Dissertations / Theses: 'Sedimentology'

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Boya, Duocastella Salvador. "El sistema deltaico de la Arenisca de Sabiñánigo y la continentalización de la cuenca de Jaca." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/665452.

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La cuenca de Jaca representa un ejemplo excepcional de relleno sedimentario de una cuenca piggyback. Su registro estratigráfico muestra la evolución desde la sedimentación marina profunda durante el Eoceno inferior, hasta la irrupción de ambientes transicionales y continentales que evidencian la colmatación de la cuenca durante el Eoceno superior y Mioceno. Estas características, y la calidad de sus afloramientos ha convertido a esta cuenca en un análogo de referencia en los estudios de geología sedimentaria. En esta tesis se ha realizado una revisión de las formaciones deltaicas y aluviales de la cuenca de Jaca, definidas previamente en base a criterios descriptivos, con el objetivo de establecer sistemas deposicionales de carácter genético a partir de indicadores a escala de cuenca. Para ello se ha aplicado una metodología fundamentada elaboración de una cartografía geológica y el análisis de facies, este último, focalizado especialmente en las unidades deltaicas relacionadas con el sistema deltaico de la Arenisca de Sabiñánigo. Mediante la combinación de ambas técnicas se han diferenciado 8 sistemas deposicionales en la cuenca de Jaca. Entre estos 8 sistemas deposicionales destacan los sistemas deposicionales deltaicos (Bartoniense a Priaboniense) los cuales presentan cierta complejidad debido a la desconexión física presente en la cuenca entre el sector de Jaca y Fiscal. A partir de la integración de los datos estratigráficos de campo obtenidos en esta tesis, con datos paleomagnéticos y bioestratigráfico presentes en la literatura, se ha podido establecer una equivalencia entre los sistemas deltaicos en el sector de Jaca central (parte central de la cuenca) y los del sector de Fiscal (parte oriental de la cuenca). Dichas equivalencias, permiten establecer una nueva correlación entre ambos sectores con la que se asume un rango de edades más jóvenes para las unidades de Fiscal. El estudio de los sistemas deposicionales deltaicos se ha centrado en detalle en el sistema deltaico de Sabiñánigo, cuya excelente calidad en cuanto a exposición, conexión y extensión de sus afloramientos, ha permitido elaborar un estudio de facies exhaustivo. El análisis de facies ha permitido caracterizar dicho delta como un delta dominado por avenidas fluviales a partir de flujos hiperpícnicos de procedencia norte que dominan el sector de Jaca central. Durante los periodos transgresivos, los sedimentos hiperpícnicos muestran retrabajamiento por procesos mareales desarrollando sistemas de barras mareales. De manera coetánea en el sector de Fiscal, se desarrolla el sistema deltaico de San Felices Superior, caracterizado como un sistema dominado por inercia. Este sistema con procedencia este interacciona con los sistemas de procedencia norte en el sector de Jaca. Dicha interacción se manifiesta en los sedimentos mareales donde se han observado señales petrográficas de procedencia este, también por la presencia de sedimentos de plataforma externa en el flanco sur del anticlinal de Basa. Por último, se ha podido documentar un control tectónico en la ciclicidad deltaica de estos sistemas. Por un lado, el sistema deltaico de Sabiñánigo muestra estratos de crecimiento atribuibles a la actividad del cabalgamiento de Otúria. De igual manera, el sistema deltaico de San Felices Superior muestra estratos de crecimiento en su extremo oriental relacionados con el anticlinal de Boltaña. Los episodios activos de cada una de estas estructuras producen una alteración de carácter local en el espacio de acomodación, generando episodios de transgresión forzada en los sistemas deltaicos. En este trabajo se resalta el valor del análisis detallado de facies como herramienta clave para interpretar los diferentes factores que influyen en la arquitectura de los sistemas sedimentarios en un contexto tectónico activo, como la cuenca Surpirenaica. Además, esta tesis presentar el sistema deltaico de Sabiñánigo como un excelente análogo de campo de un delta dominado por avenidas.
The Jaca basin is an exceptional example of sedimentary infill of a piggyback basin. Its stratigraphic record shows the evolution from deep-marine environments during the lower Eocene until the its evolution to the transitional and terrestrial environments that represent de last stage of the basin fill during the upper Eocene-Miocene. This features, and the excellent exposure of the outcrops, allow to highlight this basin as an excellent analog in many studies related to sedimentary geology. In this thesis, a review of the delta and alluvial formations of the Jaca basin, classically defined in a descriptive sence, has been carried out in order to establish genetic depositional systems based on basin scale indicators. In order to achieve this goal a methodology based on the elaboration of a geological cartography and facies analysis has been applied, this last one, focused chiefly on the deltaic units related to the Sabiñánigo Sandstone delta system. Through the combination of both techniques, 8 depositional systems have been differentiated in the Jaca basin. Among these 8 depositional systems, the deltaic depositional ones (Bartonian to Priabonian) stand out as complex systems due the present-day lack of physical correlation in the basin between the Jaca and Fiscal sectors. From the integration of stratigraphic field data obtained in this thesis, with paleomagnetic and biostratigraphic data from the literature, it has been possible to establish an equivalence between the deltaic systems in the central Jaca sector (central part of the basin) and those of the Fiscal sector (eastern part of the basin). These equivalences allow establishing a new correlation between both sectors which allows to propose younger age range for the Fiscal units. Deltaic depositional systems analysis has been here focused in more detail on the Sabiñánigo Sandstone delta system, whose excellent quality in terms of exposure, connection and extension of its outcrops, has allowed to carry out an exhaustive facies study. Facies analysis has permitted to characterize this delta as a flood-dominated delta derived from hyperpycnal flows sourced from the north of the Jaca basin. During transgressive periods, the hyperpycnal sediments where reworked by tidal processes which developed systems of tidal bars. Synchronously, in the Fiscal sector, the upper San Felices delta system was formed as an inertia dominated delta. This system, with an eastern provenance signal, interacted with the north-derived deltas in the Jaca sector. This interaction is displayed by the recording of an eastern provenance signal in the tidal sediments, and also by the occurrence of outer shelf deposits in the southern flank of the Basa anticline. Finally, it has been possible to identify a tectonic control in the deltaic cyclicity of these systems. The deltaic system of Sabiñánigo shows growth strata which can be linked to the activity of the Otúria thrust. In the same way, the upper San Felices delta system shows growth strata in its eastern edge related to the growth of the Boltaña anticline. The active stages of each of these structures produced an alteration in the accommodation rate, generating episodes of forced transgression in the deltaic systems. In this work, the importance of detailed facies analysis is highlighted as a key tool to infer the different factors that can modify the architecture style of sedimentary systems in an active tectonic context, such as the South Pyrenean basin. In addition, this thesis presents the deltaic system of the Sabiñánigo Sandstone delta system as an excellent field analog of a flood dominated.

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Speranza, Flavio Cesar. "Variabilidad paleoclimática y cambios paleoambientales en la región Chaqueña semiárida Argentina." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670872.

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Els estudis paleoclimàtics i paleoambientals de l'holocè proporcionen informació rellevant sobre les tendències climàtiques a llarg termini necessàries per generar i provar hipòtesis sobre patrons i models climàtics, i per entendre els canvis ambientals recents. Si bé hi ha un nombre creixent d'aquests tipus d'estudis a Amèrica de Sud, encara hi ha extenses regions que no compten amb estudis detallats i d'alta resolució, tal com succeeix en el Chaco semiàrid. El present treball constitueix una aportació significativa per reduir la bretxa espacial d'informació sobre la variabilitat paleoclimàtica, la dinàmica del paisatge, i la transformació paleoambiental, a diferents escales espacials i temporals durant els últims segles a la regió semiàrida del Chaco argentí, mitjançant la vinculació i articulació d'una quantitat i diversitat significatives d'indicadors. Es van dur a terme estudis fluviomorfològics, geomorfològics, i seqüències sedimentàries mineralògiques i texturals de paleolits a la conca baixa del riu Bermejo, principal modelador del paisatge de la plana chaqueña semiàrida; anàlisis de registres multiparamètrics sedimentològics d'alta resolució (litologia, geoquímica, mineralogia) i palinològics de sediments lacustres de la Laguna Yema; construcció i anàlisis de cronologies de gruixos d'anells de l'espècie arbòria Schinopsis lorentzii, situats en un gradient latitudinal (Nord-Sud) a la regió chaqueña semiàrida d'Argentina i, complementàriament, es van emprar bases de dades d'estacions meteorològiques i hidrométriques de l'àrea d'estudi. Els nostres resultats i interpretacions constitueixen eines per ser emprades en la gestió integrada de recursos hídrics a la regió chaqueña semiàrida, on la deficiència en la disponibilitat d'aigua per la producció i consum humà i les inundacions són unes de les principals amenaces de la regió. Addicionalment, el nostre treball constitueix una entrada per a la gestió de l'ordenament ambiental i productiu del territori, on l'avanç de la frontera agropecuària per al desenvolupament de cultius extensius és el principal fenomen de canvi en la cobertura de terra, sent la seva sostenibilitat altament depenent de les variacions i estacionalitat climàtica.
Los estudios paleoclimáticos y paleoambientales del holoceno proporcionan información relevante sobre las tendencias climáticas a largo plazo necesarias para generar y probar hipótesis sobre patrones y modelos climáticos y entender los cambios ambientales recientes. Si bien hay un número creciente de este tipo de estudios en América del Sur, todavía existen extensas regiones que no cuentan con estudios detallados y de alta resolución, tal como sucede en el Chaco semiárido. El presente trabajo constituye un aporte significativo para reducir la brecha espacial de información de la variabilidad paleoclimática, la dinámica del paisaje y la transformación paleoambiental, a distintas escalas espaciales y temporales, durante los últimos siglos en la región semiárida del Chaco argentino, mediante la vinculación y articulación de una significativa cantidad y diversidad de indicadores. Se llevaron a cabo estudios fluviomorfológicos, geomorfológicos y secuencias sedimentarias mineralógicas y texturales de paleocauces en la cuenca baja del río Bermejo, principal modelador del paisaje de la llanura chaqueña semiárida; análisis de registros multiparamétricos sedimentológicos de alta resolución (litología, geoquímica, mineralogía) y palinológicos de sedimentos lacustres de Laguna Yema; construcción y análisis de cronologías de ancho de anillos de la especie arbórea Schinopsis lorentzii, ubicados en un gradiente latitudinal (Norte-Sur) en la región chaqueña semiárida de Argentina y, complementariamente, se emplearon bases de datos de estaciones meteorológicas e hidrométricas dispuestas en el área de estudio. Nuestros resultados e interpretaciones constituyen herramientas para ser empleadas en la gestión integrada de recursos hídricos en la región chaqueña semiárida, en donde la deficiencia en la disponibilidad de agua para la producción y consumo humano y las inundaciones son unas de las principales amenazas de la región. Adicionalmente, nuestro trabajo constituye un insumo para la gestión del ordenamiento ambiental y productivo del territorio, en donde el avance de la frontera agropecuaria para el desarrollo de cultivos extensivos es el principal fenómeno de cambio en la cobertura del suelo, siendo su sustentabilidad altamente dependiente de las variaciones y estacionalidad climática.
Paleoclimatic and paleoenvironmental studies of the Holocene provide relevant information regarding climatic trends in the long-term, necessaries to generate and test hypothesis on climatic patterns and models, as well as understanding recent environmental changes. While an increasing number of these type of studies are being developed in South America, there are still large regions that do not have detailed and high resolution studies, as in the case of the semi-arid Chaco. This work constitutes a significant contribution in order to reduce the spatial information gap regarding paleoclimatic variability, landscape dynamics, and paleoenvironmental transformations, at different spatial and temporal scales, during the last centuries in the semi-arid region of Argentinian Chaco, through the linkage and articulation of a significant amount and diversity of indicators. A series of studies were conducted, including fluvialmorphological, geomorphological, and textural and mineralogical sedimentary sequences in the lower basin of the Bermejo River, the main landscape modeler of the semi-arid plains in Chaco; analysis of multi-parametric sedimentological records of high-resolution (lithology, geochemistry, mineralogy) and palynological from lake sediments in Laguna Yema; construction and analysis of tree-ring width chronologies of Schinopsis lorentzii, mainly located in an altitudinal gradient (North-South) of the semi-arid Chaco region in Argentina and, as a complement, databases from meteorological and hydrometric stations arranged in the study are were also consulted. Our results and interpretations constitute tools to be employed in the integrated management of hydric resources in the semi-arid Chaco, where deficiency in water availability for production and human consumption, as well as floods, are one of the main threats in the region. In addition to that, our investigation constitutes an input for the environmental and productive management of the territory, where the advance of the agricultural border for the development of extensive crops is the main change phenomenon in soil coverage, with a sustainability highly dependent of climatic variations and seasonality.

