Dissertations / Theses on the topic 'Marine fans'

T he casing treatment technique for the axial fan has never been more significant since its potential applications were recognized in gas turbines, tunnel ventilation and many other industrial applications where the axial fan would benefit from the casing treatment. In the last two decades experimental investigations were carried out at Cranfield University to examine the influence of recess casing treatment on stall margin, operating efficiency and flow field of a low-speed axial flow fan. They showed more than 50% improvement in the stall margin with a negligible loss in the efficiency. However, a little work has been done on the numerical simulation of casing treatments due to its complexities, even though in recent years computational fluid dynamics [CFD] analysis has been very active in the prediction of various phenomena in turbomachinery. This work presents numerical investigation of flow in a single axial-flow fan with and without recess casing treatment. It involves the detailed effect of the recess casing on stall margin improvement as well as its influence on global performance parameters. The project offers a contribution to the understanding of the physical processes occurring when approaching stall and the working mechanism by which recess casing treatments improve stall margin. A Reynolds-Averaged Navier-Stokes CFD code was used for the analysis using steady and unsteady simulations. The numerical investigation of the overall performance, efficiency and work-input characteristics of the fan were found to agree very well with the previously reported experimental results. The effect of casing treatment was investigated using two types of configurations, vaneless and vaned casing. The vaneless casing treatment produced a sizeable stall margin improvement with a measurable loss in both pressure rise and efficiency. The recess was fitted later with vanes and was shown to offer both a further stall margin improvement and an increase in the pressure rise coefficient without any significant drop in efficiency at design conditions. The effect of number of vanes inside the recess was also investigated by doubling and halving the number of vanes originally adopted. The predicted results highlighted the importance of the vane inside the casing. Unsteady simulations for the fan with solid and treated casing were carried out. The solid casing simulated for a single blade passage as well as for the entire fan containing all 27 blades highlighted the flow physics of the tip stall growth process, as a large amount of radial flow injected from the hub at the blade suction side near the trailing edge towards the outer casing and occupy this through a mechanism of radial low momentum flow transport. This transport process is the main contributor to the very large separation observed in the shroud region in addition to the locally induced separation due to high blade loading and tip clearance. Although the examination of the unsteady simulation of the recess treatment cavities does not offer an image of large scale unsteady activity at the flow condition investigated, this is on itself quite significant and enables the drawing of an important conclusion namely that large casing treatments rely primarily on a steady-state flow process. The corollary of this conclusion is of course that a steady-state simulation should then be sufficient to capture the essential features of the recess treatment.

La région d’étude est située à l’extrémité orientale du Zagros, à proximité du prisme d’accrétion du Makran, des Montagnes d’Oman et du golfe Persique. Ce système orogénique résulte de la collision en cours entre les plaques Arabe et Iran-Central. La caractéristique principale de la ceinture de plis du Zagros oriental (provinces du Fars et de Bandar Abbas) est l’existence d’un nombre important de diapirs de sel (sel d’Hormuz). La morphologie actuelle des diapirs de sel permet de proposer une typologie. Ainsi, nous proposons six différents types qui représentent aussi autant de stades d’évolution des structures au cours d’une histoire longue et complexe. Nous montrons que tous, ou presque tous, les diapirs étaient déjà actifs avant le plissement soit sous la forme de diapirs perçants, constituant des îles, soit sous la forme de dômes enfouis, actifs depuis le Paléozoïque Inférieur. Ces structures furent réactivés ultérieurement par des apports sédimentaires, des événements tectoniques (l’orogenèse du Zagros) et l’érosion de surface. Dans le détail, chaque diapir montre une évolution individuelle dépendant de sa position dans le système. Pendant l’orogenèse du Zagros, la formation d’Hormuz fut utilisée comme décollement basal séparant une couverture sédimentaire de 10 à 15 km d’épaisseur du socle Panafricain et de sédiments pré-Hormuz. Pendant l’orogenèse du Zagros (fin du Cénozoïque), des plis de décollement se développèrent sur un domaine qui était déjà ponctué par des diapirs de sel. Pour comprendre ce dispositif particulier, nous avons construit quatre coupes géologiques depuis le Golfe Persique, peu déformé, jusqu’aux zones internes du Zagros en utilisant de très nombreuses données de surface et de sub-surface. Le taux de raccourcissement de la partie plissée des coupes reste faible, moins de 10%. Les structures salifères pré-existantes influencent fortement tout à la fois la localisation et la direction des plis. C’est aussi ce que confirme des expériences analogiques originales
