caa a22 4500 445389923 CHVBK 20180317143043.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s00710-011-0176-4 doi (NATIONALLICENCE)springer-10.1007/s00710-011-0176-4 Pre-Variscan evolution of the Western Tatra Mountains: new insights from U-Pb zircon dating [Elektronische Daten] [Jolanta Burda, Urs Klötzli] In situ LA-MC-ICP-MS U-Pb zircon geochronology combined with cathodoluminescence imaging were carried out to determine protolith and metamorphic ages of orthogneisses from the Western Tatra Mountains (Central Western Carpathians). The metamorphic complex is subdivided into two units (the Lower Unit and the Upper Unit). Orthogneisses of the Lower Unit are mostly banded, fine- to medium-grained rocks while in the Upper Unit varieties with augen structures predominate. Orthogneisses show a dynamically recrystallised mineral assemblage of Qz + Pl + Bt ± Grt with accessory zircon and apatite. They are peraluminous (ASI = 1.20-1.27) and interpreted to belong to a high-K calc-alkaline suite of a VAG-type tectonic setting. LA-MC-ICP-MS U-Pb zircon data from samples from both units, from crystals with oscillatory zoning and Th/U > 0.1, yield similar concordia ages of ca. 534Ma. This is interpreted to reflect the magmatic crystallization age of igneous precursors. These oldest meta-magmatics so far dated in the Western Tatra Mountains could be linked to the fragmentation of the northern margin of Gondwana. In zircons from a gneiss from the Upper Unit, cores with well-developed oscillatory zoning are surrounded by weakly luminescent, low contrast rims (Th/U < 0.1). These yield a concordia age of ca. 387Ma corresponding to a subsequent, Eo-Variscan, high-grade metamorphic event, connected with the formation of crustal-scale nappe structures and collision-related magmatism. The Author(s), 2011 Burda Jolanta Faculty of Earth Sciences, University of Silesia, Sosnowiec, Poland aut Klötzli Urs Department of Lithospheric Research, University of Vienna, Vienna, Austria aut Mineralogy and Petrology Springer Vienna 102/1-4(2011-10-01), 99-115 0930-0708 102:1-4<99 2011 102 710 https://doi.org/10.1007/s00710-011-0176-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-011-0176-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Burda Jolanta Faculty of Earth Sciences, University of Silesia, Sosnowiec, Poland aut NATIONALLICENCE 700 1- Klötzli Urs Department of Lithospheric Research, University of Vienna, Vienna, Austria aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer Vienna 102/1-4(2011-10-01), 99-115 0930-0708 102:1-4<99 2011 102 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer