This research investigates the character and significance of shelf-edge deltas within the sedimentary source-to-sink system, and how variability at the shelf edge leads to different styles of deep-water deposition. Because the shelf-edge represents one of the key entry points for terrigenous sediment to be delivered into the deep water, understanding of the sedimentary processes in operation at these locations, and the character of sediment transported through these deltas is critical to understanding of deep-water sedimentary systems. The research was carried out using three datasets: an outcrop dataset of 6000 m of measured sections from the Permian-Triassic Karoo Basin, South Africa, a 3D seismic data volume from the Eocene Northern Santos Basin, offshore Brazil and a dataset of 29 previously published descriptions of shelf-edge deltas from a variety of locations and data types. The data presented highlight the importance of sediment instability in the progradation of basin margins, and deep-water transport of sediment. The strata of the Karoo Basin shelf margin represent river-dominated delta deposits that become more deformed as the shelf-edge position is approached. At the shelf edge, basinward dipping, offlapping packages of soft-sediment-deformed and undeformed strata record repetitive collapse and re-establishment of shelf-edge mouth bar packages. The offlapping strata of the Karoo outcrops record progradation of the shelf margin through accretion of the shelf-edge delta, for over 1 km before subsequent transgression. The Eocene Northern Santos Basin shelf margin, in contrast, exhibits instability features which remove kilometers-wide wedges of the outer shelf that are transported to the basin floor to be deposited as mass-transport packages. In this example, shelf-edge progradation is achieved through „stable. accretion of mixed turbidites and contourites. The data also emphasize the importance of the role of shelf-edge delta processes in the delivery of sediment to the basin floor. A global dataset of 29 examples of shelf-edge systems strongly indicates that river domination of the shelf-edge system (as read from cores, well logs or isopach maps) serves as a more reliable predictor of deep-water sediment delivery and deposition than relative sea level fall as traditionally read in shelf-edge trajectories or sequence boundaries. / text

Le principal objectif de cette étude est de mieux comprendre et de quantifier les paramètres et les processus de contrôle de la morphologie et de l’évolution stratigraphique du nord du bassin de Santos pour les derniers 49,5 my. Il s’agit de déconvoluer le signal climatique et tectonique dans l’enregistrement sédimentaire à travers de l’analyse sismique à diverses résolutions (~7-8 s et ~400 ms de penetration), de l’analyse lithologique et le calage chrono stratigraphique des limites de séquence majeures, à partir de 19 forages industriels. La modélisation stratigraphique par Dionisos combinée à nos observations nous a permis de quantifier les paramètres majeurs qui vont contrôler l’architecture sédimentaire à différentes échelles de temps. 9 séquences stratigraphiques sont ainsi identifiées et regroupées en 3 mégaséquences (Mégaséquences A, B et C): (i) La Mégaséquence A est caractérisée par des systèmes deltaïques qui viennent remplir l’espace d’accommodation créé par le fluage du sel vers le bassin entre la baie de Guanabara et Cabo Frio. Le flux sédimentaire qui la nourrit est mis en relation avec le paléo fleuve du Paraíba do Sul qui se deplace vers le bassin de Campos à la fin du development de la Mégaséquence et resulte dans une drastique reduction des flux du bassin de Santos; (ii) La Mégasequence B est caractérisée par la rétrogradation de tous les systèmes sédimentaires comme une réponse directe à la diminution des flux sédimentaires. Cette megasequence est aussi caracterisée par l’implantation des depots contouritiques entre 30 et 21 Ma, problablement liés à des changements dans la circulation oceanique dû a l’ouverture de la passage de Drake et de la Tasmanie (entre 37 et 28 Ma); (iii) La Mégasequence C est caractérisée par une progradation et le déplacement des offlap breaks de 70 km vers l’océan, depuis les derniers 11.5 my comme réponse de l’augmentation de flux sédimentaire qui caractérise le passage à des cycles glacio-eustatiques marqués dans le Quaternaire. / The main objective of this study is to better understand and to quantify experimentally the main parameters that control the