Babingtonite, Y-Al-rich titanite, and zoned epidote from the Strzegom pegmatites, Poland
Janeczek, Janusz; Sachanbinsk, Michae
European Journal of Mineralogy Volume 4 Number 2 (1992), p. 307 - 320
published: Apr 21, 1992
manuscript accepted: Jun 19, 1991
manuscript received: Aug 7, 1990
ArtNo. ESP147050402002, Price: 29.00 €
Abstract Babingtonite, a new mineral to Poland, occurs in miarolitic pegmatites of the Strzegom-Sobotka granitic massif together with microcline-perthite, epidote, titanite, bavenite, stilbite, and calcite. Babingtonite, Ca3.96(Fe3+i.76Fe2+1.4iMgo.42Mno.32Alo.o4) [Si1o.09O29], shows patchy zoning of Mg and Mn substituting for Fe2+. Unit-cell parameters are a 7.470(4) Å, b 12.493(6) Å, c 6.692(3) Å, α 85.73(5)° , β 93.66(5)°, γ 112.33(4)°. D = 3.35 g cm-3. Zoned titanite associated with babingtonite is enriched in both Y and Al. The core of the crystal has Y2O3 6.02, REE 0.88, Al203 5.42 wt % and rims have Y2O3 3.63, 2.34, REE 0.48, 0.40, Al2O3 4.77, 4.57 wt %. Y+REE substitute for Ca and (Al+Fe3+) for Ti in the titanite structure. The zoning pattern of epidote crystals consists of a core surrounded by oscillatory- and sector-zoned rim overgrown by patchy zoned later generation epidote. Some zones are extremely Fe-rich (Ps 50.5). Babingtonite crystallized from locally Al-depleted hydrothermal solution at high H20 activity and oxygen fugacity close to HMM buffer.