The South Pyrenean triangle zone represents the southernmost front of the Pyrenees at its central portion deforming the Upper Eocene‐Miocene Ebro Basin deposits. Two main structures characterize its western termination, the Barbastro anticline and the San Román backthrust, which detached on the Barbastro Formation (and lateral equivalents), an Upper Eocene‐Lower Oligocene syntectonic evaporite‐rich formation that acted as a multidetachment unit. Northward, the south directed Pyrenean thrust unit (i.e., Gavarnie‐Sierras thrust sheet) detached along the Middle‐Upper Triassic evaporitic rocks to finally ramp up and glide along the same Upper Eocene‐Lower Oligocene multidetachment unit. A multidisciplinary approach allowed constructing a detailed structural and stratigraphic model of the study area. The workflow consisted of (1) constraining the geometry and structural architecture based on surface geology, interpretation of seismic lines (>900 km), and wells and (2) obtaining the 3‐D density distribution of the multidetachment unit using gravity stochastic inversion (more than 7,000 gravity stations and 1,500 density data). The geometry of the sole thrust of the Gavarnie‐Sierras thrust sheet was controlled by the distribution of the evaporite‐rich units of the Barbastro Fm. Weak detachments promoted thrust salient formation and thrust flat geometries. The western termination of the South Pyrenean triangle zone is defined as a westward transition from a ramp‐dominated and multiple triangle zone to a detachment‐dominated one. Its geometry, kinematics, and location were controlled by the heterogeneous lithology of the Barbastro Fm. and its basal, halite‐based detachment southern pinch‐out.

中文翻译：

---

南比利牛斯山三角带西端的结构和地球物理特征

南比利牛斯三角区代表比利牛斯山脉的最南端，在其中心部分使上新世-中新世埃布罗盆地沉积变形。它的西端有两个主要结构，即Barbastro背斜线和SanRomán反冲，它们在Barbastro地层（及其横向等价物）上分离，上部始新世-下渐新统中构造蒸发岩富集，起着多分离单元的作用。向北，向南的比利牛斯山脉冲断单元（即加瓦尔涅－塞拉山脉冲断层）沿着中上三叠统蒸发岩分离，最终沿着同一上新世—下渐新统多分离单元向上倾斜并滑行。采用多学科方法可以构建研究区域的详细结构和地层模型。工作流程包括（1）根据表面地质，对地震线（> 900 km）和油井的解释来约束几何结构和结构体系，以及（2）使用重力随机反演获得多分离单元的3D密度分布（超过7,000个重力站和1,500个密度数据）。Gavarnie-Sierras逆冲板的唯一逆冲的几何形状是由Barbastro Fm的富蒸发岩单元的分布控制的。薄弱的剥离促进了推力凸面的形成和推力平面的几何形状。南比利牛斯山脉三角带的西端定义为从坡道为主的多个三角形区域向以支配为主的区域向西过渡。它的几何形状，运动学和位置受Barbastro Fm的非均质岩性控制。