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Menezes, Priscila Melo Leal. "Análise de fácies e proveniência sedimentar em sambaquis do litoral centro-sul de Santa Catarina." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-19082009-102541/.

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Os sambaquis do litoral sul brasileiro são marcos paisagísticos, com valor histórico e científico. Constituem-se, predominantemente, de conchas de moluscos e sedimentos com marcante presença de matéria orgânica, empilhados em conformações estratigráficas variadas. Neste trabalho, elegeram-se como objetos de estudo três sambaquis da costa centro-sul de Santa Catarina, com dois tipos de conformações distintas: de um lado, os sambaquis Carniça III e Encantadas III, e, de outro, o Jabuticabeira II, maior e estratigraficamente mais complexo. A proposta é auxiliar na reconstrução dos hábitos e costumes dos povos que viveram nesta área litorânea durante grande parte do Holoceno pré-descobrimento, e inferir suas relações com a evolução do ambiente geológico que os cercava. Para isso, foca-se em duas metas ou objetivos maiores: a aplicação de análise de fácies e de arquitetura deposicional nos sambaquis selecionados; e a investigação do uso de sedimentos paleolagunares como seu material construtivo. Para buscar estes objetivos, utilizou-se uma abordagem multi-analítica, que compreendeu: análise de fácies; determinação dos teores de matéria orgânica e carbonatos mais fosfatos; caracterização da fração grossa por lupa; granulometria; mineralogia de grãos pesados; estudo petrográfico e micromorfológico em seção delgada; microscopia eletrônica de varredura; e geoquímica e isotopia de carbono e nitrogênio. A estratigrafia dos sambaquis Carniça III e Encantada III é composta por um núcleo arenoso sobreposto por camada preta orgânica rica em conchas e artefatos antrópicos (terra preta, codificada como fácies LA). Em contraste, o sambaqui Jabuticabeira II caracteriza-se pela intercalação entre camadas conchíferas e lâminas pretas contendo sepultamentos (fácies funerária, codificada como Lc), capeada por camada de terra preta, rica em artefatos e sepultamentos. Por meio da análise de fácies, foi possível distinguir neste sambaqui três associações, da base para o topo: cascalho-lamosa, areno-lamosa e cascalho-arenosa. A sucessão vertical destas associações reflete o assoreamento progressivo do sistema lagunar e configura assim a relação do sambaqui com o ambiente deposicional do entorno. As associações de fácies, de qualquer hierarquia, são delimitadas pelas lâminas da fácies Lc. As análises do material construtivo utilizado nos sambaquis indicaram proveniência a partir das feições deposicionais mais próximas aos sítios, representadas por fundo, margem e brejo lagunar, nos casos dos sambaquis Jabuticabeira II e Encantada III, e por cordões litorâneos lagunares e dunas eólicas superimpostas, no caso do sítio Carniça III. Os parâmetros granulométricos e os índices de minerais pesados revelaram controle sobretudo geográfico em sua distribuição. A análise de componentes fosfáticos aliados aos sinais isotópicos do carbono e nitrogênio indicam grande processamento antrópico no material constituinte das lâminas funerárias e da terra preta do sambaqui Jabuticabeira II, com características de matéria orgânica putrefata, provável refugo do processamento cotidiano dos sambaquieiros. Já para o Carniça III e Encantada III, este processamento teria sido muito menor.
The sambaquis (also known as shell mounds or shell middens) in the Brazilian southern coast are landscape references and bear historical and scientific value. They are predominantly constituted of mollusk shells and sediments and also hold a sound presence of organic matter, piled up in different stratigraphic configurations. In this work, three sambaquis in the central-southern coast of the Santa Catarina state have been chosen as objects of study. They present two distinct configuration types: on one hand, the Carniça III and the Encantadas III, and, on the other hand, the Jabuticabeira II, which is larger and stratigraphically more complex. The proposal is to assist on the reconstruction of habits and traditions of the people who lived in this coastal area during a great part of the Holocene period (before the Portuguese navigators arrived in Brazil in 1500), and to infer their relations with the evolution of the surrounding geological environment. Two main goals have been set for this purpose: the application of facies analysis and depositional architecture in the selected sambaquis; and the investigation of the use of sediments from paleo-lagoons as their construction material. In order to achieve these goals, a multi-analytical approach has been used comprising: facies analysis; quantity evaluation of organic matter and carbonates associated with phosphates; characterization of the thick fraction in stereomicroscope; granulometry; heavy grains mineralogy; petrographic and micromorphological study of the thin section; scanning electron microscopy (SEM); and both carbon and nitrogen geochemistry and isotopy. The stratigraphy of the Carniça III and Encantada III sambaquis is composed of a sandy nucleus covered with a black organic layer full of shells and anthropic artifacts (black soil, represented as LA facies). In contrast, the Jabuticabeira II sambaqui is characterized by an assorted sequence of shell layers and thin black layers containing burial remains (funerary facies, represented as Lc) covered by black soil, and full of artifacts and burials. According to the facies analysis results, three associations have been found in this sambaqui, from bottom to top: muddy-gravel, muddy-sand and sandy-gravel. The vertical sequence of these associations reflects the progressive aggradation of the lagoon system and it establishes, thus, the relation between the sambaqui and the surrounding depositional environment. The facies associations, in any hierarchy, are limited by the thin layers in the Lc facies. The analysis of the construction materials used in the sambaquis has set their provenance in the nearest depositional features to the sites, represented by the lagoon bottom, margin and swamp for the Jabuticabeira II and Encantada III sambaquis, and by coastal lagoon barriers and superimposed wind dunes for the Carniça III site. The granulometric parameters and the heavy minerals indexes have showed control, mainly geographic, in their distribution. The analysis of phosphate components associated with the carbon and nitrogen isotopic signals shows great anthropic processing in the material which constitutes the funerary and the black soil layers found in the Jabuticabeira II sambaqui, with putrid organic matter characteristics, a probable waste from the day-by-day processing of the people who built the sambaquis. On the contrary, this kind of processing is supposed to have been much lower in the Carniça III and the Encantada III sambaquis.

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Rossi, Adriana Rost. "Caracterização paleoambiental a partir dos componentes orgânicos particulados em depósitos bioturbados do Bloco Central da Jazida Carbonífera do Iruí (Cachoeira do Sul, RS)." Universidade do Vale do Rio do Sinos, 2008. http://www.repositorio.jesuita.org.br/handle/UNISINOS/2191.

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A análise integrada entre a sedimentologia e a paleoicnologia da Formação Rio Bonito e da base da Formação Palermo (bacia do Paraná) na região de Cachoeira do Sul (RS) vem demonstrando a presença de depósitos flúvio-estuarinos dominados por marés na porção inferior da Formação Rio Bonito, passando a estuarinos dominados por ondas no topo e rapidamente dando lugar a depósitos marinhos rasos (base da Formação Palermo). Visando validar e, se possível, refinar essas interpretações, foi realizada uma análise paleopalinológica de alta resolução dos depósitos bioturbados. Para tanto, foram selecionadas 26 amostras nos testemunhos de sondagem IC-07-RS, IC-44-RS, IC-03-RS e IC-12-RS, pertencentes ao bloco central da jazida carbonífera de Iruí (Cachoeira do Sul, RS), quando da análise paleoicnológica. Das amostras inicialmente coletadas, foram utilizadas para a análise paleopalinológica apenas as de natureza pelítica, de forma a homogeneizar possíveis disparidades na assembléia orgânica decorrentes de granulometri
The integrated analysis of sedimentology and paleoichnology of the Rio Bonito Formation and the lower part of Palermo Formation (Paraná Basin) in Cachoeira do Sul region (Rio Grande do Sul State, south Brazil) revealed that the Rio Bonito Formation are characterized at the base by tide-dominated fluvio-estuarine deposits, changing upward to wave-dominated estuarine deposits, which are overlapped by the shallow marine deposits of the Palermo Formation. With the aim of refine such interpretations, a high-resolution paleopalynologic analysis of the bioturbed deposits is conducted in this study. Thus, 26 samples were selected from the cores IC-07-RS, IC-44-RS, IC-03-RS and IC-12-RS, from the central area of the Iruí Quarry (Cachoeira do Sul). Only mudstones and siltstones samples were used for the paleopalynologic analysis, in order to homogenize possible disparities in the organic assemblage due to the grain-size. Paleopalynomorph and palynofacies samples were prepared following the traditional methods for Pa

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Sellén, Emma. "Quaternary paleoceanography of the Arctic Ocean : A study of sediment stratigraphy and physical properties." Doctoral thesis, Stockholms universitet, Institutionen för geologi och geokemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-30895.

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A Quaternary perspective on the paleoceanographic evolution of the central Arctic Ocean has been obtained in this PhD thesis by studying sediment cores from all of the Arctic’s major submarine ridges and plateaus. The included cores were mainly recovered during the Healy-Oden Trans-Arctic expedition in 2005 and the Lomonosov Ridge off Greenland expedition in 2007. One of the main thesis objectives is to establish whether different sediment depositional regimes prevailed in different parts of the central Arctic Ocean during the Quaternary and, if so, establish general sedimentation rates for these regimes. This was approached by dating key cores using the decay of the cosmogenic isotopes 10Be and 14C, and through stratigraphic core-to-core correlation using sediment physical properties. However, the Arctic Ocean sea ice complicated the use of 10Be for dating because a solid sea ice cover prevents the 10Be isotopes from reaching the seafloor, resulting in too old ages. Dating using 14C is also complicated due to uncertain marine reservoir age corrections in the central Arctic Ocean. The core-to-core correlations show five areas with different depositional regimes; the northern Mendeleev Ridge and Alpha Ridge, southern Mendeleev Ridge, Morris Jesup Rise, Lomonosov Ridge and Yermak Plateau, listed in the order of increasing sedimentation rates from ~0.5cm/ka to ~4.8 cm/ka. A detailed study of the relationship between sediment bulk density and grain sizes suggests a strong link between variations in clay abundance and bulk density. Grain size analysis of a Lomonosov Ridge core show that fine silt and clay dominates the interglacials, possibly due to increased suspension freezing of these size fractions into sea ice and/or nepheloid transport. Sediments younger than the marine isotope stage (MIS) 7 generally contain more coarse silt, attributed to a regime shift during the Quaternary with increased iceberg transport into the central Arctic Ocean from MIS 6 and onwards.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: In progress. Paper 4: In progress. Paper 5: In progress. Paper 6: In progress.

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Tognoli, Francisco Manoel Wohnrath [UNESP]. "Estratigrafia das seqüências deposicionais do grupo Guatá, borda leste da Bacia do Paraná." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/102978.

