O objetivo do presente trabalho consiste no estudo das características dos sedimentos de superfície de fundo da Baía da Ilha Grande, estado do Rio de Janeiro, e sua correlação com os processos hidrodinâmicos atuais,bem como com a evolução sedimentar do litoral paulista e sul-fluminense a partir do máximo regressivo do Pleistoceno Superior. A baía da Ilha Grande consiste num corpo de água definido pela presença da Ilha Grande. Pode ser dividida em três unidades fisiográficas distintas, a saber: Porção Oeste, Porção Leste e Canal Central. Para o presente estudo, foi coletado um total de 153 amostras de superfície de fundo e realizado um conjunto de análises sedimentológicas constituído por: análise granulométrica, análise morfométrica e de textura superficial, análise de conteúdo em carbonato biodetrítico, analise de conteúdo em matéria orgânica, análise dos constituintes na fração grosseira e analise de assembléias de minerais pesados. Os estudos realizados permitiram identificar quatro fácies sedimentares distintas, caracterizadas como: sedimentos relíquias da Porção Leste, sedimentos atuais do Canal Central e das áreas abrigadas, sedimentos transgressivos da Porção Oeste e sedimentos mistos resultantes da mistura de termos das fácies anteriores.Finalmente, é feita uma proposta de evolução sedimentar da área a partir do máximo regressivo de 18.000 anos A.P. estabelecidas considerações sobre a dinâmica de fundo da baía. / The objective of the present work is to study the characteristics of the surface bottom sediments of Ilha Grande Bay, Rio de Janeiro state, and their correlation with the modern hydrodynamic processes, as well as with the sedimentary evolution of the southeastern brazilian coastal region, since the maximum regression of the Upper Pleistocene. Ilha Grande Bay consista a water body defined by the presence of Ilha Grande island. It can be divided into three distinct fisiographic units: the Western Portion, the Eastern Portion, and the Central Channel. In this work, a total of 153 surface bottom samples were collected, and the sediments were anal zed for: grain size, morphometry and surface texture, carbonate content, organic matter content, coarse fraction constituents, and heavy mineral assemblages. The studies allowed to identify four distinct sedimentary facies, characterized as: relict sediments of the Eastern Portion, modern sediments of the Central Channel and the confined areas, transgressive sediments of the Western Portion, and mixed sediments, resulting from the mixture of the previous facles. Finally, we propose amodel for the sedimentary evolution of the area since the maximum regressive of 18,000 years B.P. and considerate on the bottom dynamic of the bay.

The Arcadia Formation is a mixed carbonate-siliciclastic rock unit that existed as a shallow carbonate ramp to platform environment during the Late Oligocene to Early Miocene Epoch. It can be divided into two distinct, informal sections based on lithological properties: the upper Arcadia Formation and lower Arcadia Formation. The sections are part of a major, third-order sequence that can be further divided into four higher-frequency, lower magnitude sequences: ARS1, ARS2, ARS3, and ARS4. The sequence boundary separating ARS2 and ARS3 represents a drastic change in the depositional regime from a high-energy, inner ramp/platform to a lower-energy, deep outer ramp environment. ARS3 represents the period of maximum flooding and constitutes a major portion of the regressive system tract (RST) of the third order depositional sequence. In certain sections, the Arcadia Formation is heavily bioturbated including ichnotaxa from the glossifungites, cruziana, and scolithos inchofacies. Thalassinoides sp. burrows of the glossifungites ichnofacies were found to be commonly associated with firmground substrates and breaks in sedimentation. The lithofacies associations were grouped into paleodepositional environments that ranged from restricted marine to deep outer ramp with lithology ranging from grainstone to wackestone to mudstone with variable amounts of siliciclastic and phosphatic constituents. Each sequence boundary extends regionally south from Broward County to southern Miami-Dade County utilizing gamma-ray geophysical signatures unique to each sequence. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

