caa a22 4500 445389877 CHVBK 20180317143043.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s00710-011-0152-z doi (NATIONALLICENCE)springer-10.1007/s00710-011-0152-z Nb-Ta-Ti oxides fractionation in rare-metal granites: Krásno-Horní Slavkov ore district, Czech Republic [Elektronische Daten] [Miloš René, Radek Škoda] Nb-Ta-Ti-bearing oxide minerals (Nb-Ta-bearing rutile, columbite-group minerals) represent the most common Nb-Ta host in topaz-albite granites and related rocks from the Krásno-Horní Slavkov ore district. Tungsten-bearing columbite-(Fe), W-bearing ixiolite, wodginite and tapiolite-(Fe) are extremely rare in these rocks. Rutile contains significant levels of Ta (up to 37wt.% Ta2O5) and Nb (up to 24wt.% Nb2O5), with Ta/(Ta + Nb) ratio ranging from 0.04 to 0.61. Columbite-group minerals are represented mostly by columbite-(Fe) and rarely by columbite-(Mn), with Mn/(Mn + Fe) ratio ranging from 0.23 to 0.94. The exceptionally rare Fe-rich, W-bearing ixiolite occurs only as inclusions in Nb-Ta-bearing rutile from quartz-free alkali-feldspar syenites (Vysoký Kámen stock). Wodginite was found only in the topaz-albite microgranite of gneissic breccia matrix that occurs in the upper most part of the Hub topaz-albite granite stock. In wodginite, the Mn/(Mn + Fe) ratio is 0.42-0.51, whereas the coexisting tapiolite-(Fe) has a distinctly lower Mn/(Mn + Fe) ratio close to 0.06. Springer-Verlag, 2011 René Miloš Institute of Rock Structure and Mechanics, Public Research Institution, Academy of Sciences of the Czech Republic, V Holešovičkách 41, 182 09, Prague 8, Czech Republic aut Škoda Radek Institute of Geological Sciences, Masaryk University, Brno, Czech Republic aut Mineralogy and Petrology Springer Vienna 103/1-4(2011-11-01), 37-48 0930-0708 103:1-4<37 2011 103 710 https://doi.org/10.1007/s00710-011-0152-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00710-011-0152-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- René Miloš Institute of Rock Structure and Mechanics, Public Research Institution, Academy of Sciences of the Czech Republic, V Holešovičkách 41, 182 09, Prague 8, Czech Republic aut NATIONALLICENCE 700 1- Škoda Radek Institute of Geological Sciences, Masaryk University, Brno, Czech Republic aut NATIONALLICENCE 773 0- Mineralogy and Petrology Springer Vienna 103/1-4(2011-11-01), 37-48 0930-0708 103:1-4<37 2011 103 710 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer