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Streule, Michael. "The structural, metamorphic and magmatic evolution of the Greater Himalayan Sequence and Main Central Thrust, Eastern Nepal Himalaya." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:c7e9c6ba-0bcd-4526-903f-a48d629e0dd9.
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Field observations of the Greater Himalayan Sequence in Eastern Nepal demonstrate a ductile, highly strained package of metamorphic rocks that show extensive evidence of crustal anatexis throughout. These can be distinguished from the Lesser Himalayan sequence below by a distinct reduction in metamorphic grade, an inverted metamorphic sequence and a high strain zone corresponding to the Main Central Thrust. Metamorphic studies are combined with geochronology to demonstrate a protracted period of crustal melting followed by rapid decompression from 18.7 Ma to 15.6 Ma. A metamorphic decompression rate is quantified at c.2mm/yr during this period. This is interpreted to represent exhumation of the Greater Himalayan Sequence by a process of ductile, channelised flow from the mid-crust beneath Tibet. Below a prominent band of kyanite gneiss, previously used to locate the Main Central Thrust, but here mapped within the Greater Himalayan Sequence, partial melting is still exhibited. Here monazites are dated at 10.6 Ma. In the Lesser Himalaya below, allanites record a similar 10.1 Ma event. This implies that following channel flow during the mid-Miocene, the channel widened in the lower-Miocene to incorporate a greater structural thickness. Following these two periods of exhumation and ductile extrusion, separated in time and space, Fission Track studies indicate that much slower, erosion driven exhumation proceeded, at <1 mm/yr. This rate increases slightly in the Pliocene, most likely in response to Northern Hemisphere glaciation; no difference in exhumation is seen across the Greater Himalayan Sequence with respect to the different, earlier, phases of ductile channel flow related exhumation. These results demonstrate the episodic nature of channel flow in the Himalaya and reconcile arguments about the position of the MCT in Eastern Nepal.
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Chambers, Alan Frederick. "Kinematics of the frontal Himalayan thrust belt, Pakistan, and the external western Alps, France." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/11281.
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Asim, Muhammad. "HYDROCHEMICAL CHARACTERIZATION AND NUMERICAL MODELING OF GROUNDWATER FLOW IN A PART OF THE HIMALAYAN FORELAND BASIN." Kent State University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=kent1132262925.
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Kumar, Senthil. "Earthquake size, recurrence and rupture mechanics of large surface-rupture earthquakes along the Himalayan Frontal Thrust of India /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-wwwlib.umi.com.innopac.library.unr.edu/dissertations/fullcit/3209126.
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Thesis (Ph. D.)--University of Nevada, Reno, 2005.<br>"August 2005." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.
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Khanal, Subodha. "Upper crustal shortening and forward modeling of the Himalayan fold-thrust belt along the Budhi-Gandaki river, central Nepal." Thesis, [Tuscaloosa, Ala. : University of Alabama Libraries], 2009. http://purl.lib.ua.edu/2151.
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DeCelles, P. G., B. Carrapa, G. E. Gehrels, T. Chakraborty, and P. Ghosh. "Along-strike continuity of structure, stratigraphy, and kinematic history in the Himalayan thrust belt: The view from Northeastern India." AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/623117.
