Alpine subduction revisited - new structural and elastic wave velocity models for improved geophysical imaging towards greater depths

在阿尔卑斯造山运动中，洋陆岩石圈都以分支洋盆、微大陆和俯冲极性反转等复杂的时空格局俯冲。这导致了地壳和地幔在深处的复杂结构。地震成像显示上地幔高速异常，在西阿尔卑斯和中阿尔卑斯明显倾向东南，在东阿尔卑斯明显倾向东北。这些构造被解释为俯冲的板块。尽管在整个阿尔卑斯山进行了精心的实地工作，并对几个现有的地震样带进行了广泛的讨论，但许多结构仍然没有得到很好的理解。尤其是深层构造在地震成像中仍然是个谜，然而更好的理解对于约束阿尔卑斯山脉的任何构造模型都是至关重要的。在这个项目中，我们将研究一套来自阿尔卑斯山西部和中部的海洋和大陆岩石，这些岩石在俯冲过程中在高压和超高压条件下变形。我们将在微观结构和织构分析以及实验室速度测量的基础上确定它们的弹性各向异性。这些数据对于地震成像的解释和使用这些数据作为输入参数的地震建模是有价值的。有了这样一个独特的构造和岩石物理数据库，(1)以前俯冲和出土的西阿尔卑斯和中阿尔卑斯的海洋和大陆单元可以根据它们在古俯冲中的位置进行表征；(2)阿尔卑斯下当前的地震速度异常可以重新解释。我们的数据对SPP 4D-MB中提出的大量项目，特别是地震学、建模和构造变质研究，也可以是工具和必要的。它符合RT1 （Reorg）的框架。岩石圈),RT3(变形。（地壳+地幔）和AF-E（地质学）。行为)。

During the Alpine orogeny, both oceanic and continental lithosphere was subducted in a complicated spatial and temporal pattern involving branching ocean basins, microcontinents, and subduction polarity reversal. This resulted in a complex structure of both crust and mantle at depth. Seismic imaging revealed high-velocity anomalies in the upper mantle, apparently dipping SE in the western and central Alps and NE in the eastern Alps. These structures have been interpreted as subducted slabs. Despite elaborate field work throughout the entire Alps and an extensive discussion of several existing seismic transects, many of the structures are still not well understood. Especially the deep structures remain enigmatic in seismic imaging, yet a better understanding is vital to constrain any tectonic model of the Alps. In this project we will study a suite of oceanic and continental rocks from the Western and Central Alps that were deformed under high and ultrahigh pressure conditions during subduction. We will determine their elastic anisotropies on the base of microstructural and textural analysis as well as by laboratory velocity measurements. This data is valuable for the interpretation of seismic imaging and for seismic modelling using the data as input parameters. With such a unique structural and petrophysical database (1) formerly subducted and exhumed oceanic and continental units of the Western and Central Alps can be characterized with respect to their position in paleo-subduction and (2) current seismic velocity anomalies under the Alps may be re-interpreted. Our data can also be instrumental and essential for a large number of projects proposed in the SPP 4D-MB, especially the seismological, the modeling and the tectonometamorphic studies. It fits in the frame of RT1 (Reorg. of Lithosphere), RT3 (Deform. of crust + mantle) and AF-E (GEOLOG. Act.).