bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractionation Corrections in Radiocarbon Dating
Authors: Wigley T M L , Muller A B
Published: July 2016

Recent experimental work has suggested that the relative fractionation of 14C to 13C may differ from the accepted value of b = 2. In order to explore the implications of this possibility, the standard formulae for correcting radiocarbon dates for fractionation effects are rederived, but without making any of the usual assumptions or approximations. A generalized dating equation

is derived (where ASN and AON are normalized sample and standard activities, β is a factor which reflects changes in atmospheric 13C and 14C content, {RST(o)/RST}b accounts for post-depositional changes in sample 13C ratio, and tcal is calendar age in years before ad 1950. The errors in calculated ages which might arise from different b values are estimated and shown to be small relative to other dating uncertainties. The effect of b ≠ 2 may be important in the calibration of radiocarbon dates using tree-ring samples of known age. A theoretical analysis suggests that b ≠ 2 effects may result in a correlation between age anomaly (ie, the difference between radiocarbon age and calendar age) and sample 13C data. However, an analysis of published data reveals no meaningful correlation. This result, while not eliminating the possibility that b ≠ 2, highlights its unimportance even in this high-precision application of radiocarbon dating.
Marine Resources Research Institute Radiocarbon Dates III
Authors: Mathews Thomas D
Published: July 2016

Samples in this paper are a continuation of the Florida geologic samples, reported earlier (R, 1978, v 20, p 436–440). Each specimen analyzed in this list was a carbonate shell. All dates are from single shells as opposed to means of multiple shell samples.
Scottish Universities Research and Reactor Centre Radiocarbon Measurements IV
Authors: Harkness D D
Published: July 2016

Results reported here are for samples of geologic or geographic context completed during the period 1975 to 1978.
Radiocarbon Dating of Single Compounds Isolated from Pottery Cooking Vessel Residues
Authors: Stott A W , Berstan R , Evershed P , Hedges R E M , Bronk Ramsey C , Humm M J
Published: July 2016

We have developed and demonstrated a practical methodology for dating specific compounds (and octade-canoic or stearic acid—C18:0—in particular) from the lipid material surviving in archaeological cooking pots. Such compounds may be extracted from about 10 g of cooking potsherd, and, after derivatization, can be purified by gas chromatography. To obtain sufficient material for precise dating repetitive, accumulating, GC separation is necessary. Throughout the 6000-year period studied, and over a variety of site environments within England, dates on C18:0 show no apparent systematic error, but do have a greater variability than can be explained by the errors due to the separation chemistry and measurement process alone. This variability is as yet unexplained. Dates on C16:0 show greater variability and a systematic error of approximately 100-150 years too young, and it is possible that this is due to contamination from the burial environment. Further work should clarify this.
Preparation of Graphite Targets in the Gliwice Radiocarbon Laboratory for AMS14C Dating
Authors: Czernik Justyna , Goslar Tomasz
Published: July 2016

A line for preparation of graphite targets for accelerator mass spectrometry (AMS) radiocarbon dating has been built in the Gliwice14C Laboratory. The AMS14C measurements of our targets are performed in the Leibniz-Labor für Altersbestimmung, Kiel, Germany. The quality of our line has been tested in two series of AMS14C measurements of background and Ox-II standard samples and by measurements of the amount of CO2released during combustion of sample-free quartz tubes. Most background contamination in the first series was introduced during combustion, which has been greatly reduced by baking quartz tubes vacuum-sealed with CuO and Ag. The residual contamination (ca. 1.5 μg C) seems to come mostly from the quartz tubes themselves. At present, most of the contamination of the background is introduced during graphitization. The reproducibility of background preparations is satisfactory, especially for samples larger than 1.5 mg, when it is better than ± 0.09 pMC. Despite still significant contamination with low-14C carbon during the graphitization process (corresponding to 1.2 ± 0.2% of14C-free carbon), the good reproducibility of the results allows us to use our line in routine14C dating.
Automatic AMS Sample Combustion and CO2 Collection
Authors: Aerts-Bijma A T , van der Plicht J , Meijer H A J
Published: July 2016

In Groningen, all organic samples for accelerator mass spectrometry (AMS) are combusted in an automatic Elemental Analyzer, coupled to an Isotope Ratio Mass Spectrometer and Cryogenic Trapping System. The Gas Chromatographic (GC) column, part of the Elemental Analyzer system, appeared to be the main cause for memory effects. Therefore we modified the Elemental Analyzer, such that the trapped CO2 no longer passed the GC column. Our system modification reduced the memory effect significantly, as shown by lower radiocarbon concentration values for anthracite backgrounds, and a much smaller spread in these values. Our modified system can perform up to 40 combustions unattended in about 6 hr.
Converting AMS Data to Radiocarbon Values: Considerations and Conventions
Authors: McNichol A P , Jull A J T , Burr G S
Published: July 2016

We summarize the basic operation of accelerator mass spectrometry (AMS) systems used to measure radiocarbon and discuss the calculations used to convert AMS output to 14C data.
A Database System for Geochemical, Isotope Hydrological, and Geochronological Laboratories
Authors: Suckow Axel , Dumke Ingolf
Published: July 2016

