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Halocinese e tectônica de rafts na bacia emersa de Benguela (Angola): dados de campo, modelagem física e restauração estrutural / Rafts and salt tectonics in the onshore Benguela basin (Angola): field data, sand box modeling and structural restorationsGabriel Macedo de Almeida e Castro 14 February 2014 (has links)
Este trabalho foi feito com dados de campo da Bacia de Benguela, na costa sul de Angola. Nesta área aflora uma plataforma carbonática de idade albiana, análoga às formações produtoras de petróleo de mesma idade na Bacia de Campos. Duas unidades principais compõem a seção albiana na área: uma unidade inferior caracterizada por carbonatos de águas rasas com intercalações de conglomerados e arenitos na base, totalizando 300 m de espessura total, e uma unidade superior formada por sedimentos carbonáticos de águas mais profundas com espessura de 100 m. Esta seção se apresenta em dois domínios estruturais. O norte é caracterizado por uma plataforma de cerca de 5 km de largura, 35 km de comprimento na direção NE e que se encontra próxima ao embasamento. No domínio sul, essa plataforma se apresenta em fragmentos de menos de 10 km de comprimento por até 5 km de largura, alguns deles afastados do embasamento. Dado que há evaporitos sob essa plataforma, fez-se este trabalho com o objetivo de se avaliar a influência da tectônica salífera na estruturação das rochas albianas. A utilização de imagens de satélite de domínio público permitiu a extrapolação dos dados pontuais e a construção de perfis topográficos que possibilitaram a montagem das seções geológicas. Os dados de campo indicam que a estruturação na parte norte, onde há menos sal, é influenciada pelas estruturas locais do embasamento. Já na parte sul, onde a espessura de sal é maior, a deformação é descolada das estruturas do embasamento. Foi feita uma seção geológica em cada domínio e a restauração dessas duas seções mostrou que a unidade albiana na parte sul sofreu uma distensão de 1,25 (125%) e a de norte se distendeu em 1,05 (105%). Essa diferença foi causada por uma maior espessura original de sal na parte sul, que fez com que a cobertura albiana se distendesse mais em consequência da fluência do sal mergulho abaixo, em resposta ao basculamento da bacia em direção a offshore. A intensidade da deformação na parte sul foi tal que os blocos falhados perderam os contatos entre si, formando rafts. Este efeito foi reproduzido em modelos físicos, indicando que a variação na espessura original de sal tem grande influência na estruturação das rochas que o cobrem. As variações de espessura de sal são controladas por zonas de transferência do embasamento e estas mesmas estruturas controlam os limites dos blocos que sofrem soerguimento diferencial no Cenozoico. / The present work was done with field data from Benguela Basin, which is located in the southern coast of Angola. At this site, an albian carbonatic platform, analogous to the hydrocarbon productive formations of the same age in Campos Basin, outcrops near the coast line , in the surroundings of the city of Benguela. Two major units are recognized among this section: The lower one is characterized by shallow water carbonates with sandstones and conglomerates interlayered at its basal levels, and a total thickness of 300 m. The upper section is composed of deep waters carbonate rocks in a 100 m thick package. This section occurs in two structural domains. The northern domain forms a 5 km wide and 35 km long platform elongated in the NE direction and close to the basement to the east. The southern part is represented by less than 10 km long and up to 5 km wide fragments, some of them displaced from the basement. Considering that evaporates underlie this platform, the main objective of this work is to investigate the influence of salt tectonics on the deformation of the albian rocks. The use of satellite images of public domain allowed the extrapolation of punctual information as well as the construction of the elevation profiles, utilized for the elaboration of the geologic sections. The field data indicate that the structuration at the northern domain, where there is less salt, is influenced by the basement structures. On the other hand, at the southern region, where the evaporitic section is thicker, the deformation is detached from the basement. One geologic section was constructed for each domain and their restorations indicated that the southern part of the platform was affected by an extension of 1,25 (125%) and that the extension at the northern part was 1,05 (105%). This variation is due to a thicker salt layer under the southern part, which conducted the albian package to extend more intensively in consequence of the downdip salt flow, when the basin was tilted toward the ocean. At this region extension was so intense that the faulted blocks lost contact with each other, forming the so called rafts. This effect was simulated in sand box models which indicated that the salt thickness plays a major role in the deformation of the overburden rocks. The variations on the original salt thickness was controlled by transfer faults in the basement and these are the same structures that controlled the boundaries of the basement blocks that responded differently to the Cenozoic uplift events
