Podrobnosti záznamu

    On some controversies about the geology of the West Sudetes
Údaj o odpovědnosti
    Andrzej Zelazniewicz
    Żelaźniewicz, Andrzej
Zdrojový dokument - seriál
    Zeitschrift für geologische Wissenschaften
    Vol. 24, no. 3-4
    p. 457-465
    1 obr., 2 s.bibl.
    Anglické resumé
    Zkr. název ser.: Z. geol. Wiss.
Předmětová skupina
    geologie strukturní
    orlicko-sněžnické krystalinikum
    vrásnění variské
    západosudetská oblast
Geografické jméno
    Česká republika
    Polsko - jihozápad
Klíčové slovo
Abstrakt (anglicky)
   Some numerical ages of several rocks form the West Sudetes cannot be explained so straightforward as proposed because isotopic data clearly contradict basic geological information. Eclogites in the Orlica-Snieznik Dome (OSD) together with their immediate country rocks, occur as xenoliths in a porphyritic granite, and should be considered older not younger than the latter. A Sm-Nd WR isochrone age of ca. 330-350 Ma for the OSD eclogites is therefore in conflict with an U-Pb zircon age of ca. 500 Ma for this granite.The ca. 400 Ma old quartzofeldspathic granulites in the Góry Sowie Block (GSB) have had tectonic, retrograde contacts with the host gneisses, with which they were migmatized at ca. 380 Ma. The peak of the progressive, upper amphibolite facies metamorphism of the metapelite-metagraywacke GSB complex cannot be older than the granulite event as suggested by isotopic data.
   Gabbros adjacent to the GBS shed detritus to the Upper Devonian conglomerates, therefore the Sudetic ophiolite must be older than ca. 350 Ma proposed on the basis of the Sm-Nd isotopic study. Both the OSD and GSB complexes, likewise elsewhere in the Sudetes, had undergone S-type granite magmatism and metamorphism of the Neoproterozoic-lower Ordovician sediments and then remained tectonically undisturbed in the crust under relatively high-T conditions till the Late Devonian-Early Carboniferous Hercynian events. This precludes the Caledonian, Baltica-Gondwana plate suture in the Sudet
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
Datum vložení
    20. 2. 2008
Datum importu
    8. 8. 2012