Neobvyklá asociace minerálů s willemitem z prostoru centrální části příbramského uran - polymetalického revíru (Česká republika)

Sejkora, Jiří; Dolníček, Zdeněk; Škácha, Pavel; Ulmanová, Jana; Vrtiška, Luboš

doi:10.46861/bmp.30.224

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…units). Ideal compositions and published data: vrančiceite Cu 10 Hg 3 S 8 (this paper); discredited ‘bayankhanite’ (Kuznetsov et al , 1978; Vasil'ev, 1984); gortdrumite Cu 24 Fe 2 Hg 9 S 23 (Steed, 1983; Bindi et al , 2018); balkanite Cu 9 Ag 5 HgS 8 (Atanassov and Kirov, 1973; Paar and Chen, 1985; Steiner et al , 2010; Biagioni and Bindi, 2017; Sejkora et al , 2022); danielsite (Cu 8.5 Ag 5.5 ) Σ14 HgS 8 (Nickel, 1987; Kato and Nickel, 1988), unnamed (Ag 7.4 Cu 0.6 ) Σ8 Hg 3 (S,Se) 7 (Paar et al , 2004); and imiterite Ag 2 HgS 2 (Guillou et al , 1985). …”

Section: Discussionmentioning

confidence: 91%

Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Sejkora

Biagioni

Škácha

et al. 2023

MinMag

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Vrančiceite is a new mineral species discovered in a sample collected from the old mine dumps of the abandoned Vrančice deposit near Příbram, central Bohemia, Czech Republic. Vrančiceite occurs as rare anhedral grains, up to 100 μm in size, in a calcite gangue, associated with cinnabar, djurleite, galena and hedyphane. Vrančiceite is black, with metallic lustre. Mohs hardness is ca. 2–3, calculated density is 6.652 g.cm–3. In reflected light, vrančiceite is light grey with a yellowish shade; bireflectance, pleochroism and anisotropy are all weak. Internal reflections were not observed. Reflectance values for the four Commission on Ore Mineralogy wavelengths of vrančiceite in air [Rmax, Rmin (%) (λ in nm)] are: 33.6, 31.2 (470); 33.9, 30.6 (546); 31.1, 30.0 (589); and 32.1, 29.1 (650). The empirical formula, based on electron-microprobe analyses, is Cu10.11(4)Ag0.01(1)Hg2.87(4)Sb0.01(1)Bi0.01(1)S7.99(8). The ideal formula is Cu10Hg3S8 (Z = 2), which requires (in wt.%) Cu 42.54, Hg 40.29 and S 17.17, total 100.00. Vrančiceite is triclinic, P $\bar{1}$ , with unit-cell parameters a = 7.9681(2), b = 9.7452(3), c = 10.0710(3) Å, α = 77.759(1), β = 76.990(1), γ = 79.422(1)°, V = 737.01(4) Å3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern [d, Å (I) hkl] are: 3.354 (76) $\bar{2}$ 01, 3.111 (68) 222, 2.833 (100) 213, 2.733 (93) 231, 2.705 (76) 2 $\bar{2}$ 1 and 2.647 (71) $\bar{2}\bar{1}$ 2. According to the single-crystal X-ray diffraction data (R1 = 0.0262), the crystal structure of vrančiceite can be described as comprising Cu–S layers, connected through CuS3 polyhedra, giving rise to a three-dimensional framework with channels running along the a axis and hosting linearly coordinated Hg atoms. Structural relations with gortdrumite are discussed. Vrančiceite is named after its type locality, the Vrančice deposit near Příbram. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2022–114).

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Section: Discussionmentioning

confidence: 91%

Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Sejkora

Biagioni

Škácha

et al. 2023

MinMag

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“…As was already mentioned by [14], such diagenetic fluids could potentially be derived from limestone bodies (olistolites or klippen) present in the study area. Alkaline fluids are also very effective in the dissolution of quartz [72][73][74][75][76].…”

Section: Stage IImentioning

confidence: 99%

Remobilization of HFSE, Y, and REE during Diagenetic Alteration of Heavy Minerals in Sandstones from the Chvalčov Site, Flysch Belt of the Outer Western Carpathians, Czech Republic

Dolníček,

Krejčí Kotlánová,

Ulmanová

et al. 2023

Minerals

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An in situ electron microprobe study of detrital minerals yielded important insights into the diagenetic history of the Cretaceous-to-Paleogene flysch sandstones from the Chvalčov site, Rača Unit, Flysch Belt of the Outer Western Carpathians. Detrital titanite and a Fe-Ti mineral (probably ilmenite) were almost completely altered to TiO2 minerals, which also newly crystallized in intergranular spaces of sandstone. Brookite, anatase, and, exceptionally, rutile were identified by Raman spectroscopy. Authigenic TiO2 phases show complex composition with occasionally elevated contents of Fe, Nb, Zr, V, Sc, Cr, Al, Y, and/or P, which were likely sourced from altered neighboring heavy minerals. In addition, rare authigenic LREE- and Y-enriched apatite rims were observed on detrital apatite. The remobilization of REE, Y, and HFSE was likely mediated by acidic early diagenetic fluids enriched in fluoride and sulfate anions. The superimposed formation of calcite cement was associated with the dissolution of detrital garnet, feldspars, and quartz. The compositions of detrital apatite and garnet (Alm60-82Prp4-30Sps0-24Grs0-19) are comparable with those from adjacent parts of the Flysch Belt. Detrital rutile is enriched in Nb, V, Cr, and Zr. Our study illustrates the intensity of diagenetic alteration of detrital minerals in flysch sandstones as well as the usefulness of in-situ electron-microprobe investigations for the recognition of processes influencing heavy minerals in diagenetically altered sediments.