The studied area is located at the eastern tip of the Zagros system, close to the Makran accretionary prism Oman Mountains and Persian Gulf. This orogenic system results from the ongoing collision between the Arabian and Central-Iran plates. The main characteristic of the eastern Zagros fold thrust belt (Fars and Bandar-Abbas provinces) is the wide distribution of Hormuz salt diapirs. The present-day surface morphology of salt diapirs can be categorized into six types, which we suggest represent different stages in a long and complex history. We show that almost all the diapirs were already active prior to Zagros folding either as emergent diapirs forming islands or as buried domes initiated at as early as the Lower Paleozoic. They have been reactivated by subsequent sedimentary supply, tectonic events and surface erosion. In fact, each salt diapir shows individual evolution depending of their position in the system. During Zagros orogeny, the Hormuz salt layer acted as basal decollement level decoupling the basement (including pre-Hormuz sediments) from 10 to 15 km thick sedimentary cover. Salt cored detachment folds with variable trends developed during the Late Cenozoic in a domain, which was already punctuated by salt domes or diapirs. To understand such a particular layout, we constructed four geological cross-sections from the poorly deformed Persian Gulf to the inner part of Zagros Fold-Thrust Belt, using an important subsurface and surface data set. The Amount of shortening in the folded part of the sections remains low, less than 10%. Pre-existing salt structures (diapirs and dawn-building) strongly influenced both on the localization of folds and the direction of fold axes as also evidenced by original analogue experiments

In eastern Australia, the New England Fold Belt (NEFB) comprises an ancient convergent margin that was active from the Paleozoic until the late Mesozoic. Considerable effort has been expended in understanding the development of this margin over the past twenty years. However, proposed tectonic models for the orogen have either been too broad, ignoring contradictory local evidence, or too locally specific without paying attention to the 'big picture'. The research presented in this work addresses the issue of appropriate scale and depth of geological detail by studying the NEFB at the terrane-scale. Using one succession, the Silverwood Group of southeast Queensland, this work demonstrates that detailed sedimentological studies and basin analysis at the terrane-scale can help to refine hypotheses regarding the tectonic evolution of the NEFB. The Silverwood Group (Keinjan terrane), located approximately 140 km southwest of Brisbane, Australia, is a succession of arc-related basins that developed within an ancient intraoceanic island-arc during the mid-Cambrian to Late Devonian. From the base of the succession, the group consists of five formations totalling -9700 m. These include the Risdon Stud Formation (2500 m), Connolly Volcanics (2400 m), Bald Hill Formation (2450 m), Ormoral Volcanics (600 m) and the Bromley Hills Formation (1700 m). The Long Mountain Breccia Member (300m) is a separate unit which forms the lower part of the Bromley Hills Formation. The entire succession has been thrust west over the Late Devonian to Early Carboniferous Texas beds. Elsewhere, the Silverwood Group is unconformably overlain by and faulted against Early to Late Permian units including the Rokeby beds, Wallaby beds, Tunnel beds, Fitz Creek beds, Eight Mile Creek beds, Rhyolite Range beds and Condamine beds. Of these Permian units, all but the Condamine beds form part of the Wildash Succession. To the west, southwest and south, the Silverwood Group is intruded by the Late Triassic Herries and Stanthorpe Adamellites. All of these sequences and the two plutonic intrusives are unconformably overlain by the Jurassic sediments of the Marburg Sandstone. The Silverwood Group and Texas beds consist of various lithologies including grey, purple- grey, green and green-grey volcaniclastic conglomerates, sandstones, siltstones or mudstones, massive and laminated chert, polymict or monomict breccias, muddy breccias, muddy sandstones, and volcanic rocks. Volcanic rocks include various tholeiitic metabasites, dolerite, meta-andesites and infrequent metadacite. In the Silverwood Group, these volcanic rocks are often accompanied by mafic pyroclastic rocks (e.g. peperite and hyaloclastite). Facies analyses of these lithologies has led to the recognition of 19 deep-marine turbiditic and volcanic/volcaniclastic facies that were deposited by three main processes: i) gravity-flow processes (e.g. low- and high-density volcaniclastic turbidites and mass-flows), ii) chemical/biological processes (siliceous oozes- chert) and iii) direct initiation by volcanic