bluuebunny/crossref_metadata_2025 huggingface dataset:
University of Bonn Natural Radiocarbon Measurements VII
Authors: Scharpenseel H W , Pietig F
Published: July 2016

Radiocarbon measurements, mainly on soil and water samples are being continued. Benzene samples are prepared as described earlier (Scharpenseel and Pietig, 1969; 1970). Radioactivity is measured in a single quartz vial, and also with 13 specially manufactured, low background Teflon/Duraluminium vials, similar to the system described by Polach (1971, pers commun).
Radioisotopes Laboratory Radiocarbon Date List I
Authors: Sumodi A J
Published: July 2016

The Radioisotopes Laboratory was established in January 1972, in order to supply radiocarbon measurements of various samples to several institutions. Active analyses commenced in June following the testing and evaluation of equipment and known samples for accuracy and reproducibility. During this time, data was accumulated for the statistical establishment of counting accuracy, particularly for background activity.
University of Pennsylvania Radiocarbon Dates XVI
Authors: Michael H N , Ralph E K
Published: July 2016

On two previous occasions we have published lists of 14C results of precisely dated wood samples in Radiocarbon as per mil deviations (R, 1965, v 7, p 179–186; R, 1969, v 11, no. 2, p 469–481). We have also published a list of 14C dates, consolidating all dated wood samples processed in our lab to July 1969 (Ralph and Michael, 1970).
Vienna Radium Institute Radiocarbon Dates V
Authors: Felber Heinz
Published: July 2016

Measurements have continued with the same proportional counter system, pretreatment procedure, methane preparation and measurement, and calculation using a half-life of 5568 ± 30 years, as described previously (R, 1970, v 12, p 298–318). Uncertainties quoted are single standard deviations originating from standard, sample, background counting rates and half-life. No 13C/12C ratios were measured.
Institut Royal Du Patrimoine Artistique Radiocarbon Dates V
Authors: Dauchot-Dehon M , Heylen J
Published: July 2016

This list includes the results of measurements made during 1972–73.
University of Georgia Radiocarbon Dates IV
Authors: Brandau Betty Lee , Noakes John E
Published: July 2016

The following list of dates is compiled from samples prepared since publication of our last date list (R, 1974, v 16, p 131–141). The counting equipment and operating procedures are the same. Ages are quoted with a 1σ counting error which includes statistical variation of the sample count as well as for background and standard, using ad 1950 as the reference year and 95% NBS oxalic acid for 14C dating as the standard. The half-life value used is 5570 years.
Rudjer Bošković Institute Radiocarbon Measurements III
Authors: Srdoč Dušan , Sliepčevic Adela , Planinic Josip
Published: July 2016

The following list contains dates of samples measured since our previous list (R, 1973, v 15, p 435–441). As before, age calculations are based on the Libby half-life 5568 ± 30 yr, and reported in years before 1950. The modern standard is 0.950 of the activity of NBS oxalic acid.
University of Miami Radiocarbon Dates V
Authors: Eldridge K L , Stipp J J , Hattner J
Published: July 2016

The following list of dates are selected from geologic and archaeologic samples measured in early 1975. The technique employed is liquid scintillation counting of wholly synthesized benzene as described by Noakes et al (1965) and discussed in R, v 16, p 402–408. Errors are reported as one standard deviation.
University of Wisconsin Radiocarbon Dates XIII
Authors: Bender Margaret M , Bryson Reid A , Baerreis David A
Published: July 2016

Procedures and equipment of the laboratory have been described in previous date lists. Lake cores and marls are treated with acid only, wood, charcoal, and peat samples with dilute NaOH and dilute H3PO4(unless indicated otherwise) before conversion to methane which is used as counting gas.
Marine Resources Research Institute Radiocarbon Dates I
Authors: Mathews Thomas D
Published: July 2016

In January 1975 a radiocarbon dating laboratory was established at the Marine Resources Research Institute for geochemical and geologic studies. A liquid scintillation system is employed according to the method of Noakes, Kim, and Akers (1967). A Searle (Nuclear Chicago) Isocap 300 liquid scintillation counter is currently being used for counting. This system is a duplicate of the one formerly used at Texas A & M University except for the counter (Mathews et al, 1972)
Brooklyn College Radiocarbon Dates I
Authors: Williams Evan T
Published: July 2016

This radiocarbon laboratory was established by a grant from Brooklyn College to support the work of its archaeologists and geologists. The method of dating is that of benzene synthesis and liquid-scintillation counting developed by a number of investigators (Noakes et al, 1965; Polach and Stipp, 1967; Tamers, 1975). This list includes nearly all samples processed so far, most of which were done since September 1975.
University of Pennsylvania Radiocarbon Dates XIX
Authors: Fishman Bernard , Forbes Hamish , Lawn Barbara
Published: July 2016

This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R, 1975, v 17, p 196-215) as well as many samples dated previously which lacked adequate sample information.
Geological Survey of Finland Radiocarbon Measurements VII
Authors: Heikkinen Aulis , Äikää Osmo
Published: July 2016

This list of measurements includes most of the geologic samples dated in this laboratory since the publication of our last list (R, 1974, v 16, p 252-268).
University of Texas At Austin Radiocarbon Dates XI
Authors: Valastro S , Davis E Mott , Varela Alejandra G
Published: July 2016

