Browsing Radiocarbon, Volume 32, Number 2 (1990) by Journal
Now showing items 1-18 of 18
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1993 Price ListDepartment of Geosciences, The University of Arizona, 1990-01-01
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AMS Radiocarbon Measurements on Foraminifera Shells from Deep-Sea CoresRadiocarbon ages determined by the AMS method on hand-picked foraminifera shells are reported. The results allow estimates of the ventilation rate of the deep Atlantic and Pacific Oceans during glacial time. They also extend our knowledge of the chronology of events associated with the transition from full glacial conditions ca 15,000 years ago to full interglacial conditions ca 8000 years ago. This and the previous lists (Broecker et al 1988c) contain all the results obtained as part of this program through the fall of 1989.
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Applicability of `New Technology' Scintillation Counters (Packard 2000 CA/LL and 2260 XL) for C4 DatingThe results of this study indicate that scintillation counters employing burst-counting circuitry are capable of producing accurate age measurements. Replicate analyses confirm the validity of the minimum error of 50-60 years quoted on routine age measurements carried out at this laboratory.
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Associate EditorsDepartment of Geosciences, The University of Arizona, 1990-01-01
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Calibrating New Zealand Radiocarbon Dates of Marine ShellsRadiocarbon activity of 11 modern marine shell samples from the New Zealand region is enhanced compared with the surface layers of the average world ocean. The measured enhancement, Delta-R, is equivalent to -31 +/13 years. On this basis, the Institute of Nuclear Sciences will now use a value of -30 years in reporting calibrated ages for marine shell samples.
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Call for AbstractsDepartment of Geosciences, The University of Arizona, 1990-01-01
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Isotope-Ratio and Background Corrections for Accelerator Mass Spectrometry Radiocarbon MeasurementsWe present here the method we use to convert to radiocarbon ages (14C/13C) ratios measured in the Arizona Accelerator Mass Spectrometer facility. We describe the procedures we use to convert sample and standard isotope ratios to values appropriate for calculation of radiocarbon ages. We also discuss, in some detail, corrections to account for sample contamination.
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Marine Turtle Bones from an Archaeological Site in Polynesia Yield Reliable Age DeterminationsAccelerator mass spectrometry dating of three 50g samples of marine turtle bone from the basal cultural stratum of the Tongoleleka archaeological site, Lifuka Island, Kingdom of Tonga, South Pacific yields results that agree with conventional 14C dates on marine shell. A method for calibrating these dates that takes into account the long distance migrations of marine turtles in the South Pacific is proposed. A sample size greater than 50g is recommended for routine AMS dating of marine turtle bone.
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Preparative High-Performance Liquid Chromatographic Separation of Individual Amino AcidsExtracting a series of amino acids from fossil "collagen" makes it possible to compare chemically well-characterized molecules from one bone sample, both chemically and by isotopic analysis. Thus, the integrity of collagen samples and possible contamination can be checked. We describe the routine high-performance liquid chromatographic extraction of five amino acids: glycine, hydroxyproline, lutamate, threonine and alanine. Humates are eliminated during the extraction, which can be monitored continuously.
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Price ListDepartment of Geosciences, The University of Arizona, 1990-01-01
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Radiocarbon Announces the Forthcoming Publication of the Following Special Issues:Department of Geosciences, The University of Arizona, 1990-01-01
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Radiocarbon, Volume 32, Number 2 (1990)Department of Geosciences, The University of Arizona, 1990-01-01
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Send for a Free Sample Copy of...Quaternary Science ReviewsDepartment of Geosciences, The University of Arizona, 1990-01-01
