Record details

Title
    Composition of Nb, Ta, Ti, Sn-bearing oxide minerals from the Homolka phosphorus-rich granite, Czech Republic
Statement of responsibility
    Pavel Uher
Other titles
    Proceedings of the International Conference "Genetic Significance of Phosphorus in Fractionated Granites" (IGCP Project No.373) (Variant.)
Author
    Uher, Pavel
Language
    anglicky
Source title - serial
    Acta Universitatis Carolinae, Geologica
Vol./nr.
    Vol. 42, no. 1
Pages
    p. 169-172
Year
    1998
Notes
    2 diagr., 1 fot., 1 tab., 10 bibl.
    Zkr. název ser.: Acta Univ. Carol., Geol.
Subject group
    chemismus hornin
    cín
    fosfor
    granit
    moldanubický pluton
    niob
    oxidy
    tantal
    titan
Geographical name
    ČR-Čechy
    Homolka
Keyword
    Composition
    Czech
    Granite
    Homolka
    Minerals
    Nb
    Oxide
    Phosphorus-rich
    Republic
    Sn-bearing
Abstract (in english)
   The Homolka magmatic centre represents a highly evolved P-rich granite of Upper Carboniferous age. Since it is enriched in Nb, Ta and Sn, the granite contains disseminated rare-element minerals. In course of the electron microprobe study were identified ferrocolumbite to ferrotantalite, ixiolite (or disordered Ti-rich ferrocolumbite), niobian-tantalian rutile, pseudobrookite and cassiterite. Ferrocolumbite-ferrotantalite shows atom. Mn/(Mn+Fe) = 0.14-0.30, Ta(Ta+Nb) = 0.12-0.53 and elevated WO3 = 0.5-4.9 wt.%. Ixiolite (or disordered ferrocolumbite) is also W-rich ( 6.7 wt.% WO3) but depleted in Mn and Ta: Mn(Mn+Fe) = 0.01-0.11 and Ta/(Ta+Nb) = 0.19-0.24. Oscillatory zoned rutile is strongly enriched in Nb and Ta (13-17 wt.% Nb2O5 and 10-18 wt.% Ta2O5), and contains also 3 wt.% SnO2. Pseudobrookite is poor in W, Nb, Ta and Sn, but locally markedly Zn-rich ( 8.7 wt.% ZnO). Cassiterite is nearly pure, depleted in Nb and Ta.
   Described minerals crystallized under magmatic, low- O2 conditions, only ixiolite was exsolved at subsolidus stage and pseudobrookite originated probably by post-magmatic oxidation of ilmenite in a higher O2 environment
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    18. 2. 2008
Import date
    8. 8. 2012