bluuebunny/crossref_metadata_2025 huggingface dataset:
Using the 14C Bomb Pulse to Date Young Speleothems
Authors: Hodge Ed , McDonald Janece , Fischer Matthew , Redwood Dale , Hua Quan , Levchenko Vladimir , Drysdale Russell , Waring Chris , Fink David
Published: July 2016

Three modern speleothems were sampled at high resolution for radiocarbon analysis to identify their bomb-pulse signatures and to construct chronologies. Each speleothem exhibited a different 14C response, presumed to be related to site characteristics such as vegetation, temperature, rainfall, depth below the surface, and water pathway through the aquifer. Peak 14C activity for WM4 is 134.1 pMC, the highest cited thus far in the literature and suggestive of a lower inertia at this site. Dead carbon fractions for each stalagmite were calculated and found to be relatively similar for the 3 speleothems and lower than those derived from Northern Hemisphere speleothems. An inverse modeling technique based on the work of Genty and Massault (1999) was used to estimate soil carbon residence times. For each speleothem, mean soil 14C reservoir ages differed greatly between the 3 sites, ranging from 2–6.5 to 32–46 yr.
Royal Institute for Cultural Heritage Web-Based Radiocarbon Database
Authors: Van Strydonck Mark , De Roock Edwin
Published: July 2016

The radiocarbon dating laboratory at KIK-IRPA in Brussels was founded in the 1960s. From the beginning, dates were reported at more or less regular intervals in the journal Radiocarbon (Schreurs 1968) as did most of the other 14C laboratories.
Reporting 14C Activities and Concentrations
Authors: Mook Willem G , van der Plicht Johannes
Published: July 2016

Three modes of reporting 14C activities are in use, in part analogous to the internationally accepted (IAEA) conventions for stable isotopes: (1) absolute activity, the specific activity of 14C or the activity per gram of carbon; (2) activity ratio, the ratio between the absolute activities of a sample and the standard; and (3) relative activity, the difference between the absolute activities of a sample and standard material, relative to the absolute standard activity. The basic definitions originate from decisions made by the radiocarbon community at its past conferences. Stuiver and Polach (1977) reviewed and sought to specify the definitions and conventions. Several colleagues, however, have experienced inadequacies and pitfalls in the definitions and use of symbols. Furthermore, the latter have to be slightly amended because of the use of modern measuring techniques.

This paper is intended to provide a consistent set of reporting symbols and definitions, illustrated by some practical examples.
Comparing Carbonate and Organic Ams-14C Ages in Lake Abiyata Sediments (Ethiopia): Hydrochemistry and Paleoenvironmental Implications
Authors: Gibert Elisabeth , Travi Yves , Massault Marc , Chernet Tesfaye , Barbecot Florent , Laggoun-Defarge Fatima
Published: July 2016

We studied a 12.6-m-long sequence from Lake Abiyata (Central Ethiopia) to establish a reliable and accurate chronology for use in global paleoclimatic reconstructions. The 26 accelerator mass spectrometry radiocarbon (AMS 14C) ages, performed on carbonates and organic matter, define 2 parallel chronologies, representing the complete Holocene period. However, these chronologies show a significant discrepancy from 500 to 900 BP in depth; ages obtained on carbonates were always older than those on organic matter. The hydrogeological and geochemical behavior of the Lake Abiyata basin has shed light on this discrepancy. We found that the carbonate crystallization is due mainly to the mixing of lake waters with groundwaters from the multi-layered aquifer contained in the 600-m-thick basement of the lake. The 14C activity of total dissolved inorganic carbon (TDIC) measured by AMS from bottom and surface lake waters (111.4 and 111.8 pMC, respectively) confirms that the mixing occurs at the water-sediment interface. This evidence of groundwater participation in the carbonate crystallization calls into question the current paleoclimatic reconstructions based on inorganic carbonates in lakes. Specific attention should thus be given to the respective proportions of each end-member in the mixing for the quantitative estimation of the groundwater input. This will help to validate the paleoenvironmental reconstructions and to highlight an eventual diagenetical evolution of inorganic carbonates during burial, via the study of pore waters.
Birmingham University Radiocarbon Dates VI
Authors: Shotton F. W. , Williams R. E. G.
Published: July 2016

The following list comprises results obtained during 1971 from both the 1 L and 6 L proportional gas counters at pressures of 1 to 3 atm of methane. Age calculations are based on 95% activity of NBS oxalic acid standard and computed from the Libby half-life of 5570 ± 30 yr. Background samples are synthesized from Welsh anthracite. Errors quoted refer only to the standard deviation (1σ) calculated from a statistical analysis of sample, background, and standard count rates. Recently a Micromass 6 mass spectrometer was installed in the Radiocarbon Dating Laboratory which will enable C13measurements on future samples. Pretreatment is continued as described previously (R., 1969, v. 11, p. 263) but in cases where sample size was insufficient for full pretreatment, details are described.
Hawaii Institute of Geophysics Radiocarbon Dates I
Authors: Buddemeier R. W. , Hufen T. H.
Published: July 2016

The radiocarbon dating laboratory of the University of Hawaii was established with joint support of the Hawaii Institute of Geophysics, the Water Resources Research Center, the Department of Chemistry, and the Graduate Division. The laboratory is located in the Hawaii Institute of Geophysics, on the ground floor of a four-story concrete building, and contains two separate radiocarbon counting systems.
Copenhagen Radiocarbon Dates X
Authors: Tauber Henrik
Published: July 2016

