U-Pb and Ar-Ar dating of minerals from metamorphic and syn-orogenic sedimentary rocks as a key to understanding architecture and evolution of collisional orogens

中欧华力西期内生岩是基底单元、推覆遗迹和同造山沉积的拼贴体，具有不同的成因，表现出广泛的年龄和变质变形程度。一个突出的例子是ErzgeBirge和Saxon麻粒岩地块的陆壳岩石，它们分别在超高压(UHP)和超高温(UHT)条件下于早石炭世变形和变质。这些岩石最初从地幔深处近等温折返的速度非常快。上地壳麻粒岩侵位引起接触变质光环，这可能是世界上独有的。在晚期结晶时代的花岗岩侵入之前，高级变质作用和大变形已经结束。相反，上覆的Frankenberg Klippe和毗邻的Lusatian地块没有经历这种变质作用。海尼臣盆地局部碎屑沉积与高级别基底单元的变质和折返同时代，记录了折返、冷却和剥蚀的历史。我们的主要目的是利用40Ar/39Ar年代学和U-Pb年代学相结合的方法，研究华力西东部内陆带UHP/HP和UHT单元的折返剥蚀历史。选定的基底单元将作为对比目标，以探测它们之间的年龄不连续性，限制重结晶和折返年龄，并用于证明-Nance和Ar遗传研究。此外，通过研究海南巴新沉积在性质和来源上如何随时间变化，我们将能够确定折返速率，以及超高压/高压和超高温单元的暴露和初始侵蚀的时间。关键词：大陆碰撞造山作用、折返作用、同造山沉积、Ar-Ar和U-Pb地质年代学、欧洲华力西岩带

The Variscan internides in central Europe are a collage of basement units, nappe relics, and syn-orogenic deposits that have varying origins and show a wide range in age and degree of metamor-phism and deformation. An outstanding example are continental crust rocks from the Erzgebirge and the Saxon Granulite Massif, which were deformed and metamorphosed in the Early Carboniferous un-der, respectively, ultrahigh-pressure (UHP) and ultrahigh-temperature (UHT) conditions. The initial near-isothermal exhumation of these rocks from mantle depths was very fast. Probably unique in the world, granulite emplacement in the upper crust caused a contact metamorphic aureole. High-grade metamorphism and major deformation had ended before granites with Late Viséan crystallization ages intruded. In contrast, the overlying Frankenberg Klippe and the contiguous Lusatian Block escaped this metamorphism. Locally-derived clastic sediments of the Hainichen Basin are coeval with meta-morphism and exhumation of the high-grade basement units, thus recording the history of exhumation, cooling, and erosion. Our primary aim is to investigate the exhumation and denudation history of the UHP/HP and UHT units in the eastern Variscan internides by using a combination of 40Ar/39Ar and U-Pb geochronology. Selected basement units will be targeted for correlation purposes in order to detect age discontinuities between them, to constrain recrystallization and exhumation ages, and for prove-nance and argon inheritance studies. In addition, by studying how the sediments of the Hainichen Ba-sin change over time in character and origin we will be able to establish exhumation rates, and the time of exposure and initial erosion of the UHP/HP and UHT units. Key words: continental collision orogeny, exhumation, syn-orogenic deposition, Ar-Ar and U-Pb geo-chronology, European Variscan Belt