A análise batimétrica e sísmica de alta resolução realizadas na Plataforma Continental Externa e Talude ao largo da Ilha de São Sebastião permitiu elaborar um modelo morfológico e sedimentar para região. A Plataforma Continental Externa apresenta uma morfologia extremamente irregular, com presenças de montiformas, escarpas e depressões erosivas. Estas feições e os seus sedimentos superficiais são de origem carbonáticas. Na região da quebra da Plataforma e Talude superior ocorre um intenso processo erosivo, causada pela ação da Corrente do Brasil ao longo do tempo, formando canais e escarpas na região. Ao longo do Talude observam-se inúmeras feições que estão distribuídas por faixas de profundidade. Nos setores mais rasos observam-se há presença de ondas de sedimento e pockmarks ativos e inativos. Abaixo dos 1000 metros as feições predominantes são os canais e depósitos contorníticos, como o Canal de Santos, que possui expressão regional, localizado paralelamente ao talude. Esses depósitos e canais contorníticos são formados e retrabalhados pela incidência das Correntes de Contorno Intermediária (CCI) e da Corrente Contorno Profunda, que sofreram variações ao longo do tempo. / The analysis of high-resolution bathymetric and seismic data from the Outer Continental Shelf and Slope in front of São Sebastião\'s Island allowed us to elaborate a morphological and sedimentary model for the region. The Outer Continental Shelf has an extremely irregular morphology, with the presence of montiforms, scarp and erosive depressions. These features and surface sediments are carbonate. In the shelf break and upper slope occurs an intense erosion, caused by the action of the Brazil Current through time, forming channels and scarps in the area. It was observed that the features over the slope are distributed by depth ranges. In shallower sectors was found active and inactive feature such as sediment waves and pockmarks. Below 1000 meters the predominant features are channels and contourite deposits such as Santos\'s Channel, which has a regional expression and is located parallel to the slope. The formation and rework of these features occurs by the incidence of intermediate boundary current (IBC) and deep boundary current (DBC) and their variation through time.

A análise batimétrica e sísmica de alta resolução realizadas na Plataforma Continental Externa e Talude ao largo da Ilha de São Sebastião permitiu elaborar um modelo morfológico e sedimentar para região. A Plataforma Continental Externa apresenta uma morfologia extremamente irregular, com presenças de montiformas, escarpas e depressões erosivas. Estas feições e os seus sedimentos superficiais são de origem carbonáticas. Na região da quebra da Plataforma e Talude superior ocorre um intenso processo erosivo, causada pela ação da Corrente do Brasil ao longo do tempo, formando canais e escarpas na região. Ao longo do Talude observam-se inúmeras feições que estão distribuídas por faixas de profundidade. Nos setores mais rasos observam-se há presença de ondas de sedimento e pockmarks ativos e inativos. Abaixo dos 1000 metros as feições predominantes são os canais e depósitos contorníticos, como o Canal de Santos, que possui expressão regional, localizado paralelamente ao talude. Esses depósitos e canais contorníticos são formados e retrabalhados pela incidência das Correntes de Contorno Intermediária (CCI) e da Corrente Contorno Profunda, que sofreram variações ao longo do tempo. / The analysis of high-resolution bathymetric and seismic data from the Outer Continental Shelf and Slope in front of São Sebastião\'s Island allowed us to elaborate a morphological and sedimentary model for the region. The Outer Continental Shelf has an extremely irregular morphology, with the presence of montiforms, scarp and erosive depressions. These features and surface sediments are carbonate. In the shelf break and upper slope occurs an intense erosion, caused by the action of the Brazil Current through time, forming channels and scarps in the area. It was observed that the features over the slope are distributed by depth ranges. In shallower sectors was found active and inactive feature such as sediment waves and pockmarks. Below 1000 meters the predominant features are channels and contourite deposits such as Santos\'s Channel, which has a regional expression and is located parallel to the slope. The formation and rework of these features occurs by the incidence of intermediate boundary current (IBC) and deep boundary current (DBC) and their variation through time.

