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

ALPINE LOW-GRADE METAMORPHISM OF THE PERMIAN-TRIASSIC SEDIMENTARY ROCKS FROM THE VEPORIC SUPERUNIT, WESTERN CARPATHIANS: PHYLLOSILICATE COMPOSITION AND ”CRYSTALLINITY” DATA

Pages: 367 - 375

Authors: BRANISLAV LUPTAK, MARIAN JANAK, DUSAN PLASIENKA, SUSANNE TH. SCHMIDT

Abstract: Alpine low-grade metamorphism related to Cretaceous orogeny has been investigated in the metasediments of the Permian-Triassic cover in the Veporic Superunit, Western Carpathians. Metaclastic rocks and marbles show metamorphic grade of upper anchizonal to epizonal (greenschist facies) conditions according to the illite “crystallinity” measurements. The chlorite thermometry of Cathelineau (1988) and Jowett (1991) yields a temperature of ca. 310–330 °C in the northern part and ca. 335–380 °C in the central and eastern parts of the Veporic Superunit. A pressure of ca. 4–4.5 kbar has been obtained from the white mica, K-feldspar and biotite-bearing rocks, supposing a temperature of ca. 380 °C. The new results suggest higher temperature and lower pressure of the Alpine low-grade metamorphism than the previous estimates. The P-T conditions of the Alpine low-grade metamorphism in the Veporic Superunit are in good agreement with the observed deformational microtextures.

Keywords: Alpine metamorphism, Western Carpathians, Veporic Superunit, Permian-Triassic cover, geothermobarometry, crystallinity index

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