The following list comprises a selected number of measurements made on archaeologic samples from 1959 to December 1971. Measurements of geologic samples will be given in a later date list. A survey of the radiocarbon chronology for the Danish Mesolithic and Neolithic, ensuing from these and previously published dates from the laboratory, has recently been compiled (Tauber, 1972).
University of Kiel Radiocarbon Measurements VII
Authors: Erlenkeuser H. , Willkomm H.
Published: July 2016

This list contains data obtained during 1971. Unless otherwise stated, all organic samples or organic fractions are carefully washed with dil. HCl and dil. NaOH to remove all carbonates. Age calculations are based on 95% of NBS oxalic acid standard activity with modern value A.D. 1950. Results are calculated using the Libby half-life and are given in the B.P. scale. Also ages of shells are calculated with the NBS oxalic acid standard. Ages are not corrected for δC13 variations. Errors correspond to Iσ variation of sample net counting rate including statistics of modern standard and background. Sample activities, if given in per cent refer to 0.95 NBS oxalic acid standard activity.
University of Saskatchewan Radiocarbon Dates VI
Authors: Rutherford A. A. , Wittenberg J. , McCallum K. J.
Published: July 2016

This series reports some of the measurements made since publication of the previous list. Equipment and methods remain as described in Saskatchewan II (R., 1960, v. 2, p. 73). The laboratory operates now commercially, administered by the Saskatchewan Research Council under the direction of A. A. Rutherford.
University of Wisconsin Radiocarbon Dates X
Authors: Bender Margaret M. , Bryson Reid A. , Baerreis David A.
Published: July 2016

Radiocarbon dates obtained since December, 1970, are summarized here. Procedures and equipment have been described previously (R., 1966, v. 8, p. 522). Wood, charcoal, and peat samples are pretreated with dilute NaOH and dilute H3PO4 before conversion to the counting gas, methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HCl instead of H3PO4.
Improved Results Using Higher Ratios of Scintillator Solution to Benzene in Liquid Scintillation Spectrometry
Authors: Koba Motoharu
Published: July 2016

Practical effects of the volumetric or weight ratio of scintillator solution to sample benzene in liquid scintillation spectrometry were examined here for radiocarbon dating. It is concluded, using a LKB-Wallac Quantulus™ 1220 and Teflon™-copper 3 mL vials with scintillator of toluene-based PPO and POPOP, that solutions containing the same concentrations of the same ratio, 1.3 or more, of scintillator solution to sample benzene show the same cpm/g and the same channel value of external standard spectrum, irrespective of different gross volumes of solutions. The addition of scintillator solution reduces background in 0.5 mL or so of benzene, and results in an appreciably enlarged figure of merit.
Gif Natural Radiocarbon Measurements VII
Authors: Delibrias G. , Guillier M. T. , Labeyrie J.
Published: July 2016

C14 dates reported below were obtained mainly at the end of 1968 and during 1969 on archaeologic and geologic samples. Techniques of measurement used are unchanged. Since 1968, 4 complete routine sets have been running, each equipped with a 1 L CO2 proportional counter. One is made of stainless steel with a background of 2.70 cpm at pressure 1 atm and the others are of OFHC copper with a background of either 1.10 or 1.30 cpm for a corresponding pressure of, respectively, 1 or 2 atm. For age calculation, 95% activity of NBS oxalic acid is used as the modern standard and the value of 5570 ± 30 years is used for the half-life of C14. Dates are expressed in years b.p. (before a.d. 1950).
Glasgow University Radiocarbon Measurements V
Authors: Ergin M. , Harkness D. D. , Walton A.
Published: July 2016

Operation of counting systems and preparation of results remain as described previously by Baxter et al. (1969), and Ergin et al. (1970).
Institute of Geological Sciences Radiocarbon Dates III
Authors: Welin E. , Engstrand L. , Vaczy S.
Published: July 2016

This date list was compiled by the Institute of Geological Sciences (U.K.) incorporating data supplied under contract by E. Welin, Radioactive Dating Laboratory, Stockholm. Unless otherwise stated, age figures are in C14 years before a.d. 1950. The half-life of C14 is taken as 5568 years and the error, based on counting statistics of sample, background, and modern, is given as one standard deviation. Correction for C13/C12 fractionation has not been made.
University of Lund Radiocarbon Dates V
Authors: Håkansson Sören
Published: July 2016

The C14 measurements reported here were made in this laboratory between October 1970 and September 1971. Equipment, measurement and treatment of samples are the same as reported previously (R., 1968, v. 10, p. 36-37; 1970, v. 12, p. 534).
Smithsonian Institution Radiocarbon Measurements VII
Authors: Stuckenrath Robert , Mielke James E.
Published: July 2016

This list includes those samples dated between December 1968 and July 1971. Samples before SI-617 were completed before the laboratory was dismantled in April 1969 for renovations in the Smithsonian Institution Building. Samples beginning with SI-617 were dated after December 1970, following re-establishment of the laboratory in new quarters.
Birmingham University Radiocarbon Dates VIII
Authors: Shotton F W , Williams R E G , Johnson A S
Published: July 2016

The following list of dates contains all measurements made during 1973, ie, since our last list (R, 1973, v 15, p 451–468). We have installed this year a Nuclear Enterprises NIM system to be used with our 2.5L Oeschger-type proportional counter (Philips), in addition to our 6L and 1L proportional counters which have worked consistently with Beckman Lowbeta electronics. The Philips counter has been calibrated relative to the Beckman electronics and we are now calibrating it relative to the NIM system.
University of Miami Radiocarbon Dates I
Authors: Stipp J J , Eldridge K L , Cohen S J , Webber K
Published: July 2016