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Halocinese e tectônica de rafts na bacia emersa de Benguela (Angola): dados de campo, modelagem física e restauração estrutural / Rafts and salt tectonics in the onshore Benguela basin (Angola): field data, sand box modeling and structural restorationsGabriel Macedo de Almeida e Castro 14 February 2014 (has links)
Este trabalho foi feito com dados de campo da Bacia de Benguela, na costa sul de Angola. Nesta área aflora uma plataforma carbonática de idade albiana, análoga às formações produtoras de petróleo de mesma idade na Bacia de Campos. Duas unidades principais compõem a seção albiana na área: uma unidade inferior caracterizada por carbonatos de águas rasas com intercalações de conglomerados e arenitos na base, totalizando 300 m de espessura total, e uma unidade superior formada por sedimentos carbonáticos de águas mais profundas com espessura de 100 m. Esta seção se apresenta em dois domínios estruturais. O norte é caracterizado por uma plataforma de cerca de 5 km de largura, 35 km de comprimento na direção NE e que se encontra próxima ao embasamento. No domínio sul, essa plataforma se apresenta em fragmentos de menos de 10 km de comprimento por até 5 km de largura, alguns deles afastados do embasamento. Dado que há evaporitos sob essa plataforma, fez-se este trabalho com o objetivo de se avaliar a influência da tectônica salífera na estruturação das rochas albianas. A utilização de imagens de satélite de domínio público permitiu a extrapolação dos dados pontuais e a construção de perfis topográficos que possibilitaram a montagem das seções geológicas. Os dados de campo indicam que a estruturação na parte norte, onde há menos sal, é influenciada pelas estruturas locais do embasamento. Já na parte sul, onde a espessura de sal é maior, a deformação é descolada das estruturas do embasamento. Foi feita uma seção geológica em cada domínio e a restauração dessas duas seções mostrou que a unidade albiana na parte sul sofreu uma distensão de 1,25 (125%) e a de norte se distendeu em 1,05 (105%). Essa diferença foi causada por uma maior espessura original de sal na parte sul, que fez com que a cobertura albiana se distendesse mais em consequência da fluência do sal mergulho abaixo, em resposta ao basculamento da bacia em direção a offshore. A intensidade da deformação na parte sul foi tal que os blocos falhados perderam os contatos entre si, formando rafts. Este efeito foi reproduzido em modelos físicos, indicando que a variação na espessura original de sal tem grande influência na estruturação das rochas que o cobrem. As variações de espessura de sal são controladas por zonas de transferência do embasamento e estas mesmas estruturas controlam os limites dos blocos que sofrem soerguimento diferencial no Cenozoico. / The present work was done with field data from Benguela Basin, which is located in the southern coast of Angola. At this site, an albian carbonatic platform, analogous to the hydrocarbon productive formations of the same age in Campos Basin, outcrops near the coast line , in the surroundings of the city of Benguela. Two major units are recognized among this section: The lower one is characterized by shallow water carbonates with sandstones and conglomerates interlayered at its basal levels, and a total thickness of 300 m. The upper section is composed of deep waters carbonate rocks in a 100 m thick package. This section occurs in two structural domains. The northern domain forms a 5 km wide and 35 km long platform elongated in the NE direction and close to the basement to the east. The southern part is represented by less than 10 km long and up to 5 km wide fragments, some of them displaced from the basement. Considering that evaporates underlie this platform, the main objective of this work is to investigate the influence of salt tectonics on the deformation of the albian rocks. The use of satellite images of public domain allowed the extrapolation of punctual information as well as the construction of the elevation profiles, utilized for the elaboration of the geologic sections. The field data indicate that the structuration at the northern domain, where there is less salt, is influenced by the basement structures. On the other hand, at the southern region, where the evaporitic section is thicker, the deformation is detached from the basement. One geologic section was constructed for each domain and their restorations indicated that the southern part of the platform was affected by an extension of 1,25 (125%) and that the extension at the northern part was 1,05 (105%). This variation is due to a thicker salt layer under the southern part, which conducted the albian package to extend more intensively in consequence of the downdip salt flow, when the basin was tilted toward the ocean. At this region extension was so intense that the faulted blocks lost contact with each other, forming the so called rafts. This effect was simulated in sand box models which indicated that the salt thickness plays a major role in the deformation of the overburden rocks. The variations on the original salt thickness was controlled by transfer faults in the basement and these are the same structures that controlled the boundaries of the basement blocks that responded differently to the Cenozoic uplift events
