This project tests the hypothesis that the Langobard migration into the Roman/Byzantine Veneto (northeastern Italy) resulted in significant dietary changes from Late Antiquity (4-5th centuries AD) to the Early Medieval period (6-8th centuries AD). At the end of the Great Germanic Migrations in AD 568, Langobards from Pannonia entered and occupied two-thirds of the Italian peninsula. It is unclear how large these migrations were, as historical documents exaggerate mass movements; however, conservative estimates suggest they made up 8% of the areas they occupied. The degree to which the Langobards influenced economic change and subsistence in this area is poorly understood. Therefore, the goal of this research is to use stable isotope analyses on human remains in conjunction with historical and archaeological data to understand how the migration of the Langobards influenced the population structure and political economy (diet) in the Veneto. A total of 149 individual bone samples from seven sites spanning the 4-8th centuries AD from the Veneto underwent stable carbon and nitrogen isotope analysis. In addition, 60 premolars were sampled for stable carbon, nitrogen, and oxygen isotope analysis to assess migration and dietary changes. Previous paleodietary analyses suggest that the traditional Roman diet consisted of C3 terrestrial plants, such as wheat and barley, and domesticated animals with some contributions from fish. The Langobards consumed a mix of C3 and C4 (millet and sorghum) terrestrial plants and animals. C4 plants such as millet were often considered a low socioeconomic status food source during the Roman Empire. The results indicate that migrating Langobards are not present in the cemetery samples; however, migrating Roman/Byzantines are. This suggests a migration inland from the Byzantine occupied coast for better economic prospects. Byzantine occupied areas in Italy experienced heavy taxations, while the Langobards reduced this burden on the location populations. The dietary analyses show significant differences in diet between local and non-local individuals, with non-local individuals consuming more C3 energy sources (wheat) earlier in life. In terms of overall diet in the Veneto, there appears to be an increase in millet consumption from Late Antiquity to the Early Medieval period. There are no significant differences in socioeconomic status or sex, suggesting that millet became standardized in the Veneto, reflecting a sociocultural change in dietary practices. This research is significant because it fills a geographical and chronological gap in Italian history, during a period of significant migration and economic change.

Calcium stable isotope ratios are a relatively new tool that biogeochemists can use to investigate the biogeochemical cycle of calcium in terrestrial ecosystems, having seen widespread application only in the past 15 years. To advance the application of calcium isotopes in biogeoscience research, I conducted three investigations focused on interpreting calcium isotope ratios in streamwater and in the cation exchange pool of forest soils. In the first study, we observe a shift toward lower 44Ca/40Ca ratios in streamwater draining a New Hampshire watershed after an experimental clearcutting event. Isotope ratio measurements of ecosystem calcium pools indicate that enhanced leaching of the soil exchangeable pool produced the observed shift in 44Ca/40Ca ratios. A trend towards decreased 44Ca/40Ca ratios in soils in the years following the harvesting indicates that calcium leached from the soil exchangeable reservoir was likely replaced by calcium released by the decay of belowground biomass, maintaining pre-harvest levels of exchangeable calcium even in the face of a significant ecosystem disturbance. In a second study, we observed significant differences in the 44Ca/40Ca of the soil exchange pool between two neighboring tropical watersheds, although 44Ca/40Ca of calcium inputs (bedrock and atmospheric deposition) at the two sites were indistinguishable. Further, both sites had higher 44Ca/40Ca ratios compared with external inputs, a relatively rare observation globally. We propose that hurricane disturbance best explains the high 44Ca/40Ca at each site, and that the difference in 44Ca/40Ca between the two sites can be accounted for by the magnitude of disturbance at each site. Finally, a synthesis of our new data with previously published results shows that globally, soil exchangeable 44Ca/40Ca ratios can be higher, lower or equal to external inputs. Modeling work indicates that in addition to isotopic fractionation, the balance in fluxes between vegetation and soil is critical in determining how soil exchangeable 44Ca/40Ca ratios vary relative to external inputs. When plant uptake and return to the soil are equal, soil and external inputs 44Ca/40Ca are equal, while high soil 44Ca/40Ca ratios develop when uptake exceeds return. Soil develops low 44Ca/40Ca when biomass obtains calcium from sources other than the exchangeable reservoir.

