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Cronologia e sedimentologia dos depósitos eólicos quaternários da costa catarinense entre Ouvidor e FlorianópolisMendes, Vinicius Ribau 04 May 2012 (has links)
Dentro da região litorânea central do Estado de Santa Catarina, compreendida entre as praias do Ouvidor e dos Ingleses, foram delimitadase estudadas cinco áreas que abrigam tanto campos de dunas ativos quanto estabilizados. Com base em dados meteorológicos obtidos de 1962 a 2010, como registros diários de precipitação e deintensidade e rumo de vento, inferiu-se que a tendência de estabilização recente, observada nos campos de dunas atuais por comparação de fotografias aéreas de diferentes datas, resulta da combinação de aumento da precipitação com redução da intensidade do vento. Este dois fatores inibem o transporte eólico de sedimentos para o campo de dunas, seja pelo efeito de aumento de coesão da areia exercido pela umidade seja pelo favorecimento da colonização vegetal nas zonas de deflação. Persistentes nas últimas três décadas, estes fatores têm reduzido gradualmente as áreas deareia expostas ao retrabalhamento eólico, o que diminui cada vez mais a deriva eólica efetiva, culminando na fixação dos campos de dunas. Os depósitos sedimentares de dunas e paleodunas eólicas foram agrupados, por critérios morfológicos, estratigráficos, granulométricos e mineralógicos, em quatro gerações (G1 a G4), correlatas às reconhecidas previamente na literatura. A geração mais antiga (G1) possui, todavia, distribuição de idades mais ampla do que se pensava, podendo portanto, por critérios geocronológicos, vir a ser subdividida. Os resultados sedimentológicos apontam para tendências de engrossamento, melhora de seleção granulométrica e assimetria mais positiva, da geração mais antiga para a mais nova, o que é atribuído a influência de sucessiva reciclagem de sedimentos entre as gerações, sem descartar o efeito, em paralelo, de mudanças de energia e/ou morfodinâmica costeira. As idades obtidas para as gerações antigas pelo método da luminescência opticamente estimulada (LOE) permitem observar certa coincidência com contextos de linha de costa estável e de clima em transição de menos úmido para mais úmido. A relação observada entre as idades LOE obtidas e as curvas de variação do nível relativo do mar (NRM) e de paleopluviosidade, associadas ao modelo de estabilização de dunas recentes por aumento de umidade e queda de energia eólica, permite sugerir que a iniciação dos campos de dunas costeiros da região, em suas diferentes gerações, seja favorecida por situações de NRM estável e/ou em inversão de tendência, e por clima menos úmido e mais ventoso. A estabilização dos campos de dunas, em contrapartida, seria favorecida pela subida de NRM, pelo aumento da chuva e pela diminuição da intensidade dos ventos. Do ponto de vista do controle climático, a condição de iniciação de campos de dunas mencionadacoincidiria com momentos de enfraquecimento do Sistema de Monções da América doSul (SMAS), correlatos a períodos mais quentes no hemisfério norte. E a condição favorávelà estabilização de campos de dunas ocorreria nos momentos de intensificação do SMAS, correlatos a períodos mais frios no hemisfério norte. / This master dissertation refers to five areas withactive and stabilized eolian dune fields in the central coast of the Santa Catarina State, southernBrazil. In this region, a recent tendency to stabilization of active dune fields is inferred from the comparison between aerial photographs of different years. Meteorological data obtained between 1962 and 2010, including daily records of rainfall, wind intensity and wind direction, indicate increasing precipitation and weakening wind to this period. The combination of these two factors inhibits the eolian sediment transport to the dune field, as effect of increasing sand cohesion by wetting and vegetal colonization in deflation zones. Being persistent in the last three decades, these factorshave reduced gradually the sand areas exposed to eolian reworking and decreased more and more the effective eolian drift, culminating in the stabilization of dune fields. The sedimentary deposits of eolian dunes and paleodunes were grouped, by morphological, stratigraphic, granulometric and mineralogical criteria in four generations (G1 to G4), analogous to that previously recognized in the literature. The older generation (G1) has a wider age distribution than previously thought and can be subdivided regarding the geochronological aspect. The grain-size analysis data indicate trends of sediment coarsening, better sorting and more positive skewness, from the older to the younger generation,what is attributed to the influence of successive reworking of sediments between generations, withoutdiscarding the effect of changes in the transport energy and/or beach morphodynamics. The ages of the three older generations obtained by optically stimulated luminescence (OSL) method show coincidence with contexts of stable coastline and with climate in transition from less to more wet. The observed relationship between the OSL ages andthe relative sea level (RSL) and paleoprecipitation curves, besides the model of recent dune stabilization by the wet increasing and wind energy decreasing, allow us to suggest that the initiation of the dune fields in their different generations, in this coastal region, can be favoredby moments of stable and / or in reversal trend RSL, as well by less humid and more windy weather. In other hand, the stabilization of the dune fields would be favored by higher RSL, increasing rain and decreasing wind intensity. From the perspective of climate control, the mentioned condition to initiation of dune fields agree with moments of weakening of the South America Summer Monsoon System (SASM), related to warmer periods in the northern hemisphere. Analogously, the favorablecondition for the stabilization of dune fields would coincide with moments of intensification of the SASM, related to colder periods in the northern hemisphere.