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O Grupo Guatá foi alvo de um estudo detalhado ao longo de toda a borda leste da Bacia do Paraná. Por meio da análise e descrição seqüencial de testemunhos e integração com dados de perfis, aproximadamente 100 poços foram analisados desde o norte do Estado do Paraná até a região centro-sul de Santa Catarina. As fácies foram agrupadas em sucessões de fácies, a partir das quais foram definidos os padrões de empilhamento do tipo progradante, retrogradante e agradante, que em conjunto definem os tratos de sistemas e conseqüentemente as seqüências deposicionais. Além disso, foi realizado um estudo de integração entre sedimentologia, icnologia e geoquímica, que definiu critérios para a identificação e interpretação de superfícies com significado estratigráfico regional. Isso possibilitou correlacionar com segurança poços ao longo de toda a borda leste da Bacia do Paraná e mapear a distribuição das seqüências deposicionais de 3ª.e 4ª ordens. O arcabouço estratigráfico revelou que as seqüências são formadas pelos tratos de sistemas transgressivo e de mar alto ou apenas pelo trato de sistemas transgressivo. Notou-se também que as seqüências estão diretamente vinculadas aos principais lineamentos estruturais da bacia. Interpreta-se que as seqüências 1, 2, 3, 4 e 5 foram soerguidas ao longo de toda a borda leste da Bacia do Paraná, com sua expressão máxima na região do Arco de Ponta Grossa. Esse soerguimento gerou uma discordância angular com expressão regional sobre a qual foram depositadas as seqüências 6, 7 e 8. A seqüência 8 é marcada por subsidência entre os Alinhamentos do Rio Piquiri e São Jerônimo-Curiúva, contemporânea à deposição dos tratos de sistemas transgressivo e de trato de mar alto.
The Guatá Group was target of a detailed study along the eastern border of the Paraná Basin. Using integration of core description and well logs, approximately 100 wells were analyzed in Paraná and Santa Catarina states. Facies were grouped in facies successions, which allowed the recognition of the progradational, retrogradational and aggradational stacking patterns and, consequently, system tracts and depositional sequences. Moreover, it was performed an integration among sedimentology, ichnology and geochemistry as a way to obtain criteria for identifying and interpreting regional stratigraphic surfaces. This allowed a detailed correlation along the eastern border of Paraná Basin and the mapping of third and fourth order sequences. The stratigraphic framework has revealed sequences formed either by the transgressive and highstand system tracts or just by the transgressive one. The sequences are directly linked to the main structural linements of the basin. It is interpreted that sequences 1, 2, 3, 4 and 5 were uplifted along the eastern border of the basin, with the maximum expression in the region of the Ponta Grossa Arch. An angular unconformity was generated and sequences 6, 7 and 8 were deposited later in time. Sequence 8 was affected by subsidence between the Rio Piquiri and São Jerônimo-Curiúva linements, contemporaneous to deposition of the transgressive and highstand system tracts.

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Ferreira, Manuela Pinheiro. "Geocronologia e proveniência dos sedimentos holocênicos da confluência dos rios Negro e Solimões, AM." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-14112013-102806/.

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O sistema fluvial amazônico representa a maior bacia de captação de sedimentos do mundo. Neste contexto, o objetivo deste estudo foi caracterizar as areias transportadas pelos rios Negro e Solimões e discriminar a contribuição do aporte sedimentar arenoso derivado destes dois rios para a formação do rio Amazonas. Além disso, buscou-se identificar variações temporais da geomorfologia fluvial da zona de confluência dos rios Negro e Solimões. Para tanto, foram utilizados métodos de análise geomorfológica e de fácies, granulometria, sensibilidade por luminescência opticamente estimulada (LOE) da fração areia e datações LOE e 14 C. Os sedimentos das barras do rio Negro apresentam maior porcentagem de areia, com diâmetro médio em 375,76 µm, os quais são dominados por grãos de quartzo de sensibilidade LOE moderada (3,06). Já os sedimentos das barras dos rios Solimões e Amazonas são mais finos, com diâmetro médio em 154,58 µm e 134,36 µm, respectivamente, alta porcentagem de feldspato e grãos de quartzo com baixa sensibilidade LOE (2,49 e 2,53, respectivamente). O aporte arenoso do rio Solimões (88,08% para sedimentos de calha e 98,23% para barras) sobre o rio Amazonas é dominante em relação ao aporte do rio Negro (11, 91% para sedimentos de calha e 1,76% para barras). Os dados de sensibilidade LOE sugerem que os sedimentos do rio Negro são acomodados principalmente na calha do rio Amazonas. Os arenitos da Formação Alter do Chão adjacentes ao canal do baixo rio Negro representam a principal área fonte dos sedimentos deste rio. A baixa maturidade composicional e sensibilidade LOE reduzida dos sedimentos do rio Solimões sugerem rápido transporte sedimentar a partir de áreas fontes andinas. O tempo de estocagem mínimo para as areias de barras expostas durante a seca do rio Negro varia entre 0,34±0,04 ka e 1,7±0,26 ka. Já o período mínimo de estocagem das areias em barras dos rios Solimões e Amazonas variou entre 1,3±0,21 ka e 11,9±1,18 ka. As principais fases de construção das barras dos rios Solimões e Amazonas estariam relacionadas principalmente com eventos de precipitação extrema do Holoceno.
The Amazon river system is the largest sediment catchment basin in the world. In this context, this study aims to differentiate the sands carried by the Negro and Solimões rivers and estimate the sandy sedimentary supply derived from these two rivers to the Amazon river. Furthermore, this research also deals with temporal variations of fluvial geomorphology in the confluence area of the Negro and Solimões rivers. For this purpose, we used methods of geomorphological, facies and grain size analysis coupled with optically stimulated luminescence (OSL) sensitivity of sand fraction and OSL and 14 C dating. The sediments of the Negro river bars showed a higher percentage of sand, with mean diameter of 375,76 µm, which are dominated by quartz grains with moderate OSL sensitivity (3,06). On the other hand, sediment from bars of Solimões and Amazonas rivers are thinner, with mean diameter of 154,58 µm and 134,36 µm, respectively, high percentage of feldspar and quartz grains with low OSL sensitivity (2,49 and 2,53, respectively). The contribution of Solimões river sands (98.23%) to the Amazon river is dominant in relation to the contribution of the Negro river (1.76%). OSL sensitivity data suggest that the Negro river sediments are accommodated mainly in the Amazon River channel. The Alter of Chão Formation sandstones outcropping adjacent to the lower Negro river channel area represent the main source of sediments for this sector of the Negro river. The low compositional maturity and reduced OSL sensitivity of Solimões river sediments suggest rapid sediment transport from Andean source areas. The minimum storage time for the Negro river sand bars exposed during the dry season varies between 0,34 ± 0,04 ky and 1,7 ± 0,26 ky. The minimum storage time of sands in bars from the Solimões and Amazonas rivers ranged between 1,3 ± 0,21 ky and 11,9 ± 1,18 ky. The main construction phases of the Solimões and Amazonas rivers bars would be related to extreme precipitation events during the Holocene.

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Martins, Patrícia Diniz. "Estimativa da concentração de sedimentos utilizando a teoria da entropia." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-12122016-112951/.

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A preocupação com a qualidade das águas vem promovendo o desenvolvimento de técnicas cada dia melhores de monitoramento e controle. Como os sedimentos transportam a maior parte dos contaminantes da água, seu estudo é fundamental. Diante do elevado número de variáveis existentes para a determinação da concentração de sedimentos e elevados custos de campanhas de monitoramento, torna-se necessário o desenvolvimento de métodos mais acessíveis e que tragam resultados práticos satisfatórios. Para tanto, este trabalho trata da aplicação da teoria da entropia, um método probabilístico, para determinar a concentração de sedimentos em calhas com diversas concentrações e granulometrias. Para isso, foi proposta uma relação entre os parâmetros da teoria da entropia com a finalidade de reduzir o esforço computacional. Os resultados mostraram-se satisfatórios para concentrações acima de 10 g/L com R² superiores a 0,88. Os erros quadráticos calculados neste trabalho foram inferiores aos encontrados quando utilizada a teoria da entropia por Tsallis e pela Equação de Rouse, modelos clássicos de determinação do perfil de concentração de sedimentos. A técnica também foi aplicada a jusante e no interior do Reservatório de Mogi. Pode-se observar que é possível utilizar a teoria da entropia para simular o perfil de concentração de sedimentos em reservatórios, uma vez que a utilização da relação entre os parâmetros facilita os cálculos, reduz o número de parâmetros modelados e consequentemente o esforço computacional além de representar melhor as variações da concentração de sedimentos ao longo do perfil. A aplicabilidade do modelo proposto e a facilidade da utilização do método probabilístico, já que não necessita fornecer os dados de condições hidráulicas do leito, nem mesmo de granulometria, torna-o viável.
The concern about quality of water has been promoting the development of each day better monitoring and control techniques. As sediments transport most water contaminants, their study is fundamental. Given the large number of variables for determining sediment concentration and high costs of monitoring campaigns, it becomes necessary to develop more accessible methods which bring satisfactory practical results. Therefore, this work deals with application of the theory of entropy, a probabilistic method to determine concentration of sediments in river channels with various concentrations and particle sizes. For this purpose, it was proposed a relationship between the theory of entropy parameters in order to reduce the computational effort. The results were satisfactory at concentrations above 10 g/L with R² greater than 0.88. The calculated squared errors in this study were lower than those found when using the theory of entropy by Tsallis and the equation of Rouse, classic models for determining the sediment concentration profile. The technique was also applied to downstream and inside the Mogi reservoir. It can be observed that it is possible to apply the theory of entropy to simulate sediment concentration profile of reservoirs, since the use of the relationship between parameters facilitates calculations, reduces the number of modeled parameters and consequently the computational effort as well as better represents the variation of sediment concentration along the profile. The applicability of the proposed model and the ease of using the probabilistic method, since it does not need provide data of hydraulic bed conditions not even grain size, make it feasible.

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Herries, Robert David. "Sedimentology of continental erg-margin interactions." Thesis, University of Aberdeen, 1992. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU045051.

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Modern ergs are characterized by bedform types and distributions that reflect the directional variability and result and drift potential of the wind regime. Sand accumulates in the erg-centre, an area of low resultant drift potential where large, slow-moving linear and star draas act as sediment sinks. The thickest ancient aeolian sequences contain stacked transverse and oblique draa and dry interdune deposits. Only these forms are able to transport sand rapidly enough to aggrade by autocyclic bedform climb. Subsidence probably played a crucial role in their accumulation. Todays ergs are poor analogues for ancient erg sequences due to the rapidity of recent climatic change and because they do not appear to be aggrading by bedform climb. The sand saturation concept introduced by Wilson (1971) provides a valuable tool for understanding the nature of ancient ergs and regional bounding surfaces. Undersaturated conditions cannot form dunes, but under metasaturated conditions, dunes with deflationary interdunes may be sustained, but these are incapable of preservation by bedform climb. Only under fully sand-saturated conditions can ergs aggrade by bedform climb. The presence of deflationary interdunes in ancient erg-margin sequences indicates metasaturated conditions and implies that preservation only follows subsidence or water-table rise. Two extremes or erg-margin interaction are identified here. One, the Kayenta-Navajo transition, occurred at the margin of an established erg. Fluvial-aeolian interactions form small-scale cycles that reflect the continual interplay between the active erg and adjacent fluvial system. Large-scale cycles appear to represent a climatically-controlled alternation between active and denudated erg phases, the latter allowing advance of fluvial systems over the former erg during wetter phases. The opposite extreme occurred during deposition of the Ormskirk sandstone in the Irish Sea. Here, conditions were predominantly unsaturated because, though aqueous and aeolian processes provided an abundant supply of sand, this was almost immediately removed from the aeolian system by the continually rising water-table, thus restricting erg and dunefield development to elevated areas.

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Godoy, Mario Duarte Pinto. "MudanÃas na sedimentaÃÃo no estuÃrio do rio Jaguaribe (CE) devido a mudanÃas nos usos do solo." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5972.

