The Julianna pegmatite vein system at the Piława Górna Mine, Góry Sowie Block, SW Poland – preliminary data on geology and descriptive mineralogy

Abstract

The newly dis cov ered Julianna peg ma titic sys tem from the Pi³awa Górna Quarry (the Góry Sowie Block, Sudetes, NE mar gin of the Bo he mian Mas sif) is de scribed in terms of geo log i cal set ting, pe trog ra phy and de scrip tive min er al ogy. The sys tem repre sents the larg est peg ma titic oc cur rence in the Pol ish Sudetes and con sists of a com plex net work of cogenetic rare-el e ment gra nitic pegmatites that in truded into tectonized am phi bo lite as dis cor dant dikes. The pegmatites range from bar ren and weakly zoned to tex tur ally well-dif fer en ti ated ones that are com posed of a fine-grained bor der zone, coarse-grained wall zone, graphic and blocky feld spar in ter me di ate zones and a quartz core. Uni di rec tional and skel e tal so lid i fi ca tion tex tures are well-de vel oped. The Julianna pegmatites con sist of rock-form ing plagioclase (£An 39 ), microcline, quartz and bi o tite accom pa nied mostly by ac ces sory to mi nor mus co vite, tour ma line, gar net and beryl. They crys tal lised from anatectic melt of hy brid NYF (ni o bium-yt trium-flu o rine) + LCT (lith ium-ce sium-tan ta lum) geo chem i cal char ac ter is tics. Pegmatites with a low to mod er ate de gree of frac tion ation, that dom i nate in the Julianna sys tem, bear NYF-sig na ture ac ces sory min er als, such as al la nite-(Ce), colum bite-, euxenite-and samarskite-group min er als, fergusonite-(Y) and gadolinite-(Y). How ever, rare dikes that at tained a very high de gree of frac tion ation con tain typ i cal min er als of LCT-sig na ture in clud ing tour ma lines of the elbaite-olenite-rossmanite se ries, le pido lite, lithiophilite, spodumene, Cs-rich beryl and pollucite.

Bohseite, ideally Ca4Be4Si9O24(OH4, from the Piława Górna quarry, the Góry Sowie Block, SW Poland

“…The tectonized amphibolites are cut discordantly by anatectic zoned pegmatite dykes, with individual dimensions reaching 30-40 m in vertical section, 80-100 m in longitudinal section and 6 m thick (Szełeg et al, 2010;Pieczka et al, 2012Pieczka et al, , 2013Szuszkiewicz et al, 2013). Pegmatites of the system typically display a zoned internal structure (border zone + wall zone + graphic intermediate zone + blocky-feldspar intermediate zone + quartz core ± quartz-albite zone ± spodumene-'lepidolite' core) with usually low to moderate degrees of geochemical fractionation and enhanced Nb-REE-Be-B contents.…”

“…They consist mainly of microcline, plagioclase ('oligoclase'-'andesine' and albite), quartz, biotite and muscovite accompanied by schorl, garnet (almandine-spessartine series) and beryl. Rare-element minerals are Szuszkiewicz et al, 2013), suggesting NYF affiliation for the parental melt. In the axial parts of the largest dykes, there are signs of more-and muchmore strongly fractionated Li-Cs-Ta-Be-B mineralization of the LCT type, which only formed exceptionally as larger pods.…”

Towards Zn-Dominant Tourmaline: A Case of Zn-Rich Fluor-Elbaite and Elbaite from the Julianna System at Piława Górna, Lower Silesia, SW Poland

“…Migmatite accounts for about 72% of the raw rock and the rest is mainly amphibolite, with minor bodies of granitic pegmatite. The Julianna pegmatitic system is composed of coeval and cogenetic dykes, apophyses and lenticular bodies, up to 6-7 m thick, extending along 30-40 m in vertical section, 80-100 m in planar view along a NNE-SSW running zone of strongly tectonized amphibolite [17]. The pegmatites show a broad range of textural differentiation from homogeneous and subhomogeneous to simply zoned bodies (border zone + wall zone + graphic intermediate zone + blocky-feldspar intermediate zone + quartz core ± quartz-albite zone ± spodumene-"lepidolite" core).…”

“…The pegmatites show a broad range of textural differentiation from homogeneous and subhomogeneous to simply zoned bodies (border zone + wall zone + graphic intermediate zone + blocky-feldspar intermediate zone + quartz core ± quartz-albite zone ± spodumene-"lepidolite" core). Geochemical variability varies from primitive and moderately fractionated pegmatites, enriched in Nb-REE-Be-B and belonging to the NYF (niobium-yttrium-fluorine) pegmatitic family, to rare and much more strongly fractionated pods located in the axial parts of the largest dykes that contain Li-Cs-Ta-Be-B mineralization of the LCT (lithium-cesium-tantalum) type [17][18][19][20]. The pegmatites are formed mainly of microcline, Na-plagioclase, quartz, "biotite" and muscovite, accompanied by schorl, almandine-spessartine garnet and beryl.…”

(Fe,Mn)-(Ti,Sn)-(Nb,Ta) oxide assemblage in a little fractionated portion of a mixed (NYF + LCT) pegmatite from Piława Górna, the Sowie Mts. block, SW Poland

“…Various Nb-Ta minerals, including columbite-group minerals, ixiolite, ferrowodginite, samarskite-, euxenite-and fergusonitegroup minerals, pyrochlore-supergroup minerals, and also Nb-and Ta-enriched varieties of cassiterite, ilmenite and titanite, constitute important accessory minerals and many of them suggest a NYF signature for the parental melt. However, in exceptionally rare cases, when fractionation attained a very high degree, the LCT-signature mineral assemblage including elbaite-liddicoatite, pollucite, spodumene, Cs-beryl and Li-micas is encountered Nejbert et al 2010;Pieczka et al 2010Pieczka et al , 2012Szełęg et al 2010). Thus the complex Julianna system of cogenetic pegmatites is tentatively assigned to the mixed NYF + LCT family (Pieczka et al 2012;Szuszkiewicz et al in print) of Černý and Ercit (2005).…”