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Sedimentologia, cronologia e dinâmica progradacional das planícies costeiras de Campos Verdes e Ji (Laguna, SC); Sedimentology, chronology and progradational dynamics of the coastal plains of Campos Verdes and Ji (Laguna, state of Santa Catarina, southern Brazil)

Tanaka, Ana Paula Burgoa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 08/10/2010 PT
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Localizadas no litoral sul de Santa Catarina, as planícies costeiras holocênicas de Campos Verdes e Ji caracterizam-se por séries truncadas de cordões litorâneos alternados a campos de dunas livres. Constituem exemplo de planícies formadas em um mesmo contexto regional, porém sob condições distintas quanto ao caráter hidrodinâmico: área semiprotegida de retrobarreira (Campos Verdes) versus tômbolo de mar aberto (Ji). A meta deste trabalho é construir modelos de evolução sedimentar para estas duas planícies com base em fotointerpretação, granulometria, minerais pesados, idades LOE, cálculo de taxas de progradação e simulação computacional. A comparação visa contribuir para a compreensão dos processos formadores ou remodeladores de planícies de cordões em geral e definir o caráter, se autocíclico ou alocíclico, de cada mecanismo no caso em estudo. O desenvolvimento destas planícies teria começado durante a desaceleração da subida de NRM, pouco antes do nível máximo holocênico, alcançado por volta de 5 ka AP. A partir de padrões de transporte e retrabalhamento sedimentar deduzidos com base em estatísticas da distribuição granulométrica (tamanho médio, seleção, assimetria), combinadas com variação dos índices de minerais pesados (iINS...

A dinâmica sedimentar e a caracterização de Zonas de Erosão Acentuada (ZEA) ao longo do arco praial de Massaguaçu, SP; The sediment dynamics and the characterization of erosional Hot Spot (EHS) in Massaguaçu beach, SP

Rogacheski, Carlos Eduardo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/11/2010 PT
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Nas últimas décadas, a praia de Massaguaçu vem sofrendo processos erosivos intensos, cujos segmentos possuem taxas de recuo acentuadas, denominadas Zonas de Erosão Acentuada (ZEAs). Partindo deste problema este trabalho se propôs a entender a dinâmica sedimentar do arco praial de Massaguaçu e das possíveis causas de formação e manutenção das ZEAs. A coleta de dados se baseou no levantamento batimétrico e do clima de ondas, bem como no levantamento sonográfico de varredura lateral e na coleta de amostras de sedimento de superfície da antepraia de Massaguaçu. Para processar os dados se optou pela aplicação da modelagem numérica utilizando o modelo SWAN (propagação de ondas em águas profundas) e o modelo SMC (módulos OLUCA, COPLA e EROS, que trabalham, respectivamente, com propagação de ondas em águas rasas, simulação de correntes e simulação de transporte sedimentar). Para a formulação da discussão foram selecionados os 6 (seis) casos que apresentaram as condições de ondas mais representativas. Tais casos mostraram que a dinâmica sedimentar e os processos costeiros responsáveis pela formação e manutenção das ZEAs são controlados por dois padrões distintos de ondas incidentes. O primeiro padrão está relacionado às ondas vindas de NE - E...

Orientação da linha de costa e dinâmica dos sistemas paia e duna: Praia de Moçambique, Florianópolis, SC

Silva, Graziela Miot da
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
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Esta Tese tem como objetivo a análise da morfodinâmica da praia de Moçambique, em particular, do papel da orientação da linha de costa na influência da dinâmica dos sistemas praia-duna. A exposição da costa em relação às ondas e aos ventos exerce uma importante influência nas variações locais na altura e direção das ondas, tamanho de grão, aporte de sedimentos, transporte eólico de sedimentos, interações praia-duna e desenvolvimento da barreira costeira holocênica onde se insere a praia de Moçambique. Em uma praia de enseada com acentuada curvatura, esta influência pode ser ainda mais evidente. A praia de Moçambique, localizada na Ilha de Santa Catarina, apresenta variações ao longo de sua extensão no grau de exposição aos ventos e às ondas prevalescentes, no tipo e dimensão dos sistemas de dunas, no tipo morfodinâmico de praia, tamanho de grão e na cobertura e diversidade da vegetação. Assim, esta praia é um excelente local para a análise de qual o fator (ou combinação de fatores) é o mais importante no controle do desenvolvimento da barreira, e também para o teste de modelos existentes na literatura de interações praia-duna. O registro das ondas da região foi analisado, sendo determinado que as ondas de S-SE predominam e produzem uma deriva litorânea em direção ao norte...

