Informace o publikaci
Contrasting textures and compositional evolutions of primary and secondary (metasomatic) tourmalines from elbaite-subtype pegmatites Pikárec and Řečice: Moldanubian Zone, Czech Republic
| Autoři | |
|---|---|
| Rok publikování | 2017 |
| Druh | Další prezentace na konferencích |
| Citace | |
| Popis | The pegmatites of Pikárec and Řečice, their textures and mineral assemblages show some similarities: the overall mineral assemblage, common pockets and Mn-rich Li-tourmalines, and rare micas of polylithionite composition as the only Li-mica. On the other hand, apparent differences in the Pikárec and Řečice pegmatites, respectively, are the internal structure (symmetrically zoned versus subhomogeneous), textures (abundant graphic and skeletal versus equidimensional medium- to coarse-grained), position of pockets (only in the most evolved unit KAE versus in the less evolved MGU and more evolved CGU), distribution of replacement zones (in whole pegmatite body but limited to the contact of tourmaline versus adjacent plagioclase-albite/mostly in FCU as a direct replacement of biotite or tusionite in CGU).Chemical compositions of primary tourmalines show additional noticeable differences. In general, they display compositional trends consistent with the elbaite-subtype pegmatites at both localities (see Novák & Povondra, 1995). However, the behavior in the X-site is contrasting: high Ca at Řečice and low Ca and high X-site vacancy at Pikárec. |