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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

Banda Forearc Metamorphic Rocks Accreted to the Australian Continental Margin: Detailed Analysis of the Lolotoi Complex of East Timor

Standley, Carl Eldon 29 January 2007 (has links) (PDF)
Petrologic, structural and age investigations of the Lolotoi Complex of East Timor indicate that it is part of a group of thin metamorphic klippen found throughout the region that were detached from the Banda forearc and accreted to the NW Australian continental margin during Late Miocene to Present arc-continent collision. Metamorphic rock types are dominated by (in order of greatest to least abundance), greenschist, graphitic phyllite, quartz-mica schist, amphibolite and pelitic schist. Mineral, whole rock, and trace element geochemical analyses of metabasites indicate that protolith compositions are consistent with tholeiitic basalt and basaltic andesite with mixed MORB and oceanic arc affinities. Metapelitic schist compositions are consistent with mafic to intermediate oceanic to continental arc provenance. Geothermobarometric calculations show peak metamorphic temperatures in pelitic rocks range from 530°C to 610°C for garnet-biotite pairs and peak pressures of 5 to 8 kbar for garnet-aluminosilicate-quartz-plagioclase assemblages. Analyses of amphibole in amphibolites yield temperatures of 550°C to 650°C and pressures of 6 to 7 kbar. Lu-Hf analyses performed on garnet samples from two massifs in East Timor yielded four ages with a mean of 45.36 ± 0.63 Ma, which is interpreted to represent the approximate age of peak metamorphism. Detrital zircons from one amphibolite sample in East Timor yields a bimodal U-Pb age distribution of 560 Ma and 80 Ma, indicating deposition occurred after the 80 Ma closure of the zircon grains. The sequence of deformation as indicated by field measurements is similar to that reported from other klippen throughout the Timor region. Contact relationships with adjacent units indicate that the metamorphic terrane is in thrust contact with underlying Gondwana Sequence rocks. Overlying the metamorphic rocks are Asian affinity volcanic and sedimentary cover units found mostly in normal fault contact on the edges of Lolotoi Complex klippen. Geochemical, age, petrological and structural data imply the Lolotoi Complex formed part of the eastern Great Indonesian arc, which began to collapse in the Eocene, was incorporated into the Banda arc in the Miocene, and accreted to the Austrailian continental margin from Pliocene to Present.
252

Programming tools for intelligent systems

Considine, Breandan 04 1900 (has links)
Les outils de programmation sont des programmes informatiques qui aident les humains à programmer des ordinateurs. Les outils sont de toutes formes et tailles, par exemple les éditeurs, les compilateurs, les débogueurs et les profileurs. Chacun de ces outils facilite une tâche principale dans le flux de travail de programmation qui consomme des ressources cognitives lorsqu’il est effectué manuellement. Dans cette thèse, nous explorons plusieurs outils qui facilitent le processus de construction de systèmes intelligents et qui réduisent l’effort cognitif requis pour concevoir, développer, tester et déployer des systèmes logiciels intelligents. Tout d’abord, nous introduisons un environnement de développement intégré (EDI) pour la programmation d’applications Robot Operating System (ROS), appelé Hatchery (Chapter 2). Deuxièmement, nous décrivons Kotlin∇, un système de langage et de type pour la programmation différenciable, un paradigme émergent dans l’apprentissage automatique (Chapter 3). Troisièmement, nous proposons un nouvel algorithme pour tester automatiquement les programmes différenciables, en nous inspirant des techniques de tests contradictoires et métamorphiques (Chapter 4), et démontrons son efficacité empirique dans le cadre de la régression. Quatrièmement, nous explorons une infrastructure de conteneurs basée sur Docker, qui permet un déploiement reproductible des applications ROS sur la plateforme Duckietown (Chapter 5). Enfin, nous réfléchissons à l’état actuel des outils de programmation pour ces applications et spéculons à quoi pourrait ressembler la programmation de systèmes intelligents à l’avenir (Chapter 6). / Programming tools are computer programs which help humans program computers. Tools come in all shapes and forms, from editors and compilers to debuggers and profilers. Each of these tools facilitates a core task in the programming workflow which consumes cognitive resources when performed manually. In this thesis, we explore several tools that facilitate the process of building intelligent systems, and which reduce the cognitive effort required to design, develop, test and deploy intelligent software systems. First, we introduce an integrated development environment (IDE) for programming Robot Operating System (ROS) applications, called Hatchery (Chapter 2). Second, we describe Kotlin∇, a language and type system for differentiable programming, an emerging paradigm in machine learning (Chapter 3). Third, we propose a new algorithm for automatically testing differentiable programs, drawing inspiration from techniques in adversarial and metamorphic testing (Chapter 4), and demonstrate its empirical efficiency in the regression setting. Fourth, we explore a container infrastructure based on Docker, which enables reproducible deployment of ROS applications on the Duckietown platform (Chapter 5). Finally, we reflect on the current state of programming tools for these applications and speculate what intelligent systems programming might look like in the future (Chapter 6).
253

