The COSC-1 borehole located in the Lower Seve nappe of the Central Scandinavian Caledonides is intended to study the tectonic evolution of the Paleozoic orogen. The drilling project reached a depth of 2495.8m and obtained samples from different lithologal units of mica schist, amphibolite, gneiss, and mylonitic gneisses.     To test if the samples are suitable for paleomagnetism, laboratory measurements of natural remanent magnetism are performed on sub-samples of the COSC-1 drill core in the paleomagnetic laboratory with alternating field demagnetization, IRM acquisition as well as the temperature dependence of susceptibility measurements. Important properties of the samples such as coercivity, Curie temperature, inclination, and declination are determined with the measurements.     Most of the samples carry a remanent magnetization that can be readily demagnetized with alternating field demagnetization up to 100 mT. Some of the samples may be suitable for paleomagnetism, with the major ferromagnetic mineral compositions of magnetite, hematite, and FeTi oxides. However, low coercivities and median destructive fields suggest that the magnetite-bearing samples will be prone to remagnetization, making them more challenging to use in terms of retrieving a primary magnetization originating from the Caledonian orogeny. The thermomagnetic results of some samples reflect the metamorphic conditions experienced by the rocks and the mineral assemblage changed irreversibly during step-wise heating experiments. These results can possibly be used as an indicator for the metamorphic temperature experienced by the different lithologal units. Although further measurements are needed to get a clearer understanding of the suitability of the COSC-1 sample for paleomagnetic reconstructions (including thermal demagnetization experiments), this thesis indicates that the COSC-1 rocks contain interesting paleo- and rock magnetic features that are worth further study.

No description available.

Better understanding of pyroclastic density current (PDC) dynamics is one of the key volcanological focuses, as PDCs represent one of the most life-threatening volcanic hazards. PDCs associated with explosive collapse calderas are difficult to observe and examine directly, and thus research of internal architecture of calderas and their PDC deposits is focused on extinct and partly eroded volcano-plutonic systems. Such a case is the Late-Carboniferous Altenberg-Teplice caldera in NW Bohemian Massif, which exposes a large body of ignimbrites (deposits of the PDC) called Teplice rhyolite (an intra-caldera fill). This body is well exposed on the southern flank of the Krušné hory/Erzgebirge Mts., mainly its members: Teichweg, Lugstein-Pramenáč, Vlčí kámen-Medvědí vrch and Přední Cínovec. As these ignimbrites appear macroscopically isotropic, I employed the Anisotropy of magnetic susceptibility (AMS) in order to quantify their internal structure. A total of 1232 specimens from 63 sampling stations were analyzed for the AMS, complemented by susceptibility vs. temperature variations and petrographic observations. Obtained AMS data, carried by a mixture of paramagnetic ferrosilicates and low-Ti titanomagnetite, indicate various processes recorded in ignimbrites. The relatively oldest and moderately welded Teichweg...

A radiometric survey of the zoned 21 Ma, A-type Sheeprock granite, western Utah, combined with measurements of magnetic susceptibility and field observations were analyzed using a geographic information system. The intrusion spans 25 square km and is roughly eliptical in shape with its long axis trending northwest. Concentration maps (composed of more than 500 survey stations) of eU, eTh, texture, magnetic susceptibility, color, and joint density help to constrain magmatic and post-magmatic processes related to its chemical and physical zonation. Uranium ranges from 3.9 to 26.9 ppm (mean 12.7) and thorium from 1.7 to 125.7 ppm (mean 45.5). Similarities in spatial patterns and near normal distributions of U and Th imply minimal remobilization and secondary equilibrium of U. Relatively high magnetic susceptibility (6 to 12*10^-3 SI units), low eU and eTh, and limited whole rock chemical anayses show the southeastern part of the pluton is more mafic and most likely formed as an early cumulate. Dominant textures are porphyritic with a fine-grained matrix along the northeastern margin, coarsening to a medium-grained matrix along the southwestern margin. This transition from fine to medium-grained matrix textures is believed to be a preserved solidification front that had migrated from the roof and walls inward during cooling. Late stage magma mixing is evidenced by a string of mafic enclaves along the axis of the pluton near this solidification front. eU and eTh generally increase toward the finer-grained northeastern margin of the pluton. This has been interpreted to be the primary result of fractionation of U and Th into monazite and thorite. As mafic cumulates formed along the northeastern margin residual liquids were displaced inward. This depleted the more evolved parts of the pluton in U and Th. Beryl, a distinquishing characteristic of the most evolved portions of the pluton, is concentrated in two areas along the central axis of the intrusion. The intrusion is a cumulative of three magmatic phases, the second of which crystallized from the margins inward. Joint spacing is a major factor in controlling post-magmatic processes. The pluton has a higher density of joints (10 cm apart) near the upper margins, and fewer joints (> 1 meter apart) at lower elevations. Differential cooling and magma pressures are believed to have controlled the varying joint densities. Increased alteration, oxidation, and red-staining are more prevalent in areas of higher joint density. Magnetic susceptibility is bimodal. The high mode (5.4*10^-3 SI) is on the low end of magnetite-series granites and occurs most often in the white granite. The low mode (0.07*10^-3 SI) implies significant post-magmatic oxidation and the destruction of magnetite and correlates to the red granite. Truncated chemical and textural patterns along the pluton's northwestern margin support evidence for range front normal faulting.