processes (e.g. flows, hypabyssal intrusions and associated pyroclastic facies). For the Silverwood Group, the defined facies occur in distinct vertical associations that form recognisable 3rd and 4th-order architectural elements such as channel, levee, suprafan lobe, outer-fan, basin plain, mass transport complex, volcanic flows, syn-sedimentary sills and syn-sedimentary emergent cryptodomes. These architectural elements are represented in a series of deep-marine depositional environments including slope, shelf-edge failure, submarine-fan and subaqueous basaltic volcanoes. The Risdon Stud Formation and parts of the Connolly Volcanics were deposited along a 'normal' clastic or mud, mud/sand-rich and/or sand/mud-rich slope. Both upper and lower slope environments are represented and in both formations, the slope is speculated to have faced eastwards and prograded away from an active arc located west. Sediments from both successions accumulated at palaeodepths of 1200 to 2000 m. Although sediments from the upper part of the Bald Hill Formation were also deposited on a slope, these sequences have subsequently collapsed into the depocentre to form extensive slump deposits accompanied by olistoliths of older arc crust. The lower part of the Bald Hill Formation formed by similar processes, although the failure was far more extensive (>20 km along strike). This latter part of the formation is interpreted to be a major shelf-edge failure succession. Upper parts of the Bald Hill Formation also accumulated at palaeodepths of 1200 to 2000 m, but the deposition of these sediments occurred farthest from the shelf and at the greatest depth compared to the Risdon Stud Formation and Connolly Volcanics. Lower parts of the Bald Hill Formation were deposited at palaeodepths of approximately 1700 m. Subaqueous basaltic volcanoes are prominent in the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics. In the Bald Hill Formation, igneous rocks were emplaced into the shelf-edge failure succession as a series of syn-sedimentary sills and cryptodomes. These high-level hypabyssal rocks occasionally became emergent above the sediment-water interface, whereupon they were partially resedimented. In some parts of the Bald Hill Formation, the hypabyssal intrusions were blanketed by basin plain deposits that are contemporaneous with the slumps and olistoliths in the upper part of the formation. The intrusive rocks were emplaced at 1700 m palaeodepth. Unlike the Bald Hill Formation, the Ormoral Volcanics and lower parts of the Connolly Volcanics form thick accumulations of extrusive volcanic and pyroclastic rocks that built a significant volcanic pile. Volcanic and pyroclastic facies within these successions were deposited proximal to their source (0-10 km of vent). Extrusive rocks within the Ormoral Volcanics are thought to be derived from intrabasinal fissure-vents located at palaeodepths of 1700 to 3100 m. Igneous rocks from the Connolly Volcanics, Bald Hill Formation and Ormoral Volcanics have the petrological and geochemical characteristics of back-arc basin basalts (BAB) that were sourced from undepleted to slightly enriched Fertile MORB Mantle-wedge (FMM). The FMM material was variably enriched in trace elements by fluids derived from the subducting slab prior to emplacement of the igneous rocks. Immediately following emplacement, these rocks were hydrothermally metamorphosed under conditions of low-pressure and transitional low to high-temperature (200-300 °C). By contrast, igneous rocks within the Texas beds lack enrichment in subduction components and are characteristic of N-MORB. The Bromley Hills Formation is a sand-rich point-source submarine fan deposited at palaeodepths of 500 to 2000 m. The fan was initiated by a mass transport complex resulting from subaerial collapse of a basaltic-andesitic stratovolcano. The submarine fan is characterised by two repetitive stages of retrogressive sedimentation during which channel-levee elements (inner-fan channels) are overlain by suprafan lobe elements (mid-fan) and then by outer-fan deposits as sea-level rises within the depocentre. Both inner-fan channels and suprafan lobes show centralised stacking patterns with limited lateral migration that indicate the depocentre was laterally restricted during sedimentation (e.g. submarine ridges). The Bromley Hills Formation exhibits all the characteristics typical of an active margin fan that formed by a combination of tectonic stage initiation followed by eustatically controlled regressive deposition. Volcaniclastic sediments of the Silverwood Group range in composition from lithic to lithic- feldspathic wackes and arenites, although they are mainly lithic or feldspathic-lithic wackes and arenites. Many samples are tuffaceous (25-75% pyroclasts), particularly those from the Connolly Volcanics, Ormoral Volcanics and Bromley Hills Formation. Samples in the Bald Hills Formation and Texas beds can be classified as quartz-rich. The majority of the Silverwood Group was sourced from an undissected intraoceanic island-arc, although sediments within the Bald Hill Formation exhibit a provenance that is characteristic