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O rio Jaguaribe Ã o rio com a maior bacia hidrogrÃfica do CearÃ, possui uma bacia hidrogrÃfica de 75 mil KmÂ que ocupa mais de 50% do estado, no entanto, alteraÃÃes de uso do solo que ocorreram dentro da bacia hidrogrÃfica desse rio e alteraÃÃes climÃticas globais podem estar causando a diminuiÃÃo da profundidade do estuÃrio o que dificulta a navegabilidade nessa regiÃo e prejudica a fauna aquÃtica. O foco desse estudo Ã os sedimentos depositados em ilhas dentro do baixo estuÃrio e possÃveis Ãreas no entorno que foram consideradas como possÃveis fontes de sedimento para essas ilhas. O plano amostral consistiu em 6 pontos dentro do estuÃrio do rio Jaguaribe onde foram retirados testemunho de sedimento e mais 8 pontos onde foram retirados sedimento superficiais no fundo do rio, nas Ãreas da margem e no campo de dunas. As Ãreas foram escolhidas a partir do mapeamento do estuÃrio, esse mapeamento utilizou imagens dos satÃlites Landsat 5, Quickbird II e Kompsat 2 e cobrem o perÃodo entre os anos de 1988 e 2008. O mapeamento mostrou que as ilhas existentes no estuÃrio sofreram grandes mudanÃas no perÃodo de estudo, ao todo ocorreu um aumento de 31,5 hectares na Ãrea ocupada por vegetaÃÃo de manguezal nas ilhas do estuÃrio. O perÃodo de maior crescimento foi o perÃodo entre 1992 e 2003 onde ocorreu um aumento de 6 hectares com uma velocidade de 2,1 hectare por ano. AlÃm do mapeamento foi realizada uma estimativa de carga de sedimento dos diversos usos do solo na bacia hidrogrÃfica do baixo estuÃrio, essa estimativa mostrou que as principais atividades que contribuem com sedimento para o estuÃrio Ã a agricultura (282.322 t/ano), sendo os principais contribuintes as plantaÃÃes de feijÃo, de mandioca e as de milho. Seguem-se as Ãreas urbanas (115.076 t/ano), as fazendas de camarÃo (13.475 t/ano) e a pecuÃria (1.374/ano). Ao contrÃrio de todas as outras atividades encontradas na Ãrea de estudo, o cultivo de camarÃo Ã a Ãnica atividade em que a carga de sedimento Ã lanÃada diretamente no estuÃrio. A granulometria dos testemunhos mostrou um predomÃnio de areias sobre as outras classes, alÃm disso, mostrou que em um mesmo testemunho podem existir diversos tipos de sedimento, havendo camadas com grande quantidade de silte e argila e camadas formadas basicamente de grÃos mais grosseiros, a aparÃncia semelhante com os sedimentos retirados das margens aponta as diversas Ãreas de erosÃo encontradas espalhadas pelas margens do rio como uma possÃvel fonte de grande importÃncia dentro desse contexto.
The Jaguaribe river is the river with the biggest whatershed of CearÃ and has a catchment area of 75,000 km Â which occupies over 50% of the state, however, land use changes that occurred in the watershed of this river and global climate change could be causing the decrease of the depth of the estuary which can make impossible for ship to navigate in the estuary and affect the aquatic fauna. The focus of this study is the deposited sediment in islands within the estuary and the surrounding areas which were considered as possible sources of sediment to these islands. The sampling plan consisted in 6 point within the estuary of the Jaguaribe river where were taken sediment cores and further 8 points where were taken superficial sediment from the bottom of the river, from areas in the margin of the estuary and from the dune fields near the estuary. The sampling locals were chosen based on the mapping of the estuary, this mapping used images from the satellites Landsat 5, Quickbird II and Kompsat 2 and cover the period of time between the years of 1988 and 2008. This mapping showed that the existing islands in the estuary suffered great changes during this period, overall there was an increase of 31.5 hectares in the area colonized by mangrove vegetation in the islands. The period of greatest growth was the period between 1992 and 2003 where there was an increase of 6 hectares with a speed of 2.1 hectare per year. In addition to mapping was performed an estimative of sediment load from various land uses in the watershed of the lower estuary, the estimative showed that the main activities that contribute sediment to the estuary is agriculture (282,322 t / year), with the main contribution being from plantations of beans, cassava and corn. Following are the urban areas (115,076 t / year), the shrimp farms (13,475 t / year) and livestock (1,374 t / year). Unlike all the other activities found in the study area, shrimp farming is the only activity in which the sediment load is released directly into the estuary. The diameter of the sediment from the samples showed a predominance of sand on the other classes and also showed that in a same profile may be different types of sediment, with layers with large amounts of silt and clay and layers formed primarily of coarser grains, the appearance of this sediment is similar from the sediment removed from the margin of the estuary and indicates that the several areas of erosion found scattered along the margin of the river may be possible source of great importance within this context.

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Tognoli, Francisco Manoel Wohnrath. "Estratigrafia das seqüências deposicionais do grupo Guatá, borda leste da Bacia do Paraná /." Rio Claro : [s.n.], 2006. http://hdl.handle.net/11449/102978.

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Orientador: Joel Carneiro de Castro
Banca: Ricardo da Cunha Lopes
Banca: Jorge Hachiro
Banca: Antonio Roberto Saad
Banca: José alexandre de Jesus Perinotto
Resumo: O Grupo Guatá foi alvo de um estudo detalhado ao longo de toda a borda leste da Bacia do Paraná. Por meio da análise e descrição seqüencial de testemunhos e integração com dados de perfis, aproximadamente 100 poços foram analisados desde o norte do Estado do Paraná até a região centro-sul de Santa Catarina. As fácies foram agrupadas em sucessões de fácies, a partir das quais foram definidos os padrões de empilhamento do tipo progradante, retrogradante e agradante, que em conjunto definem os tratos de sistemas e conseqüentemente as seqüências deposicionais. Além disso, foi realizado um estudo de integração entre sedimentologia, icnologia e geoquímica, que definiu critérios para a identificação e interpretação de superfícies com significado estratigráfico regional. Isso possibilitou correlacionar com segurança poços ao longo de toda a borda leste da Bacia do Paraná e mapear a distribuição das seqüências deposicionais de 3ª.e 4ª ordens. O arcabouço estratigráfico revelou que as seqüências são formadas pelos tratos de sistemas transgressivo e de mar alto ou apenas pelo trato de sistemas transgressivo. Notou-se também que as seqüências estão diretamente vinculadas aos principais lineamentos estruturais da bacia. Interpreta-se que as seqüências 1, 2, 3, 4 e 5 foram soerguidas ao longo de toda a borda leste da Bacia do Paraná, com sua expressão máxima na região do Arco de Ponta Grossa. Esse soerguimento gerou uma discordância angular com expressão regional sobre a qual foram depositadas as seqüências 6, 7 e 8. A seqüência 8 é marcada por subsidência entre os Alinhamentos do Rio Piquiri e São Jerônimo-Curiúva, contemporânea à deposição dos tratos de sistemas transgressivo e de trato de mar alto.
Abstract: The Guatá Group was target of a detailed study along the eastern border of the Paraná Basin. Using integration of core description and well logs, approximately 100 wells were analyzed in Paraná and Santa Catarina states. Facies were grouped in facies successions, which allowed the recognition of the progradational, retrogradational and aggradational stacking patterns and, consequently, system tracts and depositional sequences. Moreover, it was performed an integration among sedimentology, ichnology and geochemistry as a way to obtain criteria for identifying and interpreting regional stratigraphic surfaces. This allowed a detailed correlation along the eastern border of Paraná Basin and the mapping of third and fourth order sequences. The stratigraphic framework has revealed sequences formed either by the transgressive and highstand system tracts or just by the transgressive one. The sequences are directly linked to the main structural linements of the basin. It is interpreted that sequences 1, 2, 3, 4 and 5 were uplifted along the eastern border of the basin, with the maximum expression in the region of the Ponta Grossa Arch. An angular unconformity was generated and sequences 6, 7 and 8 were deposited later in time. Sequence 8 was affected by subsidence between the Rio Piquiri and São Jerônimo-Curiúva linements, contemporaneous to deposition of the transgressive and highstand system tracts.
Doutor

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Flathers, Joshua. "The Role of Basin Configuration and Allogenic Controls on the Stratigraphic Evolution of River Mouth Bars." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2462.

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Deltas are important coastal systems throughout the world. River mouth bars are key landforms in the development of deltas, are characterized by sediment deposition, and have high potential for sediment preservation. Scientists and professionals seek to understand the discrete response of mouth bars to the various controls governing their evolution. This study utilizes the numerical modelling software Delft3D to provide additional evidence supporting the morphological and stratigraphic responses resulting from variations in basin configurations and allogenic controls (fluvial discharge, tides, basin width). Mud content within the bar increased analogous to an increase in the tidal modulation, while a decrease in the initial basin depth reduced mud content. Initial basin slope and lateral confinement had less obvious impacts on stratigraphy. Finally, variable fluvial discharge and the incorporation of realistic tidal harmonics produced similar bar morphologies (compared to simulations with constant flow and sinusoidal tides), yet demonstrated significant differences in bar stratigraphy.

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Farvardini, Mandana. "The Sedimentological Distribution of Upper Brent, Oseberg field, North Sea." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-312874.

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The Oseberg hydrocarbon field is located in the northern North Sea sedimentary basin (61-62° N) on the eastern flank of the Viking Graben and is bounded to the east by the Horda Platform and the Øygarden Fault Complex (ØFC). The field is covering up most parts of block 30/6 and 30/9 on the Norwegian Continental Shelf (NOCS) but also minor parts of blocks 30/5, 30/8 and 30/12. The North Sea has developed through a very complex structural setting thus a great effect on the Oseberg hydrocarbon field where good quality sandstone reservoir rocks have been able to deposit very successively. The structural event of the Mid North Sea dome that occurred in the Middle Jurassic (Bajocian-Bathonian) is considered to be a main source of the successive sedimentary formations that the Oseberg field is buildup on. These formations are mainly a part of the Brent Group which consists of five lithological formations; Brent, Rannoch, Etive, Ness and Tarbert, where the Ness and Tarbert formation are representing great sandstone reservoir rocks. The study of structural and stratigraphic frameworks of the Oseberg field and its formations will help predict depositional environments thus evaluate reservoir systems. Fairly good results of lithology interpretation will be provided through analyzing well log-, and core-data and with seismic supplies, even stronger results. Keywords: Sedimentology, Middle Jurassic, Brent Group, paleoenvironment, petroleum geology

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Millson, John Alan. "The sedimentology of the Celtic Sea Jurassic." Thesis, Cardiff University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303025.

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Siqueira, Eliane de. "\"História ecológica da floresta de Araucária durante o Quaternário Tardio no setor sul da serra da Mantiqueira: análises sedimentológicas e palinológicas na região de Monte Verde (MG)\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/44/44140/tde-21032007-145459/.

