scholarly journals Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 430 ◽  
Author(s):  
Pažout ◽  
Sejkora ◽  
Šrein
Keyword(s):  
Solid Solution ◽  
Czech Republic ◽  
Chemical Element ◽  
Hydrothermal Fluids ◽  
Tectonic Events ◽  
Mineral Phases ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
Low Sulfidation ◽  
Ore District

Significant selenium enrichment associated with selenides and previously unknown Ag-Pb-Sb, Ag-Sb and Pb-Sb sulfosalts has been discovered in hydrothermal ore veins in the Anthony of Padua mine near Poličany, Kutná Hora ore district, central Bohemia, Czech Republic. The ore mineralogy and crystal chemistry of more than twenty silver minerals are studied here. Selenium mineralization is evidenced by a) the occurrence of selenium minerals, and b) significantly increased selenium contents in sulfosalts. Identified selenium minerals include aguilarite and selenides naumannite and clausthalite. The previously unknown sulfosalts from Kutná Hora are identified: Ag-excess fizélyite, fizélyite, andorite IV, andorite VI, unnamed Ag-poor Ag-Pb-Sb sulfosalts, semseyite, stephanite, polybasite, unnamed Ag-Cu-S mineral phases and uytenbogaardtite. Among the newly identified sulfides is argyrodite; germanium is a new chemical element in geochemistry of Kutná Hora. Three types of ore were recognized in the vein assemblage: the Pb-rich black ore (i) in quartz; the Ag-rich red ore (ii) in kutnohorite-quartz gangue; and the Ag-rich ore (iii) in milky quartz without sulfides. The general succession scheme runs for the Pb-rich black ore (i) as follows: galena – boulangerite (– jamesonite) – owyheeite – fizélyite – Ag-exces fizélyite – andorite IV – andorite VI – freieslebenite – diaphorite – miargyrite – freibergite. For the Ag-rich red ore (ii) and ore (iii) the most prominent pattern is: galena – diaphorite – freibergite – miargyrite – pyragyrite – stephanite – polybasite – acanthite. The parallel succession scheme progresses from Se-poor to Se-rich phases, i.e., galena – members of galena – clausthalite solid solution – clausthalite; miargyrite – Se-rich miargyrite; acanthite – aguilarite – naumannite. A likely source of selenium is in the serpentinized ultrabasic bodies, known in the area of “silver” lodes in the South of the ore district, which may enable to pre-concentrate selenium, released into hydrothermal fluids during tectonic events. The origin of the studied ore mineralization is primarily bound to the youngest stage of mineralization of the whole ore district, corresponding to the Ag-Sb sequence of the ´eb´ ore type of the Freiberg ore district in Saxony (Germany) and shows mineralogical and geochemical similarities to low-sulfidation epithermal-style Ag-Au mineralization.

scholarly journals Selenium-Rich Ag–Au Mineralization at the Kremnica Au–Ag Epithermal Deposit, Slovak Republic

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 572 ◽  
Author(s):  
Martin Števko ◽  
Jiří Sejkora ◽  
Zdeněk Dolníček ◽  
Pavel Škácha
Keyword(s):  
Base Metal ◽  
Slovak Republic ◽  
Epithermal Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
Chemical Trends ◽  
New Phase ◽  
Epithermal Au ◽  
Ore District