of uplift within the arc (recorded as a 'strike-slip continental arc' model). Epiclastic sediments from the Texas beds were sourced from a transitional to dissected continental arc. Formations of the Silverwood Group were mostly deposited in a series of intra-arc basins within an ancient intra-oceanic island arc, although the lowermost formation developed in a marginal basin (Risdon Stud Formation). All of the basins were located east of the active arc (behind the arc), keeping in mind the present location of the Group relative to the Texas-Coffs Harbour megafold. The entire succession formed during four-phases of arc-related basin development that coincide with major changes in the strain regime of the arc. From the base of the succession, these changes are: I) mid Cambrian to late Silurian marginal basin sedimentation- relative compression within the arc (Risdon Stud Formation), II) late Silurian to Early Devonian intra-arc rifting- relative extension within the arc (Connolly Volcanics), Ill) Early to early Middle Devonian basin collapse followed by intra-arc rifting- relative extension to compression (Bald Hill Formation and Ormoral Volcanics) and IV) early Middle to Late Devonian intra-arc submarine fan sedimentation- relative compression (Bromley Hills Formation). Comparing the Silverwood Group against equivalent terranes of Cambrian to Devonian age within the New England Fold Belt (NEFB) suggests that the Gamilaroi terrane, Calliope Volcanic Assemblage, Willowie Creek beds and Silverwood Group all formed as one intraoceanic island-arc during the Early to Late Devonian. Prior to this, significant differences in the sedimentological evolution of these terranes suggests that they occupied different positions relative to each other within the one arc. It is proposed that the NEFB formed as a result of dual west-directed subduction zones during the Cambrian to Middle Devonian period. During this time, a single intraoceanic island-arc located seaward of the Australian craton developed above a west-directed subduction zone. This arc was separated from the craton by a marginal sea. A second west-directed subduction zone was located beneath a continental arc developed on the Australian craton. Cambrian to Early Devonian terranes within and along the Peel Fault are proposed to form a part of the ancient subduction zone present beneath the intraoceanic island-arc (Weraerai and Djungati terranes). Collision of the intraoceanic island-arc occurred during the Late Devonian, at which point west-directed subduction occurred beneath the Australian craton and the accreted intraoceanic island-arc. Following collision, a new continental volcanic arc was established that was active during the Late Devonian to Early Carboniferous.

Grâce aux données de forages ODP du Leg 155, corrélées aux coupes sismiques haute résolution de la campagne Lobestory d’Ifremer, l’éventail géant de l’Amazone est devenu une zone privilégiée pour étudier l’évolution des systémes chenaux-levées et le processus d’avulsion qui régit l’architecture des systémes turbiditiques. Les travaux antérieurs avaient montré que le processus d’avulsion est un des processus fondamentaux de la construction des édifices turbiditiques. Il aboutit au changement brutal du cours d’un chenal et à son abandon en aval du point d’avulsion. Ce processus et les phénoménes qui en découlent (courants non-confinés, rupture de profil d’équilibre du chenal, etc. ) sont à l’origine d’une distribution sédimentaire particulière, avec des dépôts grossiers (HARPs) en semelle des chenaux. Dans le travail présenté, les paquets de réflecteurs de fortes amplitudes (HARPs) situés à la base de ces systèmes fortement aggradant, ont pu étre caractérisés en sismique comme la superposition de 4 corps sismiques élémentaires correspondant à des processus de mise en place distincts. Ils peuvent étre décrits comme une amalgamation de petites unités sableuses, chenalisées ou non, mises en place pa une succession de courants de turbiditié très sableux et de haute densité. L’étude sismique et bathymétrique de corps particuliers repérés dans l’éventail du Zaïre a permis de compléter notre connaissance des premiers (effondrement de la levée) et derniers stades (abandon du chenal père et début d’aggradation du chenal fils aprés dépôts des HARPs). Ces résultats ont permis de préciser les modèles d’avulsion proposés jusqu’ici