Structural Investigations of the Italian Trap Allochthon, Redington Pass, Pima County, Arizona

Benson, Gregory Scott January 1981 (has links)
Italian Trap Allochthon is a rare upper-plate exposure of Paleozoic metasedimentary and Precambrian to Tertiary crystalline tectonites in the Santa Catalina-Rincon metamorphic core complex. Elsewhere in the complex, metasedimentary tectonite is usually restricted to an autochthononous position. The internal structures of the allochthon consist of numerous low-angle faults, tear faults, and overturned asymmetric and upright folds. Close association of the low-angle faults and asymmetric folds, and vergence of the folds, indicates that these folds were formed during westward transport along the low-angle faults. The structures of the allochthon are truncated and rotated to the northeast by a listric (?) normal fault. The probable shape of the fault surface, together with the northeastward rotation of the internal structures, suggests translation of the allochthon from the northeast to the southwest. The fact that metasedimentary tectonites are found in upper- plate position indicates that the listric (?) normal faulting post-dates the metamorphism of the Paleozoic and Mesozoic strata. Metamorphism in turn was part of the development of the Santa Catalina-Rincon metamorphic core complex. It is inferred that the Italian Trap Allochthon was emplaced in the final stages of profound regional extension which prevailed during the mid-Tertiary in southern Arizona.
254

Precambrian Geology of the Cottonwood Cliffs Area, Mohave County, Arizona

Beard, Linda Sue January 1985 (has links)
A belt of Early Proterozoic rocks crops out in the Cottonwood Cliffs area, northwest Arizona. The belt contains an eastern and a western assemblage separated by the Slate Mountain fault. The western assemblage consists of mafic to felsic metavolcanic rocks, metapelites, and metaconglomerates. The eastern assemblage consists of phyllites, felsic to intermediate metavolcanic rocks, metagraywackes, and metagabbro bodies. The belt is bounded to the east by foliated granodiorite. The Valentine granite intruded the belt on the west and north. Steeply-plunging lineations and fold axes, and northeast-trending vertical foliation dominate the structural fabric. The regional elongation direction is near-vertical, as indicated by mineral and pebble lineations, and is parallel to fold axes. Although only one deformational event is evident, the intensity of that event may have obliterated evidence of any earlier deformation. Tertiary basalts and the Peach Springs Tuff locally overly the metamorphic rocks. Cenozoic normal faults in the area are mostly of minor displacement.
255

Cenozoic tectonic deformation, thermochronology and exhumation of the Diancang Shan metamorphic massif along Ailao Shan-Red River shear zone, southeastern Tibet, China / Känozoischen tektonischen Deformationen, Thermochronologie und Exhumierung der Diancang Shan metamorphen Massiv entlang Ailao Shan-Red River Scherzone, Südost-Tibet, China

Cao, Shuyun 03 November 2010 (has links)
No description available.
256

Petrogenesis of I- and S-type Granites in the Cape River - Lolworth area, northeastern Queensland - Their contribution to an understanding of the Early Palaeozoic Geological History of northeastern Queensland

