Podrobnosti záznamu

Název
    Origin and metamorphic evolution of Fe-Mn-rich garnetites (coticules) in the Desná Unit (Silesicum, NE Bohemian Massif)
Autor
    Buriánek, David
    Kropáč, Kamil
    Zimák, Jiří
Jazyk
    anglicky
Typ dokumentu
    článek v periodiku
Zdrojový dokument - seriál
    Chemie der Erde-Geochemistry
Svazek/č.
    Roč. 72, č. 3
Strany
    18
Rok
    2012
Výraz tezauru
    Garnetites, Coticules, Banded iron formations, Desná Unit, Silesicum, Variscan metamorphism
Klíčové slovo
    Bohemian
    Coticules
    Desná
    Evolution
    Fe-Mn-rich
    Garnetites
    Massif
    Metamorphic
    NE
    Origin
    Silesicum
    Unit
Abstrakt (anglicky)
   The Fe-Mn-rich garnetites (coticules) associated with banded iron formations occur in the Neoproterozoic metamorphic complex of the Desná Unit. Their mineral assemblage consists of almandine-spessartine garnet, quartz, magnetite, epidote and sporadically biotite, chlorite, amphibole, plagioclase, calcite, ilmenite and apatite. The mineralogical, petrological and geochemical results demonstrate that the protolith of coticules and associated BIFs was formed during periods of submarine hydrothermal activity in the Late Proterozoic by differential precipitation of Fe and Mn from low-temperature solutions. The Fe-Mn-rich precipitates mixed to a varied degree with the detritic siliciclastic material. Subsequently the protolith underwent polyphase metamorphism reaching the amphibolite facies grade during the pre-Variscan (M1) and Variscan periods. The P-T conditions assumed for the peak Variscan metamorphism (M2) are T ~540-580 °C and P ~600 MPa, the M3 is characterized by an upper pressure l
   imit 400 MPa at a maximum temperature of 600 °C and a metamorphic event M4 related to the hydration reactions which occurred during the late-stage of the Variscan orogenesis is characterized by T ~150-300 °C at P <200 MPa.
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (RIV)
Zdrojový formát
    R
Datum importu
    15. 10. 2014