We present a data model designed for laboratories in which many different methods are used. The main feature of the model is the recursive relationships of data records in the subsample table. This makes it possible to model all steps from the preparation of the sample to the final value and enables the raw data to be stored together with the final values, even if many preparation steps or many subsamples are involved. We show ways to adopt this basic model to laboratories with many years of data. The data model is extended to include laboratory records and attribute data, e.g. the geographical coordinates of the sampling site or links to the various projects for which the samples are used.
‘Wiggle Matching’ Radiocarbon Dates
Authors: Bronk Ramsey C , van der Plicht J , Weninger B
Published: July 2016

This paper covers three different methods of matching radiocarbon dates to the ‘wiggles’ of the calibration curve in those situations where the age difference between the 14C dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi-squared fit of the 14C data to the 14C curve. This gives the calendar date where the data fit best and allows tests of how good the fit is. The only drawback of this method is that it is difficult to ascertain the uncertainty in the date found in this way. An extension of this technique uses a Monte-Carlo simulation to sample possible 14C concentrations consistent with the measurement made and for each of these possibilities performs a Chi-squared fit. This method yields a distribution of values in the calendrical time-scale, from which the overall dating uncertainty can be derived. A third, rather different approach, based on Bayesian statistics, calculates the relative likelihood of each possible calendar year fit. This can then be used to calculate a range of most likely dates in a similar way to the probability method of 14C calibration. The theories underlying all three methods are discussed in this paper and a comparison made for the fitting of specific model sequences. All three methods are found to give consistent results and the application of any one of them depends on the nature of the scientific question being addressed.
14C Wiggle-Match Dating in High-Resolution Sea-Level Research
Authors: van de Plassche O , Edwards R J , van der Borg K , de Jong A F M
Published: July 2016

Comparison of two sets of marsh-accumulation records from each of three Connecticut (USA) salt marshes, one based on individually calibrated dates and the other on wiggle-match dating of the same series of dates, shows that wiggle-match dating results in more precise and objective reconstructions of longer-term (102–103 yr) changes in accumulation rate. On (sub-)century time scales, wiggle-match dating can reveal steps in the calibrated marsh-accumulation envelope as artefacts of the calibration curve, but may also leave real short-term changes in accumulation rate undetected. Wiggle-matches are non-unique, being dependent on the number, quality and distribution of radiocarbon dates in a sequence, how a series of dates is subdivided into groups (representing intervals of uniform accumulation rate), and what is considered a “best match”. Samples from the studied salt-marsh deposits required no correction for reservoir effects prior to calibration.
14C Wiggle Matching of the ‘Floating’ Tree-Ring Chronology from the Altai Mountains, Southern Siberia: the Ulandryk-4 Case Study
Authors: Slusarenko I Y , Christen J A , Orlova L A , Kuzmin Y V , Burr G S
Published: July 2016

The Bayesian approach to calibration of radiocarbon dates was used to wiggle-match the “floating” tree-ring chronology from a Pazyryk culture (Scythian-type complex from Sayan-Altai Mountain system, southern Siberia) burial ground in order to estimate the calendar age of its construction. Seventeen bidecadal tree-ring samples were 14C dated with high precision (±20–30 yr). The results of wiggle-matching show that the Pazyryk-type burial mounds in the southern Altai Mountains were created in the first part of 3rd century BC.
Radiocarbon Reservoir Correction Ages in the Peter the Great Gulf, Sea of Japan, and Eastern Coast of the Kunashir, Southern Kuriles (Northwestern Pacific)
Authors: Kuzmin Yaroslav V , Burr G S , Timothy Jull A J
Published: July 2016

The radiocarbon reservoir age correction values (R) for the Russian Far East are estimated as 370 ± 26 yr for the northwestern Sea of Japan, and 711 ± 46 yr for the southern Kurile Islands.
Preliminary Estimate of the Reservoir Age in the Lagoon of Venice
Authors: Zoppi U , Albani A , Ammerman A J , Hua Q , Lawson E M , Serandrei Barbero R
Published: July 2016

The Lagoon of Venice was formed about 6000 years ago due to the marine transgression associated with the late Pleistocene sea level rise. Already by the time of the Republic of Venice (727–1797 AD) it was recognized that the future of the city and its many historical buildings was strongly correlated with the future of the lagoon itself. During the centuries many engineering projects such as modification of the fluvial systems, construction of coastal barriers, and dredging of navigation channels were carried out to preserve the lagoonal environment. The present-day lagoon is the result of all these processes and covers an area of 540 km2 with an average depth of 0.6 m. A series of radiocarbon age determinations carried out on material obtained from cores collected in the Lagoon of Venice indicate within the sedimentary units the existence of a number of discontinuities and slumping events due to the highly active lagoonal environment. The evaluation of data obtained from a variety of different materials—both terrestrial and marine—allowed us to determine for the first time the marine reservoir effect in the lagoon of Venice. The discussion includes a comparison with other relevant measurements and a possible explanation to the relatively high reservoir age (1200–1300 yr).
Settlement Patterns in the Southern Levant Deserts During the 6th–3rd Millennia BC: a Revision Based on 14C Dating
Authors: Avner Uzi , Carmi Israel
Published: July 2016