No description available.

No description available.

Une calibration orbitale du Valanginien et d’une partie de l’Hauterivien (Crétacé inférieur) est présentée au cours de ce travail. Celles-ci sont basées sur l’identification des cycles de l’excentricité à partir d’analyses spectrales menées sur des proxies climatiques mesurés à haute résolution sur des alternances marne/calcaire hémipélagiques.Cinq coupes de référence sont analysées dans le Bassin Vocontien (Sud-Est de la France), couvrant l’ensemble de l’étage du Valanginien. Une durée de 5,08 Ma est proposée pour cet étage à partir de l’identification du cycle de l’excentricité de 405 ka. Le cadre temporel proposé, combiné aux âges radioisotopiques disponibles, montre que la perturbation en 13C du Valanginien moyen (événement Weissert) est antérieure à la mise en place des trapps du Paraná-Etendeka. La forte expression de l’obliquité dans la partie supérieure du Valanginien pourrait refléter la mise en place de calottes polaires de faible extension.La transition Hauterivien-Barrémien de Río Argos (Sud-Est de l’Espagne) est traitée par une analyse multi-proxies (cortèges argileux et susceptibilité magnétique ou SM). Par comparaison avec les bancs calcaires, les interbancs marneux sont enrichis en kaolinite et en illite, appauvries en smectite et possèdent de fortes valeurs de SM. Cela reflète des conditions tropicales humides lors du dépôt des marnes tandis que les calcaires se déposent en climat semi-aride. Les durées des zones d’ammonite à P. ohmi et à T. hugii sont respectivement estimées à 0,78 Ma et 0,54 Ma. L’événement anoxique Faraoni a une durée comprise entre 100 et 150 ka. Par corrélation avec d’autres coupes, Río Argos apparaît être le meilleur candidat GSSP / Orbital floating time scales are proposed for the Valanginian Stage and part of the Hauterivian Stage (Early Cretaceous). These are based on the identification of the eccentricity cycles from spectral analyses performed on high-resolution climatic proxies measured on hemipelagic marl-limestone alternations. Five reference sections were analysed in the Vocontian Basin (SE France), spanning the entire Valanginian. A duration of 5,08 myr is proposed for the Valanginian Stage from the identification of the 405-kyr eccentricity cycle. The time frame proposed, combined with available radiometric ages, shows that the mid-Valanginian 13C positive excursion (namely the Weissert Event) occurs prior to the onset of the Paraná-Etendeka traps. The stronger expression of the obliquity cycles in the upper part of the Valanginian Stage may be caused by the onset of low-extension polar ice. The Hauterivian-Barremian transition of the Río Argos section (SE Spain) was studied by a multi-proxies analysis (clay minerals, magnetic susceptibility or MS). Compared to limestone beds, marl interbeds are enriched in kaolinite and illite, impoverished in smectite and show stronger MS values. This reflect tropical humid conditions during marl deposits while limestone were deposited under semi arid conditions. The durations of the P. ohmi and T. hugii ammonite zones are assessed at 0.78 myr and 0.54 myr, respectively. The duration of the Faraoni anoxic event ranges from 100 to 150 kyr. By correlation with other sections, the Río Argos section appears to be the most valuable candidate for GSSP.

