La chaîne actuelle du Tian Shan (Asie centrale) est considérée comme une conséquence directe de la réactivation d'une ceinture orogénique du Paléozoïque due à la collision Inde-Asie, au Cénozoïque. Un travail détaillé a été réalisé le long du piémont nord de la chaîne en intégrant les observations géologiques de terrain, analyses structurales, profils sismiques, nouvelles mesures des anomalies gravimétriques et des données de forages. Tout d'abord cette étude apporte de nouvelles preuves directes, à différentes échelles, sur l'existence d'un paléo-relief majeur le long du front nord du Tian Shan au cours du Mésozoïque, et plus particulièrement pendant le Jurassique. Deuxièmement, la quantité de raccourcissement calculée à travers cette ceinture de plis et chevauchements nord du Tian Shan est relativement faible et les structures reconnues le long du front de la chaîne présentent une hétérogénéité latérale forte. Ainsi, alors qu’un chevauchement du socle paléozoïque sur les séries sédimentaires mésozoïques et cénozoïques du bassin est remarquablement exposé le long de certaines vallées, d'autres sections montrent que les séries sédimentaires du Trias au Jurassique peuvent être suivies de manière continue, depuis le bassin jusque sur le toit du socle Paléozoïque où ils reposent en discordance relativement haut dans la chaîne. Quatre coupes géologiques ont été construites par l'intégration des données pluridisciplinaires acquises. La restauration de ces coupes montre que les taux de raccourcissement sont inférieurs à 20% et peuvent descendre à un minimum de 6%. Ces observations suggèrent que le piémont nord du Tian Shan est plutôt «jeune» et que la chaîne d’avant pays est encore à un stade primaire de son évolution tectonique. En d'autres termes, le piémont nord du Tian Shan peut être considéré comme un exemple type de front de chaîne immature. / The modern Tian Shan (Central Asia) is considered as a direct consequence of the reactivation of a Paleozoic orogenic belt due to the India – Asia collision, during Cenozoic times. A detailed work has been investigated along the northern piedmont of Tian Shan, integrating the field work, structural analysis, seismic profile data, gravity anomaly measurements and drilled wells. Firstly, this study brings new and direct evidences, at different scales, for the existence of a major paleo-relief along the northern Tian Shan range during Mesozoic, and particularly during Jurassic times. Secondly, the calculated shortening amount in the northern piedmont of Tian Shan is rather small and the structural pattern of its front is heterogeneous along-strike. While, thrusting of the Paleozoic basement on the Mesozoic or Cenozoic sedimentary series of the basin is remarkably exposed along several river valleys, other sections display continuous Triassic to Jurassic sedimentary series from the basin to the range where they unconformably overlie on the Carboniferous basement. Four cross-sections are made by integrating multi-method data, showing that shortening amounts are less than 20% and could be even until to 6%. This suggests that the Tian Shan intracontinental range is rather “young” and still at a primary stage of its tectonic evolution. In other words, its front may be considered as a typical example of an immature range front.