Selenium-rich Au–Ag mineralization has been discovered in the Kremnica ore district, central Slovakia. The mineralization is hosted by a single quartz–dolomite vein hosted by Neogene propyllitized andesites of the Kremnica stratovolcano. Ore mineralogy and crystal chemistry of individual ore minerals have been studied here. The early base-metal ore mineralization composed of pyrite, sphalerite, and chalcopyrite lacks selenium, whereas the superimposed Au–Ag paragenesis is Se-enriched. The Au–Ag alloys, uytenbogaardtite, minerals of the galena–clausthalite series, acanthite–naumannite series, diaphorite, miargyrite, pyrargyrite–proustite, polybasite group, minerals of the tetrahedrite group and andorite branch (andorite IV, andorite VI, Ag-excess fizélyite), freieslebenite, and rare Pb–Sb sulphosalts (scaiinite, robinsonite, plagionite) have been identified here. Besides selenides, the most Se-enriched phases are miargyrite, proustite–pyrargyrite, and polybasite–pearceite, whose Se contents are among the highest reported worldwide. In addition, one new phase has been found, corresponding to a Se-analogue of pearceite containing 2.08–3.54 apfu Se. The style of mineralization, paragenetic situation, and chemical trends observed in individual minerals are comparable to those of Au–Ag low-sulphidation epithermal Au–Ag mineralizations of the Kremnica and neighboring Štiavnica and Hodruša-Hámre ore districts. However, the pronounced enrichment in selenium is a specific feature of the studied vein only.

scholarly journals Structural Controls of Ore Mineralization in a Polydeformed Basement: Field Examples from the Variscan Baccu Locci Shear Zone (SE Sardinia, Italy)

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 456 ◽  
Author(s):  
Antonio Funedda ◽  
Stefano Naitza ◽  
Cristina Buttau ◽  
Fabrizio Cocco ◽  
Andrea Dini
Keyword(s):  
Shear Zone ◽  
Hanging Wall ◽  
Ore Deposits ◽  
Hydrothermal Fluids ◽  
Orogenic Gold ◽  
Mine Area ◽  
Structural Controls ◽  
Mylonitic Foliation ◽  
Ore Mineralization ◽  
Ore Mineralogy

The Baccu Locci mine area is located in a sector of the Variscan Nappe zone of Sardinia (the Baccu Locci shear zone) that hosts several type of ore deposits mined until the first half of the last century. The orebodies consist of lenses of Zn–Cu sulphides, once interpreted as stratabound, and Qtz–As–Pb sulphide ± gold veins; the implication of structural controls in their origin were previously misinterpreted or not considered. Detailed field mapping, structural analyses, and ore mineralogy allowed for unraveling how different ore parageneses are superimposed each other and to recognize different relationships with the Variscan structures. The sulphide lenses are parallel to the mylonitic foliation, hosted in the hinges of minor order upright antiforms that acted as traps for hydrothermal fluids. The Qtz–As–Pb sulphide veins crosscut the sulphide lenses and are hosted in large dilatational jogs developed in the hanging wall of dextral-reverse faults, whose geometry is influenced by the attitude of reverse limbs of late Variscan folds. The ores in the Baccu Locci shear zone are best interpreted as Variscan orogenic gold-type; veins display mutual crosscutting relationships with mafic dikes dated in the same district at 302 ± 0.2 Ma, a reliable age for the mineralizing events in the area.

Výrazně zonální tetraedrit-tennantit z Kramolína, rudní revír Michalovy Hory (Česká republika)

2021 ◽  
Vol 29 (2) ◽  
pp. 249-254
Author(s):  
Luboš Vrtiška ◽  
Jiří Sejkora
Keyword(s):  
Czech Republic ◽  
Single Crystal ◽  
High Variability ◽  
Hydrothermal Fluids ◽  
Crystalline Quartz ◽  
Western Bohemia ◽  
Mine Dump ◽  
Ore District

The crystals of significantly zonal tetrahedrite-tennantite were found in the mine dump material of the Grubenwall 42 mine, Kramolín, the Michalovy Hory ore district, western Bohemia (Czech Republic). Tetrahedrite-tennantite forms layer of tetrahedral, partly corroded crystals up to 1 mm in size on a crust of crystalline quartz in association with chalcopyrite and cerussite. Individual zones in oscillatory zoned crystals are represented by three members of tetrahedrite group minerals - tetrahedrite-(Zn), tennantite-(Zn) and rare tennantite-(Fe). The observed range of AsSb-1 substitution is unusual within a single crystal and indicates high variability of the As/Sb ratio in the hydrothermal fluids.