Archaeological surveys conducted in the Negev and Sinai during the 20th century were commonly interpreted as representing short settlement periods interrupted by long gaps. The time factor was usually based on archaeological estimates rather than comprehensive physical dating. For example, the perceived age and time duration of “hole-mouth” pottery sherds and tabular flint scrapers became a source of circular reasoning to “date” sites and their “duration.” Thus, desert sites became to be perceived as temporary, seasonal, short-lived, while the cultures of desert populations were somehow undervalued. However, radiocarbon dating of desert sites from the Late Neolithic to the Early Bronze Age IV presents a very different scenario. The deserts of the Southern Levant exhibit a full sequence of settlement, a longer life span of individual sites, and a higher level of activity and creativity of the desert people. This paper describes the controversy and presents the 14C data that form the basis for the revised view.
Excavations at Ma'layba and Sabir, Republic of Yemen: Radiocarbon Datings in the Period 1900 to 800 cal BC
Authors: Görsdorf Jochen , Vogt Burkhardt
Published: July 2016

The Bronze and Iron Age cultures in Yemen have no parallels to the well dated cultures in the Syro-Palestinian region. Radiocarbon datings are therefore exceptionally important for the Yemenite archaeological excavation sites of Ma'layba and Sabir, the latter being the largest excavation site of the Sabir culture. Dating series were done in order to determine the architectural development of the sites and find time marks for the ceramic development. Sample materials were dated from the 2nd and 1st millennium before Christ. The 14C dating results allow statements about the cultural development in Ma'layba and Sabir as well as a comparison with the development of other regions in the surrounding, independent of only sparse available archaeological parallels.
High-Accuracy 14C Measurements for Atmospheric CO2 Samples by AMS
Authors: Meijer H A J , Pertuisot M H , van der Plicht J
Published: July 2016

In this paper, we investigate how to achieve high-accuracy radiocarbon measurements by accelerator mass spectrometry (AMS) and present measurement series (performed on archived CO2) of 14CO2 between 1985 and 1991 for Point Barrow (Alaska) and the South Pole. We report in detail the measurement plan, the error sources, and the calibration scheme that enabled us to reach a combined uncertainty of better than ±3%. The δ13C correction and a suggestion for a span (or 2-point) calibration for the 14C scale are discussed in detail. In addition, we report new, accurate values for the calibration and reference materials Ox2 and IAEA-C6 with respect to Oxl. The atmospheric 14CO2 records (1985–1991) are presented as well and are compared with other existing records for that period. The Point Barrow record agrees very well with the existing Fruholmen (northern Norway) record from the same latitude. The South Pole record shows a small seasonal cycle but with an extreme phase with a maximum on January 1st (±13 days). Together with its generally elevated 14C level compared to the Neumayer record (coastal Antarctica), this makes our South Pole data set a valuable additional source of information for global carbon cycle modeling using 14CO2 as a constraint.
Radioactive Graphite Dispersion in the Environment in the Vicinity of the Chernobyl Nuclear Power Plant
Authors: Buzinny Michael
Published: July 2016

This paper estimates the radioactive graphite dispersion on the land surface (forest litter and soil) as a result of the Chernobyl Nuclear Power Plant (NPP) release. Graphite mass was calculated using an estimated average concentration of 2.5 × 107 Bq/kgC (carbon). The sample collection method, sample origin and its mass, and sample preparation procedure used for preparation of benzene were taken into account to obtain the optimum sensitivity of the method. Thus, the sensitivity of the corresponding method for graphite detection in forest litter was estimated to be 0.2 mg/m2. All analyses gave a range of deposited graphite from 0.12 to 52.6 mg/m2. The maximum value was observed at a site located 9 km west of the Chernobyl NPP. The results of the study indicate the importance of studying the upper layer of soil (0–5 cm) in addition to the lower layer of forest litter.
ENEA Radiocarbon Measurements II
Authors: Magnani Giuseppe , Bartolomei Paolo , Torretta Teresa La , Marino Ernesto Claudio
Published: July 2016

This paper includes determinations of geological samples coming from the Emilia Romagna region (northern Italy) performed at the ENEA Radiocarbon Laboratory. These analyses were executed as part of the Geological Cartography (CARG) project aimed to realize a new Italian Geological Map.
Using a Gas Ion Source for Radiocarbon AMS and GC-AMS
Authors: Bronk Ramsey Christopher , Ditchfield Peter , Humm Martin
Published: July 2016

This paper reports on the performance of a new method of sample injection using the High Voltage Engineering Europa (HVEE) SO-110 ion source jointly developed between HVEE and Oxford. In order to use this source, we have developed a new gas handling system which works on the direct injection of carbon dioxide mixed into a continuous flow of helium. Preliminary work has also been carried out on online gas chromatography-accelerator mass spectrometry (GC-AMS). In this application, a GC is directly coupled to the AMS system using a GC-IRMS combustion interface and Nafion™ drier. We show here results for the measurement of natural abundance in separated compounds with good peak separation and precisions of about 10%. This type of system should be ideal for source apportionment studies, biomedical, and other similar work where high precision is not required but where sample sizes are very low.
Capabilities of the New SUERC 5MV AMS Facility for 14C Dating
Authors: Xu S , Anderson R , Bryant C , Cook G T , Dougans A , Freeman S , Naysmith P , Schnabel C , Scott E M
Published: July 2016