<p> The use of high flux research reactors, such as the High Flux Isotope Reactor (HFIR), to produce a wide variety of both industrial and medical isotopes has been well documented and proven to be economically feasible. However, due to the lack of access to these high flux facilities by most countries, isotope production methods utilizing reactors with low to moderate flux levels are needed, especially for short lived medical isotopes whose production must be relatively close to the location where they will be administered. In recent years medical isotopes that can both be used for treatment and diagnostic uses have become of great interest. One of the most popular of these theragnostic radionuclides is lutetium-177. Production of high-grade Lu-177 can be achieved in both high and low flux reactors through two different production methods. The current work looks to determine the feasibility of producing Lu-177 via the indirect route, using the relatively low flux of PUR-1. This will be accomplished through the use of high-fidelity models and simulations to predict the resulting production rates of the desired products. The results of these models and simulations will then be compared to the results obtained from the experimental irradiation of various samples of ytterbium oxide in PUR-1. Many studies have successfully produced Lu-177 using moderate and high flux reactors and several papers have studied the predicted production rate for low to moderate flux reactors by using the reported thermal flux of various research reactors and the reported cross-section values for ytterbium. A Monte Carlo based model of PUR-1 will be developed to determine the radiative capture reaction rates for the ytterbium targets across all neutron energies. This model in conjunction with a simplified MATLAB model, to solve the series of partial differential equations describing the production and decay of each product isotope, will be used to predict isotope production rates and will be compared to experimentally obtained results. </p>

The Mammoth Site in Hot Springs, South Dakota preserves a unique death assemblage of sub-adult and adult male Columbian mammoths (Mammuthus columbi). Extensive work on the site has led to a detailed understanding of the taphonomy of the assemblage; yet the life histories and ecology of these mammoths remain relatively unknown. Tooth enamel from four Mammoth Site mammoth individuals were bulk sampled with one of the individuals (MSL 742) also serially micro-sampled for 𝛿13C, 𝛿18O, and 87Sr/86Sr. Isotopic results indicate that MSL 742 remained within the southern and western Black Hills year-round with no consistent migration patterns. 𝛿13C and 𝛿18O values contain minimal fluctuations, suggesting drinking water and forage was sourced from the local hot springs and surrounding landscape. This study suggests the high level of sloped landscapes in the region may have resulted in a “bull”-only region, explaining the absence of females and juvenile mammoths at the site.

The Late Neogene represents warm Earth conditions immediately prior to the development of extensive northern hemisphere glaciation, and this period in Earth history may therefore provide the best available analog for the projected outcome of continued global warming. There are few interior continental sites of Late Neogene age from the eastern half of North America and subsequently very little is known about the conditions characterizing climate. The Early Pliocene (~ 5 Ma) Pipe Creek Sinkhole (PCS) includes the sediment fill of a complex karst environment that developed in north-central Indiana, USA (Lat. 40° 27′ 25.4″, Long. 85° 47′ 37.2″). The site includes more than 3 m of high-chroma, red-colored silty-clay sediment interpreted to be terra rossa. The terra rossa δ13C values average - 20 ± 0.7‰ PDB and are interpreted to represent sediment deposited in a closed cave system under high summer temperatures and with well-drained soils. An in-situ paleosol at the top of the terra rossa represents a transition from a closed cave to an open environment that eventually flooded, thereby becoming a small pond. δ13C values from lacustrine sediments with organic matter derived dominantly from algae average - 20.6‰ and suggest the pond was stagnant and enriched with bicarbonate from the underlying limestones or via aquifers. Pond sediments include abundant vertebrate fossils, which are broadly consistent with those inhabiting an open ecosystem such as a savannah or parkland. However, the PCS pollen includes low taxonomic diversity that is dominated by pine with some hickory and flowering plants, but no grass pollen. We propose two hypotheses to explain the PCS stratigraphic record: (1) The pollen assemblage may represent a local pine dominated ecosystem associated with the pond paleoenvironment, such as a riparian community, and that the greater landscape was drier and open; (2) Alternatively, the climate may have became wetter raising the elevation of the groundwater table and initiating the formation of the pond. Then in response to the wetter conditions an early succession forest ecosystem developed.

