Orientador: Rubens Nisie Tango / Banca: Alexandre Luíz Souto Borges / Banca: Sebastião Ribeiro / Resumo: O objetivo deste estudo foi desenvolver um novo formato de pilar protético estético em zircônia (3Y-TZP) visando suprimir a utilização do parafuso trespassante utilizado no formato convencional de pilares protéticos em zircônia. Inicialmente foi feita a caracterização do material utilizado na técnica de colagem de barbotina (slip casting) através da confecção de uma barra que teve suas propriedades mecânicas, módulo de elasticidade (E) e coeficiente de Poisson (), grau de contração e dimensão de suas partículas após sinterização avaliados pelos métodos de frequências naturais de vibração e microscopia eletrônica de varredura (MEV), respectivamente. Previamente à confecção do pilar protótipo, este teve seu comportamento mecânico avaliado e comparado a um pilar de 3YTZP convencional com parafuso trespassante pela análise por elementos finitos (FEA) durante sua instalação em implante e recebendo carga oblíqua simulando força de mastigação (210,5 N). O protótipo foi confeccionado pela técnica de colagem de barbotina em um molde de gesso obtido a partir de uma duplicata ampliada em cera. A densidade final foi avaliada pelo método de Archimedes em água. Obteve-se o módulo de elasticidade de 187,97 ± 4,84 GPa e coeficiente de Poisson de 0,19 ± 0,04 para o material. O grau de contração de sinterização foi de 58 vol% e o tamanho do grão foi de 0,705 ± 0,424 μm. Na análise por FEA verificou-se concentrações de tensões na região inicial da rosca para ambos os pilares, e durante o carregamento foram observadas tensões de tração no lado em que incidiu a carga, com presença de tensões de compressão no lado oposto. Ainda, observou-se durante o carregamento do pilar protético convencional concentração de tensão na região do pescoço do parafuso trespassante. A densidade final obtida para o pilar protótipo em 3Y-TZP foi de 95,68% em ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to develop a new esthetic zirconia (3YYTZP) implant abutment shape to suppress the use of the fixing screw commonly used by the conventional zirconia abutments. A material characterization, Young's modulus (E), Poisson's rate (), shrinkage and particles dimensions after sintering was performed for a bar shape specimen obtained by slip casting evaluated by the natural torsional and flexural vibration frequencies and scanning electron microscope (SEM), respectively. Previously to the prototype abutment confection, its mechanical behavior was evaluated and compared to a conventional zirconia abutment with a fixing screw by finite element analisys (FEA) simulating the abutment installation and oblique loading (210.5 N). The prototype was confectioned by the slip casting technique using a gypsum mould obtained from a wax expanded replica. The abutment had its density measured by Archimedes' method. Through the natural vibration frequencies a Young's modulus of 187.97 ± 4.84 GPa and a Poisson's rate of 0.19 ± 0.04 were obtained for the material. The shrinkage was 58 vol% and the grain size was 0,705 ± 0,424 μm . The FEA showed stress concentration at the first thread pitch for both abutments, and tensile stress concentration were observed at the side that received the oblique load with compressive stress at the opposite side. Whereas, for the conventional abutment model a stress concentration was observed at the screw's stem. The final density for the zirconia prototype abutment was 95.68% from the theoretical density (6.12 g.cm-3). The zirconia abutment obtained by slip casting presented satisfactory physical properties. The suppressing of the fixing screw could provide better performance to the abutment due to the lack of stress concentration in the screw when an oblique load is applied, when evaluated by FEA / Mestre

Cette thèse étudie les instabilités dynamiques des milieux granulaires modèles saturés à l’aide d’un appareil triaxial classique. Les instabilités englobent la liquéfaction et les effondrements en compression isotrope drainée, les frottements saccadés en compression triaxiale drainée. Ces instabilités apparaissent spontanément à des contraintes effectives de confinement imprévisibles. Elles sont accompagnées de très rapides et très fortes surpressions interstitielles, malgré un drainage approprié; ce que ne présentent pas les milieux granulaires naturels. En compression isotrope drainée (consolidation), des effondrements locaux naissent instantanément. En compression triaxiale drainée, on observe de larges frottements saccadés quasi-périodiques caractérisés par des déformations volumiques et axiales contractantes. De temps en temps, ces