EVENTOS TECTÔNICOS RECORRENTES IMPRESSOS NO ARCABOUÇO ESTRATIGRÁFICO DO GRUPO ITARARÉ NA REGIÃO DE VILA VELHA, ESTADO DO PARANÁ

This paper describes the tectonic control on the depositional and post depositional evolution of the lateCarboniferous glacial Itararé Group in the eastern flank of the Paraná Basin, southeast Paraná State. Emphasiswas given on the structural and stratigraphic organization of the Vila Velha sandstone, an outcrop analogue tosubsurface reservoirs in the Ponta Grossa – Itararé petroleum system. The study was based on satelliteimage and digital elevation model analysis, aerial photograph interpretations (1:25.000 and 1:10.000), detailedvertical stratigraphic profiles, descriptive, kinematic and dynamic analysis of deformational structures andgeological mapping. The results suggest a series of tectonic events related to Phanerozoic evolution of theSouth American Platform that can be observed in the Vila Velha sandstone. In the studied area, the ItararéGroup was deposited unconformably on a Devonian basement affected by tectonism triggered by the Eo-Hercynian orogeny during Late Devonian to Late Carboniferous times. Distribution of the lowermost glacialfacies of the Itararé Group and its spatial relationship with major tectonic features suggest tectonic controlduring the first depositional phase in the Late Carboniferous. The second depositional phase was marked bydeposition in marine, glaciomarine and shoreline environments due to deglaciation. This episode produceda 100 m thick and highly heterogeneous sand-rich succession (Vila Velha sandstone). Structural analysisshowed that these sandstones were affected by at least three brittle deformational events, which appear asfracture systems and fault zones visible on remote sensing images and direct outcrop observation. The firstdeformation event generated north-northeast fracturing and northeast sinistral strike-slip faulting, exemplifiedby the Fortaleza Fault, probably related to Fini-Hercynian intraplate stress propagation induced by the PermianLa Ventana-Cabo orogeny recorded in the Sierras Australes of Buenos Aires. The second event is recorded bynorthwest fractures and normal faults clearly related to the Early Cretaceous extensional and magmatic eventdue to the South-Atlantic rifting. This event produced the uplift of the Ponta Grossa Arch and the developmentof regional northwest structures that cross almost the entire basin, like the Rio Alonzo lineament. Patterns ofsedimentation and superimposed tectonic deformations observed in the Vila Velha sandstone provide astratigraphic/structural anisotropy that control flow units and fluid circulation within the porous media.O presente trabalho avalia o controle tectônico na deposição e deformação do intervalo basal doGrupo Itararé no sudeste do Estado do Paraná e sua influência na anisotropia de reservatórios análogos. Apartir da análise estrutural do arenito Vila Velha, a observação das relações espaciais entre a conformaçãodos estratos e as estruturas descritas e o mapeamento geológico de detalhe, propõe-se um modelo deevolução tectono-sedimentar para a área. O Grupo Itararé foi depositado em contexto glacial, glácio-marinhoe costeiro, tendo sido afetado por vários eventos tectônicos que influenciaram a sedimentação e deformarama seção sedimentar. A descrição do arcabouço estrutural/estratigráfico sugere uma história tectônica complexa,do Carbonífero ao Eocretáceo, com estruturas tectonicamente ativas durante a deposição e a suareativação em eventos tectônicos posteriores. A natureza da sedimentação e a deformação tectônicasuperimposta em múltiplos eventos imprimiram no arenito intensa anisotropia, com diferentes escalas deheterogeneidades estruturais e estratigráficas que limitam unidades de fluxo e controlam a circulação defluidos no meio poroso