The radiocarbon dating facility is part of the UM Geochronology laboratory housed in the Department of Geology, University of Miami, Main Campus. The laboratory was established to carry out and support research in Pleistocene marine geology, particularly in the Caribbean, and to act as a specialized teaching facility of geochronologic research using radiometric age dating techniques.
University of Cambridge Natural Radiocarbon Measurements XIV
Authors: Switsur V R , West R G
Published: July 2016

The dates presented in this paper comprise results of determinations made at the University Radiocarbon Dating Research Laboratory, mostly during the latter half of 1974. Radioactivity was measured with proportional counters using pure carbon dioxide at 2 atmospheres pressure as filling gas. Effects of cosmic and local environmental radiation on the counters were reduced by surrounding them completely with 1) a plastic scintillator anticoincidence shield, 7.5cm thick, viewed by 2 photomultiplier tubes operating in coincidence mode, the output pulses of which were in anticoincidence with the proportional counters signals, and 2) by a 17.5 ton lead castle.
Gif Natural Radiocarbon Measurements X
Authors: Delibrias Georgette , Guillier M-T , Labeyrie Jacques
Published: July 2016

The following date list includes archaeologic and geologic samples dated by Gif Radiocarbon Laboratory mostly from 1973 to 1975. Volcanic samples reported here were dated up to 1981. Measurements were made in the same manner as previously reported (R, 1972, v 14, p 280). For undersized samples, a 0.1L CO2proportional counter was used with 5000-minute standard measurements. Ages listed are conventional14C ages based on the 5568-year Libby half-life; uncertainties are 1σ statistical standard error. Results are based on 95% of NBS oxalic acid activity. Some dates have been calibrated using the correction curve of Kleinet al(1982).
Illinois State Geological Survey Radiocarbon Dates IX
Authors: Liu Chao-Li , Riley Kerry M , Coleman Dennis D
Published: July 2016

The following list contains samples of geologic interest that were processed from June 1980 through March 1983 at the Illinois State Geological Survey (ISGS) Radiocarbon Dating Laboratory. The benzene liquid scintillation technique was used following laboratory procedures previously reported by Coleman (1973, 1974).
High-Precision Calibration of the Radiocarbon Time Scale, 500–2500 bc
Authors: Pearson Gordon W , Stuiver Minze
Published: July 2016

This paper is a twin paper to that of Stuiver and Pearson (1986) which covers the time period ad 1950–500 bc. The combined radiocarbon ages of dendrochronologically dated wood presented in this paper covers the time period 500–2500 bc.
High-Precision 14C Measurement of Irish Oaks to Show the Natural 14C Variations from AD 1840 to 5210 BC
Authors: Pearson G W , Pilcher J R , Baillie M G L , Corbett D M , Qua F
Published: July 2016

High-precision measurement of dendrochronologically dated Irish oak at bi-decade/decade intervals has continued in the Belfast laboratory, extending the 14C data base from ca AD 1840 to 5210 BC. The dendrochronology is now considered absolute (see Belfast dendrochronology this conference) (Brown et al, 1986) and a continuous detailed curve is presented, showing the natural variations in the atmospheric concentration of 14C over >7000 years. Each data point has a precision of <2.5., and some 4500 years have now been compared with Seattle, giving excellent agreement. Discussion of this data base and the justification of the claimed accuracy is given together with a comparison of other chronologies. Some of the advantages and limitations of the above are discussed.
High-Precision Calibration of the Radiocarbon Time Scale, 3930–3230 Cal BC
Authors: de Jong AFM , Becker Bernd , Mook WG
Published: July 2016

This paper contains 14C results obtained by the special high-precision proportional gas counter, designed by Tans and Mook (1978), on tree rings from the South German oak chronologies: Donau 7, 3, 10, and 12, originating from the Danube River basin (48° 24’ N, 10° 5’ E).
The Reliability of Radiocarbon Dating Buried Soils
Authors: Orlova L. A. , Panychev V. A.
Published: July 2016

Variable 14C ages of paleosol organic matter (OM) cause difficulties in interpreting 14C data. We attempt to determine the reliability of OM 14C dates by examining different carbon-containing materials from soil horizons and paleosol fractions.
Problems and Methods of Dating Low-Activity Samples by Liquid Scintillation Counting
Authors: Arslanov Kh. A. , Tertychnaya T. V. , Chernov S. B.
Published: July 2016

The important problem of contamination of old samples by younger 14C necessitates treatment of organic and carbonate samples to ensure more complete removal of contaminating carbon. Here we present studies of chemical procedures for the liquid scintillation method of 14C dating undertaken since 1960 in the former USSR. We discuss new procedures such as lithium carbide synthesis from charred organic samples and benzene synthesis on a V2O5·Al2O3·SiO2 catalyst, as well as memory effect in the carbide synthesis procedure and characteristics of two homemade counters.
Radiocarbon Chronology of Paleogeographic Events of the Late Pleistocene and Holocene in Russia
Authors: Kaplin P. A. , Svitoch A. A. , Parunin O. B.
Published: July 2016

14C chronology of Late Pleistocene paleogeographical events in the Black Sea–Caspian Sea region shows that the following transgressions partly correlate with each other: Karangat and Khazarian; Neo-Euxinian and Khvalyn; Holocene and Neo-Caspian. The main climatic events were synchronous in intercontinental Siberia. In the far eastern region, the Middle-Wisconsinan transgression is reflected by Chukotka and western Kamchatka terraces and by submerged ancient shorelines in Primorye.
Geochronology of the Holocene of the Belorussian Polessie
Authors: Matveev A. V. , Krutous E. A. , Zernitskaya V. P.
Published: July 2016

