Paleomagnetic studies of Hercynian dyke provinces in the Western Mediterranean: Quantification and tectonic implications of crustal block rotations

岩浆通过地壳上升的路径主要受已存在和/或同岩浆发育的断层和裂缝的方向支配，因此对岩脉模式的空间分布、几何形状和方向进行仔细分析，可以重建岩脉就位期间和之后的构造应变场。此外，复杂的地质年代学方法可以非常精确地估计岩浆岩作用产物的年龄。因此，岩脉群既可以作为年龄标志，也可以作为大尺度应变标志。在地中海中部和西部，主要发育早二叠世的堤群分布在欧洲海西带南部，如加泰罗尼亚海岸山脉（CCR）、撒丁岛、科西嘉岛和意大利南部的西拉格兰德。尽管它们具有相似的辐射年龄和岩石学上的相似性，但这些岩脉的取向是不同的。上述地区岩脉格局的构造演化可能与南海西带在地中海中部的解体有关。因此，这里的堤防省可以用来获得该地区详细的构造历史的新见解。先前对撒丁岛三个堤坝省的古地磁研究表明，该岛至少分成三部分，并且这些部分围绕彼此的垂直轴旋转。正在进行的对加泰罗尼亚海岸山脉堤防省样本的古地磁测量增加了这一图景。这些测量被嵌入到一项跨学科研究中，涉及磁化率各向异性测量（AMS）和Ar/Ar测年。提交的项目旨在结合Sila Grande dyke省的古地磁数据，以便更好地了解海西造山末期地壳减薄与海西带南部张拉开始的相互作用。

The pathways of magma ascent through the crust are dominated by the orientation of pre-existing and/or syn-magmatically developed faults and fractures such that the careful analysis of the spatial distribution, geometry and orientation of dyke patterns allows the reconstruction of the tectonic strain field during and after dyke emplacement. In addition, sophisticated geochronolocial methods allow a very precise age estimation of the products of dyke magmatism. Therefore, dyke swarms can be used as both age and large-scale strain markers.In the central and western Mediterranean, dyke swarms, mainly of Early Permian age, are developed in the southern Hercynian belt of Europe, such as the Catalan Coastal Ranges (CCR), Sardinia, Corsica and Sila Grande in southern Italy. Despite their similar radiometric ages and petrological similarities, the dykes are variably oriented. The proposed tectonic evolution of the dyke patterns in in the above mentioned areas is probably related to the dismemberment of the southern Hercynian belt in the central Mediterranean. Thus, the dyke provinces here can be used for gaining new insights in the detailed tectonic history of the area.Previous paleomagnetic studies on three dyke provinces on Sardinia suggest the breakup of the island in at least three parts and rotations of those parts about vertical axes relative to each other. Ongoing paleomagnetic measurements on samples from the dyke province in the Catalan Coastal Ranges add to this picture. These measurements are embedded in an interdisciplinary study involving measurements of anisotropy of magnetic susceptibiliy (AMS) and Ar/Ar dating.The submitted project aims at incorporating paleomagnetic data from the Sila Grande dyke province in order to better understand the interactions of crustal thinning towards the end of the Hercynian orogeny and the onset of transtension in the southern Hercynian belt.