Geomorphology and morphodynamics of embayed beaches in contrasting environments

Ferreira, Carlos Manuel Silva Loureiro Alves
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Tese de Doutorado
Publicado em //2012 ENG
Relevância na Pesquisa
16.8%
Tese de dout., Ciências do Mar, da Terra e do Ambiente (Geomorfologia), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2012; This study investigates the medium-term (months to years) morphodynamic variability of embayed beaches in contrasting geomorphological settings, combining two years of topographic and sedimentary monitoring in six embayments on the southwestern Portuguese coastline (three on the west coast and three on the south coast) with hydrodynamic forcing data explored using statistical and modelling techniques. From a broader, embayment-wide scale, towards a focused, process-oriented scale, the thesis addresses the following points: (i) the classification of morphodynamic state in embayed beaches, (ii) assessment of geological boundaries as constraints on the morphological variability of embayed beaches, (iii) the identification of morphodynamic mechanisms responsible for non-uniform alongshore behaviour in high-energy embayed beaches, and (iv) the development of megarips and their role in enhancing erosion during storm groups. This study demonstrates that: (i) geological control significantly influences embayed beach morphodynamic behaviour; (ii) beach morphodynamic parameters have limited ability to adequately differentiate beach types...

Vanishing Clams on an Iberian Beach: Local Consequences and Global Implications of Accelerating Loss of Shells to Tourism

Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 08/01/2014 EN
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26.5%
Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978–1981 and 2008–2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = −0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = −0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines...

Preliminary Report of Late Holocene Lake-Level Variation in Southern Lake Superior: Part 1

Johnston, John W.; Thompson, Todd A.; Baedke, Steve J.
Fonte: Indiana Geological Survey Publicador: Indiana Geological Survey
Tipo: Relatório Formato: 592204 bytes; application/pdf
EN_US
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Indiana Geological Survey Open-File Study 99-18; The internal architecture and age of development of 60 beach ridges in the Grand Traverse Bay embayment, located along the southern shore of Lake Superior on the Upper Peninsula of Michigan, were studied to generate a late Holocene relative lake-level curve for Lake Superior. Basal foreshore elevations, collected from the lakeward sides of beach ridges, were used to determine the relative elevation of Lake Superior when each beach ridge formed. The break in slope between each ridge and the lakeward swale was cored to ensure that the foreshore was penetrated and a maximum basal foreshore elevation was obtained. Basal wetland sediments, collected from swales between beach ridges, were dated to determine the age of adjacent lakeward beach ridges. Basal wetland sediments were recovered from the deepest part of selected swales along the coring transect. Basal wetland sediments provided a minimum age for the lakeward adjacent beach ridge and a least squares regression was used to reduce variability in the data and to approximate the age of unsampled wetlands. Beach ridges in the Grand Traverse Bay embayment formed between 900 and 3800 calendar years before 1950 (cal. yrs B.P.). The average timing for beach-ridge development of one ridge in the Grand Traverse Bay strandplain is 36 +/- 7.8 years. Groupings of four to six beach ridges indicate longer-term fluctuations in lake levels. Basal foreshore elevations indicate relative lake levels lowered about 4.5 m from 3800 to 1200 cal. yrs. B.P. and increased about 0.7 m from 1200 to 900 cal. yrs. B.P. A coarsening in foreshore mean grain-size per ridge also occurs at about 1200 cal. yrs. B.P. Foreshore thicknesses increase about 0.4 m from 2000 to 1200 cal. yrs. B.P. and remain fairly constant from about 1200 to 900 cal. yrs. B.P. Increased foreshore thicknesses indicate larger wave setup and may be related to a shift in the predominant wind direction that would produce greater wave setup in the Grand Traverse Bay embayment.; United States Geological Survey Global Climate Change Program Agreement No. 98HQAG2180