We distinguished major stages of the last glaciation (Bølling, Older Dryas, Allerød, Younger Dryas) and the Holocene by radiocarbon dating and paleobotanical analyses. Our paleobotanical investigation of peatlands is well correlated with independent14C data. We establish that the Atlantic and Subboreal stages of the Holocene have three divisions, and that the Subatlantic has two.
Radiocarbon Dating Organic Detritus: Implications for Studying Ice Sheet Dynamics
Authors: Punning Jaan-Mati , Rajamäe Raivo
Published: July 2016

We present here a description of the 14C dating method used at the Institute of Geology, Estonian Academy of Science. We discuss results of geochronological studies of several stratigraphic sections, from which we estimate the age of the Late Weichselian (Late Valdaian) glacial maximum. 14C and paleobotanical data indicate that biodetrital materials comprise organic debris from various sources and suggest only a maximum age of investigated strata (16,000 BP).
Radiocarbon Dating and Tephrochronology in Kamchatka
Authors: Braitseva O. A. , Sulerzhitsky L. D. , Litasova S. N. , Melekestsev I. V. , Ponomareva V. V.
Published: July 2016

We discuss results of 14C dates obtained from areas of young volcanoes in Kamchatka. We apply these dates to reconstructing regional volcanic activity during the Holocene.
Radiocarbon Chronology of Archaeological Sites of the Kurile Islands
Authors: Zaitseva G. I. , Popov S. G. , Krylov A. P. , Knorozov Yu. V. , Spevakovskiy A. B.
Published: July 2016

One of the theories of Paleo-Indian migration from Asia to America (Chard 1963) proposes that the most probable route was along the coast of the Sea of Okhotsk through Japan, Kamchatka and the Aleutian islands. To study the problem of New World population origins, we are attempting to correlate archaeological sites in this region. Our aim is to examine connections of the earliest cultures of the Far East and Siberia with the cultures of Sakhalin, the Kurile Islands, Japan and America.
A Simple Technique for Converting CO2 to AMS Target Graphite
Authors: Wilson A. T.
Published: July 2016

I describe a simple, rapid and inexpensive method for converting CO2 samples into AMS target graphite. The technique is applicable for both small- and large-scale production facilities. With some modification, the method is suitable for use with very small samples.
Illumination of a Black Box: Analysis of Gas Composition During Graphite Target Preparation
Authors: McNichol A. P. , Gagnon A. R. , Jones G. A. , Osborne E. A.
Published: July 2016

We conducted a study of relative gas composition changes of CO2, CO and CH4during the formation of graphite targets using different temperatures, catalysts and methods. Reduction with H2increases the reaction rate without compromising the quality of the AMS target produced. Methane is produced at virtually any temperature, and the amount produced is greater at very low temperatures. The reduction of CO to graphite is very slow when H2is not included in the reaction.
Assessment of 0.3-ml Minivials for Radiocarbon Dating by Liquid Scintillation Counting of Benzene
Authors: Hogg A. G.
Published: July 2016

I have made an evaluation of 0.3-ml minivials for 14C dating of small samples by liquid scintillation counting of benzene. A calibrated wood standard was diluted by varying amounts of ancient CO2, with synthesized benzene counted in both conventional 3.0-ml vials and 0.3-ml minivials in a 1220 Quantulus. The accuracy and precision of results are compared for samples ranging in weight from 50 to 240 mg of carbon. I examined two significant potential problems associated with handling small samples, namely, memory effects within the vacuum system, and signal within the dilution gas. Although accurate radiocarbon dates can be obtained using either standard vials or minivials, minivials are more suitable for dating small samples because they are less influenced by these sources of error.
AMS Radiocarbon Dating of Ice: Validity of the Technique and the Problem of Cosmogenic In-Situ Production in Polar Ice Cores
Authors: Wilson A. T. , Donahue D. J.
Published: July 2016

In the “sublimation technique,” carbon dioxide entrapped in ice is recovered by sublimation, converted to graphite and ratio of 14C/13C in the CO2 determined by AMS measurements. We describe here several experiments performed to check the validity of such measurements and to study the effect of cosmogenically produced in-situ14C on the measurements.
Accelerator Mass Spectrometry of 14C at the Australian National University
Authors: Fifield L. K. , Allan G. L. , Ophel T. R. , Head M. J.
Published: July 2016

A 14C measurement capability has been developed on the 14UD accelerator at the Australian National University. At present, this system operates on a medium-precision, low-throughput basis with slow cycling between isotopes. We describe unusual features of the system, and review preliminary experience with this mode of operation, in sample preparation, and with a recently installed injection system.
The IAEA 14C Intercomparison Exercise 1990
Authors: Rozanski Kazimierz , Stichler Willibald , Gonfiantini Roberto , Scott E. M. , Beukens R. P. , Kromer Bernd , Van Der Plicht Johannes
Published: July 2016

As a follow-up to the meeting of experts convened at the International Atomic Energy Agency (IAEA) in February 1989, and the International 14C Workshop held in Glasgow in September 1989, the 14C Quality Assurance Program was formulated. In a joint effort of several radiocarbon teams and IAEA staff, we have prepared a set of five new intercomparison materials. These are natural materials frequently used by radiocarbon laboratories. The materials were distributed to 137 laboratories in May 1990. In February 1991, a meeting of experts was convened in Vienna to evaluate the results, to determine the radiocarbon activity of the five samples expressed in % Modern (pMC) terms and to define the 13C/12C ratio, and to make recommendations on further use of these materials. We present here the results of the exercise and the agreed consensus values for each of the five materials and discuss the different analyses that were undertaken.
Radiocarbon Dating of Anodonta in the Mojave River Basin
Authors: Berger Rainer , Meek Norman
Published: July 2016

