40 Ar/39 Ar Isotope Geochronology of Caledonian Orogenic Collapse, Southwest Norway

造山带先前增厚的地壳伸展塌陷的性质和时间是构造上的一个突出问题。到目前为止，这一建议是由于挪威西南部加里东造山带的伸展坍塌而产生的构造特征。待测年的构造特征包括：抬升的高压榴辉岩；逆行的角闪岩相变质作用；主要的千米厚的糜棱岩带，其中一些是绿片岩级的。将使用40Ar/39Ar测年方法获得高精度数据，并将能够比较不同地区的隆升年龄。与奥尔索大学当地地质学家的合作将确保在良好的结构控制下获得数据。挪威西南部著名的当地地质和极好的曝光率，加上高精度的年龄和可测试的构造模型，将极大地提高对造山带坍塌过程的理解。

An outstanding problem in tectonics is the nature and timing of extensional collapse of previously thickened crust in orogenic belts. This proposal is to date structural features attributed to the extensional collapse of the Caledonian orogen in southwest Norway. Structural features to be dated include: uplifted high- pressure eclogite rocks; retrograde, amphibolite facies meta- morphism, and; major, km-thick mylonite zones, some of which are at greenschist grade. High-precision data will be obtained using the 40Ar/39Ar dating method and will allow comparison of uplift ages among different areas. Collaboration with local geologists from the University of Olso will ensure that the data are obtained with good structural control. The combination of well-known local geology and excellent exposure in SW Norway, with high-precision ages and testable tectonic models, will significantly improve the understanding of orogenic collapse processes.