Hydrothermal systems on active volcanoes can be studied through characterization of the emitted fluids and surface discharges using major element and isotopic compositions of fumaroles and thermal springs within the volcanic area. This thesis aims at understanding the geochemistry of the existing hydrothermal systems of Kanlaon, Biliran and Bulusan volcanoes in the Philippines and the contribution of magma degassing in the formation of fluids circulating within the hydrothermal system. This study also aims at improving the geochemical monitoring program of PHIVOLCS by suggesting parameters to use in evaluating the volcano’s activity and their evolution that may lead to volcanic unrest.Kanlaon volcano’s extensive hydrothermal system evolved into two distinct hydrothermal systems independent of each other. A mature hydrothermal system represented by Pataan thermal area is characterized by neutral Na + K chloride (bicarbonate) fluids and an immature system, represented by Hagdan is characterized by the presence of acid-sulfate waters. Chemical and isotopic analyses were performed on thermals waters to classify the samples that are linked to the existence of these two hydrothermal systems. Using Cl-SO4-HCO3 relative abundances, Kanlaon’s thermal waters are classified as acid sulfate, acid sulfate-chloride, neutral chloride, and neutral bicarbonate waters. The linear trend formed by Na + K and Cl of Pataan and Mambucal samples can be explained by groundwater/meteoric dilution. This is consistent with the light sulfur isotopic signatures between δ34S = -3.4 ‰ and +1.2 ‰ of the mature hydrothermal system. This implies that the origin of sulfur is linked to the surficial oxidation of H2S. In contrast, the immature hydrothermal system shows significantly heavier sulfur isotopic composition (δ34S = +8.2 ‰), which indicates that sulfur may have originated from the disproportionation of magmatic SO2 or from the fractionation between hydrothermal sulfate and sulfide (SO42-/H2S) pairs that have achieved isotopic equilibrium.On Biliran Volcano, the area of Vulcan thermal grounds exhibits the greatest thermal activity. Thermal waters of Biliran are classified into 6 types based on their geochemistry and location on the ground. Location 1 is composed of summit springs and location 2-6 are springs found along the periphery of the volcano with varying distances from the summit springs. Immature waters are discharging from the springs located at the summit. These are the acid sulfate-chloride waters. The high concentration of SO42- and Cl- is a clear indication of the presence of magmatic HCl, H2S, and SO2. The high δ34S (+14.7 ‰ to +26.6 ‰) values suggest that these fluids were formed from the disproportionation of magmatic SO2. The acidity of the summit springs is coming from the HCl which is a contribution from the degassed magma at depth. Mature neutral (SO42- - HCO3-) Cl springs are found away from the summit moving towards the margins of the neutralization zone. Neutral Cl fluids evolved from progressive neutralization of previously acidic fluid by water-rock interaction that migrated laterally and emerged as bicarbonate waters in the periphery of the volcano. Mt. Bulusan hydrothermal system is complex and tends to show the signature of a deep neutral Cl fluid. Based on Cl and SO42-, there are two groups of springs and these are found in two different locations. Type I springs are located on Mt. Bulusan close to the crater. The predominance of HCO3- and SO42- can be associated with shallow interactions and processes (i.e. boiling of hydrothermal fluids producing steam) that modify the fluid of meteoric in origin. Major gases such as CO2(g) and H2S(g) are incorporated in the groundwater via condensation. Type II springs are located on the periphery of the volcano, far from the location of Type I springs. These springs are characterized by the presence of Cl- and HCO3- ions at concentration levels greater than SO42- concentrations. The low solubility of CO2 allows the gas phase to be transported over long distances and converted to HCO3-. The origin of Type II fluids can either be through adsorption of CO2-bearing gases, or condensation of CO2-rich geothermal steam. The proximity of one Type II spring to sea level can have a bearing on the origin of