead to a health risk from the exposure to pathogens, and there is the additional concern that the warm conditions during the rotary evaporation stage may provide ideal growing conditions for some pathogens. To remove any pathogen risk in water samples, boiling or autoclaving can be undertaken. However, to date, no studies have been undertaken to investigate whether boiling will alter the 14C signature of dissolved organic carbon. Here, we analyze the effect of sterilization on 9 contrasting river water samples. Comparing filtered, filtered and boiled, and filtered and sterilized dissolved organic matter, we observe that both boiling and autoclaving increases the uncertainty associated with the 14C and 13C of DOC, that the 14C and 13C changes are not unidirectional, and that they are not related to original DOC composition. Neither sterilization method is recommended unless essential, in which instance we recommend a 3σ uncertainty on 14C and that the 13C is not considered representative of the original sample.
Water Column Profiles of Dissolved Inorganic Radiocarbon for the Kuroshio Region, Offshore of the Southern Japanese Coast
Authors: Tsuboi Tatsuya , Iwata Hiroshi , Wada Hideki , Matsuzaki Hiroyuki , Sohrin Rumi , Hiroe Yutaka , Ichikawa Tadafumi , Hidaka Kiyotaka , Watanabe Tomoo
Published: July 2016

We present the water column profiles (surface to 2000 m depth) for dissolved inorganic radiocarbon (14CDIC) from 2 stations in the Kuroshio region including the Kuroshio large meander (LM) of 2004–2005. Surprisingly, the Δ14CDIC value varied up to 125‰ in the intermediate layer, especially near 600 m depth. In addition, the Δ14CDIC value was approximately − 150‰ at 200 m depth at the northern station of Kuroshio in August 2005. This value is ∼100‰ less than other Δ14CDIC values for the same depth. In comparison, the Δ14CDIC water column profiles for the southern station of Kuroshio and GEOSECS station 224 decrease down to 600 m depth and were similar below 600 m depth. Our results suggest that strong upwelling associated with the Kuroshio LM has a powerful influence on the Δ14CDIC water column profiles in the study region.
Pushing the Precision Limit of 14C AMS
Authors: Steier Peter , Dellinger Franz , Kutschera Walter , Priller Alfred , Rom Werner , Maria Wild Eva
Published: July 2016

High precision for radiocarbon cannot be reached without profound insight into the various sources of uncertainty which only can be obtained from systematic investigations. In this paper, we present a whole series of investigations where in some cases 16O:17O:18O served as a substitute for 12C:13C:14C. This circumvents the disadvantages of event counting, providing more precise results in a much shorter time. As expected, not a single effect but a combination of many effects of similar importance were found to be limiting the precision.

We will discuss the influence of machine tuning and stability, isotope fractionation, beam current, space charge effects, sputter target geometry, and cratering. Refined measurement and data evaluation procedures allow one to overcome several of these limitations. Systematic measurements on FIRI-D wood show that a measurement precision of ±20 14C yr (1 σ) can be achieved for single-sputter targets.
The Keck Carbon Cycle AMS Laboratory, University of California, Irvine: Initial Operation and a Background Surprise
Authors: Southon John , Santos Guaciara , Druffel-Rodriguez Kevin , Druffel Ellen , Trumbore Sue , Xu Xiaomei , Griffin Sheila , Ali Shahla , Mazon Maya
Published: July 2016

A new radiocarbon accelerator mass spectrometry (AMS) laboratory for carbon cycle studies has been established at the University of California, Irvine. The 0.5MV AMS system was installed in mid-2002 and has operated routinely since October of that year. This paper briefly describes the spectrometer and summarizes lessons learned during the first year of operation. In the process of setting up the system, we identified and largely suppressed a previously unreported 14C AMS background: charge exchange tails from 14N beams derived from nitrogen-containing molecular ions produced near the entrance of the accelerator.
Direct Coupling of an Elemental Analyzer and a Hybrid Ion Source for AMS Measurements
Authors: Uhl Thomas , Kretschmer Wolfgang , Luppold Wolfgang , Scharf Andreas
Published: July 2016

