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 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.

scholarly journals Unique Association of Sulphosalts from the Kľačianka Occurrence, Nízke Tatry Mts., Slovak Republic

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1002
Author(s):  
Jiří Sejkora ◽  
Martin Števko ◽  
Jaroslav Pršek ◽  
Róbert Hovorič ◽  
Emil Makovicky ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Powder Diffraction ◽  
Electron Microprobe ◽  
Slovak Republic ◽  
X Ray ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
Unique Association ◽  
Hydrothermal Veins

Unique association of sulphosalts was discovered at the Kľačianka occurrence, Nízke Tatry Mts., Slovak Republic. It is bound to thin hydrothermal veins with Sb mineralization hosted by the Variscan muscovite-biotite granodiorite and granite of Prašivá type. Ore mineralogy and crystal chemistry of ore minerals are studied here by ore microscopy, X-ray powder diffraction, electron microprobe analyses, and Raman spectroscopy. The early ore mineralization composed of pyrite and arsenopyrite is hosted in quartz gangue and is followed by abundant association of sulfosalts. Stibnite, zinkenite, robinsonite (including Cu-bearing variety), jamesonite, scainiite, dadsonite, disulfodadsonite, rouxelite, chovanite, semseyite, boulangerite, geocronite, tintinaite (with low Bi contents), tetrahedrite-(Fe), tetrahedrite-(Zn), bournonite, chalcostibite, bismuthinite, and gladite in association with sphalerite and rare galena and gold are identified here. The chlorine-rich character of the described sulphosalt association is its characteristic phenomenon. It is represented not only by the occurrence of Cl-sulphosalt and dadsonite, but increased Cl contents were detected in boulangerite, chovanite, disulfodadsonite, robinsonite, rouxelite, scainiite, or tintinaite. The presence of oxygen-containing sulphosalts, such as rouxelite, scainiite and chovanite, is also interesting. The crystallization of these rare chloro-, oxy- and oxy-chloro-sulphosalts at the Kľačianka occurrence required very specific conditions (elevated O2/S2 fugacity) and high chlorine activity in ore-forming fluids.

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 GEOLOGY AND ORE MINERALISATION OF NEOGENE SEDIMENTARY ROCK HOSTED LS EPITHERMAL GOLD DEPOSIT AT PANINGKABAN, BANYUMAS REGENCY, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 7 (2) ◽  
pp. 75
Author(s):  
Arifudin Idrus ◽  
Fahmi Hakim ◽  
I Wayan Warmada ◽  
Mochammad Aziz ◽  
Jochen Kolb ◽  
...  
Keyword(s):  
Base Metal ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Epithermal Gold ◽  
Central Java ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Miners

Low suphidation (LS) epithermal gold deposits were recently found in the Paningkaban area, Central Java province, Indonesia, with more than five hundred artisanal gold miners currently operating in the area. This study is aimed to understand the geological factors controlling the gold mineralization and to characterize the alteration and ore mineralogy of the deposit. Several epithermal veins/veinlets trending N–S, NW–SE, and NE–SW are hosted by Tertiary turbiditic volcanoclastic sedimentary rocks of the Halang formation. This formation is composed of looping gradation of sandstone and siltstone units. Pre- and syn-mineralization structures such as extension joints, normal sinitral fault and sinitral fault control the gold mineralization. Fault movements formed dilational jogs manifested by NW-SE-trending en-echelon tension gash veins. Four main alteration zones are identified: (a) phyllic, (b) argillic, (c) sub propylitic and (d) weak subpropylitic. Ore minerals consist of native gold, electrum, native silver, pyrite, chalcopyrite, sphalerite, galena, arsenopyrite, cubanite, marcasite, covellite and tennantite, which are commonly associated withargillic alteration. Vein structures such as massive, swarm and low angle veins, stockwork and veins dispersed in diatreme breccia are present. Normal banded, cockade, crustiform, bladed carbonates as well as, comb and saccharoidal features are the typical vein textures. It is noteworthy that the veins are basically composed of carbonate with minor quartz at gold grades of up to 83 g/t Au. Based on the vein structures and textures, four stages of ore mineralization were developed consisting of (a) early stage (fluidized breccia and quartz vein), (b) middle stage (carbonate base metal), (c) late stage (late carbonate), and supergene stage. Gold mineralization originated mainly during middle and late stages, particularly in association with cockade, crustiform, bladed carbonate base metal veins. Based on those various features, the LS epithermal deposit in the study area is categorized as carbonate-base metalgold mineralization type.

