International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

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Granitic pegmatites of the beryl–columbite subtype in the Tatric Superunit, Western Carpathians, Slovakia: Variscan age determination by in-situ LA–ICP–MS U–Pb dating of columbite-group minerals

Published: Jun 2024

Pages: 157 - 169

DOI: https://doi.org/10.31577/GeolCarp.2024.09

Authors: PAVEL UHER, IGOR BROSKA, STOYAN GEORGIEV, SERGII KURYLO, MARTIN ŠTEVKO

Abstract: Accessory columbite-(Fe) to tantalite-(Fe) from three granitic pegmatites of the Tatric Superunit (Bratislava Massif of the Malé Karpaty Mts., Bojná Massif of the Považský Inovec Mts. and Suchý Massif of the Strážovské Mts.) was used for dating by the in-situ LA–ICP–MS U–Pb method. The columbite–tantalite crystals were sampled from the most fractionated pegmatite dykes of the beryl–columbite subtype situated in the pre-Alpine, Paleozoic crystalline basement of the Tatric Superunit, Western Carpathians (western and central Slovakia). The obtained columbite–tantalite Concordia ages are as follows: 354.5 ± 4.5 Ma (Jezuitské Lesy pegmatite, the Bratislava granite Massif), 360 ± 5.0 Ma (Moravany nad Váhom, Striebornica Ridge pegmatite, the Bojná Massif), and 352 ± 8.5 Ma (Liešťany, Bystrý Hill pegmatite, the Suchý Massif). The columbite–tantalite ages show Mid-Variscan formation of rare-element pegmatites from the Devonian/Carboniferous boundary to Tournaisian stage, which is coeval with the emplacement of cogenetic granites during the main phase of Variscan intracontinental subduction and collision. The obtained columbite–tantalite age interval of rare-element granitic pegmatites of the Tatric Superunit (~360 to 350 Ma) is generally older than the ages of Be- and Li-rich rare-element pegmatites of the Moldanubian Superunit in the Bohemian Massif (~340 to 320 Ma). The rare-element granitic pegmatites of the Austroalpine Superunit (Eastern Alps) are significantly younger (~290 to 240 Ma) because they were formed in an extension regime during the Permian to Early Triassic post-Variscan orogenic collapse.

Keywords: columbite, tantalite, granitic pegmatite, LA–ICP–MS U–Pb dating, Variscan orogeny, Tatric Superunit, Western Carpathians

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