Selenide Mineralization in the Příbram Uranium and Base-Metal District (Czech Republic)

Škácha, Pavel; Sejkora, Jiří; Plášil, Jakub

doi:10.3390/min7060091

Cited by 34 publications

(19 citation statements)

References 59 publications

(99 reference statements)

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“…Comparing the three experimental spectra and taking account the amount of Se and S in the samples, there are some interesting outcomes. The observed shifts of the ν 1 symmetric stretching Sb‐(S,Se) (113 cm −1 ) and the ν 3 antisymmetric stretching Sb‐(S,Se) (127 cm −1 ) vibrations at příbramite–chalcostibite agree very well with the value given by Škácha et al for tetrahedrite–hakite (134 and 143 cm −1 ) or Nakamoto for Nb(S/Se) 4 or Mo(S/Se) 4 tetrahedra (more than 100 cm −1 ), and they are distinctly lower, as in the case of permingeatite–famatinite (180 and 220 cm −1 ) …”

Section: Discussionsupporting

confidence: 89%

“…Comparing the three experimental spectra and taking account the amount of Se and S in the samples, there are some interesting outcomes. The observed shifts of [10] the ν 1 symmetric stretching Sb-(S,Se) (113 cm −1 ) and the ν 3 antisymmetric stretching Sb-(S,Se) (127 cm −1 ) vibrations at příbramite-chalcostibite agree very well with the value given by Škácha et al [17] for tetrahedrite-hakite (134 and 143 cm −1 ) or Nakamoto [42] for Nb(S/Se) 4 or Mo(S/Se) 4 tetrahedra (more than 100 cm −1 ), and they are distinctly lower, as in the case of permingeatitefamatinite (180 and 220 cm −1 ). [43] Among members of the chalcostibite-příbramite solid solution (Figure 4), the wavenumber of the ν 1 symmetric Sb-S stretching vibration is not constant: It decreases with an increasing Se content in the mineral-from 336 (in chalcostibite) over 330 (in Se-rich chalcostibite) to 326 cm −1 (in příbramite).…”

Section: Discussionsupporting

confidence: 88%

“…The Se analogue of chalcostibite–příbramite (CuSbSe 2 ) has been described recently . The recent finds of příbramite and an intermediate member along the příbramite–chalcostibite join at the Příbram uranium and base‐metal ore district, Czech Republic, open the possibility of micro‐Raman spectroscopic study of well‐defined natural samples and to relate the spectra to their molecular and crystal structure. Up to now, only Raman spectra of chalcostibite with limited quality and without any interpretation are available in the RRUFF database (chalcostibite R060262)…”

Section: Introductionmentioning

confidence: 99%

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Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Sejkora

Buixaderas

Škácha

et al. 2018

J Raman Spectroscopy

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Micro‐Raman spectroscopy was used to investigate the natural orthorhombic members (space group Pnma) along the CuSbS2–CuSbSe2 join: chalcostibite Cu1.01Sb1.00S1.99 from Dúbrava (Slovak Republic); Se‐rich chalcostibite Cu1.00(Sb0.99As0.02)Σ1.01(S1.29Se0.70)Σ1.99 and the new mineral příbramite Cu0.99(Sb1.03As0.01)Σ1.04(Se1.82S0.15)Σ1.97 both from the Příbram uranium and base‐metal district (Czech Republic). Stretching and bending vibrations of the pyramidal SbS3 groups occur between 350 and 200 cm−1; vibrations of SbSe3 groups are shifted to the range 240–80 cm−1 due to the almost twice heavier mass of Se compared with S. The shift of the ν1 symmetric Sb‐(S,Se) vibration was observed, yielding 113 cm−1, and for the ν3 antisymmetric stretching Sb‐(S,Se), vibration was about 127 cm−1. The wavenumber of the ν1 symmetric Sb–S stretching vibrations decreases with increasing Se content—from 336 (in chalcostibite) over 330 (in Se‐rich chalcostibite) to 326 cm−1 (in příbramite), and a similar situation was observed for the case of ν1 symmetric Sb–Se stretching vibrations from 220 in Se‐rich chalcostibite to 215 cm−1 in příbramite. The trend for the ν3 antisymmetric Sb‐(S,Se) stretching vibrations is the opposite, from 306 cm−1 in chalcostibite to 314 cm−1 in Se‐rich chalcostibite (Sb–S bonds) and from 180 cm−1 in Se‐rich chalcostibite to 185 cm−1 in příbramite (Sb–Se bonds). These small shifts are probably connected with the influencing of the bonding environment of SbS3 and SbSe3 pyramids. The vibrations of Cu‐S(Se) bonds are represented only by less intense bands, and the observed intense bands below 80 cm−1 should correspond to external modes.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Sejkora

