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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Bilan des flux de métaux, carbone organique et nutriments contenus dans une rivière alpine : part des rejets urbains de l'agglomération de Grenoble et apports amont (Isère et Drac) / Balance of Metal, carbon and nutriment flux in a french alpin river : part of urban effluents of Grenoble agglomeration

Dutordoir, Solène 06 June 2014 (has links)
La prise de conscience grandissante de la contamination des cours d'eau a entraîné l'établissement de réglementations de plus en plus strictes concernant les rejets urbains et la fixation d'objectifs de qualité à atteindre pour les milieux aquatiques. Cependant, l'échantillonnage ponctuel reste une limite importante dans l'estimation des flux de contaminants, et le besoin de suivis en continu est présent dans le milieu naturel et dans les réseaux d'assainissement urbains. Cette étude porte sur la quantification de la part des rejets urbains de l'agglomération grenobloise dans les flux totaux de matières en suspension (MES), nutriments (azote, phosphore), carbone organique et éléments traces métalliques (ETM) du milieu récepteur Isère (une rivière alpine). Ce travail s'est appuyé sur un réseau de mesures en continu de débits (Q) et de MES (par turbidimétrie) à l'amont et à l'aval de l'agglomération et sur une sonde spectrométrique à l'amont, associé à des campagnes de prélèvements réguliers et renforcés pendant les épisodes de crues. Des campagnes de mesures détaillées sur les principaux sous bassins du réseau d'assainissement ont été réalisées durant la période d'étude dans le cadre du schéma directeur d'assainissement de l'agglomération grenobloise. Le croisement de ces deux approches a permis de confronter les variations spatio-temporelles des MES, nutriments, carbone organique et ETM du réseau et du milieu récepteur en 2011 et 2012. Les flux sur ces deux années ont été établis afin de déterminer la contribution des rejets urbains dans les flux du milieu récepteur. La contamination en mercure a fait l'objet d'un suivi particulier du fait de la présence d'une source significative de mercure dans la région. Enfin, une réflexion sur l'amélioration des calculs de flux par l'utilisation de relations entre les ETM/carbone organique particulaire (COP) et un paramètre mesurable en continu (MES, Q) a été menée en parallèle de l'exploitation de ces résultats. Mots-clés : Matières en suspension ; Dynamique des flux ; Nutriments ; Eléments traces métalliques ; Mercure ; Rejets urbains (par temps de pluie et temps sec), sondes de turbidité et spectrométrique. / The growing awareness of the contamination of rivers has led to the establishment of more rigorous regulations related to urban waste, and to the setting of water quality objectives to be achieved for aquatic environment. However, grab sampling remains an important limitation for the estimation of contaminant flux, and the need for constant monitoring is present in both natural environment and urban sanitation. This study focuses on the quantification of the proportion of urban waste in the Grenoble area to the total flux of 1) suspended solids (TSS), 2) nutrients (nitrogen and phosphorus), 3) organic carbon and 4) metals trace element (MTE) of the receiving environment; the Isère (an alpine river). This work was supported by a network of continuous discharge measurements (Q) and TSS (turbidimetry), both upstream and downstream of Grenoble associated with regular sampling campaigns, with a higher measurement frequency during flood events. A spectrometric probe upstream was also placed upstream. Detailed measurement campaigns on major sub-basins of the sewerage network were performed during the study period as part of the sanitation master plan of Grenoble. The combination of these two approaches allowes to relate the spatio-temporal variations of TSS, nutrients, organic carbon and MTE in the urban water network of Grenoble and in the receiving environment (the Isère) for the years 2011 and 2012. Flows of the traced parameters have been established to determine the contribution of urban waste flows in the receiving environment, over these two years. Finally, a study on how to improve the flow calculations by the use of relations between MTE / particulate organic carbon (POC ) and a continuous measurable parameter (MES, Q ) was conducted in parallel with these results. Key words: suspended solids, Nutrients, metals trace element; Mercury; urban waste; turbidimetry and spectrometric probe
452

O leitor universit?rio e a constru??o das pr?ticas de ler e escrever textos impressos e digitais

