High- and ultrahigh-pressure rock exhumation and tectonic structure of the southeastern Austroalpine crust

南阿尔卑斯山地壳高压和超高压岩石折返及构造结构

• 批准号: 442590636
• 负责人: Professor Dr. Nikolaus Froitzheim
• 金额: --
• 依托单位: Institut für Geowissenschaften und Geographie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/442590636?language=en
• 关键词: ultrahigh; pressure; rock; exhumation; tectonic

The Austroalpine Superunit is a pile of allochthonous thrust sheets in the Eastern Alps, forming the upper plate during Paleogene southward subduction of the Penninic ocean and the following collision with Europe. Earlier, at 100 to 90 Ma, parts of the Austroalpine were affected by subduction-related metamorphism up to ultrahigh pressures (e.g., diamond-bearing gneisses). This metamorphism affected thinned continental crust in a southeast-dipping subduction zone. The exhumation of these rocks (~90 to 80 Ma) is not yet understood in terms of kinematics and mechanics but of crucial importance for the tectonic evolution of the Eastern Alps, their crustal and lithospheric geometry, and their relationships with the Carpathians, Dinarides, and Pannonian Basin.We will study exhumation of the Saualpe-Koralpe-Pohorje Complex (SKPC), the most deeply subducted part of the Austroalpine, combining outcrop-scale structural and strain analysis, as well as microstructural and texture analysis using electron-backscatter diffraction (EBSD) and time-of-flight neutron diffraction. Thereby we will investigate the deformation path and the geometry and distribution of strain accumulated during exhumation and test the hypothesis that the SKPC was extruded from the subduction zone by localized, non-cylindrical flow. We will reconstruct the geometry of the SKPC and stepwise retrodeform its exhumation. We will incorporate our results into a 3D geometric model of the Eastern Alps. Based on these results we will interpret the deep crustal and lithospheric structure in the Eastern part of the Alps and the transition into the Carpathians and Dinarides, in close collaboration with other projects within the SPP that deal with the metamorphic evolution of the SKPC and the deep lithospheric structure of the Eastern Alps.

奥阿尔卑斯超单元是东阿尔卑斯山的一堆异地逆冲岩席，形成于早第三纪宾尼克洋向南俯冲和随后与欧洲碰撞期间的上板块。早在100至90 Ma，部分Austroalpine受到俯冲相关变质作用的影响，最高可达1000 MPa（例如，含金刚石片麻岩）。这种变质作用影响了东南倾斜俯冲带的薄化大陆地壳。这些岩石的挖掘（~90至80 Ma）尚未在运动学和力学方面得到理解，但对于东阿尔卑斯山脉的构造演化，其地壳和岩石圈几何形状及其与喀尔巴阡山脉，Dinarides和Pannonian盆地的关系至关重要。我们将研究Saualpe-Koralpe-Pohorje杂岩（SKPC）的折返，该杂岩是Austroalpine俯冲最深的部分，结合露头尺度的结构和应变分析，以及使用电子背散射衍射（EBSD）和飞行时间中子衍射的显微结构和纹理分析。因此，我们将调查的变形路径和几何形状和分布的应变在折返过程中积累和测试的假设，即SKPC被挤出的俯冲带由本地化，非圆柱形流。我们将重建SKPC的几何形状，并逐步逆变形其折返。我们将把我们的结果纳入到一个东阿尔卑斯山的三维几何模型。根据这些结果，我们将解释深层地壳和岩石圈结构在东部的阿尔卑斯山和过渡到喀尔巴阡山脉和Dinarides，在SPP内处理的SKPC和东部阿尔卑斯山的深层岩石圈结构的变质演化的其他项目密切合作。