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The Himalaya consists of thrust sheets tectonically shingled together since similar to 58 Ma as India collided with and slid beneath Asia. Major Himalayan structures, including the South Tibetan Detachment (STD), Main Central Thrust (MCT), Lesser Himalayan Duplex (LHD), Main Boundary Thrust (MBT), and Main Frontal Thrust (MFT), persist along strike from northwestern India to Arunachal Pradesh near the eastern end of the orogenic belt. Previous work suggests significant basement involvement and a kinematic history unique to the Arunachal Himalaya. We present new geologic and geochronologic data to support a regional structural cross section and kinematic restoration of the Arunachal Himalaya. Large Paleoproterozoic orthogneiss bodies (Bomdila Gneiss) previously interpreted as Indian basement have ages of similar to 1774-1810 Ma, approximately 50 Ma younger than Lesser Himalayan strata into which their granitic protoliths intruded. Bomdila Gneiss is therefore part of the Lesser Himalayan cover sequence, and no evidence exists for basement involvement in the Arunachal Himalaya. Minimum shortening in rocks structurally beneath the STD is similar to 421 km. The MCT was active during the early Miocene; STD extension overlapped MCT shortening and continued until approximately 15-12 Ma; and growth of the LHD began similar to 11 Ma, followed by slip along the MBT (post-7.5 Ma) and MFT (post-1 Ma) systems. Earlier thrusting events involved long-distance transport of strong, low-taper thrust sheets, whereas events after 12-10 Ma stacked smaller, weaker thrust sheets into a steeply tapered orogenic wedge dominated by duplexing. A coeval kinematic transition is observed in other Himalayan regions, suggesting that orogenic wedge behavior was controlled by rock strength and erodibility.
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Francsis, Matthew Keegan. "Piezometry and Strain Rate Estimates Along Mid-Crustal Shear Zones." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32170.
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Dynamically recrystallized quartz microstructure and grainsize evolution along mid-crustal shear zones allows for the estimation of tectonic driving stresses and strain rates acting in the mid-crust. Quartz-rich tectonites from three exhumed mid-crustal shear zones, the Main Central Thrust (MCT; Sutlej valley, NW India), South Tibetan Detachment System (STDS; Rongbuk valley, S Tibet), and Moine thrust (NW Scotland), were analyzed. Deformation temperatures estimated from quartz microstructural and petrofabric thermometers indicate steep apparent thermal gradients (80â 420 °C/km) across 0.5â 2.3 km thick sample transects across each shear zone. Quartz recrystallization microstructures evolve from transitional bulging/sub-grain rotation to dominant grain boundary migration at ~ 200 m structural distance as traced away from each shear zone. Optically measured quartz grainsizes increase from ~ 30 μm nearest the shear zones to 120+ μm at the largest structural distances. First-order Zener space analysis across the Moine nappe suggests strong phyllosilicate control on recrystallized quartz grainsize. Recrystallized quartz grainsize piezometry indicates that differential stress levels sharply decrease away from the shear zones from ~ 35 MPa to 10 MPa at ~ 200 m structural distance. Strain rates estimated with quartz dislocation creep flow laws are tectonically reasonable, between 10<sup>-12</sup>—10<sup>-14</sup> s<sup>-1</sup>. Traced towards each shear zone strain rate estimates first decrease one order of magnitude before rapidly increasing one to two orders of magnitude at structural distances of ~ 200 m. This kinked strain rate profile is likely due to the steep apparent thermal gradients and relatively constant differential stress levels at large structural distances.<br>Master of Science
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Robinson, Delores Marie, and Delores Marie Robinson. "Structural and neodymium-isotopic evidence for the tectonic evolution of the Himalayan fold-thrust belt, western Nepal and the northern Tibetan Plateau." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289761.