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INSTABILITES DES INTERFACES ECOULEMENT / FOND ERODABLE : APPROCHES ASYMPTOTIQUESKouakou, Jacques Kouamé Kan 27 September 2005 (has links) (PDF)
Les dunes de sable dans le désert ou les rides sur les plage sont issues de problématiques d'interaction entre un écoulement (d'eau et/ou de vent) et un tas de sable. Sous l'hypothèse que les perturbations dues à l'hydrodynamique de l'interaction restent confinées dans une fine couche visqueuse près du fond de l'écoulement, nous obtenons des résultats analytiques et numériques de la stabilité des rides sur un fond érodable à long terme. Ces résultats sont comparés favorablement à certaines études expérimentales. Dans le cas d'un tas de sable posé sur un fond non érodable, nous montrons qu'avec la seule longueur de saturation ou le seuil de mise en mouvement des grains, il est possible de relier des configurations finales de dunes de tailles différentes, sous des cisaillements différents, à partir de transformations auto-similaires.
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A legislative and biophysical assessment of the regulation of off-road vehicles on South African beaches.Davey, Jennifer. January 2003 (has links)
The legislative management of Off-Road Vehicles (ORVs) on beaches has evolved over a
period of time in response to a range of influences and changing circumstances within the
various social, institutional, economic and biophysical systems.
The impact of ORVs on beaches in South Africa is multifaceted and when viewed holistically
incorporates the interaction between the biophysical, social, economic and institutional
environments. This Study focuses only on the legislative and biophysical environments
associated with the impact of ORVs on beaches.
Sustainable coastal development draws attention to the "process" character of sustainable
development that needs to be worked towards over time in an iterative manner. It highlights
the need to take into account the current reality of prevailing circumstances, the uncertainty of
the future, limited understanding of coastal ecosystems and communities, and the complex
interactions between and within the human and non human components of the environment.
An understanding of the ecological integrity and effective governance dimensions (being the
focus of Study), although only two of the five dimensions of sustainable coastal development,
contributes towards an understanding of the sustainability of the impact of ORVs on beaches
within the South African context.
The legislative environment is investigated from the management perspective of the national
Department of Environmental Affairs and Tourism. This Study determines whether effective
governance is being achieved through the ongoing management of the impact of ORVs on
South African beaches. The institutional management at a national level has resulted in the
conditional banning of ORVs from beaches, which has resulted in promoting the ecological
integrity of beaches, therefore contributing towards sustainable coastal development.
The physical system is investigated where appropriate in terms of the biophysical parameters
within which ORVs are managed on beaches within the inter-tidal zone as per the ORV
General Policy (1994). In order to understand the biophysical system within which ORVs are
managed, the existing literature and research concerning the impact of ORVs on beaches is
reviewed, including existing literature on beach geomorphology and beach biota. A Case Study Area was selected for an experimental investigation to determine the biophysical impact of
ORVs on sandy beaches. The experiment was conducted at Leven Point, north of Cape Vidal
situated on the KwaZulu-Natal north coast within the St Lucia Marine Reserve.