Buixaderas

Škácha

et al. 2018

J Raman Spectroscopy

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“…The present occurrence is the first in Australia, and the first from an iron oxide copper gold system. Other occurrences of bellidoite are described by Škácha et al [56], including a recently observed occurrence within the Příbram uranium district, Czech Republic, in which it is intergrown with berzelianite.…”

Section: Formation Of Clausthalite In Cu-(fe)-sulphidesmentioning

confidence: 98%

Nanoscale Study of Clausthalite-Bearing Symplectites in Cu-Au-(U) Ores: Implications for Ore Genesis

et al. 2018

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Symplectites comprising clausthalite (PbSe) and host Cu-(Fe)-sulphides (chalcocite, bornite, and chalcopyrite) are instructive for constraining the genesis of Cu-Au-(U) ores if adequately addressed at the nanoscale. The present study is carried out on samples representative of all three Cu-(Fe)-sulphides displaying clausthalite inclusions that vary in size, from a few µm down to the nm-scale (<5 nm), as well as in morphology and inclusion density. A Transmission Electron Microscopy (TEM) study was undertaken on foils prepared by Focussed Ion Beam and included atom-scale High-Angle Annular Dark-Field Scanning TEM (HAADF-STEM) imaging. Emphasis is placed on phase relationships and their changes in speciation during cooling, as well as on boundaries between inclusions and host sulphide. Three species from the chalcocite group (Cu 2-x S) are identified as 6a digenite superstructure, monoclinic chalcocite, and djurleite. Bornite is represented by superstructures, of which 2a and 4a are discussed here, placing constraints for ore formation at T > 265 • C. A minimum temperature of 165 • C is considered for clausthalite-bearing symplectites from the relationships with antiphase boundaries in 6a digenite. The results show that alongside rods, blebs, and needle-like grains of clausthalite within the chalcocite that likely formed via exsolution, a second, overprinting set of replacement textures, extending down to the nanoscale, occurs and affects the primary symplectites. In addition, other reactions between pre-existing Se, present in solid solution within the Cu-(Fe)-sulphides, and Pb, transported within a fluid phase, account for the formation of composite, commonly pore-attached PbSe and Bi-bearing nanoparticles within the chalcopyrite. The inferred reorganisation of PbSe nanoparticles into larger tetragonal superlattices represents a link between the solid solution and the symplectite formation and represents the first such example in natural materials. Epitaxial growth between clausthalite and monazite is further evidence for the interaction between pre-existing Cu ores and fluids carrying REE, P, and most likely Pb. In U-bearing ores, such Pb can form via decay of uranium within the ore, implying hydrothermal activity after the initial ore deposition. The U-Pb ages obtained for such ores therefore need to be carefully assessed as to whether they represent primary ore deposition or, more likely, an overprinting event. A latest phase of fluid infiltration is the recognised formation of Cu-selenide bellidoite (Cu 2 Se), as well as Fe oxides.