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The Himalayan fold-thrust belt and Tibetan Plateau are the result of the collision between the Indian and Eurasian continents. This dissertation documents the kinematics and tectonic history of the Himalayan fold-thrust belt of western Nepal and the northern Tibetan Plateau. In the Himalayan fold-thrust belt, the Main Central thrust emplaced a hanging wall flat of Greater Himalayan rock over a footwall flat of Lesser Himalayan rock in Early Miocene time. Subsequent growth of the Lesser Himalayan duplex (LHD) uplifted and rotated the Ramgarh thrust sheet, Main Central thrust, and overlying Greater Himalayan rock to the surface. Thus, growth of the LHD is responsible for the northward dips in the Greater Himalaya. New Nd isotopic data from throughout Nepal indicate that Lesser Himalayan rocks consistently have more negative epsilonNd values than Greater and Tibetan Himalayan rocks. Growth of the LHD is documented in the syntectonic sediments of the Neogene Siwalik Group. At ∼10-11 Ma in central and western Nepal, the epsilonNd values of the Siwalik Group shift toward more negative values which indicate detrital input from rocks in the LHD. Regional mapping in western Nepal and three balanced cross sections provide a three-dimensional view of the fold-thrust belt. These cross sections suggest over 900 km of shortening in upper crustal rock from the Indus suture to the Main Frontal thrust. This suggests a corresponding ∼900 km long wedge of lower crustal rock was consumed by the Himalayan-Tibetan orogen. This wedge may have been inserted under the Tibetan Plateau, helping it obtain its anomalously thick crust. If lower crustal rocks have been inserted under the Tibetan Plateau, the Himalayan collision can account for ∼70% of the overthickened crust. This leaves ∼30% to be accounted for by other mechanisms. The Tula uplift documents shortening along the northern edge of the Tibetan Plateau. The lithic composition of its sandstone, deformation, and erosion of strata suggests that significant regional uplift and thickening occurred since Late Jurassic time and is still occurring. These relationships suggest that the northern Tibetan Plateau region was tectonically active, and undergoing shortening, long before the early Tertiary India-Eurasian collision.
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Vince, Kathryn Jane. "Miocene-aged extension within the main mantle thrust zone, Pakistan Himalaya." Thesis, Kingston University, 1997. http://eprints.kingston.ac.uk/20610/.
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During the early stages of the Himalayan orogeny, rocks of the Kohistan Island Arc were thrust southward onto the Indian Plate along the Main Mantle Thrust (MMT), a N-dipping crustal-scale fault zone developed within the NW Himalaya. During thrusting the basement gneisses and granitic lithologies of the Indian Plate developed a strong south-vergent S-C fabric and, in zones of very high shear strains, were mylonitised. However, the presence of high-grade metamorphic rocks on the footwall and low-grade rocks on the hangingwall of the MMT, coupled with discordances in fission track ages across the MMT, suggest that the fault zone was later reactivated as a zone of extension. Field and laboratory investigations of fault rock samples collected from the Kohistan arc and Indian Plate identify a series of N-dipping, N-side down, ductile to brittle, normal shear fabrics and normal faults that post-date peak metamorphism and all south-vergent thrust fabrics. Considerable amounts of extensional slip may have been accommodated along localised, large-scale normal faults on the MMT hangingwall. Distributed, finite, extensional strains were accommodated on the MMT footwall. On the immediate footwall, N-dipping, ductile, normal shears, defined by very fine-grained cataclastic biotites and syn-tectonic chlorite, displace early Himalayan fabrics. Deeper into the MMT footwall, extension was accommodated along larger, more brittle, N-dipping structures some of which, such as the Banna Shear, are of regional extent. As ductile extensional features all occur within the upper 400m of the footwall, the late-stage extension must either have been partitioned into a very narrow zone immediately below the fault, or the zone of ductile shearing was initially much thicker but has been thinned or cut-out by the later brittle faulting. Fault zone products indicate that extensional deformation occurred during decreasing temperature under greenschist-facies conditions. Differences in fission track ages across the MMT suggest that extension was early Miocene in age, synchronous with that within the main Himalayan chain where it is believed to have been driven by uplift along the Main Central Thrust (MCT). However, there is no obvious MCT analogue within the Pakistan Himalaya. The question thus arises as to whether late orogenic extension is a function solely of relatively shallow level thrusting or a result of isostatic adjustment following overthickening or delamination of the deep crust.
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Hoste, Colomer Roser. "Variations latérales de sismicité le long du méga-chevauchement himalayen au Népal." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEE031/document.