Se estudia una porción de la Faja Plegada y Corrida de Malargüe en el sur de los Andes Centrales (Cordillera Principal), Mendoza, Argentina, entre los 34 40 - 35 de latitud sur y 69 - 70 de longitud Oeste. Este área se encuentra regionalmente vinculada en su génesis y evolución al margen continental activo de América del Sur. Se caracteriza por un basamento volcaniclástico-plutónico de edad Permotriásica al que sobreyace una secuencia sedimentaria Triásica a Terciaria diferenciada en los Grupos Cuyo, Lotena, Mendoza, Rayoso, Neuquén, Malargüe y unidades cenozoicas que en conjunto suman un espesor mayor a los 6200 metros. La construcción de este sector del orógeno, asociada a la tectónica andina, involucra al basamento definiéndose a la faja plegada y corrida de Malargüe como epidérmica gruesa. La deformación del basamento y su vinculación con la cubierta sedimentaria permite explicar algunos rasgos notables para las estructuras ándicas de este sector de la Cordillera Principal, como la variación en el rumbo, cambios en la longitud de onda de los pliegues, presencia de múltiples despegues dentro de la cubierta sedimentaria o grandes variaciones de acortamiento entre regiones próximas. El objetivo de esta tesis es desarrollar un modelo cinemático para este sector de la Cordillera Principal argentina, sustentado en un detallado trabajo de superficie y apoyado por los datos disponibles de perforaciones y sísmica. Se interpretan y reconstruyen tres secciones estructurales de 60 km de longitud orientadas en dirección Oeste-Este, subperpendiculares a la dirección relevada para las estructuras tectónicas asociadas a la orogenia andina. Los afloramientos del Grupo Cuyo ocupan la porción occidental de estas secciones, mientras que el Mesozoico medio y alto queda restringido al centro localizándose las unidades terciarias en el borde oriental. Se interpretan dos altos de basamento cuyo rasgo superficial corresponde a importantes sinclinorios, denominados alto del arroyo El Freno y alto del arroyo Blanco, siendo el corrimiento asociado a este último el responsable de la exhumación del Grupo Cuyo desplazándose como falla fuera de secuencia en el último estadio de la evolución del área. La deformación del basamento por fallamiento retrovergente asociado a corrimientos regionales provergentes se revela como una posibilidad altamente confiable para la resolución de problemas tectónicos tanto en este como en otros sectores de la Cordillera Principal. Existe un notable desarrollo espacial de zonaciones estructurales asociadas a la geometría que presenta el basamento para esta porción de la Faja Plegada y Corrida de Malargüe en respuesta al crecimiento y avance del zócalo deformado como resultado de la compresión andina. Se observa una secuencialidad de eventos que permite definir un modelo progresivo en el tiempo, en donde la zonación estructural producida en respuesta a la deformación del zócalo es posteriormente afectada por el desarrollo de una nueva estructura de basamento. Los acortamientos medidos sustentan la imposibilidad de la inversión tectónica como mecanismo de construcción y avance del frente montañoso para esta porción de la Faja Plegada y Corrida de Malargüe, debiendo considerarse aplicar esta posibilidad con mucha cautela en otros sectores de la Cordillera Principal. / This thesis involves the study of the Malargüe Fold and Thrust belt, part of the Central Andes at the southern Cordillera Principal, Mendoza province, Argentina (34 40 35 S and 69 - 70W). The tectonic setting and evolution of the area is controlled by the continental active margin of the South America plate. The Malargüe Fold and Thrust belt is characterized by a volcaniclastic-plutonic Permian-Triassic basement which overlies a sedimentary sequence represented by Cuyo, Lotena, Mendoza, Rayoso, Neuquén and Malargüe Groups and cenozoic units, with more than 6200 meters of thickness. Construction of the mountain front is related to Andean tectonics and involves basement thrust sheets, defining a thick-skinned fold and thrust belt in this particular site of the Central Andes. Relationship between basement and fault and fold sedimentary cover allow us to explain some particular features for Andean structures at the Atuel river valley, such as strike variations, fold wave-length changes, multiple detachments horizons located into the sedimentary cover or different shortening between near localities. The aim of this thesis is to develop a kinematic model for this zone of Cordillera Principal province, supported in a detail field work and well and seismic available data. Three West-East structural sections with 60 km of length are interpreted and reconstructed, subperpendicular to tectonic orientation mapped for Andean structures. Cuyo Group outcrops are located at the western side of the sections, while middle and upper Mesozoic remains restricted to the centre and tertiary deposits are located at the eastern side. According to this, two structural basement highs where interpreted named as arroyo El Freno high and arroyo Blanco high. Regional major thrust involved to the elevation of the arroyo Blanco high is interpreted as responsible of Cuyo Group exhumation, related to an out-of sequence displacement that affects folded Mesozoic sequence in the latest stadium of tectonic evolution of the area. Basement deformation associated to regional master foreland thrusts and the developed of backthrusting appears to be a high confident possibility of resolution of tectonics problems in this area as well in another places of Cordillera Principal Province. There is notable structural zonation related to the basement geometry at this site of Malargüe Fold and Thrust belt in response to the growing and forward movement of deformed crystalline basement as a result of Andean compression. A temporal sequence of events can be observed allowing us to define a progressive model, where the previous structural zonation is affected for a new local basement structure. Shortening measures support impossibility of tectonic inversion of rifting Triassic normal fault system as a viable mechanism of construction y evolvement of mountain front for this part of Malargüe Fold and Thrust belt; a carefully consideration to this option in the study of others sides of Cordillera Principal is suggested.

