As pesquisas em ecologia isotópica aplicadas à arqueologia têm se desenvolvido amplamente nas últimas duas décadas em todo o mundo, porém poucos trabalhos direcionados unicamente para essa área foram produzidos no país. Este trabalho tem por objetivo gerar dados para testar dois modelos contrastantes sobre as estratégias de subsistência empregadas por sociedades pré-históricas do Brasil Central, desde o final do Período Pleistoceno (ca. 12.000 anos A.P.) até o final do Holoceno utilizando isótopos estáveis como ferramenta de análise. Para tal foram utilizadas amostras de material ósseo arqueológico humano e faunístico provenientes de duas regiões do Brasil Central: Lagoa Santa e Vale do Peruaçu, Minas Gerais. Deste material foram extraídas amostras de colágeno que foram analisadas em um espectrômetro de massa a fim de obter valores de 13C e 15N. Os resultados obtidos para as populações humanas apontam para uma dieta onívora em ambas, com uma forte tendência ao consumo de recursos vegetais em comparação com as demais espécies analisadas da cadeia trófica. Os indivíduos mais jovens de Lagoa Santa (até 5 anos de idade) apresentaram uma diferença estatística significativa nos valores de 15N quando comparados aos demais indivíduos da mesma região, demonstrando assim uma tendência na população a um prolongamento da amamentação. Foram encontradas também evidências de uma possível alteração climática no Vale do Peruaçu a partir da variação de 15N em Kerodon rupestris no decorrer do Holoceno. O sítio de Santana do Riacho, na região de Lagoa Santa apresentou prováveis indícios da presença de milho com dois indivíduos de Cavia aperea que sinalizaram uma dieta tipicamente consumidora de plantas C4 (média 13C= -12,19 e 15N= 2,63) estatisticamente distinta dos demais indivíduos da amostra, entretanto como o espaço amostral é reduzido mais analises são necessárias para confirmar essa tendência. / Research in the field of isotopic ecology applied to archaeology has been in constant development for the past two decades, however only a few studies had been made towards this area in Brazil. This study has the objective of generating data to test two contrasting models regarding the strategies of subsistence used by pre-historical societies of Central Brazil, since the end of the Pleistocene (ca. 12.000 years B.P.) and during the Holocene using stable isotopes as an analytic tool. For such, there had been used faunistic and human archaeological bone samples, from two different regions of Central Brazil: Lagoa Santa and Vale do Peruaçu, Minas Gerais state. From this material collagen samples were extracted and, afterwards, analyzed in a mass spectrometer in order to obtain the 13C and 15N values. The results obtained for both human populations indicate a typically omnivorous diet, with a strong tendency towards vegetable consumption if compared with the other animals used in the trophic web characterization. The young human individuals from Lagoa Santa (up to 5 years old) show a statistically different 15N values if compared to the rest of the human remains from the same population, showing a tendency for extensive breastfeeding age. It was also found evidence of a possible climatic change at Vale do Peruaçu around Middle Holocene demonstrated by 15N variations in Kerodon rupestris. Santana do Riacho site, in the Lagoa Santa region showed probable indications of maize presence, as two Cavia aperea samples yielded typical C4 plant consumption (average 13C= -12.19 and 15N= 2.63) also proving to be statistically different from the other individuals of the same species in the whole sample, on the other hand as the sample size is too small and more analysis are needed in order to confirm this tendency.

