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

METAMORPHOSED CARBONATES OF KRKONOSE MOUNTAINS AND PALEOZOIC EVOLUTION OF SUDETIC TERRANES (NE BOHEMIA, CZECH REPUBLIC)

Pages: 281 - 297

Authors: JINDRICH HLADIL, FRANTISEK PATOCKA, VACLAV KACHLIK, ROSTISLAV MELICHAR, MARTIN HUBACIK

Abstract: The metamorphosed carbonate bodies structurally embedded in the East and South Krkonose Complexes (ESKC — N Bohemian Massif, Krkonose Mountains, Czech Republic) have principally two types of sedimentary precursors. The first precursor corresponds to Early Cambrian dolomitized oolites and microbialites (Dolni Alberice) and provides practically the same fauna and geochemical features on residues as observed in Lusatia (Doberlug-Torgau Syncline). The Cadomian calc-alkaline meta-igneous rock sources, geochemically observed on this Early Cambrian, were also found in the Early Devonian of the Barrandian. The second precursor consists of open-sea calcitic wackestones/packstones and dolomitized packstones/grainstones (Ponikla and Horni Lanov, part) and yields fossil remnants, which are widely comparable with N Gondwanan carbonate sediments of the Bohemian type. The Middle–Late Devonian sedimentary continuation in the ESKC was likely absent (or restricted), and this was preceded by increased geochemical variation of insoluble residues in the marble precursors. Successively diversified compositions of trapped weathering products (regional to inter-regional background sediment, close to Post-Archean Average Australian Sedimentary distribution in REE, with a significant proportion of atmospheric depositions) suggest, that area precursors of the ESKC, Lusatia, Barrandian and Polish Central Sudetes were well separated and expanded to a great extent. The residues from carbonate rocks of the Sudetes correspond to a complex paleotectonic evolution — from Cambrian intracontinental rifting to Devonian arcs. However, there is a trend toward the East and with time toward the Middle Devonian, that Sudetic carbonatic residues indicate a variety of sources posing a wide spectrum of tectonic setting types.

Keywords: Early Paleozoic, Gondwana, Bohemian Massif, Sudetes, recrystallization, rare earth elements, archaeocyaths, trilobites, dacryoconarids, oolites, microbialites

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