Silva, Maria da Guia 29 January 2013 (has links)
Made available in DSpace on 2014-12-17T15:06:59Z (GMT). No. of bitstreams: 1 MariaGS_DISSERT.pdf: 3445366 bytes, checksum: 68440e4fb7bb00bea09b12ac4797d669 (MD5) Previous issue date: 2013-01-29 / The construction of a mapping of the practices of reading and writing printed and digital texts, declared by graduating students from the Bachelor s degree in Science and Technology (BCT), has provided us the analysis of the course they are making in such a socio-historical moment characterized by the revolution of the post-paper. In this sense, the general objective of this research is to understand how that construction works under the point of view of those graduating students. For this, our reflection has been guided by the search of answers for some questions which have presented to us: what reading and writing conceptions BCT graduating students have; what reading and writing practices those collaborators develop; what collections they declare to have access to; what differences they declare to have between printed and digital reading and writing along the different social roles they develop; what the reader/writer identity relations of those collaborators are. To achieving the plausible answers, we have gathered a corpus composed by texts of three genres of the argument order: academic profiles (or self-portrait), opinion articles and argumentative letters. Besides, we have made semi-structured interviews and questionnaires in the online tool of the Google Docs. The methodology which supports this academic work is the qualitative research (SIGNORINI; CAVALCANTI, 1998)of ethnographic direction (THOMAS, 1993; ANDR?, 1995) in Applied Linguistics (CELANI, 2000; MOITA-LOPES, 2006) and the theoretical contribution comes from the bakhtinian perspective of language conception (BAKHTIN [1929] 1981); the socio-historical writing construction (L?VY, 1996; CHARTIER, R., 1998, 2002, 2007; COSCARELLI, 2006; CHARTIER, A., 2007; ARA?JO, 2007; COSCARELLI; RIBEIRO, 2007; XAVIER, 2009; MARCUSCHI; XAVIER, 2010); from the studies of the pedagogy of the writing (GIROUX, 1997); from the literacy studies understood as sociocultural practice, plural and situated (TFOUNI, 1988; KLEIMAN, 1995; TINOCO, 2003, 2008; OLIVEIRA; KLEIMAN, 2008), from the studies about identity in postmodernity (HALL, 2003; BAUMAN, 2005). The results of the analysis have pointed at a multiplicity of reading/writing practices of printed and digital texts developed by the BCT graduating students due to the coexistence of the modality printed and that one derived from the new mobile devices. In that multiplicity, the prevalent idea of the collaborators is that there is a continuum between printed texts and digital texts (not a dichotomy), since the option of reading/writing printed texts or digital ones is always linked to specific communication situations, which involve participants, objectives, strategies, values, (dis)advantages, besides (re)creation of discursive genres in function of the mobile devices to which those collaborators have access in the different spheres of activities that they participate. All of that has caused a deep intersection in the identity traces of college students readers/writers in the 21st century which cannot be ignored by academic formation / A constru??o de um mapeamento das pr?ticas de ler e escrever textos impressos e digitais, declaradas por graduandos do Bacharelado em Ci?ncias e Tecnologia (BCT), propiciou-nos a an?lise do percurso que eles est?o fazendo em um momento s?cio-hist?rico caracterizado pela revolu??o do p?s-papel. Nesse sentido, o objetivo geral desta pesquisa ? compreender como se d? essa constru??o sob o ponto de vista desses graduandos. Para tanto, norteou nossa reflex?o a busca por respostas a algumas quest?es que se nos apresentaram: 1) quais as concep??es de leitura e escrita dos graduandos do BCT; 2) quais as pr?ticas de leitura e escrita que esses colaboradores desenvolvem; 3) quais os acervos (digital, impresso ou ambos) a que eles declaram ter acesso; 4) que diferen?as eles declaram existir entre a leitura e a escrita impressa e a digital no exerc?cio dos diferentes pap?is sociais que desenvolvem; 5) quais as rela??es identit?rias de leitor/escrevente desses colaboradores. Para chegarmos a respostas plaus?veis, reunimos um corpus constitu?do de textos de tr?s g?neros da ordem do argumentar: perfis acad?micos (ou autorretratos), artigos de opini?o e cartas argumentativas. Al?m disso, realizamos entrevista semiestruturada e question?rio na ferramenta online do Google Docs. A metodologia que sustentou este trabalho acad?mico ? a de pesquisa qualitativa (SIGNORINI; CAVALCANTI, 1998) de vertente etnogr?fica (THOMAS, 1993; ANDR?, 1995) em Lingu?stica Aplicada (CELANI, 2000; MOITA-LOPES, 2006) e o aporte te?rico vem da concep??o de l?ngua(gem) de perspectiva bakhtiniana (BAKHTIN [1929] 1981); da constru??o s?cio-hist?rica da escrita (L?VY, 1996; CHARTIER, R., 1998, 2002, 2007; COSCARELLI, 2006; CHARTIER, A., 2007; ARA?JO, 2007; COSCARELLI; RIBEIRO, 2007; XAVIER, 2009; MARCUSCHI; XAVIER, 2010); dos estudos da pedagogia da escrita (GIROUX, 1997); dos estudos do letramento entendido como pr?tica sociocultural, plural e situada (TFOUNI, 1988; KLEIMAN, 1995; TINOCO, 2003, 2008; OLIVEIRA; KLEIMAN, 2008), dos estudos sobre identidade na p?s-modernidade (HALL, 2003; BAUMAN, 2005). Os resultados da an?lise empreendida apontam-nos para uma multiplicidade de pr?ticas de leitura/escrita de textos impressos e digitais desenvolvidas por graduandos do BCT devido ? coexist?ncia da modalidade impressa e da que decorre dos novos dispositivos m?veis. Nessa multiplicidade, a ideia que prevalece do ponto de vista desses colaboradores ? a de um continuum entre textos impressos e textos digitais (n?o uma dicotomia), uma vez que a op??o por ler/escrever textos impressos ou textos digitais est? sempre atrelada a situa??es de comunica??o espec?ficas, que envolvem participantes, objetivos, estrat?gias, valores, (des)vantagens, al?m da (re)cria??o de g?neros discursivos em fun??o dos dispositivos m?veis a que esses colaboradores t?m acesso nas diferentes esferas de atividade de que participam. Tudo isso tem ocasionado uma profunda intersec??o nos tra?os de identidade de leitores/escreventes universit?rios do s?culo XXI que n?o pode ser ignorada pela forma??o acad?mica
453

Técnicas para compreensão de rastros de execução de programas orientados a objetos

Silva, Luciana Lourdes 22 February 2011 (has links)
Several attempts to facilitate understanding the behavior of software systems have been proposed. Perfective changes in well-established software systems are easier to perform when the development team has a solid understanding of the internals. However, it is reasonable to assume that the use of an open source system to incorporate new features and obtain a new software product is an appealing approach instead of coding a new product from scratch. Considering this scenario, and considering that it is not uncommon that systems are poorly documented, there is no widely accepted approach to guide the perfective maintenance for developers with low understanding of the system or that recovers high-level information about both the structure and the behavior of large systems. This work proposes a new approach to simplify comprehension tasks of object oriented programs through the analysis of summarized execution traces. The approach is perfomed on two techniques: The rst technique enables the separation of common parts of source code from specic parts related to important features that drive the addition of the new one. An evaluation is done to verify if the summarized execution traces helps the technique to locate potential elements of code that can guide the development of a new feature. The evaluation was conducted with real-world systems and with meaningful evolution tasks. The second is based on a technique that reconstructs structural and behavioral highlevel diagrams by the analysis of summarized execution traces. Precision and recall were evaluated using two third-party open-source systems, including the webserver Tomcat. The result suggests the feasibility for using the approach on real world large scale systems. / Várias abordagens para facilitar a compreensão do comportamento de sistemas de software têm sido propostas. Mudanças perfectivas em sistemas de software bem estabelecidos são mais fáceis de executar quando a equipe de desenvolvimento tem um entendimento sólido do código fonte. Mas é razoável assumir que o uso de um sistema de código aberto para incorporar novas características e obter um novo produto de software é uma abordagem interessante, ao invés de codificar um novo produto a partir do zero. Em consideração a este cenário e considerando que não é incomum sistemas pobres em documentação, não existe uma abordagem amplamente aceita para guiar em mudanças perfectivas desenvolvedores com baixo conhecimento do sistema ou que recupera informações em alto nível de abstração sobre a estrutura e comportamento de sistemas complexos. Este trabalho propõe uma nova abordagem para simplificar tarefas de compreensão de programas orientados a objetos através da análise de rastros de execução sumarizados. A abordagem é aplicada sobre duas técnicas: a primeira permite a separação de partes comuns do código fonte das partes específicas relacionadas a características importantes que conduz a adição de uma nova. Uma avaliação é feita para verificar se os rastros de execução sumarizados ajudam a técnica na localização de elementos potenciais de código que podem guiar o desenvolvimento de uma nova característica. A avaliação foi realizada com sistemas do mundo real e com tarefas de evolução significativas. A segunda é baseada na reconstrução de diagramas estruturais e comportamentais de alto nível baseada na análise de rastros de execução sumarizados. É apresentada uma avaliação do desempenho da abordagem em termos de precisão e recall em dois sistemas públicos de terceiros, dentre eles o servidor Web Tomcat. O resultado sugere a viabilidade da abordagem para uso em sistemas reais de larga escala. / Mestre em Ciência da Computação
454