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A baixa temperatura média anual (< 18ºC), a localização em zona de altitude elevada (> 1500 m) e a diversidade florística, bem representativa da parte sul da serra da Mantiqueira, tornam a região de Monte Verde (município de Camanducaia, sudeste do Estado de Minas Gerais), propícia para a investigação de mudanças climáticas ocorridas no Quaternário tardio, meta desta Dissertação. Para buscar esta meta, propõe-se como objetivo a análise e descrição da sucessão paleoflorística, integrada ao aporte sedimentar e às condições geoquímicas de deposição nesta região, com base de dados palinológicos, sedimentológicos (granulometria, concentração de matéria orgânica e teor e tipos de minerais pesados) e geocronológicos (datações 14C por espectrometria de aceleração de massa). A área amostrada foi a margem esquerda do Córrego dos Cadetes, afluente do rio Jaguari. Trata-se de um vale fluvial encaixado em alvéolo de relevo acidentado, onde se coletou testemunho raso (2,10m) contínuo, com equipamento vibrocorer (vibro-amostrador). Os depósitos sedimentares tertemunhados são argilo-arenosos orgânicos e turfosos. Sua análise sedimentológica demonstra a ocorrência de variações graduais e cíclicas relacionadas a mudanças no balanço entre aporte sedimentar terrígeno e biodretítico e/ou orgânico, controlado por alterações no tipo de processo deposicional, e, por extensão, na cobertura vegetal, esta possivelmente influenciada por oscilações climáticas do Quaternário Tardio. As cinco datações obtidas ficaram compreendidas no intervalo entre 20830-20370 anos 14C cal A.P. (100 cm de profundidade) e 2350?2150 anos 14C cal A.P. (10 cm). Os dados palinológicos permitem interpretar que durante todo esse período a região foi dominada por floresta, principalmente com a presença de Araucaria angustifolia, sob clima predominantemente frio e úmido, porém com possíveis oscilações de umidade. Para efeito de inferências paleoclimáticas, quatro fases principais foram identificadas, expressas a seguir em idades extrapoladas. A primeira fase corresponde ao intervalo de 17000 a 15000 anos A.P., no qual há oscilação da cobertura vegetal e aumento de erosão nas encostas, sob clima frio e úmido. Na segunda fase, de 15000 a 9000 anos A.P., detectou-se aumento de umidade acompanhado da redução do aporte trativo. A terceira fase, correspondente ao intervalo de 9000 a 8000 anos A.P., registra decréscimo na umidade e aumento da taxa de sedimentação. Nos últimos 8000 anos A.P., ocorre a manutenção da floresta de Araucaria em condições climáticas frias e úmidas.
Low annual average temperature (< 18ºC), the localization in a zone of high altitude (> 1500 m) and high floristic diversity, representative of the southern part of the Serra da Mantiqueira highlands, turn the Monte Verde region (city of Camanducaia, Southeast of the State of Minas Gerais), propitious for the inquiry of Late Quaternary climatic changes, the aim of this dissertation. The objective of the study is to analyze and describe the paleofloristic succession based on palynology, integrated with sedimentological (grain size and heavy mineral analysis), geochemical (quantification of organic matter) and geochronological (14C AMS dating) data. The sampled area is located at the left margin of the Cadetes stream, a tributary of the Jaguari River. A 2.10 m long sediment core was collected on the fluvial valley with a vibrocore equipment. The sandy-clay sediments show a high organic content and are similar in appearance to peatbog deposits. The sedimentological analysis demonstrate the occurrence of gradual and cyclic variations related to the change in incoming of terrigenous biodetrital/organic sediments, controlled by alterations in the type of depositional process, and, therefore, possibly by the vegetation cover. All these changes were possibly influenced by climatic oscillations of the Late Quaternary. The five 14C AMS dates obtained encompass the period between 20830-20370 14C cal. A.P. (100 cm of depth) and 2,350-2,150 years 14C cal. A.P. (10 cm). The palynological results indicate that in the last 20,000 years the landscape was characterized by Araucaria angustifolia forest under predominantly cold and humid climates, with minor oscillations of humidity. Four pollen phases had been identified, with extrapolated ages for paleoclimatic inferences. The first one corresponds to the interval between 17,000 and 15,000 years A.P. with oscillation of the forest cover under cold and humid climate. Between 15,000 and 9,000 years A.P., there is an increase of humidity and reduction of tractive sedimentary supply. The third interval corresponds to the period between 9,000 and 8,000 years A.P. with a decrease in humidity and increase of the sedimentation rate. In the last 8,000 years A.P. Araucaria forest was maintained under cold and humid climatic conditions, as it did during the Late Pleistocene.

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Junior, Daniel Rodrigues do Nascimento. "Evolução sedimentar holocênica do delta do rio Tubarão, Estado de Santa Catarina." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-26072011-145300/.

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O delta do rio Tubarão, situado na costa centro-sul catarinense entre os municípios de Tubarão, Jaguaruna e Laguna, constitui raro exemplo de delta lagunar ativo no Brasil. Sua planície deltaica cobre área aproximada de 250km2, onde são encontradas evidências de migração de canais fluviais dadas por séries de truncamentos de antigos distributários, alguns ainda ativos. Dez testemunhos foram obtidos junto aos principais canais distributários do rio Tubarão, a partir dos quais foram realizadas análises de fácies, granulométrica, de minerais pesados, de teor de matéria orgânica e de relações químio-isotópicas, além de datações 14C. Também foram levantados acervos históricos de fotografias aéreas e de dados de prospecção mineral de subsuperfície. Cerca de 5000 anos atrás, na região de seu ápice, próximo ao rio tributário Capivari de Baixo, o delta do rio Tubarão ingressou numa antiga baía lagunar e ramificou-se em sete distributários principais que, desde seus momentos iniciais de migração, foram controlados por avulsões autogênicas rumo a antigas depressões do fundo da bacia receptora. Tais avulsões progradaram o delta inicialmente para SW, depois para ENE, e então para NNE, favorecendo a fragmentação da antiga baía lagunar em uma série de lagos e lagunas menores. Diante deste cenário dinâmico, sambaquis foram erigidos no entorno do sistema lagunar, constituindo importantes registros arqueológicos de interação entre evolução sedimentar e ocupação humana pré-histórica. O resultado das análises granulométricas indicou que a sedimentação deltaica, nas proximidades de encostas de morros, foi misturada com colúvio e/ou depósitos de fluxos gravitacionais, como evidenciado pela presença de intervalos texturalmente muito imaturos em alguns testemunhos. Em relação à análise de minerais pesados, o principal fator de controle nas variações da assembleia em depósitos de delta e de bacia é a proveniência sedimentar. Em termos mediatos, essa proveniência reflete fontes plutônicas e metamórficas (médio a alto grau) do Batólito de Florianópolis (e xenólitos associados) e do Complexo Granito-Gnáissico, e rochas arenáceas alteradas da Bacia do Paraná. Em termos imediatos, depósitos deltaicos destacam-se pela afinidade mineralógica com as areias do rio Tubarão, inferida sobretudo a partir da presença mútua de grãos alterados de cianita e estaurolita, enquanto que depósitos da bacia lagunar destacam-se por sua similaridade mineralógica com areias dos rios tributários Braço do Norte e Capivari de Baixo, neste caso principalmente pela presença de zircão. A matéria orgânica presente nos depósitos do delta e de sua bacia receptora resulta do aporte de fontes terrestres (fornecido pelos rios) e marinhas (trazido via desembocaduras lagunares), fato que é evidenciado pelos resultados de \'delta\'\'POT.13 C\', \'delta\'\'POT.15 N\' e razão \'C IND.ORG\'/\'N IND.TOTAL\'. Particularmente, nos sedimentos da bacia, variações entre diferentes tipos de matéria orgânica têm ocorrido ao longo do Holoceno, as quais são atribuídas tanto ao isolamento físico progressivo do sistema lagunar em relação ao mar aberto como por mudança climática regional (aumento destacado de precipitação). A análise isotópica de oxigênio (\'delta\'\'POT 18 O\') de conchas de moluscos em depósitos da bacia indicou enriquecimento relativo em \'ANTPOT.16 O\' durante o Holoceno. Este resultado, a exemplo daquele dos isótopos de carbono e de nitrogênio dos sedimentos, sugere isolamento gradual das águas lagunares em relação às de mar aberto.
The Tubarão river delta, located on the centre-south coast of Santa Catarina State, among the municipalities of Tubarão, Jaguaruna and Laguna, is rare example of active lagoonal delta in Brazil. Its delta plain covers an area of about 250km2, where there are evidences of migration of fluvial channels in a set of truncations of ancient distributaries, some of these still in activity. Ten cores were acquired adjacent to the main distributary channels of the Tubarão river, from which analyses of facies, grain size, heavy minerals, organic matter, chemistry-isotope ratios, and radiocarbon datings were performed. Also, aerial photographies and data of subsurface mining were surveyed from historical collections. Thereabout 5,000 years ago, in the region of its apex, near Capivari de Baixo tributary river, the Tubarão river delta entered an ancient lagoonal bay and branched seven main distributaries. Since the beginning of its migration, these distributaries were controlled by autogenic avulsions towards ancient depressions in the bottom of the basin. Initially, these avulsions prograded the delta towards SW, afterwards to ENE, and then to NNE, favoring the fragmentation of the ancient lagoonal bay in a set of smaller lakes and lagoons. Faced with this dynamical scenario, shellmounds were erected surrounding the lagoon system, composing important archaeological records of the interaction between sedimentary evolution and prehistoric human occupation. The results of the grain size analysis showed that the deltaic sedimentation, in the vicinity of slopes of hills, was mixed with colluvium and/or gravity flow deposits, that is evidenced by the presence of texturally very immature intervals in some cores. The analysis of heavy minerals, by its turn, showed that the main controlling factor in the variations of its assemblage in deposits of delta and basin is the sedimentary provenance. In terms of mediate sources, this provenance reflects plutonic and metamorphic (medium to high grade) rocks of the Florianópolis batholith (including its xenoliths) and of the Granite-Gneiss Complex, and weathered sedimentary sandstones of the Palaeozoic Paraná basin. Regarding immediate sources, deltaic deposits stand out by its mineralogical affinity with sands of the Tubarão river, mainly by the mutual presence of weathered grains of kyanite and staurolite, whereas deposits of the lagoon have mineralogical similarity with the sands of Braço do Norte and Capivari de Baixo tributary rivers, especially in relation to the presence of zircon. The origin of the organic matter found in the deposits of the delta and in its lagoonal basin is both from sedimentary input of terrestrial sources (provided by rivers) and marine (brought via inlets), fact evidenced by results of \'delta\'\'POT.13 C\', \'delta\'\' POT.15 N\', and \'C IND.ORG\'/\'N IND. TOTAL\' ratio. Particularly, in the sediments of the basin, variations between different types of organic matter have occurred during the Holocene, and are attributed both to the progressive physical isolament of the lagoon system from the open sea, and by local climate change (pronounced augment of precipitation). The isotope analyses of oxygen (\'delta\'\'POT.18 O\') of molluskan shells from the deposits of the basin present relative enrichment in \'ANTPOT.16 O\' during the Holocene. This result, as well as the one from isotope analyses of carbon and nitrogen of sediments, suggests gradual isolation of the lagoonal waters of influence of waters from the open sea.

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17

Ramos, Ordoño Adrià. "Post-Hercynian tectonic and paleogeographic evolution of SW Iberia and the Gulf of Cadiz." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/436893.

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This thesis addresses the tectonic and paleogeographic evolution of the SW Iberia Margin from the Mesozoic rifting stage to the post-rifting collision of Late Cretaceous through Miocene times and transpressive stages of Pliocene and Quaternary. The study is based on onshore field work, and analysis of well logs, a large set of 2D and 3D seismic reflection profiles and gravity data of the offshore. The main contribution of this thesis is to provide an integrated model for the Mesozoic evolution of the Algarve Basin taking into account the main factors that affected the its configuration, such as the stratigraphic record, crustal structure, salt tectonics, rifting and compressional deformation. At present, the SW Iberian margin is located along the convergent Nubia-Iberia plate boundary. In Mesozoic times, this passive margin was located to the northeast of the triple junction of the Ligurian Tethys, Central Atlantic and Northern Atlantic. Seismic interpretation and gravity modelling shows the possible presence of Ligurian Tethys oceanic crust under the Gulf of Cadiz and the existence of anomalous density bodies at lower crustal levels interpreted either as pieces of exhumed sub-continental mantle or underplated material. Tapering of Iberian crust is characterized by rapid changes in the thickness of the upper and lower crust. Gravity modelling also allows the characterization of the Cenozoic contractional overprint experienced by this Mesozoic oblique margin. The presence of evaporites and the tectonic pulses that triggered their mobilization through diapirism in the Algarve Basin also controlled the paleogeographic configuration of the margin. From north to south, in the onshore, the evaporite unit, Hettangian in age and source for the salt tectonics, is observed to thicken basinward, in fault-controlled depocenters. Salt-related structures are only present in areas of thick initial evaporites. In the offshore, multiple salt-structures cored by the Lower Jurassic evaporites are documented by seismic reflection data and exploratory drilling. Offshore salt structures include the allochthonous Esperança salt nappe, which extends over an area roughly 40x60 km. The amount of saltrelated structures and their typology is observed to be controlled by the distribution of evaporite facies, which is in turn controlled by the structure of rift-related faulting. The study of salt tectonics of the Algarve Basin contributed on better constraining the paleogeography during the Hettangian and the units that were affected by diapirism. The comprehensive image of salt tectonics over the SW Iberian passive margin presented in this thesis covers all aspects from initial evaporite facies and thickness to the evolution of salt-related structures through Mesozoic extension and Cenozoic basin inversion. The SW of Iberia has undergone compression during the Late Cretaceous-Cenozoic, up to present day, due to the convergence between Africa and Eurasia. Multiple contractional features and their seismic activity have been documented immediately west of the Gulf of Cadiz, in the Atlantic domain. East of the Gulf of Cadiz, the Betic-Rif orogen and its active contractional and extensional structures are well known. Significant seismic activity reflecting a dominantly compressive stress state has been observed between these two domains. The seismic activity spans the entire Gulf of Cadiz, but the features associated with this seismicity have remained elusive. During Late Cretaceous-Cenozoic compression, basement discontinuities such as Variscan foliation and thrusts were reactivated forming south-verging monoclines. The monoclines, along with deep seawater currents, controlled the deposition of the Upper Cretaceous and Cenozoic sediments. Compression also lead to the reactivation of other basement structures (e.g., Guadalquivir Bank), which are responsible for the present-day seismicity and bathymetry in the area. The compressional phase also reactivated the salt tectonics. In conclusion, the SW Iberian margin was firstly affected by an extensional phase during the Mesozoic that resulted into a highly-extended margin the formation of oceanic crust at its deepest part. The different extensional tectonic phases that took place in the margin controlled the thickness and depositional environments of the Mesozoic sediments. Initial rifting also contributed to the evaporite basin configuration, which, together with the basement structure, triggered diapirism in the SW Iberian margin.

