第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告

第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告

Plasma oxidation, an alternative to combustion, is shown to be a non-destructive method for obtaining radiocarbon dates on perishable organic artifacts. Electrically excited oxygen gently converts organic carbon to carbon dioxide. Radiocarbon measurements are then performed using accelerator mass spectrometry. Because only sub-milligram amounts of material are removed from an artifact over its exposed surface, no visible change in fragile materials has been observed, even under magnification. Materials in this study include: Third International Radiocarbon Intercomparison (TIRI) sample B (Belfast pine); Fourth International Radiocarbon Intercomparison (FIRI) optional samples; six different materials from a naturally mummified baby bundle from southwest Texas; and peyote from Shumla Caves, Texas, and Cuatro Ci??negas, Mexico. Continuing previous research in the Rowe laboratory, a primary application of plasma oxidation has been its use to date rock art at archaeological sites around the world. This dissertation includes dates for: Toca do Serrote da Bastiana, Brazil; Ignatievskaya Cave, Russia; partially buried megalithic monuments, Spain; Arnold/Tainter Cave, Wisconsin; and Little Lost River Cave No. 1, Idaho.

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 76-81).

Thesis (D. Mus. Arts)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 104-110).

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. M. Lynne Cooper. Includes bibliographical references.

Thesis (M.A.)--York University, 1999. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 69-82). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ56162

Thesis (M.A.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains v, 64 p. Vita. Includes abstract. Includes bibliographical references (p. 44-54).

In the last ten years it has become apparent that the radiocarbon dating method can significantly underestimate the age of samples > 25 ka BP because routine pre-treatment protocols may not remove sufficient contaminants. In response, new pre-treatment protocols have been proposed, and two in particular, ultrafiltration of bone collagen and ABOx-SC of charcoal, show promise. This thesis has tested whether these methods effectively remove contaminants without adding carbon in the laboratory. Subsequently it used them, alongside careful selection of humanly modified material and Bayesian statistical analysis, to test the radiocarbon-based chronology of the Iberian Middle to Upper Palaeolithic transition. Both protocols were found to effectively remove environmental contaminants, but add small amounts of laboratory-derived carbon. Using known age standards, a correction has been calculated for the ultrafiltration protocol to counter the effect of the laboratory-derived carbon. A similar correction could not be made for the ABOx-SC protocol due to uncertainties in the age of the standards and underlying chemical processes. However, the effect of such contamination did not have a significant effect on the chronologies developed for the sites examined in this thesis. 96 new radiocarbon dates have been obtained from the Iberian Middle to Upper Palaeolithic transition. A further 50 dates recovered from the literature and are regarded as reliable. The most alarming finding of this thesis is that routine pre-treatment protocols may cause dates to be underestimated by more than 10 ka ¹⁴C years. The implication of offsets of this magnitude in Iberia is significant: whereas a prolonged survival of Neanderthals south of the Ebro valley has been observed in the published dataset, this study could not replicate such ages. Preservation did not allow the arrival of anatomically modern humans to be dated in the south. However, using typological arguments and the chronology constructed for the north of the Peninsula, it is unlikely that they were present in this region before 38,080 – 36,680 cal BP (95% probability). This implies a temporal gap of at least 4,490 – 12,740 cal years, although it is unclear whether this is due to taphonomic factors or is a real period of abandonment. This pattern contrasts to northern areas of the Peninsula where the Aurignacian appears at 42,330 – 40,980 cal BP, shortly postdating the start of the Châtelperronian and end of the Mousterian. It is hoped that the chronology produced will warn against the use of radiocarbon dates produced using poor pre-treatment protocols and has laid the foundations from which a more accurate and more precise chronology can be built in the future.

The objective of this project is to apply the Optical Stimulated Luminescence (OSL) technique to date the palaeo sediment from Mu Us Desert, part of the Inner Mongolia in northern China and reconstruct the palaeo environment. Five OSL samples were collected from Dagouwan, Salawusu River Valley at Inner Mongolia by Dr S. H. Li and his team in 2009. Extraction of 150μm to 180μm silt-size feldspar from collected dune sand, lacustrine facies and fluvial facies samples and running of luminescence dating therefore to obtain the age from 50ka to 90ka. Climate proxies - magnetic susceptibility, grain size, fossil vertebrates and fossil pollens have been analyzed and it is concluded that significant climate change occurred within this period, which change from domination of warm, humid and rainy summer monsoons (before 70ka) to cold, wind, windy strengthened dry winter wind and back to warm and humid again after 55ka. / published_or_final_version / Applied Geosciences / Master / Master of Science