Record details

    Tourmaline of dravite-uvite series in graphitic rocks of the Velké Vrbno Group (Silesicum, Czech Republic)
Statement of responsibility
    Zdeněk Losos, Julie B. Selway
Other titles
    Turmalíny dravit-uvitové řady z grafických hornin velkovrbenské skupiny (silesikum, Česká republika)
    Losos, Zdeněk
    Selway, Julie B.
Source title - serial
    Journal of the Czech Geological Society
    Vol. 43, no. 1-2
    p. 45-52
    1 obr., 4 fot., 3 diagr., 17 bibl.
    České resumé
    Zkr. název ser.: J. Czech geol. Soc.
Subject group
    chemismus hornin
Geographical name
    Malé Vrbno (Jeseník)
    Petříkov (Jeseník)
Abstract (in english)
   Graphite gneisses of the Velké Vrbno Group, metamorphosed in lower amphibolite facies (garnet to staurolite zone) from the Petříkov and Malé Vrbno graphite deposits contain accessory tourmaline (dravite I). Dravite I columns contain fine graphite inclusions (euhedral graphite flakes up to 0.003-0.01 mm) in the core of the crystals. The second type of tourmaline range in composition from dravite 95 uvite component relative 61 uvite 38 with minor, but constant, schorl component (0.5-3 mol.%). Rims of dravite I crystals are enriched in uvite component relative to the core. The contents of V (0.00-0.40 wt.% V2O3), and Cr (0.05-0.14 wt.% Cr2O3) very low in tourmaline. The tourmaline and graphite in the host rocks were formed during progressive regional metamorphism (T about 500-540°C, P about 0.5 to 0.7 GPa). The tourmaline's chemical compositions fall into a field between low- and medium-grade metamorphosed metapelites and marbles.
   The primary boron content in these metasediments can be explained by an increased salinity within a regressive shelf-sea
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    18. 2. 2008
Import date
    8. 8. 2012