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Interaction entre la tectonique salifère et la sédimentation dans des mini-bassins : Exemple de l’Oligo-Miocène du bassin de Sivas, Turquie / Interaction between salt tectonic and sedimentation within salt-related mini-basins : the case of the Oligo-Miocene formations in the Sivas Basin, TurkeyRibes, Charlotte 11 December 2015 (has links)
L’objectif de cette thèse est d’analyser l’évolution d’une province à mini-bassins salifères, en s’appuyant sur l’étude des variations spatiales et temporelles de faciès, d’épaisseurs ainsi que des géométries développées lors du fluage des évaporites. L’exemple naturel investigué est le bassin de Sivas, situé sur le Plateau central Anatolien en Turquie. Ce bassin d’avant-pays enregistre à l’Oligo-Miocène la formation de nombreux mini-bassins secondaires au-dessus d’un niveau d’évaporites allochtones. A partir d’une cartographie et d’une description détaillées des séries sédimentaires accumulées dans les mini-bassins de Sivas, nous avons pu identifier trois ensembles tectono-sédimentaires cohérents :• la formation Karayün (Oligocène moyen à supérieur), constituée de dépôts de playa-lake, fluviatile en tresse et fluvio-lacustre, interprétée comme proche d’un système fluviatile en distributaires ;• la formation Karacaören (Oligocène supérieur, Miocène inférieur), interprétée comme une série alternante entre une rampe mixte deltaïque et carbonatée, et des dépôts de lagune et de plaine côtière ;• la formation de Benlikaya (Miocène), constituée de dépôts de cônes alluviaux, fluviatiles en tresse et playa-lake, interprétée également comme proche d’un système fluviatile en distributaires.Malgré de nombreuses variations de l’épaisseur et de la succession sédimentaire inter- et intra-bassins, des unités stratigraphiques équivalentes ont pu être déterminées à partir de l’identification de lignes isochrones marquant des changements de tendances. Nous avons montré alors que le système sédimentaire de chacun des mini-bassins est contrôlé au premier ordre par trois facteurs interdépendants, à savoir :• l’accommodation par halocinèse, provoquant la surrection des diapirs et des murs périphériques lors de la subsidence du mini-bassin. Ce fluage des évaporites produit des variations intra-basinales de faciès et d’épaisseurs, associées à des déformations syn-sédimentaires en bordure de mini-bassins. À plus grande échelle, ces objets salifères produisent une compartimentation inter-bassins des environnements de dépôts.• le taux d’accumulation sédimentaire, qui influence la faciologie et l’architecture stratigraphique des dépôts.• l’accommodation régionale, lié à la flexure du bassin, à l’origine du dépôt de série isopaques pouvant recouvrir les diapirs et finalement masquer l’influence salifère.À ces paramètres communs aux provinces salifères, nous ajoutons, l’influence des contraintes tectoniques compressives qui modifient les rétroactions entres ces facteurs. / The aim of this thesis is to investigate the development of a salt-related mini-basin province, based on spatial and temporal changes in the facies assemblages, stratigraphic architecture and thicknesses, as well as stratal structures related to salt movement. The study area is the Sivas Basin, located in the Central Anatolian Plateau of Turkey, which is a foreland basin that records the formation during the Oligo-Miocene of numerous secondary mini-basins on top of an allochthonous evaporite canopy. Through detailed mapping of the Sivas mini-basin province, we provide a new and comprehensive description of the stratigraphic vertical succession including:• the Karayün Fm (Mid to upper Oligocene), comprising playa-lake, fluvial braided and fluvio-lacustrine deposits, and interpreted as a large distributive fluvial system;• the Karacaören Fm (Up. Oligocene to Low. Miocene), comprising two main sub-environments: mixed deltaic and carbonate ramp, alternating with coastal plain and restricted lagoon;• the Benlikaya Fm (Miocene), comprising alluvial fan, fluvial braided and playa-lake deposits interpreted also as a large distributive fluvial system;Within neighbouring minibasins and despite a similar vertical stratigraphic succession, variations are observed in stratigraphic units of equivalent age within and between minibasins. At the first order, we have defined three factors that dictate the pattern of mini-basin filling:• salt-induced accommodation producing local faciologic and stratigraphic thickness changes, and halokinetic structures along mini-basin borders. At larger scale, salt structures result in a compartmentalization of facies between basins.• The sediment supply rate, which affects facies assemblage and stratigraphic architecture.• Tectonically driven regional accommodation attributed to the foreland flexure, inducing the deposition of relatively isopachous series draping and finally obscuring the salt topography.In addition, these three factors are largely influenced by shortening during the evolution of the Sivas fold-and-thrust-belt.
