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

Erbendorf-Vohenstrauí 地区（萨克森林阶 Allochthon，巴伐利亚东北部）的 Th-U-Pb 独居石岩石年代学

• 批准号: 499366296
• 负责人: Professor Dr. Bernhard Schulz
• 金额: --
• 依托单位: Institut für Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/499366296?language=en
• 关键词: Petrochronology; Th; Pb; monazite; dating

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.

波西米亚地块西缘的本多夫-沃恩施特劳斯带（ZEV）是瓦利斯坎造山带萨克森图林根带上异域的一部分。ZEV及其邻近的Moldanubian带及其变质岩和岩浆岩是大陆深钻计划（KTB）的目标区域。1995年以前，在那里进行了大量的地质岩石学和放射性年代学（U-Pb锆石，K-Ar, Ar-Ar, Rb-Sr）研究。石炭系、泥盆纪和奥陶系变质事件已在该区报道。电子探针微量分析仪（EPMA-Th-U-Pb）对云母岩中伴生矿物独居石（(LREE, Th， U, Si, Ca)PO4）的Th-U- pb定年和正射线学将在此领域得到新的应用。这种方法可以解决多变质地形中的几个热事件。通过原位分析独居石的显微结构，LA-ICP-MS和地温计分析石榴石中的Y，可以将单个样品的压力-温度（P-T）路径的不同片段与时间区段联系起来（岩石年代学）。特别是在瓦里斯坎大陆碰撞前的奥陶系变质作用的分布和特征是研究的重点。