Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 23422
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic

Messaggio da Marco E. Ciriotti » mar 06 giu, 2017 16:44

Prossima pubblicazione.

Referenza:
▪ Novák, M., Cícha, J., Čopjaková, R., Škoda, R., Vašinová Galiová, M. (2017): Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic: sole carriers of Be from the magmatic to hydrothermal stage. European Journal of Mineralogy, 29, (in press).

Abstract:
Four distinct paragenetic, morphological and compositional types of milarite-group minerals were distinguished in the NYF pegmatite Velká skála, Písek district, Czech Republic (Moldanubian Zone). The simply zoned (Kfs,Plg,Ab,Qz>Bt>Ap>Tur) pegmatite dike, ∼60 cm thick, is enclosed in durbachite (K,Mg-rich melasyenite). The milarite-group minerals include: yellowish, subhedral, prismatic grains of homogeneous milarite I (milarite s.s.); prismatic subparallel aggregates of white to grayish milarite II (zoned milarite s.s. to Sc-rich milarite, up to ∼20 mol% of the oftedalite component) from small pockets; colorless hexagonal prismatic crystals of milarite III (milarite s.s.) lining open fractures and microscopic fillings in recrystallized K-feldspar locally associated with REE-bearing minerals (allanite, aeschynite, titanite); very rare milarite IV (milarite s.s. to agakhanovite) as prismatic crystals and thin overgrowths with complex oscillatory zoning, ≤200μm in size, on crystals of milarite II and milarite III. Their mineral assemblages, textures and compositions suggest primary (magmatic) for milarite I and hydrothermal origin for milarite II, III, and IV. The simplified compositional evolution in these milarites is: Al+Ca→Be+Sc→Be+Y,HREE→Be+LREE. Milarite-group minerals are the sole carriers of Be in the pegmatite, no relics or pseudomorphs after other Be-rich minerals were found; thus milarite is now established as an additional primary Be-rich mineral in granitic pegmatites. Mineral assemblages, chemical composition of minerals and close relation to the host durbachite suggest a NYF affinity of the Velká skála pegmatite as well as a close relation to euxenite-type pegmatites of the TřebíŠ Pluton. Milarite-group minerals from Velká skála exhibit very similar compositional evolution to those found in the Heftetjern pegmatite, Tørdal, Norway.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 23422
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic

Messaggio da Marco E. Ciriotti » gio 28 set, 2017 10:00

Pubblicazione effettuata.

Referenza:
▪ Novák, M., Cícha, J., Čopjaková, R., Škoda, R., Vašinová Galiová, M. (2017): Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic: sole carriers of Be from the magmatic to hydrothermal stage. European Journal of Mineralogy, 29, 755-766.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Nessuno e 3 ospiti