Marine sediment samples were collected from Quebrada la Higuera, Chile to provide a record of planktonic and benthic foraminifera as a means of reconstructing the paleo-bathymetry and paleo-environment of the Quebrada la Higuera basin. The research area is located in northern Chile, south of Caldera in Quebrada la Higuera (S 27° 16.443, W 70° 54.887). The Quebrada la Higuera basin rests unconformably atop Mesozoic gabbroic basement, which is locally exposed, representing fault-bounded horsts and grabens. At the base of the section, diatomaceous sediment within the sequence suggests intervals of high productivity. The co-occurrence of the shallower water benthic species Nonionella miocenica and Epistominella pulchella with deep-water species Bolivina tumida, Uvigerina peregrina, Globobulimina auriculata, and Bolivina subfusiformis, at 10-23 m above the base of the section and again at 44-62 m, within fining-upward sedimentary packages suggests possible turbidites caused by transgressive-regressive cycles. Additionally, the occurrence and high abundance of these species are indicative of high productivity. A 30-40 cm Late Miocene phosphatic bed consisting of vertebrate and invertebrate fossils lies unconformably atop a poorly consolidated sand ~42 m from the base of the section. This phosphatic bed suggests that upwelling was occurring off the coast of Chile earlier than previously believed. The hyperaridity of Chile's Atacama Desert has been the result of the cold upwelling Peru-Chile current, which is further intensified by the rain-shadow effect of the Andes and the cold, dry descending Hadley cell. The occurrence of planktonic foraminifer Globigerina bulloides at the base of the section establishes the maximum possible lower age limit of 15.97 Ma (Middle Miocene). At 47 m, the co-occurrence of Globorotalia margaritae, Globorotalia crassaformis, and Dentogloboquadrina altispira establishes a maximum age limit for that horizon of ~3.6 Ma (Early Pliocene), providing an age range for the Quebrada la Higuera section from Middle Miocene through Early Pliocene. This study provides a record of planktonic and benthic foraminifera as a means of reconstructing the paleohistory of Quebrada la Higuera and more broadly through the Caldera region. The analyses address interactions between uplift, atmospheric conditions, sea level, and upwelling within the region from interpretations of the composite section, including facies relationship between sediments and occurring foraminifera species. These observations, along with the foraminiferal record, help broaden the understanding and development of the Quebrada la Higuera Neogene record.

Orientador: Hans Dirk Ebert / Banca: Ricardo Latgé Milward de Azevedo / Banca: Cláudio Coelho de Lima / Resumo: As pesquisas em geociências tendem cada vez mais a utilizar grande volume de dados heterogêneos, cuja interpretação integrada é complexa devido ao envolvimento de diferentes parâmetros, bem como de relações temporais e espaciais. As técnicas de computação gráfica e visualização científica assumem importância crescente por permitirem representar e manipular dados geológicos tal como são e estão no espaço, isto é, em 3D. Esta dissertação teve por objetivo utilizar ferramentas computacionais para modelar geometricamente e visualizar dados geológicos. Utilizando o programa GOCAD foram construídas superfícies paleobatimétricas das bacias de Santos e Campos para o meso- Neocretáceo a partir dos dados disponíveis na literatura. Sua integração com dados litológicos e estruturais em um único ambiente de visualização 3D permitiu aumentar o potencial de interpretação dos dados originalmente representados em mapas bidimensionais. Para melhor contextualizar a evolução paleogeográfica destas bacias durante a abertura do Atlântico Sul e representar analogias com ambientes de deposição atuais foram construídas superfícies batimétricas do Atlântico Sul do mesocretáceo ao recente e do Mar Vermelho. A partir da utilização de ferramentas de modelagem e visualização 3D de domínio público (VTK) foi desenvolvido um programa computacional (Tensor3D) para a simulação da deformação de objetos geológicos, desde rochas, estruturas tectônicas, domos de sal até bacias, a partir da modificação dos componentes de cisalhamento simples e puro contidos em tensores de deformação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Research in Geosciences is currently using extensive volumes of heterogeneous data, whose integrated interpretation is complex due to the involvement of different parameters, as well as time and spatial relationships. Computer graphics and scientific visualization techniques are assuming increasing importance as they allow the representation and manipulation of geologic data exactly as they appear in 3D space. The purpose of this work is using computational tools in order to geometrically model and visualize geologic data. Using the GOCAD program, mid-Early Cretaceus paleobathymetric surfaces have been constructed for the Santos and Campos basins, based on published data. Their additional integration with lithologic and structural data in a unified 3D visualization environment, allowed an increase in the interpretative potential of data originally represented using 2D maps. In order to provide a more general context for the paleogeographic evolution of these basins during the opening of the South Atlantic Ocean, and to represent analogies with current depositional environments, paleobathymetric surfaces have been modelled for