O objetivo do presente trabalho consiste no estudo das características dos sedimentos de superfície de fundo da Baía da Ilha Grande, estado do Rio de Janeiro, e sua correlação com os processos hidrodinâmicos atuais,bem como com a evolução sedimentar do litoral paulista e sul-fluminense a partir do máximo regressivo do Pleistoceno Superior. A baía da Ilha Grande consiste num corpo de água definido pela presença da Ilha Grande. Pode ser dividida em três unidades fisiográficas distintas, a saber: Porção Oeste, Porção Leste e Canal Central. Para o presente estudo, foi coletado um total de 153 amostras de superfície de fundo e realizado um conjunto de análises sedimentológicas constituído por: análise granulométrica, análise morfométrica e de textura superficial, análise de conteúdo em carbonato biodetrítico, analise de conteúdo em matéria orgânica, análise dos constituintes na fração grosseira e analise de assembléias de minerais pesados. Os estudos realizados permitiram identificar quatro fácies sedimentares distintas, caracterizadas como: sedimentos relíquias da Porção Leste, sedimentos atuais do Canal Central e das áreas abrigadas, sedimentos transgressivos da Porção Oeste e sedimentos mistos resultantes da mistura de termos das fácies anteriores.Finalmente, é feita uma proposta de evolução sedimentar da área a partir do máximo regressivo de 18.000 anos A.P. estabelecidas considerações sobre a dinâmica de fundo da baía. / The objective of the present work is to study the characteristics of the surface bottom sediments of Ilha Grande Bay, Rio de Janeiro state, and their correlation with the modern hydrodynamic processes, as well as with the sedimentary evolution of the southeastern brazilian coastal region, since the maximum regression of the Upper Pleistocene. Ilha Grande Bay consista a water body defined by the presence of Ilha Grande island. It can be divided into three distinct fisiographic units: the Western Portion, the Eastern Portion, and the Central Channel. In this work, a total of 153 surface bottom samples were collected, and the sediments were anal zed for: grain size, morphometry and surface texture, carbonate content, organic matter content, coarse fraction constituents, and heavy mineral assemblages. The studies allowed to identify four distinct sedimentary facies, characterized as: relict sediments of the Eastern Portion, modern sediments of the Central Channel and the confined areas, transgressive sediments of the Western Portion, and mixed sediments, resulting from the mixture of the previous facles. Finally, we propose amodel for the sedimentary evolution of the area since the maximum regressive of 18,000 years B.P. and considerate on the bottom dynamic of the bay.

Despite mounting demand for a more sustainable worldwide water supply system, available reservoir capacity is relentlessly diminishing due to sedimentation. This fact, coupled with a decrease in the rate of dam construction, indicate an impending water supply dilemma. In the future, dams should be designed following a life cycle management approach rather than the typical short-sighted design life technique.Neither sustainable reservoir lifespans nor intergenerational equity is achieved through conventional cost-benefit analyses (CBA), which render all benefits and costs projected to occur more than several decades into a project as negligible. Consequently, future expenditures, including dam decommissioning or retrofitting with sediment management facilities, are regarded as non-factors in an analysis. CBAs have also historically failed to account for the impacts of sedimentation on infrastructure and the environment over time.Alternatives to the traditional application of the CBA do exist, however. These include dam owners establishing retirement funds or insurance policies, beneficiaries paying for rehabilitation or maintenance, and economists incorporating infrastructure damages and potentially declining discount rates into their analyses.To analyze the disadvantages of not managing sediment, a case study of costs caused from sedimentation impacts at Gavins Point Dam was performed. Impacts from sedimentation at Gavins Point Dam include, among many others, upstream municipal flooding and downstream bank stabilization and sandbar construction. The financial analysis considered the time value of money and showed that the value of expenditures to resolve sedimentation impacts is equivalent to 70% of the original construction cost. Including the costs of additional impacts would amplify this result. Design and operations decisions at Gavins Point Dam could have been drastically different, leading to a more sustainable project, if these expenditures from sedimentation impacts had been included in the initial economic analyses.It is recommended that multidisciplinary discussions occur at multiagency levels to consider changes to traditional CBAs for long-term water supply projects. These discussions should investigate the creation of funding to address sediment management at existing dams. The frequency of bathymetric surveys should also be increased, which would lead to a better understanding of the condition of our infrastructure. By pursuing these recommendations and integrating the aforementioned alternatives to the CBA, economic studies for reservoirs will be more accurate, reservoir lifespans will be more sustainable, profits will be extended indefinitely, and the economic burdens passed to future generations will be lessened.

The study area is located in central Columbia County and encompasses approximately 373 square kilometers. The purpose of the study was to map lithofacies to a scale of 1:31250, study the petrography of the lithofacies, determine the stratigraphy, and develop a model for environment of deposition of the Scappoose Formation.