geomorphological and stratigraphic evolution of the Cenozoic sedimentary succession of the northeast Santos basin, Brazil, in the last 49.5 my. For this purpose, a variety of combining methologies were used, such as: seismic analysis of a dataset composed of different resolution levels (~7-8 s and ~400 ms penetration), chronostratigraphic and lithological data from 19 exploratory wells and stratigraphic modeling. Seismic analysis and stratigraphic modelling led to the identification of 9 main stratigraphic sequences that could be grouped into 3 megasequences (Megasequences A, B and C): (i) Megasequence A is characterized by deltaic features developed into a ramp feature located between Guanabara Bay and Cabo Frio. The formation of this delta resulted in a sedimentary overcharge that induced the basinward salt migration. The sedimentary input that feeds this delta was interpreted as related to an ancient Paraíba do Sul River that diversion to the Campos basin at the end of the megasequence development, resulting in a dramatically reduce the sedimentary influxes into Santos basin; (ii) Megasequence B is characterized by the retrogradational trend of sedimentary systems that offset offlap break of surfaces developed at 30 and 21 Ma about 78 km landward. This megasequence is also characterized by the beginning of conturites deposition related to the changes of oceanic circulation due to the opening of Drake and Tasmanian passages; (iii) Megasequence C is characterized by progradational systems that resulted in the coastline shift about 70 km oceanwards, in the last 11.5 my. The dominant progradational trend of this sequence is interpreted as a response of the increase in the sedimentary influx rate intensified by the spectral characteristics and amplitude of the glacial-induced eustatic signal that characterizes the Quaternary period.

O objetivo da presente tese é o de documentar, em escala milenar, as variações paleoclimáticas e paleoceanográficas superficiais do Atlântico Sul Ocidental desde o Último Máximo Glacial. Com esta finalidade, foram obtidas estimativas de paleotemperatura, paleossalinidade e paleoprodutividade baseadas na análise de fauna de foraminíferos planctônicos, isótopos estáveis de oxigênio e carbono em Globigerinoides ruber e nove datações de radiocarbono em amostras de um testemunho coletado na Bacia de Santos. Os dados foram complementados com a reanálise de outro testemunho previamente coletado em outro setor da mesma Bacia. Os resultados demonstram que as mudanças paleoceanográficas registradas no período analisado podem ser parcialmente explicadas por variações na exportação de calor e sal para o hemisfério norte relacionadas à atividade da célula de transporte meridional e à configuração das correntes superficiais associadas à circulação atmosférica. Outra parte significativa da variabilidade parece estar relacionada à intensidade do Sistema de Monção da América do Sul resultante de variações na insolação de acordo com o ciclo de precessão. Os principais desvios da tendência de variação da composição isotópica da água do mar esperada em função das mudanças de insolação coincidem com os grandes pulsos de degelo ocorridos em torno de 19, 14 e 8,2 mil anos AP. / The goal of this thesis is to document the paleoclimatic and paleoceanographic changes occurred at the millennial scale since the Last Glacial Maximum at the surface Western South Atlantic. Paleotemperature, paleosalinity and paleoproductivity estimates were obtained for this purpose based on faunal changes of foraminifera assemblages, carbon and oxygen stable isotopes in Globigerinoides ruber and nine radiocarbon datings in a core retrieved at Santos Basin. These data were supplemented by the reanalysis of a second core previously analyzed from a different sector of the same basin. The results demonstrate that paleoceanographic changes recorded in the analyzed period may be partially explained by changes in the heat and salt export to the northern hemisphere related to the meridional overturning cell and the surface currents related to atmospheric circulation. Another significant portion of the observed variability seems to be related to changes in the strength of the South American Monsoon System resulting from insolation changes according to the precessional cycle. The main departures from the expected trend of variation in the isotopic composition of seawater related to insolation changes coincide with great meltwater pulses occurred around 19, 14, and 8.2 kyr BP.

