RSS 1.0Radiocarbon, Volume 37, Number 2 (1995)
ABOUT THIS COLLECTION
Radiocarbon is the main international journal of record for research articles and date lists relevant to 14C and other radioisotopes and techniques used in archaeological, geophysical, oceanographic, and related dating.
This archive provides access to Radiocarbon Volumes 1-54 (1959-2012).
As of 2016, Radiocarbon is published by Cambridge University Press. The journal is published quarterly. Radiocarbon also publishes conference proceedings and monographs on topics related to fields of interest. Visit Cambridge Online for new Radiocarbon content and to submit manuscripts.
ISSN: 0033-8222
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Recent Submissions
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Radiocarbon, Volume 37, Number 2 (1995)Department of Geosciences, The University of Arizona, 1995-01-01
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Sixth Australasian Archaeometry ConferenceDepartment of Geosciences, The University of Arizona, 1995-01-01
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Conference ParticipantsDepartment of Geosciences, The University of Arizona, 1995-01-01
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AcknowledgmentsDepartment of Geosciences, The University of Arizona, 1995-01-01
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7th International Conference on Accelerator Mass SpectrometryDepartment of Geosciences, The University of Arizona, 1995-01-01
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1996 Price ListDepartment of Geosciences, The University of Arizona, 1995-01-01
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Subject IndexDepartment of Geosciences, The University of Arizona, 1995-01-01
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Use of Bomb-Produced 14C to Evaluate the Amount of CO2 Emanating from Two Peat Bogs in FinlandWe used moss increment counting to obtain well-defined samples of the topmost peat layers of two Sphagnum fuscum hummocks. The two ombrotrophic bogs, Lakkasuo in central Finland and Korvinsuo in eastern Finland, are of different ages, covering 3 and 9 ka, respectively. Using AMS dating, we traced bomb-produced 14C through the topmost parts of the two peat profiles. A well-defined 14C activity peak was found in both sequences dating the corresponding layer to AD 1965. A comparison between the maximum peat activities and the corresponding atmospheric values for the period of interest provides an opportunity to evaluate the amount of CO2 emanating from the decaying peat bog, and taken up by the living sphagnum plants. Considerable variations in delta-13C values were also observed. These variations indicate, at least partly, annual variations in the emission rate of CO2 from decomposition of older peat in the bog, and are connected with climatic factors such as temperature and precipitation.
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The Swedish Time Scale: A Potential Calibration Tool for the Radiocarbon Time Scale During the Late WeichselianThe Swedish Time Scale (STS) is a ca. 13,300-yr-long varve chronology that has been established for the Swedish east coast from >1000 overlapping clay-varve diagrams. We describe the present state of the STS and illustrate the application of this worldwide unique varve chronology for AMS radiocarbon measurements. The results are compared to other 14C-dated calendar-year chronologies: dendrochronology, laminated lake sediments and U/Th. Our data set agrees with the oldest part of the dendrochronological calibration curve, and with AMS 14C-dated lake lamination data and U/Th on corals down to ca. 12 ka calendar years BP. Further back in time, the AMS-dated part of the STS partly compares well with lake lamination chronologies and shows that the difference between 14C and calendar years decreases rapidly between 12,600 and 12,800 calendar years BP. Such a development seems to contrast with U/Th measurements on corals. We suggest that the cause for the divergence among three supposed calendar-year chronologies lies in the fact that the data points on the marine 14C-U/ Th curve are more widely spaced in time than the tightly grouped set of terrestrial AMS 14C dates, and thus are not able to reflect short-term changes in atmospheric 14C. Therefore, we argue that the use of the pre-Holocene part of the calibration program is premature and inadvisable.
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The Use of Zeolite Molecular Sieves for Trapping Low Concentrations of CO2 from Environmental AtmospheresWe describe a simple method for trapping low concentrations of CO2 present in gas mixtures, such as air and soil respiration, using a zeolite molecular sieve (type 13x) for environmental carbon isotope studies. We employ reusable molecular-sieve cartridges and a lightweight battery-driven pumping system, developed to enable CO2 collection in difficult and dangerous terrain or under extreme climatic conditions. The results of a small field experiment suggest that CO2 could be quantitatively trapped on and recovered from the 13x molecular sieve, without any fractionation of the stable carbon isotope. The delta-13C of CO2 was also independent of the amount of air less than or equal to 18 liters and rate at which it was collected, i.e. Less than or equal to 1 liter of air/min.
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The Occupation History of the Region Between the Dvina and Lovat Rivers in Relation to the Dynamics of Environmental ChangeWe show how 14C dating may be combined with palynological and paleogeographical research to correlate human occupation history with environmental change, focusing on archaeological sites in the Dvina-Lovat River region of Russia. Cultures in this region range from Early Neolithic to the Middle Ages, ca. 5500 BC-AD 100, based on calibrated 14C ages. The dynamics of water basins in the region, related to climatic change, are one cause of population migration.
