We use cosmogenic 10Be analysis of fluvial sediments and bedrock to estimate erosion rates (103 – 106 year timescale) and to infer the distribution of post-orogenic geomorphic processes in the Blue Ridge Province in and around Shenandoah National Park, VA. Our sampling plan was designed to investigate relationships between erosion rate, lithology, slope, and basin area. Fifty-nine samples were collected from a variety of basin sizes (<1 – 3351 km2) and average basin slopes (7 - 26°) in each of four different lithologies that crop out in the Park: granite, metabasalt, quartzite, and siliciclastic rocks. The samples include bedrock (n = 5), fluvial sediment from single-lithology basins (n = 43), and fluvial sediment from multilithology basins (n = 11): two of these samples are from rivers draining streams exiting the eastern and western slopes of the Park (Rappahannock and Shenandoah Rivers). Inferred erosion rates for all lithologies for fluvial samples range from 3.8 to 24 m/My. The mean erosion rate for single-lithology basins in the Park is 11.6 ± 4.8 m/My. Singlelithology erosion rates ranges for fluvial samples are: granite (basin size = ~0.4-40 km2 and slope = 11-23°), 7.9–22 m/My; metabasalt (basin size = ~1-25 km2 and slope = 11-19°), 4.8–24 m/My; quartzite (basin size = ~0.1-9 km2 and slope = 12-23°), 4.7–17 m/My; and siliciclastic rocks (basin size = ~0.3-13 km2 and slope = 18-26°), 6.2–17 m/My. The mean erosion rate for multilithology basins (basin size = ~1-3351 km2 and slope = 7-22°) is 10.2 m/My, and individually for the Shenandoah River 7.3 m/My and the Rappahannock River 13.8 m/My. Bedrock erosion rates range from 2.4-13 m/My across all lithologies, with a mean erosion rate of 7.9 ± 5.0 m/My. Grain-size specific 10Be analysis of four samples showed no consistent trend of concentration with grain size. These data support Hack’s dynamic equilibrium model. Slope and erosion rate are not well correlated, and mean erosion rates are similar for different lithologies. Cosmogenicallydetermined erosion rates in Shenandoah Park are similar to or lower than those reported elsewhere in the Appalachians including those of Matmon and others (2003), 25 to 30 m/My for metaclastic rocks in the steep Great Smoky Mountains, Reuter and others (2004), 4 – 54 m/My in Susquehanna River basin for shale, sandstone, and schist, and Sullivan and others (2006), 6-38 m/My in the micaceous schist and gneiss of the Blue Ridge Escarpment. Cosmogenic erosion rates (integration over 104 yrs) in the Blue Ridge province of Shenandoah National Park are consistent with long-term unroofing rates (integration over 107 yrs) estimated from U-Th/He measurements (11-18 m/My) in samples collected near the Blue Ridge Escarpment by Spotila and others (2004), and fission tracks (20 m/My) in the Appalachians by Naeser and others (2005). The consistency of denudation rates integrated over very different periods of time suggests steady erosion most likely in balance with, and driving isostatic uplift of rock.

The main objective of this dissertation is to improve the knowledge of glacial chronology and paleoclimate of Turkey during the Late Quaternary. The 36Cl cosmogenic exposure ages of moraines show that Last Glacial Maximum (LGM) glaciers were the most extensive ones in Turkey in the last 22 ka (ka=thousands years), and they were closely correlated with the global LGM chron (between 19&plusmn;23 ka). LGM glaciers started retreating 21.3&plusmn;0.9 ka (1&sigma;) ago on Mount Erciyes, central Turkey, and 20.4&plusmn;1.3 ka ago on Mount Sandiras, southwest Turkey. Glaciers readvanced and retreated by 14.6&plusmn;1.2 ka ago (Late Glacial) on Mount Erciyes and 16.2&plusmn;0.5 ka ago on Mount Sandiras. Large Early Holocene glaciers were active in Aladaglar, south-central Turkey, where they culminated at 10.2&plusmn;0.2 ka and retreated by 8.6&plusmn;0.3 ka, and on Mount Erciyes, where they retreated by 9.3&plusmn;0.5 ka. The latest glacial advance took place 3.8&plusmn;0.4 ka ago on Mount Erciyes. Using glacier modeling together with paleoclimate proxy data from the region, I reconstructed the paleoclimate at these four discrete times. The results show that LGM climate was 8-11oC colder than today (obtained from paleotemperature proxies) and wetter (up to 2 times) on the southwestern mountains, drier (by ~60%) on the northeastern ones and approximately the same as today in the interior regions. The intense LGM precipitation over the mountains along the northern Mediterranean coast was produced by unstable atmospheric conditions due to the anomalously steep vertical temperature gradients on the Eastern Mediterranean Sea. In contrast, drier conditions along the southern Black Sea coast were produced by the partially ceased moisture take-up from the cold or frozen Black Sea and prevailing periglacial conditions due to the cold air carried from northern hemisphere's ice sheets. Relatively warmer and moister air from the south and overlying cold and dry air pooled over the northern and interior uplands created a boundary between the wet and dry LGM climates somewhere on the Anatolian Plateau. The analysis of Late Glacial advances suggests that the climate was colder by 4.5-6.4oC based on up to 1.5 times wetter conditions. The Early Holocene was 2.1oC to 4.9oC colder on Mount Erciyes and up to 9oC colder on Aladaglar, based on twice as wet as today's conditions. The Late Holocene was 2.4-3oC colder than today and the precipitation amounts approached the modern levels. Glaciers present on Turkish mountains today are retreating at accelerating rates and historical observations of the retreat are consistent with the behavior of other glaciers around the world.

The Daya Bay reactor neutrino experiment is a high sensitivity experiment designed to determine the last unknown neutrino mixing angle $theta_{13}$ by measuring disappearance of reactor antineutrinos emitted from six 2.9 $GW_{th}$ reactors at the Daya Bay Nuclear Power Station. There are eight identical Gd-loaded liquid scintillator detectors deployed in two near (flux-weighted baseline 512 $m$ and 561 $m$) and one far (1579 $m$) underground experimental halls to detect the inverse beta decay interaction. This dissertation describes the Daya Bay Experiment and individual contributions to this experiment. Chapter 1 reviews the history of the neutrino and the neutrino oscillation phenomena. The reactor based neutrino experiments in different times are described in this chapter in detail. It presents the motivation of the Daya Bay Experiment. In Chapter 2, the neutrino detection method and the $theta_{13}$ relative measurement method are introduced. This chapter focuses on the design of the Daya Bay Experiment, including antineutrino detector, calibration system, muon veto system and muon tagging system. Chapter 3 shows the design, development, construction, and assembly of Muon Pool PMT calibration system, and presents an algorithm of calculating the muon pool PMT timing offset values. Chapter 4 focuses on the manufacture, installation and commissioning of RPC HV system. Chapter 5 presents the analyses of the radioactive isotopes induced by comic muons. The Daya Bay detector energy response model is also described in detail. The relative rate analysis results exclude a zero value from $sin^22theta_{13}$ with a significance of 7.7 standard deviation using 139 days of data, 28909 (205308) antineutrino candidates which were recorded at the far hall (near halls) and shows $sin^22theta_{13} = 0.089pm0.011$ in a three-neutrino framework. A combined analysis of the $overline nu_e$ rates and energy spectra based on the detector energy response model improved measurement of the mixing angle $sin^22theta_{13} = 0.090^{+0.008}_{-0.009}$ by using 217 days of data, 41589 (203809 and 92912) antineutrino candidates were detected in the far hall (near halls). Also the first direct measurement of the $overline nu_e$ mass-squared difference $|Delta m^2_{ee}|= (2.59^{+0.19}_{-0.20})times10^{-3}$ $eV^2$. It is consistent with $|Delta m^2_{mumu}|$ measured by muon neutrino disappearance, supporting the three-flavor oscillation model. / Ph. D.