This list reports14C measurements completed between August 1973 and November 1975. Other projects completed in that period will be reported later. Age calculations are based on14C half-life of 5568 yr and modern standard of 95% NBS oxalic acid, supplemented by tree rings of pre-industrial wood from a log cut in the 1850's (Tx-540; R, 1970, v 12, p 249). Deviations reported are based on counting statistics of sample, background, and modern, and are ± 1σ, except that when sample count approaches either modern or background, 2σ limits are reported. Unless noted,12C/13C measurements were not made and results are not corrected for13C fractionation. The laboratory uses liquid scintillation counting of benzene, with Li2C2and vanadium-activated catalyst in preparation; chemical yields range between 95% and 99%. Three counters are employed: a Packard Tri-Carb Model 3002, and 2 Beckman LS-230 spectrometers obtained through a grant from the National Science Foundation.
University of Miami Radiocarbon Dates IX
Authors: Piepgras D , Stipp J J
Published: July 2016

The following radiocarbon measurements are a partial list of geologic samples dated since September 1975. The technique used is described in R, v 18, p 210-220. Dates are calculated using a 14C half-life of 5568 yr and errors are reported as one standard deviation. This includes only the counting errors on the sample, background and modern standard.
University of Lund Radiocarbon Dates X
Authors: Håkansson Sören
Published: July 2016

Most of the14C measurements reported here were made between October 1975 and October 1976. Equipment, measurement, and treatment of samples are the same as reported previously (R, 1968, v 10, p 36-37; 1976, v 18, p 290).
University of Miami Radiocarbon Dates X
Authors: Piepgras D , Allison M A , Dlugos T , Stipp J J
Published: July 2016

The following dates are a partial list of archaeologic and geologic samples measured since spring of 1976. The method used is described by (Stipp et al, 1976). Errors reported are one standard deviation and include only the counting errors on the unknown sample, background, and modern standard. No corrections have been made on these dates. Sample descriptions and comments are based on information supplied by the submitters.
Nuclear Science and Technology Facility Radiocarbon Dates I
Authors: Thomas C C , Thomas F C
Published: July 2016

The Radiocarbon Laboratory began operation in mid-1972, using benzene synthesis. The equipment for the laboratory was obtained under a National Science Foundation Grant*. Basic equipment consists of a benzene synthesizer (Alford Instrument Co) and a liquid scintillation counter (Picker-Nuclear 220). The equipment is essentially identical with that of Noakes and Brandau (1971). Counting efficiency and background rates are also similar; ca 70% efficiency with a 4 to 5cpm background for 5ml benzene samples. Benzene synthesis is standard with sample combustion in pure oxygen under reduced pressure. The original synthesis system has been modified to permit simultaneous processing of more than one sample.
University of Miami Radiocarbon Dates XI
Authors: Piepgras D , Calvert M M , Stipp J J
Published: July 2016

The following dates are a partial list of geologic samples dated since December 1976. The method used is described by (Stipp et al, 1976). Ages were calculated using a half-life of 5568 years. Errors reported are one standard deviation and include only the counting errors on the unknown sample, background and modern standard. There have been no corrections made on these dates. Sample descriptions and comments were written, based on information supplied by the submitters.
A Procedure for the Preparation of Benzene from 14C Nbs Oxalic Acid Standard
Authors: Calf G. E.
Published: July 2016

A simple procedure for the conversion of 14C NBS oxalic acid standard to benzene without direct combustion or wet oxidation is reported. Fractionation in the synthesized benzene was not detected.
University of Pennsylvania Radiocarbon Dates XX
Authors: Fishman Bernard , Lawn Barbara
Published: July 2016

In this date list we have included most of the archaeologic samples dated in this laboratory since publication of our last date list (R, 1977, v 19, p 188-228).
University of Miami Radiocarbon Dates XIV
Authors: Calvert P M , Introne D S , Stipp J J
Published: July 2016

The following radiocarbon dates are a partial list of samples measured since January 1978. The chemical, counting and calculation procedures are the same as indicated in R, v 20, p 000-000.
Measurement of the 14C Activity of the ANU Sucrose Secondary Standard by Means of the Proportional Counter Technique
Authors: Srdoc Dušan , Obelic Bogomil , Horvatincic Nada , Sliepcevic Adela
Published: July 2016

A systematic crosschecking of the NBS oxalic acid standard, the ANU Sucrose secondary standard, and the RB oak tree rings grown in 1858 ± 5 and 1890 ± 5 has been performed using the proportional counter technique. Details on the counter gas (methane) purification are given. Corrections of count rates due to changes of barometric pressure and ambient temperature are applied and discussed. Results of measurements are presented and the ratios between mean activities of the NBS oxalic, ANU sucrose and RB oak samples are given.
GEOSECS Atlantic Radiocarbon
Authors: Stuiver Minze , Östlund H G
Published: July 2016

The program called Geochemical Ocean Section Study (GEOSECS) was initiated in 1971 and designed to make an oceanic inventory of chemical constituents in the world oceans, partly as a baseline study for future chemical changes, and partly to investigate large-scale oceanic transport and mixing processes. Measured were hydrographic parameters (salinity, temperature, and oxygen vs depth), the carbonate system, the nutrients, and assorted other constituents with heavy emphasis laid on the radioactive substances, radiocarbon, tritium, and radon.
Moscow MV Lomonosov State University Radiocarbon Dates I
Authors: Glushankova N I , Parunin O B , Timashkova T A , Khait V Z , Shlukov A I
Published: July 2016