A 450-year correction is required to make Anodonta14C dates comparable to 14C dates on other materials in the Mojave River basin. The internal stratigraphic consistency of 34 conventional 14C dates on Anodonta in this drainage basin indicates that such dates are usually reliable. The validity of most conventional 14C dates in the Mojave River basin may be a product of the basin's crystalline bedrock in a region usually typified by thick Paleozoic carbonate sections.
Anthropogenic Influence on the 14C Activity and Other Constituents of Recent Lake Sediments: A Case Study1
Authors: Srdoč Dušan , Horvatinčić Nada , Ahel Marijan , Giger Walter , Schaffner Christian , Bronić Ines Krajcar , Petricioli Donat , Pezdič Jože , Marčenko Elena , Plenković-Moraj Anđelka
Published: July 2016

Anthropogenic activities that introduce an excess of nutrients and other pollutants into rivers and lakes are causing significant changes in their aquatic environment. Excessive nutrients greatly accelerate eutrophication, and lake marl formed during eutrophication differs from that formed in oligotrophic water.

We analyzed recent sediment cores from Prošće and Kozjak lakes located in Plitvice National Park, central Croatia. Analyses consisted of 14C activity of calcareous lake marl, the ratio of stable isotopes (δ13C, δ18O), organic compounds in the sediment and the distribution of diatoms. Previous 14C activity measurements helped to determine the sedimentation rate and thus the time period of increased input of nutrients into lakes. We determined the increased 14C activity in lake sediments caused by nuclear bomb effect in recent depth profiles. We attributed the sudden increase in diatom species, Cyclotella operculata unipuctata and Achnanthes clevei rostrata, in the uppermost 5-cm layer, to eutrophication of the lake water.

We performed a molecular characterization of hydrocarbons isolated from the sediments, and applied computer-assisted high-resolution gas chromatography/mass spectrometry to estimate contributions of biogenic, fossil and pyrolytic hydrocarbons.
A Comparison of Radiocarbon and U/Th Ages on Continental Carbonates
Authors: Fontes J.-C. , Andrews J. N. , Causse Christiane , Gibert Elisabeth
Published: July 2016

Authigenic micrite from a playa in the northern Sahara has been dated by both the U/Th and 14C methods. The U/Th ages can be a few thousand years greater or less than the 14C ages obtained on the smallest crystals of micrite. The latter are considered to form a reasonable chronology for the Holocene deposits. The deviations of the U/Th ages are explained by quantifiable losses and gains of uranium under changing redox conditions. Under conditions where U is conservative (reduced sediments with low permeability), the U/Th method can provide good chronologies for lacustrine deposits.
Reaction-Path Formulation of a Simple Dissolution Model for Radiocarbon Dating Groundwater
Authors: Cheng Songlin
Published: July 2016

Since the pioneer publication of K. O. Münnich (1957), 14C systematics have been used in many hydrogeological studies. Because of the complexity of carbon geochemistry, numerous models have been proposed to correct the dilution effect of “dead” carbon in groundwater. All the 14C correction models for dating groundwater are based on either open- or closed-system conditions. I present here a simple model that accounts for the effects of both open- and closed-system dissolution of carbonate and aluminosilicate minerals. For systems involving precipitation of carbonate minerals and redox reactions of organic matter, reaction-path simulations are essential for reliable 14C dating of groundwater.
14C Activity in Different Sections and Chemical Fractions of Oak Tree Rings, AD 1938–1981
Authors: Olsson Ingrid U. , Possnert Göran
Published: July 2016

The14C activity in rings from an oak tree grown in a suburb of Uppsala, Sweden has been studied for the period, AD 1938 to 1981. We compare the results with the atmospheric carbon dioxide records from Abisko, northern Sweden, where local or regional contamination from fossil-fuel combustion can be disregarded. We assess the influence from different chemical pretreatment procedures in use and compare HCl-NaOH-HCl treatment with cellulose extraction. We split each ring into two samples corresponding to early (spring) and late wood. A more refined partitioning has been applied to the years 1963 and 1964.
A New Tree-Ring Width, δ13C and 14C Investigation of the Two Creeks Site
Authors: Leavitt Steven W. , Kalin Robert M.
Published: July 2016

We have made isotopic and dendrochronologic measurements on material collected from the Two Creeks site. Radiocarbon dating of outside wood of four logs yielded an average age of 11,760 ± 100 BP, in good agreement with results of Broecker and Farrand (1963) over 25 years ago. The range of 11,640 ± 160 to 11,900 ± 160 BP suggests a period of forest growth of 200–300 years, consistent with a ring-width chronology established by Kaiser (1987). Ring counting of five specimens gave a range of individual tree ages from 110 to 182 years, and width measurements indicate very low year-to-year variation in ring size. However, preliminary cross-dating of five samples produced a 202-year floating chronology. Stable-carbon isotope chronologies on cellulose from five-year ring groups show δ13C scatter among trees typical of that found within modern sites, with some matches of isotopic maxima and minima. Some downward δ13C trends may result from physiological response to rising lake levels (and/or cooling temperatures) at the site, which also produced very narrow rings in the outer ca. 50 ± 20 years.
Radiocarbon Variations from Tasmanian Conifers: First Results from Late Pleistocene and Holocene Logs
Authors: Barbetti Mike , Bird Trevor , Dolezal George , Taylor Gillian , Francey Roger , Cook Edward , Peterson Mike
Published: July 2016

