Slab factory - ocean formation and subduction in the Western Alps

阿尔卑斯山的深部结构已经被俯冲的岩石圈板片改变了，这些岩石圈板片将在AlpArray框架内用地震方法成像。在俯冲过程中，洋壳(蛇绿岩)的碎片从大洋板块上被剪切下来，成为暴露在地球表面的冲断片碰撞堆叠的一部分。它们携带着有关海洋形成、俯冲和碰撞的历史的重要信息。该项目将结合构造地质学、变质辉长岩锆石U-Pb法测年(以确定大洋扩张的年龄)以及榴辉岩和蓝片岩的Lu-Hf石榴石测年(以确定俯冲年龄)来研究西阿尔卑斯山弧内的蛇绿岩。利用这些新数据以及已有的大量数据，将重建洋盆打开和俯冲的运动学，并将对俯冲板块的性质作出预测，以支持对AlpArray记录的岩石圈结构的解释，并作为构造演化模型(SPP的活动场F，4维模拟)的输入。这些结果对于了解西阿尔卑斯山南端和过渡到亚平宁和利古里亚海特别重要，后者是AF-B(龙虾)的研究对象。我们将与AF-B项目合作，重建阿尔卑斯-亚平宁过渡的运动学演化。该项目是活动领域E(地质活动)的一部分，涉及研究主题1(岩石圈重组)和研究主题3(地壳和地幔变形)。

The deep structure of the Alps has been modified by subducted slabs of lithosphere which will be imaged by seismic methods in the framework of AlpArray. During subduction, slivers of oceanic crust (ophiolites) were sheared off from oceanic slabs and became part of the collisional stack of thrust sheets exposed at the Earth surface. These carry important information about the history of ocean formation, subduction, and collision. The project will study ophiolites in the arc of the Western Alps using a combination of structural geology, U-Pb zircon dating of metagabbros (to determine the age of oceanic spreading), and Lu-Hf garnet dating of eclogites and blueschists (to determine the age of subduction). Using these new data together with the large amount of already existing data, the kinematics of ocean basin opening and subduction will be reconstructed and predictions will be made for the nature of subducted slabs in order to support the interpretation of lithospheric structures recorded by AlpArray and serve as input for models of the tectonic evolution (Activity Field F of the SPP, 4-D MODELING). These results will be particularly important for understanding the southern end of the Western Alps and transition into the Apennines and Ligurian Sea, the subject of AF-B (LOBSTER). In collaboration with the AF-B projects, we will reconstruct the kinematic evolution of the Alps-Apennines transition.The project is part of Activity Field E (Geological activites) and deals with Research Themes 1 (Reorganizations of the lithosphere) and 3 (Deformation of the crust and mantle).