A new National Electrostatic Corporation (NEC) 5MV accelerator mass spectrometer became operational at the Scottish Universities Environmental Research Centre (SUERC) in July 2002. It has 2 Cs sputter negative ion sources: a 134-sample source (S1) for the routine measurement of all species, and a hybrid source (S2) with 40 spaces for radiocarbon measurements with either graphite or CO2 samples. A number of performance tests on graphite samples have been carried out on both sources. A precison of better than 0.3% is feasible for modern samples on a routine basis. The 14C background of the machine and the graphite preparation process blank are 0.04 ± 0.01 and 0.16 ± 0.05 pMC, respectively, indicating that 14C dating back to ~50 kyr BP is possible. The normalized 14C values for a series of reference materials agree well with the IAEA, TIRI, and FIRI consensus values. Routine measurement of 14C has been underway since May 2003. Preliminary results of performance tests on the CO2 gas ion source are also reported.
A Pretreatment Procedure for the AMS Radiocarbon Dating of Sub-Fossil Insect Remains
Authors: Tripp J A , Higham T F G , Hedges R E M
Published: July 2016

Two pretreatment methods for accelerator mass spectrometry (AMS) dating of insect remains were explored. One method involves a simple acid wash that removes carbonate, while the other is based on the industrial purification of chitin and results in isolation of polymeric chitosan. No contamination is observed from Maillard reactions during the deacetylation reaction used to isolate the chitosan. The methods were tested on Coleoptera samples from two Roman Britain sites. Our results demonstrate that both methods produce acceptable AMS dates that correspond well to the expected age of the deposits from which they came.
Preliminary Results for the Extraction and Measurement of Cosmogenic in Situ 14C from Quartz
Authors: Naysmith P , Cook G T , Phillips W M , Lifton N A , Anderson R
Published: July 2016

Radiocarbon is produced within minerals at the earth's surface (in situ production) by a number of spallation reactions. Its relatively short half-life of 5730 yr provides us with a unique cosmogenic nuclide tool for the measurement of rapid erosion rates (>10−3 cm yr−1) and events occurring over the past 25 kyr. At SUERC, we have designed and built a vacuum system to extract 14C from quartz which is based on a system developed at the University of Arizona. This system uses resistance heating of samples to a temperature of approximately 1100° in the presence of lithium metaborate (LiBO2) to dissolve the quartz and liberate any carbon present. During extraction, the carbon is oxidized to CO2 in an O2 atmosphere so that it may be collected cryogenically. The CO2 is subsequently purified and converted to graphite for accelerator mass spectrometry (AMS) measurement. One of the biggest problems in measuring in situ 14C is establishing a low and reproducible system blank and efficient extraction of the in situ 14C component. Here, we present initial data for 14C-free CO2, derived from geological carbonate and added to the vacuum system to determine the system blank. Shielded quartz samples (which should be 14C free) and a surface quartz sample routinely analyzed at the University of Arizona were also analyzed at SUERC, and the data compared with values derived from the University of Arizona system.
Radiocarbon Dating of Sopot Culture Sites (Late Neolithic) in Eastern Croatia
Authors: Obelić Bogomil , Krznarić Škrivanko Marija , Marijan Boško , Krajcar Bronić Ines
Published: July 2016

The results of radiocarbon dating of several Late Neolithic archaeological sites in Slavonia, eastern Croatia, are presented. According to the archaeological findings, the sites belong to the Sopot culture. Stages I-B, II-A, II-B, and III were identified at the eponym site Sopot near Vinkovci, stages I-B and II at the site Dubovo-Košno near Županja, while findings for other investigated sites (Herrmann's Vineyard near Osijek, Mandek's Vineyard from Otok, Privlaka near Vinkovci, and Slavča near Nova Gradiška) were placed to phases II and III.14C results place the I-B stage to the period 5480–5070 cal BC, stage II-A to 5030–4770 cal BC, stage II-B to 4800–4250 cal BC, and phase III to 4340–3790 cal BC. These dates were compared to those obtained for other Late Neolithic cultures in the Pannonian Valley. The results confirmed the Protolengyel character of Sopot culture.
The End of the Chalcolithic Period in the South Jordan Valley: New 14C Determinations from Teleilat Ghassul, Jordan
Authors: Bourke Stephen , Zoppi Ugo , Meadows John , Hua Quan , Gibbins Samantha
Published: July 2016

This article reports on 12 new accelerator mass spectrometry (AMS) dates from the latest phases of the Chalcolithic period occupation (late 5th millennium cal BC) at Teleilat Ghassul, type site for the south Levantine Ghassulian Chalcolithic culture. The new AMS dates from Teleilat Ghassul favor an amendment to a previous suggestion (Bourke et al. 2001), that all significant occupation at the site had ceased by 4000/3900 cal BC. This end-date should now be amended to 3900/3800 cal BC. Follow-up statistical modelling sourced to published 14C data drawn from a wide selection of south Levantine Chalcolithic period sites (Bourke 2001; Burton and Levy 2001) raises the possibility that Chalcolithic period occupation had ceased at virtually all major centers by 3800/3700 cal BC. This, in turn, suggests that the new data bearing on the end-date for occupation at Teleilat Ghassul may reflect a more widespread horizon of abandonment in the southern Levant.
Radiocarbon Dating of Kohitsugire (Paper Fragments) Attributed to Japanese Calligraphists in the Heian–Kamakura Period
Authors: Oda Hirotaka , Ikeda Kazuomi , Masuda Takashi , Nakamura Toshio
Published: July 2016