O Paleolago Cemitério, formado sobre um domo magmático carbonatítico do Cretáceo Superior, em Catalão, GO, compreende um depósito lacustre espesso, datado entre 51.780 ± 400 14C anos AP e 27.500 ± 4.000 anos AP, e rico em fósseis, particularmente de esponjas de água doce. A presença inédita de camadas de espongilitos e diatomitos no mesmo depósito, bem como de estruturas inteiramente preservadas, gêmulas e porções do esqueleto das esponjas, permitiu a proposição da presente tese, que teve como objetivo identificar as condições ambientais que poderiam ter favorecido essa singular produção e preservação de esponjas. Por conseguinte, investigou-se também a atual Lagoa Serra Negra, em Patrocínio, MG, formada sobre um domo carbonatítico similar àquele do paleolago e sujeita ao regime climático do Bioma Cerrado. As gêmulas e fibras do retículo esqueletal das esponjas integralmente preservadas nos sedimentos do Paleolago Cemitério, bem como fragmentos de espongilito e diatomito, foram fixadas em suportes e analisadas ao MEV. A análise taxonômica das espículas nos sedimentos amostrados em todas as fácies do paleolago, bem como nas 10 amostras de sedimentos da Lagoa Serra Negra, foi feita sobre lâminas permanentes obtidas após preparações laboratoriais destinadas à avaliação ao microscópio óptico. Análises sedimentológicas (granulometria e matéria orgânica) também foram realizadas em amostras de todos os sedimentos recuperados do paleolago e em duas amostras de sedimentos da Lagoa Serra Negra. A água da lagoa foi analisada para as principais características físicas e químicas. A análise taxonômica das espículas nos sedimentos da Lagoa Serra Negra indicou a contribuição das mesmas cinco espécies de esponjas que formaram largos depósitos em áreas vizinhas incluindo os do Paleolago Cemitério, Dosilia pydanieli Volkmer-Ribeiro (1992), Metania spinata (Carter, 1881), Trochospongilla variabilis Bonetto & Ezcurra de Drago (1973), Radiospongilla amazonensis Volkmer-Ribeiro & Maciel (1983) e Heterorotula fistula Volkmer-Ribeiro & Motta (1995). As análises dos sedimentos da lagoa também revelaram um depósito biosilicoso conspícuo, com destaque para as espículas de esponjas, o que permitiu uma comparação com o depósito do Paleolago Cemitério. A integração de todos os resultados permitiu propor uma interpretação para a evolução do Paleolago Cemitério. Assim, cinco fases de mudanças ambientais foram identificadas no depósito do paleolago, que correspondem à instalação (fase lótica e erosiva), ao estabelecimento e desenvolvimento do lago, e à colmatação do lago, essa última correlacionada ao Último Máximo Glacial (UMG). Com base nos requisitos ecológicos das espécies de esponjas identificadas no depósito foi, além disso, possível inferir os padrões climáticos relacionados com as respectivas fases do paleolago. A presença inédita da espécie de esponjas Corvoheteromeyenia australis no Paleolago Cemitério, atualmente registrada apenas no sul da América do Sul, indicou que incursões polares originárias da Antártida foram frequentes durante o último período glacial, e podem ter desempenhado um papel notável no Brasil central. No entanto, por um curto período de tempo, condições climáticas mais secas e quentes podem ter predominado, como sugerido pela presença de Corvomeyenia thumi. Não resta dúvida que o paleoclima favoreceu o processo cárstico no domo de Catalão I que levou à formação da bacia do paleolago, onde as condições ambientais favoreceram à existência de uma particular comunidade de esponjas, hoje típicas de lagoas do Bioma Cerrado. Profundidade, fluxo e residência de água na bacia, bem como disponibilidade de substrato e concentração de sílica, essa última favorecida pelas rochas-fonte circundantes, foram condições ambientais chave para a formação dos depósitos biosilicosos no Paleolago Cemitério. / The Cemitério Palaeolake, formed in a Late Cretaceous magmatic carbonatitic dome in Catalão, GO, comprises a thick lacustrine deposit, dated between 51,780 ± 400 14C years BP and 27,500 ± 4,000 years BP, and rich in fossils, particulary freshwater sponges. The unprecedented presence of spongillite and diatomite layers in the same deposit, as well as the entire structures of gemmules and skeleton strutures of the sponges, allowed the proposition of the present thesis, which aimed to identify the environmental conditions that could have favored this singular production and preservation of sponges. Accordingly, the actual Serra Negra Lake, in Patrocínio, MG, was also investigated once it was formed on a carbonatite dome, similar and close to that of the Paleolake and subjected to the climate regime of the Cerrado biome. The fully preserved gemmules and fibres of the skeletal reticulum of sponges from the Cemitério Paleolake sediments, as well as the fragments of its spongillites and diatomites, were fixed on stubbs and analysed using SEM. The taxonomic analysis of spicules in the sediments sampled from all the facies of the paleolake as well as in 10 sediment samples from the Serra Negra Lake was conducted on permanent slides obtained after laboratorial preparations designed for evaluation under optical microscope. Sedimentological analyses (granulometry and organic matter) were also performed using all the sediment samples recovered from the paleolake and two sediment samples obtained from the Serra Negra Lake. The lake water was analysed for the main physical and chemical