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La sismicité présente le long du méga-chevauchement himalayen, dans la trace du fort séisme de 1505, des variations spatiales qui restaient peu résolues. Nous y avons déployé un réseau sismologique temporaire de 15 stations pour la période 2014-2016, en complément du réseau national. Nous avons effectué une détection automatique Seiscomp3 puis un pointé manuel des séismes enregistrés par le réseau, suivi par une localisation absolue Hypo71 et une relocalisation relative d’essaims HypoDD. Le catalogue résultant compte 2154 évènements dans notre zone d’étude dont les profondeurs (8-16 km) sont bien résolues. La confrontation de la sismicité avec des coupes géologiques équilibrées montre que les séismes se localisent dans le compartiment supérieur à proximité du grand chevauchement himalayen au voisinage de rampes ou contacts suspectés entre écailles de moyen pays. Les variations latérales de structures associées à cette sismicité sont susceptibles de contrôler pour partie les ruptures cosismiques de séismes intermédiaires, qui viennent rompre partiellement le chevauchement, comme l’ont démontré les études du séisme de Mw7.8 de Gorkha-Népal, 2015. La segmentation qui en résulte est une donnée importante dans les études d’aléa sismique<br>The seismicity located along the Himalayan mega-thrust, within the trace of the great M8+ 1505AD earthquake, displays striking spatial variations which remained poorly resolved. In order to better constrain and understand these variations, we deployed a 15-stations temporary seismological network for 2 years (2014-2016) as a complement to the national network. We first processed the data with an automatic detection with Seiscomp3, then a manual picking of earthquakes recorded by the network, followed by a Hypo71 absolute localization and HypoDD relative relocation of clustered events. The resulting catalogue contains 2154 local events, shallow to midcrustal (8 - 16 km). The seismicity presented temporal variations suggesting fluid migrations. The confrontation between the seismicity and the geologic balanced cross-sections shows that most eartbquakes happen within the hangingwall of the Main Himalayan Thrust fault nearby ramps or suspected contacts between lesser Himalayan slivers. The lateral variations of some of the structures associated to this seismicity are likely to partially control the extent of the coseismic ruptures during intermediate earthquakes that break partly the locked fault zone, in a similar way as what was reported after the Mw7.8 2015 Gorkha-Nepal earthquake. Better characterizing the segmentation of such faults is an important input for seismic hazard studies
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Imayama, Takeshi, та 武志 今山. "極東ネパールヒマラヤ泥質片麻岩の形成条件". 名古屋大学年代測定資料研究センター, 2010. http://hdl.handle.net/2237/14740.
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Metcalfe, Richard Paul. "A thermotectonic evolution for the main central thrust and higher Himalaya, western Garhwal, India." Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/35067.
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Subsequent to Lower Eocene (ca. 50Ma) collision of the Indian and Asian plates, continental subduction occurred along the N-dipping Main Central Thrust (MCT) of the Himalaya. In western Garhwal, NW India, upper amphibolite facies Vaikrita Group gneisses of the High Himalayan Slab (HHS) were thrust southwards over unmetamorphosed to greenschist facies Garhwal Group quartzites, carbonates and metabasics of the Lesser Himalaya. In the Bhagirathi valley, the MCT forms a ca. 10km thick shear zone composed of mylonitic Munsiari Group augen gneiss, amphibolite and metasediments. Metamorphic grade increases both northwards and with structural height. The MCT zone is bounded to the N by the Vaikrita roof thrust (VT) and by the Munsiari floor thrust (MT) to the S. The VT is a diffuse high-temperature shear zone recognised through a difference in lithology, metamorphic history, and tectonic style between the Vaikrita and Munsiari Groups. The MT is a relatively discrete fault formed at conditions approaching the brittle-ductile transition. N of the MCT zone, the Jhala Normal Fault (JNF) is a ductile to brittle N-dipping extensional shear zone that was responsible for the downthrow of HHS gneisses and Tethyan sediments in response to gravitational instability of the uplifting orogen. Garnet compositional zoning was produced during growth in both the MCT zone and the lower HHS. In the central and upper HHS it resulted from high-temperature homogenization followed by retrogressive re-equilibration. Diffusion studies suggest rapid cooling of the upper HHS garnets may have been caused by crustal thinning