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18

O'Connell, Brennan. "Sedimentology and depositional history of the Miocene-Pliocene southern Bouse Formation, Arizona and California." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22300.

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The Miocene to Pliocene southern Bouse Formation preserves a record of depositional environments immediately prior to and during integration of the Colorado River to the Gulf of California. Uncertainty over Bouse paleoenvironments obscures our understanding of the timing and magnitude of regional uplift, as well as the conditions and processes that were active during integration and early evolution of the Colorado River. Prior studies over the past 20 years have concluded that the southern Bouse Formation accumulated in chain of lakes isolated from the ocean. Sedimentologic analyses presented here aid interpretation of depositional environments and provide evidence for a strong tidal influence on deposition, consistent with a marine interpretation of other prior studies. This interpretation places a critical constrain on the elevation of these deposits at ca. 5 Ma, and suggests post-Miocene uplift of the Lower Colorado River corridor. This thesis includes previously published coauthored material.

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19

Siegle, Eduardo. "Sediment transport and morphodynamics at an estuary mouth : a study using coupled remote sensing and numerical modelling." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/712.

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The balance of the physical processes that drive the morphodynamics of a complex inlet system is investigated in this work. For this purpose, an innovative technique using coupled video imaging and numerical modelling has been used to study the relative importance of the driving forces that control the sandbar dynamics at the Teignmouth inlet system. The sandbars that form the ebb tidal delta are highly dynamic, leading to a cyclic morphological behaviour. Application of the numerical model (MIKE21 HD, NSW, ST) served two separate functions. The hydrodynamic model has been used for the image processing and, combined with the sediment transport module, the full model has been used to understand the relative importance of the driving forces at the region. The iterative application of the hydrodynamic model and the video images, with the modelled water levels used as input to the image processing, provides the video-based intertidal morphology that is used in further modelling experiments. This loop is repeated several times during the three-year study period that covered a complete morphological cycle. This results in a quantitative assessment of the relative influence of the key processes that control the environment and in initial steps towards the prediction of its evolution. In order to assess the relative importance of the driving forces a series of modelling experiments were designed to include a variety of forcing conditions. These include the tidal range, wave conditions and river discharge values. The relative importance of each of the physical processes on the sediment transport and consequent morphodynamics varies across the region. The main inlet channel is dominated by tidal action that directs the sediment transport as a consequence of the varying tidal flow asymmetry, resulting in net offshore transport. Sediment transport over the shoals and secondary channels at both sides of the main channel is dominated by wave related processes, displacing sediment onshore. The interaction between waves and tide generated currents controls the transport over the submerged sandbar that defines the channel's seaward extent. High river discharge events are also proven to be important in this region as they can change sediment transport patterns across the area. Waves play a major role in the sandbar morphodynamics. Despite the relative low frequency of high wave energy events that reach the region they are responsible for large amounts of sediment displacement, catalysing some dramatic morphological changes. Therefore, the temporal distribution of storms defines the cyclic behaviour of such environments, making the system more dynamically active over the winter months. It is also during this period that river discharge values reach high peaks, increasing the capacity of the ebbing tidal flows and interacting with the opposing waves. The opposite occurs during summer periods, when less energetic conditions lead to slower morphological changes. The application of an initial sedimentation/erosion model proved to be useful in giving qualitative predictions of the morphological evolution of such a complex sandbar system, reflecting the initial morphological changes for different forcing conditions. Qualitative comparisons between the modelled sedimentation/erosion patterns and the video based observations of the changes at the dynamic offshore sandbar show that the model is able to reproduce its overall evolutionary tendency. The morphological adjustment of the system to the forcing conditions shows the progression towards the next morphological stage, allowing the initial steps towards predicting the evolution to be taken. The technique applied, coupling the numerical model with the video images, has been shown to be of great value in providing a better understanding of the processes that control the dynamics of inlet systems. At short time-scales, quantitative information about the acting processes and how they interact has been gained by the modelling experiments, and at medium time scales, the combined application resulted in qualitative predictions of the evolution of most regions of the system.

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20

Owen, Mark Anthony. "The controls on reservoir properties of Devonian sandstones in the Orcadian Basin, north east Scotland." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239529.

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21

Longley, Andrew J. "Differential compaction and its effects : the Upper Permian Capitan Reef Complex, New Mexico and West Texas." Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338248.

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22

Seger, Mark John. "The sedimentary evolution of the Gulf of Corinth Basin, central Greece." Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263294.

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23

Isles, Phillip James. "Diagenetic histories of Late Jurassic sediments in the central North sea." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308059.

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24

Siegbert, Otto. "The erosion of saltmarshes along the Severn Estuary SW Britain." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246028.

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25

Elliott, Graham. "Holocene solifluction sediments : evaluating their potential as a proxy climatic indicator." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363459.

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26

Higgs, Karen E. "A geochemical and diagenetic study of the Lower Greensand, Weald Basin." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358174.

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27

Scott, Brenda Mary. "The morphodynamics of coarse clastic beaches, examples from north Donegal, Ireland." Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242068.

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28

Pike, Jennifer. "High resolution palaeoceanography and palaeoclimatology from Late Pleistocene and Holocene laminated sediments, Gulf of California." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243123.

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29

Tomlinson, Bruce Nicholas. "Erosion studies of mixed sand beds under the combined action of waves and currents." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239502.

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30

Artzani, Nasser. "Facies and diagenesis at the Triassic-Jurassic boundary in SW Britain." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363835.

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31

Smith, Stanley Jarrell II. "Fine Sediment Dynamics in Dredge Plumes." W&M ScholarWorks, 2011. https://scholarworks.wm.edu/etd/1539616859.

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The research presented in this study is motivated by the need to improve predictions of transport and fate of cohesive sediments suspended during dredging operations. Two techniques are presented to quantify vertical sediment flux within dredge plumes. A mass-balance approach using an Acoustic Doppler Current Profiler (ADCP) is described and demonstrated to accurately estimate vertical mass flux and settling velocity for a suspension of fine sand from a dredged material placement operation. A new digital video settling column for simultaneous measurement of particle size and settling velocity is described and evaluated. The Particle Imaging Camera System (PICS) is a single-chambered, digital video settling column, which permits rapid acquisition (within 2--3 minutes) of image sequences within dredge plumes. Image analysis methods are presented, which provide improved estimates of particle size, settling velocity, and inferred particle density. A combination of Particle Tracking Velocimetry (PTV) and Particle Image Velocimetry (PIV) techniques is described, which permits general automation of image analysis collected from video settling columns. In the fixed image plane, large particle velocities are determined by PTV and small particle velocities are tracked by PIV and treated as surrogates for fluid velocities. The large-particle settling velocity (relative to the suspending fluid) is determined by the vector difference of the large and small particle settling velocities. The combined PTV/PIV image analysis approach is demonstrated for video settling column data collected within a mechanical dredge plume in Boston Harbor. The automated PTV/PIV approach significantly reduces uncertainties in measured settling velocity and inferred floc density. Size, settling velocities, and density of suspended sediments were measured with PICS within a trailing suction hopper dredge plume in San Francisco Bay. Results indicated that suspended sediments within the plume were predominantly in the clay and fine silt size classes, as aggregates with d>30 microm. Suspended bed aggregates (defined by densities of 1200 to 1800 kg m-3) represented 0.2--0.5 of total suspended mass, and size and settling velocity of this class were time invariant. Flocs (densities<1200 kg m-3) represented 0.5 to 0.8 of total suspended mass, and size and settling velocity of flocs was seen to increase with time. The peak diameter of bed aggregates and flocs occurred near 90 microm and 200 microm, respectively, corresponding to peak settling velocities of about 1 mm s-1 in each case. Floc settling velocities increased with particle size d1.1, while bed aggregate settling velocity increased like d1.3. Numerical modeling approaches to representing settling velocities for hopper dredge plumes are discussed in light of the experimental findings. Size-dependant settling velocities were well-described by a fractal-based relationship when the suspension was treated with discrete classes for each of the aggregate states. Time-dependent increases in floc size and settling velocity confirm that flocculation is a first-order process which should be included in numerical plume models. Correlations between settling velocity and suspended sediment concentration were weak and statistically insignificant, implying that commonly applied empirical relationships are inappropriate for dredge plumes.

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32

Warwick, Gail L. "The geomorphology and sedimentology of terminal fluvial systems." Thesis, University of Aberdeen, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487421.

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The geomorphology and sedimentology of terminal fluvial systems. Fluvial systems operating within drylands commonly experience downstream discharge reduction due to infiltration, evaporation and limited tributary inputs. Sediment bodies developed within the distal zones of rivers that do not drain into the sea or a lake (terminal fluvial systems) are currently represented by the terminal fan facies model. This model summarises the development of a distally thinning and fining sedimentary wedge from a coeval network of low sinuosity distributary channels as induced by the sub aerial termination ofchannelised flow under a dryland climate regime.. Extensive review of sediment fan bodies located within modern drylands highlights pronounced disequilibrium between planform character and present ephemeral flow conditions. Out of eighty documented fluvial systems no convincing examples fit the terminal fan model, including two commonly cited analogues used to support this model. In order to fully evaluate the terminal fan concept and redress the current imbalance in modern analogue studies, field work was undertaken to characterise sub aerial fluvial system termination within a single physiographic province - the Basin and Range rift complex of the southwestern U.S.A. Documentation of the potential range in fluvial style and character within this modern dryland environment is provided by the detailed study of seven terminal fluvial systems. Basin and Range terminal fluvial systems demonstrate strong geomorphic form inheritance. Fan landforms observed within medial and distal reaches of these systems predominantly represent relic Late Pleistocene highstand delta bodies into which the modern system is inset. Active terminal reaches operate within basin centre playa environments where shallo~ gradients induce frequent avulsion and the generation of composite lowstand fan bodies located downstream of lateral system confinement. These terminal features record non-coeval channel activity and the dominance of sinuous channel forms. Morphometric trends distinguish a general downstream reduction in channel scale characterised by the development of progressively narrower and shallower channel forms. Channelised flow is maintained within proximal and medial reaches but does not dominate distal reaches where sheetflow discharge is readily attained. Concomitant reductions in channel capacity and competence control the volume and calibre of fluvial material supplied to basinal environments. Progressive downstream thinning is associated with selective deposition and general basinwards sediment fining and sorting. Terminal reaches transport negligible bedload material and display a comparable depositional record to that generated by background playa sedimentation. Identified similarities with the terminal fan model include downstream loss of channel definition, sediment thinning, fining and improved sorting. Conversely, coeval distributive flow is not observed, constituent channels record moderate to high sinuosity and negligible fluvial material reaches basin centre locations. Basin and Range systems are principally responding to streampower reduction controlled primarily by gradient and enhanced by discharge attenuation. Sub aerial termination dominates due to the absence of basin centre lacustrine bodies; a condition forced by limited discharge supply from catchment reaches, compounded by transmission losses and maintained by excessive evaporation from extensive, low elevation flat playa surfaces. In conclusion, fluvial fan landforms generated exclusively from discharge attenuation do not characterise modern dryland environments. Selection of modern analogue systems for use in the interpretation and prediction of ancient fluvial successions must acknowledge the influence of high frequency and high magnitude climate fluctuations upon modern fluvial geomorphology. Key to this is an appreciation of modern processform disequilibrium and the identification of inherited planform characteristics.