The following list sums up the results of radiocarbon age determinations obtained at the Laboratory in 1974-1975. The list is prefaced with a brief description of the measurement procedure and discussion of some methodological aspects of the investigation that result in a higher accuracy of dating.
University of Wisconsin Radiocarbon Dates XVII
Authors: Bender Margaret M , Baerreis David A , Bryson Reid A
Published: July 2016

Procedures and equipment have been described in previous date lists. Except as otherwise indicated, 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.
UCR Radiocarbon Dates III
Authors: Taylor R E
Published: July 2016

This list reports a portion of the analysis completed on archaeologic and paleo-environmental samples measured in the UCR laboratory between August 1974 and August 1976. Results of measurements made during that period on sample suites which are not as yet completed or lack review by submitters will be reported in a subsequent date list.
University of Wisconsin Radiocarbon Dates XIX
Authors: Bender Margaret M , Baerreis David A , Bryson Reid A , Steventon Raymond L
Published: July 2016

Procedures and equipment have been described in previous date lists. Except as otherwise indicated, wood, charcoal and peat samples are pretreated with dilute NaOH–Na4P2O7 and dilute H3PO4 before conversion to the counting gas methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HCl instead of H3PO4. Pretreatment of bone varies with the condition of the bone sample, solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCl for 15 minutes, then dilute NaOH–Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted by Longin's method (Longin, 1971). Charred bone is treated with dilute HCl, NaOH–Na4PO7, and then dilute HCl again.
University of Lund Radiocarbon Dates XV
Authors: Håkansson Sören
Published: July 2016

Most of the 14C measurements reported here were made between October 1980 and October 1981. Equipment, measurement, and treatment of samples are as reported previously (R, 1968, v 10, p 36–37; 1976, v 18, p 290; 1980, v 22, p 1045).
British Museum Natural Radiocarbon Measurements XV
Authors: Burleigh Richard , Ambers Janet , Matthews Keith
Published: July 2016

The following list consists of dates for archaeologic and geologic samples mostly measured over the period from January 1980 to June 1981. The dates were obtained by liquid scintillation counting of benzene using the laboratory procedures outlined in previous lists (see, eg, BM VIII, R, 1976, v 18, p 16).
Gif Natural Radiocarbon Measurements IX
Authors: Delibrias Georgette , Guillier Marie-Thérèse , Labeyrie Jacques
Published: July 2016

The following list includes 14C measurements of geologic samples, the majority of which pertain to sea-level variations, and of archaeologic samples mainly from France, West Africa, and South America. Most of the dates were measured between 1972 and 1973 when installations were not modified. The technique used is described in Radiocarbon, 1972, v 14, p 280–320. Dates were calculated using the 14C half-life of 5568 years; modern standard is 0.95 of the NBS oxalic acid. Reported errors are one standard deviation for 2000 minutes measurements.
Simon Fraser University Radiocarbon Dates I
Authors: Nelson D E , Hobson K A
Published: July 2016

The SFU Archaeology Department has constructed a small radiocarbon dating facility to serve its own needs and, to the extent that time is available, the needs of other archaeologists and earth scientists. All dates reported here were processed by our laboratory from October 1979 to September 1980. The 14C measurements are made using conventional techniques for liquid scintillation counting of benzene. The samples are burned in a Phonon Mark IV combustion bomb and the resultant CO2 is purified and converted to Li2C2 using a reaction vessel based on the design of Polach, Gower, and Fraser (ms). Acetylene is formed by hydrolysis with distilled H2O which has been aged for a minimum of three months. The acetylene is trimerized to benzene with the Mobil Durabead I catalyst. The conversion efficiency of CO2 to C6H6 is typically 95%. Gas chromatographic analysis of typical samples of the synthesized benzene indicates 99.8% purity with toluene produced in trace amounts.
GEOSECS Indian Ocean and Mediterranean Radiocarbon
Authors: Stuiver Minze , Östlund H G
Published: July 2016

This paper is the third of a series detailing the general features of 14C distribution in the world oceans. In the preceding papers, we discussed the 14C activities of Atlantic and Pacific Ocean waters (Stuiver and Östlund, 1980; Östlund and Stuiver, 1980). We now give an outline of the 14C distribution of the Indian Ocean and profiles for one Mediterranean and three Red Sea stations.
ANU Radiocarbon Date List X
Authors: Polach Henry , Barton Charles
Published: July 2016

14C ages were obtained for the Australian lakes recorded below in order to complement research into their magnetic stratigraphy and sedimentology. It has been possible to establish precise 14C chronologies in six separate lakes, and also to compare ages obtained from stratigraphically equivalent horizons in different parts of the same lake so as to determine the reproducibility of these ages.
High-Precision 14C Measurement of Irish Oaks to Show the Natural 14C Variations from 200 BC to 4000 BC
Authors: Pearson G W , Pilcher J R , Baillie M G L
Published: July 2016

Bi-decade samples of dendrochronologically matched Irish Oak, measured with a precision of ca ± 20 years, covering the period 200 to 4000 BC are presented. The data are compared with the published data of Suess, de Jong, and Mook to provide a general calibration of the 14C time scale for this period. Although the dendrochronologic sequences presented are not absolutely tied to present, the best fit (based on 14C evidence) of the Belfast data to absolute chronologies, the error and evidence associated with such positioning is given. The intervals chosen for analysis were 20 years, reducing slightly the resolution of short-term variations when compared to 10-year intervals, which are sometimes measured. However, this calibration would suffice for most scientific purposes and certainly for the calendrical conversion of 14C dates derived from archaeologic samples.
Temporal 10Be Variations in Ice
Authors: Beer Juerg , Andree Michael , Oeschger Hans , Stauffer Bernhard , Balzer Richard , Bonani Georges , Stoller Christian , Suter Martin , Woelfli Willy , Finkel Robert C
Published: July 2016