The Cordilleran Orogen affected majority of the western margin of ancient continental North America in the Cretaceous, which is well recorded in the Foreland Belt. The Mackenzie Mountains fold-and-thrust belt is located primarily in the westernmost Northwest Territories and easternmost Yukon Territory in northern Canada. The mountains are often described as the northern extension of the Rocky Mountains to the south which are one of the world’s best examples of a thin-skinned fold-and-thrust belt. Within the Mackenzie Mountains, Neo-Proterozoic through Cretaceous sedimentary rocks record the Laramide aged deformation, with a range of structures that vary in size and complexity. Previous mapping by the Geological Survey of Canada produced a series of reconnaissance maps that are still in use today, many of which are available in only black and white. This study is focused on a part of the 1:250 000 scale NTS 106A Mount Eduni map sheet from Geological Survey of Canada reconnaissance mapping in 1974. The study involved re-mapping a large panel at 1:50 000 scale to better understand the structural geometry, regional shortening and the depth of the underlying detachment level. Through systematic geologic mapping and structural analyses, this study presents a balanced regional cross-section, numerous serial cross-sections and a detailed geologic map of the study area, the Ten Stone Ranges Structural Complex. The serial cross-sections were used to define the geometry of the Cache Lake Fold, a large fault-bend-fold system that involves a folded thrust fault and complicated subsurface geometry. In addition to this, the sections confirmed that the TSRSC is a transfer zone whereby a series of thrust faults and décollement folds are responsible for much of the displacement and shortening in the Mount Eduni map sheet. The balanced regional cross-section was constructed across a number of key structural elements, in particular the Plateau Fault, a regional structure with a > 250 kilometer strike length and the subject of much debate as to its geometry. In addition to this structure, the cross-section transects the Cache Lake Fold and the Shattered Range Anticline, a regional box shaped anticline that was used for a “depth to detachment” calculation. By examining the regional detachment level estimated from the balanced cross-section and calculating the detachment depth using the Shattered Range Anticline the detachment depth was found to be – 11.3 kilometers below the current erosional level. This study is the first structural analyses of the Mount Eduni map sheet, particularly the Ten Stone Ranges Structural Complex, and has resulted in an estimate of the detachment depth for the area, a shortening estimate of > 7 kilometers across the 50 kilometer line of section and a displacement estimate for the Plateau Thrust of > 20 kilometers.

The Cordilleran Orogen affected majority of the western margin of ancient continental North America in the Cretaceous, which is well recorded in the Foreland Belt. The Mackenzie Mountains fold-and-thrust belt is located primarily in the westernmost Northwest Territories and easternmost Yukon Territory in northern Canada. The mountains are often described as the northern extension of the Rocky Mountains to the south which are one of the world’s best examples of a thin-skinned fold-and-thrust belt. Within the Mackenzie Mountains, Neo-Proterozoic through Cretaceous sedimentary rocks record the Laramide aged deformation, with a range of structures that vary in size and complexity. Previous mapping by the Geological Survey of Canada produced a series of reconnaissance maps that are still in use today, many of which are available in only black and white. This study is focused on a part of the 1:250 000 scale NTS 106A Mount Eduni map sheet from Geological Survey of Canada reconnaissance mapping in 1974. The study involved re-mapping a large panel at 1:50 000 scale to better understand the structural geometry, regional shortening and the depth of the underlying detachment level. Through systematic geologic mapping and structural analyses, this study presents a balanced regional cross-section, numerous serial cross-sections and a detailed geologic map of the study area, the Ten Stone Ranges Structural Complex. The serial cross-sections were used to define the geometry of the Cache Lake Fold, a large fault-bend-fold system that involves a folded thrust fault and complicated subsurface geometry. In addition to this, the sections confirmed that the TSRSC is a transfer zone whereby a series of thrust faults and décollement folds are responsible for much of the displacement and shortening in the Mount Eduni map sheet. The balanced regional cross-section was constructed across a number of key structural elements, in particular the Plateau Fault, a regional structure with a > 250 kilometer strike length and the subject of much debate as to its geometry. In addition to this structure, the cross-section transects the Cache Lake Fold and the Shattered Range Anticline, a regional box shaped anticline that was used for a “depth to detachment” calculation. By examining the regional detachment level estimated from the balanced cross-section and calculating the detachment depth using the Shattered Range Anticline the detachment depth was found to be – 11.3 kilometers below the current erosional level. This study is the first structural analyses of the Mount Eduni map sheet, particularly the Ten Stone Ranges Structural Complex, and has resulted in an estimate of the detachment depth for the area, a shortening estimate of > 7 kilometers across the 50 kilometer line of section and a displacement estimate for the Plateau Thrust of > 20 kilometers.