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Structure, thermicité et évolution géodynamique de la Zone Interne Métamorphique des Pyrénées / Structure, thermicity and geodynamic evolution of the Internal Metamorphic Zone in the PyreneesDucoux, Maxime 20 December 2017 (has links)
La compréhension des processus et des modalités de l’inversion des systèmes extensifs et plus particulièrement les domaines de marges amincies, dans les chaines de collision est un enjeu majeur. La chaîne intracontinentale des Pyrénées constitue un exemple d’inversion de marges passives hyper-amincies, associées à un métamorphisme HT-BP et intégrées dans le prisme orogénique. La première partie de cette étude est centrée sur l’étude de la répartition du métamorphisme HT-BP associé à la phase de rifting et de l’exhumation du manteau lithosphérique. L’apport des données de TRSCM a permis, dans un premier temps, de définir l’enveloppe de la ZIM caractérisée par des températures comprises entre 400 et 630°C à l’échelle de l’ensemble de la chaîne et de montrer qu’il n’existe pas de gradient significatif des températures maximales à cette échelle. Dans un second temps, cette étude a permis de mettre en évidence des sauts de température importants au travers de failles majeures et de distinguer des gradients de températures latéraux à l’échelle des différents bassins constituant la ZIM, en particulier dans l’ouest de la chaîne sur l’exemple de la Nappe de Marbres. Cette partie de l’étude montre également l’importance d’une tectonique salifère antérieure au métamorphisme de HT-BP. La seconde partie de cette étude, concernant la structure de la ZIM met en évidence trois phases de déformation, associées à l’orogenèse pyrénéenne ainsi que le rôle du niveau de décollement des évaporites du Trias supérieur dans l’allochtonie généralisée de la ZIM. De plus, les failles majeures observées dans la ZNP, montrent un mouvement inverse avec une composante décrochante sénestre. L’interprétation de l’ensemble de ces résultats suggère que la ZIM et la ZNP ne forme qu’une seule unité découplée du socle varisque au niveau du Trias supérieur et déplacée par des chevauchements plats issus de l’héritage extensif, lors du début de la convergence. Le mode de déformation est alors de type thin-skinned, puis devient, lors de la collision des deux paléomarges, de type thick-skinned, avec le développement de faille majeures associées à l’exhumation des blocs de socle (Massifs Nord-Pyrénéens) qui ont découpé l’ensemble de la ZIM. / The understanding of the processes and scenarios of the inversion of extensional systems, and more specifically of hyper-extended margins, in collision thrust belts is a major issue. The intracontinental belt of the Pyrenees is an example of inversion of hyper-extended margins, associated with a HT-LP metamorphism and then integrated within the orogenic wedge. The first part of this study is focused on the distribution of the HT-LP metamorphism associated with rifting and the exhumation of lithospheric mantle. A new set of TRSCM data allows the recognition of the geometry of the IMZ, characterized with temperature ranging from 400 to 630°C and shows the absence of a regional gradient at this scale. This study then shows significant temperature gaps across major faults and distinguishes lateral temperature gradients at the scale of the different basins constituting the IMZ, especially in the westernmost part of the belt, in the Nappe des Marbres Basin. This part of the study moreover shows the importance of a salt tectonics prior to the HT-LP metamorphism. The second part shows the existence of three main tectonics phases during the Pyrenean orogeny and the role played by the Late Triassic evaporites as a decollement level in the generalized allochthony of the IMZ. A left-lateral component along the main faults within and along the boundaries of the North Pyrenean Zone (ZNP) is also shown. The interpretation of these observations is that the IMZ and ZNP form a single tectonic unit, decoupled from the Variscan basement by the decollement in the Late Triassic deposits and displaced above shallow-dipping thrust faults inherited from the rifting episode, during the first stages of the convergence. Deformation mode is then thin-skinned and becomes thick-skinned when the two paleomargins collide, with the development of major steeper faults linked with the exhumation of basement blocks (North Pyrenean Massifs) that dissected the IMZ.