10Be (T1/2 = 1.5·106y) is mainly produced in the atmosphere by cosmic ray spallation reactions on nitrogen and oxygen. About 70 % of the production takes place in the stratosphere. 10Be becomes attached to aerosols within a very short time. If 10Be is produced in the stratosphere some latitudinal mixing occurs. Most of the 10Be is transferred to the troposphere during spring and early summer when, mainly at median latitudes, large stratospheric air masses enter the troposphere. Tropospheric 10Be is deposited rapidly on the earth's surface by precipitation. The mean residence time of 10Be in the atmosphere is ca 1 to 2 years. 10Be removed from the atmosphere by precipitation is either preserved in snow and ice layers, in the topsoil and the biosphere, or it enters the hydrosphere (oceans and lakes), where it is transported to the sediments.
The Unreliability of 14C Dates Obtained from Buried Sandy Podzols
Authors: Geyh Mebus A , Roeschmann Günter , Wijmstra T A , Middeldorp A A
Published: July 2016

A test for the reliability of 14C dating of soil was made at two sites with buried, autochthonous, and in parts, allochthonous sandy podzols, dated either litho- and pedostratigraphically or palynologically. The differences between the age ranges obtained and the apparent mean residence times (AMRT) calculated from the 14C content of alkaline extracts from fossil soil layers and horizons lean in organic matter exceed 10,000 years, corresponding to a maximum contamination with recent carbon of up to 50 %. The use of correction factors for the apparent mean residence times of podzols is not valid, not even for climate zones, because these values have a broad scatter for the same profile.
Radiocarbon Measurements of Particulates in Smog
Authors: Berger Rainer , Johnson R M , Holmes J R
Published: July 2016

In recent years in California, smog aerosols have been observed in metropolitan and rural areas. We wondered what the relative contribution is from sources such as fossil fuel combustion (eg, cars, factories) and emissions from trees and other plants. Pollution produced by fossil fuel combustion can be distinguished from biological sources using radioactive carbon. Carbon in fossil organic materials is radioactively dead whereas carbon in living plants contains 14C. Smog particles were collected on clean glass or quartz fiber paper and analyzed in a small volume CO2 proportional counter for 14C content. Results are given for sampling locations at UCLA, El Monte, Riverside, and Lake Tahoe showing the relative contributions of fossil and modern carbon sources ranging from 0 to 74% and 26 to 100% respectively.
Direct Bone Dating in a Small CO2 Counter
Authors: Berger Rainer
Published: July 2016

A small 200ml capacity CO2 proportional counting system has been developed which uses only 100mg of carbon for complete filling. Thus, with respect to the small quantities needed, it compares favorably to dedicated accelerators at significantly lower cost. The performance of this equipment is demonstrated using a variety of samples including some human bone fragments from La Jolla which had been estimated to be 28,000 years old by aspartic acid racemization analysis.
Recent 14C Measurements with the Chalk River Tandem Accelerator
Authors: Brown R M , Andrews H R , Ball G C , Burn Neil , Davies W G , Imahori Yoshio , Milton J C D , Workman Wayne
Published: July 2016

The Chalk River Tandem Accelerator Mass Spectrometry System has reached a state of reliable measurement of 14C using 2 to 5mg elemental carbon prepared by Mg reduction of CO2. For two comparisons of a near-modern unknown with the NBS oxalic acid standard we obtain a total error of ∼±4.5%, consisting of a random system error of about ±3.5% combined with the statistical counting error. Measurements have been made on 70 samples in 30 days of running time during the past year. Samples included deep rock carbonates, cosmogenic 14C in meteorites, charcoal from earthquake fault zones, collagen of bone artifacts and fossil beetle-fragments.
The Oxford Radiocarbon Accelerator Facility
Authors: Gillespie Richard , Hedges R E M , White N R
Published: July 2016

The Oxford 14C accelerator has operated with beam for some 400 hours. This report describes the progress made towards achieving dates from milligram samples with the required accuracy of better than 2%. In summary, it shows how 14C is relatively easily detected, but that the overall beam optical system is, at present, rather sensitive to effects which prevent reliable maintenance of the necessary isotope ratio stability. These effects can probably be eliminated by careful attention to details of the design rather than by major modifications.
Ingeis Radiocarbon Laboratory Dates I
Authors: Albero Miguel C , Angiolini Fernando E
Published: July 2016

The Instituto de Geocronología Geología Isotópica (INGEIS) belongs to the Consejo Nacional de Investigaciones Cientifícas y Técnicas (CONICET) of Argentina and is supported by another six government institutions. Its headquarters are located in the Facultad de Ciencias Exactas y Naturales of the Universidad de Buenos Aires.
University of Miami Radiocarbon Dates XXIII
Authors: Hood D G , Johnson R A , Stipp J J
Published: July 2016

The following radiocarbon dates are a partial list of samples measured for a variety of projects and materials since May 1982. Chemical and counting procedures remain the same as indicated in R, v 20, p 274–282.

Calculations are based on the 5568-year Libby 14C half-life. Precision is reported as one-standard deviation based only on statistical counting uncertainties in the measurement of the background, NBS modern standard, and sample activities. δ13C values are measured relative to PDB and reported ages are corrected for isotopic fractionation by normalizing to −25‰.
Consensus δ13C Values
Authors: Burleigh Richard , Matthews Keith , Leese Morven
Published: July 2016

Selected stable carbon isotope measurements published in Radiocarbon over a 12-year period have been abstracted, plotted, and summarized, to give more reliable estimates of the mean value and range of δ13C for five classes of natural material (human bone collagen, non-human animal bone collagen, plant materials, wood, and charcoal), and to provide a firmer base line for stable carbon isotope dietary and environmental studies.
Radiocarbon—A Direct Calculation of the Period of the Grand Trend
Authors: Carmi Israel , Sirkes Ziv , Magaritz Mordeckai
Published: July 2016

A major collective effort was made to develop a data base for establishing the relationship between 14C and calendric ages (Stuiver, 1982). The early “cosmic schwung” fit between the two ages (Suess, 1970a, p 310) and the 10,350 yr period of the grand trend (Suess, 1970b, p 596) have recently been replaced by the period of 12,100 yr (Suess, 1980). The period of the grand trend was estimated by correlating the data with an a priori postulated sine function (Suess, 1970, p 596), or more recently a polynomial fit of the sixth degree was used (Klein et al, 1982). In the detrended data, periods (wiggles) of between 2400 yr and 104 yr were identified by conventional time series analysis. This approach could not be used to estimate the period of the grand trend, because the time series includes less than one cycle, whereas several cycles are required in order to get a meaningful result.
Hamburg University Radiocarbon Dates IV
Authors: Scharpenseel H W , Schiffmann Heinrich , Becker Peter
Published: July 2016

This list consists of dates of soil samples from selected soil profiles in Tunisia, Sudan, and Argentina. The profiles from Tunisia were taken to elucidate ages of typic paleosols of paleoclimatic significance. The Sudan profiles increase our understanding of pedogenesis of Sudanese Vertisols. The existence of pedoturbation in these profiles is further explored and questioned. The profiles of Argentina were dated to supplement information from chemical and micromorphological studies.
Simon Fraser University Radiocarbon Dates III
Authors: Hobson K A , Nelson D E
Published: July 2016

This list reports measurements made on archaeologic and geologic samples by our laboratory from June 1982 to December 1983. Results of measurements made during that period which lack review by submitters will be reported in a subsequent date list. Sample preparation techniques and benzene synthesis remain as described previously (R, 1982, v 24, p 344–351). For low organic samples, such as sediments, we now use a combustion tube assembly. These samples are burned under oxygen flow in a quartz tube. To absorb sulfur and break up nitrous compounds, we pass combustion gases through a 50% mixture of MnO2 and CuO wire heated to ca 500°C. The gas is then bubbled through a distilled water and KMnO4 solution to remove chlorides before being introduced into our standard dry ice and CO2 traps.
25 Years of Tropospheric 14C Observations in Central Europe
Authors: Levin Ingeborg , Kromer Bernd , Schoch-Fischer Hildegard , Bruns Michael , Münnich Marianne , Berdau Dietrich , Vogel John C , Münnich Karl Otto
Published: July 2016

A long-term mountain station series of tropospheric 14C data for the period 1959 to 1984 is presented. This series is considered representative of the higher altitude14C level over central Europe. Even tree-ring 14C levels from a rural ground level site in southern Germany are consistently lower (by Δ14Cdepression = −15‰ if compared with the mountain station summer average in atmospheric CO2). The rural tree-ring series is considered to represent the additional continental Suess effect at ground level without local contamination. This Suess effect decreases gradually with the distance from the ground (ie, source) level. We therefore estimate the additional continental Suess effect in the vegetation period to be Δ14Cdepression = −5‰ for the mountain station and −20‰) for a rural ground level site, respectively. Based on this assumption, yearly mean tropospheric 14C levels corrected for fossil fuel contamination and representative of the Northern Hemisphere are provided for use in global carbon cycle models.
La Jolla Measurements of Radiocarbon in South German Oak Tree-Ring Chronologies
Authors: Linick T W , Suess H E , Becker Bernd
Published: July 2016

Radiocarbon measurements made by the La Jolla laboratory on tree-ring samples from South German oak chronologies are presented. Several previously separate tree-ring series have been reduced to one absolutely dendro-dated chronology spanning the period from 4066 BC to the present and one still-floating chronology which spans the approximate period 7225 to 4125 BC. Previous estimates of the dendro-years made by the authors are compared with the dendro-years now assigned.
Gliwice Radiocarbon Dates X
Authors: Pazdur Mieczysław F , Awsiuk Romuald , Bluszcz Andrzej , Goslar Tomasz , Pazdur Anna , Walanus Adam , Zastawny Andrzej
Published: July 2016

The following list contains all age measurements of paleoenvironmental samples made from 1978 to the end of 1982 for the IGCP 158 Project “Paleohydrological changes in the temperate zone in the last 15,000 years,” Subproject B “Lake and mire environments” (Berglund, 1979), initiated by Bjorn Berglund and Leszek Starkel in 1976. The aim of this project was to reconstruct environmental changes related to climate and human activity in the temperate zone of Asia, Europe, and North America. Broad environmental reconstructions will be based upon a network of reference sites representing the natural geographic regions, distinguished by their geology, climate, vegetation, and other natural factors, according to Berglund (1979). The subdivision of Poland into 29 paleoecological units according to Ralska-Jasiewiczowa (1982) is presented in table 1, and in figure 1 where reference sites dated by 14C in our lab are also indicated.
A Review of the Operation of the Oxford Radiocarbon Accelerator Unit
Authors: Batten R J , Bronk C R , Gillespie Richard , Gowlett J A J , Hedges Rem , Perry Colin
Published: July 2016