effondrements et frottements saccadés locaux peuvent se développer en liquéfaction menant à une destruction complète de la structure granulaire. Les données à haute résolution temporelle issues de ce travail ont permis la découverte d’une nouvelle famille de liquéfaction dynamique et statique. L’étude des émissions acoustiques passives a permis l’identification de signature spectrale caractéristique. Pour les frottements saccadés, la phase de glissement peut être interprétée comme une consolidation dynamique, limitée par l’unique surface en dessous de la ligne critique de rupture dans le plan des contraintes effectives. La séquence temporelle précise des événements exclut que la pression interstitielle soit la cause principale des instabilités. Cependant, le rôle important de la surpression interstitielle est démontré dans des relations quantitatives entre les incréments de contraintes, et de déformations et l’éphémère surpression interstitielle stabilisée développée pendant la phase de glissement. Cela montre finalement la nature quasi-déterministique de ces instabilités dynamiques. Ces relations empiriques sont basées uniquement sur l’amplitude maximale de l’accélération verticale de très courte durée et sont gouvernées indépendamment par la pression de confinement et par l’indice des vides. La similarité de la surpression interstitielle entre différentes instabilités suggère fortement quelques mécanismes similaires de déclenchement, probablement à partir de ré-arrangements de la micro-structure granulaire. / This thesis reports a laboratory study on the dynamic instabilities of model saturated granular material using a triaxial apparatus. The term instability consists of isotropic collapse and liquefaction under isotropic compression and of stick-slip under triaxial compression in drained condition. The instabilities spontaneously occur at unpredictable effective stress with unexpected buildup of excess pore pressure irrespective of fully drained condition, contrasting with the instability-free behaviour of natural granular materials. In isotropic compression, instantaneous local collapse happens and in triaxial compression, very large and quasi-periodic stick-slip occurs with sudden volumetric compaction and axial contraction. Sometimes, these local failures (collapse and stick-slip) can develop into total liquefaction failure, destroying completely the granular structure. High time-resolved data permit the discovery of a new family of dynamic and static liquefaction. Passive acoustic measurements allow the identification of typical spectral signature. For stick-slip phenomenon, the slip phase with constant duration of stress drop can be interpreted as dynamic consolidation at constant deviatoric stress, limited by a unique boundary inside the critical state line in the effective stress plane. The precise temporal sequence of mechanical measurements excludes the generated pore pressure as the main cause of the instabilities. However, the role of pore pressure is emphasised by consistent quantitative relations between the amplitude of incremental stresses, incremental strains and the ephemeral stabilised excess pore pressure developed during the dynamic event, leading to the quasi-deterministic nature of granular instabilities. These empirical relations are based only on the short-lived maximum vertical acceleration and governed separately by the confining pressure and the initial void ratio. The similarity of pore pressure evolution for different kinds of instability strongly suggests some common speculative triggering mechanisms, probably originated from different rearrangements of the granular micro-structure.

《睡虎地秦簡•日書》自西元1975年底出土至今已有一段時日，相較於其它出土的《日書》版本而言是較為完整的，引起許多學者熱烈探討且著作頗豐。本論文以有別於其他學者的研究觀點，以文化人類學、考古學、文字學、宗教民俗等為研究方向，並相互比對、釋讀考古資料及歷史文獻，透過字句、語境的詮釋，以探索《睡虎地秦簡•日書》中的鬼神觀和豐富的巫術活動，並分析秦人的巫術信仰及巫術思維，試圖還原秦地巫術文化中的部分面貌。再以商周至兩漢之間的巫術活動的衍變，尋求巫術文化的歷時性脈絡。 / It has been a while since “Shuihudi Bamboo Slips -- Rishu” was excavated in the year 1975. Compared with other copies of “Rishu”, it is more complete and is the subject of scholarly discussion and literature. This study uses a different approach -- that of cultural anthropology, archeology, philology, religion and folklore -- to compare, contrast and interpret the archaeological data and historical documents, as well as to explore the spirits and deities, and witchcraft activities, in “Shuihudi Bamboo Slips – Rishu” through the word usage and context. Finally, the study helps to analyze the Qins’ belief and thinking in witchcraft, and attempts to trace the history of witchcraft culture based on the evolution of witchcraft activities from the Shang and Zhou Dynasty to the Han Dynasty.

