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@article{562268, author = {Novák, Milan and Povondra, Pavel and Selway, Julie Beryl}, article_number = {2}, keywords = {Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum; Czech Republic}, language = {eng}, issn = {0935-1221}, journal = {European Journal of Mineralogy}, title = {Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech Republic}, volume = {16}, year = {2004} }
TY - JOUR ID - 562268 AU - Novák, Milan - Povondra, Pavel - Selway, Julie Beryl PY - 2004 TI - Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech Republic JF - European Journal of Mineralogy VL - 16 IS - 2 SP - 323-333 EP - 323-333 SN - 09351221 KW - Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites KW - examples from the Moldanubicum KW - Czech Republic N2 - 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 ĄV 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 tourmaline show combination of heterovalent substitutions: YAlWO YR2+-1W(OH)-1, XďYAl2WO XNa-1YR2+-2W(OH)-1, XďYAl XNa-1YR2+-1 and Xď 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(Na0.5ď0.5)Y(R2+2Al)ZAl6(BO3)3Si6O18V(OH)3W(O0.5OH0.5) crystallized in very similar PT conditions in granitic systems saturated on Na, Al, 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 electron-microprobe 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. ER -
NOVÁK, Milan, Pavel POVONDRA a Julie Beryl SELWAY. Schorl-oxy-schorl to dravite-oxy-dravite tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech Republic. \textit{European Journal of Mineralogy}. 2004, roč.~16, č.~2, s.~323-333. ISSN~0935-1221.
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