We describe here the general operation of the Oxford Radiocarbon Accelerator Laboratory which has now been dating routinely for 18 months.
Production of Graphite Targets by Deposition from CO/H2for Precision Accelerator14C Measurements
Authors: Jull A J T , Donahue D J , Hatheway A L , Linick T W , Toolin L J
Published: July 2016

A method has been developed at the Arizona AMS facility for production of graphite directly from CO2by catalytic reduction of CO/H2mixtures. The method is a modification of procedures discussed by Vogelet al(1984). Currents of12C−from these targets vary considerably, but have a median value which is 70% of that achieved from spectroscopic graphite. Precisions of ±60 to 100 yr are routinely achieved for14C ages of 5000-yr-old samples containing one milligram of carbon. The yield of14C from “blank” targets is 0.6 ± 0.1% of that from modern material.
Accelerator Mass Spectrometry with Fully Stripped 36Cl Ions
Authors: Haberstock Günther , Heinzl Johann , Korschinek Gunther , Morinaga Haruhiko , Nolte Eckehart , Ratzinger Ulrich , Kato Kazuo , Wolf Manfred
Published: July 2016

A description of accelerator mass spectrometry (AMS) measurements with the long-lived radioisotope 36Cl is given. All measurements were made at the Munich tandem accelerator laboratory. Results are presented for 36Cl measurements in ground waters, in the meteorite Bjurböle, in ice-core samples of the Vernagtferner, Austria, and in granite samples from Hiroshima, Japan, irradiated by the atomic bomb explosion in 1945.
Geomagnetic-Heliomagnetic Modulation of Atmospheric Radiocarbon Production
Authors: Damon Paul E , Linick Timothy W
Published: July 2016

New Arizona high precision Δ14C data back to 6500 BC plot close to an 11,300-yr period sinusoid extrapolated from the post 5300 BC data (offset = +32‰, half amplitude = 51‰ and phase lag = 2.29 radians). The trend curve is modulated by high latitude components of the non-dipole field with a fundamental period of 2400 yr. Based upon a model of Lund and Banerjee (1985), the non-dipole field rotates and every 1200 yr the high latitude maxima pass over the north magnetic pole and near the south magnetic pole in reversed polarity. This modulates cosmic ray production producing extended maxima ca AD 1700, 700 bc, 3100 bc, and 5500 bc. The 2400 period appears to be stationary. The magnetic field also modulates the amplitude of the solar activity induced cycles of periods 200, 80, and 11 yr as can be seen in the Zürich-Bern Camp Century ice core data as well as in the Δ14C fluctuation data. Reinterpretation of the Camp Century10Be data indicates that it is in agreement with magnetic field as well as solar activity modulation of terrestrial radioisotope production.
Dendrochronology—The Absolute Irish Standard
Authors: Brown D M , Munro M A R , Baillie M G L , Pilcher J R
Published: July 2016

Since the 11th International Radiocarbon Conference considerable advances have been made in European dendrochronology giving several long continuous absolute chronologies. Recent collaboration between European laboratories provides confirmation of the accuracy of these chronologies and, thus, of the standards used for radiocarbon calibration.
Annual Variations of the 14C Content of Soil CO2
Authors: Dörr Helmut , Münnich K O
Published: July 2016

A 6-year and a 2-year record of 14C measurements of soil CO2 in two soils are presented and discussed. The annual 14C variation of soil CO2 is controlled by the seasonally varying contribution of root respiration and of microbial decomposition of organic matter producing soil CO2. The Δ14C soil CO2 difference between summer and winter is ca 50‰ in a soil where turnover of organic matter is fast (τ = 2.5a) and ca 100‰ in a soil of slow turnover (τ = 60a). A simple model describing the movement and turnover of organic matter is derived, giving the depth distributions of organic carbon and of 14C. The model needs a subdivision of the carbon reservoir into at least two reservoirs with residence times of τ1 = la and τ2 = 100a, respectively, and with a vertical transfer velocity in the order of 0.6mm/a.
Bomb Produced14C Content in Tree Rings Grown at Different Latitudes
Authors: Dai Kai-Mei , Fan C Y
Published: July 2016

The14C content in 1961–1967 rings of each of three spruce pines grown at (68° N, 130° W), (47° 30' N, 129° 16' E) and (27° 13' N, 100° 20' E) were measured. Δ14C values of the three specimens rise dramatically from a common level (∼250‰) in 1961 to their respective maxima, 964‰, 909‰, and 743‰ in 1964 and then fall to a common level ∼680‰ in 1967. The observed Δ14C increase comes most likely from the nuclear bomb test of the USSR at 75° N in 1961, although there were many other tests since the 1950s. The different effects at different latitudes reflect the atmospheric circulation patterns in the stratosphere and the transport of14C nuclei from the stratosphere to the troposphere.
14C Depth Profiles as Indicators of Trends of Climate and 14C/12C Ratio
Authors: Brown Robert H
Published: July 2016

