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, ≤200 μm 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 an NYF affinity of the Velká skála pegmatite as well as a close relation to euxenite-type pegmatites of the Třebíč Pluton. Milarite-group minerals from Velká Skála exhibit very similar compositional evolution to those found in the Heftetjern pegmatite, Tørdal, Norway.
Article navigation
JOURNAL ARTICLE
Milarite-group minerals from the NYF pegmatite Velká skála, Písek district, Czech Republic: sole carriers of Be from the magmatic to hydrothermal stage
Milan Novák
Milan Novák
1
Department of Geological Sciences, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
Search for other works by this author on:
Jaroslav Cícha
Jaroslav Cícha
2
Prácheň Museum, Velké náměstí 114, 397 24 Písek, Czech Republic
Search for other works by this author on:
Renata Čopjaková
Renata Čopjaková
1
Department of Geological Sciences, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic
Search for other works by this author on:
Radek Škoda
Radek Škoda
1
Department of Geological Sciences, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic*
Corresponding author, e-mail: rskoda@sci.muni.cz
Search for other works by this author on:
Michaela Vašinová Galiová
Michaela Vašinová Galiová
1
Department of Geological Sciences, Faculty of Science, Masaryk University, 611 37 Brno, Czech Republic3
Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic4
Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
Search for other works by this author on:
European Journal of Mineralogy (2017) 29 (4): 755-766.
Published:
August 01, 2017
Article history
-
Views Icon
Views
-
CiteCitation
Milan Novák, Jaroslav Cícha, Renata Čopjaková, Radek Škoda, Michaela Vašinová Galiová; 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 (4): 755–766. doi: https://doi.org/10.1127/ejm/2017/0029-2652
Download citation file:
× -
Share Icon
Share
-
Tools Icon
Tools
Search
Search
Sign in
Don't already have an account? Register
You could not be signed in. Please check your email address / username and password and try again.
Index Terms/Descriptors
- alkaline earth metals
- beryllium
- cathodoluminescence
- Central Europe
- chemical composition
- crystal chemistry
- Czech Republic
- dikes
- electron probe data
- Europe
- granites
- hydrothermal conditions
- ICP mass spectra
- igneous rocks
- intrusions
- magmas
- mass spectra
- metals
- milarite
- milarite group
- mineral assemblages
- Moldanubian
- paragenesis
- pegmatite
- plutonic rocks
- rare earths
- ring silicates
- silicates
- spectra
- substitution
- durbachite
- Pisek Czech Republic
- NYF pegmatite
- Velka skala
Latitude & Longitude