Understanding the link between the Sun and climate is vital in the current incidence of global climate change, and 10Be in natural archives constitutes an excellent tracer for this purpose. As cosmic rays enter the atmosphere, cosmogenic isotopes like 10Be and 14C are formed. Variations in solar activity modulate the amount of incoming cosmic rays, and thereby cosmogenic isotope production. Atmospherically produced 10Be enters natural archives such as sediments and glaciers by wet and dry deposition within about a year of production. 10Be from natural archives therefore provides information on past solar activity, and because these archives also contain climate information, solar activity and climate can be linked. One remaining question is to what degree 10Be in natural archives reflects production, and to what extent the local and regional environment overprints the production signal. To explore this, 10Be was measured at annual resolution over the last 600 years in a Greenland ice core. Measurement potentials for these samples benefited from the development of a new laboratory method of co-precipitating 10Be with niobium. To diversify geographic location and archive media type, a pioneer study of measuring 10Be with annual resolution in varved lake sediments from Finland was conducted, with samples from the entire 20th century. Pathways of 10Be into lake sediments are more complex than into glacial ice, inferring that contemporary atmospheric conditions may not be recorded. Here, it is shown for the first time that tracing the 11-year solar cycle through lake sediment 10Be variations is possible. Results also show that on an annual basis, 10Be deposition in ice and sediment archives is affected by local environmental conditions. On a slightly longer timescale, however, diverse 10Be records exhibit similar trends and a negative correlation with solar activity. Cyclic variability of 10Be deposition persisted throughout past grand solar minima, when little or no sunspot activity was recorded. 10Be levels indicate that although solar activity has been high during the 20th century, levels are not unprecedented in the investigated 600 years. Aerosol 10Be/7Be values indicate possible influence of stratosphere-troposphere exchange on isotope abundance and the production signal.

abstract: For this dissertation, three separate papers explore the study areas of the western Grand Canyon, the Grand Staircase (as related to Grand Canyon) and Desolation Canyon on the Green River in Utah. In western Grand Canyon, I use comparative geomorphology between the Grand Canyon and the Grand Wash Cliffs (GWC). We propose the onset of erosion of the GWC is caused by slip on the Grand Wash Fault that formed between 18 and 12 million years ago. Hillslope angle and channel steepness are higher in Grand Canyon than along the Grand Wash Cliffs despite similar rock types, climate and base level fall magnitude. These experimental controls allow inference that the Grand Canyon is younger and eroding at a faster rate than the Grand Wash Cliffs. The Grand Staircase is the headwaters of some of the streams that flow into Grand Canyon. A space-for-time substitution of erosion rates, supported by landscape simulations, implies that the Grand Canyon is the result of an increase in base level fall rate, with the older, slower base level fall rate preserved in the Grand Staircase. Our data and analyses also support a younger, ~6-million-year estimate of the age of Grand Canyon that is likely related to the integration of the Colorado River from the Colorado Plateau to the Basin and Range. Complicated cliff-band erosion and its effect on cosmogenic erosion rates are also explored, guiding interpretation of isotopic data in landscapes with stratigraphic variation in quartz and rock strength. Several hypotheses for the erosion of Desolation Canyon are tested and refuted, leaving one plausible conclusion. I infer that the Uinta Basin north of Desolation Canyon is eroding slowly and that its form represents a slow, stable base level fall rate. Downstream of Desolation Canyon, the Colorado River is inferred to have established itself in the exhumed region of Canyonlands and to have incised to near modern depths prior to the integration of the Green River and the production of relief in Desolation Canyon. Analysis of incision and erosion rates in the region suggests integration is relatively recent. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2016

