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Saléeite, Mg(UO2)2(PO4)2, from the Wojcieszyce uranium deposit (Lower Silesia, Poland)

Siuda R., Domańska-Siuda J., Borzęcki R.

Annales Societatis Geologorum Poloniae

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2016

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Vol. 86, No. 2

211--218

EN

The secondary uranium mineral, saléeite, was found in dumps of the former Wojcieszyce Uranium Mine. It occurs as tiny tabular crystals, up to 0.3 cm in size. The chemical formula, which was calculated on the basis of a 12 spot analyses is: (Mg0.73Fe0.05K0.04Ca0.04)S0.86(UO2)2.16(PO4)2.00·10H2O. The cation position is occupied mainly by Mg. The Mg ions are partially substituted by Fe, K and Ca. The tetrahedral position is occupied by the PO43- ion. The interaction between acidic pore solutions (originating from the reaction of pyrite oxidation), uraninite and minerals of the host rocks (chlorite, apatite) leads to the release of Mg2+, UO22+ and PO43- ions. These ions are adsorbed by amorphous Fe oxyhydroxides and poorly ordered ferrihydrite. Crystallization and recrystallization of these phases leads to the release of adsorbed ions and favours the crystallization of saléeite. The coexistence of saléeite and goethite, which forms by recrystallization of ferrihydrite, points to an important role of sorption and desorption of Mg2+, PO43- and UO22+ ions in the process of crystallization of this mineral species. Crystallization of saléeite occurs at a pH of 5.5–6.0. The supergene zone of the Wojcieszyce deposit is the first occurrence of saléeite in Poland.

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Hydrothermal metasomatism of a peralkaline granite pegmatite, Khaldzan Buragtag massif, Mongolian Altai; complex evolution of REE-Nb minerals

Bagiński B., Jokubauskas P., Domańska-Siuda J., Kartashov P., Macdonald R.

Acta Geologica Polonica

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2016

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Vol. 66, no. 3

473--491

EN

The low-temperature hydrothermal alteration of certain rare-metal minerals is recorded in a quartz-epidote metasomatite from the Tsakhirin Khuduk occurrence in the Khaldzan-Buragtag Nb-REE-Zr deposit, Mongolian Altai. A peralkaline granitic pegmatite was metasomatized by hydrothermal fluids released from associated intrusions, with the formation of, inter alia, chevkinite-(Ce), fergusonite-(Nd) and minerals of the epidote group. The textural pattern indicates recrystallization and coarsening of these phases. Later, low-temperature alteration byfluids resulted in the chevkinite-(Ce) being replaced by complex titanite-TiO2-cerite-(Ce)-hingganite-hydroxylbastnäsite-(Ce) assemblages. Calcite formed late-stage veins and patches. The hydrous fluids were poor in F and CO2 but had high Ca contents.

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Geochemistry and petrology of the Upper Silurian greywackes from the Holy Cross Mountains (central Poland) : implications for the Caledonian history of the southern part of the Trans-European Suture Zone (TESZ)

Kozłowski W., Domańska-Siuda J., Nawrocki J.

Geological Quarterly

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2014

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Vol. 58, No. 2

311--336

EN

The Ludlovian greywackes of the Holy Cross Mountains (HCM) represent a part of the sedimentary cover of the Łysogóry and Małopolska terranes located in the Trans-European Suture Zone, central Poland. The rocks form the sedimentary infill of the Caledonian foreland basin that developed at the Tornquist margin of Laurussia and had source-areas located on the orogen side of the basin. Until the present, the source terrane of the basin has not been identified in its potential location – at the south-west margin of the East European Platform. The Ludlovian greywackes of both parts of the HCM show a lot of similarities in clast spectrum, timing, and geochemical features, which implies similar sources of the clastic material. The petrographic modal composition and geochemical features indicate recycled orogen signatures with a distinct undissected, evolved magmatic arc component. The latter is particularly evident from the extraclast spectrum that contains andesite, trachyte and dacite clasts. Beside the volcanic rocks, the source area consisted of sedimentary and metasedimentary rocks with high amounts of cherts. The geochemical and petrological features in the rock succession point to an evolution of the tectonic setting from an active to a more passive margin type indicating synorogenic formation of the studied rocks. Based on the rock record, we suggest that the Upper Silurian greywackes originated as a result of the collision of the Tornquist margin of Laurussia with a volcanic arc (here: the Teisseyre Arc) – located probably at the easternmost extent of the Avalonian Plate. In this scenario, the arc-continent orogen was composed of an uplifted filling of the forearc basin, an accretionary prism, volcanic arc rocks, and an exhumed foreland basement - analogously to the present-day Taiwan orogen. The second key issue is the palaeogeographical relation between the Małopolska (Kielce Region) and the Łysogóry terranes in the Late Silurian. Despite the analogous grain composition and clast types, the Łysogóry Region greywackes are composed of distinctly more altered detritus, which is in accordance with the more distal character of the Łysogóry Basin. The latter is manifested, e.g., in the lack of Caledonian deformations. The present-day adjacency of both domains containing correlative greywacke formations coupled with contrasting alteration and Late Silurian transport directions parallel to the terrane boundary imply small to medium-scale (below palaeomagnetic resolution) left-lateral movements of the Małopolska and Łysogóry crustal blocks along the Holy Cross Fault in post-Silurian times.

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Branneryt z Wołowej Góry i towarzyszące mu minerały uranu (Karkonosze)

Domańska-Siuda J.

Biuletyn Państwowego Instytutu Geologicznego

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2012

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nr 448 (2)

393--399

PL

Występowanie brannerytu na terenie Polski stwierdzono jedynie na zboczach Wołowej Góry, położonej około 3 km na południowy zachód od Kowar (pasmo Karkonoszy). Jego obecność została potwierdzona badaniami rentgenograficznymi. Celem przedstawionej pracy jest szczegółowe określenie składu chemicznego brannerytu z Wołowej Góry oraz ustalenie wzoru empirycznego. Na podstawie badań w mikroobszarze określono również skład minerałów powstających podczas rozkładu brannerytu. W obrębie badanych faz stwierdzono występowanie metaautunitu oraz sabugalitu, który został po raz pierwszy opisany ze stanowiska Wołowa Góra.

EN

Brannerite is a rare mineral that can be regarded as one of the uranium ores. In Poland, its occurrence is confirmed only among the quartzose veins located on the slopes of Wołowa Góra, 3 km southwest of Kowary, in the Karkonosze range. Its presence was confirmed thanks to X-ray diffraction analyses. The purpose of this paper is estimation of the chemical composition of the brannerite. Using the EPMA (Electron Probe MicroAnalysis) technique also specifies the composition of minerals formed during the weathering of the brannerite have also been specified. Among its most common decomposition products, metaautunite and sabugalite were found, reported for the first time from Wołowa Góra.