Cette thèse vise à étudier les propriétés thermo-poro-mécaniques de roches de faille, à partir de l'analyse structurale et microstructurale d'une faille aujourd'hui à l'affleurement et à partir d'expériences menées en laboratoire, en vue de déterminer les processus qui contrôlent l'efficacité de deux mécanismes responsables de d'affaiblissement cosismiques : la pressurisation thermique et le mécanisme d'affaiblissement par drainage. L'étude de terrain a été conduite sur deux affleurements appartenant à une faille décrochante potentiellement active appartenant au système de failles du Chugoku occidental (Japon) : la faille d'Usukidani. Le travail expérimental a quant à lui été mené dans le laboratoire de déformation des roches de l'Université de Kyoto. Les résultats majeurs de ce travail sont exposés ci-dessous. <br /> Les propriétés hydrologiques et poro-élastiques de la gouge et de la brèche de la faille d'Usukidani ont été determinées à partir d'échantillons prélevés sur le terrain. Ces données hydrauliques ont ensuite été utilisées dans un modèle numérique afin d'évaluer l'importance du phénomène de pressurisation thermique dans le cas d'un glissement cosismique le long de la zone de glissement principale et le long de zones de glissement secondaires. Les résultats de cette modélisation suggèrent que le mécanisme de pressurisation thermique n'est efficace que si la rupture reste localisée le long des zones de glissement contenant de la gouge, avec comme facteur de contrôle l'épaisseur de cette zone de glissement. <br /> Afin d'identifier les processus dynamiques particulaires responsables de l'affaiblissement cosismique dans la zone de glissement, plusieurs essais de friction ont été menés sur une machine à cisaillement annulaire. Ces expériences ont été conduites à des vitesses cosismiques (équivalentes à 0,09, 0,9 et 1,3 m/s) en conditions humides ou conditions sèches. Les données obtenues montrent que quelles que soient les conditions d'humidité initiales, les failles simulées montrent toutes un affaiblissement lors du déplacement. Un examen détaillé des microstructures des gouges cisaillées obtenues une fois l'équilibre frictionnel atteint permet de définir deux types de microstructures impliquant deux régimes de déformation : un régime de déformation par roulement avec la formation d'agrégats argileux, et un régime de déformation par glissement avec la formation d'une zone de cisaillement complexe localisée à l'interface gouge-éponte. L'affaiblissement observé lors des expériences semble être lié à une diminution de la proportion de grains roulants par rapport à celle de grains glissants, et semble être favorisé par le développement des agrégats argileux, lesquels sont contrôlés par la teneur en eau.<br /> A partir d'un modèle numérique (P2 FEM) et des données de contrainte cisaillante obtenues lors des essais de friction, il a été possible de calculer l'évolution de la température de la gouge en fonction du déplacement. Les résultats suggèrent que la distance dc pourrait représenter la distance nécessaire à une faille pour produire et diffuser assez de chaleur afin de casser les ponts d'eau capillaire (forces d'adhésion) et ainsi permettre à l'eau contenue dans la gouge d'être libérée. Ce mécanisme est appelé mécanisme d'affaiblissement par drainage.

Le travail présenté dans cette thèse porte sur la modélisation et la commande non linéaire le système du forage pétrolier. La problématique principale consiste à proposer un modèle de forage non linéaire et à élaborer un ensemble de stratégies de commande avancées pour améliorer les performances du trépan.<br />A l'heure actuelle, les commandes des systèmes de forage pétroliers sont réalisées à l'aide de régulateurs classiques PI ou PID. Leurs performances se dégradent notablement lors de vibration de torsion causée par le « stick- slip », phénomène qui peut provoquer des couples non linéaires et donc endommager le trépan et le train de tiges. Par conséquent, il est nécessaire de disposer de systèmes de commande plus performants afin de mieux répondre aux exigences et aux performances demandées.<br />En dépit des diverses lois de commandes linéaires tentatives pour commander ce système mais qui ne garantissent pas la stabilité vis-à-vis des incertitudes. Ceci nous a conduits à proposer une modèle non linéaire en prenant en compte la totalité de l'information du phénomène du stick-slip, ce qui a conduit à une modélisation globale du forage rotary approchant donc au mieux le comportement réel de la plate-forme pétrolière. Pour cela, nous avons suggéré deux approches pour améliorer les performances du système de forage rotary:<br />• Commande par la technique de linéarisation par bouclage.<br />• Développement d'une commande par la technique des modes glissant associé à la commande linéarisation par Bouclage.<br />Comme le système de forage est généralement, est un système soumis aux incertitudes paramétriques, nous avons proposé, de plus, une nouvelle loi de commande non linéaire par Backstepping permettant de mieux améliorer la réponse de la vitesse de rotation du trépan.<br />Ces trois stratégies de commandes apparaissent la première fois dans ce domaine et la approche de Backsteping s'avère la meilleure. Les résultats de simulations obtenus dans les trois cas sont concluants et la synthèse par Backstepping montré la supériorité de, où la question de robustesse a pu être considérée.