Our study focuses on the avulsion process, the key process for the depocenter migration of stacked channel-levee systems in the deepsea. To present, the avulsïon process has been explained as the abandonment of a channel (parent channel) and the birth of a new one (new channel). A true indice of avulsion has been given by the detection of the HARPs, a seismic term known since the 80s for highamplitude reflection packets at the base of new channel-levee systems. The HARPs are suggested, in analogy to the studies from ODP Leg 155 of the Amazon Fan, to be sandy deposits in lows adjacent to breached parent channels. Our present work, by re-visiting the Amazon Fan with multichannel high-resolution seismic data, highlights the great complexity of the HARPs architecture and their lithological heterogeneity. The study of some specific zones within the Zaïre Fan allowed revealing both the earliest stages of an avulsion process related to levee breaches and first splays linked to unconfined flows on the levee, and the latest stage of this process, with the first levee deposition and evolution following the HARPs deposition. These results provide new insights for the understanding of the processes involved during an avulsion event (levee breach, HARPs accumulation, levee aggradation). By describing the inter-relationship of the different architectural sub-bodies of the HARPs and giving details on both the earliest and latest stages of the avulsion, our results also provide clues to refine the previous conceptual models and reach a higher resolution knowledge of this process

In the past couple of decades, the discovery that iron is a limiting nutrient in large regions of the ocean has spurred much research into characterizing the biogeochemical controls on iron cycling. While Fe(II) is soluble at circumneutral pH, it readily oxidizes to Fe(III) in the presence of oxygen. Fe(III) is highly insoluble at circumneutral pH, presenting organisms with a bioavailability paradox stemming from the physiological challenge of using a solid phase mineral for assimilatory or dissimilatory purposes. Interestingly, dissolved organic-Fe(III) complexes can be stable in seawater in the presence of oxygen, and an active flux of these complexes has recently been measured in estuarine sediments. Their sources and biogeochemical role, however, remain poorly understood. In this work, a suite of field and laboratory techniques were developed to quantify diagenetic processes involved in the remineralization of carbon in marine sediments in situ, investigate the role of these organic-Fe(III) complexes in sediment biogeochemistry, and characterize the composition of the ligands possibly involved in the solubilization of Fe(III) in marine sediments. The first-of-its-kind in situ electrochemical analyzer and HPLC was used to better constrain diagenetic processes that may lead to the formation of dissolved organic-Fe(III) complexes in the Altamaha estuary and Carolina slope. An intensive study of the Satilla River estuary reveals that dissimilatory iron-reduction contributes to the formation of sedimentary organic-Fe(III) complexes, which are demonstrated to serve as an electron acceptor in subsequent incubations with a model iron-reducing microorganism. Similar observations in deep-sea slope and abyssal plain sediments fed by the Mississippi and Congo Rivers suggest that dissimilatory iron reduction may represent an important component of carbon remineralization in river-dominated ocean margin sediments that may be currently underestimated globally. To confirm that these organic-Fe(III) complexes are produced during microbial iron reduction, novel separation schemes were developed to extract and identify Fe(III)-binding ligands from sediment pore waters. Preliminary results reveal the presence of a few select low-molecular weight compounds in all pore waters extracted, suggesting they might be endogenous ligands secreted by iron-reducing bacteria to non-reductively dissolve Fe(III) minerals prior to reduction.

This thesis explores women’s writing and its place in the formation of female film culture in the British silent cinema era. The project focuses upon women’s literary engagement with silent cinema as generative of a female film culture, looking at materials such as fan letters, fan magazines, popular novels, short story papers, novelizations, critical journals and newspaper criticism. Exploring this diverse range of women’s cinema writing, the thesis seeks to make an original contribution to feminist film historiography. Focusing upon the mediations between different kinds of women’s cinema writing, the thesis poses key questions about how the feminist film historian weights original sources in the reclamation of silent female film culture, relative to the varying degrees of cultural authority with which different women commentated upon, reflected upon, and creatively responded to film culture. The thesis moves away from conceptualization of cinema audiences and reception practices based upon textual readings. Instead, the thesis focuses upon evidence of women’s original accounts of their cinemagoing practices (fan letters) and their critical (newspaper and journal criticism) and creative (fiction writers) responses to cinema’s place in women’s everyday lives. Balancing original archival research with multiple overarching methodological frameworks—drawing upon fan theory, feminist reception theory, audience studies, social history and cultural studies—the thesis is attentive to the diversity of women’s experiences of cinema culture, and the literary conduits through which they channeled these experiences. Shifting the recent focus in feminist silent film historiography away from the reclamation of lost filmmaking female pioneers and towards lost female audiences, the thesis thus constructs a nationally specific account of British women’s silent era cinema culture.