Ensino da leitura : como as letras são introduzidas no livro didático porta aberta - 1º ano

Araújo, Cristiane Menezes de 20 July 2017 (has links)
The present dissertation brings reflections on the initial teaching and learning of reading for literacy and citizenship, taking as object of investigation the textbook: Porta Aberta: letramento e alfabetização – 1º. Ano, da Ed. FTD, de Carpaneda & Bragança (2011), commonly adopted in public schools in Aracaju / SE. It aims to analyze the way how this book introduces the vowel and consonantal letters, in the light of the theoretical-methodological assumptions of the Scliar System of Literacy, considering (or not) the order of increasing complexity in the introduction of graphemes for the initial learning of the reading, such as the simplicity of the traces that make up the letters and their articulation; listening for the realization of the most perceptible phonemes by the learner, represented by the respective grapheme; the biunivocity relationship of each one of them; the graphemes that represent phonemes without variants determined by the phonetic context, among other complexities, as well as if the letters are (or aren't) presented by their names or the value that they represent. The theoretical-methodological foundations are firmly established in the works of Scliar-Cabral (2016; 2014; 2013b; 2007; 2003), whose purposes serve teaching practices aligned with the advanced discoveries of neuroscience, psycholinguistics, linguistics and the science concern to education, with emphasis on teaching strategies that highlight the importance of recognizing the graphic traits that identify the letters and the phonemic and phonological awareness in this initial phase of literacy. We know that, although the teaching of reading is compulsory in schools, the central focus for the development of this educational process is always more focused on the mechanical writing of letters, which imply the detriment of the effective learning process: there it is the causes of low reading and writing performance, according to the results presented in various National Assessments (ANA, 2015). We understand that unfortunately, even facing such a low reading performance of our children, the school still ends up silencing these questions, by not proposing an initial reading learning with more criticism, reflection and investment in the continued education of literacy teachers. It opts, then, for the reproduction of outdated approaches that, admittedly, present terrible results in national and international evaluations, starting with textbooks, sometimes they are not recommended by psycholinguistics scholars and related sciences that turn to the promising teaching of that specific ability, as evidenced in this study. The results of the work show that the methodology adopted in the textbook Porta Aberta: letramento e alfabetização – 1º. ano contrary to the advances already achieved for a scientifically based literacy by presenting the letters through nomination and according to the order of the alphabet and not according to the complexity of articulation of the traits that make them up, elencada in this study, and by introducing the vowel letters without interacting with the consonants. Finally, we believe that a process of the initial learning of reading for the exercise of citizenship passes through the automation of the recognition of: 1º - what are, how many are and how the traces that form the letters are combined; 2º what are the graphemes of written Brazilian Portuguese and the respective values (phonemes) that they represent (phonemic awareness); 3º - where the graphic accent of greater intensity goes in the stressed words and identification of the most frequent unstressed words, like articles and the coordinating conjunction "and", which allows the fast and fluent reading, to achive the textual understanding. / A presente dissertação traz reflexões sobre o ensino e a aprendizagem iniciais de leitura para o letramento e cidadania, tomando como objeto de investigação o livro didático Porta Aberta: letramento e alfabetização – 1º. Ano, da Ed. FTD, de Carpaneda & Bragança (2011), comumente adotado em escolas públicas de Aracaju/SE. Objetiva analisar o modo como o referido livro introduz as letras1 vocálicas e consonantais, à luz dos pressupostos teórico-metodológicos do Sistema Scliar de Alfabetização, atentando (ou não) à ordem de complexidade crescente na introdução de grafemas para a aprendizagem inicial da leitura, tais como a simplicidade dos traços que compõem as letras e sua articulação; a escuta da realização dos fonemas mais perceptíveis pelo aprendiz, representados pelo respectivo grafema; a relação de biunivocidade de cada um deles; os grafemas que representam fonemas sem variantes determinadas pelo contexto fonético, dentre outras complexidades, bem como se as letras são (ou não) apresentadas pelo seu nome ou pelo valor que elas representam. Os fundamentos teórico-metodológicos firmam-se nos trabalhos de Scliar-Cabral (2016; 2014; 2013b; 2007; 2003), cujos propósitos atendem a práticas de ensino alinhadas às descobertas avançadas da neurociência, da psicolinguística, da linguística e das ciências voltadas à educação, com ênfase nas estratégias de ensino que relevam a importância do reconhecimento dos traços gráficos que identificam as letras e da consciência fonêmica e fonológica nesta fase inicial da alfabetização. Sabemos que, embora o ensino da leitura seja obrigatório nas escolas, o foco central para o desenvolvimento desse processo educacional costuma estar sempre mais voltado para a escrita mecânica das letras, em detrimento do processo efetivo de aprendizagem: estão aí as causas dos baixos índices de rendimento em leitura e escrita, conforme os resultados apresentados nas diversas Avaliações Nacionais (ANA, 2015). Entendemos que, infelizmente, mesmo diante de desempenho em leitura tão baixo de nossas crianças, a escola ainda acabe silenciando essas questões, ao não propor uma aprendizagem inicial da leitura com mais criticidade, reflexão e investimento na formação continuada de alfabetizadores. Opta, então, pela reprodução de abordagens ultrapassadas que, reconhecidamente, apresentam péssimos resultados nas avaliações nacionais e internacionais, a começar, pelos livros didáticos, por vezes, não recomendados por estudiosos da psicolinguística e das ciências afins que se voltam para o ensino promissor da referida habilidade, como evidenciamos no presente estudo. Os resultados do trabalho evidenciam que a metodologia adotada no livro didático Porta Aberta: letramento e alfabetização – 1º. ano contraria os avanços já alcançados para uma alfabetização cientificamente fundamentada, por apresentar as letras mediante a nomeação e conforme a ordem do alfabeto e não conforme a complexidade de articulação dos traços que as compõem, elencada no presente estudo, e por introduzir as letras vocálicas sem interação com as consoantes. Por fim, acreditamos que um processo da aprendizagem inicial da leitura para o exercício da cidadania passa pela automatização do reconhecimento de: 1º - quais são, quantos são e como se combinam os traços que formam as letras; 2º quais são os grafemas do português brasileiro escrito e os respectivos valores (fonemas) que eles representam (consciência fonêmica); 3º - onde cai o acento de intensidade maior nos vocábulos tônicos e identificação dos vocábulos átonos mais frequentes, como artigos e a conjunção coordenativa “e”, o que permite a leitura rápida e fluente, para se chegar à compreensão textual. / São Cristóvão, SE
455

