Record details

    Rhyolites from the Roztoky Intrusive Centre, České středohoří Mts.: Xenoliths or Dyke Differentiates?
Statement of responsibility
    Jaromír Ulrych, Edvín Pivec, A. Höhndorf, Kadosa Balogh, Josef Rutšek
Other titles
    Rhyolite im Roztoky Intruzionszentrum, Böhmishes Mittelgebirge: Xenolithe oder Gangförmige Differentiate?
    Balogh, Kadosa
    Bendl, Jiří
    Höhndorf, A.
    Pivec, Edvín
    Rutšek, Josef
    Ulrych, Jaromír
Source title - serial
    Chemie der Erde
    Vol. 60, no. 4
    p. 327-352
    7 obr., 4 fot., 3 tab., 3 s.bibl.
    Německé resumé
    Zkr. název ser.: Chem. d. Erde
Subject group
    chemismus hornin
    datování Rb/Sr
    datování Sm/Nd
    kenozoické vulkanity Českého masivu
Geographical name
    Beroun (Karlovy Vary)
    Dobkovice (Děčín)
    Malé Březno (Ústí nad Labem)
    Roztoky (Ústí nad Labem)
    Stříbrníky (Ústí nad Labem)
    Svádov (Ústí nad Labem)
    Tachov (Česká Lípa)
    Ústí nad Labem
    Valkeřice (Děčín)
    Vidžín (Plzeň-sever)
    Zubrnice (Ústí nad Labem)
Abstract (in english)
   Dykes or xenoliths of rhyolite were found recently within a bostonite dyke in a borehole at Malé Březno. They represent the first occurrence of the quartz-bearing volcanic rock in the České středohoří Mts. Geochemical and isotope data at the time of intrusion (87Sr/86Sr = 0.70822,143 Nd/144Nd = 0.512259, _tNd = -6.3) of the rhyolites reflect substantial crustal contamination of the magma in comparison with data on spatially associated camptonites (0.70405-0.70433; 0.512627, _tNd=+0.6), gauteites (0.70446; 0.512735, _tNd=+2.5), monzodiorites (0.70431-0.70439; 0.512703, _tNd=+2.0) or phonolite (0.70416; 0.512752, etNd=+2.9). Unusual rhyolite dykes or xenoliths were generated either by AFC process or by partial melting and trasformation of an older felsic rock - possibly originating from the Saxothuringian basement. The rhyolites occur in a spatial association with the Zortoky Intrusive Centre (RIC).
   The centre is formed by crater vent filled by trachytic breccia and hypabyssal rock series of essexite - monzodiorite - sodalite syenite (D.I. = 46-64) and linked coexisted dykes of weakly alkaline series (D.I. = 39-81) (trachybasalt) - gauteite/camptonite - bostonite/sodalite syenite porphyry - (trachyte) - (rhyolite?) and strongly alkaline series (D.I. = 39-87) (tephrite/basanite) - camptonite/monchiquite - tephriphonolite - phonolite/tinguaite/nepheline syenite porphyry were recognized. Geochemical characteristics of differentiation suite of the RIC prove its origin by fractional crystallization of mantle derived magma. Layering and almost single-step emptying of magma chamber is a presupposed mechanism of its genesis. The 87Sr/86Sr ratios of the RIC rock suite, calculated back to the time of intrusion, yielding values ranging from 0.70363 (hornblendite cumulate) to 0.70446 (gauteite) confirm its primary mantle origin without significant crustal contamination
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    13. 2. 2008
Import date
    8. 8. 2012