L’objectif de cette étude est de reconstruire le régime de l’érosion des chaînes himalayennes, et de relier ces paramètres aux variations climatiques globales et à l’intensité de la mousson. Dans ce travail, Les sédiments de 3 carottes prélevées dans la baie du Bengale pendant la mission MONOPOL ont fait l’objet d’analyses minéralogiques (XRD et granulométrie) et géochimiques (majeurs, traces, la composition isotopique du Nd et du Sr). La mise en âge des carottes, est basée sur les enregistrements de δ¹⁸O de foraminifères planctoniques (G. ruber), et des datations au ¹⁴C (AMS). Ces 3 enregistrements sédimentaires couvrent les derniers 180 ka. L'approche multi-traceur menée sur ces carottes, nous donne des informations essentielles sur les sources, afin de reconstruire les changements au cours du temps des sédiments transportés vers la partie proximale du cône sous-marin du Bengale, et de mieux comprendre ses liens potentiels avec les changements climatiques (mousson indienne et/ou des changements au niveau de la mer). Les résultats de cette étude, donnent également des clefs sur les processus d'altération chimique et de la dynamique du transport des sédiments au cours du temps. En outre, une étude à haute résolution, sur un site localisé sur la levée du chenal actif du cône sous-marin fournit des informations sur les changements dans le degré d'altération et la dynamique de transport des sédiments du système himalayen au cours de l'Holocène. Ainsi, il est possible de quantifier l'impact de la mousson d’été sur la sédimentation au niveau de la levée durant cette période climatique. Les résultats de cette étude ont été utilisés pour estimer les changements dans les sources sédimentaires (plaine Indo-Gangétique vs haute-chaine) et retracer l'altération chimique du matériel détritique au sein du bassin versant du système fluviatile du Ganges-Brahmapoutre
The aim of this study is to reconstruct the erosional history of the Himalayan ranges, in order to connect these parameters to global climatic events and variations in the intensity of the monsoon. In this work, sediments from 3 marine cores collected in the Bay of Bengal, during the MONOPOL cruise were analyzed using mineralogical (XRD and grain-size) and geochemical (major, trace, Nd and Sr isotopic composition) methods. Chronological framework of studied cores were based on δ¹⁸O from planktonic foraminifera (G. ruber), and ¹⁴C ages dating (AMS). These cores cover the last 180 kyr. The multi-proxy approach conducted on these cores, gives us critical information about the source, to reconstruct the temporal variability of sediment export to the proximal northeastern Bengal Fan and its potential links to climatic changes (Indian monsoon and/or sea-level changes). Results also give insights on the chemical weathering processes and the dynamic of transport of the sediments through time as well. Moreover, a high-resolution study, on a site located on the active middle fan channel levee of the fan provides information on changes in the weathering pattern and the dynamic of transport of sediments from the Himalayan system during the Holocene. Thus, it is possible to quantify the impact effect of summer monsoon rainfall during that time interval. These results have been used to assess changes in the sedimentary sources (Indo-Gangetic plain vs highlands) and document the chemical weathering states of the detrital material within the Ganges-Brahmaputra river basin catchment

La restitution de la géometrie originelle des corps sédimentaires (cartographie, décompaction), l'étude du fonctionnement des morphologies et l'approche des paléoprofondeurs (microfaune), jointes à l'analyse séquentielle rythmée par la tectonique synsédimenatire, illustrent la dynamique du bassin subalpin au long de l'apto-cenomanien. L'Apto-Cénomanien des chaînes subalpines méridionales a fourni le support d'un travail méthodologique orienté vers la restitution à toutes les échelles et dans leur configuration originelle (décompaction) de la géométrie des corps sédimentaires dans leur contexte dynamique. La série étudiée correspond, à la partie inférieure du dernier grand rythme mésozoïque conduisant à la fermeture du bassin subalpin. Limitée à la base et au sommet par deux discontinuités majeures, elle s'organise en dix-neuf séquences, regroupées en deux mégaséquences de même polarité (marne -> marno-calcaire): Aptien (1); Albo-Cénomanien (II). Ce découpage séquentiel forme la trame de cette étude tant pour les problèmes biostratigraphiques que paléogéographiques; il a naturellement conduit à s'interroger sur la signification des séquences sédimentaires.