Implantação de cadeia de custódia de vestígios: implicações para a gestão da polícia civil do Distrito Federal

Cunha, Pedro Luiz Lemos 13 August 2012 (has links)
Submitted by Pedro Luiz Lemos Cunha (papitolc@hotmail.com) on 2012-09-21T03:10:27Z No. of bitstreams: 1 Dissertação - Pedro Cunha - final.pdf: 2139866 bytes, checksum: 8b06b702794a672da9aa97db9a0c1c09 (MD5) / Approved for entry into archive by ÁUREA CORRÊA DA FONSECA CORRÊA DA FONSECA (aurea.fonseca@fgv.br) on 2012-09-24T15:54:24Z (GMT) No. of bitstreams: 1 Dissertação - Pedro Cunha - final.pdf: 2139866 bytes, checksum: 8b06b702794a672da9aa97db9a0c1c09 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2012-09-27T12:10:53Z (GMT) No. of bitstreams: 1 Dissertação - Pedro Cunha - final.pdf: 2139866 bytes, checksum: 8b06b702794a672da9aa97db9a0c1c09 (MD5) / Made available in DSpace on 2012-09-27T12:11:06Z (GMT). No. of bitstreams: 1 Dissertação - Pedro Cunha - final.pdf: 2139866 bytes, checksum: 8b06b702794a672da9aa97db9a0c1c09 (MD5) Previous issue date: 2012-08-13 / O presente trabalho, de caráter exploratório e descritivo, teve por objetivo identificar requisitos, obstáculos e repercussões decorrentes da implantação de Cadeia de Custódia de Vestígios (CC) para a gestão da Polícia Civil do Distrito Federal (PCDF), que nessa unidade federativa acolhe e gerencia os institutos responsáveis pela atividade pericial oficial de natureza criminal. Primeiramente, foi realizada análise de referencial teórico visando estabelecer categorias de conteúdo. Posteriormente foram analisados normas e documentos da Secretaria Nacional de Segurança Pública e da PCDF, bem como realizadas entrevistas semiestruturadas com Dirigentes da PCDF. A técnica de tratamento de dados adotada foi a de análise de conteúdo, mediante abordagem qualitativa dos elementos de mensagem. Foram erigidas quatro categorias análise de conteúdo: elementos de identificação, legitimação e pertinência; elementos de supervisão, controle e responsabilização; elementos de gerência; e elementos operacionais, inerentes ao fomento das atividades. O resultado das análises dos documentos e das entrevistas ratificaram as categorias análise de conteúdo propostas, sendo observada maior relevância nos seguintes elementos: os procedimentos de CC são de grande relevância para a missão da Polícia Civil do Distrito Federal, proporcionam maior transparência e accountability formal e informal dos serviços prestados, e propiciam a valorização da instituição policial ante aos seus próprios servidores, estimulando-os. A Polícia Civil do Distrito Federal demonstrou precariedades materiais e procedimentais para implementação de CC, fazendo-se necessárias a aquisição e/ou edificação de instalações apropriadas, a aquisição de sistemas informatizados e de equipamentos. A aquisição de competência faz-se necessária para que os órgãos policiais possam prover o desenvolvimento e a implementação de novos procedimentos de custódias. Os procedimentos de CC demandarão mudanças de procedimentos de todos os servidores policiais que tomarem contato com vestígios materiais de crime. O convencimento do nível estratégico, o ritmo da implantação e a resistência dos policiais em adotarem novos procedimentos são os principais obstáculos para a implantação da Cadeia de Custódia de Vestígios. / The present job is an exploratory and descriptive one, aimed to identify requirements, obstacles and impacts resulting from the implementation of the Chain of Custody of Traces (CC) for the management of the Federal District Civil Police (PCDF), which receives and manages the criminal forensic activity. First, an analysis was performed to establish the theoretical content categories. Later on, were analyzed standards and documents from the National Secretariat of Public Security and PCDF, as well as realized semi-structured interviews with leaders of PCDF. The data processing technique adopted was the analysis of contents by a qualitative focus on the elements. Four categories of content analysis were raised: identification elements, legitimacy and relevance; supervision, control and accountability elements; management elements; and operational elements, inherent to the promotion activities. The results of documents and interviews analysis ratified the content analysis categories proposed, observing more relevance on the following: Chain of Custody procedures are of great relevance to the activities of the Federal District Civil Police, provides a great transparence and formal and informal accountability for services rendered, provides appreciation of the police among their own servers motivating them. The Federal District Civil Police showed procedural and material precariousness to implement the Chain of Custody, making necessary to acquire and/or build appropriate facilities, purchase computer systems and equipment. It is necessary to acquire competence for law enforcement agencies to promote the development and implementation of new procedures for custody. The procedures of the CC require changes of procedures to all police servers in contact with material traces of crime. The conviction of the strategic levels, the timing of implementation and the resistance of police enforcement in adopting new procedures are the main obstacles to implement the Chain of Custody of Traces.
456

Impact des éléments trace métalliques sur le milieu et apport de la cytométrie en flux dans l'étude du fonctionnement des lagunes de la décharge d'Etueffont (Territoire de Belfort, France) / Impact of the trace metal element on the environnment and the contribution of flow cytometry to the study of functioning of the lagoons discharge of Etuffont (Territory of Belfort, France

