Radiocarbon, Volume 37, Number 1 (1995): Recent submissions
Now showing items 1-20 of 21
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Radiocarbon, Volume 37, Number 1 (1995)Department of Geosciences, The University of Arizona, 1995-01-01
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Liquid Scintillation Spectrometry 1992Department of Geosciences, The University of Arizona, 1995-01-01
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Late Quaternary Chronology and Paleoclimates of the Eastern Mediterranean [Announcement]Department of Geosciences, The University of Arizona, 1995-01-01
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Friends of RadiocarbonDepartment of Geosciences, The University of Arizona, 1995-01-01
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Calibration 1993Department of Geosciences, The University of Arizona, 1995-01-01
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Associate EditorsDepartment 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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1995 Price ListDepartment of Geosciences, The University of Arizona, 1995-01-01
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The Younger Dryas Cold Event—Was it Synchronous Over the North Atlantic Region?Determined independently from annually laminated ice cores and lake sediments, and German pines, the calendar ages of Younger Dryas (YD) boundaries significantly disagree with one another. 14C dates, plotted vs. Calendar ages for samples from different sediments, also reveal distinct offsets. The adjustment of varve chronologies to synchronize the boundaries of the YD nearly cancels the discrepancies between 14C data, and supports the synchronism of the YD cold period over the North Atlantic region. However, the exact timing of the event cannot be estimated in this way.
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The 14C Age of the Icelandic Vedde Ash: Implications for Younger Dryas Marine Reservoir Age CorrectionsIncreased marine 14C reservoir ages from the surface water of the North Atlantic are documented for the Younger Dryas period. We use terrestrial and marine AMS 14C dates from the time of deposition of the Icelandic Vedde Ash to examine the marine 14C reservoir age. This changed from its modem North Atlantic value of ca. 400 yr to ca. 700 yr during the Younger Dryas climatic event. The increased marine reservoir age has implications for both comparing climatic time series dated by 14C and understanding palaeoceanographic changes that generated the increase.
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Storage Conditions and Physical Treatments Relating to the Dating of the Dead Sea ScrollsThe Dead Sea Scrolls have been analyzed by paleographic, non-destructive and destructive testing. The dates of their creation have been in dispute since their discovery. Research has established their authenticity, but a variety of conditions including the methods of skin preparation, variation in storage conditions and post-discovery restoration treatments could have introduced changes now affecting dating efforts. Comprehensive analyses were not possible until recently. Such analysis must be performed to establish a concrete framework for all the texts.
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Radiocarbon Dating the Holocene in the Gościąż Lake Floating Varve ChronologyTerrestrial macrofossils selected from laminated sediment of Lake Gościąż were dated by AMS. Thus, part of the floating varve chronology (FVC) (Goślar et al. 1993) between radiocarbon ages of 4225 +/45 and 7740 +/85 BP can be compared and placed on the 14C calibration curve. As a result of our dating, the top of the FVC is now dated between 3120 and 3300 cal BF, i.e., 3210 +/90 cal BP.
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Radiocarbon Dating of Scrolls and Linen Fragments from the Judean DesertWe report on new 14C measurements of samples of 18 texts (scrolls) and 2 linen fragments from Qumran Caves 1, 2, and 4 and from Naḥal Ḥever, both in the Dead Sea region. The radiocarbon results are in good agreement with estimates of age based on paleography.
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Radiocarbon Dating Evidence for Mammoths on Wrangel Island, Arctic Ocean, Until 2000 BCRadiocarbon dating results of mammoth tusks, teeth and bones collected on Wrangel Island between 1989 and 1991 reveal a unique mammoth refugium during the Holocene. We used an improved chemical procedure to obtain and purify collagen from bone. Benzene synthesized from the samples was measured using a liquid scintillation counter. The validity of our data has been confirmed by the results of our measurements on two international control sample series (IAEA and TIRI) and by parallel measurements of Wrangel Island mammoth remains at other laboratories.
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Problems in the Extension of the Radiocarbon Calibration Curve (10-13 Kyr BP)Radiocarbon dating of varved lake sediments shows that, during the Late Glacial (10-12 kyr BP), the offset between the 14C and the absolute time scales was ca. 1 kyr. Varve counting and accelerator mass spectrometry (AMS) dating were used to build absolute and 14C time scales of sediments from two lakes-—Soppensee, Switzerland and Holzmaar, Germany. The resulting chronologies extend back to ca. 12.9 kyr cal BP (12.1 kyr BP) in the case of Soppensee and to ca. 13.8 kyr cal BP (12.6 kyr BP) in the Holzmaar record. They compare well with each other but differ significantly from the 14C-U/Th chronology of corals (Bard et al.1993; Edwards et al.1993).
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Intercomparison of High-Precision 14C Measurements at the University of Arizona and the Queen's University of Belfast Radiocarbon LaboratoriesHigh-precision measurements were completed concurrently at the University of Arizona and the Queen's University of Belfast on blind samples of Irish oak originally measured for the 1986 radiocarbon calibration curve. Subsequent single-year Sequoiadendron results were decadally averaged and compared with published results on decadal Douglas-fir samples. The results of these intercomparisons show that the Arizona high-precision results compare favorably with published values from the University of Washington, but show a systematic offset with published Belfast data.
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Dating of Lake and Loess SedimentsLake and loess sediments represent archives that record important information about the local, regional and global climate conditions in the past. Lake sediments consist of autochthonous particles formed by biogeochemical processes within the lake and allochthonous particles brought into the lake from the catchment area. After deposition, the stratigraphy of the sediment can be altered by chemical, physical and biological processes. Under favored conditions, the sediment shows individual annual layers (varves), which can be used to date the sediment. Other dating methods are based on radioactive decay (14C, 210Pb) or on time markers such as tephra layers, deposits of natural catastrophes, e.g., floods, or radioactivity, e.g., emissions from a nuclear power plant.