Dendrochronological studies have begun on two conifer species in the Stanley River area of western Tasmania. The chronology extends to 273 BC for Huon pine (Lagarostrobos franklinii) and to AD 1450 for celery-top pine (Phyllocladus aspleniifolius). Apart from living or recently felled trees, sections have been taken from 58 logs preserved in floodplain sediments. Two of these logs have late Pleistocene ages, centered around 13.0 and 12.7 k 14C yr bp. Four logs are between 8 and 9 ka BP, and one is centered at 7.3 ka bp. The remaining logs have various ages between 6.2 ka BP and the present. 14C measurements have been performed on decadal samples from the two late Pleistocene logs, providing short (260-yr) records of atmospheric 14C variations when plotted against individual ring numbers. Decadal measurements on the 7300-yr-old log have been wiggle-matched with 14C calibration curves from German oak and bristlecone pine. Measurements for the period, AD 1600–1800, show good agreement with northern hemisphere results, and a nearly zero offset between the hemispheres.
Chronology of the Baxie Loess Profile and the History of Monsoon Climates in China Between 17,000 and 6000 Years BP
Authors: Zhou Weijian , An Zhisheng , Lin Benhai , Xiao Jule , Zhang Jinzhao , Xie Jun , Zhou Mingfu , Porter S. C. , Head M. J. , Donahue D. J.
Published: July 2016

The valley of the Baxie River, situated in the western region of the Loess Plateau in central China, contains a loess profile 15 m thick, which can be considered representative of loess-paleosol sequences formed over the last 17 ka. Both thermoluminescence (TL) determinations on fine-grained sediment (4–11 μm) and 14C determinations on various organic fractions of paleosols from the profile have provided an extremely useful chronological framework for these sequences. These sequences indicate a weakened summer monsoon during the last glacial maximum followed by a strengthening of the summer monsoon, beginning ca. 13 ka cal bp. An abrupt change to a weakened summer monsoon regime lasted from ca. 10.9 to 10.2 ka cal bp. The Asian summer monsoon circulation, recording the Holocene optimum, then increased and lasted from ca. 10.2 to 6 ka cal bp. The organic component of samples taken down the profile has δ13C values ranging from −21 to −24‰ with respect to the PDB standard. The more positive δ13C values suggest that the proportion of C4-type plants in river valleys of the Loess Plateau increased as Asian summer monsoon influence weakened, and C3-type vegetation increased as the summer monsoon influence strengthened. Magnetic susceptibility and organic content were low during loess deposition, also reflecting weakening of summer monsoon. Two 14C determinations on the humin fraction of the organic component near the top of the lower paleosol and the base of the upper paleosol complex gave ages of 10.2 and 10.9 ka cal BP, respectively. These ages mark the beginning and termination of a brief event involving increased dust influx under weakened summer monsoon conditions.
Results and Methods in the Radiocarbon Dating of Pottery
Authors: Hedges R. E. M. , Tiemei Chen , Housley R. A.
Published: July 2016

The main problem with dating pottery by radiocarbon is that many different carbon sources, of different radiocarbon age, may contribute to the potsherd carbon content. Also, the process of firing is liable to destroy information that might help separate possible sources. We describe several pottery dating projects in which we have dated separate fractions (such as humics, lipids and classes of residual carbon). Although in some cases consistency between results is sufficient to accept that this approach can give a credible date, in other cases, no date has been possible, and general conclusions are difficult to make.
Geological Survey of Canada Radiocarbon Dates VIII
Authors: Lowdon J. A. , Wilmeth R. , Blake W.
Published: July 2016

The Radiocarbon Dating Laboratory of the Geological Survey of Canada routinely operates two proportional counters; one 2 L and one 5 L. The 2 L counter is operated entirely at 2 atm. and the 5 L counter mainly at 1 atm. On occasion the 5 L counter is operated at 4 atm. Detailed descriptions of these two counters have recently been published (Dyck, 1967a). A I L counter has been fabricated and is now undergoing preliminary testing.
Smithsonian Institution Radiocarbon Measurements V
Authors: Mielke James E. , Long Austin
Published: July 2016

Included in this list are analyses made during 1967 and the first half of 1968 with equipment and techniques previously employed here. All methane was produced in the bomb reactor.
Late Quaternary Chronology and Stratigraphy of Twelve Sites On Kaua‘i
Authors: Burney David A
Published: July 2016

Twelve new sites on Kaua‘i provide an island-wide view of late Quaternary (near time) environments on the oldest of the major Hawaiian Islands. Radiocarbon-dated lithologies are compared for estuarine sites on windward and leeward coasts, interior peat bogs ranging from 169 to 1220 m in elevation, prehistoric fishponds, and a sinkhole paleolake in the Maha‘ulepu cave system. Terrestrial sedimentation begins in many coastal sites about 6000 cal BP, as sea level approached modern levels. Prehuman sedimentation rates were quite low in all these sites, generally <2 mm/yr, although coastal sites in the late Holocene were subject to major episodic sediment influx from extreme events, including tsunamis, hurricanes, and floods. Interior sites are generally older, having accumulated humic clay and peat layers at least since the late Pleistocene. Since the arrival of humans less than two millennia ago, sedimentation rates have increased in some coastal sites, and further local increases (as much as two orders of magnitude) have occurred since European arrival. Evidence from sites containing fossils of extinct terrestrial snails is consistent with the hypothesis that human-caused extinctions have proceeded in three phases, corresponding to losses (generally the largest species) occurring soon after the arrival of the first humans, followed by a second wave of extinction in late prehistoric times, and a third after European colonization. Dating of sediments from fishponds constructed or enhanced by prehistoric Polynesians suggests that this early form of aquaculture was initiated on Kaua‘i by about 830 ± 50 BP. The most elaborate example of fishpond construction in the Hawaiian Islands, the Alekoko or Menehune fishpond on Kaua‘i's southeast coast, was probably undertaken by 580 ± 30 BP.
Radiocarbon and Stable Isotope Analyses of Archaeological Bone Consolidated with Hide Glue
Authors: Takahashi C M , Nelson D E , Southon J S
Published: July 2016