The ORV General Policy (1994) has been superseded by the ORV Regulations (2001), which
do not however, specify the biophysical delineation of the management of ORVs on beaches.
This Study has included recommendations applicable to the management of ORVs on beaches
in South Africa in terms of the ORV Regulations (2001). These recommendations advocate
the conservation of the dynamic biophysical environment of the inter-tidal zone on beaches,
and the need to take a sustainable coastal development approach to applications for
Recreational Use Areas (RUAs) in terms of the ORV Regulations (dated 21 December 2001). / Thesis (M.Sc.)-University of Natal, Durban, 2003.
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The final final final cut : Fan edits och hur de samverkar med filmindustrinPontén, Joon January 2011 (has links)
Begreppet ”fan edits” betecknar filmer som klipps om av fans, vilka är missnöjda med hur en adaption för vita duken som gjorts. I min uppsats vill jag påvisa dels hur samspelet mellan fans och filmmakare/filmbolag sett och ser ut, dels försöka klargöra varför copyright/fair use är så knepigt att applicera på området.
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Beach-dune morphodynamics and climate variability impacts of Wickaninnish Beach, Pacific Rim National Park Reserve, British Columbia, CanadaBeaugrand, Hawley Elizabeth Ruth 07 September 2010 (has links)
To date, there has been little research on the morphodynamics of Canada’s Pacific mesotidal beach-dune systems and their potential response to climate variability and change. Accordingly, this study examines and characterizes the morphodynamics of a mesotidal beach-dune system on western Vancouver Island (Wickaninnish Beach) and investigates its potential response to extreme seasonal storms, climate variability events, and climate change trends. This research also informs protected areas management approaches, whose effectiveness is
important to the conservation of early successional and proportionately rare specialized dune species. Research methods include repeat cross-sectional surveys, repeat vantage photographs, and analysis of the wind, wave, and water level regime. Both the regional wind regime and aeolian sediment transport regime are bimodal, with
a WNW (summer) component and a SE (winter) component. The nearshore littoral sediment
transport regime is characterized by both longshore and rip cell circulation cells. To date, survey results are informative only of seasonal changes. Longer-term monitoring will better reveal contemporary trends of the beach-dune system. A high dune rebuilding potential (aeolian sand
transport potential = 9980 m3 m‐1 a‐1, resultant aeolian sand transport = 3270 m3 m‐1 a‐1 at 356 degrees) was found based on the incident wind regime and sand grain diameter. A threshold elevation for dune erosion was defined at 5.5 m aCD. Erosive water levels were analyzed using three approaches yielding the following results. Erosive water levels are reached on average, ~3.5 times per year; with a probability of 65% in any given year; and, annual return levels are 5.59 m aCD, suggesting erosive water levels are reached annually. Statistical relations show that the positive phase of El Niño Southern Oscillation (ENSO) (El Niño) shares the most variance with the incident oceanographic regime (e.g., significant wave height, peak period), and although a causal relationship cannot be drawn, El Niño may contribute to the occurrence of erosive events on Wickaninnish Beach. Beyond El Niño, overall findings suggest climate variability signals are manifest in regional erosional water level
regimes.
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Effects of topography on the spatial variation of landcover diversity and distribution in a prairie sandhill ecosystemHamilton, Tayler Kaylen January 2013 (has links)
This thesis investigates whether topography has a quantifiable effect on the spatial
distribution of landcover within an inland sand dune ecosystem. To accomplish this, an
investigation was undertaken to compare the associations between various topographic
characteristics and landcover distribution within the Great Sand Hills (GSH), Saskatchewan.
The methodology comprised a spatial analysis of digital topographic and landcover data. In
terms of landcover diversity, results shows that there is a moderate association between
topography and landcover diversity in the GSH, and that results vary with spatial scale.