L'objectif de cette thèse est la synthèse d'un matériau modèle de la dioxygénase à manganèse, une enzyme oxydant des cycles aromatiques type catéchol grâce au dioxygène. Pour ce faire, nous avons découpé notre stratégie trois étapes constituant les différents chapitres de ce manuscrit : - La synthèse et la caractérisation des complexes de manganèse(II) avec des ligands tridentates. - L'optimisation d'une synthèse de silice mésoporeuse par micro-onde. - La fonctionnalisation des matériaux et le greffage des complexes, ainsi que les tests catalytiques préliminaires.Les ligands utilisés sont des amines tertiaires avec un bras alcyne et deux coordinants type pyridine, imidazole ou carboxylate. Ces complexes ont été cristallisés et/ou caractérisés par IR, RPE, SQUID et voltampérométrie cyclique. La synthèse par micro-onde, basée sur des conditions de synthèse hydrothermale classiquenous a permis de réduire le temps de synthèse d'un jour à deux heures. La qualité de ces nouveaux matériaux a été vérifiée par IR, ATG, BET, et DRX sur poudre. Ces matériaux sont ensuite bifonctionnalisés en utilisant une méthode de pochoir moléculaire avec une fonction azoture pour le greffage du complexe via "click-chemistry" ainsi qu'une fonction pyridine ou triméthylsilyle pour créer un environnement coordinant ou non proche du métal.Ces complexes et matériaux sont actifs dans l'oxydation du catéchol. / The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2.