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The HVEE 14C System at GroningenSince May 1994, a new-generation accelerator mass spectrometer (AMS) has been fully operational at the Centre for Isotope Research in Groningen, The Netherlands. The fully automated and high-throughput accelerator mass spectrometry (AMS) system, manufactured by High Voltage Engineering Europa (HVEE) is dedicated to radiocarbon analysis. The HVEE 4130 14C AMS is able to analyze up to 3000 samples per year. The system is characterized by simultaneous transport of all three isotopes (12C, 13C,14C) and 14C analysis with a precision below 0.5 pMC and a daily stability below 0.5 pMC. We present here a system description together with stability and performance measurements.
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Tell es-Sultan (Jericho): Radiocarbon Results of Short-Lived Cereal and Multiyear Charcoal Samples from the End of the Middle Bronze AgeSamples from Tell es-Sultan, Jericho, were selected for high-precision 14C dating as a contribution toward the establishment of an independent radiocarbon chronology of Near Eastern archaeology. The material derives from archaeological excavations conducted by K. M. Kenyon in the 1950s. We present here the results of 18 samples, associated stratigraphically with the end of the Middle Bronze Age (MBA) at Tell es-Sultan. Six short-lived samples consist of charred cereal grains and 12 multiyear samples are composed of charcoal. The weighted average 14C date of the short-lived grains is 3306 +/7 BP. The multiyear charcoal yielded, as expected, a somewhat older average: 3370 +/6 BP. Both dates are more precise than the standard deviation (sigma) of the calibration curves and the absolute standard of oxalic acid. Calibration of the above Jericho dates is a bit premature, because several groups are currently testing the accuracy of both the 1986 and 1993 calibration curves. Nevertheless, preliminary calibration results are presented for comparison, based on 4 different calibration curves and 3 different computer programs. Wiggles in the calibration curves translate the precise BP dates into rather wide ranges in historical years. The final destruction of MBA Jericho occurred during the late 17th or the 16th century BC. More definite statements about the calibrated ages cannot be made until the accuracy of available calibration curves has been tested. Development of calibration curves for the Eastern Mediterranean region would be important.
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The 14C Content of Modern Vegetation Samples from the Flanks of the Katla Volcano, Southern IcelandSamples of living terrestrial plants comprising a moss (Calliergon sp.), Carex spp. And Alchemilla spp. Were collected from the surface of the mire at Engimyri in Myrdalur, southern Iceland, 10 km from the crater rim of the central complex of the Katla volcano. This area is 16 km from the fissures active in AD 1918 and was directly affected by the tephra fall. Although there is no hot-spring or fumerole activity in the area, sufficient volcanic activity during the weeks preceding sample collection produced a strong sulphurous odor in the streams. As part of a large-scale dating program, we analyzed the modern vegetation to determine whether anomalies caused by the uptake of "old" volcanic CO2 were apparent. The results showed 14C values for the Calliergon sp., Carex spp, and Alchemilla spp, of 113.2 +/0.6 pMC, 113.03 +/0.52 pMC and 113.10 +/0.6 pMC, respectively. The delta-13C-PDB values were -28.7 per mil, -28.0 per mil and -27.0 per mil, respectively. Similar vegetation, i.e., terrestrial plants from a marsh environment in southern Scotland, were also analyzed as a comparison and gave 14C values of 113.16 +/0.55 and 112.98 +/0.59 pMC. The implication is that Icelandic vegetation at Engimyri is not affected by "old" carbon from volcanic emissions and dates obtained for this Icelandic peat are acceptable and directly comparable with Scottish Peat.
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The ANTARES AMS Centre: A Status ReportThe ANTARES accelerator mass spectrometry facility at Lucas Heights Research Laboratory is operational and AMS measurements of 14C, 26Al and Cl36 are being carried out routinely. Measurement of 129! recently commenced and capabilities for other long-lived radioisotopes such as 10Be are being established. The overall aim of the facility is to develop advanced programs in Quaternary science, global climate change, biomedicine and nuclear safeguards.
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Studies on Selected Proteins of Bone in ArchaeologyWith the advent of AMS radiocarbon dating of very small samples, a much greater opportunity now exists for research into specialized materials. Investigations of the proteins of bone and teeth for archaeological purposes suggest that much more information might be obtained by appropriate study of individual proteins in these tissues. Although present research seems limited to 14C dating, racemization and dietary selection, conditions of the environment during preservation and some of the physiological events during life are likely to be discernible through further studies.
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Stratified 14C Dates and Ceramic Chronologies: Case Studies for the Early Bronze Age at Troy (Turkey) and Ezero (Bulgaria)Prehistoric tell stratigraphies, like deep-sea sediments or peat deposits, store information about past atmospheric 14C variations. By matching the 14C ages on charcoal samples from settlement deposits with the tree-ring calibration curve, estimates for the time span covered by successive stratigraphic phases can be derived. This method is applied to 14C data from the tell mounds at Troy, Turkey and Ezero, Bulgaria. I compare the derived chronologies with the results of pottery shape seriation using correspondence analysis.