Composite curvature averages for 14C age depth profiles of deep ocean sediment, continental sediment, and soil each indicate a global trend for 14C age increment per cm depth to increase with 14C age over the range for which a definitive statistical sample is available. The global trend indicated for peat profiles is constant 14C age increment per cm depth over the past 10,000 14C yr. Correlation coefficients between changes in 14C yr/cm and maximum profile thickness contradict compaction as an adequate explanation for the global trend indicated by sediment and soil profiles. This trend must be explained by additional factors such as progressively decreasing contamination from older carbon, increasing cosmic ray intensity, decreasing geomagnetic intensity, diminishing 12C in the active biosphere during profile accumulation, and climate factors affecting the rate of accumulation. The diverse trend of peat profiles may indicate climatic conditions more favorable to peat growth during the earlier portion of the past 10,000 yr.
The Chemical Preparation of AgCl for Measuring 36Cl in Polar Ice with Accelerator Mass Spectrometry
Authors: Conard N J , Elmore David , Kubik P W , Gove H E , Tubbs L E , Chrunyk B A , Wahlen Martin
Published: July 2016

A method of chemical separation and purification of chloride from relatively small samples (500 to 2100g) of glacial ice is presented. With this procedure the first successful measurements of pre-bomb levels of 36Cl in Greenland ice have been made. Emphasis is placed on methods of reducing sulfur, which causes interference in the accelerator mass spectrometry, and in maximizing the yield. Data regarding the selection of materials for sample holders and the use of metal powders for extending the lifetime of the sample are also presented.
An Intercomparison of Some AMS and Small Gas Counter Laboratories
Authors: Burleigh Richard , Leese Morven , Tite Michael
Published: July 2016

The performance of six laboratories with the capacity to date small samples (4 AMS and 2 small gas-counter laboratories) has been compared using 100mg samples of textiles from Ancient Egypt and Peru, with the British Museum laboratory acting as independent coordinator. This intercomparison was one of normal practices and has demonstrated that a coherent series of results can be obtained when several laboratories undertake blindfold measurements, although the occurrence of outliers emphasizes the continuing need for the dating of unusually important or controversial samples to be undertaken by a group of laboratories.
Background Measurements with Different Shielding and Anticoincidence Systems
Authors: Loosli H H , Forster Markus , Otlet R L
Published: July 2016

Extremely low background count rates are a necessary condition for both the measurement of 39Ar concentrations in ground and ocean water and of 14C activities in small samples using gas proportional counting techniques. A systematic comparison of the performance of three different designs of shielding systems in four different installations has been made.

Background values of selected gas proportional counters were measured, compared and separated into their various components. Acceptably low backgrounds were obtained in all the systems tried. The performance of a NaI shield in a surface laboratory was found to be at least equal to the best obtained with a gas anticoincidence detector in a deep underground laboratory.
Global and Local Effects of14C Discharges from the Nuclear Fuel Cycle
Authors: McCartney Martin , Baxter M S , McKay Keith , Scott E Marian
Published: July 2016

The radiologic impact of14C produced by the nuclear fuel cycle is assessed at both global and local levels. In the former context, it is predicted here that the specific activity of atmospheric CO2in the year 2050 will be ca 7.6 pCig-1C. Although this is similar to the present level, the subsequent collective dose commitment could be highly significant.

The enhancement of14C concentrations around the nuclear fuel-reprocessing plant at Sellafield (Windscale) in Cumbria, U K has been monitored over recent years. For example, maximum levels of 27.2 pCig-1C (∼350% above natural) during 1984 were observed < 1 km from the plant, with enhanced activities detectable to at least 29km. Nevertheless, it is clear that the radiologic significance to the local population is low. The spatial distribution of the excess14C allows atmospheric dispersion models to be tested in the context of continuous releases and the results thus far show that the Gaussian plume model performs successfully.
Regional Suess Effect in the Upper Silesia Urban Area
Authors: Awsiuk Romuald , Pazdur Mieczysław F
Published: July 2016

The study of a regional Suess effect is based on three sets of samples of atmospheric CO2: 1) a series of samples collected at the same site in Gliwice from 1980 to 1984, 2) samples collected simultaneously at different sites within the limits of an urban and industrial region of Upper Silesia, and 3) samples collected simultaneously outside this region along an eastern direction. Results of14C concentration measurements show systematic decrease of Δ14C with the rate close to the corresponding value for clean air. Depletion of14C concentration was found to be virtually the same in the whole urban area. Analysis of regional synoptic data reveals correlation of individual Δ14C values with wind direction, frequency of calm, and vertical stability of the atmosphere.
Radiocarbon Concentration of California Aerosols
Authors: Berger Rainer , McJunkin David , Johnson Roberta
Published: July 2016

In this study the origin of the carbonaceous fraction of total suspended particles (TSP) in air was analyzed. While the summer data show increasing carbon concentrations in the Los Angeles air basin from west to east, in the winter high levels of carbon particles can be found over the coast. The smallest and most dangerous particle fraction is principally composed of fossil carbon.
The Power of 14C Measurements Combined with Chemical Characterization for Tracing Urban Aerosol in Norway
Authors: Currie L A , Klouda G A , Schjoldager Jørgen , Ramdahl Thomas
Published: July 2016

