Petrochronology with Th-U-Pb monazite dating in the Zone of Erbendorf-Vohenstrauß (Saxothuringian Allochthon, NE-Bavaria)

位于波希米亚地块西缘的埃尔本多夫-弗亨斯特劳区（ZEV）是华力西造山带Saxothuringian区上外来域的一部分。ZEV和邻近的Moldanubian带及其变质岩和岩浆岩是大陆深部钻探计划（KTB）的目标区域。在1995年之前，已在那里进行了强烈的地质岩石学和放射性年代学（U-Pb锆石，K-Ar，Ar-Ar，Rb-Sr）。该区曾有石炭纪、泥盆纪和奥陶纪变质事件的报道。电子探针微量分析仪（EPMA-Th-U-Pb）测定云母片岩和正片麻岩中的副矿物独居石（（LREE，Th，U，Si，Ca）PO_4）的Th-U-Pb年龄，将在该地区得到新的应用。这种方法可以解决几个热事件在多变质地形。通过独居石的显微结构原位分析、石榴石中钇的LA-ICP-MS分析和地质温压法，可以将压力-温度（P-T）路径的不同段与单个样品的时间段联系起来（岩石年代学）。特别是华力西碰撞前奥陶纪变质作用的分布和特征是研究的重点。

The Zone of Erbendorf-Vohenstrauß (ZEV) at the western margin of the Bohemian Massif is part of the Upper Allochthonous Domain in the Saxothuringian Zone of the Variscan Orogen. The ZEV and the adjacent Moldanubian Zone with their metamorphic and magmatic rocks were the target region of the Continental Deep Drilling Program (KTB). Intense geological-petrological and radiochronological (U-Pb zircon, K-Ar, Ar-Ar, Rb-Sr) have been performed there previous to 1995. Carboniferous, Devonian and Ordovician metamorphic events have been reported from the region. The Th-U-Pb dating of the accessory mineral monazite ((LREE, Th, U, Si, Ca)PO4) by electron probe microanalyser (EPMA-Th-U-Pb) in micaschists and orthogneisses now will be newly applied there. This method allows to resolve several thermal events in polymetamorphic terrains. By the in situ analysis of monazite in microstructures, analysis of Y in garnet by LA-ICP-MS and geothermobarometry, distinct segments of the pressure-temperature (P-T) paths can be related to time sections in single samples (Petrochronology). Particularly the distribution and character of the Ordovician metamorphism previous to the Variscan continental collision is a target of the investigation.