Over a span of six days from November 2-7, 2006 approximately 43 cm of precipitation fell over the Hood River Basin in Oregon. A lahar was initiated on the Eliot Branch of the Middle Fork Hood River by two or more landslides that occurred on the lateral moraines of the Eliot Glacier on the early part of November 7th, 2006. The Eliot Branch lahar was embedded within the larger regional flood that was occurring in the Hood River Basin and traveled a total of 48 km from the initiation points on the north flank of Mount Hood to the Hood Rivers confluence with the Columbia River. The initiating landslides abruptly transformed into a debris flow upon mixing with flood waters of the Eliot Branch. The debris flow traveled a distance of ~28 km at which point it was transformed first to a hyperconcentrated flow and then to water flow via selective deposition of coarse sediment and progressive dilution by channel flow waters from the East and West Fork Hood Rivers. The transformation from debris flow to hyperconcentrated streamflow was recorded by a thickening wedge of hyperconcentrated streamflow sediments found above and below progressively fining debris flow sediments over a reach of 22 km. Finally, the hyperconcentrated-flow phase of the lahar transformed to water flow and then traveled an additional 20 km to the Hood River delta. Upon reaching the apex of the Hood River delta, depositing sediments led to an expansion of the delta. Debris-flow sediments were predominantly gravel (36.0-69.7% by wt.) with sand (22.1-55.9% by wt.) and fines (4.7-7.8% by wt.). Hyperconcentrated flow deposits contained a larger sand fraction of (66.8-99.2% by wt.) with few gravel clasts (0-26.0% by wt.) and fines (0-8.8% by wt.). Water flow deposits averaged 90.5% (wt.) sand with 6.0% (wt.) gravel and 3.0% (wt.) fines. Sorting was a key factor in flow identification and showed progressive improvement downstream from the initiation point. Sorting values for the flow types are as follows: debris flow deposits ranged from 3.3Φ (very poorly sorted) to 1.8Φ (poorly sorted), hyperconcentrated flow deposits ranged from 2.4Φ (very poorly sorted) to 0.8Φ (moderately sorted), and water flood deposits ranged between 1.4Φ (poorly sorted) to 0.6Φ (moderately sorted).

Climate variability has had a dramatic impact on eastern Grand Canyon tributaries over the past -100 ky. This is readily observed in the Lava Chuar and Comanche catchments, which host well preserved colluvial remnants and river terraces that resulted from several climate-induced cycles of aggradation and incision. This study investigates these climate responses using surveying, sedimentology, and luminescence geochronology methods to investigate the mechanisms and timing of their deposition. The survey data demonstrate that the concavity of terrace treads is lower than modern drainages. The sedimentology suggests the prevalence of stream-flow reworking of debris flow deposits and portrays an expected down-stream fining of deposits. Results of geochronology indicate that Lava Chuar Creek aggraded from -100-90 ka (S4), 61-55 ka (S3o), 50-35 ka (S3y), and 14-7 ka (S2). Comanche Creek similarly aggraded twice during the time period from 77-35 ka (S3) and also from 26-22 ka (S2). The response of eastern Grand Canyon tributaries to glacial-interglacial climate cycling appears to be more complicated than formerly thought. Previous conceptual models assumed that stream aggradation in arid settings occurred as a response to one specific set of climatic and biologic conditions, but new field data and luminescence dates on terrace materials reveal that there are at least two sets of conditions that were conducive to aggradation along local streams. First, streams aggraded during cooler, wetter climates, which is inferred to be due to increased sediment supply (e.g. S4 and S3y in Lava Chuar). With the transition to warmer interglacial climates came higher intensity storms and decreased vegetation density in catchments, based on previous paleoclimate studies. These conditions caused remobilization and redeposition of older sediment and resulted in a second set of stream aggradation phases (e.g. S3o and S2 in Lava Chuar). Meanwhile, the Colorado River aggraded only once per climate cycle during glacial advances and subsequent climate transitions. Thus, tributaries have responded more frequently and more sensitively to changing local conditions compared to the relatively insensitive Colorado River. This is supported by tighter correlation of tributary records to trends in regional paleoclimate records than to global ice records.

Abstract not available