We tested a simple method for removing a collagen-based glue preservative from bone destined for radiocarbon and stable isotope analyses. The method is sufficient for bone samples from which only stable isotope measurements are required. For 14C dating, such samples of age less than about 10 ka can be adequately dated, but for older samples, the circumstances must be carefully evaluated.
Novel Statistical Model for a Piece-Wise Linear Radiocarbon Calibration Curve
Authors: Aguilar Delil Gómez Portugal , Litton Cliff D , O'Hagan Anthony
Published: July 2016

The process of calibrating radiocarbon determinations onto the calendar scale requires the setting of a specific statistical model for the calibration curve. This model specification will bear fundamental importance for the resulting inference regarding the parameter of interest—namely, in general, the calendar age associated to the sample that has been 14C-dated.

Traditionally, the 14C calibration curve has been modelled simply as the piece-wise linear curve joining the (internationally agreed) high-precision calibration data points; or, less frequently, by proposing spline functions in order to obtain a smoother curve.

We present a model for the 14C calibration curve which, based on specific characteristics of the dating method, yields a piece-wise linear curve, but one which rather than interpolating the data points, smooths them. We show that with this specific model if a piece-wise linear curve is desired, an underlying random walk model is implied as covariance structure (and vice versa). Furthermore, by making use of all the information provided by the calibration data in a comprehensive way, we achieve an improvement over current models by getting more realistic variance values for the calibration curve.
Are the 14C Dates of the Dead Sea Scrolls Affected by Castor Oil Contamination?
Authors: Carmi Israel
Published: July 2016

The paper “The effects of possible contamination on the radiocarbon dates of the Dead Sea Scrolls I: castor oil” by Rasmussen et al. (2001) is discussed. Detailed analysis of the extant dates of the Dead Sea Scrolls suggests that the pretreatment of the samples was adequate. Errors and omissions in the paper are discussed and the implications of the experiment of Rasmussen et al. (2001) are questioned.
AMS Dating of Human Bone from Palau: New Evidence for a Pre-2000 BP Settlement
Authors: Fitzpatrick Scott M
Published: July 2016

Direct dating of a human bone fragment from the Chelechol ra Orrak site (western Micronesia) has yielded one of the earliest dates for Palau thus far. This date compares well with recently collected paleoenvironmental evidence and radiocarbon dates on Babeldaob Island suggesting that settlement of the Palauan archipelago took place much earlier than previously thought.
Woce Radiocarbon IV: Pacific Ocean Results; P10, P13N, P14C, P18, P19 & S4P
Authors: Key Robert M , Quay Paul D , Schlosser Peter , McNichol A P , von Reden KF , Schneider Robert J , Elder Kathy L , Stuiver Minze , Göte Östlund H
Published: July 2016

The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic survey of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. investigators for both conventional large volume p counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale surveys. The 14C distribution for the entire WOCE Pacific data set is graphically described using mean vertical profiles and sections, and property-property plots.
14C Dating of Laser-Oxidized Organics
Authors: Watchman A. L. , Lessard R. A. , Jull A. J. T. , Toolin L. J. , Blake Weston
Published: July 2016

We used a continuous krypton ion laser to rapidly oxidize milligram-sized fragments of coniferous driftwood of known ages, and dated the resulting carbon dioxide by accelerator mass spectrometry (AMS). AMS14C ages of non-pretreated young wood from different parts of two logs were within 10% of the ages of conventionally determined alkaline insoluble fractions. The age of the oldest whole wood measured after laser oxidation was within the error ranges of conventional values.
Climate in the Great Lakes Region Between 14,000 and 4000 Years Ago from Isotopic Composition of Conifer Wood
Authors: Leavitt Steven W , Panyushkina Irina P , Lange Todd , Wiedenhoeft Alex , Cheng Li , Hunter R Douglas , Hughes John , Pranschke Frank , Schneider Allan F , Moran Joseph , Stieglitz Ron
Published: July 2016

The isotopic composition of ancient wood has the potential to provide information about past environments. We analyzed the δ13C, δ18O, and δ2H of cellulose of conifer trees from several cross-sections at each of 9 sites around the Great Lakes region ranging from ∼4000 to 14,000 cal BP. Isotopic values of Picea, Pinus, and Thuja species seem interchangeable for δ18O and δ2H comparisons, but Thuja appears distinctly different from the other 2 in its δ13C composition. Isotopic results suggest that the 2 sites of near-Younger Dryas age experienced the coldest conditions, although the Gribben Basin site near the Laurentide ice sheet was relatively dry, whereas the Liverpool site 500 km south was moister. The spatial isotopic variability of 3 of the 4 sites of Two Creeks age shows evidence of an elevation effect, perhaps related to sites farther inland from the Lake Michigan shoreline experiencing warmer daytime growing season temperatures. Thus, despite floristic similarity across sites (wood samples at 7 of the sites being Picea), the isotopes appear to reflect environmental differences that might not be readily evident from a purely floristic interpretation of macrofossil or pollen identification.
Radiocarbon Chronology of Prehistoric Campsites in Alpine and Subalpine Zones at Haleakalā, Maui Island, USA
Authors: Carson Mike T , Mintmier Melanie A
Published: July 2016

