Open AccessBohseit z beryl-columbitového pegmatitu D6e v Maršíkově (silezikum, Česká republika)
Author(s) -
Zdeněk Dolníček,
Miroslav Nepejchal,
Jiří Sejkora,
Jana Ulmanová,
Štěpán Chládek
Publication year - 2020
Publication title -
bulletin mineralogie petrologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.239
H-Index - 10
eISSN - 2570-7345
pISSN - 2570-7337
DOI - 10.46861/bmp.28.219
Subject(s) - pegmatite , albite , muscovite , geology , columbite , massif , geochemistry , crystallography , orthorhombic crystal system , amphibole , electron microprobe , mineralogy , quartz , crystal structure , chemistry , phase (matter) , paleontology , organic chemistry
Bohseite was found in a lenticular body of D6e beryl-columbite granitic pegmatite near Maršíkov, which is hosted by amphibole gneisses of the Sobotín Amphibolite Massif (Silesicum, northeastern part of Czech Republic). Bohseite forms chalky white aggregates up to 1 cm in size, which are hosted by small vugs in the coarse-grained pegmatite. It is associated with small crystals of quartz, adularia, albite, muscovite and epidote. Bohseite is orthorhombic, space group Cmcm with following unit-cell parameters refined from X-ray powder diffraction data: a 23.210(2), b 4.955(2), c 19.428(3) Å and V 2234.5(1.0) Å3. The electron microprobe compositional data of bohseite are presented. Bohseite from Maršíkov contains 14.3 - 42.5 mol. % of bavenite component, up to 0.06 apfu Na and 0.13 - 0.36 apfu F. The association with other beryllium-rich phases (milarite, bertrandite) points to variable activities of Be and Al during hydrothermal stage of evolution of the pegmatite body. The likely source of Be was beryl, which is sometimes completely dissolved and vugs after its crystals are lined by small crystals of above mentioned hydrothermal phases.