Cl- in the fluids, but the fact that all Cl- composition of these springs are quite uniform, this means that the chloride must have come from one source and that it is highly unlikely to receive any contribution from seawater. This is also supported by the Cl/B and Cl/Li composition of Type II springs. Mt. Bulusan does not have ‘pure’ neutral chloride water signature but rather a mixture of neutral Cl waters and HCO3-rich waters. / Le travail de thèse est consacré à l’étude de systèmes hydrothermaux de volcans actifs qui ont été caractérisés grâce à l’étude géochimique (éléments majeurs et composition isotopique) des fluides hydrothermaux émis en surface de zones volcaniques. L’objectif principal de la thèse est l’interprétation de la composition géochimique des fluides hydrothermaux présents dans 3 systèmes actifs :les volcans Kanlaon, Biliran et Bulusan aux Philippines. Cette étude a également pour but d’améliorer le programme de monitoring de l’activité volcanique du PHIVOLCS (Philippine Institute of Volcanology and Seismology) en proposant des paramètres géochimiques utiles à l’évaluation de l’état d’activité d’un volcan et qui peuvent également fournir de signaux précurseurs d’une activité éruptive. Dans le cas du Volcan Kanlaon, la présence de deux systèmes hydrothermaux distincts a été mise en évidence grâce à l’analyse géochimique et isotopique des eaux thermales présentes dans le massif volcanique. Un système hydrothermal « mature » caractérisé par des fluides neutres chlorures (Na+K/Cl) est présent sous la zone hydrothermale de Pataan. Le deuxième système hydrothermal, situé dans la zone de Hagdan, présente au contraire des propriétés d’un système « immature » dominé par des fluides de type acide sulfate. En comparant les abondances relatives en Cl-SO4-HCO3, différents types de composition de sources thermales sont observées :acide sulfate, acide sulfate-chlorure, neutre chlorure et neutre bicarbonate. La corrélation linéaire qui existe entre les alcalins (Na+K) et les chlorures dans les échantillons de Pataan et de Mambucal suggère une origine identique et un processus de simple dilution par des eaux d’origine météoritique. D’autre part, la signature isotopique des sulfates à Mambucal avec une gamme de valeurs de δ34S entre -3.4 ‰ et +1.2 ‰ est typique de l’oxydation à proximité de la surface de l’H2S et tend à confirmer le caractère « mature » du système hydrothermal. La signature isotopique contrastée des sulfates de Hagdan avec un δ34S = +8.2 ‰ suggère que l’origine du soufre dans ce système « immature » pourrait être liée soit à la disproportionation du SO2 d’origine magmatique soit résulté d’un fractionnement isotopique à l’équilibre au niveau du sytème hydrothermal de la paire SO42-/H2S.Dans le cas du volcan Biliran, l’activité hydrothermal principale est située dans la zone sommitale de Vulcan. 6 types de composition géochimique différents ont été mis en évidence. Dans la zone sommitale de l’édifice volcanique, des eaux « immatures » de type acide sulfate-chlorure ont été identifiées. Les concentrations élevées en SO42- et Cl- suggèrent une contribution magmatique et la présence de HCl, H2S and SO2 émis par le dégazage d’une intrusion magmatique superficielle. Les valeurs élevées en δ34S (+14.7 ‰ à +26.6 ‰) suggèrent clairement que les sulfates proviennent de la réaction de disproportionation de SO2 d’origine magmatique. D’autre part, les valeurs d’acidité de ces sources sont nettement corrélées à l’abondance des chlorures et donc à la contribution d’HCl gazeux d’origine magmatique. En périphérie de la zone sommitale, les sources chaudes sont caractérisées par des eaux « matures » de type (SO42- - HCO3-) + Cl- dont l’acidité est largement neutralisée. Des fluides neutre chlorures provenant de la neutralisation progressive de fluides acides par interaction avec les roches encaissantes et enrichis en bicarbonates sont également présents dans les zones périphériques du volcan Biliran.Le système hydrothermal du Mt. Bulusan est complexe mais tend à révéler la présence d’un réservoir profond de composition neutre chlorure. Deux groupes de sources chaudes distincts sont présents dans deux zones distinctes de l’édifice volcanique. Sur base des compositions en Cl et SO42-, deux groupes distincts de sources chaudes ont été