The Barreirinhas pull-apart system encompasses marginal basins in divergent and transform margin segments in the central sector of the Brazilian Equatorial Margin and its African conjugate counterpart. This ancient pull-apart system evolved through transtensional strike-slip motion within a highly heterogeneous crystalline basement affected by multiple rift phases. The geometry and development of pull-apart structural elements during the final rifting phase before continental breakup and the mechanisms and extent to which they were influenced by preexisting crustal heterogeneities are comprehensively addressed using an extensive database of potential field (magnetic and gravity) and 2D seismic reflection data. We also assess the lithospheric thermomechanical conditions and their influence on transtensional extension throughout Curie Point Depth, Heat Flow, and Moho depth, derived from potential field data and published seismological models. Plate reconstruction of Brazilian and African equatorial margins based on gravity patterns and comparison with sandbox analog models allow a 3D synoptic model to reveal the Barreirinhas pull-apart system evolution during the Equatorial Atlantic opening. During the rift phase I, the location of major grabens was controlled by favorably oriented Neoproterozoic shear zones, while the cooler, stronger, and thicker crust beneath cratonic areas formed the western barrier to strike-slip rift activity during rift phase II. This same geological domain anchored the onset of the pull-apart system in the last rift phase III, whose principal displacement zones developed along the extensive oceanic fracture zones linked by sigmoidal fault systems. Toward the end of the rift phase, a large asymmetric lozangle to a lazy--shaped, pull-apart basin developed above low overlapping ∼90°, releasing stepover in oblique transtensional strike-slip motion.

中文翻译：

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巴西赤道边缘张拉Barreirinhas拉分系统的演化及其与非洲共轭对应系统的相关性


巴雷里尼亚斯拉分系统包括巴西赤道边缘及其非洲共轭对应部分中央部分的发散和转换边缘部分的边缘盆地。这种古老的拉分系统是通过受多个裂谷阶段影响的高度异质晶体基底内的张拉走滑运动演化而来的。使用广泛的位场（磁场和重力）和二维地震数据库，全面解决了大陆分裂前最后裂谷阶段拉分结构元素的几何形状和发展，以及它们受先前存在的地壳不均匀性影响的机制和程度。反射数据。我们还评估了岩石圈热机械条件及其对居里点深度、热流和莫霍面深度的转张延伸的影响，这些影响来自位场数据和已发布的地震模型。基于重力模式对巴西和非洲赤道边缘进行板块重建并与沙箱模拟模型进行比较，使 3D 天气模型能够揭示赤道大西洋开口期间巴雷里尼亚斯拉分系统的演化。在裂谷第一阶段，主要地堑的位置受有利定向的新元古代剪切带控制，而克拉通区域下方较冷、较坚固、较厚的地壳在裂谷第二阶段形成了走滑裂谷活动的西部屏障。同样的地质区域锚定了最后一个裂谷第三阶段拉离系统的开始，其主要位移区沿着由乙状断层系统连接的广泛海洋断裂带发育。 在裂谷期末期，在低重叠～90°以上形成了一个大的不对称菱形，形成了惰性形状的拉裂盆地，释放了斜向拉张走滑运动中的步距。