Cette thèse porte sur les interactions entre les déformations halocinétiques locales au sein des mini-bassins salifères et les déformations régionales compressives. L’étude s’appuie sur une analyse structurale multi-échelle détaillée d’une province à mini-bassins se développant dans le bassin d’avant pays de Sivas (Turquie). Une analyse de terrain approfondie, associée à une étude de données de subsurface, permet de proposer une révision des cartes géologiques ainsi qu’une évolution tectonosédimentaire identifiant les déformations liées à la tectonique salifère et celles liées à la propagation de la ceinture de plis et de chevauchements dans l’avant-pays. A partir de l’Eocène supérieur, le fluage del’évaporite autochtone, initié et entretenu par le chargement sédimentaire différentiel ainsi que par la déformation compressive, permet la formation d’une première génération de mini-bassins. Ces minibassins, constitués par une formation continentale Oligocène, vont être recouverts par une nappe d’évaporite allochtone accueillant une seconde génération de mini-bassins constitués de formations continentales et marines Oligo-Miocène. L’initiation du domaine de mini-bassins secondaires est caractérisée par une distribution polygonale du réseau de diapirs et de murs d’évaporites. Ces mini-bassins enregistrent localement les effets de la tectonique salifère par le développement d’une grande variété de structures halocinétiques à différentes échelles telles que les séquences halocinétiques unitaires (crochet et éventail), séquences composites (tabulaire ou fuseau) et megaflaps. Une série de modélisation analogique préliminaire amontré que ces structures peuvent se développer avec ou sans l’application d’une compression aux limites. De plus, les analogies géométriques entre les mini-bassins de Sivas et les provinces salifères connues suggèrent que la dynamique de formation de ces mini-bassins est au premier ordre contrôlée par le chargement sédimentaire différentiel, découplé partiellement de la compression régionale. Néanmoins, l’analyse du réseau de fractures et de l’endommagement matriciel souligne l’enregistrement précoce de la déformation compressive régionale lors de l’initiation des mini-bassins.L’influence du raccourcissement sur la structuration de la province à mini-bassins s’exprime de manière croissante par l’écrasement des corps salifères permettant : (i) le développement de dépocentres linéaires préférentiellement perpendiculaire à la direction de raccourcissement, (ii) l’émergence de corps allochtones d’évaporites en surface, ainsi que (iii) la rotation et translation des mini-bassins. Cette province à mini-bassins génère une discontinuité dans la propagation et l’accommodation de la déformation compressive : la déformation compressive est accommodée auniveau du réseau polygonal de murs d’évaporites formant des structures multidirectionnelles. De plus, cette concentration de la déformation par écrasement des structures salifères entraine la remobilisation des évaporites vers l’avant-pays générant alors un nouveau système salifère. / This doctoral work studies the interaction between withdrawal of minibasins and regional shortening during evolution of a foreland fold-and-thrust belt. This is achieved by a multiscale structural analysis of the Sivas Basin (Turkey). Extensive field work and regional seismic lines interpretations helped to build a new and detailed geologic map of the central Sivas Basin and to provide a new tectonosedimentary framework highlighting the influence of salt tectonics and the regional shortening, starting in the Late Eocene by the autochthonous evaporite deposition. This level is remobilized by the northward migrating sedimentary load, shortening and tilting of the basin southern margin during propagation of the foreland fold-and-thrust belt. Evaporite flow is recorded by the withdrawal of a primary generation of continental Oligocene minibasins which are then covered by an evaporite canopy. The canopy extending northward allows the development of second generation of continental to shallow marine mini-basins from Oligocene to Middle Miocene. Secondary minibasins initiation in the central part of the Basin, is characterized by sub-circular minibasins surrounded by polygonal diapirs and walls. Flanking these minibasins, a large variety of halokinetic structures is described: halokinetic sequences (hooks and wedges), composite halokinetic sequences and megaflaps. Preliminary sand-box modeling study suggests the development of thesehalokinetic structures both with and without shortening. Furthermore, minibasins geometries are closely similar to those imaged or mapped in other salt provinces suggesting that mini-basin withdrew is first control by sedimentary load, probably due to decoupling by the salt. However, the fractures and anisotropy of magnetic susceptibility analyses suggests the record of shortening since the minibasins initiation. The increase influence of regional shortening on the minibasins domain is expressed by salt walls and diapirs squeezing inducing: (i) the development of linear mini-basins perpendicular to the shortening direction, (ii) salt sheet emplacement and (iii) the translation/rotation of minibasins. The minibasins province produces a discontinuity for the fold-and-thrust belt propagation. Indeed, the minibasins province accommodates the shortening deformation along the polygonal network of salt walls and diapirs forming multidirectional structures. Furthermore, the regional shortening accommodation by salt structures squeezing produce an evaporitic remobilization and migration of a salt canopy toward the foreland basin. / Bu doktora tezi/çalışması, bir önülke kıvrım ve bindirme kuşağının evrimi sırasında minihavzaların çekilmesi ve bölgesel kısalma arasındaki etkileşimi konu edinir. Çoklu ölçekteki bu yapısal analiz Sivas Havzası (Türkiye) ölçeğinde gerçekleştirilmiştir. Kapsamlı saha çalışması ve bölgesel olarak sismik kesitlerden ortaya çıkarılan yorumlamalar, Sivas Havzası’nın orta kesiminde detaylı bir jeolojik haritalama yapımına yardımcı olmuş ve otokton evaporit depolanmasının başladığı Geç Eosen’den başlayarak havza için tuz tektoniği ve bölgesel kısalmanın etkisindeki yeni bir tektono-sedimanter çatının ortaya çıkarılmasına neden olmuştur. Söz konusu seviye, önülke kıvrım ve bindirme kuşağının ilerlemesisüresince kuzeye doğru sedimanter dolgunun göçüyle birlikte havzanın güney kenarında kısalıma uğrayarak ve eğim kazanarak remobilize olmuştur. Evaporit akışı, kıtasal Oligosen minihavzalarının ilksel olarak oluşumundan sonra çekilmesine bağlı olarak gözlenmiş ve sonrasında evaporit yaygılarıyla örtülmüştür. Kuzeye kadar uzanan bu yaygı, Oligosen-Orta Miyosen arasında kıtasaldan sonra sığ denizel tipteki ikincil minihavzaların gelişimine de neden olmuştur.Havzanın orta kesimindeki ikincil minihavza başlangıcı, poligonal diyapir ve duvarlar tarafından çevrelenen dairesel minihavzalarla karakterize olur. Bu minihavzaların kanatlarında halokinetik yapılar tanımlanmıştır. Kanca (hook) ve kama (wedge) tiplerde olmak üzere halokinetik seriler, kompozit halokinetik seriler ve megaflaplar bu yapılar arasında sayılabilir. Çalışmanın başlangıcında yapılan kum kutusu model deneyi, bu halokinetik yapıların kısalmayla veya kısalma olmaksızın geliştiğini göstermiştir. Buna ek olarak minihavzaların geometrisi, muhtemelen tuzun ayrışmasından dolayı tortul yükün ilkkontrolünden dolayı çekilen diğer tuz bölgelerinde önerilen haritalanmış minihavzalara benzerdir. Bununla birlikte kırık ve manyetik suseptibilite analizleri, minihavzaların başlangıcından itibaren kısalmanın kayıt edilebilmesi hakkında fikir vermektedir. Minihavza bölgelerindeki bölgesel kısalımın artışı, tuz duvarları ve diyapirlerin sıkışmasıyla birlikte(i) kısalma yönüne dik durumdaki çizgisel minihavzaların gelişimi, (ii) tuz örtülerinin yerleşimi ve (iii) minihavzaların yer değiştirmesi veya dönmesiyle açıklanır. Minihavzalar bölgesi, kıvrım ve bindirme kuşağının gelişimi için bir süreksizlik üretir. Aslında, minihavzalar birçok yönde yapılar oluşturarak tuz duvarları ve diyapirlerin polygonal şekildeki yerleşimi boyunca kısalma deformasyonuna eşlik eder. Üstelik, tuz yapılarının eşlik ettiği bölgesel kısalma önülke havzalarına doğru evaporitik bir göçe de neden olmaktadır.