Similarly, results show modest predictability for one particular community type (trees)
thought to be strongly related to topographic position in this region. Several environmental
factors are proposed that might overprint the topography-landcover association. Overall,
this thesis expands the geographic context of the link between topography and landcover,
while also demonstrating the utility of high resolution topographic and landcover data and
the importance of spatial scale. / x, 90 leaves : col. ill. ; 29 cm
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Die herwinning van waaisand op Walker Bay-Staatsbos, Hermanus langs die Suidwes-Kaapse kus deur van Ammophila arenaria (L) link gebruik te maakReyneke, P. G. 12 1900 (has links)
Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 1985. / Die ontstaan van waaisand langs die Suidwes-Kaapse kus en die geskiedenis van waaisandherwinning in die gebied word behandel. Die gebruik van Ammophila arenaria (marram) en A. breviligulata tydens die herwinning van waaisand in ander lande word bespreek.
Verskillende metodes kan gebruik word om die resultate van die onderskeie behandelings op die groei van marramgras te bepaal.
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La paroisse de Soulac de la fin du XVIe au milieu du XIXe siècle : les transformations d’un territoire littoral entre la Gironde et l’Atlantique / The Soulac parish from the end of the 16th century to the middle of the 19th century : the transformations of coastal land between Gironde and AtlanticCaillosse, Pierre 21 October 2015 (has links)
Située à la pointe du Médoc, la paroisse de Soulac (communes actuelles de Soulac-sur-Mer et du Verdon-sur-Mer, Gironde) est selon une expression médiévale « à la fin des terres ». Prise en tenaille entre l’Atlantique, à l’ouest, et la Gironde, à l’est, son finage comprend un long liseré littoral (14 km de rivages océaniques et 11 km de rives estuariennes) qui l’expose aux phénomènes d’origine naturelle liés à des dynamiques maritimes et fluviomaritimes. Depuis la fin du XVIe siècle, le sable accumulé le long du littoral sous la forme de dunes est porté par le vent sur les habitations et les cultures, poussant à l’abandon de l’église de Soulac et du bourg primitif au milieu du XVIIIe siècle. Parallèlement, le littoral est fortement attaqué par l’érosion qui se généralise au milieu du Siècle des Lumières. À l’est, les marais salants s’envasent, réduisant en moins d’un siècle la moitié de leur surface. Enfin, les zones basses de la paroisse sont exposées aux submersions marines, qui demeurent cependant peu fréquentes. Ce micro-espace de 50 km² constitue un bon point d’observation pour étudier les transformations d’un territoire littoral et l’adaptation des populations à ces changements. Prenant appui sur des ressources documentaires importantes (archives textuelles et cartographiques) et continues dans le temps (de la fin du XVIe au milieu du XIXe siècle), l’analyse croise les méthodes historiques traditionnelles avec les possibilités offertes par les outils informatiques contemporains tels que les SIG (géolocalisation et extraction de données qualitatives et quantitatives de cartes anciennes). L’analyse spatio-temporelle permet la reconstitution géohistorique des paysages de Soulac sur un temps long, en mettant en avant les dynamiques naturelles, les transformations importantes et les réponses apportées par les habitants. Ces derniers, d’abord impuissants et livrés à eux-mêmes par les autorités, tentent de s’adapter aux changements en adoptant plusieurs stratégies au cours du XVIIIe siècle. De la simple retenue des sables par des palissades à l’assèchement des marais doux et salés, ils essayent de répondre aux contraintes exercées sur eux par leur environnement. Mais ce sont les actions de l’État au début du XIXe siècle qui conditionnent la réussite des opérations de lutte et le début d’une nouvelle ère. Les dunes fixées par des pins et l’érosion enrayée par la construction d’ouvrages donnent naissance au paysage actuel de la pointe du Médoc. Plus qu’une simple monographie paroissiale, cette étude de cas permet de s’interroger sur notre environnement et les interactions que son exploitation et son peuplement influencent. Reconstruire sur un temps long les transformations permet une meilleure compréhension des risques et