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The aim of this work is the development of mechanical models on a mesoscopic level for the analytical description of the material properties of textile reinforced concrete (TRC). For the modelling of the heterogeneous structure of TRC the concept of representative volume elements (RVE) is used. RVEs are representative for the mesoscopic structure. The overall material behaviour on the macroscopic level is obtained by means of homogenisation of the heterogeneous material behaviour on the mesoscopic level. Based on the micro mechanical solution of the elastic field of an ellipsoidal inclusion according to Eshelby a model for the determination of the material behaviour for multi-directional reinforced finegrained concrete is developed. An effective field approximation considers the interaction of the differentially orientated reinforcements in an averaged sense. Microcracks are included by additional strains in the representative volume element. The average interaction between the microcracks and the reinforcements is considered by an effective field approximation. As a criteria for the initiation of the macro cracking a critical microcrack density parameter is implemented in the mechanical model. The microcracks accumulate to macrocracks if the microcrack density parameter in the RVE exceeds this critical value. For the mechanical modelling of the bond behaviour between roving and matrix after macro cracking a multiple linear shear stress-slip relation is used. This shear stress-slip relation considers adhesion, damage and failure of the interface between roving and matrix. Hence experimentally measured pullout force-displacement curves can be simulated realistically. / Gegenstand dieser Arbeit ist die Entwicklung mechanischer Modelle auf der Mesoebene zur analytischen Beschreibung des makroskopischen Materialverhaltens von textilbewehrtem Feinbeton. Für die Modellierung der heterogenen Struktur wird das Konzept der repräsentativen Volumenelemente (RVE), die für die Mesostruktur des betrachteten Verbundwerkstoffes repräsentativ sind, verwendet. Der Übergang von dem heterogenen Materialverhalten auf der Mesoebene zum mittleren Materialverhalten auf der Makroebene erfolgt mittels Homogenisierung. Auf Basis der mikromechanischen Grundlösung für ellipsoidförmige Einschlüsse nach Eshelby wird ein Modell entwickelt, das die Ermittlung des Materialverhaltens von multidirektional bewehrtem Feinbeton ermöglicht. Durch die Anwendung einer Effektive-Feld-Theorie wird die gegenseitige Beeinflussung der unterschiedlich orientierten Bewehrungen in einem gemittelten Sinn betrachtet. Die ab einer bestimmten makroskopischen Beanspruchung entstehenden Mikrorisse berücksichtigt das mechanische Modell über einen durch die Mikrorisse hervorgerufenen zusätzlichen Verzerrungsanteil im RVE. Mittels der verwendeten Effektive-Feld-Theorie kann eine mittlere Beeinflussung zwischen den Mikrorissen und der Rovingbewehrung erfasst werden. Für den Übergang von der Mikrorissbildung zur Makrorissbildung wird für das mechanische Modell der Begriff einer maximalen Mikrorissdichte eingeführt. Überschreitet die Mikrorissdichte im RVE diesen maximalen Wert, vereinigen sich die Mikrorisse zu Makrorissen. Zur Beschreibung des mechanischen Verbundverhaltens zwischen Roving und Matrix beim Rovingauszug am Makroriss wird eine multilineare Schubspannungs-Schlupf-Beziehung verwendet, welche die Schädigung des Roving-Matrix-Verbundes bis hin zum vollständigen Versagen erfasst. Damit lassen sich experimentell ermittelte Kraft-Verformungskurven an Zugproben wirklichkeitsnah abbilden.