Preliminary Report of Late Holocene Lake-level Variation in Southeastern Lake Superior Part II: Tahquamenon Bay, Michigan

Johnston, John W.; Thompson, Todd A.; Baedke, Steve J.
Fonte: Indiana Geological Survey Publicador: Indiana Geological Survey
Tipo: Relatório Formato: 1096136 bytes; application/pdf
EN_US
Relevância na Pesquisa
27.25%
Indiana Geological Survey Open-File Study 2001-4; The internal architecture and age of development of 71 beach ridges in the Tahquamenon Bay embayment, located along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan, were studied to generate a late Holocene relative lake-level curve for Lake Superior. The record from this embayment is important because Tahquamenon Bay is located near the outlet for Lake Superior and may have experienced similar vertical movement (isostatic uplift) rates as the outlet. The lakeward side of beach ridges were cored to obtain the elevation of basal foreshore deposits, which record the elevation of the lake when each beach ridge formed. Basal wetland sediments were collected from swales between ridges and radiocarbon dated to determine the age of the next lakeward adjacent beach ridge. Regression analysis of the calibrated dates was used to approximate the age of the beach ridges. Elevation data and age data were used to construct a relative lake-level curve for Tahquamenon Bay. Beach ridges in the Tahquamenon Bay embayment formed between about 4,300 and 2,000 calendar years before 1950 (cal. yrs. B.P.). The average timing for beach-ridge development of one ridge in the Tahquamenon Bay strandplain is 31 ± 3.7 years. Groupings of four to six beach ridges indicate longer-term fluctuations in lake levels. Basal foreshore elevations indicate relative lake levels dropped rapidly (almost 5 m) from about 4...

Dune erosion, mega-cusps and rip currents modeling of field data

Keefer, Thomas B.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
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Sand dune erosion is highly episodic occurring only when storm waves coincide with high tides generating swash that impacts the toe of the dune. Owing to the episodic nature of sand dune erosion, it is difficult to observe in nature. The removal of a structure and rip-rap sea-wall from the Stilwell Hall site located in southern Monterey Bay provided a unique opportunity to study erosion processes at an accelerated rate. A 1-D wave impact line erosion model (Larson et al., 2004) was tested against data acquired at this site between April, 2004 and April 2005. The model was optimally tuned to the data by a dimensionless coefficient that relates the impact force to the rate of recession. The coefficient values ranged from 0.7-1.3x10-3, for this field data, compared with values of 1.0-2.5x10-3 previously obtained for lab and field data. Migrating rip currents create a system of mega-cusps, which are nominally 10m in width and 200m in alongshore wavelength (Thornton, 2005). The presence of megacusps is hypothesized to accelerate sand dune erosion at their embayments where the beach is steeper and narrowest (Short, 1979;Shih and Komar, 1984;Revell, et al., 2002). It was determined that the highest recession occurred at the location of the rip current/mega-cusp embayment. Changes in the surf climate are of great interest to Naval Special Warfare (NSW) and U.S. Marine Corps (USMC) forces tasked with planning and executing operations in littoral areas. Naval history is replete with operations highlighting the importance of understanding and accurate prediction of nearshore dynamics. Without the ability to predict nearshore morphologic processes...

Rip Currents, Mega-Cusps, and Eroding Dunes

Thornton, E.B.; MacMahan, J.; Sallenger, A.H.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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Submitted to Marine Geology 1 November 2006; Dune erosion is shown to occur at the embayment of beach mega-cusps O(200m alongshore) that are associated with rip currents. The beach is the narrowest at the embayment of the mega-cusps allowing the swash of large storm waves coincident with high tides to reach the toe of the dune, to undercut the dune and to cause dune erosion. Field measurements of dune, beach, and rip current morphology are acquired along an 18 km shoreline in southern Monterey Bay, California. This section of the bay consists of a sandy shoreline backed by extensive dunes, rising to heights exceeding 40 m. There is a large increase in wave height going from small wave heights in the shadow of a headland, to the center of the bay where convergence of waves owing to refraction over the Monterey Bay submarine canyon result in larger wave heights. The large alongshore gradient in wave height results in a concomitant alongshore gradient in morphodynamic scale. The strongly refracted waves and narrow bay aperture result in near normal wave incidence, resulting in well-developed, persistent rip currents along the entire shoreline.