Al Ashoor, Ahmed Shaker 14 December 2016 (has links)
L’objectif de ce travail de thèse est d’évaluer le degré de contamination des différents compartiments du site de la décharge d’Étueffont à savoir : les lixiviats, les sédiments, l’eau souterraine, les poissons, les insectes et les microorganismes de la décharge d’Étueffont. Ce travail de recherche est structuré en neuf chapitres.Après une première partie (Part I) consacrée à une étude bibliographique, le deuxième chapitre (Part II) présente le site d’étude, c’est-à-dire l’installation de stockage de déchets non dangereux(ISDND) d’Étueffont. La troisième partie (Part III) est consacrée à l’analyse de la qualité des lixiviats dans les lagunes, les unités de stockage des déchets « Nouveau casier », « Sous casier », « Ancienne décharge », les ruisseaux du gros Pré et Mont Bonnet. La quatrième partie (Part IV) intitulée « Contamination métallique des sédiments du site de la décharge d’Étueffont », aborde l’étude de la variation spatiotemporelle des éléments traces métalliques au niveau des lixiviats et des sédiments dans les quatre lagunes du site de la décharge d’Étueffont. Afin de déterminer le degré de contamination métallique des lixiviats et des sédiments, nous avons procédé à un suivi de certains éléments localisés en amont, au milieu et en aval de chaque lagune avec un pas d’échantillonnage trimestriel entre octobre 2013 et avril 2016. La cinquième partie (Part V), complémentaire du chapitre précédent, définit plus précisément la distribution spatiale du panache à travers l’analyse de la qualité de l’eau souterraine au moyen de piézomètres. La sixième partie (Part VI) concerne les effets des métaux lourds sur les échanges gazeux et la fluorescence des chlorophylles chez (Typha latifolia). Le septième chapitre (Part VII) est consacré à l’étude des microorganismes de la décharge d’Etueffont : apport de la cytométrie en flux. Dans le huitième chapitre (Part VIII), nous aborderons l’étude de la bioaccumulation des éléments traces métalliques dans le Chironome Chironomus riparius. La dernière partie (Part IX) intitulée « Étude de la bioaccumulation des éléments traces métalliques au niveau des différents organes du gardon Rutilus rutilus», aborde l’étude de la bioaccumulation des éléments traces métalliques au niveau de différents organes (muscle, foie, arêtes et branchies). / The objective of this thesis work is to estimate the contamination level in the various compartments of the Étueffont discharge site namely: leachates, sediments, groundwater, fishes and insects. The microorganisms (< 10 µm) of the Étueffont discharge of were investigated at the single cell level by flow cytometry. This research work is structured in nine chapters.The first part (Part I), is dedicated to a literature review. Part II presents the study site, the storage of non-hazardous waste (ISDND) at Étueffont. Part III is dedicated to the analysis of leachate quality in lagoons, NC, SC, AD, MB and GP. Part IV addresses "Metal Sediment Contamination of Étueffont discharge site" It concerns the study of spatial and temporal variation of trace metals in leachate and sediment in the four lagoons landfill site of Étueffont. To determine the metal contamination level in leachate and sediment, we conducted follow-elements located upstream, middle and downstream in each lagoon with quarterly sampling between October 2013 and April 2016. Part V complements the previous chapter, by specifically defining the spatial distribution of the plume through the quality analysis of the piezometer groundwater. Part VI addresses the heavy metals impacts on gas exchange and chlorophyll fluorescence in (Typha latifolia). Part VII is dedicated to the microorganisms (<10 µm) investigation in the Étueffont discharge: by using flow cytometry. In the (Part VIII), we addressed the study of bioaccumulation of trace metallic elements (Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd and Pb) in insect Chironomus riparius. Part IX entitled "Study bioaccumulation of trace metals in the various organs of roach Rutilus rutilus" concerns bioaccumulation of trace metals in different organs (muscle, liver, bones and gills) of this fish.
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Variabilité de la zone de minimum d’oxygène du Pacifique Est équatorial au cours du Quaternaire récent / Eastern Equatorial Pacific Oxygen Minimum Zone variability over late quaternary

Cartapanis, Olivier 20 June 2012 (has links)
Cette thèse a pour objectifs de documenter les variations spatiotemporelles de la zone de minimum d’oxygène (OMZ) du Pacifique Nord-Est, et d’identifier les mécanismes qui ont causé ces variations. L’étude est fondée sur l’analyse géochimique des composants majeurs, mineurs et traces de sédiments prélevés dans le Pacifique Nord-Est, en combinant des mesures par ICP-MS et scanneur XRF. Ces mesures ont permis de distinguer l’effet de la productivité biologique de celui de la ventilation océanique sur l’oxygénation du sédiment. J’ai pu mettre en évidence le rôle prépondérant de la productivité au niveau de la Basse Californie (23°N), qui varie en phase avec les températures en Atlantique Nord durant les 120.000 dernières années. Par ailleurs, la ventilation océanique a probablement joué un rôle important au niveau du golfe de Papagayo (12°N), par l’advection de masses d’eau provenant des hautes latitudes nord et sud. L’intensité de l’OMZ du Pacifique Nord-Est serait donc influencée par des modifications des circulations océaniques et atmosphériques, liées aux climats des hautes latitudes des deux hémisphères. / This thesis aims at documenting the spatiotemporal variations of the Oxygen Minimum Zone (OMZ) of the northeastern Pacific, and identifying the mechanisms that caused theses variations. The study is based on the geochemical analyses of major, minor, and trace elements of sediments from the northeastern Pacific, by combining ICP-MS and XRF scans measurements. These measurements allowed distinguishing the effect of biologic productivity and oceanic ventilation on sediment oxygenation. I was able to highlight the predominant impact of the productivity off the Baja California Margin (23°N), which varied in phase with the high northern Atlantic temperature across the past 120,000 years. Moreover, oceanic ventilation did play an important role off the Papagayo Gulf (12°N), because of the advection of water mass coming from the high northern and southern latitudes. OMS intensity in the northeastern Pacific could thus be influenced by changes in the atmospheric and oceanic circulation, in relation to high northern and southern latitudes climates.
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Accumulation and colloidal mobilization of trace heavy metals in soil irrigated with treated wastewater / Immobilisation et transport colloidal des métaux lourds en concentrations traces dans les sols irrigués par des effluents urbains traités