A kohitsugire is a paper fragment from an old manuscript written mainly in the Heian and Kamakura periods. Although they contain significant information for historical, literary, and paleographical study, because of their antique handwriting and description of historical incidents, there are many copies and counterfeits written several centuries later. In this study, radiocarbon ages of kohitsugire were measured by accelerator mass spectrometry (AMS). On the kohitsugire attributed to the famous calligraphists in the Kamakura period (Fujiwara no Sadaie and Prince Munetaka), 14C dating indicated that they were not genuine and should be excluded from the materials for study of the calligraphists. Calibrated 14C ages of the kohitsugire attributed to Fujiwara no Yukinari indicated the middle Heian period. This calligraphy was written on Tobikumogami paper, which has a billowing cloud pattern decorated with indigo-blue-dyed fiber. Although it was commonly accepted that the Tobikumogami is peculiar to the middle 11th to early 12th century, the results from 14C dating also suggested that the origin of the Tobikumogami would date back to the last of the 10th or the early 11th century, when Fujiwara no Yukinari flourished as a calligraphist. Calibrated 14C ages of the kohitsugire attributed to Nijo Tameuji and Reizei Tamesuke showed that they are fragments of old manuscripts describing lost tales and were written in the 13th–14th century. Consequently, 14C dating clarified the existence of ancient tales which had been unknown and indicated their worth as a material for the study of classical Japanese literature.
Further Investigations on 14C Dating of Calcareous Tufa
Authors: Pazdur Anna , Pazdur Mieczysław F
Published: July 2016

Systematic studies on 14C dating of tufa profiles in southern Poland have resulted in developing a simple phenomenological model which enables us to estimate the reservoir correction factor of 14C dates of individual carbonate samples. We made further studies to test model assumptions and to verify relationships between the value of reservoir correction factor TR and 13C content of tufa carbonate. Two new study sites, Rudawa and Szklarka, are close to previously studied sites. Four tufa samples with associated organic fraction from ca 2000m asl in South America (Peruvian Andes) were measured to test the possible application of the developed model to tufas in different geochemical and climatic environments. Finally, a series of calcareous tufa samples from the Villers-devant-Orval profile (Belgium) were dated, although no direct comparison with organic matter dates is available for this profile.
Operation of the Harwell UK 14C Data Base and its Expansion Through Data Exchange with Other Laboratories
Authors: Walker A J , Otlet R L , Housley R A , van der Plicht Johannes
Published: July 2016

The use of computer data bases for storage and retrieval of 14C data is a logical application for the rapidly expanding numbers of 14C determinations. Harwell has established a data base for all samples originating from sites in the United Kingdom and Eire. The core of the data is the Council for British Archaeology's published Index of Radiocarbon Dates which we are expanding to include all Harwell UK dates released for publication by the submitters plus dates from other laboratories both within and outside the UK. As a demonstration of the feasibility of direct database-to-database communication, cooperation has been sought from Groningen and Oxford to transfer computer files containing 14C results for UK sites. Neither of these laboratories use the same system as Harwell for their in-house data base and this exercise highlights the importance of a transfer language for both the national and international schemes as it is no longer practical to carry out such procedures through keyboard typing.
Special Report from the Glasgow Intercomparison Workshop on Quality Control and Assurance
Authors: Mook Willem G
Published: July 2016

The results of the Glasgow Intercomparison Project and discussions about ways to increase a laboratory's quality as well as an archaeologist's confidence led to a general agreement at the Workshop about the outline of a procedure for Quality Control and Assurance. The scheme is primarily based on proposals presented by Dr Austin Long, University of Arizona, Dr Roberto Gonfiantini of the International Atomic Energy Agency and our Glasgow hosts. It consists of three elements:
Museo de la Plata Radiocarbon Measurements II
Authors: Figini Anibal J , Carbonari Jorge E , Huarte Roberto A
Published: July 2016

The 14C measurements reported here were made between 1983 and 1987. Sample pretreatment and date calculations were previously reported (Figini et al 1984). The method employed, liquid scintillation counting, was previously described (Huarte & Figini 1988). No 13C/12C ratios were measured and results were not corrected for 13C fractionation and/or reservoir effect. Descriptions, comments and references to publications are based on information supplied by submitters.
University of Wisconsin Radiocarbon Dates XXVI
Authors: Steventon Raymond L , Kutzbach John E
Published: July 2016

Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists (Bender, Bryson & Baerreis 1965; Steventon & Kutzbach 1986). Except as otherwise indicated, wood, charcoal and peat samples are pretreated with dilute NaOH-NA4P2O7and dilute H3PO4before conversion to counting gas methane; when noted, marls and lake cores are treated with acid only. Very calcareous materials are treated with HCL instead of H3PO4.
University of Barcelona Radiocarbon Dates I
Authors: Mestres J. S. , Rauret Gemma , Garcia J. F.
Published: July 2016

The Radiocarbon Laboratory at the University of Barcelona began its serial measurements in 1985. The following list contains dates obtained between 1985 and 1987. Both archaeological and geological samples were dated.