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Origin of Zn-Pb Mineralization of the Vein Bt23C, Bytíz Deposit, Příbram Uranium and Base-Metal Ore District, Czech Republic: Constraints from Occurrence of Immiscible Aqueous–Carbonic Fluids

Ulmanová,

Dolníček,

Škácha

et al. 2024

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The mineralogical, fluid inclusion, and stable isotope (C, O) study was conducted on a Late Variscan Zn-Pb vein Bt23C, Příbram uranium and base-metal district, Bohemian Massif, Czech Republic. The vein is hosted by folded Proterozoic clastic sediments in exo-contact of a Devonian-to-Lower-Carboniferous granitic pluton. Siderite, dolomite-ankerite, calcite, quartz, baryte, galena, sphalerite, V-rich mica (roscoelite to an unnamed V-analogue of illite), and chlorite (chamosite) form the studied vein samples. The banded texture of the vein was modified by the episodic dissolution of earlier carbonates and/or sphalerite. Petrographic, microthermometric, and Raman studies of fluid inclusions proved a complicated fluid evolution, related to the activity of aqueous fluids and to an episode involving an aqueous–carbonic fluid mixture. Homogenization temperatures of aqueous inclusions decreased from ~210 to ~50 °C during the evolution of the vein, and salinity varied significantly from pure water up to 27 wt.% NaCl eq. The aqueous–carbonic fluid inclusions hosted by late quartz show highly variable phase compositions caused by the entrapment of accidental mixtures of a carbonic and an aqueous phase. Carbonic fluid is dominated by CO2 with minor CH4 and N2, and the associated aqueous solution has a medium salinity (6–14 wt.% NaCl eq.). The low calculated fluid δ18O values (−4.7 to +3.6‰ V-SMOW) suggest a predominance of surface waters during the crystallization of dolomite-ankerite and calcite, combined with a well-mixed source of carbon with δ13C values ranging between −8.2 and −10.5‰ V-PDB. The participation of three fluid endmembers is probable: (i) early high-temperature high-salinity Na>Ca-Cl fluids from an unspecified “deep” source; (ii) late low-salinity low-temperature waters, likely infiltrating from overlying Permian freshwater partly evaporated piedmont basins; (iii) late high-salinity chloridic solutions with both high and low Ca/Na ratios, which can represent externally derived marine brines, and/or local shield brines. The source of volatiles can be (i) in deep crust, (ii) from interactions of fluids with sedimentary wall rocks and/or (iii) in overlying Permian piedmont basins containing, in places, coal seams. The event dealing with heterogeneous CO2-bearing fluids yielded constraints on pressure conditions of ore formation (100–270 bar) as well as on the clarification of some additional genetic aspects of the Příbram’s ores, including the reasons for the widespread dissolution of older vein fill, the possible re-cycling of some ore-forming components, pH changes, and occasionally observed carbon isotope shift due to CO2 degassing.

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Neobvyklá asociace minerálů s willemitem z prostoru centrální části příbramského uran - polymetalického revíru (Česká republika)

Cited by 3 publications

References 27 publications

Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Remobilization of HFSE, Y, and REE during Diagenetic Alteration of Heavy Minerals in Sandstones from the Chvalčov Site, Flysch Belt of the Outer Western Carpathians, Czech Republic

Origin of Zn-Pb Mineralization of the Vein Bt23C, Bytíz Deposit, Příbram Uranium and Base-Metal Ore District, Czech Republic: Constraints from Occurrence of Immiscible Aqueous–Carbonic Fluids

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Neobvyklá asociace minerálů s willemitem z prostoru centrální části příbramského uran - polymetalického revíru (Česká republika)

Cited by 3 publications

References 27 publications

Vrančiceite, Cu10Hg3S8, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Vrančiceite, Cu10Hg3S8, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Remobilization of HFSE, Y, and REE during Diagenetic Alteration of Heavy Minerals in Sandstones from the Chvalčov Site, Flysch Belt of the Outer Western Carpathians, Czech Republic

Origin of Zn-Pb Mineralization of the Vein Bt23C, Bytíz Deposit, Příbram Uranium and Base-Metal Ore District, Czech Republic: Constraints from Occurrence of Immiscible Aqueous–Carbonic Fluids

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Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic

Vrančiceite, Cu₁₀Hg₃S₈, a new Cu–Hg sulfide mineral from Vrančice, Czech Republic