Análise de proveniência sedimentar da Formação Pirambóia na porção central do estado de São Paulo: abordagem source-to-sink e caracterização do reservatório

• Autor(a) principal: Christofoletti, Beatriz
• Data de Publicação: 2022
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/217268
• topic: Pirambóia Formation; Sedimentary provenance; Geochemistry of detrital rutile; Reservoir rock; Formação Pirambóia; Proveniência sedimentar; Geoquímica de rutilo detrítico; Rocha reservatório

The study of sedimentary provenance is widely used in basin analysis and aims to reconstruct the existing relationships between source areas and sedimentary basins. This approach is mainly based on classical sedimentological methods, such as paleocurrents and sedimentary facies. However, in recent years, the sedimentary provenance has acquired a multidisciplinary subject, involving the mineral studies, the petrological characteristics of the source rocks, the diagenetic conditions, and the application of geochemical methods, especially analysis of detrital minerals, trace elements and isotopes. In this context, this study innovatively priorized the use of rutile geochemistry to determine the mafic or felsic nature of the probable source areas of the Piramboia Formation (Paraná Basin) in the central portion of the State of São Paulo, as well as to determine the rutile crystallization temperature in the source rock using the Zr-in-Rt geothermometer. Due to the controversial nature of the stratigraphic relationships of the Pirambóia Formation with the vertically contiguous formations (Corumbataí and Botucatu formations), the scarce paleontological content, and doubts about its depositional age of the unit, the study of sedimentary provenance becomes quite relevant, given that allows difining similarities and differences in the source area and depositional polarity between different lithostratigraphic units. Likewise, the analysis of provenance makes it possible to define the mineralogical composition and origin of the sands that constitute the reservoir rocks of the Irati Pirambóia Petroleum Systemm, considered the pioneer in onshore hydrocarbon research in the country. As a result of the analyzes carried out, the trace elements in rutile indicates mostly source areas of felsic character, crystallized between 525 - 750°C (amphibolite facies). These results with the paleocurrent data from the literature, indicated a source area for these rocks located to the NE, comprising, therefore, the Ribeira and Brasília belts as the main sources that provided sediments for the Pirambóia Formation. The rutiles that present mafic character was interpreted as coming from mafic-ultramafic complexes also associated with these regional structures. Due to the proximity to the Paraná Basin at the time of deposition, the possibility of second source areas located in the western portion of the Angolan Shield on the African continent can also be considered.