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

EARLY- vs. LATE OROGENIC GRANITOIDS RELATIONSHIPS IN THE VARISCAN BASEMENT OF THE WESTERN CARPATHIANS

Pages: 163 - 174

Authors: MARIAN PUTIS, ALEXANDER B. KOTOV, IGOR PETRIK, SERGEI P. KORIKOVSKY, JAN MADARAS, EKATHERINA B. SALNIKOVA, SONYA Z. YAKOVLEVA, NATALYA G. BEREZHNAYA, YULIA V. PLOTKINA, VICTOR P. KOVACH, BRANISLAV LUPTAK, MICHAL MAJDAN

Abstract: The Variscan high-grade crystalline basement of the Western Carpathians contains granitic to granodioritic bodies transformed to various degrees into orthogneisses. The orthogneisses resemble the structures of the host regional-metamorphic rocks, indicating their syn-collisional evolution, predating the intrusion of the granitoids around 360–340 Ma. The Nizke Tatry Mountains orthogneiss, dated at ~381 Ma (NTJ-1 sample), emplaced during early partial melting stage deformation regime. Syn-tectonic magmatic flow and emplacement is suggested by the relics of magmatic foliations and lineations. Post-intrusion evolution comprises metamorphic/ductile medium-temperature fabrics of quartz, feldspars and micas, as well as metamorphic garnet growth. The granite-tonalite plutons emplaced between ~353 Ma (Mala Fatra Mountains) and ~343 Ma (Nizke Tatry Mountains, DUM-1 sample) during transtensive (?) deformation of the host metamorphic complex, show distinct magmatic fabric anisotropy, especially in their marginal parts, coeval with ductile fabrics of the orthogneisses. Petrologically the orthogneisses point to S-type granite or granodiorite, while the tonalites of large granitoid plutons seem to be of igneous I-type origin.

Keywords: Variscan, Western Carpathians, U-Pb zircon age, orthogneiss, granitoid, microfabric

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