979 resultados para Subsurface


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The N6 Plateau presents an iron-ore occurence in Carajás Mineral Province, standing near to actually operating deposits. Geological mapping in 1:10,000 scale and integration of geochemical, geophysical, petrography and drilling turns possible interpretation of his geological evolution. The mapped area has lithotypes from Archean Grão Pará Group, comprising very lowgrade metamorphic basic rocks and iron formation and an Proterozoic sedimentary association of conglomeratic sandstones called as Caninana Unity. The structural geology in given by a regional scale homoclinal, where the Grão Pará Group strata dips towards SW, as a part of the Northern Limb of the Carajás Fold. Subsequent deformation associated to the installation of the Carajás Shear Zone presents as E-W fold axis. Geochemical evidence permits to consider de Parauapebas Formation as the rocks which has been hydrothermally-altered to outsourcing fluids responsible to deposition of iron formations in the oceanic system, including different signatures which can be interpreted as possible sub-embayments in the Carajás Basin. The iron ore in the area occurs in subsurface as very fine friable hematite generated by supergenous enrichment of the iron formation. The conceived geologic model differs from the current academic proposal on the fact that hydrothermal alteration has been involved on the jaspelite enrichment. Metamorphism on the Parauapebas Formation presents paragenesis considered as ocean-floor metamorphism which precedes de deformation insofar as the rocks show no tectonic fabric referring to shallow crust evolution. Geophysical methods such as magnetometry and gravimetry presents excellent results for structural interpretation in uneven exposed terrain

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This work aims to identify and photograph grains that compose important Cretaceous carbonate units of the Potiguar Basin, represented by the Ponta do Mel and Jandaíra formations (Albian-Campanian). Petrographic investigation of thin sections was essential. The samples studied come from wells and surface samples from the collection UNESPetro – UNESP, Rio Claro. In the Ponta do Mel Formation, the grains consist of ooids, oncoids, peloids and bioclasts. Regarding to the identified bioclasts, the solenoporacean red algae, mollusks (bivalves and gastropods), echinoids, foraminifera, ostracods and worms were the dominant elements. In the Jandaíra Formation, the grains are composed by ooids, peloids and bioclasts, which are represented by green algae, mollusks (bivalves and gastropods), benthic foraminifera miliolids, worms, echinoderms and ostracods. The grains found in the Ponta do Mel Formation are somewhat similar to those found in the Jandaíra Formation, with the exception of calcareous algae. The subsurface material from the Ponta do Mel Formation is derived from the upper part of the unit, representing marine high-energy carbonates, which also contains ooids and Trocholina. The samples of Jandaíra Formation, collected in outcrops, often contain green algae, mollusks and miliolids, and come from inner shelf and lagoon facies previously described

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The geophysical methods are used as tools that, together with other data, assist in target detail and sizing of ore bodies. This paper presents the results of the application of DC resistivity geophysical method on a manganese mineral occurrence located in Itapira, in the northern portion of São Paulo state, hosted predominantly in schists and quartzits of Itapira Group. The integration of geophysical data resulted in the elaboration of electrical resistivity models, where it was possible observe that the mineralized body, composed predominantly of manganese oxides and hydroxides, has a pattern of high resistivity (above 5000 Ω.m) both surface and subsurface. The contrast with the host rock is characterized mainly by different minerals assemblages and by the presence of local groundwater. The results accomplished in this paper reveal that the application of DC resistivity method is valid in primary evaluations of supergene deposits

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Due to the new discoveries of oil and gas reservoirs, and also the increasing production of bio-fuels, the brazilian general pipeline system is being vertiginously extended. On the other hand, there is a lack of clear parameters that would allow a better utilization of the geological-geotechnical studies in the process of environmental licensing of pipeline systems. Therefore, this paper presents guidelines that would orientate the environmental licensing procedures to build pipeline systems, and also the geological-geotechnical studies that would support the characterization of the physical context. The method applied in this study consisted in the existing data survey and in their organization, analysis and review. In doing so, there is a well-subsidy integration of the many steps of the pipeline system implementation, the required environmental licenses and the investigation methods of the correlated physical context. As a result, it’s presented a flowchart of the guidelines, detailing the interaction between the environmental licensing, the geological-geotechnical studies and the phases of the pipeline’s project.

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Pós-graduação em Geologia Regional - IGCE

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Pós-graduação em Engenharia Mecânica - FEIS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Mecânica - FEIS