across the JNF. The inverted metamorphic sequence is the cumulative result of polyphase metamoiphism. M1 was a post-collisional Barrovian event of garnet to sillimanite grade restricted to the HHS. M2 was contemporaneous with D2 MCT kinematics and was prograde only in the MCT zone and lower HHS possibly as a result of conductive footwall heating. M3 resulted from nearly isothermal decompression of the upper HHS as a consequence of JNF activation. Thermobarometic transects reveal a significant increase in both P and T across the VT with subsequent decreases accompanying structural height in the HHS. Reliable K-Ar (muscovite) cooling ages from a transect through the MCT zone and HHS are progressively younger towards the S. Ages of ca. 22Ma to ca. 8Ma reflect the piggy-back style deformation sequence; disruptions to the younging sequence are interpreted as localised resetting of ages due to out-of-sequence shearing events. Biotite ages commonly suffered from excess argon and were unreliable. An40Ar/39Ar (hornblende) cooling age suggests rocks of the lower MCT zone were not heated above ca. 500°C since the Precambrian. A ca. 20Ma age dates the last high-temperature motion in the upper MCT zone. The decrease in cooling rate obtained from cooling ages for specific mineral blocking temperatures for the upper MCT zone may be hnked to a return to erosion-controlled denudation after JNF extension.
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Mottram, Catherine Mary. "An integrated metamorphic and isotopic study of crustal extrusion along the Main Central Thrust, Sikkim Himalaya." Thesis, Open University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.664515.
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Mountains form where the Earth's plates collide; during this upheaval rocks are deformed by massive forces. The Himalayan orogen represents the ideal natural laboratory to decode the record of the deformational processes encrypted in the rocks. In the eastern region of Sikkim, a unique series of 'time windows' are exposed by doming of a major ductile fault, revealing the inner workings of one of the major mountain-building structures that accommodated the India-Asia collision. The temporal and thermal evolution of the complex zone of deformation associated with this structure, the Main Central Thrust (MCT), was investigated using a combination of whole rock geochemistry (ENd), geochronology (U-Pb and 4°Arl9Ar), accessory and major phase geochemistry, and pressure-temperature modelling. The results demonstrate that: (1) isotope geochemistry can distinguish rock packages that have been juxtaposed over many hundreds of kilometres in complex ductile shear zones; (2) during prolonged ductile deformation of the MCT zone from ~21-9 Ma there was progressively downwards-penetrating deformation and accretion of colder original footwall material to the hotter hanging wall; (3) the associated zone of inverted Barrovian metamorphism documents a sequence of 'paleo-thrusts' that evolved as the thrust-zone deformed rocks at successively lower pressure and temperature conditions «500 to >650°C and 8 to 10 kbar); (4) during the Miocene thrusting progressed at a rate of ~10 mm yr-1 followed by moderately rapid cooling at a rate of ~50-70°C Ma-1 These findings are consistent with a tectonic model where rocks were accreted to a partially-molten mid-crustal channel of ductilely deforming material along the MCT. This study provides new insight into how deformation is accommodated along major thrust faults during mountain building and has implications for how geological tools such as linked geochronology-geochemistry and P-T modelling are used to aid the interpretation of rock deformation in the cores of evolving mountain belts.
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Hubbard, Mary Syndonia. "Thermobarometry, ⁴⁰A r/³⁹Ar geochronology, and structure of the Main Central Thrust zone and Tibetan Slab, eastern Nepal Himalaya." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/13980.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1988.<br>2 folded maps in pocket. Vita.<br>Includes bibliographical references (leaves 158-167).<br>by Mary Syndonia Hubbard.<br>Ph.D.
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Stephenson, Ben J. "The tectonic and metamorphic evolution of the Main Central Thrust zone and High Himalaya around Kishtwar and Kulu windows, northwest India." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389056.
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Robert, Xavier. "Séquence d'activité des failles et dynamique du prisme himalayen : apports de la thermochronologie et de la modélisation numérique." Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00352596.
