Many metamorphosed basement complexes in the Alps are polymetamorphic and their origin and geological history may only be deciphered by detailed geochronology on the different members including oceanic elements like ophiolites, arc successions, and continental passive margin successions. Here we present a case study on the Lower Austroalpine Variegated Wechsel Gneiss Complex and the overlying low-grade metamorphosed Wechsel Phyllite Unit at the eastern margin of Alps. The Wechsel Gneiss Complexes are known to have been overprinted by Devonian metamorphism, and both units were affected by Late Cretaceous greenschist facies metamorphism. New U–Pb zircon ages reveal evidence for two stages of continental arc-like magmatism at 500–520 Ma and 550–570 Ma in the Variegated Wechsel Gneiss Complex. An age of ca. 510 Ma of detrital zircons in metasedimentary rocks also constrain the maximum age of metasedimentary rocks, which is younger than Middle Cambrian. The overlying Wechsel Phyllite Unit is younger than 450 Ma (Late Ordovician) and seems to have formed by denudation of the underlying Variegated Wechsel Gneiss Complex. We speculate on potential relationships of the continental arc-type magmatism of the Variegated Wechsel Gneiss Complex and potential oceanic lithosphere (Speik complex) of Prototethyan affinity, which is also preserved in the Austroalpine nappe complex. The abundant, nearly uniform 2.1 Ga- and ca. 2.5 Ma-age signature of detrital zircons in metasediments (paragneiss, quartzite) of the Variegated Wechsel Gneiss Complex calls for Lower Proterozoic continental crust in the nearby source showing the close relationship to northern Gondwana prominent in West Africa and Amazonia.

中文翻译：

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东阿尔卑斯山的韦克瑟尔片麻岩群：一个爱迪卡拉山脉至寒武纪大陆弧及其早期元古代腹地

阿尔卑斯山中许多变质的基底复合体是多变质的，它们的起源和地质历史只能由详细的年代学来解释，这些不同的成员包括海洋元素，如蛇绿岩，弧线演替和大陆被动边缘演替。在这里，我们对阿尔卑斯山东部边缘的下奥陶阿尔山杂色韦克塞尔片麻岩复合体和上覆的低品位变质韦克塞尔石柱岩单元进行了案例研究。已知Wechsel片麻岩复合体已被泥盆纪变质套印，并且两个单元均受晚白垩世绿片岩相变质的影响。新的U–Pb锆石年龄揭示了杂色Wechsel片麻岩复合体在500–520 Ma和550–570 Ma的两个阶段的大陆弧状岩浆作用的证据。大约年龄 沉积沉积岩中碎屑锆石的510 Ma也限制了沉积沉积岩的最大年龄，该年龄比中寒武纪还年轻。上层的韦氏微晶石单元小于450 Ma（晚奥陶纪），似乎是由下伏的杂色韦氏微片麻岩复合体剥蚀形成的。我们推测杂色韦克塞尔片麻岩复合体的大陆弧型岩浆作用与原始太子岩亲和力的潜在海洋岩石圈（Speik复合物）之间的潜在关系，该岩石圈也保留在奥索品隆的推覆复合物中。丰富的，几乎均匀的2.1 Ga-和ca. 2.5变质沉积物中碎屑锆石的年龄特征（paragneiss，