The measurement technique we use is liquid scintillation counting of benzene. A previous paper (Mestres, García & Rauret 1991) describes sample pretreatment, synthesis and counting protocols and equipment.
Radiocarbon Chronology of Late Glacial and Holocene Sedimentation and Water-Level Changes in the Area of the Gościąż Lake Basin
Authors: Pazdur Anna , Pazdur M. F. , Goslar Tomasz , Wicik Bogumił , Arnold Maurice
Published: July 2016

We obtained 14C ages on samples of lake marl and other sediments from cores taken in Gościąż Lake and its environs. Comparison of 14C dates of bulk samples of laminated sediment with varve chronology and available AMS dates of terrestrial macrofossils indicates a reservoir correction of 2000 ± 120 yr for the basal series of lake sediments. 14C dates obtained on peat layers underlying the oldest lacustrine sediments in Gościąż and other lakes consistently locate the beginning of organogenic sedimentation in this area at ca. 13 ka bp. We distinguished three periods of lacustrine gyttja sedimentation in cores taken in Gościąż and adjacent lakes: 11.8–10.2 ka, 8–7 ka and 2.7–2.1 ka bp. From the 14C dates of lithological boundaries in these cores, we reconstruct a pattern of lake-level changes during the last 12 ka, remarkably similar to Swedish lakes and generally agreeing with available records from European and American lakes. The behavior of Gościąż Lake during the last 12 ka fairly well reflects global climate changes in the temperate zone during the Late Glacial and Holocene periods.
Radiocarbon and Uranium-Series Dating of the Plitvice Lakes Travertines
Authors: Srdoč Dušan , Osmond J. K. , Horvatinčić Nada , Dabous Adel A. , Obelić Bogomil
Published: July 2016

Radiocarbon and uranium-series ages of the calcareous deposits of the Plitvice Lakes show that travertines were deposited during three warm, humid, interglacial oxygen isotope stages. According to our measurements, only calcite crystals or crystal aggregates represent reliable material for both 230Th/234U and 234U/238/U dating. Compact old travertine in the form of sandstone is less reliable; it can be dated by both methods provided that its detrital contamination is not significant, demonstrated by very low 14C activity (< 1.5–2.0 pMC) and a high 230Th/232Th ratio. Old porous travertine contaminated with recent carbonates and Th-bearing clay (pMC > 5, 230Th/232Th < 5) gives erroneous results by both methods. Stage 1 (Holocene) deposition is shown primarily by 14C dating corroborated by sedimentological and palynologic studies as well as by both 230Th/234U and 234U/238U disequilibrium methods. The intensive growth of travertine barriers coincided with significant climate warming in the Holocene. Stage 5 deposition is confirmed by the 230Th/234U dating of crystalline calcite aggregates embedded in the travertine matrix and by concordant 230Th/234U and 234U/238U ages, assuming that the 234U/238U activity ratio of 1.88 observed in modern streams and in Holocene deposits can be extended to past epochs. The travertine deposition period was very short, peaking ca. 120 ± 10 ka bp. Stage 11 deposition is indicated by 234U/238U dating only, the period being within the 234U decay range, but not that of 230Th. Stage 11 travertine was deposited ca. 420 ± 50 ka bp. We did not find travertine samples with U-series ages indicating a growth period during relatively warm Stages 7 and 9; due to the scarcity of old travertine outcrops, these and possibly other stages cannot be excluded on the basis of presented data. All of these isotopic dating results concur with the field relation of the travertine complex of the Plitvice Lakes.
Further Attempts at Dating the Palynological Sequence of the Hula L07 Core, Upper Jordan Valley, Israel
Authors: Weinstein-Evron M , Vogel J C , Kronfeld J
Published: July 2016

The palynological sequence of the Hula L07 core was previously correlated with the global oxygen isotope stages 3–5, based on a radiocarbon age determination and comparison with other Levantine paleoclimatological curves. An attempt was made to validate this correlation with Th/U dating. Unlike typical European peat, which is acidic, the soil pH of the Hula peat is mildly basic. Not only does this contribute to the oxidation of palynomorphs, but it also helps to preserve the carbonate material that can be a variable mixture of allogenic, endogenic, and authigenic components. Each component may represent a different degree of uranium series disequilibrium. The thorium (232Th) concentrations of the carbonate are low. Total digestion or acid leach of the sample may not always enable the proper correction for initial thorium. The dating derived from a NaOH-extraction of the organic material, while giving apparently better ages, also suffers from the presence of the carbonate admixture. It appears that, while 14C dating can be considered suitable for the younger portions of the core, techniques based upon the U-series may not be as efficacious in dating this important record of climatic change.
Radiocarbon Studies of Peat Bogs: an Investigation of South Kamchatka Volcanoes and Upper Volga Archeological Sites
Authors: Zaretskaia N E , Ponomareva V V , Sulerzhitsky L D , Zhilin M G
Published: July 2016

We have undertaken extensive programs of natural radiocarbon measurement to date the evidence for various events buried in peat bogs. Two case studies are described here: 1) the chronological reconstruction of South Kamchatka volcanic eruptions and, 2) investigation of multi-layered archeological sites in the Upper Volga River Basin. Studies of sample composition and peat taphonomy allowed us to determine the source of 14C age deviations and to reconstruct the environmental history of organic matter accumulation. Data sets, obtained from different types of peat bog and containing traces of these Holocene events, are discussed.
New Data on Chronology of Landscape-Paleoclimatic Stages in Northwestern Russia During the Late Glacial and Holocene
Authors: Arslanov Kh A , Savelieva L A , Klimanov V A , Chernov S B , Maksimov F E , Tertychnaya T V , Subetto D A
Published: July 2016