A chronological synthesis of prehistoric campsites in alpine and subalpine zones (∼2–3 km asl) at Haleakalā, Maui Island, USA, is based on relative stratigraphy from 24 test excavations, associated artifacts of known or probable time periods, and 12 radiocarbon dates. The results indicate intensive use of the unfavorable high-altitude environment in the range of AD 1400–1600, with very limited use slightly earlier. Numerous campsites were used repeatedly near the Haleakalā crater rim and scattered on the lower western mountain slope. Prior to this time, activity in this inhospitable setting was infrequent and occurred on a small scale.
The 3MV Multi-Element AMS in Xi'an, China: Unique Features and Preliminary Tests
Authors: Zhou Weijian , Zhao Xiaolei , Xuefeng Lu , Lin Liu , Zhengkun Wu , Peng Cheng , Wengnian Zhao , Chunhai Huang
Published: July 2016

A 3MV multi-element accelerator mass spectrometer (AMS) has been installed in Xi'an, China, and preliminary tests have been completed. The results of both background and precision tests for 4 nuclides are 3.1 × 10–16, 0.2% (14C); 1.8 × 10–14, 1.4% (10Be); 2.3 × 10–15, 1.14% (26Al); and 2.0 × 10–14, 1.75% (129I). The unique features of this facility are the newly developed ion source accepting solid and CO2 samples; the specially designed low-energy injector, including a “beam blanking unit” and “Q-snout”; the acceleration tube structure with the combined magnetic and electrostatic suppression; and the function of the slit stabilization in the post-acceleration system. These features are discussed in terms of the end-user's point of view.
Passion Framed by Art: Helen Faucit's Juliet
Authors: Carlisle Carol J.
Published: July 2016

A Victorian actress who undertook the part of Shakespeare's Juliet was faced with a paradoxical situation typical of her age: the role offered her a chance to create two effects that had tremendous appeal to her audience — ecstatic love and gothic horror — yet she could not take full advantage of her opportunities without risking some critical condemnation. Among the actresses who successfully exploited the possibilities without being caught in the pitfalls was Helen Faucit, who chose Juliet for her “first appearance on any stage” in 1833 and continued to act it until her last professional engagement in 1871. Because Miss Faucit was particularly skillful in resolving the problems I have mentioned, her Juliet offers an interesting study in technique. I propose, first, to discuss the problems themselves, then to describe two closely-related methods by which Helen Faucit dealt with them, and, finally, to illustrate her use of these methods in several major scenes.
Accounting for the Audience in Historical Reconstruction: Martin Jones's Production of Langston Hughes'sMulatto
Authors: Plum Jay
Published: July 2016

Although Langston Hughes'sMulattoholds the record as the second longest Broadway production of a play by an African American playwright (surpassed only by Lorraine Hansberry'sA Raisin in the Sun), the reasons behind its commercial success have been virtually ignored. This oversight in part reflects a tendency among theatre scholars to treat the dramatic text as the primary (if not the only) source of a play's meaning. In the case ofMulatto, academic critics have debated its literary merit according to questions of form and genre. Webster Smalley, in his introduction to the collected plays of Langston Hughes, for instance, defendsMulattoas a tragedy, arguing that the play avoids the tendency of social dramas of the 1930s “to oversimplify moral issues as in melodrama” because of the recognition of Bert's “tragic situation” (he must kill himself or be killed by an angry lynch mob). For those critics who insist thatMulattois melodramatic, Smalley advises, “let [them] look to the racial situation in the deep South as it is even today [i.e., 1963]: it is melodramatic.” Smalley presupposes a dichotomous relationship between fiction and reality, advancing a mimetic theory in which representation directly corresponds to the real. Rather than answering specific charges, he defines contemporary race relations as melodrama, implying thatMulatto, even if melodramatic, is “natural” and “accurate.”
What Are the Rules of the Game? Some Remarks on The Yellow Jacket
Authors: Lichte Erika Fischer
Published: July 2016

The vast caravan out of Ceylon … arrived safely in Europe in April 1884 … There were sixty-seven people, twenty-five elephants … and a great many oxen of various kinds. The ethnographic exhibition included hundreds of different shows, and even the vegetative world was represented in numerous exhibits … My Singhalese troupe was veiled in the ancient wondrous world of India; not only had we captured the vibrant, picturesque, outward appearance of India, but also the shimmer of its mystique. The colourful, captivating sight of the caravanserai, the majestic elephants, partly bedecked in golden saddlery, partly in work harnesses, pulling gigantic loads; the slim, attractive, doe-eyed dancers with their sensuous movements and last of all the great religious Perra-Harra procession-conjured up a magic web which subjected the public entirely to it … The exhibition was opened in Hamburg… After Hamburg came Düsseldorf, Frankfurt, and Vienna … From Vienna it went to Berlin … In the following years, 1885 and 1886, I traveled with the same exhibition through southern Germany, Switzerland and Vienna a second time, and finally set out for England … It was in Paris, at the height of its success, that the Ceylon exhibition finally came to an end. The average number of visitors to the Jardin d'Acclimatisation on a Sunday was 50,000-60,000. Throughout the two and a half month duration of the exhibition, the number of visitors was nearly one million.