Pontoni, Ludovico 15 December 2016 (has links)
La réutilisation des eaux usées traitées pour l’irrigation est globalement acceptée et pratiquée pour faire face à la pénurie d'eau et économiser les ressources de haute qualité. Bien que cette pratique présente des avantages indéniables et contribue à un usage plus durable de l'eau douce, elle n’est pas exempt de problèmes liés à l'impact potentiel sur la qualité des sols récepteurs et sur les cultures de micropolluants contenus dans l'eau réutilisée. Parmi ces polluants, les métaux lourds (ML) en concentrations traces jouent un rôle primordial en raison de leur présence systématique dans l'eau utilisée et de leur persistance une fois libéré dans l'environnement. Le devenir des ML dans les sols peut difficilement être prédit parce que les mécanismes de mobilité à travers les sols sont extrêmement variés et liés à des phénomènes simultanés et très complexes impliquant différents équilibres chimiques. Les ML, comme beaucoup d'autres contaminants, ne sont pas seulement partagé entre la phase immobile (le sol) et les phases mobiles présentes dans l'eau. En effet, les colloïdes et les nanoparticules agissent comme une troisième phase mobile, avec leurs propres propriétés rhéologiques et des vitesses de migrations qui leur sont propres. Ce dernier aspect a été l'un des principaux objectifs d’étude de la thèse. Plusieurs essais expérimentaux ont été menés en irriguant un sol standard selon l'Organisation de coopération et de développement économiques (OCDE) avec une eau usés traités réel et / ou synthétiques, contenant des ML en concentrations traces. Pour chaque test, un sol spécifique (avec différentes teneurs en matière organique) et des eaux usées traitées de composition différente (avec différentes concentrations en métaux traces, de salinité, de la teneur en matière organique pour les eaux usées synthétiques, ou des eaux usées traitées réelles) ont été choisi afin d'évaluer les effets des conditions différentes sur le devenir global des ML. L'augmentation de la matière organique du sol de 2,5 à 10% a linéairement amélioré la mobilité des Cd, Cu et Ni avec une augmentation de la mobilité maximum de 35,6, 43,7 et 49,19% pour le Cd, Cu et Ni, respectivement. Pour la plupart des expériences, les ML ont été capturés dans la couche superficielle du sol (0,5 à 1 cm). Néanmoins, des pics de contamination ont été détectés à des profondeurs différentes dans les couches plus profondes du sol. L’étude de la composition des lixiviats montre des variations de concentrations fonction du métal étudié et des caractéristiques du sol et des eaux usées. Des pics de métaux dans le lixiviat sont apparus en même temps que la libération de la matière et / ou la libération de silicates organiques, ce qui démontre l'implication significative des colloïdes dans le transport des métaux. La concentration en sodium (20 mM) a été démontrée un impact fort sur la réduction de la mobilisation colloïdale et que plus de 95% du métal apporté a été détecté dans la couche superficielle du sol en dépit de sa teneur en matière organique. La salinité affiche donc des effets significatifs. L'irrigation avec des eaux usées traitées présentant une très haute teneur en Ca et Mg (111 et 134 mg / L, respectivement) a abouti à la libération moyenne plus élevée de silicium à partir de la matrice inorganique du sol (8,2 mg / L) par rapport à la faible salinité des eaux usées artificielle (1,9 mg / L). Par conséquent, la mobilisation ultérieure de Cd, Cu, Ni et Zn a été observée lorsque le sol a été irrigué avec des eaux usées traitées réelles. Une caractérisation spectroscopique avancée des lixiviats a été réalisée pour identifier les agrégats colloïdaux libérés par le sol dans le but d’en déterminer leur nature, leurs propriétés chimiques et leur état d'agrégation / Reuse of treated wastewater for agricultural purposes is worldwide accepted and practiced to face water scarcity and save high quality resources. Although such practice has undoubtable advantages and is certainly more sustainable respect to the use of fresh water, it is not exempt from severe concerns related to the potential impact on the receiving soil and on the crops of potentially harmful pollutants contained in the reused water at trace levels. Among these pollutants, trace heavy metals (HMs) play a primary role due to their spread presence in the used water and to their persistence once released in the environment. The fate of HMs in the soils can be hardly predicted as mechanisms of mobility through soils are extremely diverse and related to highly complex simultaneous phenomena and chemical equilibria. HMs, in fact, as many other contaminants, are not only partitioned between the solid immobile and the water mobile phases. Indeed, colloids and nanoparticles act as a third mobile phase, with their own rheological properties and velocity. This latter aspect has been one of the main focus of the thesis. In details the thesis describes the results of several experiments conducted irrigating the OECD standard soil with real and/or synthetic wastewater, containing HMs in trace. For each test a specific soil (e.g. varying the organic matter content) and wastewater composition (e.g. varying the metals concentration, the salinity, the organic matter content, or testing real treated wastewaters) has been chosen in order to evaluate the effects of different conditions on the overall HMs fate. The increase of soil organic matter from 2,5 to 10% linearly enhanced the mobility of Cd, Cu and Ni up to a maximum mobility increase of 35.6, 43.7 and 49.19 % for Cd, Cu and Ni, respectively. In most experiments metals accumulated in the top soil layer (0.5 - 1 cm). Nevertheless peaks of contamination were detected at different depths in the soil deeper layers and at different leaching time in the leachates depending on the metal and on the soil and wastewater characteristics. Peaks of metals in the leachate appeared simultaneously with release of organic matter and/or release of silicates, demonstrating outstanding involvement of colloids in metals transport. Sodium concentration (20mM) decidedly reduced colloidal mobilization whereas more than 95 % of the influent metal was detected in the top layer despite the soil organic matter content. Salinity displayed different effects. The irrigation with real treated wastewater with quite high content of Ca and Mg (111 and 134 mg/L, respectively) resulted in higher average release of silicon from the soil inorganic matrix (8.2 mg/L) compared to the low salinity artificial wastewater (1.9 mg/L). Consequently higher mobilization of Cd, Cu, Ni and Zn was observed when the soil was irrigated with real treated wastewater. An advanced spectroscopical characterization of the leachates was performed to identify such colloidal aggregates. The observation of 3D excitation-emission matrix demonstrated in all the leachates samples the presence of fulvic (230-450 nm ex-em fluorescence area) and humic (330-445 nm ex-em) substances. In this context, a novel analytical method was developed to quantify phenolic substances in soil matrices allowing the monitoring of humic matter migration in soil profiles. The novel method was more accurate and more precise respect to the traditional one, allowing to obtain higher recovery of total phenols in peat soil (15.5 % increase) with a decrease of the coefficient of variation (30.1% decrease). Organic water soluble colloids were extracted from the peat used to prepare the OECD standard soil and characterized. Results of size exclusion chromatography highlighted the supramolecular structure of the extracted organic matter. Such structure was further confirmed through fluorescence and 1H-NMR spectroscopy
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Seabirds as bioindicators of Southern Ocean ecosystems : concentrations of inorganic and organic contaminants, ecological explanation and critical evaluation / Les oiseaux marins bioindicateurs des écosystèmes austraux : niveaux de contaminants métalliques et organiques, explication écologique et évaluation critique