Ore Mineralization in Adular-Fluorite Metasomatites: Evidence of the Podgolechnoe Alkalic-Type Epithermal Gold Deposit (Central Aldan Ore District, Russia)

2017 ◽  
Vol 743 ◽  
pp. 417-421 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Yackov Yur’evich Bushuev
Keyword(s):  
Ore Deposits ◽  
Epithermal Gold ◽  
Gold Ore ◽  
Ore Bodies ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Host Rocks ◽  
Ore District

The Podgolechnoe deposit, which belongs to the alkalic-type (A-type) epithermal gold-ore deposits, lies in the Central Aldan ore district (Russia). Gold-ore mineralization is associated with a volcano-plutonic complex made of rocks of the monzonite-syenite formation (J3–K1). The ore bodies are localized in the crushing zones developed after crystalline schists, gneisses, and granites of the crystalline basement complexes (Ar–Pr). Metasomatic alterations in host rocks have potassic specialization. Vein ore minerals are adular, fluorite, roscoelite, sericite, and carbonate. Ore minerals are pyrite, galena, sphalerite, cinnabar, brannerite, monazite, bismuth telluride, stutzite, hessite, petzite, montbraite, and native gold. The deposit has been explored as a gold-ore deposit, however, due to complex composition of ores there is a need to reveal the possibilities of the integrated development of this deposit. This could provide for a reserve increment and an increase in the gross recoverable value of ores due to the extraction of associated components.

Ore Mineralization of the Epithermal Samolazovskoe Gold-Ore Deposit, Aldan Shield (Russia)

2018 ◽  
Vol 769 ◽  
pp. 213-219 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Konstantin Chernigovtsev
Keyword(s):  
Aldan Shield ◽  
Crystalline Basement ◽  
Linear Type ◽  
Ore Deposit ◽  
Gold Ore ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Full Volume ◽  
Ore District

The Samolazovskoe gold-ore deposit is located in the Central Aldan ore district (Russia) within the Yukhta multiphase volcano-plutonic massif, consisted of rocks of the monzonite-syenite formation (J3–K1). Four hydrothermal-metasomatic mineral parageneses are distinguished in the deposit: skarn, developed at the contact of syenites and rocks of the carbonate cover (V–Є); gumbeite, superimposed on the rocks of the intrusive massif; feldspatholite, developed in granite gneisses of the crystalline basement (PR) at their contact with the intrusive massif; ore-bearing fluorite–roscoelite–carbonate–quartz, superimposed on all above-mentioned types of mineralization. The main types of mineralization in the Samolazovskoe deposit are the following: (1) vein-disseminated linear type (now recovered in full volume); (2) vein-disseminated stockwork type; and (3) breccia-like type. Vein-filling minerals of the ores are quartz, fluorite, roscoelite, and carbonate. The main ore minerals are pyrite and marcasite; the secondary ones are bournonite, fahlore, sphalerite, galena, and chalcopyrite. Coloradoite and calaverite are less common; native gold occurs very rarely. Pyrite and marcasite are characterized by the following impurities (wt%): Sb (0.64–1.90), As (0.94–5.25), Te (1.02–3.82), and V ( 0.21–0.31).

scholarly journals New data on ore mineralogy and mineral chemistry of pyrite from the Pishtene ore occurrence, Western Srednogorie, Bulgaria

2021 ◽  
Vol 82 (3) ◽  
pp. 147-149
Author(s):  
Ralica Sabeva
Keyword(s):  
Mineral Chemistry ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
High Concentrations

The Pishtene ore occurrence is situated north-northeast from the Pishtene paleovolcanic center in the western part of the Srednogorie zone. The occurrence is hosted by altered basaltic trachyandesites. The styles of alteration are advance argillic, argillic, sericitic and propylitic. Ore mineralization is in quartz-sericite zone and is represented by quartz-pyrite and quartz-polymetallic. The ore minerals are pyrite, chalcopyrite and sphalerite. Pyrite from quartz-polymetallic stage is with high concentrations of Cu, Se and Co. Au with low contents is also detected.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

scholarly journals GRANITOIDS, RARE-METAL PEGMATITES AND Ta-Nb MINERALIZATION OF SHPOLIANO-TASHLYK ORE AREA (INGUL MEGABLOCK, UKRAINIAN SHIELD)

2018 ◽  
pp. 24-29
Author(s):  
O. Hrinchenko ◽  
S. Bondarenko ◽  
T. Mironchuk
Keyword(s):  
Rare Metal ◽  
Ukrainian Shield ◽  
Wide Range ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Isomorphic Series ◽  
Single Complex ◽  
Complex Features ◽  
First Time ◽  
Range Of Values

