Record details

    Petrochemické typy granitoidů v jižní části středočeského plutonu
Statement of responsibility
    Jiří Machart
Other titles
    Chemical types of granitoids in the southern part of the Central Bohemian Pluton
    Machart, Jiří
Source title - monograph
    Horniny ve vědách o Zemi
    s. 107-116
    4 obr., 3 tab., 2 s.bibl.
    Anglické resumé
Subject group
    analýza sdružovací
    chemismus hornin
    diagram petrochemický
    středočeský pluton
    vápenato-alkalický typ
Geographical name
    Blatná (Strakonice)
    Sedlčany (Příbram)
Abstract (in english)
   Five types of granitoids (A to E) were defined according to the cluster analysis of 104 silicate analyses of calc-alkali granitoids in the southern part of the Central Bohemian Pluton. The basicity and mafic index of the rocks continuously increase from the most felsic type A to the most mafic type E. According to clustering, light coarse-grained and porphyritic granitoids from the Chanovice apophysis correspond to the marginal granite. The Těchnice granidiorite is closely related to the most extended Blatná granodiorite. Another homogenous group consists of the dark facies of Blatná granodiorite, light variety of the Červená granodiorite from the transitional zone, the Klatovy granodiorite and light varieties of the Kozárovice and Vltava granodiorite. Sedlec granodiorite and dark varieties of the Kozárovice and Vltava quartz-monzodiorite have an extreme position (see dendrogram in Fig.1).
   The balanced content and ratio of alkalies (k-value of about 0,43) are characteristic of all types studied. From this point of view they belong to a petrochemically homogenous group. The composition of parenatal magma of the group probably corresponds to that of the homogenous Blatná granodiorite. The basicity and mafic index increasing towards type E may be explained by contamination of perenatal magma by biotite-rich rocks of monzogabbroic character. The most felsic rocks of type A may have formed by differentiation or may be products of an accumulation of alkali-feldspar megacrysts. According to the trend analysis, it is necessary to seek sources of contamination along the S and E contact of the pluton with the Moldanubicum and along the NW contact of the Klatovy apophysis with the Upper Proterozoic, as well as within the area of the Central Bohemia "Islet zone"
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    25. 3. 2008
Import date
    8. 8. 2012