Record details

Title
    Petrogenesis of contrasting granitoid plutons in western Bohemia (Czech Republic)
Statement of responsibility
    W. Siebel, Karel Breiter, I. Wendt, A. Höhndorf, F. Henjes-Kunst, Miloš René
Other titles
    Petrogeneze kontrastierender Granitplutone in Westböhmen (Tschechien)
Author
    Breiter, Karel, 1956-
    Henjes-Kunst, F.
    Höhndorf, A.
    René, Miloš
    Siebel, Wolfgang
    Wendt, I.
Language
    anglicky
Source title - serial
    Mineralogy and petrology
Vol./nr.
    Vol. 65, no. 3-4
Pages
    p. 207-235
Year
    1999
Notes
    10 obr., 4 tab., 4 s.bibl.
    Německé resumé
    Zkr. název ser.: Mineral. and Petrology
Subject group
    bohemikum
    chemismus hornin
    geochronologie
    granitoidy
    moldanubikum
    petrogeneze
    prvky stopové
    původ korový
    tavení parciální
    vrásnění variské
    západočeský pluton
    zóna střižná
Geographical name
    Babylon (Domažlice)
    Bor (Tachov)
    ČR-Čechy
    Rozvadov (Tachov)
    SRN-Bayern
Keyword
    Bohemia
    Contrasting
    Czech
    Granitoid
    Petrogenesis
    Plutons
    Republic
    Western
Abstract (in english)
   Late-Variscan granitoid plutons in western Bohemia (Bor, Waidhaus-Rozvadov) have distinct petrographic, geochemical and isotopic features that suggest different magmatic evolutions. The Bor pluton comprises a suite of metaluminous tonalites and quartz diorites (Bor I), weakly peraluminous (monzo-) granites and granodiorites (Bor II) and medium-aluminous, late vein-forming leucomonzogranites (Bor III). The Waidhaus-Rozvadov pluton is strongly peraluminous, comprising a cordierite-biotite granitoid (CBG), the Rozvadov granite (ROG), the Bärnau granite (BÄG) and the subordinate, higly evolved Kreuzstein (Křížový kámen) granite (KG). Geochemical parameters and initial 87Sr/86Sr ratios straddle the boundary between I- and S-type granites in the Bor pluton and are characteristic of purely S-type granites in the Waidhaus-Rozvadov pluton. The Bor II granitoids have been dated by the Rb-Sr whole-rock method at 34 17 Ma (ISr=0.70724 0.00060).
   K-Ar biotite and muscovite ages of all units of the Bor pluton are mainly in the range 321-315 Ma. The K-Ar mineral ages are in good agreement with recently published U-Pb zircon data of these rocks. The different units of the Waidhaus-Rozvadov pluton have yielded less well-constrained Rb-Sr whole-rock ages, ranging from 313 to 300 Ma. However, the intrusion sequence is constrained by K-Ar muscovite ages (312-302 Ma), which define a systematic decrease towards the chemically more evolved granite types. Taken as a whole, it seems likely that the new radiometric ages characterize two temporally distinct periods of late-Variscan granitoid intrusion. The regional significance of these periods is emphasized by contemporaneous ages previously found in the adjacent northeastern Bavarian granitoids. The initial Sr and Nd isotope systematics indicate that the Bor and the Waidhaus-Rozvadov plutons were derived from different source rocks.
   The Bor graniotids reflect the influence of less evolved crustal material which may have been similar to paragneisses of the Teplá-Barrandian region, including the Zone of Erbendorf-Vohenstrauss (ZEV). The Waidhaus-Rozvadov granitoids probably resulted from anatexis of rocks resembling surrounding Moldanubian paragneisses or metapelites. In addition, the two plutons exhibit poorly defined, opposite trends of ENd(T) variation which are ascribed to assimilation processes
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    18. 2. 2008
Import date
    8. 8. 2012