Hutton, Laurie James January 2004 (has links)
The geological history of the Early Palaeozoic in eastern Australia is not known precisely. The eastern margin of the outcropping Precambrian Craton 'Tasman Line' is poorly understood. The Thomson Orogen, which underlies much of eastern Queensland, lies to the east of the Tasman Line. Basement to the Tasman Orogenic Zone is poorly understood, but knowledge of this basement is critical to our understanding to the processes that formed the eastern margin of the Precambrian craton. The Lolworth-Ravenswood Province lies to the east of the Tasman Line in northeast Queensland. A study of basement terranes in the Lolworth-Ravenswood Province will therefore provide some insights as to the nature of crust beneath this area, and therefore to the basement to the Thomson Orogen. The Fat Hen Creek Complex comprises para-authchthonous bodies of granitoid within middle to upper amphibolite facies metamorphic rocks. Data contained herein demonstrate that the composition and geochemistry of the granitoid are compatible with the generation of the granitoid by partial anatexis of the metamorphic rocks that are part of the Cape River Metamorphics. Temperature and pressure of anatexis is determined to be between 800-850OC and 5-9kb. Under these conditions, experimental data indicate that meta-pelite and meta-greywacke will produce between 5-10% melt coexisting with biotite, cordierite, garnet and plagioclase. The mineralogy of the granitoid bodies in the Fat Hen Creek Complex is consistent with partial anatexis of meta-greywacke at these temperatures and pressures. 5-10% melt is generally insufficient to allow efficient separation of melt and restite. The granitoids of the Fat Hen Creek Complex are interpreted as being a closed system with melt generated during high-grade metamorphism not separating from the residium. U/Pb dating of zircon from the Fat Hen Creek Complex indicate two distinct periods of zircon growth. The older episode occurred during the Late Cambrian to Early Ordovician. A second episode is dated as Middle Ordovician. This younger age coincides with the onset of regional compression, and may be related to exhumation of a mid-crustal layer during thrusting. The Lolworth Batholith is one of three granite batholiths in the Lolworth-Ravenswood Province. It comprises mainly muscovite-biotite granite, with smaller areas of hornblende-biotite granite to granodiorite. Sills and dykes of muscovite and garnet-muscovite leucogranite extensively intrude both of these types. The hornblende-biotite granite to granodiorite is metaluminous, with petrographic and geochemical characteristics similar to the adjacent Ravenswood Batholith. U-Pb SHRIMP ages also overlap with those from the Ravenswood Batholith. ENd(tc) values of ~-3 suggest a significant crustal contribution in the magma. Zircon populations determined using the SHRIMP suggest some inheritance from a Neoproterozoic source. The two-mica granites make up over 80% of the batholith and show little variation throughout. Aluminium Saturation indices range dominantly from 1-1.1, in keeping with the muscovite-bearing nature of the granites. U-Pb ages are significantly younger than the hornblende-biotite granitoids. ENd(tc) is ~-10, suggesting a greater role for crustal material in these granites than in the hornblende-bearing varieties. Previously, these granites were interpreted as S-types, mainly on the basis of the presence of muscovite. Low Na/Ca and Na greater than K are both considered as indicators of source compositions and both are characteristic of a mafic igneous rather than a meta-sedimentary source. Anatexis of mafic igneous rocks at temperatures less than~1000OC are found experimentally to produce peraluminous melts similar to those which produced the two-mica granites. The third major rock-type in the Lolworth Batholith is muscovite leucogranite, which occurs as sills and dykes intruding older granites and basement. The age of the leucogranite was not determined, but it has sharp contacts with the two-mica granite suggesting that the latter had cooled prior to intrusion of the former. The leucogranite is strongly peraluminous and is deemed to have been derived from anatexis of a supra-crustal (meta-sedimentary) source. The batholith is therefore deemed to comprise three different elements. The hornblende-biotite granitoids are the western extension of the adjacent Ravenswood Batholith. The two-mica granite and muscovite leucogranite are derived from different sources, but may be part of the same crustal anatexis event. During the Early Palaeozoic, the Lolworth-Ravenswood Province saw the intrusion of three granite batholiths into a basement of Late Neoproterozoic to Cambrian meta-sedimentary rocks. Also, Late Cambrian to Early Ordovician and Middle Ordovician high-grade metamorphism accompanied by partial anatexis is recorded at several sites across northeast Queensland. Although this metamorphism is restricted to these sites, they are widespread across the area suggestive of a widespread metamorphic event at these times. Similar metamorphism is recorded in the Arunta Inlier in Central Australia increasing the possible extent of this event. The geochemistry, isotopic characteristics and zircon populations of granites in the Lolworth-Ravenswood Province are used to characterise their source rocks; and thus the basement to the Province. Precambrian basement is indicated to underlie the entire province. However, the source rocks for the eastern part of the Province (Ravenswood and into the Lolworth Batholiths) are different to source rocks for the western part of the Province. Georgetown-type crust extends eastwards from the outcropping area, extending under the western Lolworth-Ravenswood Province. Late Mesoproterozoic rocks are recorded from the Cape River area adjacent to the Lolworth Batholith. They are also indicated as source-rocks for granites in the Ravenswood Batholith. Rocks of this age are characteristic of Grenvillian-age mobile belts in the United States. Their presence in north Qeensland has implications for the breakup of Rodinia, the Mesoproterozoic-age super continent that broke up during the Neoproterozoic.
257

Synthesis and Control of Reconfigurable mechanisms / Synthèse et commande de mécanismes reconfigurables

Aimedee, Marie Fidèle 10 December 2015 (has links)
Cette thèse aborde principalement trois grands aspects tels que la systématisation et l'analyse structurale, la modélisation géométrique et cinématique et les stratégies de contrôle. La première partie de la thèse est consacrée à l'élaboration d'une approche pour la systématisation des mécanismes reconfigurables selon leurs paramètres structuraux tels que la mobilité, la connectivité, la redondance et l’hyperstatisme. Ces paramètres nous permettent de comprendre les mécanismes et de les systématiser selon leur type de mouvement ; le mécanisme peut être isostatique ou hyperstatique, redondant ou non-redondant, avec ou sans mobilités internes, etc. Afin de résoudre les problèmes pratiques de modélisation, contrôle, simulation et développement du robot, les paramètres structuraux sont nécessaires. Différents types de singularités sont systématisés et analysés en tenant compte de paramètres structuraux. En plus, pour connaître les positions et les orientations relatives des membres du robot, nous avons besoin de calculer le modèle géométrique. Nous utilisons la méthode du Système de Coordonnées Voyageur pour déterminer la position et l'orientation des membres à chaque instant. Pour connaître les vitesses linéaires et angulaires des membres, nous devons formuler les équations cinématiques pour le robot étudié. La partie contrôle est dédiée à l'élaboration de stratégies de génération de trajectoire et de contrôle, sur la base de la redondance d’actionnement. La difficulté dans la commande est de développer une loi de contrôle avancée pour la synchronisation de plusieurs actionneurs afin d'avoir une transition fluide d'un mode d'assemblage à un autre, ceci sans endommager le robot. Le choix des liaisons actionnées joue également un rôle essentiel en garantissant une haute performance et la contrôlabilité du mécanisme au passage par les configurations singulières. Dans cette thèse, nous nous concentrons sur le mécanisme à une seule boucle fermée de type 8-bar afin d’illustrer les développements réalisés dans les trois parties mentionnées ci-dessus. Il a été démontré que ce mécanisme présente une capacité intéressante de reconfiguration. Il dispose de deux degrés de mobilité dans une configuration générale, mais a besoin d'au moins cinq moteurs pour être entièrement contrôlés dans toutes les configurations singulières. / This thesis mainly addresses three major aspects such as systematization and structural analysis, geometric and kinematic formulation and control strategies. The first part of the thesis is dedicated to the development of a systematization approach for reconfigurable mechanisms with respect to their structural parameters such as mobility, connectivity, redundancy and number of overconstraints. These parameters help us to understand the mechanism and to systematize it according to type of motion, whether the mechanism is overconstrained or non-overconstraint, redundant or non-redundant, with/without internal mobilites, etc. To resolve the practical problems of modeling, control, simulation and development of the robot, the structural parameters are required. Various types of singularities are also systematized and analyzed by taking into account the structural parameters. Further to know the relative location of robot links, we need to compute the geometric model. We use Travel Coordinate System method to determine the position and orientation of links at each instant. To find out the linear and angular velocities of links, we need to formulate the kinematic equations for the robot under consideration. The control part is dedicated to the development of trajectory generation and control strategies, based on actuation redundancy. The challenging task is to develop an advanced control law in order to synchronize several actuators to have a smooth transition from one assembly mode to another without causing wear and tear to the robot. Choice of actuated joints also plays a vital role in ensuring high performance and controllability of the mechanism when crossing singular configurations. In this thesis we focus on the 8-bar single loop mechanism to illustrate the developments achieved in the three parts mentioned above. It has been shown that, this mechanism exhibits an interesting capacity to reconfigure. It has two degrees of mobility in a general configuration but needs at least five motors to be fully controlled in all singular configurations.
258

A Re-Os Study of Sulfides from the Bagdad Porphyry Cu-Mo Deposit, Northern Arizona, USA