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L'influence de l'érosion sur la localisation de la déformation dans une chaîne de montagnes est un phénomène souvent envisagé à la suite de modélisations numériques. Or les données géologiques pertinentes en faveur de cette hypothèse sont encore fort peu nombreuses. Aussi, la mise en évidence d'une évolution temporelle et spatiale de la déformation constitue une observable clef pour tester les relations érosion/localisation de la déformation. Nous testons cet effet, sur un objet géologique soumis à des conditions de déplacements aux limites simples et sur un objet géologique soumis à des conditions climatiques et érosives variables latéralement : le flanc sud de l'Himalaya (située au dessus d'un décollement crustal majeur). Elle est soumise à une convergence continue et de valeur constante depuis au moins une dizaine de millions d'années et sa rhéologie est invariante au cours du temps ; elle est en revanche soumise à un gradient climatique d'est en ouest (transversalement par rapport à la direction de convergence), gradient de plus variable au cours du temps. Nous avons mis en oeuvre des techniques de thermochronologie basse température pour consituer une base de données conséquente, que nous avons utilisée dans des modélisations numériques thermo-cinématiques directes et inverses. Nous montrons que 1) au Népal central,le MHT présente une rampe crustale prononcée, et aucun mécanisme de chevauchement en hors-séquence n'est nécessaire pour expliquer les données, 2) la géométrie du MHT varie d'est en ouest, avec une rampe moins prononcée dans l'est de la chaîne, et 3) les variations latérales en terme de mise en place et de cinétique du MFT sont peu importantes.
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Chalaron, Edouard. "Modélisation numérique et signature géologique des interactions entre tectonique, érosion et sédimentation dans l'avant-pays himalayen." Phd thesis, Université de Grenoble, 1994. http://tel.archives-ouvertes.fr/tel-00723716.
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Les structures chevauchantes frontales d'une chaîne de collision et son bassin d'avant-pays constituent une zone où le déplacement des écailles chevauchantes, l'érosion, la sédimentation et la subsidence du substratum se produisent simultanément. Ces différents phénomènes interfèrent et conduisent à une évolution en régime permanent constituée d'une suite d'exhumations et d'enfouissements des écailles des structures. Des modèles originaux développés en Pascal pour chacun des phénomènes sont couplés dans un algorithme général. En faisant varier la valeur des paramètres géométriques et / ou mécaniques, il est ainsi possible d'étudier et de quantifier l'influence de ces phénomènes sur le développement et l'histoire tectonique des fronts de chaîne de collision. De plus ces modèles fournissent un aperçu des faciès sédimentaires à partir des pentes à l'instant du dépôt des sédiments dans les bassins. En effet, lors d'études expérimentales des systèmes fluviatiles, des faciès corrélés avec des classes de pentes ont été mises en évidence par certains auteurs. Dans une deuxième partie le modèle développé est appliqué à la chaîne des Siwalik, piémont de la chaîne himalayenne. Les Siwalik se comportent comme un prisme tectonique décollé à la base lors d'un raccourcissement imposé à l'arrière et érodé en surface. Classiquement on distingue trois formations dans cette chaîne: les Siwalik Inférieur, Moyen et Supérieur. Les premiers dépôts sont datés autour de 18 Ma. Depuis, les conditions de dépôt sont toujours continentales. Au Népal occidental les sédiments des Siwalik sont affectés de plis, de chevauchements et de structures rétrochevauchantes pouvant être séparés par des bassins intramontagneux (duns) déplacés au toit des écailles chevauchantes. L'analyse de la réflectance de la vitrinite (VR0) montre qu'une érosion intense contemporaine de l'activité tectonique équilibre l'épaississement tectonique et empêche ainsi un enfouissement important des séries sédimentaires. Le Main Boundary Thrust (MBT), montre une composante normale des mouvements récents sur une grande partie de sa longueur. Des données microstructurales échantillonnées le long d'un tronçon du MBT sont utilisées pour calibrer les paramètres mécaniques de la chaîne en la considérant comme un prisme de Coulomb. Ces paramètres sont utilisés dans le modèle numérique