characteristics. The taxonomic analysis of spicules in the sediments of the Serra Negra Lake indicated the contribution of the same five sponge species, which formed large deposits in the neighbouring areas including those of the Cemitério Paleolake, Dosilia pydanieli Volkmer-Ribeiro (1992), Metania spinata (Carter, 1881), Trochospongilla variabilis Bonetto & Ezcurra de Drago (1973), Radiospongilla amazonensis Volkmer-Ribeiro & Maciel (1983) and Heterorotula fistula Volkmer-Ribeiro & Motta (1995). The analyses of current sediments of the lake also revealed a conspicuous biosilicious deposit, highlighting the sponge spicules, which allowed a comparison with the Cemitério Paleolake deposit. All these results led us to propose an interpretation of the evolution of the Cemitério Paleolake. Therefore, five phases of environmental changes were identified in the paleolake deposit, corresponding to the installation (lotic and erosion phase), establishment and development of the lake, and colmatation of the lake, with the latter correlating to the Last Glacial Maximum (LGM). Moreover, on the basis of the ecological requirements of the sponge species identified in the deposit, it was possible to infer the probable weather patterns related to the respective phases of the lake. The unprecedented presence of the sponge species Corvoheteromeyenia australis in the Cemitério Paleolake, which is presently recorded only in southern South America, indicated that polar incursions originating from the Antarctic were frequent during the last glacial period and may have played a notable role in what is now the central Brazil. However, for a short time, drier and hotter weather conditions may have predominated, as suggested by the presence of Corvomeyenia thumi. There is no doubt that the paleoclim favored the karstic process in the dome of Catalão I, which led to the formation of the paleolake basin, where environmental condictions favored the existence of a particular sponges community, currently typical of the lakes of the Cerrado Biome. Depth, flow and water residence in the basin as well as the availability of substrate and silica concentrations, with the latter favored by the surrounding source rocks, were the key environmental conditions for the formation of biosiliceous deposit in the Cemitério Paleolake.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-06-27T15:43:37Z No. of bitstreams: 1 DISSERTAÇÃO MESTRADO RENATA LIMA DA COSTA.pdf: 3354797 bytes, checksum: 32c50ae4ec262f98d3a557ed8afe9eaa (MD5) / Made available in DSpace on 2017-06-27T15:43:37Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO MESTRADO RENATA LIMA DA COSTA.pdf: 3354797 bytes, checksum: 32c50ae4ec262f98d3a557ed8afe9eaa (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / nstitut de Recherche pour le Développement / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / Sabendo-se que as condições hidrológicas de um sistema flu vial depende diretamente do clima regional, e que as mudanças climáticas do Holoceno atingiram várias regiões da Amazônia de diferentes formas, este trabalho visa r econstituir, através de estudos de sondagem lacustre, o cenário paleoambiental e as condi ções hidrológicas atuantes durante o Holoceno no lago Acarabixi, localizado na p lanície sedimentar do médio Rio Negro. A caracterização das unidades litológicas foi real izada através de medidas de densidade, teor em água, matéria orgânica, granulomet ria, e lâminas de material sedimentar bruto . A origem da matéria orgânica foi avaliada a partir da relação entre carbono e nitrogênio orgânicos e seus isótopos estáveis ( δ 13 C e δ 15 N), e de petrografia. A quantificação das frações minerais foi realizada atrav és de espectrometria de infravermelho, e a identificação através de análises de difração de raios X na fração argilosa. A cronologia foi realizada a partir de data ções radiocarbônicas ( 14 C) AMS. Os registros sedimentares de ambos os testemunhos analisados m ostraram a alternância entre ambientes de características deposicionais de maior e de menor energia hidrodinâmica. As diferenças apresentadas na sedimenta ção dos testemunhos estão relacionadas com a migração lateral do canal principal de um braço do Rio Negro que passa pelo Lago Acarabixi. Esses registros mostraram quatro fases de sedimentação: 9500-8100 14 C AP; 8100-7400 14 C AP; 7400-1600 14 C AP, e 1600 14 C AP–Presente. A ausência de registro sedimentar na terceira fase pelo test emunho ACA 02/03, está relacionada a fortes eventos de inundação, teriam remo vido o sedimento no testemunho ACA 02/03, que se localizava neste período m ais próximo do canal principal de corrente. A análise da matéria orgânica i ndicou origem pedogênica. Ela seria oriunda da lixiviação de solos podzólicos da bacia do Rio Negro, e transportada pelo Rio Negro e depositada junto com o sedimento no L ago Acarabixi. De modo geral, a planície de sedimentação estudada no Rio Negro demon strou ser um ambiente em que os centros de sedimentação variam ao longo do temp o. Estes centros de sedimentação estariam relacionados ao deslocamento latera l dos canais principais de correntes dos rios, além de seu preenchimento pelas ench entes. Podem ser reconhecidas duas fases neste preenchimento: uma fase de for te deposição com migração lateral dos canais até 8000 anos e uma fase de sedimentação mais lenta com características mais lacustres após 8000 anos AP / Knowing that the