Dendrochronological investigations on subfossil European ash (Fraxinus excelsior L.) wood found in two bogs of Western Lithuania are presented. Radiocarbon dating has revealed that Fraxinus grew in the Middle and Late Holocene, from approximately 4700 BC to 1500 BC. It is proposed that the growth of Fraxinus at these bogs was limited by differing hydrological regimes. Rising soil water levels induced a long decline in radial growth followed by a sharp reduction (up to 51%) in ring widths before the trees died. Until now, forest history in Lithuania was mostly based on results from palynological studies. This research demonstrates the potential of using dendrochronology to extend the distribution record of Fraxinus in the Baltic region during different periods of the Holocene.

In order to determine the timing of Antarctic ice sheet retreat and advance during the Late Quaternary, various tools are used to measure the age of marginal marine sediments. Carbonate 14C dating is a well-established approach, but requires foraminiferal microfossils, shells or other carbonate materials that are rare in most Antarctic regions, and may also suffer from vital effects, which can result in variability of up to 500 years in living organisms. Bulk acid insoluble organic (AIO) 14C dates are frequently as an alternative, but this approach works best where high productivity and sedimentation rates reign, and not too well in condensed sequences where high proportions of detritus are present. Compound specific dating methods have also been employed, but these may still yield an average age from a mixture of components and require very large sample sizes. Alternate methods of applying a chronology have also been used, such as magnetic intensity dating, or regional correlation with well-dated cores, but these may not always provide accurate and precise dates. Here I present work, some published with co-authors, of progressive improvements of Ramped PyrOx 14C dating, which utilizes the thermochemical degradation of components within a bulk AIO sediment sample. This dissertation focuses on the study, improvement and application of advanced Ramped PyrOx techniques. These improvements include novel techniques, such as compositing and isotope dilution that I use to date sediments where the proportion of contemporaneously deposited carbon is very small relative to other detrital components, and maximize the accuracy of resulting dates while minimizing costs in precision from utilizing ultra-small fractions of the bulk sample. Ramped PyrOx 14C dating techniques allows us to generate chronologies for cores that would otherwise go undated. Furthermore, these techniques can be used to push the limits of radiocarbon dating not only to regions where accurate core chronologies have been difficult to come by, but also further back in time, into marine sediment horizons deposited at or before the last glacial maximum (LGM), where highly detrital material has precluded radiocarbon dating in the past. Wider use of these techniques can enable more coordinated a priori coring efforts to constrain regional glacial responses to rapid warming.

The major work involved is the development of a practical and reliable radiocarbon dating laboratory at Ball State University. The method involved in determining the age of an organic sample, such as wood, peat, bone, or shell, is a carbon to benzene conversion procedure, followed by a liquid scintillation counting technique. The procedure involves producing; lithium carbide at 9000 C from our carbon sample, and then adding distilled water at room temperature to generate acetylene gas. Using a vanadium pentoxide on alumina catalyst, the acetylene is trimerized to benzene. The benzene is used in the liquid scintillation counter to determine the radiocarbon content. The age of a sample is then calculated from the ratio of carbon-14 to carbon-12, as found through the counting technique.Ball State UniversityMuncie, IN 47306

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 2004 (平成16)年度

第22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21(2009)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

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.

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.

This dissertation examines Moche (A.D. 300-900) sociopolitical organization in northern Peru at the previously unexplored site of Licapa II, a mid-sized ceremonial center in the Chicama Valley. Moche’s distinct archaeological signatures, chiefly, ceramics and architecture, have long been seen as emblematic of an ethnic and political reality and defined as evidence for the first South American state although recent scholarship has begun to view Moche as a more complex mosaic of interacting settlements across a landscape. My research at Licapa II is the first study of a site of its size and kind, thus constituting a novel contribution to the paradigm shift in Moche research. My excavations, surface collections, and geophysical surveys contributed to understanding the nature of the site and the activities performed there. Licapa II consists of two pyramids (huacas), a canal, and other buildings. I show that the two major structures, Huaca A and Huaca B, are characterized by different material culture, are different in form, and date to different time periods. Huaca A has local ceramics and was mainly used before A.D. 600. Huaca B has Moche IV and V style ceramics and was in use after A.D. 600. Based on my evaluation of radiocarbon dates, the changes in buildings and ceramics seen at Licapa II around A.D. 600 also occurred throughout the Moche world and included the adoption of Moche IV ceramics and soon after, in some places, Moche V. I also show that the Moche V style likely originated in the northern Chicama Valley and spread from there circa A.D. 650. I also argue that political organization in Moche times may have been similar to colonial era organization, based on nested moieties organized around the irrigation system. Overall, in this dissertation I demonstrate that Licapa II was an independent center intimately connected to a dynamic landscape of interconnected nodes in an ever- changing and complex network of sites. Simplistic models based on the concept of large Moche states thus should be discarded. / Anthropology