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Exhumation mechanisms of middle to lower crust in the Tertiary Eastern Alps (Tauern Window)

第三纪东阿尔卑斯山中下地壳折返机制（陶恩窗）

基本信息

批准号：
32051579
负责人：
Professor Dr. Claudio Rosenberg
金额：
--
依托单位：
Arbeitsbereich Geochemie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/32051579?language=en
关键词：
Exhumation mechanisms middle lower crust

项目摘要

Middle to lower crustal rocks (up to ~ 30 km depth) of Tertiary age in the Eastern Alps are only exposed within the metamorphic dome of the Tauern Window. Past investigations concluded that this metamorphic dome was exhumed by Miocene extensional unroofing along its western and eastern boundaries. However, several observations and recent analogue models suggest that exhumation resulted from large-scale crustal folding associated with transpressive shear zones, leading to uplift and erosion. While the geometry of gneiss domes formed by extensional unroofing may be similar to that of domes formed by folding and erosion, the spatial distribution of cooling ages and cooling rates is different. Therefore, we will test different exhumation models, by applying a combined structural - geochronological investigation. Rb/Sr cooling ages on white micas and biotites from selected sites of the western lobe of the Tauern Window, combined with compiled ages of adjacent localities will enable us to construct detailed contour maps of cooling ages. In addition, we will measure cooling rates along different traverses in order to obtain a spatial distribution of the rate of cooling. These data are diagnostic for the specific mechanism of shortening and/or extension, which resulted in exhumation of deep crustal rocks. Finally, we will date synkinematic white micas from several large-scale sinistral shear zones and from the axial planes of the large-scale upright-folds of the Tauern Window. These ages will allow us to test if the upright folds were coeval with sinistral shear zones and exhumation of the Tauern dome.

东阿尔卑斯山脉第三纪的中下地壳岩石（深度约30 km）仅在陶恩窗的变质圆顶内出露。过去的调查结论是，这个变质圆顶被挖出的中新世伸展去顶沿着其西部和东部边界。然而，一些观测和最近的模拟模型表明，折返是由与逆冲剪切带有关的大规模地壳褶皱造成的，导致隆起和侵蚀。虽然由伸展去顶形成的片麻岩圆顶的几何形状可能类似于由褶皱和侵蚀形成的圆顶，但冷却年龄和冷却速率的空间分布是不同的。因此，我们将通过应用构造-年代学相结合的研究来检验不同的折返模式。从陶恩窗西叶的选定地点的白色云母和黑云母的Rb/Sr冷却年龄，结合邻近地区的汇编年龄，将使我们能够构建详细的冷却年龄等值线图。此外，我们将测量冷却率沿着不同的横向，以获得冷却率的空间分布。这些数据对缩短和/或伸展的特定机制具有诊断意义，这种机制导致了地壳深部岩石的折返。最后，我们将从几个大型左旋剪切带和陶恩窗的大型直立褶皱的轴向平面确定同运动白色云母的年代。这些年龄将使我们能够测试，如果直立褶皱是同时代的左旋剪切带和折返的陶恩圆顶。