Meta-igneous rocks of the West-Carpathian basement, Slovakia: indicators of Early Paleozoic extension and shortening events

Abstract

The paper reviews the main West-Carpathian Early Paleozoic metamorphosed originally sedimentary-magmatic complexes, dated by SHRIMP on zircons, as indicators of crustal extension and shortening events. Igneous precursors of a Layered Amphibolite Complex (LAC) -fractionated upper mantle gabbros to diorites, dated at 503 ± 4 and 492 ± 4 Ma from the North-Veporic, or 480 ± 5 and 450 ± 6 Ma from the Tatric basement are contemporaneous with subaluminous to metaluminous I-type (507 ± 4 Ma, the South-Veporic basement), peraluminous S-type (497 ± 4 Ma, the South-Veporic basement; 516 ± 7, 485 ± 6 and 462 ± 6 Ma, the North-Veporic basement; 497 ± 6, 472 ± 6 and 450 ± 6 Ma, the Tatric basement), alkaline A-type (511 ± 6 Ma, South-Veporic basement) granitic orthogneisses and calcalkaline rhyolitic (482 ± 6 Ma) and dacitic (476 ± 7 Ma) metavolcanics (Gemeric basement), indicating a magmatic immature back arc setting. The ages point to Middle/Late Cambrian, Early and Late Ordovician magmatic phases, coeval with the extension in the northern Gondwana margin. Separation of an inferred Avalonian and/or Galatian terranes distal continental ribbon corresponds with the opening of a Medio-European Basin. A 430-390 Ma dated MP/HP metamorphic event, recorded in the LAC and associated orthogneisses, occurred in the area of thinned immature back arc basin crust due to closure of the Medio-European Basin. Thus a distal Gondwana continental ribbon north of this basin could be an eastward lateral pendant of Armorica, derived from Galatian terrane. Metaophiolites of the Pernek Group (a metagabbrodolerite dated at 371 ± 4 Ma) in the Tatric basement, analogous to island-arc tholeiites and back-arc basin basalts, indicate a back-arc basin setting north of a 430-390 Ma old northward dipping subduction/collision zone, dividing the northward drifting western Galatian terrane microplate from the Gondwana margin. Some metabasites of the Gemeric basement might indicate Late Devonian to Mississippian opening of a peri-Gondwanan Paleotethyan oceanic basin: a 383 ± 3 Ma old remelted metagabbro (482 ± 9 Ma) from the Klátov gneiss-amphibolite complex, ca. 385 Ma old porphyritic metabasite of the Zlatník ophiolite complex, as well as a 350 ± 5 Ma old HP metabasite as tectonic fragment within the Rakovec Group. The closure of Devonian-Mississippian basins, accompanied by medium-pressure (the Pernek Group) to high-pressure (blueschist to eclogitic tectonic fragments in greenschist facies rocks of the Rakovec Group) metamorphism, occurred in late Carboniferous to early Permian, when Paleotethyan realm complexes accreted to a Galatian terrane microplate, the latter represented by the older and the higher-grade Tatric and Veporic basement complexes. Les roches orthodérivées du socle de la chaîne des Carpates occidentales (Slovaquie), témoins des événements extensifs et compressifs du Paléozoïque inférieurMots-clés. -Roches orthodérivées, Extension, Raccourcissement (compression), Paléozoïque inférieur, Carpates occidentales, Marge gondwanienne. Résumé. -Cet ar...

Petrology and monazite dating of the Fe-rich gneisses from Kokava (Veporic Unit, Western Carpathians, Slovakia): Devonian sediments supplied from Gondwanan-sources metamorphosed in the Variscan times

“…These data are in accord to recently published dating results of igneous, metamorphic and/or detrital zircons not only from neighbouring area but also from wide regions in the Western Carpathians (Gaab et al 2005;Kohút et al 2008;Putiš et al 2008Putiš et al , 2009. The variability of the ages (200 my absolute in-terval) and the chemical differences only emphasize their detrital origin.…”

Geochronology and petrogenesis of granitoid rocks from the Goryczkowa Unit, Tatra Mountains (Central Western Carpathians)

“…Similar ages from oscillatory zoned zircon cores, indicating Caledonian (450-460 Ma) magmatism, found recently in the High Tatra Mts (Burda et al 2013), are in accordance with findings of Late Ordovician-Early Silurian magmatic episodes in the Veporic crystalline complex (ca. 470 Ma; Janák et al 2002;Gaab et al 2003) and Tatric crystalline basement (450 and 430 Ma; Kohút et al 2008;Putiš et al 2009 …”

U–Pb zircon ages from Permian volcanic rocks and tonalite of the Northern Veporicum (Western Carpathians)

“…These rock complexes show low-temperature and medium-pressure metamorphic overprint (Korikovsky et al 1997) of the Late Cretaceous age according to "phengitic" white mica 40 Ar/ 39 Ar dating (78 ± 1.3 Ma and 84 ± 3 Ma Ma, respectively; Kohút et al 2000;Putiš et al 2009a). No remnants of Devonian lowgrade metaigneous rocks were confirmed from the northveporic area by the newer SHRIMP U-Pb zircon dating (older zircon ages 525-480 Ma and younger 480-440 Ma, Putiš et al 2008Putiš et al , 2009b.…”