Minerály a geochémia granitového pegmatitu Bratislava - Jezuitské lesy (Slovensko).

The Bratislava - Jezuitské Lesy granitic pegmatite forms a relatively narrow dike (up to 1 - 2 m thick) in parental Her- cynian (~350 Ma) S-type granodiorite to granite. The pegmatite internal zoning consists of a coarse-grained quartz-feld- spar-muscovite zone, locally with transition into a graphic pegmatite, blocky K-feldspar and massive quartz. An aplitic saccharoidal albite (albite » quartz + muscovite + garnet) and cleavelandite extensively replace the older pegmatite zones. Beryl, garnet (almandine > spessartine), zircon (≤12 wt.% HfO2), monazite to cheralite, Nb-Ta-(Sn) oxide minerals (all columbite-tantalite members, ferrotapiolite, ferrowodginite), and gahnite occur in coarse-grained zone as well as saccharoidal albite. The pegmatite is enriched in Rb, Cs, Be, Nb, Ta, Sn and Wand depleted in Li, Sr, Ba, Zr and REE's. These geochemical features and mineral composition show a relatively highly fractionated pegmatite melt and beryl-columbite subtype of the rare-element class and LCT tendency of the pegmatite. Moreover, anomalously high Y/Ho value (60) and presence of the lanthanide tetrad effect (T1,3= 1.17), together with presence of fluorapatite (≤10 wt.% MnO) and fluorcalciomicrolite, indicate an influence of fluorine-rich fluids during late magmatic to early hydrothermal (high-temperature) evolution stage of the pegmatite. On the contrary, phenakite, bertrandite, quartz II, and muscovite II originated during late hydrothermal (low-temperature) overprint of the pegmatite as a result of post-magmatic Hercynian uplift or Alpine tectono-thermal overprint of the Bratislava granitic massif. [ABSTRACT FROM AUTHOR]