des phases de construction d’un espace géographique, et offre un recul historique permettant de mieux comprendre les événements récents. / Situated at the pointe du Medoc region, the parish of Soulac (modern day communes of Soulac-sur-Mer and Verdon-sur-Mer) is according to a medieval expression “at the end of the lands”. Squeezed between the Atlantic to the west, and the Gironde estuary to the east, the area includes a long coastline (14km of ocean coastline and 11km of estuary banks) which exposes it to phenomenon of natural origin linked to these maritime and fluvial-maritime movements. Since the end of the sixteenth century, the sand accumulated along the length of the coastline in the forms of dunes and carried by the wind onto habitations and cultures, causing the abandonment of the Soulac church and the early initial village in the mid eighteenth century. Simultaneously, the coastline was strongly attacked by erosion that spread in the middle of the Age of Enlightenment. To the east, the flat salt marshes were getting wider, reducing half their surface in less than a century. Finally, the low-lying areas of the parish are exposed to marine submersions, despite beginning with little frequency. This micro space, of 50km2, encompasses a good observation point in order to study the transformations of coastal land and the adaptations of populations to these changes. Taking support from important documentary resources (textual archives and cartographic maps) and continuous in the time (from the end of the 16th century to the middle of the 19th century), the analysis combines traditional historic methods with the possibilities offered by the contemporary computer tools, such as GIS (geolocation, extraction of qualitative data and quantitative old maps). The spatiotemporal analysis allows for the geohistoric reconstruction of the Soulac landscape over a long period, reflecting the natural dynamics, the important transformations and the responses from the inhabitants. The inhabitants, firstly made powerless by the authorities and had given up on themselves, have adapted to the changes by adopting many strategies throughout the course of the 18th century. From the simple control of the sand, using boundaries that dry up the soft, dirty marshes, they are trying to respond to the constraints forced upon them by their environment. However, the actions of the government at the beginning of the nineteenth century which allow for the success of the preventative actions and the start of a new era. The dunes fixed by pine trees and the erosion, stopped by the construction of structures, has given birth to the current landscape at the point of Medoc. More than a simple parish monograph, this case study allows us to ask questions about our environment and the affect that the interactions of cultivation and people have. Reconstructing over a long period of time the transformations offers a better understanding of the risks and the phases of construction of a geographical area offering a historical reviews which allows for a better understanding recent events.
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[en] COASTAL DYNAMICS OF THE COAST OF TUTÓIA (MA) LITTORAL, FROM THE SATELLITE IMAGES MULTITEMPORAL ANALYSIS AND THE USE OF GEOPROCESSING / [pt] DINÂMICA COSTEIRA DO LITORAL DE TUTÓIA (MA), A PARTIR DA ANÁLISE MULTITEMPORAL DE IMAGENS DE SATÉLITE E DO USO DE GEOPROCESSAMENTOPOLYANA SÁ MENEZES DA SILVA 18 January 2019 (has links)
[pt] A paisagem costeira presente no Litoral Oriental do Maranhão tem como um de seus elementos campos de dunas móveis, compondo um ambiente dinâmico que expressa alterações significativas tanto espaciais quanto temporais. Como parte dessa paisagem, o litoral de Tutóia apresenta feições eólicas relativamente próximas à linha de costa resultantes da ação conjugada de ondas, correntes costeiras, ação fluvial, variações do nível do mar e fatores climáticos que contribuíram para a configuração da atual paisagem costeira ao longo do tempo. Por estar inserida na Área de Proteção Ambiental do Delta do Parnaíba, a área de estudo merece destaque por sua importância socioeconômica e ambiental, o que justifica o desenvolvimento de estudos que contribuam para um melhor entendimento dos processos e da dinâmica que atuam na região. O presente trabalho tem como principal