the South Atlantic Ocean, from mid- Early Cretaceous to present time, and for the present Red Sea. By using 3D open-source modelling and visualization tools (VTK), a computational program (Tensor3D) has been devoloped to simulate deformation of geologic objects, from rocks, tectonic structures, salt domes to basins. This process is controlled by modifyng simple and pure shear components contained in strain tensors... (Complete abstract, click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:26:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-10-28Bitstream added on 2014-06-13T19:13:13Z : No. of bitstreams: 1 lavorante_lp_me_rcla.pdf: 8726262 bytes, checksum: 7e256344a5ee4b910a8250a0774717ae (MD5) / Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) / As pesquisas em geociências tendem cada vez mais a utilizar grande volume de dados heterogêneos, cuja interpretação integrada é complexa devido ao envolvimento de diferentes parâmetros, bem como de relações temporais e espaciais. As técnicas de computação gráfica e visualização científica assumem importância crescente por permitirem representar e manipular dados geológicos tal como são e estão no espaço, isto é, em 3D. Esta dissertação teve por objetivo utilizar ferramentas computacionais para modelar geometricamente e visualizar dados geológicos. Utilizando o programa GOCAD foram construídas superfícies paleobatimétricas das bacias de Santos e Campos para o meso- Neocretáceo a partir dos dados disponíveis na literatura. Sua integração com dados litológicos e estruturais em um único ambiente de visualização 3D permitiu aumentar o potencial de interpretação dos dados originalmente representados em mapas bidimensionais. Para melhor contextualizar a evolução paleogeográfica destas bacias durante a abertura do Atlântico Sul e representar analogias com ambientes de deposição atuais foram construídas superfícies batimétricas do Atlântico Sul do mesocretáceo ao recente e do Mar Vermelho. A partir da utilização de ferramentas de modelagem e visualização 3D de domínio público (VTK) foi desenvolvido um programa computacional (Tensor3D) para a simulação da deformação de objetos geológicos, desde rochas, estruturas tectônicas, domos de sal até bacias, a partir da modificação dos componentes de cisalhamento simples e puro contidos em tensores de deformação... / Research in Geosciences is currently using extensive volumes of heterogeneous data, whose integrated interpretation is complex due to the involvement of different parameters, as well as time and spatial relationships. Computer graphics and scientific visualization techniques are assuming increasing importance as they allow the representation and manipulation of geologic data exactly as they appear in 3D space. The purpose of this work is using computational tools in order to geometrically model and visualize geologic data. Using the GOCAD program, mid-Early Cretaceus paleobathymetric surfaces have been constructed for the Santos and Campos basins, based on published data. Their additional integration with lithologic and structural data in a unified 3D visualization environment, allowed an increase in the interpretative potential of data originally represented using 2D maps. In order to provide a more general context for the paleogeographic evolution of these basins during the opening of the South Atlantic Ocean, and to represent analogies with current depositional environments, paleobathymetric surfaces have been modelled for the South Atlantic Ocean, from mid- Early Cretaceous to present time, and for the present Red Sea. By using 3D open-source modelling and visualization tools (VTK), a computational program (Tensor3D) has been devoloped to simulate deformation of geologic objects, from rocks, tectonic structures, salt domes to basins. This process is controlled by modifyng simple and pure shear components contained in strain tensors... (Complete abstract, click electronic access below)

Masters of Science / Located on the western offshore on the Atlantic Ocean margin of Southern Africa, the Orange Basin is the youngest and largest of the South Africa’s seven sedimentary basins. This passive margin basin in known for its hydrocarbon potential and therefore is the focus of attraction of several oil exploration companies. The study area lies near the continental margin in which four exploratory wells were drilled. An attempt has been made in this work to understand the depositional settings of these reservoirs and their biostratigraphy. Distribution of important planktonic index foraminifera helps in dating the reservoir sections. Paleoecological studies of benthic foraminifera were used for understanding the prevailing environment during the Cretaceous period. The study indicates that most of the reservoirs are distributed in the Albian (Early Cretaceous) and a few in the Cenomanian age sediments. Relatively shallow shelf sedimentation prevailed in the Late Aptian to middle part of Albian with deposition of arenaceous units. There were periodic localised deepening as well as very shallow depositional condition leading to exposure (diastem) as indicated by lithology and faunal composition. Gradual rise in sea level started in Late Albian and the entire area was under bathyal environment till the end of Cenomanian stage. This is indicated by deposition of claystone rich units and the associated fossil benthics indicates deposition in slope area. The few relatively minor argillaceous sandstone and siltstone units are with poor reservoir quality.