observées. Le type I, localisé à proximité du cratère du Bulusan, est caractérisé par la prédominance de HCO3- et SO42- et pourrait résulter de la condensation et dissolution de vapeurs (H20(g), CO2(g) et H2S(g)) essentiellement hydrothermales par des eaux superficielles d’origine météoritique. Le type II, observé beaucoup plus en périphérie de l’édifice volcanique, se distingue par l’abondance des ions Cl- et HCO3- qui dominent largement les concentrations en SO42-. L’origine des sources chaudes de type II est liée à la condensation/dissolution de vapeurs hydrothermales riches en gaz carbonique, le CO2 ayant, en raison de sa plus faible réactivité chimique, la faculté de diffuser latéralement sur de longue distance au sein d’un édifice volcanique. La proximité de certaines sources de type II avec la mer tend à suggérer une origine marine pour le chlore. Cependant, le même type II est également observé à grande distance de la mer où une contribution marine est difficilement envisageable. D’autre part, les compositions relatives en Cl/B and Cl/Li des sources de type II ne semblent pas compatibles avec une origine marine. Aucune composition de fluide « mature » de type neutre chlorure n’a été observée, l’origine des fluides de type II pourrait cependant résulter d’un mélange entre des eaux enrichies en HCO3- et des eaux neutres chlorures. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Lakes have historically been overlooked as important nutrient processors within their watersheds. In general ecologists have focused on streams as zones of uptake and transformation, while viewing lakes as simple nutrient traps. However, recent research has highlighted the large influence that lakes may have on water chemistry within their watersheds. Within the field of limnology, researchers have traditionally focused on the pelagic zone for in-lake production. Further research in shallow lakes has highlighted the role benthic production within the littoral zone plays in the lake ecosystem. The greater influence of lakes is highlighted when comparing watersheds containing lakes with watersheds composed of solely stream channels. To assess the influence that lakes have on water chemistry and nutrient transport, both field and modeling analyses were performed for Bull Trout Lake, Idaho. In 2008 a large field sampling effort was conducted along with a 15N tracer experiment to characterize the limnology of Bull Trout Lake (Idaho) and nitrogen uptake and transport through the lake. Following the termination of the field season a multi-lake ecosystem model was developed with the use of a one-dimensional lake water quality model. Results from both experiments demonstrated the role of Bull Trout Lake as a nutrient processor and source within its watershed and further suggested the added influence additional lakes might have on water chemistry. The outcomes of the tracer study indicated that pelagic primary producers have the first opportunity to assimilate nitrogen delivered by the inflow stream; however, nutrients incorporated into plants within the littoral zone are held on to longer. Further the tracer experiment demonstrated the small role that large organisms have in ecosystem nutrient dynamics. The multi-lake model demonstrated the effect of BTL as a nutrient source within the watershed and indicated that although multiple lakes in sequence may have additive effects, most of this influence is expressed in the first two lakes of a series. Our research provides examples of valuable tools in limnological research. While whole-lake tracer studies have rarely been performed, they are extremely effective in understanding ecosystems. Additionally, even though lake models may be simplifications of natural systems, they can provide an efficient means of understanding lake functioning and testing hypotheses.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18086号 / 理博第3964号 / 新制||理||1571(附属図書館) / 30944 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 平田 岳史, 教授 田上 高広, 准教授 三宅 亮 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18235号 / 工博第3827号 / 新制||工||1586(附属図書館) / 31093 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 北川 進, 教授 濵地 格, 教授 宮原 稔 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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