Browsing Radiocarbon, Volume 31, Number 2 (1989) by Title
Now showing items 18-26 of 26
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Price ListDepartment of Geosciences, The University of Arizona, 1989-01-01
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Problems Associated with the Use of Coal as a Source of 14C-Free Background MaterialMany 14C dating laboratories have established that coal samples exhibit a finite 14C age, apparently caused by contamination of the specimens before any laboratory preparation is undertaken. In this work, the possibility that the contamination is due to microbial and fungal activity in the coal substrate is considered and some suggestions are made for alternative sources of background test materials for 14C dating laboratories. Initial results indicate that geologically formed graphites contain little 14C and are likely to be good background test materials, especially in 14C AMS laboratories.
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Proceedings of the 13th International Radiocarbon ConferenceDepartment of Geosciences, The University of Arizona, 1989-01-01
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Radiocarbon, Volume 31, Number 2 (1989)Department of Geosciences, The University of Arizona, 1989-01-01
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Temporal 10Be and 14C Variations: A Tool for Paleomagnetic ResearchTemporal variations of cosmogenic radionuclide atmospheric concentrations can be caused by such global phenomena as solar activity and geomagnetic field changes as well as atmospheric circulation processes. These causes can be distinguished by the comparison of several isotope records corresponding to the same time period. We discuss a possibility for reconstructing the geomagnetic moment during the last 30,000 years from the comparison of 10Be and 14C concentrations in terrestrial archives. The results agree with conventional paleomagnetic data and promise to enrich our knowledge of geomagnetic field variations and reversals.