Carravieri, Alice 20 October 2014 (has links)
L’océan Austral est soumis à la redistribution globale des contaminants par les voies atmosphérique et océanique. Cependant, la contamination des écosystèmes austraux est très peu connue, en particulier dans le secteur Indien. De par leur toxicité, leur mobilité et leur capacité à se bioaccumuler dans les tissus des organismes et à se bioamplifier dans les réseaux trophiques, le mercure (Hg) et les polluants organiques persistants (POPs) comptent parmi les contaminants les plus préoccupants. Du fait de leur position élevée dans les réseaux trophiques, les oiseaux marins sont exposés à de grande quantités de contaminants par la voie alimentaire. En conséquence, ils sont souvent utilisés comme bioindicateurs de l’état de contamination des écosystèmes, par le biais des plumes et du sang, qui peuvent être échantillonnés de façon non destructive. Ma thèse s’est intéressée aux nombreuses espèces d’oiseaux marins (plus de 40) qui nichent au sein des Terres Australes et Antarctiques Françaises, au sud de l’Océan Indien, afin de décrire et expliquer les niveaux de contaminants le long d’un large gradient latitudinal, de l’Antarctique à la Zone Subtropicale, et d’identifier les meilleures espèces bioindicatrices pour un suivi à long terme de la contamination de ces écosystèmes. Au cours d’une première étape méthodologique, les manchots et les poussins de toutes les espèces ont été identifiés comme de bons bioindicateurs de contamination puisque, à la différence de la plupart des oiseaux adultes, ils présentent une faible variabilité des niveaux de contaminants dans les plumes. Au cours d’une seconde étape explicative, l’effet de facteurs intrinsèques (traits individuels) et extrinsèques (écologie alimentaire déduite grâce à la méthode des isotopes stables) sur les niveaux de contaminants a été évalué dans les plumes des oiseaux de la communauté de Kerguelen (27 espèces) et dans le sang du grand albatros de Crozet (180 individus dont les traits de vie sont connus). L’écologie alimentaire s’est avérée être le principal facteur explicatif des niveaux de contaminants, tandis que l’âge, le sexe, la phylogénie et le statut reproducteur jouent un rôle mineur. La classe d’âge est néanmoins un facteur à prendre en compte, puisque les poussins montrent souvent des concentrations inférieures aux adultes. Au cours d’une troisième étape, les variations spatio-temporelles de la contamination ont été étudiées en utilisant une sélection d’espèces bioindicatrices et en tenant compte de leur écologie alimentaire. Plusieurs résultats portant sur différentes espèces (oiseaux océaniques) et populations (poussins de skua) ont montré que, contrairement aux prédictions, l’exposition des oiseaux au Hg augmente graduellement des eaux antarctiques aux eaux subantarctiques puis aux subtropicales, alors que l’exposition aux POPs, en accord avec la théorie de la distillation globale, montre la tendance inverse. D’autre part, la comparaison des concentrations en Hg dans les plumes de manchot, effectuée entre des spécimens de musée et des échantillons actuels, indique que leur exposition au Hg n’a pas changée depuis les années 1950-1970. Toutefois, des espèces subantarctiques montrent une tendance à la hausse. De futures études devraient viser à l’utilisation des plumes comme tissu de référence pour l’évaluation et le suivi de la contamination des écosystèmes, en particulier en ce qui concerne les POPs. Parmi les nombreuses espèces étudiées au cours de ces travaux de thèse, les bioindicateurs les plus pertinents se révèlent être le manchot empereur et le pétrel des neiges (Antarctique), le manchot royal, le pétrel bleu et l’albatros à sourcil noirs (subantarctique), le gorfou sauteur subtropical et l’albatros à bec jaune (subtropical). Le suivi à long terme de ces espèces permettra d’évaluer l’évolution temporelle de l’état de contamination de l’océan Austral. / Antarctic and subantarctic marine environments are reached by inorganic and organic contaminants through ocean circulation and atmospheric transport. Yet, environmental contamination is poorly known in the Southern Ocean, in particular in the Indian sector. Among environmental contaminants, mercury (Hg) and persistent organic pollutants (POPs) are primarily of concern, because they are toxic, highly mobile, and they bioaccumulate in the tissues of living organisms and biomagnify up the food web. Seabirds, as upper predators, are exposed to large quantities of contaminants via food intake and have widely served as biomonitors of marine contamination, notably through the non-destructive sampling of their feathers and blood. My doctoral work has focussed on the abundant and diverse seabird species (more than 40) breeding in the French Southern and Antarctic Lands, southern Indian Ocean, in order to describe and explain contaminant concentrations over a large latitudinal gradient, from Antarctica to the subtropics, and to identify the best bioindicator species for contaminant biomonitoring. In a first methodological step, seabirds with synchronous moult of body feathers (adult penguins and chicks of all species) were recognised as good candidates as bioindicators, because, unlike most adult birds, they present low within-individual variation in feather contaminant concentrations. In a second explanatory step, the influence of intrinsic (individual traits) and extrinsic factors (feeding ecology inferred from the stable isotope method) driving variation in contaminant concentrations was evaluated in feathers of the large avian community of the Kerguelen Islands (27 species) and in blood of wandering albatrosses from the Crozet Islands (180 birds of known individual traits). Feeding ecology was the main factor driving variation in contaminant concentrations of blood and feathers, both at the community, population and individual levels, whereas age, sex, phylogeny and breeding status played a minor role. Age-class was however an important intrinsic factor to consider, with chicks usually having lower concentrations than adults. In a third step, spatio-temporal patterns of contamination were studied through selected bioindicator species and by taking into account their feeding habits. Results from different species (oceanic seabirds) and populations (skua chicks) showed that, contrary to predictions, Hg exposure gradually increases from Antarctic to subantarctic and subtropical waters, whereas, in accordance with the global distillation theory, POPs exposure has the opposite pattern. Comparisons between penguin feathers from museum collections and contemporary samples showed that bird exposure to Hg is overall not different today when compared to 50-70 years ago, but subantarctic species are possibly experiencing an increasing trend. Future research efforts should be focussed on the use of feathers as biomonitoring tools, in particular for POPs determination. The best recommended bioindicator species include the emperor penguin and snow petrel (Antarctic), king penguin, blue petrel and black-browed albatross (subantarctic), and northern rockhopper penguin and Indian yellow-nosed albatross (subtropical). Future biomonitoring studies on these species will give invaluable insights into the poorly-known temporal trends of environmental contamination in the Southern Ocean.
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Sedimentological and ichnological characteristics of Dur At Tallah siliciclastic rock sequence, and their significance in the depositional environment interpretation of tidal-fluvial system (Upper Eocene, Sirt Basin, Libya) / Caractéristiques sédimentologiques et ichnologiques de la séquence silicoclastique du Dur At Talah : importance dans l'interprétation des séries tidales et fluviatiles (Eocène supérieur, le bassin de Syrte, Libye)