El fallo resistente de las losas mixtas se produce generalmente por el deslizamiento longitudinal entre la chapa nervada de acero y el hormigón. La dificultad de diseño de chapas para losas mixtas reside en asegurar su comportamiento efectivamente mixto; en diseñar sistemas de retención que consigan una elevada resistencia al deslizamiento longitudinal relativo entre acero y hormigón.Para cumplir las funciones encomendadas a la chapa, encofrado perdido y armadura de tracción, existen muchos tipos de diseño, creados sobre la base de la experiencia acumulada y cuya eficacia debe siempre ser evaluada empíricamente.Los actuales diseños de chapas incorporan un patrón de embuticiones que se repiten a lo largo de toda la longitud de la chapa. Su función es dificultar el deslizamiento longitudinal, análogamente al corrugado de las barras para el armado del hormigón, pero sus mecanismos resistentes son completamente distintos. En las losas mixtas, el efecto de cuña de las embuticiones transforma el deslizamiento en esfuerzos perpendiculares a la chapa que provocan su flexión transversal y, en algunos casos, la desconexión total.El ángulo de conformado que define los nervios de la losa, la posición de las embuticiones, su profundidad, longitud, etc., son algunos de los parámetros importantes de diseño, ya que contribuyen significativamente a bloquear el deslizamiento. El proceso de diseño y optimización de esta geometría, y también la comprobación de su eficacia, se realiza actualmente de forma completamente empírica. También los métodos de cálculo adoptados por las normativas de todo el mundo para el cálculo de losas mixtas, están basados en parámetros experimentales, obtenidos del ensayo de modelos estándar reducidos. Estos ensayos intentan reproducir, con mayor o menor fidelidad, las condiciones reales de funcionamiento.Esta tesis se enmarca en una línea de investigación destinada a mejorar la conexión entre el acero y el hormigón de los actuales sistemas e idear conceptos innovadores que, a más largo plazo, puedan significar la conexión total sin deslizamiento.Se han desarrollado dos actividades principales:- Experimental: ensayos reducidos de Pull-out y ensayos de flexión de losas completas según método normativo m-k, instrumentadas con galgas extensométricas.- Numérica: establecimiento de un procedimiento validado para la elaboración de modelos tridimensionales de elementos finitos. Simulación del fallo por deslizamiento y estudio paramétrico descriptivo.Con el objetivo general de aportar conocimiento y afianzar la comprensión del comportamiento mecánico de la losa mixta, la tesis aborda el estudio numérico y experimental del fallo por deslizamiento longitudinal, consiguiéndose las siguientes aportaciones particulares:- Procedimiento de simulación numérica local tridimensional y no-lineal del deslizamiento entre la chapa de acero y el hormigón, con el que se describe exactamente la mecánica de funcionamiento de algunos diseños existentes en el mercado.- Análisis del efecto que tienen distintos parámetros físicos y geométricos en la resistencia de la losa mixta frente al deslizamiento longitudinal: rozamiento, profundidad de embutición, longitud, posición, ángulo de conformado, espesor de la chapa, etc., mediante los modelos de elementos finitos.- Evaluación, mediante los modelos numéricos, del perfil de distribución de tensiones longitudinales en tracción simple, con el fin de cuantificar las sombras de tensión que provocan las embuticiones,- Evaluación de la influencia de las condiciones superficiales de la chapa durante el hormigonado en la resistencia al deslizamiento.- Evaluación de la uniformidad de distribución de esfuerzos rasantes transmitidos por las embuticiones. Las losas ensayadas a flexión se han instrumentado, en los tramos de luz rasante, con galgas extensométricas fijadas en varias secciones situadas a distintas distancias de los apoyos.- Recomendaciones generales de diseño. Aplicación al diseño del nuevo perfil "T80" y ensayo.El nuevo perfil "T80", ha sido ya producido en serie, comercializado y puesto en obra en edificios de gran altura, presentando resultados muy satisfactorios. / The resistant failure of composite slabs is generally due to longitudinal slip between the profiled steel sheet and concrete. The main goal when designing sheets for composite slabs, consists of ensuring its effective composite behaviour; conceiving retention systems that achieve higher longitudinal slip strengths.To carry out these functions entrusted to steel sheet, i.e. permanent formwork and traction reinforcement, lots of design types are available, created on the basis of prior experience and which effectiveness has to be evaluated empirically.Current sheet designs show a repeating embossments pattern all along the span. Its function is to inhibit the longitudinal slip in a similar way than the reinforcing bar corrugations for concrete; however, their resistant mechanisms are quite different. In the case of the composite slabs, the embossments wedge effect transforms the slip to normal efforts that produce the transversal bending of the sheet and, sometimes, the connection loss.The profiling shape that defines the ribs of the slab, the embossment locations, its depth, length, etc. are some of the main parameters that significantly contributes to lock the slip.Currently, the design and optimization processes for the geometry, and also the checking of its effectiveness, are just empirically evaluated.In the same way, also the composite slabs calculation methods adopted by all national and international standards are based on experimental parameters, obtained from the test of reduced specimens. These tests attempt to reproduce the real behaviour conditions.The framework of this thesis is a research line devoted to improve the longitudinal shear connection between steel and concrete of the current designs as well as conceive innovative concepts that might achieve the permanent connection.Two main activities have been developed:- Experimental: reduced Pull-out tests and standard m-k bending tests, with the use of strain gauges technology.- Numerical: state a validated procedure for making parametrical 3D non-linear finite elements models to simulate the failure micro-mechanics due to longitudinal slip. Within the global aim of improving the knowledge and to strengthen the comprehension of the micro-mechanical behaviour of the composite slabs, this thesis approach the numerical and experimental analysis of the longitudinal slip failure micro-mechanics, achieving the following particular contributions:- Stating a procedure for creating non-linear 3D finite elements models to simulate the slip between steel sheet and concrete, by which the failure mechanics of several existing designs has been exactly described and analysed.- Analysis of the shear strength dependency on several physical and geometrical parameters, such as: friction coefficient, embossment depth, length, location, profiling angle, sheet thickness, etc., by means of the above said FEM procedure.- Evaluation, by FEM, of the distribution of longitudinal stresses in simple traction, for quantifying the stress shadows due to embossments.- Effect of the sheet surface conditions, prior to setting the concrete, in the longitudinal shear strength.- Distribution analysis of the longitudinal shear forces transmitted by the embossments all along the shear span. Strain gauges have been bonded to the free steel surface of several composite slabs, in different locations along the shear span.- General design recommendations. Pre-design, optimization and test of the new "T80" open-rib profile.This new "T80" profile is being manufactured, commercialized, and used in many outstanding buildings and skyscrapers, showing very good results in comparison to other existing open-rib designs.

Ever since the first plate-tectonic model for the Appalachians was proposed, the Laurentian margin has been interpreted as having experienced a collision-related dynamo-thermal event during the Middle Ordovician Taconic orogeny. In the western Newfoundland Appalachians, evidence for this collision is well-preserved in the Dashwoods subzone. Nevertheless, rocks of the neighbouring Corner Brook Lake block (CBLB), which is located in the heart of the Laurentian realm, did not show evidence for such an event. Instead, it was affected by Early Silurian Salinic deformation and associated peak metamorphism. Even though this difference in Early Palaeozoic tectonic history between the Dashwoods and the CBLB is widely known, it has not been satisfactorily explained. To better understand the Early Palaeozoic history of the region, in particular to test and better explain the lack of a Taconic dynamo-thermal event in the CBLB, field mapping, microscopic work, and U-Pb and 40Ar/39Ar geochronological studies were undertaken in the western and northern part of the Dashwoods subzone, and in the southern part of the CBLB. In addition, the kinematic history of the Baie Verte-Brompton Line - Cabot Fault Zone (BCZ), the tectonic zone that separates the two unique tectonic fragments, was studied. The western and northern parts of the Dashwoods subzone contain variably foliated igneous units of Middle Ordovician age (ca. 460 Ma) that are associated with the regionally voluminous Notre Dame continental arc. A ca. 455 Ma conjugate set of late syn-tectonic pegmatite dykes in the BCZ demonstrates a dextral sense of shear along the BCZ (DBCZ-1) during the Late Ordovician to earliest Silurian, and constrains the minimum age of the main phase of ductile deformation in the Dashwoods subzone. The fault-bounded CBLB has been affected by a single west-vergent deformational event, constrained between ca. 434 and ca. 427 Ma. More importantly, no evidence – neither petrographic nor geochronological – is present that would indicate that the CBLB was affected by a significant Taconic dynamo-thermal event. Hence, the CBLB and Dashwoods could not have been juxtaposed until after the late Early Silurian. Furthermore, the basement to the CBLB is devoid of any Grenville (sensu lato; ca. 1.0-1.3 Ga) U-Pb ages, which is in sharp contrast with crystalline basement elsewhere in the region, such as the Long Range Inlier. Therefore, it is highly unlikely that the CBLB represents the para-autochthonous leading edge of the Laurentian craton in the Newfoundland Appalachians, as commonly accepted. The CBLB is interpreted as a suspect terrane that has moved over 500 km parallel to the strike of the orogen. Docking to the external Humber Zone is likely to have occurred during the Early Silurian. Final juxtaposition with the Dashwoods took place after the late Early Silurian (post-Salinic) as a result of protracted dextral movement along the BCZ (DBCZ-2 and DBCZ-5). Current tectonic models for the Newfoundland Appalachians mainly focus on well-documented Early Palaeozoic orthogonal convergence of various terranes with the Laurentian margin, but large-scale orogen-parallel movements have rarely been considered. The possibility of large-scale strike-slip tectonics documented here, in addition to the convergent motions, may have significant implications for the tectonic interpretation of the Early Palaeozoic evolution of the Newfoundland Appalachians.