Le sujet de ce travail est une analyse géomorphologique et tectonique pluri-échelle de la Provence, où des séismes historiques d'intensités majeures (VIII voire IX) ont été répertoriés durant les derniers siècles (par exemple à Lambesc, 1909). Si l'intensité des séismes historiques est relativement élevée en Provence, la région ne subit qu'une faible microsismicité, d'où la nécessité d'une approche tectonique, géomorphologique et paléosismologique pour y étudier les déformations récentes. Afin d'appréhender la morphogénèse grande longueur d'onde en Provence, nous avons évalué les taux de dénudation des massifs carbonatés de la région grâce à des mesures de concentrations en isotopes cosmogéniques 36Cl. Nous obtenons des taux de dénudation comparables entre les différents sites (de l'ordre de 20 à 60 mm/ka) et comparables aux études précédentes dans ce type de contextes, sauf pour le Grand Luberon et la montagne de Lure, qui s'érodent plus rapidement (jusqu'à 140 mm/ka). Cette approche a été appliquée à plus petite échelle sur le Petit Luberon, où nous comparons la dénudation de la surface sommitale à la dénudation moyennée sur plusieurs bassins versants de ses flancs sud et nord.Enfin, nous avons implémenté une approche pluri-disciplinaire à une échelle locale, associant cartographie haute-résolution, mesures de résistivités électriques, paléosismologie, granulométrie et datations afin d'obtenir une meilleure compréhension du comportement Quaternaire et Holocène d'un segment de faille localisé à Vinon-sur-Verdon. Notre analyse confirme de la déformation dans les 200 derniers milliers d'années sur ce contact mais démontre l'absence de déformation depuis 16000 ans. / This manuscript deals with a multi-scale geomorphological and tectonic analysis of Provence, a region where large scale historical earthquakes (intensities of VIII or even IX) have been recorded during the last centuries (e.g. in Lambesc, 1909). If the intensity of historical earthquakes is relatively high in Provence, the region undergoes a weak microseismicity, hence the need for a tectonic, geomorphologic and paleoseismologic approach to understand the recent deformations.In order to evaluate the large-scale morphogenesis in Provence, we evaluated the denudation rates of the carbonate ranges of the region by measuring 36Cl cosmogenic isotope concentrations. We obtain comparable denudation rates between different sites (in the order of 20-60 mm/ka) and comparable to previous studies in this type of contexts (e.g. Ryb et al., 2014a, b), except for the Grand Luberon and the Lure mountain, which erode more quickly (up to 140 mm/ka). This approach was applied on a smaller scale by focusing on the Petit Luberon, where we compare the denudation of the summit surface to the denudation averaged over several watersheds on its southern and northern flanks.Finally, we implemented a multi-disciplinary approach on a local scale, associating high-resolution mapping, electrical resistivity measurements, paleoseismology, granulometry, 14C and OSL dating, in order to obtain a better understanding of Quaternary and Holocene behavior of a fault segment located in Vinon-sur-Verdon. Our analysis confirms that deformation occurred in the last 200 thousand years on this contact but demonstrates the absence of deformation in the last 16000 years.

Dans cette thèse nous quantifions les interactions entre phénomènes tectoniques et magmatiques au niveau d'un rift proche de la rupture continentale: celui du Dabbahu / Manda Hararo en Afar (Ethiopie), qui a été le siège d'un épisode de rifting majeur en 2005. Nous apportons ici des contraintes temporelles sur ces interactions à l'échelle du millier à la dizaine de millier d'années, afin de mieux comprendre l'évolution des processus responsables de l'acquisition de la topographie. Pour cela nous avons produits des âges d'expositions de surfaces de coulées de laves et d'escarpement de failles par la technique des isotopes cosmogéniques. Ces datations ont été combinées à des travaux de cartographie et de géochimie (éléments majeurs et traces). Nous montrons que nord du segment est sous l'influence de la présence d'un volcan terminal qui impacte le développent de la topographie. Le milieu du segment permet d'évaluer l'impact des variations spatiales et temporelles de la localisation des réservoirs sur la topographie. Le long du segment, il apparaît que la topographie se développe quand les réservoirs magmatiques locaux ont une activité modérée à faible, alors que la topographie est inhibée lors des phases de magmatisme intense. Nos observations ont permis de monter que l'épisode de rifting de 2005 n'est pas représentatif de l'évolution globale de la morphologie du rift, et que ce type d'intrusion ne représente sans doute qu'un dixième des injections totales. Enfin, l'accrétion magmatique est soutenue à l'axe par différents réservoirs magmatiques qui semblent se relayer dans le temps, et dont la position peut varier de 15 kilomètres de part et d'autre de l'axe / In this thesis we quantify the interactions between tectonic and magmatic processes in the active Dabbahu rift segment, which experienced in 2005 a major rifting event. Here, we provide accurate constraints at this time scale by producing cosmogenic exposure ages of lavas surfaces and faults scarps, in order to decipher the morphological evolution of a rift depression, and to identify the processes that are responsible for the topography acquisition. The study is based on samples taken on two separate areas of the rift. The field areas were systematically mapped, and all lavas were chemically analysed in major and trace elements. The first