hydrologic conditions of a fluvial sy stem depends directly on the regional climate, and that the Holocene climatic chang es reached several areas of Amazonia in different ways, this work seeks to reconstitute , through studies of lacustrine survey, the paleoenvironment and the hydrologic condit ions active during Holoceno in the lake Acarabixi, located in the sedimentary plain of medium Rio Negro. The characterization of the litologics units was accomplished th rough density measures, % in water, organic matter, granulometry, and material she ets to silt up rude. The origin of the organic matter was evaluated starting from the relatio nship between carbon and organic nitrogen and δ 13 C and δ 15 N, and of petrografy. The quantification of the mine ral fractions was accomplished through infrared-espectrometry, and the identification through analyses of diffraction of rays X in the loamy fractio n. The chronology was accomplished starting from datings radiocarbônicas ( 14 C) AMS. The sedimentary registrations of both analyzed core showed the alternation among environmen ts from smaller and bigger hydrodynamic energy. The differences presented in the sedimentation of the core are related with the lateral migration of the main chann el of an arm of Rio Negro that goes by the Lago Acarabixi. Those registrations showed four sedimentation phases: 9500- 8100 14 C AP; 8100-7400 14 C AP; 7400-1600 14 C AP, and 1600 14 C AP-present. The absence of sedimentary registration in the third phase for the core ACA 02/03, is related to strong flood events, they would have removed the se diment in the core ACA 02/03, that was located closer of the main channel of current i n this period. The analysis of the organic matter indicated pedogenic origin. The organic matter would be originating from of the ‘ lixiviação’ of podzóls of Rio Negro basin, and transported by Rio Negro and deposited with the sediment in the Lago Acarabixi. In general, the sedimentation plain studied in Rio Negro demonstrated to be an environme nt in that the sedimentation centers vary along the time. These sedimentation cente rs would be related to the lateral displacement of the main channels of currents of the riv ers, besides it’s completion for the flooding. Two phases can be recognized in this comple tion: a phase of strong deposition with lateral migration of the channels to 8 000 years and a phase of slower sedimentation with more lacustrine characteristics after 8000 years AP.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-06-28T18:00:50Z No. of bitstreams: 1 moreira, 2008.pdf: 3355865 bytes, checksum: 22ec01a744345548acc67908e25fcd32 (MD5) / Made available in DSpace on 2017-06-28T18:00:50Z (GMT). No. of bitstreams: 1 moreira, 2008.pdf: 3355865 bytes, checksum: 22ec01a744345548acc67908e25fcd32 (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / A Bacia Amazônica é acompanhada, ao longo do curso dos seus rios, por planícies de inundação. Sabe-se que estas regiões apresentam um grande potencial no armazenamento de matéria orgânica, que por sua vez, reservam importantes informações sobre mudanças climáticas ocorridas no passado. O conhecimento destas alterações pretéritas permite o entendimento de como os ecossistemas podem reagir a futuras mudanças no clima. Tendo em vista estas características, o objetivo deste estudo é reconstruir as mudanças pal eoambientais e paleohidrológicas do Lago Santa Ninha, na Várzea do Lago Grande de Curuai, localizada na margem direita do Rio Amazonas, à apr oximadamente 850 km da foz. Foram analisados dois testemunhos, denominados como TA12 e TA14 que apresentam, respectivamente, 2,10 e 2,70cm de compr imento. A determinação do teor de água, densidade aparente, granulometria e m ineralogia permitiram reconstruir a hidrodinâmica da região. A análise da composição da matéria orgânica, através da concentração de carbono e nitrogênio e d os isótopos estáveis δ 13 C e δ 15 N indicaram as alterações na vegetação e as dataçõe s por carbono 14 revelaram que o testemunho TA14 apresenta 5700 anos cal AP. E ste estudo colocou em evidencia diferentes ambientes sedimentares: na bas e do testemunho até 5000 anos cal AP temos uma vegetação inundada que foi gr adualmente substituída por bancos de gramíneas e por uma planície com secas sa zonais em 4000 anos cal AP até alcançar, desde 700 anos AP as condições atuais deste lago. Essas mudanças são interpretadas como a resposta a um aumento do n ível da água do rio durante as enchentes, que por sua vez são conseqüências de alt erações climáticas ocorridas na região / Amazonian Rivers are accompanied, during their cour se, by floodplains, which are named “várzeas”. It is known that these regions hav e a great potential in the storage of organic matter, which in turn, provides importan t information about climate change occurred in the past. Knowledge of these changes al lows the understanding of how ecosystem may respond to future changes in climate. The physical, chemical and geochemical characteristics of lacustrine sediments were studied to reconstructed paleohydrological control on sedimentation in an Am azonian floodplain. Two cores were collected at the Lago Grande de Curuai floodpl ain, in Santa Ninha lake, located on the right margin of the Amazon River at 850km of the estuary. Water content, granulometry, radiocarbon datation, microscopic ana lyses, organic carbon and nitrogen content and δ 13 C were used to characterize the sedimentary process es. The core TA12 is 210 cm-long and the TA14 has 270cm tha t correspond to 5700 years cal BP. The core points out different sedimentary environments: a flooded vegetation at the base of the core till 5000 cal yrs BP is sub stituted by graminea banks changing to a floodplain encompassing prolonged annual dryne ss at 4000 cal yrs BP. Since 700 BP the present day varzea lake, permanently ove rflooded, has been installed. These changes are interpreted as a response to an i ncrease in the level of water in the river during the floods, which in turn are cons equences of climate change occurring in the region