objetivo identificar alterações que ocorreram na paisagem costeira do município de Tutóia (MA), associadas aos processos de erosão e progradação da linha de costa e a dinâmica de evolução do campo de dunas ao longo dos últimos 23 anos. Espera-se com isso contribuir para o melhor conhecimento da dinâmica do Litoral Oriental maranhense fornecendo informações que sirvam de subsidio para futuros projetos de preservação e ordenamento do uso e ocupação da zona costeira. Para o desenvolvimento da pesquisa foram analisadas imagens de satélite (1994 a 2017) e elaborado uma série temporal por meio de técnicas de geoprocessamento, como sensoriamento remoto e sistemas de informações geográficas (SIG). Os resultados implicam em um mapa da evolução multitemporal dos campos de dunas móveis, onde houve um aumento na velocidade de deslocamento das dunas e na erosão da linha de costa, o que possibilitou identificar a significativa influência da Zona de Convergência Intertropical (ZCIT), que quando submetida à anomalia Temperatura da Superfície do Mar (TMS) e ocorrência do El Niño, interfere na região Nordeste do Brasil, aumentando o período de escassez de chuvas e a intensidade dos ventos alísios, sendo estas as causas do aumento da velocidade de migrações de dunas nos períodos analisados. A presente dissertação reuniu importantes informações a respeito da dinâmica costeira local, principalmente em um trecho do litoral com escassez de informação, mas, é importante dar continuidade aos estudos desenvolvidos na área, aprofundando o conhecimento acerca do comportamento desses ambientes tendo em vista o planejamento das ações relacionadas aos processos de ocupação e exploração dos recursos naturais e que se almeje o desenvolvimento equilibrado, respeitando as intensa variabilidade do ambiente costeiro. / [en] The coastal landscape present in the Eastern Coast of Maranhão has dune fields as one of its elements, composing a dynamic environment that expresses significant spatial and temporal changes. As part of this landscape, the littoral of Tutóia exhibits eolian features relatively near to the coastline resulting from the combined action of waves, coastal currents, fluvial action, sea level variations and climatic factors that contributed to the current coastal landscape configuration over time. Being inserted in the Environmental Protection Area of Parnaíba Delta, the study area deserves attention because of its socioeconomic and environmental importance, which justifies the development of studies that contribute to a better understanding of the processes and dynamics that operate in the region. The present work main objective is to identify changes that occurred in the coastal landscape of Tutóia (MA) city, associated with the coastline erosion and progradation processes and the dune fields evolution dynamics over the last 23 years. It is expected to contribute to a better knowledge of the Eastern Coast of Maranhão dynamics by providing information that will serve as a subsidy for future preservation and planning the use and occupation projetcs of the coastal zone. For the research development, satellite images (1994 to 2017) were analyzed and a time series was elaborated through geoprocessing techniques such as remote sensing and geographic information systems (GIS). The results imply a multitemporal evolution map of the mobile dune fields, where had an increase on the dune displacement velocity and on the coastal line erosion, which allowed identifying the significant influence of the Intertropical Convergence Zone (ITCZ), which when subdued to the Sea Surface Temperature (SST) anomaly and the El Niño occurrence, interferes in Brazil northeast region, increasing the rain scarcity period and the trade winds intensity, being these the causes of the dune migration velocity increase in the analyzed period. The present dissertation gathered important information about the local coastal dynamics, especially in a stretch of the coast with scarce information, however, it is important to continue the studies developed in the area, deepening the knowledge about the behavior of these environments owing to the planning of actions related to the occupation and exploitation of natural resources processes and that a balanced development is craved, respecting the intense variability of the coastal environment.