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“…Since 2005, the first author (PŠ) collected a large set of samples containing selenides in the dump material of shafts #16, #11A, and #9. The retrieved material contained a rich selenide assemblage (Škácha and Sejkora 2007;Škácha 2015;Škácha et al 2009, 2014, 2015, 2017a, 2017b, 2018Sejkora et al 2017), including the new mineral, here described pošepnýite.…”

Section: Occurrencementioning

confidence: 99%

Pošepnýite, a new Hg-rich member of the tetrahedrite group from Příbram, Czech Republic

Škácha¹,

Sejkora²,

Plášil³

et al. 2020

Jour. Geosci.

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The new mineral pošepnýite was found in the mine dump of the shaft No. 16 Háje, one of the mines in the Příbram uranium and base-metal district, central Bohemia, Czech Republic. Pošepnýite is associated with příbramite, dzharkenite, ferroselite, hakite-(Hg), tetrahedrite-(Zn), antimonselite and uraninite in a calcite-dominant gangue. The new mineral occurs as idiomorphic to hypidiomorphic grains up to 100 μm in size. Pošepnýite is steel-grey and has a metallic lustre. Mohs hardness is ca. 3.5-4; the calculated density is 6.23 g cm-3. In reflected light, pošepnýite is light brown. No bireflectance, pleochroism, anisotropy or internal reflections were observed. The average empirical formula, based on electron-microprobe analyses (62 spot analyses), is (Cu 3.33 Ag 0.28) Σ3.61 (Hg 3.43 Cu 2.50 Zn 0.03 Cd 0.03 Fe 0.01) Σ6.00 (Sb 3.88 As 0.12) Σ4.00 (Se 10.83 S 1.29) Σ12.12. The ideal formula is (Cu + 3+x □ 3-x) Σ6 (Hg 2+ 4-x Cu + 2+x) Σ6 Sb 4 (Se 12.5 □ 0.5) Σ13 , 0 ≤ x << 2, which requires Cu 12.25, Hg 30.93, Sb 18.77 and Se 38.05, total 100.00 wt. % (for x = 0) or Cu 17.65, Hg 23.87, Sb 19.32, Se 39.16, total 100.00 wt. % (for x = 1). Pošepnýite is cubic, I-43m, a = 10.964(1) Å, with V = 574.82(15) Å 3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern are [d, Å (I) (hkl)] are: 3.165(100) (222), 2.930(24) (321), 2.0017(16) (521), 1.9381(65) (440), 1.6528(31) (622)]. According to the single-crystal X-ray diffraction data (R obs = 0.051), pošepnýite is isostructural with minerals of the tetrahedrite group. The cubic structure of pošepnýite is a tetrahedral framework with cavities and a part of tetrahedra replaced by SbSe 3 coordination pyramids. It has one type of pyramidal Sb position, one type of tetrahedrally coordinated cation position M1 occupied by (Hg, Cu), and one type of partly vacant cation site M2 with triangular coordination. The main anion site Se1 participates in all of these cation coordination polyhedra. Minority anion 'Se2' ties the six coordination triangles of Cu2 in the cavity of the tetrahedral framework into one cluster. Pošepnýite is named after the František Pošepný, a famous 19 th-century geologist, often regarded as the father of the modern economic geology.

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Selenide Mineralization in the Příbram Uranium and Base-Metal District (Czech Republic)

Cited by 34 publications

References 59 publications

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Nanoscale Study of Clausthalite-Bearing Symplectites in Cu-Au-(U) Ores: Implications for Ore Genesis

Pošepnýite, a new Hg-rich member of the tetrahedrite group from Příbram, Czech Republic

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Selenide Mineralization in the Příbram Uranium and Base-Metal District (Czech Republic)

Cited by 34 publications

References 59 publications

Micro‐Raman spectroscopy of natural members along CuSbS2–CuSbSe2 join

Micro‐Raman spectroscopy of natural members along CuSbS2–CuSbSe2 join

Nanoscale Study of Clausthalite-Bearing Symplectites in Cu-Au-(U) Ores: Implications for Ore Genesis

Pošepnýite, a new Hg-rich member of the tetrahedrite group from Příbram, Czech Republic

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Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join

Micro‐Raman spectroscopy of natural members along CuSbS₂–CuSbSe₂ join