This thesis examines the sedimentological processes, internal architecture and depositional evolution of the deep marine Tithonian succession of the Angel Formation located within the Dampier Sub-basin on the North West Shelf of Australia. It is a mature basin containing 149 hydrocarbon fields with combined reserves of 34tcf of gas, 1037mmbbls of condensate and 633mmbbls of oil within fluvio-deltaic and deep marine reservoirs. The rationale of this research is to improve current understanding of the highly prosperous deep marine reservoirs whose architecture is primarily of sub-seismic resolution. It was accomplished using lithofacies classifications and the establishment of an architectural scheme comprising seven orders in combination with wireline, biostratigraphic and seismic reflection data and applicable analogues. Eleven cores totalling 547 metres were analysed to identify sedimentological processes responsible for the deposition of the Angel Formation and to develop lithofacies schemes. The depositional lithofacies scheme contains six types formed through the deposition of quasi-steady high density turbidity flows and debrites. The lithofacies scheme for deformed sediments contains five types generated by post-depositional sediment movement, including soft sediment slumping and subsurface remobilization. These core-scale lithofacies represent first and second order architectural elements. Third order architectural elements are represented by seven lithofacies associations. They are grouped into two categories dependent on their association with channelisation. Channelised lithofacies associations include crevasse splays, channel axis units, channel margin units, and channel abandonment units. Unchannelised lithofacies associations include proximal sand-dominated frontal splays, distal silt-dominated frontal splays and splay abandonment units. Third order lithofacies associations are grouped into fourth and fifth order architectural elements that represent the development of composite channel-splay or sheet complexes. A fourth order architectural element is represented by a single storey migrational channel feature. Five differing fifth order architectural elements are separated into two complexes dependent on their degree of internal channelisation. A composite channel-splay complex comprises stacked fourth order channel forms that develop through multiple episodes of infilling and reincision. They are overlain by retrogradational splay or lateral channel margin deposits dependant on their place within a sixth order setting. A composite sheet complex comprises solely of stacked progradational and retrogradational splays. Sixth order architectural elements group multiple fifth order complexes amalgamated through autocyclic processes into allocyclic successions bound by sequence boundaries and maximum flood events. Sixth order progradational models are related to early and late lowstand time. Stacked fifth order architectures deposited during sixth order progradational cycles display high net to gross sandstones, low channel sinuousity and increased amalgamation of channel forms. Sixth order aggradational and retrogradational models are related to transgressive periods. Stacked fifth order architectures deposited within these systems become increasingly clay-rich, are more sinuous, have more avulsive events as channels aggrade above the equilibrium profile, and become less amalgamated as fourth order channel forms decrease in size and become interbedded with sheet complexes. Sixth order architecture and seventh order fan evolution is examined using a combination of fifth order stacked architectures, wireline and seismic data. The Parker Terrace, which contains the Mutineer, Lambert, Egret and Montague fields, contains a seventh order system that comprises curved, coalescing fan systems up to 15 kilometres long separated by up to six lowstand events. The central Dampier Sub-basin, which contains the Angel, Cossack and Wanaea fields, contains a seventh order fan system up to 50 kilometres long also separated by up to six lowstand events. This regional architectural analysis demonstrates that the majority of sediment in the Dampier Sub-basin during Tithonian time was deposited along the basin’s central axis. Additional sediment was sourced from the Rankin Trend in the west to form small fan systems along the Parker Terrace. Non-depositional processes play a critical role in the lateral distribution and post-depositional subsurface profile of architectural elements. Active tectonism may have influenced lithofacies distribution and the location of feeder complexes in the Angel, Egret and Montague fields. Subsurface remobilisation of sandstones led to the formation of clastic injectites in fields along the Parker Terrace and sub-vertical polygonal fault injectites in fields within the central basin axis. These features can influence the lateral and vertical connectivity of depositionally independent reservoir intervals. The high resolution sub-seismic scaled architectural system can be applied in combination with seismic interpretation to help constrain the exploratory risk of stratigraphic plays. Furthermore, it can assist future development programs of discovered hydrocarbon accumulations by enhancing knowledge of lateral architectural variability away from the borehole.
Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2011

碩士
國立彰化師範大學
地理學系
104
The study investigated the effects of the application of Marine Education in the subject of Geography in junior high school. Both the local features and the concepts from the indexes of Marine Education were integrated in the project. A total 224 participants from Fang Yuan Junior High School took a part in this project, which included the presentation of the concepts, beach cleanups, field works, pretests, and post-tests. The understandings of Marine Education before and after the project were compared. The study also explored the main factors of successful class of Marine Education integration in Geography, providing an example for further studies for the junior high school with similar location. In this experimental design, the participants are divided into the experimental group and the control group. The experimental group further joined the field works, but the control group did not. The research findings were as follows. First, the differences before and after the project were statistically significant, especially in the experiment group. Second, most of the participants performed better on the two topics: marine culture and marine environment; however, on the topic of marine society, it was relatively difficult for the participants. Last, the main factors that influenced the participants' learning effect were: grades, residences, or the experiences of taking a boat and fishing.

The well-known clinoformal geometry of a basin-fill, with an alluvial to shelf segment, deep-water slope segment, and a basin floor segment, arises from the development of a wedge-shaped body of sediment at the basin-margin that has been termed a basin-margin wedge or a shelf-slope sedimentary prism. The basin-margin wedge characteristically has atopset-foreset clinoformal geometry, with its topset dominated by alluvial, coastal and shelfal processes, while its foreset is dominated by turbidite sedimentation. Tectonic configuration of the basin, sediment supply, and relative sea level variation are some of the major factors that control the development and growth of the basin-margin wedge. This dissertation documents two distinct stages of development of the basin-margin wedge at an Eocene active margin, and relates the observed variability in the nature of the shelf-margin, deep-water slope, and basin-floor deposits with these stages. The Tyee Basin in western Oregon was a forearc basin that was filled during late early Eocene and Middle Eocene under greenhouse climatic condition. The sedimentary succession of the Tyee Basin include continental, shallow-marine and deep-water sandstones that are well exposed in Coast Range area of Oregon. The variability observed within the thick and laterally extensive turbidite sandstones of the Tyee Basin led to contrasting depositional models for the Tyee basin in the past. Notably, the submarine ramp model, which provides an alternative model for deepwater coarse clastic deposition, was proposed based on the sedimentary succession of the Tyee Basin. Reconstruction of the clinoformal geometry of the Tyee Basin succession from detailed field data (more than 1000 outcrop locations) and subsurface data reveals two distinct stages of development of this active basin-margin. Each stage has a distinct style of clinoform development and a distinct character of associated sandy deepwater deposits. At the initial stage the basin-margin clinoforms appear to be small (< 250m clinoform height) and strongly progradational, with clinoform topset dominated by the feeder fluvial deposits. At this stage, sandy unconfined (not channelized) turbidite deposits accumulated on the Tyee deepwater slope and extended to the Tyee basin-floor. Large scale sediment conduits on the deepwater slope, in the form of slope channels or canyons, are notably absent in this stage. The second stage is characterized by larger clinoform height (> 500m), higher degree of topset aggradation with repeated fluvio-deltaic cycles on the shelf, and spectacular, sand-rich, well-organized turbidite channels and canyons on the slope. The slope channels active at this stage supplied coarse sediments to the basin-floor to form unusually thick basin-floor fans. The first infill stage represents the embryonic development of a basin-margin wedge on the Tyee continental margin, and could have some similarity with the previously mentioned submarine ramp model. But this was followed by a much longer period of basin-filling when repeated fluvial and shallow-marine cycles formed on the shelf and well-organized turbidite channels were active on the slope supplying sands to the Tyee Basin floor fans. It was concluded that the two stages of development of the basin-margin wedge in the Tyee Basin is controlled largely by the configuration of the basin, that is a result of the prominent topographic/bathymetric features in oceanic basement underlying the sedimentary succession of the Tyee Basin. Tectonically active hinterland and greenhouse climate may have contributed to a relatively high sediment supply to the basin. The relatively small-amplitude sea level variations expected under greenhouse climatic condition of the Early to Middle Eocene are likely to have relatively minor effect on the architecture of the basin-fill. The present work on Tyee Basin builds on earlier research on this basin, but now establishes a ground trothed clinoformal growth model, revises the existing interpretation of sediment transport direction during a major part of the basin-filling history, and demonstrates a two-stage evolution of margin accretion. The observations from the active Tyee Basin was compared and contrasted with a latest Pleistocene sediment wedge on the New Jersey outer shelf. This sediment wedge, developed under icehouse climatic condition, and on a passive margin, was studied using high resolution seismic data (CHIRP). In contrast to the sedimentary succession of the Tyee Basin, the depositional architecture of the sediment wedge on outer New Jersey shelf, which was interpreted as a set of falling stage deltaic clinothems, appears to be strongly controlled by eustatic sea level variation of latest Pleistocene.
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