studied focused the northern portion of the rift segment, where the lavas of the segment terminating volcano meets the neo-volcanic zone. This area allowed the influence of the presence of such volcanic edifice to be assessed. The second studied area is located at the middle of the segment, and covers the rift western margin up to the rift axis. The topography in this area is sensitive to the evolution in space and time of the location of the different axial magma reservoirs. Our results show that along the rift segment, topography develops during phases of low magmatic activity, and is inhibited during phases of lower magmatic activity. The 2005 appears to be an unusual event that represents about a tenth of the total intrusions necessary to build the depression. The maintaining of magmatic accretion at the axis seems to be the result of a relay between different magma reservoirs. The position of these reservoirs can vary between 0 and 15 km from both sides of the rift axis

L'expérience JUNO est une expérience basée sur un détecteur à scintillateur liquide ayant pour objectif principal de déterminer la hiérarchie de masse des neutrinos. JUNO atteindra une sensibilité de trois écarts standards en 6 ans, avec une résolution en énergie sans précédent, meilleure que 3% à 1MeV. Le détecteur central de JUNO est un détecteur à scintillateur liquide de 20 kilotonnes, construit avec une couverture de photocathode élevée (78%) et une bonne transparence. La couverture de photocathode est assurée par 18000 photomultiplicateurs de 20 pouces et 25000 de 3 pouces, ce qui permet d'atteindre un rendement d'environ 1200 photoélectrons par MeV. Malgré les 700m d'épaisseur de roche protégeant le détecteur des rayonnements cosmiques, le bruit de fond induit par les muons atmosphériques est toujours considéré comme non négligeable par rapport au signal attendu pour la détermination de la hiérarchie de masse. Pour faire face à ce bruit de fond, un détecteur appelé "Top Tracker" permet d'améliorer la détection de ces muons. Cette thèse concerne les travaux d'optimisation pour cette expérience actuellement en cours de construction, et dont les prises de données commenceront en 2021.Pour les photomultiplicateurs de 20 pouces, deux nouvelles géométries de concentrateurs de lumière sont étudiées afin de vérifier leurs performances pour augmenter le rendement photoélectronique et donc la résolution en énergie de JUNO. La distribution spatiale et le schéma de câblage des photomultiplicateurs de 3 pouces font aussi l'objet d'études pour assurer une performance optimale du système.Cette thèse aborde ensuite la conception du système de déclenchement du Top Tracker. En effet, ce détecteur doit posséder un tel système pour rejeter les signaux produits par la radioactivité naturelle dans la caverne. Les résultats montrent qu'un système à 2 niveaux doté d'algorithmes optimisés est efficace pour la suppression de ces signaux et qu'il est ainsi possible d'obtenir une efficacité de détection des muons de 93%. Une discussion sur la contribution du Top Tracker à la suppression et à la mesure du bruit de fond induit par les muons atmosphériques est également incluse. / The JUNO experiment is a multi-purpose liquid scintillator neutrino experiment with the main objective of determining the neutrino mass hierarchy (nuMH) with a significance better than 3sigma. To achieve this goal, it is crucial that JUNO has an unprecedented energy resolution of 3% at 1 MeV. Therefore, the JUNO Central Detector (CD) will be built with 20000 ton high transparency liquid scintillator and high photomultiplier tube (PMT) photocathode coverage of 78%, which is provided by 18000 20"-PMTs (LPMTs) and 25000 3"-PMTs (SPMTs). At the same time, the background induced by atmospheric muons should be vetoed by using reconstructed muon tracks. The Top Tracker (TT) is a muon tracker installed on top of the CD for precise muon tracking.This thesis details firstly the optimisation of the LPMT and the SPMT systems, which are directly related to the antineutrino calorimetry. New designs of light concentrator tailored for the JUNO LPMT are studied in order to verify their performance on increasing the JUNO photoelectron yield. By comparing different configurations, the relation between the SPMT system performance and the non-uniform distribution of the SPMT emplacements is studied, and the scheme used for cabling between SPMTs and their Under Water Boxes (UWBs) is studied to ensure a minimal performance degradation in case of UWB failure.Afterwards, this thesis reports on the design and optimisation of the TT trigger algorithms. Due to the background induced by natural radioactivity in the JUNO cavern, the TT cannot work correctly without a trigger system. The results show that a 2-level trigger with the optimised trigger algorithm is effective for the background suppression and thus a muon detection efficiency of 93% can be achieved.A discussion about the TT contribution to the suppression and the measurement of the atmospheric muon-induced background, is also included.