In this study, litho-, bio- and chronostratigraphic investigations combined with RTK GPSleveling have been carried out to reconstruct the paleoenvironment in the central part of theLånghundraleden Trail. The area displays four shallow lake basins of varyingmorphologies. The basins are now covered with peat as a result of infilling and overgrowth.The emergence of the saddle-point, i.e. the highest point of the underlying minerogenicsurface, was estimated to have occurred c. BC/AD. The isolation events of two basins, atc.12.4 and c.12.3 m a.s.l. west and east of the saddle-point, were dated to c.AD 20 andc.AD 30, respectively. By combining these isolation data with six previously investigatedbasins a shore displacement curve for the central part of the Långhundraleden Trail and thesurrounding area, i.e. east of the Ekoln basin was constructed. The curve indicates anaverage regressive shore displacement rate of c.6.2 mm/yr since c. 3200 BC. Around 1500BC, this trend was interrupted by a short period of retarded regression, correlated with theL4 event. The isolation ages of the basins in the Långhundraleden Trail appears relativelyyoung when compared to an average shore displacement rate of 5.6 mm/year in thenorthern part of L. Mälaren, west of the Ekoln basin. As the area is dominated by a fissurevalleylandscape, this discrepancy could be attributed to small-scale irregular tectonicmovements, which caused faster uplift rate, i.e. 6.2 mm/year, east of the Ekoln basin.

Discriminer l'influence des activités humaines de celle des processus naturels sur les changements environnementaux récents est un enjeu scientifique important. Dans ce but, les mollusques et les foraminifères fossiles des Pertuis Charentais (ouest de la France) ainsi que les sédiments déposés pendant l'Holocène dont ils sont issus ont été étudiés. L'objet d'étude central est un drapage vaseux qui constitue une grande partie du comblement sédimentaire terminal des Pertuis. Les résultats obtenus montrent qu'il est composé de sédiments fins d'origine continentale déposés à partir de 1400 AD. Il est la conséquence d'une augmentation de l'érosion des sols, favorisée par la déforestation entreprise au Moyen-Age. Le taux de sédimentation de cette vase a augmenté brutalement, suite à une période d'augmentation des précipitations hivernales à la fin du Petit Age Glaciaire qui a accéléré l'érosion des sols sur ces territoires fragilisés car déforestés. Le dépôt brutal de sédiments fins dans les Pertuis Charentais a eu peu de répercussions sur les communautés de mollusques benthiques, excepté l'extinction locale du bivalve \textit{Lepton squamosum} de la baie de Marennes-Oléron. En revanche, l'augmentation des apports sédimentaires a été à l'origine d'une succession écologique au sein des communautés de foraminifères (résistance - perturbation - adaptation). Les résultats obtenus démontrent comment des milieux perturbés par les activités humaines deviennent plus sensibles aux changements climatiques. Ils soulignent aussi le potentiel de la paléoécologie dans la compréhension des changements environnementaux récents dans les zones côtières à une échelle millénaire à séculaire. / Unraveling the respective influence of human activities and natural processes on recent environmental changes is a critical issue. In this respect, fossil molluscs and foraminifers of the Pertuis Charentais area (western France) as well as the sediments deposited during the Holocene they originate from have been studied. The study is focused on a mud drape that corresponds to the upper, most recent sediment infill of the area. The results show that it is composed of fine grained sediments originating from the adjacent catchments deposited from 1400 AD onwards. This major environmental change was the consequence of an increase in soil erosion promoted by intense deforestation started during the Middle Ages. Mud sedimentation rate increased suddenly in ca. 1760 AD, owing to a short-lived increase of winter rainfall which triggered more intense soil erosion on vulnerable deforested lands. The sharp deposition of fine grained sediments in the Pertuis Charentais has had few consequences on the past benthic mollusc communities, except the local extinction of the bivalve \textit{Lepton squamosum} in the Marennes-Oléron Bay. On the contrary, the increase in mud supply has triggered an ecological succession among benthic foraminifer communities (resistance - disturbance - adaptation). As a whole, the results demonstrate that environments disrupted by human activities become more sensitive to high-frequency climate changes. They also highlight the potential of paleoecology for a better understanding of recent environmental changes occurring within coastal areas at a millennial to centennial scale.