Barra-Pantoja, Luis Fernando January 2001 (has links)
Use of Re-Os systematics in sulfides from the Bagdad porphyry Cu-Mo deposit provide information on the timing of mineralization and the source of the ore -forming elements. Analyzed samples of pyrite, chalcopyrite and molybdenite mainly from the quartz monzonite and porphyritic quartz monzonite units are characterized by a moderate to strong potassic alteration (secondary biotite and K- feldspar). Rhenium concentrations in molybdenite are between 330 and 730 ppm. Two molybdenite samples from the quartz monzonite and porphyritic quartz monzonite provide a Re-Os isotope age of 71.7 ± 0.3 Ma. A third sample from a molybdenite vein in Precambrian rocks yields an age of 75.8 ± 0.4 Ma. These molybdenite ages support previous suggestions of two mineralization episodes in the Bagdad deposit. An early event at 76 Ma and a later episode at 72 Ma. Pyrite Os and Re concentrations range between 0.008-0.016 and 3.9-6.8 ppb, respectively. Chalcopyrite contains a wide range of Os (6 to 91 ppt) and Re (1.7 to 69 ppb) concentrations and variable ¹⁸⁷Os/¹⁸⁸Os ratios that range between 0.13 to 22.27. This variability in the chalcopyrite data may be attributed to different copper sources, one of them the Proterozoic volcanic massive sulfides in the district, or to alteration and remobilization of Re and Os. Analyses from two pyrite samples yield an eight point isochron with an age of 77 ± 15 Ma and an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 2.12. This pyrite Re-Os isochron age is in good agreement with the molybdenite ages. We interpret the highly radiogenic initial 1870s/188Os as an indication that the source of Os and, by inference, the ore-forming elements for the Bagdad deposit, was mainly the crust. This conclusion agrees with previous Pb and Nd isotope studies and supports the notion that a significant part of the metals and magmas have a crustal source.
259

Pétrologie, géochimie et genèse des gisements de tsavorite associés aux gneiss et roches calco-silicatées graphiteux de Lemshuku et Namalulu, Tanzanie / Petrology, geochemistry and genesis of tsavorite deposits associated with graphitic gneiss and calc-silicates rocks from Lemshuku and Namalulu, Tanzania

Feneyrol, Julien 16 February 2012 (has links)
La tsavorite, grossulaire vert à V-Cr-Mn, est contenue dans des gneiss et roches calco-silicatées graphiteux, souvent associés à des marbres dolomitiques, et appartenant à la ceinture métamorphique néoprotérozoïque mozambicaine. La tsavorite se trouve soit dans des nodules ou des veines de quartz (gisements primaires), soit dans des placers (gisements secondaires). L'étude minéralogique des tsavorites propose un nouveau protocole de certification de leur origine géographique, à partir du rapport V/Cr, de la teneur en Mn et du [delta]18 O. L'étude des gisements de Lemshuku et Namalulu en Tanzanie montre que le métamorphisme des protolithes sédimentaires riches en matière organique et évaporites s'est effectué à P = 7,0 ± 0,4 kbar et T = 677 ± 14°C, à 634 ± 22 Ma (datation U-Th-Pb sur monazite). Le bâti métamorphique s'est refroidi vers 500 Ma (datation 40Ar-39Ar sur muscovite). Deux stades de métasomatose sont reliés à la formation de la tsavorite : (i) une métasomatose de diffusion formant les nodules à P = 5,0-7,4 kbar et T = 580-691°C; (ii) une métasomatose calcique d'infiltration contemporaine de la formation des veines de quartz à P = 3,6-4,9 kbar et T = 505-587°C. Ces dernières sont datées in situ par la méthode Sm-Nd à 606 ± 36 Ma. Les évaporites continentales, déposées dans une sabkha de côte marine avec des sédiments silico-calcaires, sont transformées en tsavorite dans le cas des nodules, alors que les sels fondus sont associés à la formation des veines de quartz. Les minéralisations sont contrôlées par la lithostratigraphie et la tectonique / Tsavorite, a (V, Cr, Mn)-bearing green grossular, is hosted by graphitic gneisses or calc-silicates, often asssociated with dolomitic marbles, and belonging to the Metamorphic Neoproterozoic Mozambique Belt. Tsavorite is found either as nodules or in quartz veins (primary deposits), or in placers (secondary deposits). The mineralogical study of tsavorites suggests a new protocol to certificate their geographical origin, based on the V/Cr ratio, Mn content and delta18O. The study of the Lemshuku and Namalulu deposits in Tanzania has shown that the metamorphism of organic matter-rich and evaporites-rich sedimentary protoliths occurred at P = 7.0 ± 0.4 kbar and T = 677 ± 14°C, at 634 ± 22 Ma (U-Th-Pb dating on monazite). The metamorphic series cooled down at around 500 Ma (40Ar-39Ar dating on muscovite). Two metasomatic stages are linked to the formation of tsavorite : (i) diffusion metasomatism forming nodules at P = 5.0-7.4 kbar and T = 580-691°C; (ii) calcitic infiltration metasomatism forming quartz veins at P = 3.6-4.9 kbar and T = 505-587°C. These last have been dated in situ with Sm-Nd dating at 606 ± 36 Ma. Continental evaporites, deposited in a coastal marine sabkha with (Si, Ca)-bearing sediments, transformed into tsavorite in the case of the nodules, while the molten salts are associated with the formation of the quartz veins. The mineralisations are controlled by lithostratigraphy and structure

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