The High Arctic has been a complex region of collisional and extensional tectonism through the Mesozoic and Cenozoic. Svalbard, the sub-aerial exposure of the northwestern Barents Shelf, is an excellent natural laboratory investigating for High Arctic tectonism. Using apatite and zircon (U-Th)/He low-temperature thermochronometry combined with geological constraints, we resolve Cretaceous through Paleogene time-temperature histories for four regions of the Southwestern Province. Our results indicate a temperature gradient from south to north of ~185°C to >200°C, respectively, as a consequence of sedimentary burial and elevated geothermal gradient ( 45°C/km) from High Arctic Large Igneous Province activity. Late Cretaceous cooling affected all regions during regional exhumation related to initial rifting in the Eurasian Basin. During Eurekan tectonism: 1) our models indicate a heating event (55-47 Ma) characterized by overthrusting and a lack of erosion of the West Spitsbergen Fold-and-Thrust Belt, with Central Basin sediments derived from northern Greenland, followed by 2) a subsequent cooling event (47-34 Ma) corresponding to a shift in tectonic regime from compression to dextral strike-slip kinematics; exhumation of the WSFTB coincided with strikeslip tectonics.

3D geological modelling is becoming an effective tool for communication and development of geological understanding. This is due to increased computer performance and availability of improved geological modelling software. 3D geological modelling technology has reached the stage where it can be implemented in regionally extensive and geologically complex settings, with the ability to achieve geological insight beyond what could otherwise have been gained through 2D investigations alone. Insight includes better constrained fault and horizon topologies, refined fold geometries, improved understanding of tectonic processes, and characterization of deformational events. By integrating field observations, aeromagnetic maps, and 3D modelling techniques in the northern Labrador Trough, a regionally extensive and structurally complex geological environment, regional faults geometries and topological relationships were refined. Additionally, a new fault, the Ujaralialuk Fault, and two shear zones were interpreted. During modelling, several challenges were identified, including higher computational costs for regionally extensive models, sparse 3D constraints, algorithmic limitations related to complex geometries, and the large investment of time and effort required to produce a single model solution. A benefit of this investigation is that new insight was also gained for a greenfields region which may assist future exploration efforts. Developing 3D models in challenging environments allows for better definition of future workflow requirements, algorithm enhancements, and knowledge integration. These are needed to achieve a geologically reasonable modelling standard and gain insight for poorly constrained geological settings.