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33

Murton, Julian Baird. "Thermokarst sedimentology of the Tuktoyaktuk Coastlands, Northwest Territories." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6734.

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Thermokarst sedimentology is the study of the sedimentary processes and facies associated with thermokarst. Using facies analysis, oxygen isotopes and observations of processes in the Tuktoyaktuk Coastlands, this thesis (1) classifies frozen ground according to its cryostructures and cryofacies; (2) describes thermokarst facies, facies associations and sedimentary structures; (3) examines the sedimentary processes associated with thermokarst; (4) proposes thermokarst facies models; and (5) proposes criteria for identifying thermokarst-modified sediments. The thermokarst sedimentary system of the Tuktoyaktuk Coastlands comprises uplands, slopes and basins. Beneath ice-rich uplands, downwearing thermokarst produces a thick ($\le$c. 2.5m) thaw layer in which sediments melt-out from underlying permafrost. Ice-rich slopes are subdivided into steep icy slopes and retrogressive thaw slumps, the former occurring where the percentage of excess ice in upland materials is less than c. 30-40%, the latter where it exceeds this value. As slopes retreat by backwearing thermokarst, upland materials are redeposited by alluvial and colluvial processes. Thermokarst basins form where back- and downwearing thermokarst coincide. In deep non-oriented basins containing thermokarst lakes, three stages of basin infilling are identified. The first occurs during early and rapid basin expansion, when intense backwearing thermokarst at basin margins transports large quantities of upland materials into the basins. This pulse of resedimentation initiates sublacustrine benches. The second stage beings as the rate of basin expansion diminishes, reducing the influx of clastic sediment into lakes; thus the tops of sublacustrine benches are reworked and the main depositional process changes to suspension settling in basin centres. The final stage, commencing as lakes drain, involves basin infilling by peat accumulation and by gelifluction and aeolian deposition. Two sedimentary structures relating to thermokarst are frost-fissure pseudomorphs and thermokarst involutions. Frost-fissure pseudomorphs develop through thaw-modification processes: slow subsidence, thermal erosion, refreezing, loading, buoyancy, spreading, folding, shearing and mass movement. Thermokarst involutions form primarily by water-escape or by loading and buoyancy. Involutions within a thick palaeothaw layer probably reflect the massive scale of soft-sediment deformation that accompanies regional thermokarst, and they provide a potential analogue for some Pleistocene involutions in the mid-latitudes. Five criteria identify thermokarst-modified sediments in the Tuktoyaktuk Coastlands: (1) organic-rich (and sandy) diamicton; (2) granular mud aggregates in stratified facies; (3) impure sand ($\pm$diamicton); (4) frost-fissure pseudomorphs; and (5) thermokarst involutions.

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34

Gingras, M. "Applications and approaches in ichnology, neoichnology, and sedimentology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0033/NQ46840.pdf.

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35

Van, Stempvoort Dale. "Chazy group carbonate sedimentology and diagenesis : southern Quebec." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63375.

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36

Paterson, Richard James. "Carbonate diagenesis and sedimentology in an icehouse world." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492466.

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Early diagenesis of icehouse carbonate is complex, but can significantly modify depositional porosity and permeability. During icehouse times, high-amplitude highfrequency sea-level oscillations cause subaerial exposure, with vertical migration of meteoric hydrological-zones (vadose, fireshwater and mixing-zone) through the platform sediments. Repeated cycles of subaerial exposure and associated meteoric diagnesis result in significant porosity inversion, as carbonate grains are dissolved and re-precipitated as calcite cement. This diagenetic overprinting generates a complex pattern of cementation and secondary porosity and permeability, the distribution of which cannot be predicted simple through study of diagenetic products.

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37

McInally, Alan T. "The reservoir sedimentology of ephemeral fluvial distributary systems." Thesis, Royal Holloway, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287122.

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38

Glendinning, Neil Robert William. "Sedimentology of Proterozoic, Moine rocks of west Scotland." Thesis, Royal Holloway, University of London, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246211.

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39

Hart, Stephen Francis. "Palaeoceanography and sedimentology of a mid-Cretaceous Greensand." Thesis, University of Oxford, 1991. http://ora.ox.ac.uk/objects/uuid:ac7da904-aad1-4525-8d11-9c520fc131d3.

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The Upper Albian (mid-Cretaceous) sediments of the Anglo-Paris Basin display a range of condensation phenomena, including glauconitic and phosphoritic sands, glauconitic intraformational pebble beds, and mineralised nodular hardgrounds. These are interpreted as the result of sedimentation rate fluctuations controlled by small-scale relative sea-level changes of at least regional nature. The regional signal was modified by local tectonics, including occasional synsedimentary faulting and the development of thinned successions and complex condensation horizons over broad submarine highs. Candidate sequence boundaries, marine flooding surfaces and systems tracts are proposed. Episodic, high-energy storm events record a spectrum of storm intensities and periodicities in the Upper Greensand Formation. Storm processes interacted with early submarine lithification to produce a suite of pebble-shell beds, simple and amalgamated coquinas, and storm-scoured hardgrounds. Analysis of shell bed fabrics and taphonomy indicates the important role of high-energy storms in generating a distinct event stratigraphy. Stable isotope analysis has detected a positive secular change in carbon-isotopic ratios within carbonates of dispar zone age, resolved as two smaller positive shifts across nodular hardgrounds. This correlates with the development of organic-rich sediments in a range of settings world-wide. Analytical problems, including silica diagenesis, have been addressed by a series of parallel control studies. Geochemical and petrographic analysis has confirmed the widespread development of glauconitic minerals throughout the Upper Greensand, and has been used to investigate grain evolution in a range of lithologies. A review of the global development of the Cretaceous glauconitic facies has been used to compile depositional models for a range of settings. Volumetric calculations of Cretaceous glauconite production rates have shown secular changes, with peak Aptian to Santonian values linked to transgressions across the broad shelf seas which developed globally during this time of rising sea-levels and sea-level highstand.

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Medhi, Ellora. "The sedimentology and diagenesis of deep-water carbonates." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238870.

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Pirrie, D. "Sedimentology of the Marambio Group, Larsen Basin, Antarctica." Thesis, Open University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327776.

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Moncrieff, A. C. M. "The Vendian stratigraphy and sedimentology of East Greenland." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330127.

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Sansom, Pamela Jane. "Sedimentology of the Navajo Sandstone, southern Utah, USA." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670285.

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Abbots, Frances Vivien. "Sedimentology of Jurassic syn-rift resedimented carbonate sandbodies." Thesis, University of Bristol, 1989. http://hdl.handle.net/1983/08bc3c73-7880-4cfd-afc1-0af2d9e82e18.

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This thesis discusses the sedimentology of three contrasting Jurassic carbonate sand turbidite systems from Southern Europe: the Cutri Formation (Bathonian) of Mallorca; the Vajont Limestone (Bajocian-Callovian) of northern Italy; and the Peniche sequence (Toarcian-Aalenian) of the Brenha Formation of western Portugal. These sandbodies all formed in syn-rift extensional settings which imposed a primary morpho-tectonic control on both the source platform and depositional basin morphology. The three sandbodies in question display varying geometries and architectures and are discussed in terms of the palaeogeographic, tectonic and eustatic controls that governed their individual development; as well as being used to test the recently developed apron model against that of the submarine fan. In this context oolitic carbonate aprons associated with palaeowindward and palaeoleeward platform margins have been distinguished. The Cutri Formation is interpreted as a oolitic base-of-slope apron, that displays a minor single syn-rift thinning upward megacycle (retrogradational) trend indicative of subsidence out-pacing sedimentation. The apron correlates with a eustatic sea-level drawdown and was characterised by infrequently laterally correlatable, oolitic turbidite units separated by hemipelagic interbeds. This sandbody is relatively sand-poor in nature, and is interpreted as being sourced from a palaeowindward platform margin. The Vajont Limestone is re-interpreted as an aggraded oolitic apron from its original interpretation as a sub-marine fan. The apron is composed of stacked oolitic grainstone turbidites and is locally up to 800m thick. It is interpreted as being sourced from a stable `keep up' palaeoleeward platform margin, where dominant off-bank sand transport led to development of line-sourced oolitic turbidites, which were actively aggraded by on-going basin subsidence. Statistics were used to demonstrate a random turbidite sequence which enhances the apron interpretation. The Peniche sequence is reconfirmed as a carbonate-siliciclastic fan, its facies development conforming to a siliciclastic sand-rich fan model. Statistical analysis indicates a non-random (cyclic) turbidite sequence, thereby enhancing the fan interpretation. The fan occurs as a localised development within fine-grained basinal facies and correlates stratigraphically with a eustatic sea-level drawdown. Interpreted as being sourced from a palaeoleeward margin, the sequence progradates from outer fan lobes to a thick, multi-storey braided channel complex. These syn-rift resedimented carbonate sandbodies have the potential to be stratigraphically associated with basinal source rocks and therefore may be viewed as prospective hydrocarbon reservoir facies.

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Bristow, C. S. "Sedimentology of large braided rivers ancient and modern." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380295.

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Beaumont, Hazel. "Cretaceous sedimentology of the Barmer Basin, Rajasthan, India." Thesis, Keele University, 2017. http://eprints.keele.ac.uk/3530/.

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The Barmer Basin, western India, is a well-known and prospected petroleum system. However, the Lower Cretaceous Ghaggar-Hakra Formation has not been recognised as basin fill and not documented prior to this study. The formation outcrops in rotational fault blocks at the Sarnoo Hills and surrounding areas, on the eastern Barmer Basin margin. The thesis here describes and analyses the nature and evolution of the formation at both outcrop and within the subsurface, producing facies and depositional models. At outcrop, the deposits of the Ghaggar-Hakra Formation contain three dominant fluvial sandstone successions, known as the Darjaniyon-ki Dhani, Sarnoo and Nosar sandstones. The Darjaniyon-ki Dhani Sandstone is a gravel bedload dominated, low sinuosity fluvial system, the Sarnoo Sandstone represents a mixed-load, high sinuosity fluvial system and the Nosar Sandstone is highly erosive well-developed, bedload dominated, low sinuosity fluvial system. The intervening mudrocks represent floodplain deposits. The growth and development of the fluvial system between the Darjaniyon-ki Dhani and Sarnoo sandstones indicates that the climate and tectonics were stable at the time of deposition. However, the Nosar Sandstone represents rejuvenation of the fluvial system as it is suggested that this change in deposition style is due to the activation of the fault network forming the Barmer Basin and West Indian Rift System. The facies models derived from this work are applied to the subsurface to provide interpretations of the Cretaceous succession. This provides significant insights into the sedimentology, geometries of the sediment packages with the net to gross and the petrography, all indicating the reservoir quality of the Ghaggar-Hakra subsurface material.

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Mockford, Thomas. "Sources, drivers and sedimentology of Icelandic dust events." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/33344.

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There is increasing evidence for high magnitude dust storms in high latitude environments. Yet, Aeolian processes in these areas have been largely understudied and therefore our knowledge of these systems is limited. Understanding dust emission processes from the high latitudes regions is of increasing importance because future climate scenarios indicate a reduction in terrestrial ice masses and an expansion in glacial outwash plains which are the main dust sources in high latitude environments. Of these regions, Iceland is the most researched high latitude dust source region, however our understanding of processes which lead to dust events are still poorly understood. This thesis examines the interlinking relationship between dust source and dust particle sedimentology and the physical and meteorological drivers which promote or inhibit dust emission in Iceland. This is achieved through active aeolian monitoring at source during two monitoring periods at Markarfljot, South Iceland. These measurements are complimented using secondary data sources (e.g. meteorological and satellite data), sedimentological mapping and particle analysis and laboratory abrasion experiments. This thesis is the first high resolution multi event record of dust emissions in the high latitudes and concludes by showing that potential dust concentrations and dust particle size are driven by the interlinking relationship between wind speed, sediment texture and surface moisture. Factors that affect the potential sediment availability for dust events are more important in the high latitudes than in the subtropics in driving spatial and temporal variability in dust emission. Measurements presented in this thesis are required to verify and tune regional and global modelling attempts to quantify the potential contribution of high latitude dust in the Earth system. However, further measurements are required to fully understand seasonal changes in dust emissions, across a variety of dust source units within all high latitude dust source regions.