Changing fuel patterns and increased awareness of health effects from combustion aerosols have generated considerable interest in the use of 14C as a biogenic-fossil aerosol source discriminator. Prior studies in the US demonstrated the importance of 14C measurement for estimating the wood-burning contribution to urban aerosols. The present work treats a specific air-pollution problem in the town of Elverum, Norway where large wintertime concentrations of aerosol carbon and polycyclic aromatic hydrocarbons (PAH) were suspected to come from residential wood combustion (RWC). The problem was significant in that up to 50/μg/m3[C] and 490ng/m3[PAH] were found during pollution episodes. Samples collected during two winters were analyzed for 14C, C, PAH, and several elements in the fine fraction (<3μm) aerosol. Source apportionment based on these species indicated an average of ca 65% RWC-carbon (14C), ca 5% fine particle mass from motor vehicles (Pb), but negligible contributions from heavy fuel oil (Ni, V). Patterns of 14C and total C, examined as a function of temperature and PAH, indicated large increases in RWC aerosol on the coldest days, and a major RWC contribution to the PAH fraction. Patterns with inorganic species implied multiple tracer sources, and one important case of long-range transport.
Isotopic Fractionation of Carbon During CO2 Absorption by Mortar
Authors: Pachiaudi Christiane , Marechal Joelle , Van Strydonck Mark , Dupas Michel , Dauchot-Dehon Michelle
Published: July 2016

Recent studies comparing dates from the carbon content of mortars with dendrochronologic dates for the same material have shown considerable inconsistencies related to mortar type (Van Strydonck et al, 1985). Even after the best possible removal of “dead” calcite, some mortars are unsuitable for dating. We describe here our experimental study of carbon isotope fractionation during the manufacture and hardening of mortars. Preliminary experiments established overall uptake of CO2 from the air. We then measured isotopic ratios in identical mortars at different hardening times.
Discordant Ages Related to Reservoir Effect of Associated Archaeologic Remains from the Tunel Site, Beagle Channel, Argentine Republic
Authors: Albero Miguel C , Angiolini Fernando E , Piana Ernesto L
Published: July 2016

Evidence of a tradition of human maritime adaptation was recovered from various sites at Beagle Channel dating back to ca 6000 yr BP. Final occupations date to European settlement in the 19th century. The Túnel site exhibits discontinuous human occupation ranging from 6000 to 500 yr BP, represented by different archaeologic remains in each layer. Associated charcoal, mollusk shells, andLama guanicoeandArctocephalus australisbones were dated. Shells andArctocephalusare consistently older than charcoal, demonstrating the reservoir effect at Beagle Channel. Results encourage further work in the area to evaluate the spatial and temporal magnitude of the effect.
Algiers Radiocarbon Measurements I
Authors: Rahmouni O. , Roussillot C. , Armanet F.
Published: July 2016

The following list shows the age measurements made at Algiers by the Service des Applications Nucléaires using the C14 method. The laboratory was created in 1965 to answer the increasing demand of the archaeologic research in N Africa, and made its first measurements in 1967. The electronic apparatus employed was completed and calibrated in 1968 and the first tests were performed during the same year. Regular dating-test samples started in June, 1968. The electronic circuits are of commercial origin or made in the C14 Laboratory.
Bern Radiocarbon Dates VII
Authors: Oeschger H. , Riesen T. , Lerman J. C.
Published: July 2016

This list contains a selection of dates from analyses carried out during the past few years. Samples are grouped in geologic-palynologic, and archaeologic sections according to main problem. When influence of human activity on pollen diagrams has been observed it has been explicitly indicated. The descriptions and comments have been written in collaboration with collectors and submitters. For the samples from Switzerland, general reference has also been made to Welten (1958a) and to sections on palynology, geology, and archaeology in work edited by the Schweizerische Gesellschaft für Ur- und Frühgeschichte (1968-1970).
GIF Natural Radiocarbon Measurements V
Authors: Delibrias G. , Guillier M. T. , Labeyrie J.
Published: July 2016

The list given below contains the C14 dates obtained for only archaeologic samples, during 1966 and 1967; for the study of the geologic samples dated during the same period, cf. our previous list Gif-III (Radiocarbon, 1969, v. 11, p. 327-344). The same instruments and techniques have been employed.
Riken Natural Radiocarbon Measurements VI
Authors: Yamasaki Fumio , Hamada Tatsuji , Hamada Chikako
Published: July 2016

The C14 dates given below are a continuation of the work presented in our previous list (Radiocarbon, 1969, v. 11, p. 451-462), and results obtained mainly during 1969 are described. A new 3.3 L copper counter was put into routine operation besides the 2.7 L stainless steel counter employed heretofore, yielding background counting rates of 8.5 and 5.5 cpm, respectively, when filled with dead CO2 at ca. 1.8 atm.
University of Texas at Austin Radiocarbon Dates VIII
Authors: Valastro S. , Davis E. Mott
Published: July 2016

This list reports C14 measurements made in projects completed in the year ending October, 1969, and some measurements for projects still in progress. Age calculations are based on C14 half-life of 5568 years and a modern standard of 95% of NBS oxalic acid. Deviations reported are based on counting statistics of sample, background, and modern, and are ± 1σ except that when sample count approaches either modern or background, 2σ limits are reported. The laboratory uses liquid scintillation counting of benzene, with Li2C2 and vanadium activated catalyst in preparation. Chemical yields average 88%.
University of Rome Carbon-14 Dates IX
Authors: Alessio M. , Bella F. , Improta S. , Belluomini G. , Cortesi C. , Turi B.
Published: July 2016

This list includes age measurements carried out from November 1969 to December 1970. All archaeologic and geologic samples come from Italian territory. Laboratory equipment, largely unchanged, has been described (Alessio et al., 1970).