Podrobnosti záznamu

Název
    Middle/Late Cambrian intracontinental rifting in the central West Sudetes, NE Bohemian Massif (Czech Republic): geochemistry and petrogenesis of the bimodal metavolcanic rocks
Údaj o odpovědnosti
    Jaroslav Dostal, František Patočka, Christian Pin
Autor
    Dostal, Jaroslav
    Patočka, František
    Pin, Christian
Jazyk
    anglicky
Zdrojový dokument - seriál
    Geological journal
Svazek/č.
    Vol. 36
Strany
    p. 1-17
Rok
    2001
Poznámky
    2 obr., 5 diagr., 3 s.bibl.
    il.
    Zkr. název ser.: Geol. J. (Chichester).
Předmětová skupina
    chemismus hornin
    geochemie izotopická
    Gondwana
    izotopy Nd
    izotopy Sm
    kambrium
    krkonošsko-jizerské krystalinikum
    magma bimodální
    metavulkanity
    petrogeneze
    vzácné zeminy
    zóna riftová
Geografické jméno
    ČR-Čechy
    Krkonoše-Rýchory
Klíčové slovo
    Bimodal
    Bohemian
    Cambrian
    Central
    Czech
    Geochemistry
    Intracontinental
    Massif
    Metavolcanic
    Middle/Late
    NE
    Petrogenesis
    Republic
    Rifting
    Rocks
    Sudetes
    West
Abstrakt (anglicky)
   The Early Palaeozoic East Krkonoše Complex (EKC) situated in the central West Sudetes, NE Bohemia Massif, is a volcanosedimentary suite containing abundant mafic and felsic volcanics metamorphosed to greenschist facies. The trace element distribution patterns and Nd isotope signatures (E Nd 500 = +3.1 to +6.6) of the metabasites (metabasalts) indicate that they may be related to a rising mantle diapir associated with intracontinental rifting. At the early stage, limited melting of an upwelling asthenosphere produced alkali basalts and enriched tholeiites which compositionally resemble oceanic island basalts. A later stage of rifting with larger degrees of melting at shallower depths generated tholeiitic basalts with E-MORB to N-MORB characteristics.
   The values of (87Sr/86Sr)i = 0.706 and E Nd 500 = -5˝1 of porphyroids (metarhyolites) as well as the lack of rocks with intermeadiate compositions suggest that the felsic rocks were formed by a partial melting event of continental crust triggered by mantle melts. The geochemistry of the EKC bimodal metavolcanics and their association with abundant terrigenous metasediments suggest that the felsic-mafic volcanic suite was generated during intracontinental rifting. This process, widespread in Western and central Europe during the Early Palaeozoic, is evidence of large-scale fragmentation of the northern margin of the Gondwana supercontinent
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    15. 8. 2007
Datum importu
    8. 8. 2012