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" The determination of the reliability of uranium series dating of enamel, dentine, and bone "
C. R. McKinney, Jr.
M. Holdaway
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Latin Dissertation
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English
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| Record Number
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1112690
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TLpq303958284
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| Main Entry
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C. R. McKinney, Jr.
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M. Holdaway
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| Title & Author
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The determination of the reliability of uranium series dating of enamel, dentine, and bone\ C. R. McKinney, Jr.M. Holdaway
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| College
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Southern Methodist University
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| Date
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1991
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| student score
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1991
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| Degree
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Ph.D.
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| Page No
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199
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| Abstract
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This research, a detailed study of the Uranium (U) series geochemistry in fossil bones and teeth from three C dated, late Pleistocene spring sites in the central Missouri highland and a stratified Middle Paleolithic locality at Bir Tarfawi, Egypt tests the potential for U-series dating of enamel, dentine, and bone. The Missouri spring environments and the fossils in them are atypical in that they contain unusually high concentrations of U, a feature which simplified the chemical analysis and yielded precise isotope ratio measurements despite the young age of the fossil material. At Bir Tarfawi, the pluvial lake deposits contain middle Paleolithic artifacts and abundant skeletal remains. This area has low U/U activity ratios while U abundances are high. The results demonstrate that when U-series analysis is used systematically absolute dating is possible. Of the materials tested, enamel yields the most consistent results among enamel, dentine, and bone, although multiple analyses are necessary to ensure accuracy. The C and U-series methods give concordant dates for enamel from Trolinger Spring and the upper peat at Jones Spring, but at Boney Spring results are ambiguous while at Bir Tarfawi results are non-concordant. U-series dates on bone are generally younger than the C dates, whereas cementum and dentine lack any consistent pattern. U-series dating of enamel can be applied beyond the limit of C analysis, to build a refined chronology of the last 400 ka. Fission track mapping was used to analyze U concentrations and to determine the U distribution in enamel of different ages from several geochemical environments. Uranium tends to be restricted to the outer edges of the enamel in enamels that are concordant with C dates. Tooth enamel from Bir Tarfawi had greater U dispersion and the U-series dates were not concordant with other methods or the stratigraphy. When the enamel is weathered, however, the uranium content is highest in the alteration zone. The analysis of late Pleistocene and Holocene enamels to establish the period of initial U uptake from the local environment shows that absorption apparently ends between 100 and 1000 years after deposition. It is concluded that early U uptake is the primary mode of U absorption at the Missouri Spring localities and therefore dates from methods such as ESR which depend on the assumption of linear or late U uptake must be revised when the U distribution in enamel is narrowly confined to the outer edge.
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Archaeology
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Earth sciences
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Geochemistry
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Geochemistry
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Paleontology
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Social sciences
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