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Cronologia e sedimentologia dos depósitos eólicos quaternários da costa catarinense entre Ouvidor e FlorianópolisVinicius Ribau Mendes 04 May 2012 (has links)
Dentro da região litorânea central do Estado de Santa Catarina, compreendida entre as praias do Ouvidor e dos Ingleses, foram delimitadase estudadas cinco áreas que abrigam tanto campos de dunas ativos quanto estabilizados. Com base em dados meteorológicos obtidos de 1962 a 2010, como registros diários de precipitação e deintensidade e rumo de vento, inferiu-se que a tendência de estabilização recente, observada nos campos de dunas atuais por comparação de fotografias aéreas de diferentes datas, resulta da combinação de aumento da precipitação com redução da intensidade do vento. Este dois fatores inibem o transporte eólico de sedimentos para o campo de dunas, seja pelo efeito de aumento de coesão da areia exercido pela umidade seja pelo favorecimento da colonização vegetal nas zonas de deflação. Persistentes nas últimas três décadas, estes fatores têm reduzido gradualmente as áreas deareia expostas ao retrabalhamento eólico, o que diminui cada vez mais a deriva eólica efetiva, culminando na fixação dos campos de dunas. Os depósitos sedimentares de dunas e paleodunas eólicas foram agrupados, por critérios morfológicos, estratigráficos, granulométricos e mineralógicos, em quatro gerações (G1 a G4), correlatas às reconhecidas previamente na literatura. A geração mais antiga (G1) possui, todavia, distribuição de idades mais ampla do que se pensava, podendo portanto, por critérios geocronológicos, vir a ser subdividida. Os resultados sedimentológicos apontam para tendências de engrossamento, melhora de seleção granulométrica e assimetria mais positiva, da geração mais antiga para a mais nova, o que é atribuído a influência de sucessiva reciclagem de sedimentos entre as gerações, sem descartar o efeito, em paralelo, de mudanças de energia e/ou morfodinâmica costeira. As idades obtidas para as gerações antigas pelo método da luminescência opticamente estimulada (LOE) permitem observar certa coincidência com contextos de linha de costa estável e de clima em transição de menos úmido para mais úmido. A relação observada entre as idades LOE obtidas e as curvas de variação do nível relativo do mar (NRM) e de paleopluviosidade, associadas ao modelo de estabilização de dunas recentes por aumento de umidade e queda de energia eólica, permite sugerir que a iniciação dos campos de dunas costeiros da região, em suas diferentes gerações, seja favorecida por situações de NRM estável e/ou em inversão de tendência, e por clima menos úmido e mais ventoso. A estabilização dos campos de dunas, em contrapartida, seria favorecida pela subida de NRM, pelo aumento da chuva e pela diminuição da intensidade dos ventos. Do ponto de vista do controle climático, a condição de iniciação de campos de dunas mencionadacoincidiria com momentos de enfraquecimento do Sistema de Monções da América doSul (SMAS), correlatos a períodos mais quentes no hemisfério norte. E a condição favorávelà estabilização de campos de dunas ocorreria nos momentos de intensificação do SMAS, correlatos a períodos mais frios no hemisfério norte. / This master dissertation refers to five areas withactive and stabilized eolian dune fields in the central coast of the Santa Catarina State, southernBrazil. In this region, a recent tendency to stabilization of active dune fields is inferred from the comparison between aerial photographs of different years. Meteorological data obtained between 1962 and 2010, including daily records of rainfall, wind intensity and wind direction, indicate increasing precipitation and weakening wind to this period. The combination of these two factors inhibits the eolian sediment transport to the dune field, as effect of increasing sand cohesion by wetting and vegetal colonization in deflation zones. Being persistent in the last three decades, these factorshave reduced gradually the sand areas exposed to eolian reworking and decreased more and more the effective eolian drift, culminating in the stabilization of dune fields. The sedimentary deposits of eolian dunes and paleodunes were grouped, by morphological, stratigraphic, granulometric and mineralogical criteria in four generations (G1 to G4), analogous to that previously recognized in the literature. The older generation (G1) has a wider age distribution than previously thought and can be subdivided regarding the geochronological aspect. The grain-size analysis data indicate trends of sediment coarsening, better sorting and more positive skewness, from the older to the younger generation,what is attributed to the influence of successive reworking of sediments between generations, withoutdiscarding the effect of changes in the transport energy and/or beach morphodynamics. The ages of the three older generations obtained by optically stimulated luminescence (OSL) method show coincidence with contexts of stable coastline and with climate in transition from less to more wet. The observed relationship between the OSL ages andthe relative sea level (RSL) and paleoprecipitation curves, besides the model of recent dune stabilization by the wet increasing and wind energy decreasing, allow us to suggest that the initiation of the dune fields in their different generations, in this coastal region, can be favoredby moments of stable and / or in reversal trend RSL, as well by less humid and more windy weather. In other hand, the stabilization of the dune fields would be favored by higher RSL, increasing rain and decreasing wind intensity. From the perspective of climate control, the mentioned condition to initiation of dune fields agree with moments of weakening of the South America Summer Monsoon System (SASM), related to warmer periods in the northern hemisphere. Analogously, the favorablecondition for the stabilization of dune fields would coincide with moments of intensification of the SASM, related to colder periods in the northern hemisphere.
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