Record details

    Radioactivity patterns - constraints for the magmatic evolution of the two-mica granites in the Central Moldanubian Pluton
Statement of responsibility
    Karel Breiter, Ivan Gnojek, Marta Chlupáčová
    Breiter, Karel, 1956-
    Chlupáčová, Marta
    Gnojek, Ivan
Source title - serial
    Věstník Českého geologického ústavu (Bulletin of the Czech Geological Survey)
    Vol. 73, no. 4
    p. 301-311
    7 obr., 1 diagr., 1 tab., 34 bibl.
    České resumé
    Zkr. název ser.: Věst. Čes. geol. Úst. (Bull. Czech geol. Surv.)
Subject group
    granit dvojslídný
    moldanubický pluton
    profil geochemický
    spektrometrie gama
Geographical name
Abstract (in english)
   Major part of the Central Moldanubian Pluton (CMP) consists of several types of two-mica granites, which have been traditionally divided into texturally-defined "granite types" - the Číměř, the Landštějn and the Mrákotín ones in Bohemia and the Eisgarn granite in Austria. The unambiguous distinction among them, however, raised a lot of difficulties. In the endeavour (1) to make this "granite typology" more objective, (2) to define real intrusive phases and (3) to deliminate their areal extent, the all existing airborne and regional ground gamma-ray spectrometric data from the CMP-area were interpreted. The compiled maps of K, U and Th contents and U/Th ratio values made possible to distinguish several magmatic evolutionary phases and to precise their position. The Lásenice granite being the oldest constituent of the CMP was found to be very poor in the all three natural radioactive elements. Relatively younger porphyric Číměř and non-porphyric Mrákotín s.s.
   granites represent two textural varieties of one, in this case Th-medium and K-rich nelt. The continuing fractination of the melt from which the Číměř granite arose further produced the central body of the Eisgarn granite s.s. and, finally, several small bodies of muscovite granites rich in uranium and poor in thorium. The next new input of the melt produced the deep-rooted stocks (the Melechov, the Čeřínek and the Zvůle ones) built by the coarse-grained granites with moderate contents of U and with the decreased contents of Th
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    18. 2. 2008
Import date
    8. 8. 2012