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.

已经研究了阿拉里佩盆地（巴西东北部）克拉托组的层状石灰岩，因为它们类似于巴西边缘盆地盐下层序的碳酸盐岩储层相。早白垩世克拉托层理岩包含一系列复杂的结构，可能在碳酸盐岩储层的孔隙度和渗透率分布中起重要作用。这项工作旨在（1）了解边界断裂带（下白垩统 Triunfo 断层）对克拉托组碳酸盐角砾岩管发育的控制，以及（2）基于现场观测限制脆性变形的时间，微观结构调查和 U-Pb 碳酸盐年代学。在正常断层和走滑断层周围都观察到角砾岩管。叠加在管道上的脆性变形以角砾岩和脉纹为特征，显示出多相矿化。我们的结果表明流体沿着预先存在的断层和管道循环，这些流体是管道中多相变形的原因。我们报告了 94.9 ± 3.8 Ma（Cenomanian 到 Turonian）和 80.2 ± 3.0 Ma（2σ）（Campanian）的碳酸盐脉矿化的两个 U-Pb 年龄，这为 Triunfo 断层带的脆性再激活提供了时间限制，在阿拉里佩盆地后裂谷期。