Applying the anisotropy of magnetic susceptibility to analogue models provides detailed insights into the strain distribution and quantification of deformation within contractional tectonic settings like fold-and-thrust belts (FTBs). Shortening in FTBs is accommodated by layer-parallel shortening, folding, and thrusting. The models in this research reflect the different deformation processes and the resulting magnetic fabric can be attributed to thrusting, folding and layer-parallel shortening. Thrusting develops a magnetic foliation parallel to the thrust surface, whereas folding and penetrative strain develop a magnetic lineation perpendicular to the shorting direction but parallel to the bedding. These fabric types can be observed in the first model of this study, which simulated a FTB shortened above two adjacent décollements with different frictional properties. The different friction coefficients along the décollements have not only an effect on the geometric and kinematic evolution of a FTB, but also on the strain distribution and magnitude of strain within the belt.  The second series of models performed in this study show the development of a thrust imbricate and the strain distribution across a single imbricate in more detail. Three models, with similar setup but different magnitudes of bulk shortening, show strain gradients by gradual changes in principal axes orientations and decrease in degree of anisotropy with decreasing distance to thrusts and kinkzones. These models show that at the beginning of shortening, strain is accommodated mainly by penetrative strain. With further shortening, formation of thrusts and kinkzones overprint the magnetic fabric locally and the degree of anisotropy is decreasing within the deformation zones. At thrusts, an overprint of the magnetic fabric prior deformation towards a magnetic foliation parallel to the thrust surfaces can be observed. A rather complex interplay between thrusting and folding can be analysed in the kinkzones. In general, this thesis outlines the characteristics of magnetic fabric observed in FTBs, relates different types of magnetic fabric to different processes of deformation and provides insights into the strain distribution of FTBs.

No presente trabalho buscou-se compor um quadro geológico-estrutural da Faixa Paraguai meridional e compreender as relações estratigráficas entre os litotipos da Formação Puga e grupos Cuiabá e Corumbá. Foram realizados trabalhos de reconhecimento geológico e perfis geológico-estruturais de detalhe, com análise estrutural e petrográfica, em conjunto com a integração de dados e mapas existentes, análise de imagens de satélite, fotos aéreas e modelos digitais de terreno. A Faixa Paraguai meridional evoluiu como um típico fold-andthrust belt. A evolução geológica do cinturão principia por processos de rifteamento, provavelmente no final do Criogeniano, evoluindo para mar restrito e margem passiva até o final do Ediacarano. A fase rifte é caracterizada pelas formações Puga e Cerradinho. A fase margem passiva está representada pelas formações Bocaina, Tamengo e Guaicurus. Propõe-se que o Grupo Cuiabá na área estudada seja constituído por depósitos marinhos profundos, turbidíticos distais depositados comitantemente aos sedimentos do Grupo Corumbá. O processo colisional responsável pela inversão da bacia com a deformação e metamorfismo associados ocorreu durante o Cambriano, com magmatismo pós-colisional no Cambriano Superior. O estilo estrutural torna-se progressivamente mais complexo de oeste para leste. São observadas até três fases de dobramento coaxiais sobrepostas com eixos subhorizontais de direção N-S. Associam-se a sistemas de falhas de empurrão com deslocamento da capa para oeste. As lineações de estiramento e indicadores cinemáticos observados sugerem que a convergência colisional em direção ao bloco Rio Apa que deu origem à faixa móvel não foi completamente frontal, existindo algum grau de obliquidade, com vetores de convergência em torno de WNWENE. Os micaxistos do Grupo Cuiabá mostram o estilo estrutural mais complexo, com três fases de dobramentos coaxiais e foliações tectônicas mais intensas. Haveria correlação temporal entre S3 gerada nos micaxistos, comumente referidos como Grupo Cuiabá, a leste com a foliação S2 gerada na porção central e a clivagem S1 gerada no limite da área cratônica a oeste, padrão que pode ser explicado pela migração do front deformacional de leste para oeste. É sugestivo que as principais falhas de empurrão coincidam com limites bacinais importantes, onde ocorrem variações de espessura e representatividades das formações basais. No processo de inversão da bacia provavelmente os empurrões reativaram as antigas falhas lístricas principais do estágio rifte. / This work aims to characterize the geological and structural context of the Southern Paraguay Folded Belt, and to understand the stratigraphic relationships between the Puga Formation, Corumbá and Cuiabá groups. Regional geological reconnaissance work and detailed geological-structural field sections were carried out, with petrographic and structural analysis, together with integration of existing data and maps and analysis of satellite images, aerial photos and digital terrain models. The southern Paraguay Belt is a