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Junior, Paulo Ponce Arroio. "Avaliação da produção e transporte de sedimentos na bacia hidrográfica do Rio Itaqueri, municípios de Itirapina e Brotas - SP." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-02052013-083541/.

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Os processos de erosão e produção de sedimentos constituem eventos de grande relevância na atualidade, ocorrendo em escala global e ocasionando prejuízos nas esferas ambiental, econômica e social. Diversas pesquisas concentram seus esforços no sentido de entender as variáveis e os condicionantes destes fenômenos, os quais vêm sendo compreendidos por meio da multidisciplinaridade de diversas áreas do conhecimento. Nesse contexto, o presente estudo teve como objetivo realizar um diagnóstico da produção de sedimentos e de seu transporte na bacia hidrográfica do Rio Itaqueri, localizada nos municípios de Itirapina e Brotas - SP, na qual está inserido o Reservatório do Lobo ou do Broa. Dentre os elementos de análise, foi utilizado o simulador hidrossedimentológico SWAT para estimar a produção de sedimentos na bacia, bem como foi realizado o monitoramento da qualidade da água, a quantificação da carga sólida em suspensão e a determinação da granulometria do material de leito em seções de amostragem localizadas nos principais tributários do reservatório. Por meio da simulação, verificou-se que ocorrem na bacia áreas com diferentes comportamentos hidrossedimentológicos, com locais onde a produção anual média de sedimentos chega a 18 t/ha e outras áreas onde esta é próxima de zero. Foi constatado que o Rio Itaqueri contribuiu com 65% do total anual médio de sedimentos que chega ao reservatório, sendo neste rio também observados os maiores valores de carga sólida em suspensão. A parte alta da bacia configurou-se como uma área de maior aporte de sedimentos na rede de drenagem, sendo os reflexos desta dinâmica observados na qualidade da água destes locais, enquanto nas áreas de médio e baixo curso evidenciou-se a predominância de processos deposicionais. Verificou-se que as análises de parâmetros de qualidade da água e de caracterização do sedimento permitiram complementar os resultados obtidos pelo SWAT, fornecendo subsídios para uma melhor compreensão da dinâmica sedimentológica da bacia.
The soil erosion and the sediment yield are considered one of the biggest present environmental problems, a worldwide issue that inflicts environmental, economic and social damages. Many researches have efforts to understand the variables and constraints of these phenomenon, which have been understood through the multidisciplinarity of different areas of knowledge. In this context, this study attempts to obtain a diagnosis of sediment yield and its transport in Itaqueri River basin, in which is inserted the Lobo-Broa Reservoir. The hydrosedimentological model SWAT was used to estimate the sediment yield in the basin, as well was performed the monitoring of water quality, the quantifying of suspended-sediment discharge and the determination of bed material particle size distributions in streams. Through simulation, it was observed that occur in the basin different hydrosedimentological behaviors, where the average annual production of sediments is 18 t/ha, and its null in some places. It was observed that Itaqueri River contributed 65% of total average annual sediment reaching the reservoir, and this river also has the highest values of suspended-sediment discharge. The upper part of the basin was shown as an area of major input of sediment in drainage network, influencing the water quality in these sub-catchments, while middle course and low course of the river revealed the predominance of depositional processes. Water quality parameters and characterization of river bed sediment supplemented the results obtained by SWAT model, supporting a better understanding of hydrosedimentological processes.

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Estigoni, Marcus Vinícius. "Influência da quantidade e disposição de dados na modelação de terrenos aplicada a batimetria de reservatórios. Estudos de caso: UHE Três Irmãos - SP e UHE Chavantes - SP." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-29032012-111131/.

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Visando garantir a disponibilidade hídrica em seus diferentes usos são construídos reservatórios, estes sempre associados a problemas de perda de volume de armazenamento devido ao processo de assoreamento. A atualização destes dados, bem como a quantificação do assoreamento geralmente é feita através de Levantamento Batimétrico. Apesar da grande importância do tema não é observado na literatura um método padronizado para a realização de estudos batimétricos, autores e organizações apresentam métodos dispares quanto à quantidade e disposição dos dados. Deste modo, a presente pesquisa buscou elencar os métodos apresentados na literatura e analisá-los quanto a precisão obtida no cálculo de volume do reservatório, utilizando como estudo de caso o reservatório da UHE Três Irmãos (SP). Observou-se que os MDTs gerados pelos métodos não representavam com fidelidade trechos estreitos do reservatório (braços) bem como o talvegue. Foi então proposto um método para a determinação do espaçamento entre seções bem como uma rotina para geração de MDT considerando características do talvegue. O método proposto para determinação do espaçamento entre seções se mostrou capaz de representar com relativa boa precisão trechos dos braços (diferença máxima encontrada de 5,01%) e apresentou tempo de coleta de dados de 60% do método mais preciso apresentado na literatura. A rotina de geração de MDT proporcionou em média melhora de aproximadamente 30% na qualidade dos dados de volume calculados. Por meio da aplicação dos métodos desenvolvidos na UHE Chavantes foi calculado um assoreamento de 3,91%, de acordo com os resultados, sem a utilização das rotina de geração de MDT desenvolvida cálculo do volume do reservatório seria subestimado em 1,61%, superestimando o cálculo do assoreamento.
Water reservoirs are built with the main purpose of guaranteeing water supply, however, their volume always decreases due the sedimentation processes. Bathymetric surveys can be deployed to assess the current volumetric capacity of a given reservoir and to estimate and quantify the sedimentation process. Although Bathymetric surveys are considered to be a key factor when analyzing and assessing properties of a given reservoir, a standard method for its deployment is yet to be defined. Authors and research groups presents different methods about the sampling rate as well as the choice of adequate spots for data collection. The overall goal of this research was to identify and analyze the different methods deployed in previous published literature analyzing the accuracy of the volume data provided by these different methods. Três Irmãos reservoir (São Paulo) was used as a case study where methods were compared. It was pointed out that the DEMs obtained were unable to accurately represent narrower reservoirs areas (tributaries) and the thalweg. Therefore was proposed a new method for determining the distance among survey sections as well as a routine for DEM generation takes into account the thalweg characteristics. Results revealed that the data pulled out was able to represent with accuracy the tributary areas (maximum difference was 5.01%). In addition, a reduced data collection time was observed (60%) when compared against the most accurate method found in published literature. The proposed technique for DEM generation indicated approximately 30% of quality improvement in the data calculated for the reservoir volume. The developed method was applied on a bathymetric survey conducted on the Chavantes reservoir (São Paulo). The loss of reservoir capacity assessed was 3.19%. According to results, a bathymetric survey which does not deploy the new method proposed would underestimate the reservoir\'s volume by 1.61% and overestimate the sedimentation process.

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Ramos, Cléo Lindsey Machado. "A geodiversidade e a geoconservação nas Ilhas das Pombas e da Ponta Escura, Rio Grande do Sul." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/116734.

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A geodiversidade, aliada à geoconservação, é um tema relativamente novo e ainda pouco explorado pela comunidade acadêmica no Brasil. Porém, nos últimos anos percebeu-se a necessidade de estratégias de preservação da geodiversidade entendida como o meio abiótico, constituído por composições rochosas e de relevo resultantes de fenômenos geológicos e geomorfológicos que diferenciam a litologia e os minerais, gerando distintas paisagens e a grande diversidade de ambientes que propiciam o desenvolvimento das diferentes formas de vida na Terra. Com o objetivo de preservar ambientes de grande relevância ecológica como os insulares, desenvolveu-se um levantamento da geodiversidade das ilhas das Pombas e da Ponta Escura, no Parque Estadual de Itapuã, no Estado do Rio Grande do Sul, quantificando o seu valor intrínseco, seu uso potencial e a necessidade de proteção para geoconservação. Os procedimentos metodológicos compreenderam um estudo prévio da área a partir de imagens satelitais, saída a campo para coleta de amostras, análises laboratoriais, produção de material cartográfico e análise dos resultados. As ilhas apresentam gênese distinta, uma sedimentar (Ponta Escura) e outra rochosa (Pombas). As características granulométricas e morfométricas dos seus sedimentos também diferem uma da outra, onde a das Pombas apresenta maiores granulometrias variando nos tamanhos de areia muito grossa a grânulo, e grãos imaturos, enquanto na ilha da Ponta Escura observa-se maior arredondamento dos grãos e granulometria com alto percentual de areia média. Quanto à mineralogia, a ilha Ponta Escura se destaca pela alta quantidade de minerais pesados, principalmente turmalina. Os Neossolos predominam em ambas as ilhas, com subordens distintas, de Litólico e Flúvico na ilha das Pombas a Quartzarênico Órtico na Ponta Escura. A vegetação, cuja florística carece descrição científica, apresenta uma fitofisionomia caracterizada por estratos diversificados – entremeados por cactáceas de porte alto – desde um inferior herbáceo ao dossel, por vezes destacando-se árvores mais altas. A presença de indivíduos de algumas espécies exóticas da flora testemunha a interferência antrópica pretérita na cobertura vegetal original de ambas as ilhas, mais destacadamente a da Ponta Escura. Por fim, adotando-se a metodologia desenvolvida por Brilha (2005), procedeu-se com a quantificação para fins de geoconservação, onde demonstrou-se valor relativamente alto, proporcionalmente ao tamanho das ilhas e por elas pertencerem a uma área de proteção integral. Propõem-se uma ampliação da área de estudo, incluindo outras ilhas que integram o lago Guaíba, relacionando o conhecimento da geodiversidade e biodiversidade como estratégias para a geoconservação e gerenciamento da presença humana, pois a ação antrópica desregrada pode impactar diretamente ambientes que podem ser sensíveis e muito dinâmicos como nas ilhas deste estudo.
The geodiversity, combined with geoconservation, is a relatively new issue that is rarely explored by the academic community in Brazil. But in recent years, there was the need for preservation strategies of geodiversity understood as the abiotic environment, consisting of rock compositions and relief resulting from geological and geomorphological phenomena that differentiate lithology and minerals lead to the genesis of diverse landscapes and great diversity of environments that favour the development of different forms of life on Earth. In order to preserve the great ecological relevance environments like the island, a survey of the geodiversity of the Pombas and Ponta Escura islands, in southern Brazil, was developed to quantify their intrinsic value, their potential use and need for protection for geoconservation. The methodological procedures included a preliminary study of the area from satellite images, a field work for sample collecting, laboratory testing, production of cartographic material and analysis of the results. The islands have different genesis, one of them sedimentary (Ponta Escura) and the other rocky (Pombas). Particle size and morphometric characteristics of its sediments also differ one from another, where the Pombas features larger particle sizes ranging in very thick sand granule sizes, and immature grains, while on the island of Ponta Escura there was a greater rounding of grains and grain size with a high percentage of medium sand. The mineralogy, the Ponta Escura island stands out for its high amount of heavy minerals, especially tourmaline. Entisols predominate in both islands, with distinct suborders of Lithic (Leptosols/WRB-FAO) and Fluvents (Fluvisols/WRB-FAO) on the island of Pombas to Quartzipsamments (Arenosols/WRB-FAO) in Ponta Escura. The vegetation, whose floristic lacks scientific description, has a vegetation type characterized by diverse strata – interspersed with high size cacti – from a lower herbaceous to the canopy, sometimes highlighting tallest trees. The presence of individuals of some exotic species of flora witness to past anthropogenic interference with the original vegetation in both islands, most notably in Ponta Escura. Finally, adopting the methodology developed by Brilha (2005), we proceeded with the quantification to geoconservation purposes, which showed relatively high value in proportion to the islands size and to their belonging to an integral protection area. It is proposed an extension of the study area, including other islands that make up the lake Guaiba, relating the knowledge of geodiversity and biodiversity as strategies for geoconservation and management of human presence, because the unregulated human action can directly impact environments that may be sensitive and dynamic as on the islands of this study.

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Dissertations / Theses on the topic 'Sedimentology'

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