Ce travail de recherche porte sur l’étude du paléo-environnement du massif des Calanques, sur la mise en place d’une structure karstique de surface (poljé de Cassis, SE France) et sur l’empreinte de l’Homme sur son milieu. L’étude se base sur la réalisation de mesures géophysiques (électrique, gravimétrie, sismique passive) et sur l’analyse de plusieurs sondages, dont le principal est un enregistrement sédimentaire de 50 m de long carotté dans un paléo-lac situé à 2 km du littoral méditerranéen qui retrace le paléo-environnement du massif des Calanques au Pléistocène supérieur et à l’Holocène.Le paléo-lac de Cassis a été formé par la dissolution du calcaire barrémien et/ou par l’effondrement d’une cavité karstique, et a été rempli par une sédimentation laminée fine issue de l’érosion des marnes aptiennes, sédimentation qui caractérise un milieu de dépôt anoxique profond. Les observations spéléologiques et les analyses sédimentaires supposent l’existence d’une connexion entre le poljé et la rivière souterraine du Bestoaun.L’environnement holocène, stable sur toute la période holocène, est dominé par les formations herbacées sèches. L’impact de l’Homme sur l’environnement du massif des Calanques est visible au travers des modifications du réseau hydrographique local, de la métallurgie du plomb et de la mise en place de pratiques agro-pastorales. / This Phd research work focuses on : (1) paleo-environment of the Calanques, (2) karst structure formation (polje of Cassis, SE France) and (3) Holocene environmental changes linked to human activities.The study is based on a multi-geophysical methods approach (electrical resistivity tomography, gravimetric, passive sismic survey) and on several sedimentary records studies. The main sedimentary record is 50 m-long core coming from a pleistocene paleolake located 2 km from the Mediterranean Sea. Limestone dissolution and/or cavity collapse led to the development of a polje, rapidly filled by the erosion of Aptian marls in glacial period. The connection between the polje and the three kilometer long Bestouan underwater karstic conduit with submarine outlet is strongly suggested by sedimentological studies and geophysical prospections.The Holocene environment is dominated by dry herbaceous formations. Human activities impact on the environment is visible through (1) local water network changes, (2) lead metallurgy activity and (3) agro-pastoral practices.

The thermal maturity of sediments from the upper Cambrian to lower Ordovician Mila and Ilbeyk  formations in the Zagros Basin in southwestern Iran is evaluated in this thesis. A number of low-cost,  fast, optical evaluation methods are utilised to assess their effectiveness for providing accurate, well  constrained thermal maturity results. Palynomorph colours under transmitted light are measured using  two optical evaluation methods (Palynomorph Darkness Index , PDI- Goodhue & Clayton 2010;  Acritarch Alteration Index, AAI- Legall et al., 1981) to study 540 acritarchs of three acritarch  morphotype-groups: acanthomorphs, Cristallinium-type and veryhachides. Correlation of the PDI and  AAI results collected in this study with UV fluorescence and rock-eval pyrolysis data taken from  previous studies suggests that the studied sediments are within the wet gas thermal maturity window.  Furthermore, investigating the PDI results of acritarchs allowed for the identification of reworked or  recycled acritarchs. Investigation of the stratigraphy of strata containing abundant reworked or recycled  acritarchs allowed for the identification of a ravinement surface in a transgressive shallow water  depositional environment in the studied strata.

[pt] Estudos paleoambientais sobre reconstruções climáticas no pretérito ajudam a compreender os processos biogeoquímicos atuais e, portanto, fornecem subsídios ao atual cenário de mudanças globais. As principais ferramentas utilizadas nesses estudos envolvem indicadores que requerem a integração de informações geoquímicas, geomorfológicas, oceanográficas e biológicas. No presente trabalho, dois testemunhos (RJ13-01 e RJ13-02) foram coletados na plataforma continental do Rio de Janeiro na isóbata de 100-m e datados através dos métodos de 210Pb e 14C, englobando, respectivamente, 14,5 cal kyr BP e 5,3 cal kyr BP. O objetivo principal do trabalho foi investigar o efeito de variáveis climáticas e ambientais sobre o aporte de material autóctono e alóctono na plataforma continental do Rio de Janeiro. Foram considerados dados geofísicos, granulometria, elementos traços (V, Cr, Mn, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Ba, Tl, Pb e U), elementos majoritários (Ca, Si, Al e Fe), nitrogênio total (TN), carbono orgânico total (TOC), carbonato de cálcio (CaCO3), hidrocarbonetos alifáticos (n-alcanos) e hidrocarbonetos aromáticos (HPAs), assim como consideradas razões entre elementos e compostos que indicam a introdução de material continental e biogênico, razões redox e de produtividade, além de marcadores de tipo de vegetação e de combustão. Os resultados ressaltaram três