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Quantifying strain in analogue models simulating fold-and-thrust belts using magnetic fabric analysisSchöfisch, Thorben January 2021 (has links)
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.
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Análise tectono-estratigráfica da Faixa de dobramento Paraguai meridional na Serra da Bodoquena e depressão do Rio Miranda, MS / Tectonostratigraphic analysis of the southern Paraguay fold belt in Serra da Bodoquena and Rio Miranda depression, MSSa, Fernanda Rostirola de 30 October 2009 (has links)
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.
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Architecture of the Silurian sedimentary cover sequence in the Cadia porphyry Au-Cu district, NSW, Australia : implications for post-mineral deformationWashburn, Malissa 11 1900 (has links)
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.
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Architecture of the Silurian sedimentary cover sequence in the Cadia porphyry Au-Cu district, NSW, Australia : implications for post-mineral deformationWashburn, Malissa 11 1900 (has links)
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.
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"Deformação polifásica e metamorfismo do Grupo Cuiabá na região de Poconé (MT), cinturão de dobras e cavalgamentos Paraguai" / Deformação polifásica e metamorfismo do Grupo Cuiabá na região de Poconé (MT), cinturão de dobras e cavalgamentos ParaguaiVasconcelos, Bruno Rodrigo 28 October 2014 (has links)
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Previous issue date: 2014-10-28 / Vários modelos deformacionais foram propostos para o Cinturão Paraguai diferindo principalmente quanto ao número de fases de deformação, sentido da vergência e estilo tectônico. Feições estruturais apresentadas neste trabalho indicam tectônica dominada por escamas de baixo ângulo de mergulho na fase inicial, seguida por duas fases deformacionais progressivas. A primeira fase de deformação (F1) é caracterizada por clivagem ardosiana (S1), com recristalização de minerais da fácies xisto verde, plano axial de dobras isoclinais recumbentes (D1) de direção NE associadas a zonas de falhamento reverso subhorizontais com movimentação de topo para SE. A segunda fase deformacional (F2) mostra vergência para NW, caracterizada por clivagem de crenulação (S2) plano axial de dobras abertas (D2) do acamamento e foliação S1, localmente associada a falhas reversas. A terceira fase de deformação é caracterizada por falhas e fraturas sub-verticais com direção NW mostrando movimentação sinistral, comumente preenchidas por veios de quartzo. O acervo de estruturas tectônicas e paragênese metamórfica descrita indicam que a deformação mais intensa, em nível crustal mais profundo, alcançou a fácies xisto verde durante F1. Acomodando expressivo encurtamento crustal por meio de dobras recumbente e zonas de cisalhamento de baixo ângulo com movimentação de topo para SE, em regime tectônico do tipo pelicular delgado. A fase F2 teve deformação menos intensa e se comportou de maneira rúptil-dúctil, acomodando discreto encurtamento por meio de dobras normais abertas e falhas inversas subverticais desenvolvidas em nível crustal mais raso, com vergência em direção ao Cráton Amazônico. A terceira fase deformacional (F3) foi menos intensa e acomodou encurtamento na forma de fraturas e falhas sinistrais subverticais, comumente preenchidas por veios de quartzo. / Several deformation models have been proposed for the Paraguay Belt, differing mainly in the number of deformation phases, sense of vergence and tectonic style. Structural features presented in this work indicate tectonic dominated by an initial phase of low dipping thrust sheets, followed by two progressive deformation phases. The first deformation phase (F1) is characterized by a slaty cleavage (S1), axial plane of isoclinal recumbent folds (D1) in the NE direction, with recrystallization of minerals from the greenschist facies, related to horizontal shear zones with top-to-the-SE sense of movement. The second stage shows a NW-vergence, characterized by crenulation cleavage, S0 and S1 axial planes of open folds, locally associated with reverse faults. The third deformation phase is characterized by subvertical faults and fractures in the NW direction showing sinistral movement, commonly filled by quartz veins. The collection of tectonic structures and metamorphic paragenesis described indicate that the most intense deformation, at deeper crustal level, reached the greenschist facies during F1. Accommodating significant crustal shortening through isoclinal recumbent folds and low-angle shear zones showing top-to-the SE sense of movement during a thin-skinned tectonic regime. The phase F2 showed more subtle deformation, with more competent rock types developing brittle behavior and less competent rock types developing ductile behavior, by accommodating slight shortening through normal open folds and subvertical reverse faults nucleated in shallower crustal level with vergence towards the Amazonian Craton. The third phase was less intense and shortening is accommodated in the form of fractures and subvertical sinistral faults, commonly filled by quartz veins.
