The Iberian Central System, formed after the Alpine reactivation of the Variscan Iberian Massif, features maximum altitudes of 2500 m. It is surrounded by two foreland basins with contrasting elevation: the Duero Basin to the north, located at 750–800 m, and the Tajo Basin to the south, lying at 450–500 m. The deep crustal structure of this mountain range seems to be characterized by the existence of a moderate crustal root that provides isostatic support for its topography. New seismic data are able to constrain the geometry of this crustal root, which appears to be defined by a northward lower-crustal imbrication of the southern Central Iberian crust underneath this range. Contrarily to what was expected, this imbrication also affects the upper crust, as the existing orogen-scale mid-crustal Variscan detachment was probably assimilated during the Carboniferous crustal melting that gave rise to the Central System batholith. In addition, the lower crust might have thinned, allowing coupled deformation at both crustal levels. This implies that the reactivated upper-crustal fractures can reach lower-crustal depths, thus allowing the entire crust to sink. This new model can explain the differences in topography between the Central System foreland basins. Also, it provides further constraints on the crustal geometry of this mountain range, as it seems to be that of an asymmetric Alpine-type orogen, thus hindering the existence of buckling processes as the sole origin of the deformation. The results presented here have been achieved after autocorrelation of seismic noise along the CIMDEF (Central Iberian Massif DEFormation Mechanisms) profile. Although the resolution of the dataset features limited resolution (0.5–4 Hz, stations placed at ∼ 5 km), this methodology has allowed us to pinpoint some key structures that helped to constraint the deformation mechanisms that affected Central Iberia during the Alpine orogeny.

中文翻译：

---

地震噪声能告诉我们有关伊比利亚地块的高山复活的信息吗？伊比利亚中央系统的一个例子

伊比利亚中央系统是在瓦里斯坎伊比利亚地块的高山复活后形成的，其最大海拔为2500 m。它被两个前高低低的前陆盆地所包围：北部的杜罗盆地位于750-800 m，南部的塔霍盆地位于450-500 m。该山脉的深层地壳结构似乎以中等地壳根的存在为特征，该地壳根为其地形提供了静力支撑。新的地震数据能够约束该地壳根部的几何形状，这似乎是由该范围以下南部伊比利亚中部地壳的北下地壳自交系所定义的。与预期相反，这种胶结作用也会影响上地壳，因为现有的造山带规模的中地壳Variscan脱离可能是在石炭纪地壳融化过程中被吸收的，从而导致了中央系统的基岩。此外，下地壳可能变薄，从而在两个地壳层面都产生了耦合变形。这意味着重新活化的上地壳裂缝可以达到下地壳深度，从而使整个地壳下沉。这个新模型可以解释中央系统前陆盆地之间地形的差异。而且，它对这个山脉的地壳几何形状提供了进一步的限制，因为它似乎是不对称的高山型造山带，因此阻碍了屈曲过程作为变形的唯一根源。在地震噪声沿CIMDEF（伊比利亚中部地块变形机制）剖面自相关后，已获得此处介绍的结果。尽管数据集的分辨率具有有限的分辨率（0.5–4 Hz，大约 5公里），这种方法使我们能够确定一些关键结构，这些结构有助于限制在高山造山过程中影响伊比利亚中部的变形机制。