Análise estratigráfica em depósitos lacustres maastrichtianos da Formação Yacoraite (Bacia de Salta - Argentina): definição e rastreabilidade de sequências de alta resolução

• Ano de defesa: 2014
• Autor(a) principal: Guimarães, Saulo Pedrinha [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Geology, Stratigraphic; Geologia estratigráfica; Carbonatos; Pré-sal; Facies (Geologia); Sedimentação e depósitos; Argentina
• Link de acesso: http://hdl.handle.net/11449/131873; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/13-11-2015/000853878.pdf

The large oil discoveries of the past few years in the Brazilian pre-salt province led to necessity of studies in outcrops analogous to reservoir rocks present in that province. In this context, the Salta Basin and Yacoraite formation have a remarkable importance because of the several characteristics similar to the pre-salt sedimentary deposits. Located in northwestern Argentina, the Salta Basin evolved from an intracontinental tectonic rift context during the Cretaceous and early Paleogene, forming sub-basins that were filled by sediments of Pirgua (syn-rift), Balbuena and Santa Bárbara (both sag phase) Sub-groups. In particular, the sag development in Metán-Alemania Sub-basin during the Maastrichtian (Yacoraite Formation) allowed the deposition of carbonate rocks in a typical lake environment, where climatic factors - associated with Milankovitch cycles - played strong influence. The carbonate facies present in the studied area consist mainly of stromatolites and oolitic grainstones to packstones, which are related to periods of dry weather where the progressive decrease of lake water depth was expressive. By applying highresolution stratigraphy techniques, elementary sequences individualized were ranked into medium and low frequency sequences and correlated over tens of kilometers in the basin. Thus, high-resolution stratigraphy applied to lacustrine carbonate successions allowed a better understanding of their depositional evolution and becomes an important tool for predictability and facies mapping. It is, therefore, a methodology with applicability in the oil industry, where rocks of the same nature are reservoirs