fases deposicionais na área estudada: a primeira fase vai de 14,5 cal kyr BP à 7,5 cal kyr BP, e se caracteriza pela ocorrência de granulometria média a grosseira, fragmentos de conchas, alto teor de Si (27 porcento), alto aporte de material biogênico Ca/Al (3,00), altos valores (30,5) de ACL (tamanho médio da cadeia n-alcanos) e alta contribuição de HPAs pirogênicos (33 porcento), por volta de 8,0 cal kyr BP, indicando maior incidência de clima seco na maioria dos períodos, além de ser marcada por níveis do mar mais baixos. A segunda fase, entre 7,5 cal kyr BP e 4,5 cal kyr BP, mostrou influência das Águas Centrais do Atlântico Sul (SACW), marcada por um máximo de elevação do nível do mar, eventos de seca com maior intensidade de incêndios naturais com alta contribuição de HPAs pirogênicos de 5-6 anéis (68 porcento), entre 6,1 cal kyr BP e 4,1 cal kyr BP, e alto aporte de material continental Al/Ca (0,69); Fe/Ca (0,27) e alta produtividade. A terceira fase cobre o Holoceno superior, a partir de 4,5 cal kyr BP até o presente. Nessa fase, foram encontrados fluxos mais elevados de matéria orgânica, entre 3,2 cal kyr BP a 3,3 cal kyr BP (RJ13-01) e 3,4 cal kyr BP (RJ13-02), como indicado por TN, TOC, Ni, Cu, Zn, HA e HPAs, e um maior aporte continental, devido aos altos valores de razões redox-sensíveis a partir de 2,5 cal kyr BP no RJ13-01 e ao longo do testemunho RJ13-02. Esses fatores provavelmente são decorrentes do deslocamento da Zona de Convergência Intertropical (ITCZ) mais ao sul, deixando o clima mais úmido na Amazônia, a intensificação do SAMS trazendo umidade para SE do país através da SACZ. Porém, também podem refletir um evento de menor nível do mar, que influenciou nos níveis de oxigênio na coluna d água. Por outro lado, indicadores de clima seco (ACL, HPAs pirogênicos de 5-6 anéis) sugerem que houve oscilações entre clima úmido e seco ao longo do Holoceno superior. Desta forma, os indicadores orgânicos e inorgânicos considerados nos testemunhos da plataforma continental do RJ possibilitaram avaliar e corroborar dados de outros estudos sobre os eventos climáticos ocorridos nos últimos 14 mil anos no SE do Brasil, e suas relações com fatores como: variações no nível do mar, mudanças na ITCZ, intensificação da SAMS influenciando a SACZ, mudanças nos padrões de ventos e na Corrente do Brasil; influência da SACW mais no sentido S-W do sistema de ressurgência de Cabo Frio; variações climáticas com registros de incêndios naturais e variações da vegetação; além de registros que podem ser relacionados à ocupação humana. / [en] Paleoenvironmental studies on climate reconstructions in the past help to understand the current biogeochemical processes and therefore become increasingly important in the current scenario of global changes. The main parameters used in these studies involve proxies that require the integration of geochemical, geomorphological, oceanographic and biological information. In this study two cores (RJ13-01 and RJ13-02) were collected on the continental shelf of Rio de Janeiro in the isobath 100-m and dated by 210Pb and 14C methods covering14.5 cal kyr BP and 5.3 cal kyr BP, respectively. The main goal of this work was to investigate the effect of climatic and environmental variables on the autochthonous and allochthonous material inputs in the continental shelf of Rio de Janeiro. For this, geophysical properties, grain size, trace elements (V, Cr, Mn, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Ba, Tl, Pb and U), major elements (Ca, Si, Al and Fe), total nitrogen (TN), total organic carbon (TOC), calcium carbonate (CaCO3), aliphatic hydrocarbons (n-alkanes) and polycyclic aromatic hydrocarbons (PAHs) were considered jointly with continental and biogenic input proxies, redoxsensitive and productivity proxies besides vegetation type and combustion proxies. Results highlighted three periods: the first period (from 14.5 to 7.5 cal kyr BP) with the occurrence of mean grain size of the sediment, shell fragments, high content of Si (27 percent), high input of biogenic material Ca/Al (3.00) and high ACL (average chain length) values (30.5). In addition to high contribution of pyrogenic PAHs (33 percent) around 8.0 cal kyr BP indicating higher incidence of dry weather in most periods; marked by a low sea level. The second period between 7.5 cal kyr BP and 4.5 cal kyr BP showed the influence of the South Atlantic Central Waters (SACW) marked by a maximum transgression of the sea, drought events with greater intensity of wildfires with high contribution of pyrogenic PAHs of 5-6 rings (68 percent) between 6.1 and 4.1 cal BP kyr BP and high input continental materials Al/Ca (0.69); Fe/Ca (0.27) and high productivity. The third period covers the late Holocene from 4.5 cal kyr BP to present. In this period, higher fluxes of organic matter were found between 3.2 cal kyr BP to 3.3 cal kyr BP (RJ13-01) and 3.4 cal kyr BP (RJ13-02), as indicated by TN, TOC, Ni, Cu,Zn, n-alkanes and PAHs, and higher continental input due to high redox-sensitive proxies from 2.5 cal kyr BP in RJ13-01 and