Sedimentación intermareal en la bahía de San Sebastián, Tierra de Fuego, Argentina

Vilas, F.; Arche, A.; González Bonorino, G.; Isla, F.; Ferrero, H.
Fonte: CSIC - Instituto de Ciencias de la Tierra Jaume Almera (ICTJA) Publicador: CSIC - Instituto de Ciencias de la Tierra Jaume Almera (ICTJA)
Tipo: Artículo Formato: 692589 bytes; application/pdf
SPA
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[ES] La Bahía de San Sebastián se encuentra situada al NE de la Isla Grande de Tierra del Fuego, en la costa atlántica. Tiene forma semicircular con dimensiones de unos 55 km de N a S y de unos 40 de E a W; el rango mareal oscila entre 3,2 y 10,5 m. Existen dos áreas de sedimentación características muy diferentes: la Península del Parámo, formada por playas de gravas y la bahía, propiamente dicha, cuya zona intermareal tiene una anchura de 7 a 10 km durante la marea baja equinoccial, en la que se pueden diferenciar las siguientes áreas de sedimentación: llanuras mareales fangosas; llanura de cheniers con llanura fangosa; playa de arenagrava y llanura mareal mixta; costa acantilada sin sedimentación apreciable y complejo playa-lagoon. El viento del W, que supera los 60 km más de 200 días al año es otro factor dominante en los procesos de sedimentación del área, sobre todo en su parte más alta.; [EN] The Bay of San Sebastian is part of the NE atlantic coast of Isla Grande de Tierra del Fuego, Argentina. It is a semicircular embayment 55 km long and 40 km wide. Tidal range varies from 3,2 to 10,5 m. There are two diferent environments: The Península del Páramo, formed by gravel beaches and the Bay S.S....

Variações das propriedades granulométricas da barreira costeira da Pinheira (SC) durante a sua progradação no Holoceno Superior; Variation in the granulometric properties of the coastal barrier of Pinheira (SC) during its progradation in the Late Holocene

Amin Jr, Armand H.; Programa de Pós-Graduação em Geociências, Instituto de Geociências - UFRGS; Dillenburg, Sérgio R.; Centro de Estudos de Geologia Costeira e Oceânica, Instituto de Geociências - UFRGS
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 03/11/2010 POR
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The coastal barrier of Pinheira is located in the South-Central coast of Santa Catarina State. Its morphology and stratigraphy are typical of a regressive barrier. During the Late Holocene (last 6-5 cal ka) the barrier has prograded approximately 5,500 meters. Its progradation was determined by both a sea-level fall of 2 meters and an expressive transference of sands from the adjacent continental shelf into the beach system of the barrier. In the last 3,000 meters of progradation, corresponding to the last 3 cal ka, approximately 60 foredune ridges were formed, each ridge corresponding in average to a time interval of 50 years. The study of the granulometric properties of the modern beach-dune system, and of two old foredune ridges called intermediate and inner ridges, respectively formed at 750 and 3,000 cal years BP, has demonstrated that in the last 3 ka cal these properties have not changed significantly. This behavior is being explained by the policyclic nature of the sands consumed in the progradation, and/or by a constant or even a little change on the general dynamic conditions of the beach-dune system of the Pinheira embayment.The comparative study among the sub-environments (beach face, berm and foredune) has shown that standard deviation and skewness are potentially important sediment properties on the distinction between aeolian (foredunes) and beach (beach face) deposits.; A barreira costeira da Pinheira está localizada no litoral centro-sul do Estado de Santa Catarina. Sua morfologia e estratigrafia são típicas de uma barreira regressiva. Durante o Holoceno Superior (últimos 6-5 ka cal)...