The requests to measure many samples, and samples with very low carbon masses, make it necessary to develop new techniques in sample handling to accelerate sample preparation and to eliminate carbon contamination. Our 40 MC-SNICS was recently modified to a hybrid ion source. To run the hybrid ion source with a gas parameter, settings were studied and a gas handling system for the direct coupling of an elemental analyzer and a gas ion source was developed.
AMS 14C Dating of Iron Artifacts: Development and Application
Authors: Enami Hiroki , Nakamura Toshio , Oda Hirotaka , Yamada Tetsuya , Tsukamoto Toshio
Published: July 2016

We have developed a prototype carbon extraction system for accelerator mass spectrometry (AMS) radiocarbon dating of archaeological iron remains by combusting them with a RF induction furnace. We have also successfully tested and used a method of carbon extraction from iron using a CuCl2 solution. Modifications to our carbon extraction systems and methods provide us acceptable performances; carbon yield is normally around 80% and the 14C background level is as low as 42–48 ka BP in 14C apparent age. We have also conducted an iron refining experiment to examine the sources for carbon 14C age derived from iron, using established AMS 14C dating and carbon extraction systems. Our refining experiment was conducted on iron slag, which are by-products formed during iron smelting methods in the 7th century AD, and using modern charcoal as fuel. The aim of the experiment was to determine whether original carbon characteristics in the original iron materials would be preserved, or if the carbon signature would be replaced to some degree by the modern charcoal. AMS 14C measurements on the refined iron yielded 14C ages equivalent to those of the modern charcoal fuel. The result indicates that the original carbon signatures in the iron slag from 7th century production was replaced completely by modern carbon used in our experiment. The experiment confirms the assumption that 14C ages on iron products are associated with the fuel source of the iron smelting or refining process. We also report on the dating of iron slag materials excavated from the Gennaitouge iron smelting site, where 14C dates were consistent with the age of the site estimated by archaeological evidence.
A Review of the Evidence for Extinction Chronologies for Five Species of Upper Pleistocene Megafauna in Siberia
Authors: Orlova Lyobov A , Kuzmin Yaroslav V , Dementiev Vyacheslav N
Published: July 2016

A review of the radiocarbon chronology of some late Upper Pleistocene mammals from Siberia is presented. Previously published data has been supplemented by new 14C dates for 5 species (woolly mammoth, woolly rhinoceros, bison, horse, and muskox) to reconstruct chronological extinction patterns. The final extinction of woolly rhinoceros and bison in Siberia can be dated to approximately 11,000–9700 BP, but some megafaunal species (woolly mammoth, horse, and muskox) survived into the Late Holocene, about 3700–2200 BP.
Chronology of Prehistoric Cultural Complexes of Sakhalin Island (Russian Far East)
Authors: Kuzmin Yaroslav V , Vasilevski Alexander A , Gorbunov Sergei V , Burr G S , Jull A J Timothy , Orlova Lyobov A , Shubina Olga A
Published: July 2016

A chronological framework for the prehistoric cultural complexes of Sakhalin Island is presented based on 160 radiocarbon dates from 74 sites. The earliest 14C-dated site, Ogonki 5, corresponds to the Upper Paleolithic, about 19,500–17,800 BP. According to the 14C data, since about 8800 BP, there is a continuous sequence of Neolithic, Early Iron Age, and Medieval complexes. The Neolithic existed during approximately 8800–2800 BP. Transitional Neolithic-Early Iron Age complexes are dated to about 2800–2300 BP. The Early Iron Age may be dated to about 2500–1300 BP. The Middle Ages period is dated to approximately 1300–300 BP (VII–XVII centuries AD).
Dating of Total Soil Organic Matter Used in Kurgan Studies
Authors: Molnár M , Joó K , Barczi A , Szántó Zs , Futó I , Palcsu L , Rinyu L
Published: July 2016

We investigated Csípo-halom, one of the kurgans that served as a burial place in the Hortobágy area of the Hungarian Great Plain. For pedological description and other studies of the protected mound and its surroundings, only a few monitoring drillings were permitted to get soil samples. On the basis of morphological and visual studies, the structure and layers of the mound were reconstructed. The Laboratory of Environmental Studies of the Institute of Nuclear Research at the Hungarian Academy of Sciences (INR/HAS) performed radiocarbon measurements of soil samples, applying a bulk combustion pretreatment method. The measured 14C ages of soil samples from reference points, such as the top layer of the mound, the center of mound body, the base layer of the mound, the near surroundings, and the distant surroundings, are in good agreement with the preliminary archaeological concept for this field and give substantial information about the rate of soil generation processes in this area.