décrit précédemment afin de caractériser les séquences d'activation des failles dans le système chevauchant des Siwalik ainsi que la sédimentation syn-tectonique associée. La comparaison entre la distribution de la déformation dans l'avant-pays himalayen et dans le modèle numérique montre que le prisme himalayen est en régime permanent contrôlé par une convergence horizontale et par les phénomènes superficiels et se caractérise par une distribution spatiale et temporelle irrégulière des mouvements des failles dans l'ensemble du prisme. Un traitement par Modèle Numérique de Terrain est ensuite appliqué à deux zones de la chaîne des Siwalik au Népal occidental et permet de comparer les structures prédites avec celles proposées par l'analyse de ces MNT pour expliquer la localisation des virgations des structures et leur relation avec le plan de décollement sous-jacent. Finalement l'analyse de la sédimentation dans les bassins transportés et la comparaison des données au secteur de Nahan Dehra-Dun (Inde occidentale) permet d'apprécier le rôle joué par les paramètres dépendant du temps et permet de mieux cerner l'origine des fluctuations enregistrées dans les sédiments de la zone externe de la chaîne himalayenne. En termes de climatologie et de phénomènes superficiels les schémas d'évolutions proposés par les modèles numériques et appliqués à la chaîne himalayenne tendent à montrer qu'il existe une transition brutale vers -6,5 Ma. Les adaptations nécessaires au rééquilibrage par succession d'amincissements et d'épaississement crustaux de la chaîne himalayenne afin de conserver une évolution en régime permanent sont enregistrées dans les bassins sédimentaires périphériques proches ou distaux.
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Mearce, Trevor. "Along-strike changes in the active tectonic configuration of the northwestern Himalaya: insights from landscape morphology, erosion rates, and river profiles." Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/8892.
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Geodetic models suggest that much of the convergence across the Himalaya (~20 mm yr-1) is taken up on the Main Himalayan Thrust, the main decollement beneath the Himalayan orogenic wedge. In Central Nepal and the majority of Northwest India, several geomorphic, geophysical and seismological datasets indicate that this decollement has a mid-crustal ramp that continues uninterrupted for hundreds of kilometers along strike from Nepal in the east to Uttarakhand in the west. In this study, I use spatial analyses of elevation, relief, channel steepness indices, and basin-wide erosion rates from cosmogenic 10-Be concentrations to outline a potential large-scale change in the active fault configuration between the Main Himalayan Thrust and Main Boundary Thrust near longitude 77°E in the Northwestern Indian Himalaya. The physiography in the areas to the east of 77ºE appears similar to that observed along much of the Himalaya where topographic relief, erosion rates, and river channel steepness (ksn <200) remain relatively low in the areas to the south of a line known as the Physiographic Transition-2. North of the Physiographic Transition-2, these metrics increase sharply within a 30-km zone due to higher rock uplift rates above a mid-crustal ramp on the decollement or an unidentified out-of-sequence thrust fault that soles to the decollement. Either of these models are perceivable with a duplex growing by underplating of the Indian plate into the Himalayan orogenic wedge contributing to higher rock uplift rates north of the Physiographic Transition-2. To the west of 77ºE, however, the landscape morphology indicates the Main Boundary Thrust makes a northward bend coinciding with the along-strike termination of the Physiographic Transition-2 and an arc-perpendicular Bouguer gravity anomaly reflecting a trough on the Indian plate near longitude 77°E. These data suggest that the Main Boundary Thrust merges along strike with the ramp or with an emergent fault soling into the Main Himalayan Thrust at this location, potentially marking a significant change in tectonic configuration along the Himalayan arc.<br>Graduate
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Qayyum, Mazhar. "Crustal shortening and tectonic evolution of the Salt Range in Northwest Himalaya, Pakistan /." 1991. http://hdl.handle.net/1957/9504.
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