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Basement fault influence on the Bicorb-Quesa Salt Wall kinematics, insights from Magnetotelluric and Paleomagnetic techniques on Salt TectonicsRubinat Cabanas, Marc 27 June 2012 (has links)
El text del Capítol 3 ha estat retirat seguint instruccions de l’autor de la tesi, en existir participació d’empreses, existir conveni de confidencialitat o existeix la possibilitat de generar patents / The text of Chapter 3 has been withdrawn on the instructions of the author, as there is participation of undertakings, confidentiality agreement or the ability to generate patent / The Bicorb-Quesa salt wall is located on the external Prebetics, an excellent natural laboratory to observe the diapir evolution because of their excellent outcrops. This area, located on the limit between the Iberian Massif, the Betic Range and the Valencian Trough; preserves the deformation caused by four deformation stages: two extensional and two extensive phases.
The complexity and changing geometry of the salt wall lead us to use different techniques, some of them rarely used on salt tectonics studies, in order to provide significant information on the knowledge of the salt wall kinematics. The Magnetotelluric data shows the wide range of electrical resistivity materials values. This technique allowed us to recognize a basement fault with a vertical throw of 1000 m. which was active during the Triassic to Lower Cretaceous and likewise elucidate about the salt wall shape and the salt location. The Paleomagnetic data provide valuable information about the rotation suffered on the area both the syn-diapiric basins and the diapir, revealing rotation on different areas. This information together with the internal diapir structure and the overburden structure makes possible to interpret the initiation and reactivation of salt wall as driven by thin-skinned contractional deformation of the overburden. These processes were preferentially developed on the top of a pre-existing basement fault. A comprehensive analysis brings into relief the role played by the propagation direction sense of the cover deformation and the dip sense of the basement fault.
This thesis contributes on the scientific knowledge of the salt tectonics, in its kinematics and evolution in different tectonic settings. The salt tectonics is also a geological branch very attractive for the oil industry as it generates one of the most important trap sources. / La presència de materials evaporítics condiciona l’estructura que es desenvoluparà en un àrea ja que les propietats reològiques de les evaporites són molt diferents a les d’altres materials. Especialment la sal, que es deforma plàsticament, és menys densa i més dèbil que la majoria dels materials (Jackson i Talbot, 1986; Jackson i Vendeville, 1994). Aquestes propietats permetran la formació de coixins salins, diapirs salins, parets salines, llengües salines, etc. La generació d’aquestes estructures i el fet de que la sal sigui impermeable propicia la formació de trampes per hidrocarburs i la possibilitat d’emmagatzemar CO2 o altres residus. Aquest fet els hi dóna a les estructures salines interès econòmic i facilita l’avenç científic en la matèria, com mostra la publicació d’articles que han millorat el coneixement d’aquestes estructures a partir dels anys ‘90 (ex. Vendeville i Jackson 1992; Jackson 1995; Letouzey et al. 1995; Ge et al. 1997; Rowan et al. 2003; Stewart 2006; Hudec i Jackson 2007, etc.)
L’efecte causat a una cobertora fràgil, pel moviment de una falla normal de basament sobre la qual tenim un nivell de desenganxament dúctil ha estat ampliament estudiat (Koyi et al. 1993; Nalpas i Brun 1993; Jackson i Vendeville 1994; Vendeville et al. 1995; Stewart i Clark 1999; Withjack i Callaway 2000; Dooley et al. 2003; 2005). També, amb la mateixa disposició de materials fràgils-dúctils, ha estat investigada la inversió de les falles normals de basament durant una etapa compressiva (Letouzey et al. 1995; Stewart i Clark 1999; Krzywiec 2004; Ferrer et al. 2012). Per altra banda, la deformació de pell prima provocada per una època compressiva a sobre de un nivell de desenganxament també ha estat estudiada (ex. Chapple 1978; Davis i Engelder 1985; Coward i Stewart 1995; Sans i Koyi 2001), i amb la mateixa geometria les conseqüències de una compressió en un diapir previ (Vendeville i Nilsen 1995; Canerot et al 2005; Roca et al 2006; Callot et al. 2007; Dooley et al. 2009). Tanmateix, no hi ha cap estudi previ publicat en revistes científiques internacionals que descrigui la deformació per compressió de la pell prima prèviament afectada per una falla de basament. Per tal d’omplir aquest buit, s’ha estudiat la paret salina de Bicorb-Quesa, molt adequada ja que està localitzada a sobre d’una falla de basament, en una zona afectada per compressió amb deformació de pell prima (Roca et al 1996, 2006).