Composition of granites, genetically associated pegmatites and superimposed metasomatites distributed within Shpoliano-Tashlyk ore area (Ingul megablock) is considered. It is established, that on the basis of similarity in their petrographic and petrochemical features granitoids of the area can be related to single complex. Features of ore mineralization are defined by both composition of granitoids (Sgranites) after which rare-metal pegmatites are formed and intensity of superimposed metasomatic alterations. Main minerals-concentrators of Ta and Nb mineralization in granitic pegmatites and metasomatites are represented by minerals of three isomorphic series – columbite-tantalite (Fe,Mn)(Nb,Ta,Ti)2O6, ilmenorutile-struverite (Ti,Nb,Ta)O2 and pyrochlore-microlite (Ca,Na)2Ta2O6(O,B,OH,F). Depending on geological setting such ore minerals as tapiolite, ixiolite, cassiterite, uraninite, nigerite, gahnite are commonly found in association with these minerals. Chemical composion of tantalo-niobates sampled from ore-bearing pegmatites and metasomatites is investigated by microprobe analysis. Most minerals of columbite-tantalite series are characterized by distinct and rhythmic internal zonality and contrasting mosaic structure which are related to considerable heterogeneities of their chemical composition. Within one aggregate mineral phases with wide range of values – from 9,80 to 71,0 % for Ta2O5 and from 10,6 to 70,1 % for Nb2O5 – are established. Among minerals ferruginous varieties which composition relates to Fe-columbite-tantalites (Nb2O5/Ta2O5 = 1–1,2; FeO/MnO = 2,5–6) prevail. Columbite-tantalites are characterised by high contents of admixture elements present (%): TiO2 – to 5,88; WO3 – to 3,70; SnO2 – to 9,20; Sc2O3 – to 5,40. Scandium ores occur as scandium-rich minerals that are mostly confined to the minerals of columbite-tantalite series found in Polohivka ore field. On the Ukrainian Shield high contents of Sc2O3 in tantalo-niobates are established for the first time. Minerals of ilmenorutile-struverite series do not quantitatively yield to minerals of columbite-tantalite series. For minerals of this series Nb2O5/Ta2O5 ratio varies in the range of 0,6-1,4. Among characteristic admixture-elements are prevailed (%): SnO2 – to 3,1, V2O5 – to 5,05; FeO – to 11,51, Cr2O3 – to 1,20. Minerals of pyrochlore-microlite series are of subordinate importance. For the first time by results of U-Pb dating of columbite-tantalites from Mostove ore manifestation (Shpoliano-Tashlyk area) the age of Ta-Nb mineralization is established to be about 1965 ± 25 million years.

scholarly journals Minerály kontaminovaných granitových pegmatitů z lomu Pohled u Havlíčkova Brodu (moldanubikum), část II: prvky a sulfidy

2021 ◽  
Vol 29 (1) ◽  
pp. 90-107
Author(s):  
Zdeněk Dolníček ◽  
Jana Ulmanová ◽  
Karel Malý ◽  
Jaroslav Havlíček ◽  
Jiří Sejkora
Keyword(s):  
Raman Spectrum ◽  
Metamorphic Rocks ◽  
Mineral Association ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Mineralogical Study ◽  
Native Bismuth ◽  
Polymetallic Ore ◽  
Hydrothermal Veins ◽  
Cobalt And Nickel

In the Pohled quarry near Havlíčkův Brod town (central part of Czech Republic), texturally and mineralogically simple contaminated anatectic pegmatites form dikes or irregular bodies cementing breccia of host metamorphic rocks (paragneisses, amphibolites) belonging to the Monotonous (Ostrong) Group of the Moldanubicum of the Bohemian Massif. They exhibit signs of intense hydrothermal overprint and also the presence of abundant disseminations, nests and veinlets of ore minerals. A detailed mineralogical study revealed the presence of an extraordinary rich ore assemblage (20 species in total, including one unnamed phase). The oldest minerals are sphalerite (rich in Fe), löllingite, Fe-Co-Ni sulphoarsenides (cobaltite, glaucodot, arsenopyrite, gersdorffite), pyrrhotite, galena and chalcopyrite, in later portion accompanied by inclusions of Bi-minerals (native bismuth, bismuthinite, joséite-A, joséite-B, ikunolite and a Pb-Bi sulphosalt). The composition of the Pb-Bi sulphosalt is equal to Ag,Fe-substituted eclarite; its identity was confirmed also by Raman spectrum. Pyrite is very abundant phase, present probably in several generations. The Fe-Co-Ni thiospinels disseminated in younger chlorite, and represented by siegenite, violarite, grimmite and an unnamed NiFe2S4 phase, are the youngest ore minerals. The mineral association as well as chemical composition of most ore minerals are well comparable to those of local polymetallic ore veins and Alpine-type veins, which give evidence for identical origin of all these ore mineralizations. The formation of pegmatite-hosted ore assemblage was long-lasting multiphase process, which took place at temperatures between ca. 350 and <120 °C during changing fugacities of sulphur, tellurium and oxygen. A distinct enrichment in cobalt and nickel of ore mineralization hosted by pegmatites (in comparison with hydrothermal veins) is explained in terms of pronounced interactions of fluids with amphibolites and serpentinites.

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