Les avalanches de débris, qui résultent du démantèlement des flancs des édifices volcaniques et montagneux, sont des écoulements granulaires rapides et dangereux dont le monteur est la gravité et qui présentent des distances de transport extrêmement importantes. La dynamique de leur mise en place et leurs mécanismes de transport permettant cette très grande mobilité sont des phénomènes qui demeurent encore mal compris. De nombreux modèles existent pour expliquer la grande mobilité des avalanches de débris et incluent des processus basés sur la lubrification ou la fluidification de la masse granulaire mais également sur le phénomène de désintégration dynamique des éléments. Cependant la grande majorité des modèles proposés souffre du manque d’observations de terrain et de quantification de l’évolution des matériaux au cours de leur transport au sein de la masse granulaire. Afin d’identifier les principaux mécanismes de transport des avalanches de débris, nous proposons dans ce travail une étude de terrain détaillée de dépôts d’avalanches de débris volcaniques qui résultent du démantèlement d’un volcan bouclier océanique, le Piton des Neiges (île de La Réunion, océan Indien). L’approche est couplée à un examen morphométrique (dimension fractale et circularité), exoscopique et granulométrique des particules présentes dans les dépôts. Elle est complétée par l’examen de la fabrique des dépôts basée sur l’anisotropie de la susceptibilité magnétique (ASM). Les données obtenues nous permettent de mettre en évidence une évolution de la dynamique de transport et de mise en place des dépôts d’avalanches de débris depuis les zones sources jusqu’aux domaines de dépôt distaux. On montre également que la désintégration dynamique et le gonflement dispersif qui l’accompagne opèrent tout au long du transport et à toutes les échelles au-dessus d’une limite inférieure de broyage à 500 μm. En dessous de cette limite, la réduction granulométrique résulte uniquement de processus d’attrition par friction entre les particules. La grande mobilité des avalanches de débris pourrait ainsi être expliquée par l’effet combiné de la libération d’énergie élastique par la désintégration dynamique des particules > 500μm et par une réduction de la friction interne à la matrice liée aux interactions dispersives des particules fines (< 500 μm). L’ensemble des données permettent également de préciser les directions de transport et l’ampleur des avalanches de débris liées aux déstabilisations du massif du Piton des Neiges. / Debris avalanches, resulting from flank collapses that shape volcanic and mountainous edifices are rapidand dangerous gravity-driven granular flows that travel long run out distances. The dynamic and the transport mechanisms behind this high mobility remain poorly understood. The numerous models proposed to explain this high mobility include processes based on lubrication or fluidisation of the granular mass of the flow body, but also the dynamic disintegration of the transported particles. To date,all these proposed mechanisms lack observational support and quantification of the state of the particles of the granular mass during the transport. To identify the main transport mechanisms, we propose here detailed field studies of volcanic debris avalanches deposits resulting of flank-collapse events on an oceanic shield volcano, the Piton des Neiges (La Réunion Island, Indian Ocean). This study has been combined with morphometric (fractal dimension and circularity), exoscopic and grain-size analyses. Moreover, the fabric of the deposits has been investigated by with the characteristics of the anisotropy of the magnetic susceptibility (ASM). From these data we highlight a proximal to distal evolution of the debris avalanches transport and emplacement dynamics. We demonstrate that syn-transport dynamic disintegration continuously operates with the distance from the source down to a grinding limit of 500μm. Below this limit, the particle size reduction exclusively results from the attrition of the particles by frictional interactions. Thus, the exceptional mobility of debris avalanches may be explained by thecombined effect of elastic energy release during the dynamic disintegration of the larger clasts (> 500μm) and frictional reduction within the matrix due to the dispersive interactions between the finer particles (< 500 μm). All these data also allow to specify the transport direction and the approximate size of the debris avalanches related to the Piton des Neiges destabilisations.