Volume 30, Issue No. 1, 2005

Rare PETROLOGICAL AND GEOCHEMICAL FEATURES OF THE MELIATA MAFIC ROCKS FROM THE SUTURED TRIASSIC OCEANIC BASIN, WESTERN CARPATHIANS

Shah Wali Faryad*, Ján Spisiak**, Péter Horváth***, Dusan Hovorka****, Ivan Dianiska° and Sándor Józsa°°

* Institute of Petrology and Structural Geology, Charles University, Albertov 6, 12843 Prague 2, Czech Republic
(Corresponding author, e-mail: faryad@natur.cuni.cz).
* Geological Institute of the Slovak Academy of Sciences, Slovak Republic.
*** Laboratory for Geochemical Research, Hungarian Academy of Sciences, H-1112, Budapest, Budaörsi út 45., Hungary.
**** Faculty of Natural Sciences, Comenius University, Slovak Republic.
° Mierova 16 Roznava, Slovak Republic.
°° Department of Petrology and Geochemistry, Eötvös Loránd University, H-1088, Budapest, Múzeum krt. 4/a, Hungary.

 

Keywords: : Ophiolite, geochemistry, metabasites, tectonic position, Meliata Unit. Western Carpathians.

ABSTRACT

Metabasites related to the Triassic Meliata oceanic basin occur along three tectonic zones in the Western Carpathians: (1) the Folkmar Zone, (2) the Roznava Zone (Meliata Unit, s.s.) and the (3) Bodva valley - Darno Hill Zone. The first two zones form the northern and southern boundary of the Paleozoic of the Gemericum (south-eastern Slovakia), respectively, and the latter is located south of the Meliata Unit, NE Hungary. All three zones contain metabasites. The serpentinites, radiolarian shales and cherts are considered to be complementary members of an ancient oceanic crust. Geochemical characteristics of metabasites from the Folkmár Zone indicate a MORB affinity. Metabasites from the Roznava Zone have affinity between MORB and within plate basalts, but metagabbros comparable with alkaline basalts are also present. The Darno Hill metabasites have MORB compositions and those from the Bodva valley are similar to the metabasites from the Roznava Zone. The geochemical and petrographic features of these metabasites suggest a continental rift volcanism, followed by spreading of the Triassic Meliata oceanic basin. During the Middle Jurassic, part of the oceanic crust and adjacent passive continental margin underwent a subduction-related blueschist facies metamorphism afterwards they were exhumed within a mélange complex of the Meliata Unit in the southern part of Gemericum.

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