typical fold-andthrust belt. Its geological evolution began with rifting (Puga and Cerradinho formations), probably at the end of Criogenian, and evolved to restricted sea and passive margin (Bocaina, Tamengo and Guaicurus formations) in the late Ediacaran. It is proposed that the Cuiabá Group in the study area consists of distal marine deposits coeval with the Corumbá Group. The collisional process responsible for basin inversion and associated deformation and metamorphism occurred in the Cambrian, with post-collisional magmatism in the Upper Cambrian. The structural style becomes increasingly complex from west to east. Up to three overprinted coaxial folding phases are observed with north / south upright axial planes dipping to east and axes plunging gently to North or South. A system of thrust faults is associated with displacement of the hangwall to the west. Down-dip to oblique and strike-slip stretching lineations are also observed, with kinematic indicators showing movement varying from inverse to sinistral. This suggests that the collisional convergence toward the Rio Apa block which generated the mobile belt was not strictly frontal, but had some degree of obliquity, with convergence vectors around SSW - ENE. The Cuiabá Group mica-schists show the most complex structural style with three superimposed coaxial fold phases and more intense tectonic foliations. It is proposed that there would be time correlation between the S3 foliation in the mica-schists in the easternmost area, with the S2 foliation in the central area and the S1 cleavage at the limit of the cratonic area to the west. This pattern can be explained by the westward migration of the deformational front. It is suggestive that the main thrusts coincide with major basin boundaries, where greater variations in thickness and expression of the basal formations occur. During the basin inversion the thrusts probably reactivated the former main listric faults of the rift stage.

Alkalic porphyry style Au-Cu deposits of the Cadia district are associated with Late-Ordovician monzonite intrusions, which were emplaced during the final phase of Macquarie Arc magmatism at the end of the Benambran Orogeny. N-striking faults, including the curviplanar, northerly striking, moderately west-dipping basement thrust faults of the Cadiangullong system, developed early in the district history. NE-striking faults formed during rifting in the late Silurian. Subsequent E-W directed Siluro- Devonian extension followed by regional E-W shortening during the Devonian Tabberabberan Orogeny dismembered these intrusions, thereby superposing different levels porphyry Au-Cu systems as well as the host stratigraphy. During the late Silurian, the partially exhumed porphyry systems were buried beneath the Waugoola Group sedimentary cover sequence, which is generally preserved in the footwall of the Cadiangullong thrust fault system. The Waugoola Group is a typical rift-sag sequence, deposited initially in local fault-bounded basins which then transitioned to a gradually shallowing marine environment as local topography was overwhelmed. Basin geometry was controlled by pre-existing basement structures, which were subsequently inverted during the Devonian Tabberabberan Orogeny, offsetting the unconformity by up to 300m vertically. In the Waugoola Group cover, this shortening was accommodated via a complex network of minor detachments that strike parallel to major underlying basement faults. For this reason, faults and folds measured at the surface in the sedimentary cover can be used as a predictive tool to infer basement structures at depth.

Alkalic porphyry style Au-Cu deposits of the Cadia district are associated with Late-Ordovician monzonite intrusions, which were emplaced during the final phase of Macquarie Arc magmatism at the end of the Benambran Orogeny. N-striking faults, including the curviplanar, northerly striking, moderately west-dipping basement thrust faults of the Cadiangullong system, developed early in the district history. NE-striking faults formed during rifting in the late Silurian. Subsequent E-W directed Siluro- Devonian extension followed by regional E-W shortening during the Devonian Tabberabberan Orogeny dismembered these intrusions, thereby superposing different levels porphyry Au-Cu systems as well as the host stratigraphy. During the late Silurian, the partially exhumed porphyry systems were buried beneath the Waugoola Group sedimentary cover sequence, which is generally preserved in the footwall of the Cadiangullong thrust fault system. The Waugoola Group is a typical rift-sag sequence, deposited initially in local fault-bounded basins which then transitioned to a gradually shallowing marine environment as local topography was overwhelmed. Basin geometry was controlled by pre-existing basement structures, which were subsequently inverted during the Devonian Tabberabberan Orogeny, offsetting the unconformity by up to 300m vertically. In the Waugoola Group cover, this shortening was accommodated via a complex network of minor detachments that strike parallel to major underlying basement faults. For this reason, faults and folds measured at the surface in the sedimentary cover can be used as a predictive tool to infer basement structures at depth.