Two lake and bog sediments have been thoroughly studied using palynological and radiocarbon dating methods. These are the Lembolovskoye Lake section located in the southern part of the Karelian Ithmus and the Mshinskoye bog section located in the southwestern part of the Leningrad province. The data obtained allow us to reconstruct the main features of the vegetation cover evolution, the chronology for the appearance and a real distribution of the main arboreal species from the south of the Leningrad province to the north, and to construct curves of the paleoclimate parameter changes for the area under study. Thirty-six 14C dates were obtained for the Lembolovskoye Lake section (7 m thick). According to those dates, the organic gyttja formation in the lake began 9870 ± 170 BP. Spore-pollen spectra with high percentage of herbs, arborescent, and shrub-birch dated back to the Younger Dryas were found out in clay layers at a depth of 6.5 m. An appearance of spruce and alder pollen is dated at 6860 ± 120 and 7510 ± 150 BP, respectively. The maximal percentage of broad-leaved species falls on the first half of the Atlantic (AT-1). Thirty-two dates were obtained for the Mshinskoye bog section (6 m thick): from 60 : 70 to 9520 ± 170 BP (the last date fixed the beginning of peat formation); 12 palinozones from the Preboreal to the Subatantic were recognized there. The spruce and alder pollen began to appear 7520 ±110 and 7670 ± 130 BP, respectively. The maximal amount of broad-leaved species is observed at 4690 ± 80 BP. The detailed reconstruction of changes in vegetation communities during the Late Glacial and Holocene was correlated with paleoclimatic characteristics, which have been recontructed for the sections under study by using the information from a statistical method of spore-pollen data processing.
Dating of Biodeposits of Oxalates at theArc De Beràin Tarragona, Spain
Authors: Girbal J , Prada J L , Rocabayera R , Argemí M
Published: July 2016

This research stems from an earlier study of the lichen covering with oxalate deposits at theArc de Beràmonument. The initial objective of dating these biodeposits opened up other questions concerning the structure of these deposits and how they were formed. Some dating results gave an absolute age greater than the monument itself, which posed various hypotheses on the possible ageing mechanisms.
Late Holocene Climatic Change in the Balkans: Speleothem Isotopic Data from Serbia
Authors: Kacanski Aleksander , Carmi Israel , Shemesh Aldo , Kronfeld Joel , Yam Ruth , Flexer Akiva
Published: July 2016

A detailed profile of the stable isotopes of carbon and oxygen was obtained from a speleothem (stalagmite) from the Ceremosjna Cave in eastern Serbia. The stalagmite is a low magnesian calcite that did not show any evidence of diagenetic alteration. It was precipitated under isotopic equilibrium conditions from dripping water. The age and rate of deposition was derived from six internally consistent radiocarbon dates. The initial 14C activity was determined to be approximately 80 pMC. The stalagmite appears to preserve a continuous record of calcite deposition from approximately 2300 BP until the present.

Oxygen isotopic data, based upon 100 samples, are used to derive the first paleotemperature record for Serbia. A regression analysis of the all the data indicates that over the period of time that the speleothem was deposited there was a general trend of lowering of the average temperature. Superimposed upon this are significant long-term temperature fluctuations. These can be divided into four broader climatic groupings. Going from the oldest times to the present, there are two warm periods separated by a period when the temperatures fell below the temperature trend line. However, the absolute temperatures were generally above those of the more recent period that is generally characterized by the coolest climatic conditions.
Can We Use Cosmogenic Isotopes to Date Stone Artifacts?
Authors: Ivy-Ochs Susan , Wüst Raphael , Kubik Peter W , Müller-Beck Hansjürgen , Schlüchter Christian
Published: July 2016

Two chert artifacts from the region near Luxor, Egypt have yielded concentrations of cosmogenic 10Be that allow calculation of nominal exposure ages of 326,000 and 304,000 years. Both artifacts are flakes that were collected atop limestone benches of the Eocene Thebes Formation which form cliffs along the west side of the Nile. The site is at elevation 240 m and is about 15 km from the Nile. Tools associated with these artifacts can be attributed to the Late Acheulean or early Middle Paleolithic (the transition has been suggested to have been on the order of 250,000–300,000 years ago). This area, where abundant chert nodules have weathered out, has been a collection, extraction, and fabrication site since the Early Paleolithic (since at least 400,000 years ago). Surface exposure dating records all periods of exposure. That means these ages represent composite ages, comprised of exposures both before and after working. But what fraction of the 10Be concentration we have measured was acquired before the flakes were produced? Here we propose several approaches to deconvolute the different exposure periods and better approximate the real age of the artifacts. As there is no a priori reason that the two ages should agree with the typological ages of the artifacts, nor for the two independent ages to agree, these first results are especially exciting and intriguing.
Radiocarbon Ages of Beach Rocks and Late Holocene Sea-Level Changes in the Southern Part of the Nansei Islands, Southwest of Japan
Authors: Omoto Kunio
Published: July 2016

Beach rock is a good indicator of the past sea levels, as it is considered to have been formed within the range of intertidal zone. Radiocarbon dates of beach rocks collected from Iriomote Island, Ishigaki Island, and Miyako Island, in the southern part of the Nansei Islands, indicate that the beach rocks were formed between around 4000 BP and 400 BP. Late Holocene sea-level changes were revealed based on the elevations and 14C dates of the beach rocks. The results indicate that the sea level was similar to the present one for at least the past 4000 BP. Isotopic fractionations (δ13C) of the beach rocks were between +9.40% and −0.08%, suggesting a different origin for calcium carbonate.
Coral Reef Evolution at the Leeward Side of Ishigaki Island, Southwest Japan
Authors: Yamano Hiroya , Abe Osamu , Kitagawa Hiroyuki , Niu Etsuko , Nakamura Toshio
Published: July 2016