along RJ13-02. These factors are probably related to the displacement further south of the Intertropical Convergence Zone (ITCZ), which brought humidity to Amazon, the intensification of SAMS bringing humidity to SE of Brazil trought SACZ. Also has been marked by the decrease in sea level which influenced the oxygen levels in the water column. On the other hand, dry climate indicators (ACL, pyrogenic PAHs with high molecular weight) suggest that there were fluctuations between wet and dry climate along the late Holocene. Thus, the organic and inorganic proxies considered on the cores of continental shelf of Rio de Janeiro allowed to evaluate and corroborate the data of other studies of climate events over the past 14,000 years in SE Brazil and their relation to the facts such is the variations in the sea-level, chances in ITCZ, the intensification of SAMS and SACZ, changes in wind pattern, and in the Brazilian current; influence of the SACW further S-W of the Cabo Frio upwelling system; and climate variations with records of wildfires and variation on the vegetation; in addition to records that could be related to human occupation.

Detailed geochemical analysis of the turbidite-associated shales of the Cretaceous Katafito Formation, Greece, reveals important details regarding the paleoenvironment, paleoproductivity, and regional tectonics of the Pindos Basin. The Katafito Formation was deposited along an active margin at the early onset of closure of the Tethys Sea in the Pindos sub-basin. While careful studies of the coarse clastic component of turbidites are common, this study consisted of a detailed geochemical characterization of the fine-grained portions, which helped reveal paleoenvironmental information about the basin. This study combined organic and inorganic geochemistry utilizing elemental, mineralogical, and organic chemical signatures from fine-grained turbidite-associated sediments across six regional outcrops; three in the Peloponnese region and three in the Eprius region of Greece. In addition, shales from two outcrops associated with shallow marine deposits were sampled from Crete in the absence of identified turbidite outcrops and were used as reference point for geochemical indicators. In total 117 shale samples were analyzed via X-ray florescence (XRF) for elemental quantification, X-ray powdered diffraction (XRPD) for quantitative phase analysis of the minerals present, and Rock-Eval Pyrolysis for organic quality and type. Chemical trends between northern and southern outcrops reveal details about the tectonics, climate, and ocean circulation of the Pindos sub-Basin during the Cretaceous. Potassium feldspar and plagioclase feldspar show distinct trends between northern and southern outcrops, with a relative decrease in plagioclase to the north despite the source terrain becoming more mafic toward the north. This decrease in plagioclase to the north could show that the mountains were more developed in the north during the Cretaceous, leading to a higher orographic effect and the resulting increase in precipitation rates and the associated increase in weathering rate. Geochemical proxies for paleo-oxygenation (U/Th, V/Cr, Authigenic uranium, and degree of pyritization) are similar in abundance between northern Pindos, southern Pindos, and Crete samples, but using a Kolmogorov-Smirnov test at the 99% confidence level, these proxies show that the northern part of the basin was more oxic than the south at the time of deposition. This is interpreted to show that although the Pindos Basin waters were still well-oxygenated and in communication across the study area, the early signs of tectonic constriction were beginning to be seen in the north during the Late Cretaceous. Most samples contain less than 0.5% total organic carbon (TOC) based on Rock-Eval analysis, with a median of 0.36% and IQR of 0.29-0.47%. This could be the result of either low primary productivity or efficient recycling of organic matter in oxic conditions. However, paleo-TOC indicators such as nickel enrichment suggest that total organic carbon was likely 2-3% higher at time of deposition, which, given the interpretation that waters were dominantly oxic, suggests high primary productivity rates at the time of deposition. The large discrepancy between original and preserved TOC is at least partially explained by the high thermal maturation of the samples (Tmax median of 591°C and IQR of 594-437°C), suggesting that hydrocarbons have been generated and migrated out of the shales. Lastly, based on elevated calcium carbonate concentrations measured in shale samples and common preservation of detrital carbonate grains in the associated turbidite sandstones, along with the regional prevalence of time-equivalent limestones preserved across much of Greece and the broader region, it is interpreted that the turbidites of the Katafito Formation were deposited basinward of a well-developed carbonate shelf, and that siliciclastics were efficiently transported across this shelf through well developed and focused transport fairways.