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Analyse multi-échelles des déstabilisations sous-marines de la Marge Ligure : implications sur la répartition spatio-temporelle des facteurs déclenchant [sic] / Multi-scale analysis of submarine landslides on the Ligurian Margin : implication on the spatio-temporal distribution of the triggering factorsHassoun, Virginie 30 September 2014 (has links)
La marge Ligure est une marge passive soumise à une déformation tectonique compressive associée à la tectonique salifère messinienne. La reprise en compression de la marge s’accompagne d’une sismicité modérée récurrente ponctuée d’évènements plus forts. La marge Ligure est le siège d’une sédimentation importante au Plio-Quaternaire. Elle constitue un environnement propice à l’étude des déstabilisations gravitaires. L’objectif principal de ce travail était de décrire et caractériser les principaux mouvements en masse ayant affecté la marge continentale Ligure au cours du Plio-Quaternaire, de localiser les principales zones sujettes aux déstabilisations et d’identifier les facteurs pré-conditionnant et déclenchant les ruptures dans le but de mieux évaluer l’aléa gravitaire. Une large couverture de données bathymétriques, géophysiques et des carottages acquis sur l’ensemble de la marge a permis de réaliser une étude multi-échelles des processus de ruptures gravitaires et des facteurs déclenchant associés. Près de 1500 glissements ont été identifiés. L’étude de leur répartition spatio-temporelle illustre que l’ensemble de la marge a toujours été affectée par des déstabilisations de pente mais que les principales zones de ruptures auraient migré vers l’ouest au cours du Plio-Quaternaire. Les grandes ruptures sous-marines sont préférentiellement associées aux zones de déformation maximale, cette dernière étant contrôlée par la tectonique crustale et/ou la tectonique salifère. Il apparaît que les ruptures résultent plus généralement d’une association de facteurs distincts qui ont participé à fragiliser la stabilité des dépôts de la pente et qui ont pu provoquer leur rupture. / The Ligurian margin is a passive margin characterized by high sedimentation rates during the Plio-Quaternary. It is affected by a compressive tectonic deformation leading to the inversion of the margin, together with a salt tectonic. The present-day moderate seismic activity is punctuated by stronger seismic events. Thus, this margin offers a good natural laboratory to study submarine landslides and their triggering factors. Although the Var Turbidite System has been well investigated over the last 20 years, the morphology and tectonics/sedimentary processes affecting the whole margin remained poorly known. This study aims to describe and to characterize the main types of mass movements, their preferential locations along the Ligurian margin during the Plio-Quaternary and their triggering factors to improve geohazards assessment related to landslides. A dataset including bathymetric and geophysical data and cores allowed to realize a multi-scale study of submarine failures and their associated triggering factors. About 1500 landslides were identified on the margin and in the basin. The study of their spatio-temporal distribution revealed that the margin has always been affected by mass-wasting processes and that the main zones of landsliding migrated westward during the Plio-Quaternary. The largest submarine landslides are preferentially associated with the highest deformation rates and their location is controlled by crustal tectonics and/or salt tectonics. The initiation of failures results from the combination of several factors including the margin deformation, earthquakes, salt tectonics and sediment under-consolidation.