O objetivo da presente tese é o de documentar, em escala milenar, as variações paleoclimáticas e paleoceanográficas superficiais do Atlântico Sul Ocidental desde o Último Máximo Glacial. Com esta finalidade, foram obtidas estimativas de paleotemperatura, paleossalinidade e paleoprodutividade baseadas na análise de fauna de foraminíferos planctônicos, isótopos estáveis de oxigênio e carbono em Globigerinoides ruber e nove datações de radiocarbono em amostras de um testemunho coletado na Bacia de Santos. Os dados foram complementados com a reanálise de outro testemunho previamente coletado em outro setor da mesma Bacia. Os resultados demonstram que as mudanças paleoceanográficas registradas no período analisado podem ser parcialmente explicadas por variações na exportação de calor e sal para o hemisfério norte relacionadas à atividade da célula de transporte meridional e à configuração das correntes superficiais associadas à circulação atmosférica. Outra parte significativa da variabilidade parece estar relacionada à intensidade do Sistema de Monção da América do Sul resultante de variações na insolação de acordo com o ciclo de precessão. Os principais desvios da tendência de variação da composição isotópica da água do mar esperada em função das mudanças de insolação coincidem com os grandes pulsos de degelo ocorridos em torno de 19, 14 e 8,2 mil anos AP. / The goal of this thesis is to document the paleoclimatic and paleoceanographic changes occurred at the millennial scale since the Last Glacial Maximum at the surface Western South Atlantic. Paleotemperature, paleosalinity and paleoproductivity estimates were obtained for this purpose based on faunal changes of foraminifera assemblages, carbon and oxygen stable isotopes in Globigerinoides ruber and nine radiocarbon datings in a core retrieved at Santos Basin. These data were supplemented by the reanalysis of a second core previously analyzed from a different sector of the same basin. The results demonstrate that paleoceanographic changes recorded in the analyzed period may be partially explained by changes in the heat and salt export to the northern hemisphere related to the meridional overturning cell and the surface currents related to atmospheric circulation. Another significant portion of the observed variability seems to be related to changes in the strength of the South American Monsoon System resulting from insolation changes according to the precessional cycle. The main departures from the expected trend of variation in the isotopic composition of seawater related to insolation changes coincide with great meltwater pulses occurred around 19, 14, and 8.2 kyr BP.

[pt] No Brasil, a partir de Março de 2006 com a constatação de indícios de gás e condensado de óleo na Locação Paraty (poço 1-RJS-617D do bloco BM-S-10) e poucos meses depois, em Agosto, com a descoberta da acumulação de óleo (poço 1-RJS-628A do bloco BM-S-11, pioneiro da área atualmente declarada como LULA) nos reservatórios carbonáticos de idade Aptiana e localizados na camada Sub-Sal da Bacia de Santos, estes reservatórios adquiriram importância estratégica para o desenvolvimento econômico e tecnológico do Brasil. A pesquisa realizada neste projeto visa desenvolver metodologia para estimativa de cenários 3D de propriedades mecânicas elásticas estáticas de deformabilidade: módulo de elasticidade e coeficiente de Poisson e do fator de acoplamento fluído-mecânico: coeficiente de Biot-Willis, integradas ao dado sísmico e que destinam-se a alimentar simulador mecânico, mitigando incertezas e riscos econômicos e de SMS ao longo da vida produtiva dos diversos campos do PPSBS. O pioneirismo do presente estudo encontra-se em: (I) realização de inversão sísmica determinística CSSI (constrained sparse spike) baseada em modelo inicial de Impedância-P ao longo de toda a sequência estratigráfica da Bacia de Santos: Pós-Sal, Sal e Pré-Sal considerando o efeito do soterramento em dado sísmico 0-offset cedido pela ANP (Agência Nacional do Petróleo), (II) desenvolvimento de Modelo de Física de Rochas (MFR) para toda a sessão estratigráfica