In comparison with windward coral reefs, the facies and evolution of leeward coral reefs has been discussed to a lesser extent. By accelerator mass spectrometry (AMS) carbon-14 dating of coral specimens collected from the trench excavated across a modern coral reef during a fishery port repair, we revealed the internal facies and Holocene evolution of a leeward reef in Ishigaki Island, Ryukyu Islands, southwest Japan. The reef facies can be split into three facies: the tabular Acropora framework facies, the tabular Acropora reworked facies, and the unconsolidated bioclast facies. The tabular Acropora reworked facies first formed a ridge by 3500 BR Then, the tabular Acropora framework facies grew both upward and seaward. The accumulation rates of the tabular Acropora framework facies ranged from 2.2 to 8.3 m/ka. Thus, the reef framework facies and accumulation rates of this leeward reef is similar to those of windward reefs, although the age of the reef top is younger than that of windward reefs.
Mortar Dating Using AMS 14C and Sequential Dissolution: Examples from Medieval, Non-Hydraulic Lime Mortars from the Åland Islands, SW Finland
Authors: Lindroos Alf , Heinemeier Jan , Ringbom Åsa , Braskén Mats , Sveinbjörnsdóttir Ámy
Published: July 2016

Non-hydraulic mortars contain datable binder carbonate with a direct relation to the time when it was used in a building, but they also contain contaminants that disturb radiocarbon dating attempts. The most relevant contaminants either have a geological provenance and age or they can be related to delayed carbonate formation or devitrification and recrystallization of the mortar. We studied the mortars using cathodoluminescence (CL), mass spectrometry (MS), and accelerator mass spectrometry (AMS) in order to identify, characterize, and date different generations of carbonates. The parameters—dissolution rate, 13C/12C and 18O/16O ratios, and 14C age—were measured or calculated from experiments where the mortars were dissolved in phosphoric acid and each successive CO2 increment was collected, analyzed, and dated. Consequently, mortar dating comprises a CL characterization of the sample and a CO2 evolution pressure curve, a 14C age, and stable isotope profiles from at least 5 successive dissolution increments representing nearly total dissolution. The data is used for modeling the interfering effects of the different carbonates on the binder carbonate age. The models help us to interpret the 14C age profiles and identify CO2 increments that are as uncontaminated as possible. The dating method was implemented on medieval and younger mortars from churches in the Åland Archipelago between Finland and Sweden. The results are used to develop the method for a more general and international use.
Radiocarbon Dates from the Pleistocene Fossil Deposits of Samwel Cave, Shasta County, California, USA
Authors: Feranec Robert S , Hadly Elizabeth A , Blois Jessica L , Barnosky Anthony D , Paytan Adina
Published: July 2016

Dates obtained from the collagen of 5 mammals from the fossil deposits of Samwel Cave, Shasta County, California, USA, show emplacement during the last glacial maximum. These dates support the assignment of the fauna to the late Pleistocene. The Samwel Cave deposits currently do not appear to be stratified.
Disentangling Geomagnetic and Precipitation Signals in an 80-kyr Chinese Loess Record of10Be
Authors: Zhou Weijian , Priller Alfred , Beck J Warren , Zhengkun Wu , Maobai Chen , Zhisheng An , Kutschera Walter , Feng Xian , Huagui Yu , Lin Liu
Published: July 2016

The cosmogenic radionuclide10Be is produced by cosmic-ray spallation in Earth's atmosphere. Its production rate is regulated by the geomagnetic field intensity, so that its accumulation rate in aeolian sediments can, in principle, be used to derive high-resolution records of geomagnetic field changes. However,10Be atmospheric fallout rate also varies locally depending on rainfall rate. The accumulation rate of10Be in sediments is further complicated by overprinting of the geomagnetic and precipitation signals by10Be attached to remobilized dust, which fell from the atmosphere at some time in the past. Here, we demonstrate that these signals can be deconvoluted to derive both geomagnetic field intensity and paleoprecipitation records of Asian Monsoon intensity in an 80,000-yr-long10Be record from Chinese loess. The strong similarity between our derived paleomagnetic intensity record and the SINT 200 (Guyodo and Valet 1996) and NAPIS 75 (Laj et al. 2002) stacked-marine records suggests that this method might be used to produce multimillion-yr-long records of paleomagnetic intensity from loess. This technique also reveals a new method for extracting quantitative paleoprecipitation records from continental interior regions. Our derived precipitation record is broadly similar to the speleothem δ18O-based records of paleo-Asian Monsoon intensity from Dongge (Yuan et al. 2004) and Hulu (Wang et al. 2001) caves, and suggests that the paleo-Asian Monsoon intensity may be responding to a combination of both Northern and Southern Hemisphere insolation forcing.
Artemis, the New 14C AMS at LMC14 in Saclay, France
Authors: Cottereau E , Arnold M , Moreau C , Baqué D , Bavay D , Caffy I , Comby C , Dumoulin J-P , Hain S , Perron M , Salomon J , Setti V
Published: July 2016

The new facility Artemis was installed in 2003 in Saclay, France. This 3MV NEC Pelletron is dedicated to high-precision radiocarbon measurements for French 14C laboratories. We will present information on Artemis along with our sample preparation methods. Results from measurements on some intercalibration samples will be given along with the values of measured blanks. Finally, we report on some problems we have encountered when measuring sputter cathodes with high CH− outputs.