scholarly journals Selenium-Rich Ag-Au Mineralization at the Kremnica Au-Ag Epithermal Deposit, Slovak Republic

2018 ◽  
Author(s):  
Martin Števko ◽  
Jiří Sejkora ◽  
Zdeněk Dolníček ◽  
Pavel Škácha
Keyword(s):  
Base Metal ◽  
Slovak Republic ◽  
Epithermal Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
Chemical Trends ◽  
New Phase ◽  
Epithermal Au ◽  
Ore District

Selenium-rich Au-Ag mineralization has been discovered in the Kremnica ore district, central Slovakia. The mineralization is hosted by a single quartz-dolomite vein hosted by Neogene propyllitized andesites of the Kremnica stratovolcano. Ore mineralogy and crystal chemistry of individual ore minerals have been studied here. The early base-metal ore mineralization composed of pyrite, sphalerite and chalcopyrite lacks selenium, whereas the superimposed Au-Ag paragenesis is Se-enriched. The Au-Ag alloys, uytenbogaardtite, minerals of the galena-clausthalite series, acanthite-naumannite series, diaphorite, miargyrite, pyrargyrite-proustite, polybasite group, minerals of the tetrahedrite group and andorite branch (andorite IV, andorite VI, Ag-excess fizélyite), freislebenite, and rare Pb-Sb sulphosalts (scaiinite, robinsonite, plagionite) have been identified here. Besides selenides, the most Se-enriched phases are miargyrite, proustite-pyrargyrite, and polybasite-pearceite, whose Se contents are among the highest reported worldwide. In addition, one new phase has been found, corresponding to a Se-analogue of pearceite containing 2.08 - 3.54 apfu Se. The style of mineralization, paragenetic situation, and chemical trends observed in individual minerals are comparable to those of Au-Ag low-sulphidation epithermal Au-Ag mineralizations of the Kremnica and neighboring Štiavnica and Hodruša-Hámre Ore Districts, however, the pronounced enrichment in selenium is a specific feature of the studied vein only.

Pb-Sb zrudnění z Antimonitové žíly, důl Rudolf, Bohutín (Česká republika)

2021 ◽  
Vol 29 (2) ◽  
pp. 275-280
Author(s):  
Pavel Škácha ◽  
Jiří Sejkora
Keyword(s):  
Czech Republic ◽  
Chemical Composition ◽  
Empirical Formula ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Ore District ◽  
Archive Material

The Pb-Sb mineralization with dominant stibnite and plagionite and associated semseyite and zinkenite was found in an archive material collected at the Antimonitová vein, Bohutín, Březové Hory ore district (Czech Republic). Plagionite forms subhedral aggregates up to 1 mm in size. The unit-cell parameters of plagionite for monoclinic space group C2/c refined from the X-ray powder data are: a 13.4890(17), b 11.8670(14), c 19.997(2) Å, β 107.199(8)° and V 3057.9(6) Å3. Its chemical composition (average of 26 analyses, based on 30 apfu) corresponds to the empirical formula Pb5.02Sb8.15S16.82. Associated zinkenite is forming subhedral crystals up to 1 mm in size. Its empirical formula can be expressed as (Cu0.25Ag0.02Fe0.01)Σ0.28Pb9.22Sb22.19S41.31 (average of 26 analyses, based on 73 apfu). Semseyite aggregates have the empirical formula (Pb8.72Fe0.14)8.86Sb8.42S20.73 (average of 11 analyses, based on 38 apfu).

