Record details

Title
    Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech Republic
Statement of responsibility
    Milan Novák, Pavel Povondra
Author
    Novák, Milan, 1952-
    Povondra, Pavel, 1924-
    Selway, Julie B.
Language
    anglicky
Source title - serial
    European journal of mineralogy
Vol./nr.
    Vol. 16, no. 2
Pages
    p. 323-333
Year
    2004
Notes
    5 obr., 3 tab., 2 s. bibl.
    il.
    Zkr. název ser.: Eur. J. Mineral.
Classfication no.
    549
    552
Conspectus category
    549
    552
Subject group
    chemismus minerálů
    frakcionace chemická
    klasifikace
    krystalochemie
    moldanubikum
    pegmatit
    skoryl
    substituce
    turmalín
Geographical name
    ČR
    Dobrá Voda (Žďár nad Sázavou, Velké Meziříčí)
    Dolní Bory (Žďár nad Sázavou, Velké Meziříčí)
    Laštovičky (Žďár nad Sázavou, Velké Meziříčí)
    Lavičky (Žďár nad Sázavou, Velké Meziříčí)
    Myšenec (Písek, Protivín)
    Pavlínov (Žďár nad Sázavou, Velké Meziříčí)
    Písek-Obrázek
Keyword
    Czech
    Dravite-oxy-dravite
    Examples
    Granitic
    Moldanubicum
    Pegmatites
    Republic
    Schorl-oxy-schorl
    Tourmaline
Abstract (in english)
   Wet-chemical analyses (41) of tourmaline from granitic pegmatites (barren, barren-pocket, beryl, lepidolite types) in the Moldanubicum, Czech Republic revealed that members of the oxy-subgroup - common oxy-schorl, minor oxy-dravite and rare oxy-foitite are more abundant relative to the relevant members of the hydroxy-subgroup. The primary substitution mechanisms in tourmalme show combination of heterovalent substitutions: YAIWO YR2+-1 W(OH)-1, Xsubst.YAl2WO XNa-1 YR2+-2 W(OH)-1, Xsubst.YAl XNa-1,YR2+-1 and Xsubst. W(OH) XNa-1WO-1, and homovalent substitutions: Fe2+Mg-1 and (OH)F-1. Tourmalines with the chemistry expressed by the general formula X(Na0.5subst.0.5)YR2+2Al)ZAl6(BO3)3Si6O18V(OH)3W(O0.5OH0.5) crystallized in very similar PT conditions in granitic systems saturated on Na, AI, Si and H2O, it indicates the importance of short-range order requirements on tourmaline chemical composition.
   Abundance of heterovalent substitutions involving the W-site requires determination of light elements (H, B, F, Li) and Fe2+/Fe3+ in tourmalines to specify substitution mechanisms with certainty. Normalization of electronmicroprobe data of (Fe,Mg)-rich, (Ca,Li,F)-poor tourmalines from granitic pegmatites on (OH,F)3.5O0.5, which is more probable than (OH,F)4, seems to be suitable
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    25. 3. 2008
Import date
    8. 8. 2012