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Análise tectono-estratigráfica da Faixa de dobramento Paraguai meridional na Serra da Bodoquena e depressão do Rio Miranda, MS / Tectonostratigraphic analysis of the southern Paraguay fold belt in Serra da Bodoquena and Rio Miranda depression, MSFernanda Rostirola de Sa 30 October 2009 (has links)
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.
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Architecture of the Silurian sedimentary cover sequence in the Cadia porphyry Au-Cu district, NSW, Australia : implications for post-mineral deformationWashburn, Malissa 11 1900 (has links)
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. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
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Sandbox modelling of forekink and wedge development in a fold and thrust belt / Sandbox-modellering av veck och kilutveckling i en bergskedjaDougherty, Eira Kaya January 2024 (has links)
In nature, rock masses are not static, but constantly changing with erosion, metamorphosis, tectonics and more. Rocks that bend and buckle can be seen almost as nature's origami, being folded into new shapes and structures. During shortening of a sequence of sedimentary layers, they fold and/or thrust to accommodate the convergence. Folds initiate as kinks which may evolve into thrusts. These folds and thrusts form a wedge which grows in height and length with continued convergence. This study examines the sequence of formation of kinking in fold and thrust belts, specifically the development of forekinks from thrusting and the evolution of the wedge. This was done through geometric analysis of images taken of an analogue sandbox model, run in 2011, which consisted of horizontal layers shortened from one end to 25% bulk convergence above a rigid basement. In nature, such wedges are found as accretionary prisms in convergence zones and as fold and thrust belts on either side of an orogen. By simulating the creation of these wedges and kinks with controlled parameters, it is possible to gain an understanding of the mechanical processes involved in their creation, which allows for a better understanding of these processes in nature. This study is mainly based on measurements of separation created by kinking, dip of the kinks at different levels, and the dimensions of the wedge, in addition to other geometric features. The results showed clear trends for the evolution of these geometric features with progressive model shortening. Results show that, forekinks become inactive when a new kink develops in its foreland. The amount of separation within a kink is dependent on how soon a new kink is developed in front of it and the throw (vertical component) is generally larger than the heave (horizontal component). Dip of a forekink steepens as the forekink cumulatively rotates backwards by the creation of new forekinks in front of it. Evolution of the forekinks has a direct impact on wedge development. Wedge length is larger than height and as the shortened layers are compacted, the dimensions of the wedge increase at different rates. Generally the results of this study are in agreement with previous research conducted within the subject. If rock folding is nature’s origami, then the study of these processes can allow us to understand how fold and thrust belts develop, just as studying how a piece of paper folds, can show us how a napkin can transform into a swan. / I naturen är bergmassor inte statiska utan förändras ständigt av erosion, metamorfos, tektonik med mera. Berg som böjs och bänds kan nästan ses som naturens origami; veckandes till nya former och strukturer. Under förkortning av en sekvens sedimentära lager viker de sig och/eller förkastas för att tillgodose konvergensen. Ett veck i ett lager kan så småningom utvecklas till en förkastning. Dessa veck och förkastningar bildar en kil som växer både på höjden och längden med fortsatt konvergens. Denna studie undersöker veckbildning i bergskedjor, specifikt utvecklingen av framåtvända veck och kilens utveckling. Detta gjordes genom geometrisk analys av bilder tagna av ett försök utfört i en analog Sandbox-modell (gjort 2011) som bestod av horisontella lager förkortade från ena änden till 25% bulk-förkortning ovanför en fast bas. Kilar såsom de som ses i modellen hittas i naturen som accretionära prismor i konvergenszoner och på vardera sida om bergskedjor. Genom att simulera skapandet av dessa kilar och veck i en kontrollerad miljö är det möjligt att skapa sig en förståelse för de mekaniska processer som är involverade i dess skapande, vilket möjliggör en bättre förståelse av dessa processer i naturen. Denna studie är huvudsakligen baserad på mätning av separation skapad av veckning, veckens stupning vid olika djup och kilens dimensioner, tillsammans med andra geometriska egenskaper. Resultaten visade tydliga trender för utvecklingen av dessa geometriska egenskaper i samband med att modellen förkortades. Resultaten visar att framåtvända veck blir inaktiva när ett nytt veck utvecklas framför den. Mängden separation inom ett veck beror på hur snart det nya vecket utvecklas framför den och kast (vertikal komponent) är i allmänhet större än hiv (horisontell komponent). Stupning av ett veck blir brantare när vecket kumulativt roterar bakåt genom att det skapas nya veck framför den. Utvecklingen av vecken har en direkt inverkan på kilens utveckling. Kilen är längre än den är hög och då de förkortade lagren komprimeras växer kilens dimensioner i olika takt. Överlag överensstämmer resultaten av denna studie med tidigare forskning inom ämnet. Om veckandet av bergmassor är naturens origami, kan studerandet av dessa processer möjliggöra för oss att förstå hur bergskedjor utvecklas, precis som att studerandet av hur ett papper viker sig, kan visa oss hur en servett kan förvandlas till en svan.
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In-situ stress analysis and fracture characterization in oil reservoirs with complex geological settings: A multi-methodological approach in the Zagros fold and thrust belt / 複雑な地質条件を有する石油貯留層における原位置応力とフラクチャーの総合解析:ザクロス褶曲衝上断層帯におけるマルチ手法の展開Nazir, Mafakheri Bashmagh 25 March 2024 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第25259号 / 工博第5218号 / 新制||工||1995(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 林 為人, 教授 村田 澄彦, 教授 福山 英一 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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Impact du mode de propagation des fronts orogéniques sur la géométrie, la localisation et la chronologie de la déformation : Cas du Bassin de Neuquén, (Argentine) / Geometry, localization and timing of deformation during orogenic front propagation : a case study from the Neuquén basin (Argentina)Matthieu, Branellec 12 December 2014 (has links)
Cette thèse traite de l’enregistrement de la déformation, à différentes échelles de temps et d’espace dans la chaîne plissée de Malargüe et le bloc de San Rafael, situés dans la partie septentrionale du bassin de Neuquén en Argentine. La première partie du travail comprend une analyse de la déformation finie (chaîne de Malargüe) et de la déformation active (bloc de San Rafael) à l’échelle macroscopique. De manière générale, les coupes structurales régionales proposées mettent clairement en évidence le rôle l’héritage structural lié aux structures générées lors de l’ouverture du bassin au Jurassique. Nous montrons également que les mécanismes de soulèvement actuels du bloc de San Rafael à l’est reprennent les modalités de la déformation d’âge Miocène dans la chaîne. Contrairement au mode de structuration des prismes critiques classiques caractérisés par la localisation de la déformation le long d’un niveau de décollement, la structuration de la chaîne est ici issue d’une déformation distribuée plus largement dans la lithosphère. A l’échelle de l’endommagement mesoscopique, la fracturation régionale nous a permis d’enregistrer les différents champs de contraintes régionaux liés aux phases de raccourcissement depuis le domaine pré-plissement jusqu’à la phase syn-plissement. Ces différentes phases sont en accord avec la cinématique de la convergence de la plaque Nazca depuis le Crétacé supérieur. A l’échelle microscopique, l’analyse des propriétés de susceptibilité magnétique des roches met en évidence, d’une part, une compartimentalisation de la déformation à l’échelle de la matrice liée à l’héritage structural extensif. D’autre part, la distribution spatiale de cet endommagement ne démontre pas l’existence de gradient clair des fabriques magnétiques depuis l’avant-pays vers les zones internes ce qui confirme le caractère atypique du système Andin à la latitude de 35°S. Ce dernier étant principalement contrôlé par une déformation distribuée, liée à l’héritage structural et singulièrement différente de celle attendu dans le cadre de la théorie du prisme critique. / This PhD project deals with multiscale record of the tectonic signal in the Malargüe fold-and-thrust-belt (MFTB) located in the northern part of the Neuquén basin (Argentina). The first results presented rely on the study of the macroscopic finite strain in the fold-belt and the characterization of the active deformation of the San Rafael Block uplift. The cross-sections we produce show that structural inheritance related to the Jurassic extension is the main parameter controlling the belt structure. In addition we proposed that the building mechanisms that controlled the MFTB evolution by Miocene times are the same than those triggering the present day San Rafael block uplift. The second part of this work is dedicated to mesoscopic strain pattern analysis recorded by fracture networks. Throughout the MFTB, we are able to describe the occurrence of four main fractures sets emplaced in several stress regime that are linked (1) to the inheritance and (2) to the well-known compression phases from pre-folding to syn-folding settings. Finally the third part of this work describes the microscopic damage recorded by the anisotropy of magnetic susceptibility method. We mainly evidence that there is no clear gradient of magnetic fabrics from foreland to hinterland and that deformation is compartmentalized by structural inheritance. This atypical pattern of magnetic fabrics succession reveals that the matrix damage is governed by the same strain distribution as those observed at macroscopic scale thus providing a supplementary argument to consider the Andean system at these latitudes as singularly different from a classical Coulomb wedge.
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