Abouessa, Ashour 19 December 2013 (has links)
La séquence sédimentaire du Dur At-Talah, située dans la partie sud du bassin de Syrte au centre de la Libye, est composée de 150 m d'épaisseur de roches principalement siliciclastiques (grès, siltites et argiles). L'importance de cette séquence est liée en partie à l'importance du bassin de Sirt qui est un des plus grands réservoirs d'hydrocarbures de Libye. La séquence est également un des plus important site de fossiles de vertébrés de l’Eocène supérieur, l'âge de la séquence. Les études antérieures, bien que très limitées par rapport à l'importance de cette zone, se sont concentrées principalement sur le contenu paléontologique de la séquence. L’étude sédimentologique n’avait été jusqu’à ce jour que très peu abordée. Cette thèse est un travail basé sur l’examen des affleurements et où l'accent est mis sur les structures sédimentaires et biogéniques (traces fossiles), visant à définir et à interpréter les faciès sédimentaires qui ont construit la séquence du Dur At Talah. L’ étude de la séquence a conduit à diviser la totalité de l’affleurement en trois intervalles génétiquement liés. Le plus ancien que nous avons appelé la « New Idam Unit » (environ 80 m d’épaisseur), est composé de grès très fins, de siltites et d’argiles. Cette unité (New Idam Unit) est recouverte en discordance par la « Sarir Unit » (environ 50 m d’épaisseur), composée de grès fins à moyens à faisceaux de litages entrecroisées dans sa partie inférieure (environ 25-30 m d’épaisseur) et de grès grossiers à microconglomératiques dans sa partie supérieure (environ 20-30 m d’épaisseur). La « Sarir Unit » est ainsi divisée en « Sarir inférieur » et « Sarir supérieur ». La « New Idam Unit » présente des dépôts qui sont attribués à un milieu main estuarien. La série débute par des dépôts d’environ 35 m d’épaisseur typiques d’un estuaire externe. Les 45 mètres qui lui font suite passent progressivement à des dépôts tidaux caractéristiques d’un estuaire interne. La Surface d'inondation maximale se situe entre les deux intervalles. Au-dessus de cette surface les indicateurs fluviaux augmentent et les indicateurs de marées diminuent progressivement, offrant ainsi un indice pour la migration de la rive de rivage vers le bassin (vers le Nord). La sous-unité du Sarir inférieur qui avait été interprétée avant ce travail comme dépôts fluviatiles, préserve pourtant des structures sédimentaires multi-échelles qui sont le résultat incontestable de processus de marée. Ceci est particulièrement évident dans la partie inférieure de l’unité « Sarir inférieur » (la Lower Lower Sarir Unit ; LLS). Dans la partie supérieure de l’unité Sarir inférieur (Upper Lower Sarir; ULS), les indicateurs de dynamique fluviale dominent largement sur ceux de la marée. Le Sarir inférieur est donc interprété comme un système deltaique mis en place lors d’une régression normale. Cette fois-ci, la surface maximale d'inondation se situe entre le LLS et ULS. Le « Upper Lower Sarir » (ULS) se terminée par une discordance subaérienne, avec de nombreuses traces d’émersion conservées au sommet de l'ULS. Celles-ci sont recoupées par le « Upper Sarir » qui montre des marqueurs fiables d'environnement de dépôt strictement fluvials. Les dépôts du « Upper Sarir » enregistre la séquence de bas niveau marin. Cette étude fournit des informations précieuses concernant le dépôt des séquences dans le bassin de Syrte au cours de la fin de l'Éocène. Elle fournit également une étude originale sur la dynamique tidale dans des milieux marins margino-littoraux. / Dur At Talah sedimentary sequence, located at the southern side of the Sirt Basin in central Libya, is composed of 150 m thick of mainly siliciclastic rocks. The importance of this sequence is linked to the importance of the Sirt Basin as one of large hydrocarbon reservoirs in Libya. The sequence is also an excellent site for vertebrate fossils of Late Eocene, the age of the sequence. Previous studies, though very limited compared to the importance of this area, are focused on its paleontological content. Sedimentology received only scant attention before this project. This thesis is an outcrop based study in which the focus is given to the sedimentary and biogenic (trace fossils) structures, aiming at defining and interpreting depositional facies which building up the sequence. The study is mainly based on field data which are analyzed on the light of related published literature and on the comparison with modern sedimentary environments. Results of facies analysis have led to splitting the entire sequence into three genetically related intervals. The oldest, we called the New Idam Unit (around 80m), is composed of very fine sandstones to mudstones. New Idam Unit is unconformably overlain by the Sarir Unit (around 50m), composed of medium grained cross bedded sandstones (the lower 25-30 m) changes up to very coarse and microconglomeratic sandstone (the upper 20-30 m). Thus, the Sarir Unit is split into the lower Sarir Subunit and upper Sarir subunit. The New Idam Unit presents both classical and unusual sedimentary and biogenic indicators that attribute this unit to estuarine depositional environment. It starts with outer estuarine (the lower 35 m) and ends up with inner estuarine (the upper 45 m). Maximum flooding surface is located in between. Above this surface the fluvial indicators increase and tidal indicators decrease, thus providing clue for basinward (North) migration of the shoreline. The lower Sarir subunit which was previously interpreted as fluvial deposits, preserves multi-scale sedimentary structures that undoubtedly belong to tidal processes. This is especially evidenced at the lower part of the lower Sarir Subunit (LLS). Fluvial indications over dominates the tidal ones in the upper part of the lower Sarir (ULS). Due to this configuration the whole lower Sarir subunit is interpreted as shallow marine, deltaic, depositional system, occurred during sea level ¨normal¨ regression. This time, maximum flooding surface is located between the LLS and ULS. The lower Sarir subunit is terminated by subaerial unconformity, with evidences of subaerial exposure preserved at the top of the ULS. These are intruded by the upper Sarir subunit which presents clear evidences of strictly fluvial environment of deposition. The deposits of the upper Sarir subunit record the low stand system tract part of the Dur At Talah sequence. In addition to the outlined results, the sequential pattern of the depositional events is suggested for the entire sequence of Dur At Talah. This study provides a valuable information regarding the depositional and sequential aspects of the Sirt Basin during the late Eocene, it also provide an unique case study for the better understanding of the shallow marine tidal deposits.

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