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Géodynamique du bassin de Sivas (Turquie) : de la fermeture d’un domaine océanique à la mise en place d’un avant-pays salifère / Geodynamics of the Sivas basin (Turkey) : from oceanic closure to a salt forelandLegeay, Étienne 13 October 2017 (has links)
L’Anatolie fait partie d’un vaste domaine orogénique qui s’étend des Alpes à l’Himalaya. Les sutures ophiolitiques rencontrées marquent les cicatrices de plusieurs domaines océaniques (branches de la Néotéthys Nord), interdigités entre plusieurs blocs crustaux au cours du Mésozoïque. La fermeture de ces domaines au Crétacé supérieur est accompagnée de la mise en place de bassins tertiaires syn-orogéniques dont fait partie le Bassin de Sivas, limité au nord par le bloc du Kırşehir et au Sud par les Taurides. Une étude structurale de terrain, complétée d’analyses géochimiques, biostratigraphiques et thermochronologiques ainsi que l’étude de 700 km de lignes sismiques 2D inédites, a été menée pour tenter de comprendre (i) le contexte géodynamique régional et (ii) l’architecture tectono-sédimentaire de ce bassin.L’étude des ophiolites présentes le long de la bordure sud du Bassin de Sivas met en évidence des péridotites intensément serpentinisées. La partie supérieure de l’ophiolite présente des brèches et ophicalcites caractéristiques de l’exhumation mantellique, alors que l’analyse géochimique des corps magmatiques révèle un environnement de supra-subduction, daté à circa 90 Ma (U-Pb sur zircon). Ces analyses démontrent la présence d’un domaine océanique embryonnaire entre le Kırşehir et les Taurides, dont la fermeture s’initie le long d’ancienne failles de détachement. L’obduction de la nappe de péridotite et de son mélange frontal sur la marge Nord des Taurides entre le Turonien et le Maastrichtien, permet de former le « socle ophiolitique » commun aux bassins est-anatoliens. L’analyse détaillée de la partie centrale du bassin, en carte et à l’aide de lignes sismiques 2D inédites et de thermochronologie basse température [AFTA et (U-Th)/sur apatite], a permis de proposer un modèle d’évolution cinématique sur la base de coupes équilibrées. La propagation de la déformation vers le Nord, initiée dès l’Eocène inférieur, permet l’isolation progressive du bassin et une forte accumulation d’évaporites à l’Eocène supérieur. Les dépôts de l’Oligo-miocène sont ensuite contrôlés par l’halocinèse, permettant la mise en place de deux générations de mini-bassins salifère, séparés d’une canopée. Les géométries dans le domaine halocinétique, et les variations latérales dans le bassin, montrent le contrôle exercé par (i) le bassin pré-évaporite affleurant le long de la moitié sud du bassin et (ii) l’épaisseur du niveau de sel initial.L’intégration de ces observations à l’échelle régionale met en évidence un contrôle du raccourcissement crustal, dans les Taurides et les bassins tertiaires, lié à la fermeture de la Néotéthys Sud, en générant l’émergence de structures de socles. La collision enregistrée à l’Oligocène supérieur - Miocène lors de l’indentation de la plaque Arabe le long des Taurides est contemporaine de la déformation du Bassin de Sivas et des bassins adjacents. / Anatolia is part of a vast orogenic domain that extends from the Alps to the Himalayas. Numerous ophiolitic sutures defined the remnants of several oceanic domains (Northern and southern Neotethys), between continental fragments formed during Mesozoic time. Oceanic closure during Late Cretaceous is recorded by the establishment of syn-orogenic tertiary basins, including the Sivas Basin bounded to the north by the Kırşehir block and to the south by the Taurides. An extended study based on field and completed by geochemistry, biostratigraphy and thermochronology analyzes and more than 700 km unpublished seismic data, was conducted to resolve (i) the regional geodynamic context and (ii) the tectono-sedimentary architecture of this basin.The ophiolites located along the southern edge of the Sivas Basin are made of serpentinized peridotites. The upper part of the ophiolite present breccias and ophicalcites commonly described as associated to mantle exhumation environment, while the geochemical analysis of the magmatic bodies reveals a supra-subduction environment dated at circa 90 Ma (U-Pb on zircon). These observations are in agreement with an embryonic ocean domain located between the Kırşehir and the Taurides, the closure which was initiated along fossil detachment faults. The obduction of the peridotite nappe and its frontal mélange on the northern margin of the Taurides between the Turonian and the Maastrichtian allows forming the “ophiolitic basement” of the east-anatolian basins.A detailed map and cross-section analysis, supported by 2D seismic lines and low-temperature thermochronology [AFTA and (U-Th) / on apatite], resulted in a kinematic evolution model and the realization of balanced cross-sections. The propagation of the deformation towards the north, initiated in the Lower Eocene, results in the progressive isolation of the basin and a strong accumulation of evaporites during the Upper Eocene. The Oligo-Miocene depocenters were controlled by halokinesis, forming two generations of mini-basins, separated by a salt canopy. The geometries in the halokinetic domain and the lateral variations in the basin show the control exerted by (i) the pre-evaporite basin outcropping along the southern half of the basin and (ii) the thickness of the initial salt level.Integration at the regional scale within the Taurides highlights the propagation of crustal shortening related to the Southern Neotethys closure, which formed linear tectonic basement exhumation. The collision recorded in the Upper Oligocene - Miocene during the indentation of the Arabic plate along the Taurides is contemporaneous to the deformation the Sivas Basin.
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