Ever since the first plate-tectonic model for the Appalachians was proposed, the Laurentian margin has been interpreted as having experienced a collision-related dynamo-thermal event during the Middle Ordovician Taconic orogeny. In the western Newfoundland Appalachians, evidence for this collision is well-preserved in the Dashwoods subzone. Nevertheless, rocks of the neighbouring Corner Brook Lake block (CBLB), which is located in the heart of the Laurentian realm, did not show evidence for such an event. Instead, it was affected by Early Silurian Salinic deformation and associated peak metamorphism. Even though this difference in Early Palaeozoic tectonic history between the Dashwoods and the CBLB is widely known, it has not been satisfactorily explained. To better understand the Early Palaeozoic history of the region, in particular to test and better explain the lack of a Taconic dynamo-thermal event in the CBLB, field mapping, microscopic work, and U-Pb and 40Ar/39Ar geochronological studies were undertaken in the western and northern part of the Dashwoods subzone, and in the southern part of the CBLB. In addition, the kinematic history of the Baie Verte-Brompton Line - Cabot Fault Zone (BCZ), the tectonic zone that separates the two unique tectonic fragments, was studied. The western and northern parts of the Dashwoods subzone contain variably foliated igneous units of Middle Ordovician age (ca. 460 Ma) that are associated with the regionally voluminous Notre Dame continental arc. A ca. 455 Ma conjugate set of late syn-tectonic pegmatite dykes in the BCZ demonstrates a dextral sense of shear along the BCZ (DBCZ-1) during the Late Ordovician to earliest Silurian, and constrains the minimum age of the main phase of ductile deformation in the Dashwoods subzone. The fault-bounded CBLB has been affected by a single west-vergent deformational event, constrained between ca. 434 and ca. 427 Ma. More importantly, no evidence – neither petrographic nor geochronological – is present that would indicate that the CBLB was affected by a significant Taconic dynamo-thermal event. Hence, the CBLB and Dashwoods could not have been juxtaposed until after the late Early Silurian. Furthermore, the basement to the CBLB is devoid of any Grenville (sensu lato; ca. 1.0-1.3 Ga) U-Pb ages, which is in sharp contrast with crystalline basement elsewhere in the region, such as the Long Range Inlier. Therefore, it is highly unlikely that the CBLB represents the para-autochthonous leading edge of the Laurentian craton in the Newfoundland Appalachians, as commonly accepted. The CBLB is interpreted as a suspect terrane that has moved over 500 km parallel to the strike of the orogen. Docking to the external Humber Zone is likely to have occurred during the Early Silurian. Final juxtaposition with the Dashwoods took place after the late Early Silurian (post-Salinic) as a result of protracted dextral movement along the BCZ (DBCZ-2 and DBCZ-5). Current tectonic models for the Newfoundland Appalachians mainly focus on well-documented Early Palaeozoic orthogonal convergence of various terranes with the Laurentian margin, but large-scale orogen-parallel movements have rarely been considered. The possibility of large-scale strike-slip tectonics documented here, in addition to the convergent motions, may have significant implications for the tectonic interpretation of the Early Palaeozoic evolution of the Newfoundland Appalachians.