2024-10-082024-10-082022-08-22VASCONCELOS, Elizangela de Jesus. Indicadores geoquímicos aplicados na caracterização de oxirredução durante deposição de folhelhos negros do Membro Assistência, Formação Irati da Bacia do Paraná. Orientador: Candido Augusto Veloso Moura. Coorientador: Afonso César Rodrigues Nogueira. 2022. 70 f. Trabalho de Curso (Bacharelado em Geologia) - Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2022. Disponível em:https://bdm.ufpa.br/jspui/handle/prefix/7310. Acesso em:.https://bdm.ufpa.br/jspui/handle/prefix/7310The Irati Formation, deposited in a restricted marine environment during the Permian, is formed by the Taquaral and Assistência members that constitute the carbonate and siliciclastic depositional systems of the unit. It represents one of the largest reserves of bituminous shales in the Paraná Basin, which generate gas and fuel oil as byproducts. Records of anoxia have been increasingly observed amidst the deposits of the Assistencia Member, leading to questions about the lateral variation and extent of anoxic conditions in the basin in the Permian. Black shales have abundant organic matter in their contents and their depositional conditions are anaerobic. They originate in both anoxic and euxinic environments, and geochemical indicators are used to recognize these conditions. The present work uses geochemical parameters to investigate the redox conditions of the Irati Formation in the north region of the basin (Goiás). This geochemical information is compared with those available for of the south region (Rio Grande do Sul), to verify possible variations of the anoxia/euxinia conditions in the basin extension. Total Organic Carbon (TOC), Degree of Pyritization (DOP), and elements sensitive to redox, such as U, V, Mo, Cr, Co, Ni, Cu, Zn and Cd, and Cu/Mo and Mo/COT ratios are used as parameters. In Perolândia (Goiás) deposits of the Member Assistance crop out. Black shales, which occur intercalated with carbonate rocks, were collected for geochemical studies. Trace and major element analyses of these mudstone were carried out in a commercial laboratory. The Enrichment Factor (EF), in general, shows that the sediments of the Assistencia Member in the northern part of the basin are more enriched in trace elements when compared with the deposits of the southern. The DOP and FeT/Al values indicate that there were pulses of deposition under suboxic conditions and, also in inhospitable conditions (reducing environment) in both regions. The increasing organic flux can be considered a conditioning factor for the reducing environment suggested by the Cu and Cu/Mo relation. Mo concentrations and the Mo/COT ratio allowed to identify sulfidic restricted conditions. The geochemical information available for the Permian shales of the Assistencia Member, from the northern and southern portions of the Paraná Basin, show that they are heterogeneous. However, the black shales show strong evidence of anoxia during their deposition, and records of suboxic conditions.Acesso AbertoFolhelhos negrosFormação IratiPermianoBacia do ParanáBlack shalesIrati FormationPermianParaná BasinCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIATrabalho de Curso - Graduação - Monografia