Staročeskéite, Ag0.70Pb1.60(Bi1.35Sb1.35)Σ2.70S6, from Kutná Hora, Czech Republic, a new member of the lillianite homologous series

2018 ◽  
Vol 82 (4) ◽  
pp. 993-1005 ◽  
Author(s):  
Richard Pažout ◽  
Jiří Sejkora
Keyword(s):  
Czech Republic ◽  
Homologous Series ◽  
Electron Probe ◽  
New Mineral ◽  
Orthorhombic Space Group ◽  
Calculated Density ◽  
New Mineral Species ◽  
Reflected Light ◽  
Ore District ◽  
The Ideal

ABSTRACTA new mineral species, staročeskéite, ideally Ag0.70Pb1.60(Bi1.35Sb1.35)Σ2.70S6, has been found at Kutná Hora ore district, Czech Republic. The mineral occurs in the late-stage Bi-mineralization associated with other lillianite homologues (gustavite, terrywallaceite, vikingite, treasurite, eskimoite and Bi-rich andorite-group minerals) and other bismuth sulfosalts (izoklakeite, cosalite and Bi-rich jamesonite) in quartz gangue. The mineral occurs as lath shaped crystals or anhedral grains up to 80 µm × 70 µm, growing together in aggregates up to 200 µm × 150 µm across. Staročeskéite is steel-grey in colour and has a metallic lustre, the calculated density is 6.185 g/cm3. In reflected light staročeskéite is greyish white; bireflectance and pleochroism are weak with greyish tints. Anisotropy is weak to medium with grey to bluish grey rotation tints. Internal reflections were not observed. The empirical formula based on electron probe microanalyses and calculated on 11 apfu is: (Ag0.68Cu0.01)Σ0.69(Pb1.56Fe0.01Cd0.01)Σ1.58(Bi1.32Sb1.37)Σ2.69(S6.04Se0.01)Σ6.05. The ideal formula is Ag0.70Pb1.60(Bi1.35Sb1.35)Σ2.70S6, which requires Ag 7.22, Pb 31.70, Bi 26.97, Sb 15.72 and S 18.39 wt.%, total 100.00 wt.%. Staročeskéite is a member of the lillianite homologous series with N = 4. Unlike gustavite and terrywallaceite, staročeskéite, similarly to lillianite, is orthorhombic, space group Cmcm, with a = 4.2539(8), b = 13.3094(8), c = 19.625(1) Å, V = 1111.1(2) Å3 and Z = 4. The structure of staročeskéite contains four sulfur sites and three metal sites: one pure Pb site and two mixed sites, M1 (0.52Bi + 0.356Ag + 0.124Sb) and M2 (0.601Sb + 0.259Pb + 0.14Bi). The mineral is characterized by the Bi:Sb ratio 1:1 (Bi/(Bi + Sb) = 0.50) and the Ag+ + Bi3+, Sb3+ ↔ 2 Pb2+ substitution (L%) equal to 70%. Thus the mineral lies between two series of the lillianite structures with N = 4, between the lillianite–gustavite series and the andorite series.

Sulfur Isotopic Composition of Sulfides of the Au-Te Ore Mineralization in Podgolechnoe and Samolazovskoe Gold-Ore Deposits (Aldan Shield, Russia)

2018 ◽  
Vol 769 ◽  
pp. 227-232
Author(s):  
Nataliya Rusinova ◽  
Vasilii Ivanovich Leontev
Keyword(s):  
Isotopic Composition ◽  
Significant Contribution ◽  
Isotopic Ratio ◽  
Aldan Shield ◽  
Ore Deposits ◽  
Sulfur Isotopic Composition ◽  
Magmatic Source ◽  
Ore Mineralization ◽  
Sulfur Isotopic Ratio ◽  
Ore District

This work presents the results of an analysis of the sulfur isotopic composition of pyrites from different metasomatic rocks of the Samolazovskoe and Podgolechnoe (Central Aldan ore district) deposits. The sulfur isotopic ratio of pyrite from ore-bearing metasomatic rocks of the Podgolechnoe deposit is characterized by δ34S values varying in a range from –1.8 to –5.5 ‰; that of pyrite from the Samolazovskoe deposit is in a range from –6.9 to –12.3‰. This is in agreement with the suggestion that a magmatic source made a significant contribution to the formation of the ore-forming fluid.

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