Structural control and geochronology of Cretaceous carbonate breccia pipes, Crato Formation, Araripe Basin, NE Brazil. (October 2021)

• Record Type: Journal Article
• Authors: Celestino, Maria Alcione Lima; Miranda, Tiago Siqueira; Mariano, Gorki; Alencar, Marcio Lima; Buckman, Jim; Roberts, Nick M.W.; Barbosa, José Antonio; Neumann, Virginio H.M.L.; Braz Souza, Jorge André; Roemers-Oliveira, Eduardo
• Is Part Of: Marine and petroleum geology. Volume 132(2021)
• Publication Date: 2021-10
• Subjects: Breccia pipe -- U–Pb geochronology -- Fault reactivation -- Dolomitization -- Araripe basin; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2021.105190
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: The laminated limestones of the Crato Formation, Araripe Basin (NE of Brazil) have been investigated, as they are analogous to facies of the carbonate reservoirs of the pre-salt sequence of the Brazilian marginal basins. The Early Cretaceous Crato laminites comprise a complex range of structures that may play an important role in the porosity and permeability distribution in carbonate reservoirs. This work aims to (1) understand the control of a boundary fault zone (the Triunfo Fault, Lower Cretaceous) on the development in carbonate breccia pipes of the Crato Formation, and (2) constrain the timing of brittle deformation, based on field observations, microstructural investigation and U–Pb carbonate geochronology. The breccia pipes are observed surrounding both normal and strike-slip faults. The brittle deformation superimposed on the pipes is characterized by brecciation and veining that show multiples phases of mineralization. Our results propose the circulation of fluid along the pre-existing faults and pipes, these fluids are responsible for polyphasic deformation in the pipes. We report two U–Pb ages from carbonate-vein mineralization of 94.9 ± 3.8 Ma (Cenomanian to Turonian) and 80.2 ± 3.0 Ma (2σ) (Campanian), which provide time constraints on the brittle reactivations of the Triunfo Fault Zone, during the post-rift phase of the Araripe Basin. Highlights: Polyphase formation of breccia pipes in Aptian carbonates strongly controlled by a fault zone of the Araripe Basin. Two reactivation episodes of the Fault Triunfo zone dated at 94.9 ± 3.8 Ma (Cenomanian to Turonian) and 80.2 ± 3 Ma (Campanian). Vein fills register fluids of different chemical composition during the post-rift phase of the Araripe Basin. Multiple fluid circulation events through pre-existing faults and pipes are responsible by deformations in the breccia pipes.