da Bacia de Santos, com base em perfis de poços cedidos pela ANP e furos geotécnicos, para estimativa das propriedades mecânicas elásticas dinâmicas a partir da Impedância-P obtida na inversão sísmica e (III) realização de ensaios mecânicos simultâneos em análogo mecânico (bloco de travertino romano) da camada Pré-Sal da Bacia de Santos para determinação de relação de equivalência estático vs. dinâmico, como também emprego de mais duas relações de equivalência estático vs. dinâmico advindas de trabalhos científicos totalizando três cenários de propriedades mecânicas de deformabilidade estáticas e de coeficiente de Biot-Willis. Como resultado foi constatado que os três cenários 3D de propriedades mecânicas elásticas estáticas de deformabilidade e coeficiente de Biot-Willis, herdaram o nível de detalhamento da sísmica HD (High Definition) empregada, a saber: resolução vertical de aproximadamente 35m e resolução horizontal de aproximadamente 600m. Ao comparar o mais rígido dos três cenários com o menos rígido deles, observou-se que o módulo de elasticidade estático chega a variar até 35 por cento, o coeficiente de poisson estático chega a variar até 22 por cento e o coeficiente de acoplamento fluídomecânico de Biot-Willis chega a variar até 8 por cento, sendo que a maior variação está especialmente nos carbonatos do Pré-Sal de idade Aptiana, nos carbonatos do Pós- Sal de idade Albiana e nos arenitos do Pós-Sal do Paleógeno e Cretáceo Superior. / [en] In Brazil, in March 2006, with evidence of gas and oil condensate in the Paraty location (well 1-RJS-617D of block BM-S-10) and a few months later, in August, with the discovery of oil accumulation (well 1-RJS-628A of the block BMS- 11, pioneer of the area currently declared as LULA) in the Aptian-age carbonate reservoirs and located in the Sub-Salt layer of the Santos Basin, these reservoirs have acquired relevance for the economic and technological development of Brazil. The research carried out in this project aims to develop methodology for estimating 3D scenarios of static elastic mechanical properties of deformability: modulus of elasticity and Poisson s coefficient and the fluid-mechanical coupling factor: Biot- Willis coefficient, integrated to the seismic data and destined to feed mechanical simulator, mitigating uncertainties and economic and SMS risks throughout the productive life of the various PPSBS deposits. The pioneerism of the present study is: (I) performing deterministic CSSI (constrained sparse spike) seismic inversion based on the initial P-Impedance model throughout stratigraphic sequence of the Santos Basin: Post-Salt, Salt and Pre-Salt taking into account burial depth effect on the seismic trace, (II) development of Rock Physics Models (RFM) for the entire stratigraphic column of the Santos Basin, based on well logs and geotechnical holes, in order to estimate the dynamic elastic mechanical properties from the PImpedance obtained in the seismic inversion and (III) realization of simultaneous mechanical tests on mechanical analogue rock (Roman Travertine block) of Santos Basin Pre-Salt layer to determine static vs. dynamic relation, as well as using two static vs. dynamic relations from scientific studies to build three scenarios of static elastic mechanical properties of deformability and Biot-Willis coeficient. As a result, it was verified that the three 3D scenarios of static elastic mechanical properties of deformability, as well as, Biot-Willis coeficient inherited the level of detail of the HD (High Definition) used seismic, that is: vertical resolution of approximately 35m and horizontal resolution of approximately 600m. When comparing the most rigid of the three scenarios with the least rigid, it is observed that the static elasticity modulus vary up to 35 percent, static poisson s ratio vary up to 22 percent and the Biot-Willis coefficient variy up to 15 percent. The greater variation is especially in the carbonates of the Pre-Salt of Aptian age, in the carbonates of the Post-Salt of Albian age and in the sands of the Pos-Salt of Paleogeno and Upper Cretaceous.