| |
Rezumat articol ediţie STUDIA UNIVERSITATIS BABEĹž-BOLYAI
În partea de jos este prezentat rezumatul articolului selectat. Pentru revenire la cuprinsul ediţiei din care face parte acest articol, se accesează linkul din titlu. Pentru vizualizarea tuturor articolelor din arhivă la care este autor/coautor unul din autorii de mai jos, se accesează linkul din numele autorului. |
|
| |
Rezumat: Beryl is one of the most abundant and widespread minerals of beryllium in granite pegmatites.
Ideally, beryl formula can be written as T(2)Be3OAl2[T(1)Si6O18], but the chemical composition and structure of most beryl samples are, however, more complicated. Whereas Si in T(1) is virtually untouchable, extensive substitutions affect the Be – and Al – polyhedra and vacancies in channels (Černý, 2002). Therefore, from a crystal-chemical reason, beryl formula is briefly represented as:
C(ٱ, Na, Cs, H2O) T(2)(Be,Li)3 O(Al, Sc, Fe3+, Cr, Fe2+, Mg, Mn)2 T(1)[Si6O]18
In granite pegmatites from Carpathian Province of Romania (Mârza, 1980), beryl is found in some pegmatite bodies located in the Getic Subprovince (Teregova field – Semenic Mountains; Voislova and Tâlva field – Poiana Ruscă Mountains; Despina, Pietrele albe, Haneş, Streaja – Lotru Mountains) (Schadler, 1930; Superceanu, 1957; Maieru et al., 1968; Pomârleanu, 1969; Hann, 1987; Murariu, 2001) and Gilău-Muntele Mare Subprovince (Bondureasa Valley – Mârza et al., 1988).
Commonly, beryl occurs as large crystals in the intermediate zones of zoned pegmatite bodies, but was also found as small patches on fractures in albite. In pegmatites from Teregova, beryl (11 kg) is assocated with quartz and K-feldspar, with plagiocalse, quartz and muscovite; or with columbite, tantalite and montebrasite (Superceanu, 1957). In pegmatites from Bondureasa Valley beryl (7x3 cm) comprises inclusions of tourmaline, quartz and muscovite (Mârza et al., 1988)
This paper reports on the geochemical features of beryl from Voislova pegmatites (Getic Subprovince). Samples of beryl occur as large green crystals. In thin section, the interior of beryl is filled by albite, (Fe,Mn)-phosphates and apatite. So far, only fluid inclusions of Voislova pegmatite beryl were studied by Pomârleanu (1969), but there are no further geochemical data available for beryl. |
|
