Late Cambrian/Ordovician magmatic arc type volcanism in the Southern Gemericum basement, Western Carpathians, Slovakia: U–Pb (SHRIMP) data from zircons
Late Cambrian/Ordovician magmatic arc type volcanism in the Southern Gemericum basement, Western Carpathians, Slovakia: U–Pb (SHRIMP) data from zircons
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DOI：
10.1007/s00531-009-0454-0
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发表时间：
2010-10
影响因子：
2.3
通讯作者：
A. Vozárová;Katarína Šarinová;A. Larionov;S. Presnyakov;S. Sergeev
中科院分区：
文献类型：
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作者：
A. Vozárová;Katarína Šarinová;A. Larionov;S. Presnyakov;S. Sergeev
南部成因单元（内西喀尔巴阡山脉）的低级结晶基底主要由硅质岩深水浊积岩序列和大量再沉积流纹岩/英安岩火山岩及其火山碎屑岩组成。原位U-Pb SHRIMP锆石定年应用于变质火山岩有助于规范南部杰曼结晶基底地层（Gelnica组）。本文分析了格尔尼卡岩群三个岩石地层单位的10个样品的锆石群。锆石具有明显的岩浆分带性。部分岩浆锆石含有继承的较老的核。Vlachovo组锆石的平均年龄为494 ± 1.6Ma。Bystrybow波托克组和Drnava组的平均年龄分别为465.8 ± 1.5 Ma和463.9 ± 1.7 Ma。地球化学数据与造山地球动力学背景是一致的。主要的流纹岩英安岩火山岩属于过铝质，钙碱性高钾岩浆系列。年龄数据让我们假设两个阶段的长期岩浆活动，开始于晚寒武世，并继续到中/晚奥陶世。因此，研究的格尔尼卡群晚寒武世火山岩序列反映了活动大陆边缘环境。中奥陶世第二火山活动期为裂谷期，火山活动强烈，继承了晚寒武世岩浆弧的特征。岩浆锆石的继承核有元古宙（600-760、1000 - 1400、2000 - 2700 Ma）和太古宙（3099 - 3164 Ma）年龄。
The low-grade crystalline basement of the Southern Gemeric Unit (Inner Western Carpathians) consists mainly of siliciclastic deep-water turbidite sequence associated with a huge mass of redeposited rhyolite/dacite volcanics and their volcaniclastics. In situ U–Pb SHRIMP zircon dating applied to metavolcanic rocks contributed to specification of the Southern Gemeric crystalline basement stratigraphy (the Gelnica Group). Zircon populations from ten samples of three lithostratigraphic units of the Gelnica Group rock complex have been analysed. The zircons presented significant magmatic zoning. Part of the magmatic zircons contained inherited older cores. The Vlachovo Formation gives the 494 ± 1.6 Ma zircon average age. The Bystrý potok Formation gives 465.8 ± 1.5 Ma and the Drnava Formation 463.9 ± 1.7 Ma average age. The geochemical data are compatible with an orogenic geodynamic setting. Dominant rhyolite–dacite volcanites belong to the peraluminous, calc-alkaline high-K magmatic series. The age data let us presume two phase longlasting magmatic activity, starting in the Late Cambrian and continuing to the Middle/Late Ordovician. Thus, the studied Late Cambrian volcanic sequence of the Gelnica Group reflects the active continental margin setting. The second Middle Ordovician volcanic phase documents an assumed rifting stage, accompanied by a strong volcanic activity with inherited features of the Late Cambrian magmatic arc. The inherited cores of magmatic zircons have Proterozoic (600–760, 1,000–1,400, 2,000–2,700 Ma) and Archean (3,099–3,164 Ma) ages.