Gold to aurostibite transformation and formation of Au-Ag-Sb
                        phases: the Krásná Hora deposit, Czech Republic

Zachariáš, Jiří; Němec, Matěj

doi:10.1180/minmag.2016.080.145

Cited by 11 publications

(10 citation statements)

References 26 publications

(34 reference statements)

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“…Evidentially, mustard gold is characteristic of gold-telluride [12][13][14][15] and gold-antimony [16][17][18] deposits, weathering crust [19][20][21] and placers [22,23]. Recently, mustard gold, sometimes with an admixture of Tl (up to 6.34 wt%), was found in the Oleninsky Au-Ag deposit (Kola Peninsula, Russia) [24].…”

Section: Discussionmentioning

confidence: 99%

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Characteristics of Supergene Gold of Karst Cavities of the Khokhoy Gold Ore Field (Aldan Shield, East Russia)

Anisimova¹,

Kondratieva²,

Kardashevskaia³

2020

Minerals

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Typomorphic features of supergene gold in karst cavities were studied in the recently discovered Au–Te–Sb–Tl deposit within the Khokhoy gold ore field of the Aldan-Stanovoy auriferous province (Aldan shield, East Russia). Two morphological types of supergene gold, massive and porous, are recognized there. The first type is represented by gold crystals and irregular mass, with the fineness ranging from 835 to 1000‰. They are closely associated with goethite, siderite, unnamed Fe, Te, and Tl carbonates, Tl tellurites/tellurates and antimonates, as well as avicennite with a Te impurity. The second type is represented by mustard gold of two types with different internal structure: microporous and dendritic. The supergene gold is characterized by persistently high fineness. Along with Ag, it invariably contains Hg (up to 5.78 wt%) and Bi, and, rarely, Pb, Cu, and Fe. The supergene gold is chemically homogeneous, and its particles are all marked by high fineness, without any rims or margins. The obtained characteristics made it possible to prove the existence of two genetic types of supergene gold. Mustard microporous gold is the result of the decomposition of the associated minerals—goethite, Tl oxides, tellurium, Fe, Mn and Tl carbonates and antimonates, containing microinclusions of gold. Massive gold and dendrites are newly formed. The decomposition, remobilization, and reprecipitation of residual gold nanoparticles and their aggregation led to the formation of dendrites, and with further crystal growth and filling of pores, to gold of massive morphology. In terms of morphology, internal structure, fineness, and trace element composition, supergene gold of the Khokhoy gold ore field is comparable to gold from the Kuranakh deposit (Russia) and the Carlin-type gold deposits. It also is similar to spungy and mustard gold from Au–Te and Au–Sb deposits, weathering crusts, and placers. Its main characteristic feature is a close paragenesis with Tl minerals.

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Section: Discussionmentioning

confidence: 99%

“…In the interstices between massive gold there are found dendritic gold particles closely interwoven with goethite ( Figure 5c, Table 3, Nos. [16][17][18][19][20][21][22][23]. The most intricate forms of gold are seen in a very rare mineral avicennite (Tl 2 O 3 ), an oxide of thallium with a Te impurity ( Figure 5d, Table 3; Nos.…”

Section: Massive Goldmentioning

confidence: 99%

Characteristics of Supergene Gold of Karst Cavities of the Khokhoy Gold Ore Field (Aldan Shield, East Russia)

Anisimova¹,

Kondratieva²,

Kardashevskaia³

2020

Minerals

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“…Mustard gold is characteristic in gold-telluride deposits [9,10], antimony-gold deposits [11,12,24,28], and laterites [7,8]. The stibian mustard gold from the Kriván Au deposit, which formed from Au 2 Sb is a composite material consisting of submicroporous sponge of gold with pores infilled by oxidation products of Sb and Fe [24].…”

Section: Discussionmentioning

confidence: 99%

Mustard Gold of the Gaching Ore Deposit (Maletoyvayam Ore Field, Kamchatka, Russia)

Tolstykh

Palyanova

Bobrova³

et al. 2019

Minerals

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The Gaching high-sulfidation (HS) epithermal Au–Ag deposits, part of the Maletoyvayam ore field, which is located in the volcanic belts of the Kamchatka Peninsula (Russia). The main ore components are native gold, tellurides, selenides, and sulphoselenotellurides of Au and oxidation products of Au-tellurides. This study examines the different types of native gold in this ore deposit and the mechanisms and sequential transformation of calaverite (AuTe2) into mustard gold. The primary high fineness gold (964‰–978‰) intergrown with maletoyvayamite Au3Te6Se4 and other unnamed phases (AuSe, Au(Te,Se)) differ from the secondary (mustard) gold in terms of fineness (1000‰) and texture. Primary gold is homogeneous, whereas mustard is spongy. Two types of mustard gold were identified: a) Mixtures of Fe-Sb(Te,Se,S) oxides and fine gold particles, which formed during the hypogenic transformation stage of calaverite due to the impact of hydrothermal fluids, and b) spotted and colloform gold consisting of aggregates of gold particles in a goethite/hydrogoethite matrix. This formed during the hypergenic transformation stage. Selenides and sulphoselenotellurides of gold did not undergo oxidation. Pseudomorphic replacement of calaverite by Au-Sb(Te,Se,S,As) oxides was also observed.

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“…(IRG/ORG) 90 t @ 1.8 g/t Au granodiorite Q0 -minor, pre-ore barren subhorizontal veins Q1 -early ore veins (subvertical, more than 20 cm thick) Q12 -abundant, main ore veins, sheeted complex of vertical 10-3 cm thick veins (they may represent Q1 or Q2 types, or a transition between them) Q2 -very abundant, main ore veins, sheeted complex of densely spaced vertical veinlets < 5 mm thick Q3 -sparse, moderately dipping, post-Q2 veins Morávek et al (1989) Sb-Au (ORG) 1.5 t @ 3-5 g/t Au lamprophyre dykes within granodiorite Q1 -early veins with sparse arsenopyrite (most of them are Au-barren) Q2 -main ore veins associated with deposition of stibnite Q3 -late ore quartz (Q3), fills in fractures in Q2 or Q1, predates/accompany gold Zachariáš and Němec (2017); Němec and Zachariáš (2018) Q1: 300-400 °C, 1-2.5 kbar Q2: 280-330 °C, 0.5-1.3 kbar Q3: 200-240 °C, 0.4-1.0 kbar Příčovy high-fin.…”

Section: High-fineness Aumentioning

confidence: 99%

Trace-element chemistry of barren and ore-bearing quartz of selected Au, Au-Ag and Sb-Au deposits from the Bohemian Massif

Pacák¹,

Zachariáš²,

Strnad³

2019

Jour. Geosci.

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The trace-element contents in gold-bearing and barren quartz veins from eight Au, Au-Ag and Sb-Au Variscan deposits in the Bohemian Massif have been determined in situ in order to evaluate the differences between the various types of gold deposits and discuss trace-element variations in the successive generations of quartz veins. The variability of Ti, Al, Ge, Li and Sb abundances obtained by Laser-Ablation Inductively-Coupled Plasma Mass Spectrometry (LA-ICP-MS) roughly correlates with the origin and the temperature of the mineralizing fluids. The Al content ranges up to 4020 ppm (median value 230 ppm), while the Li content is generally low (< 4 ppm). The elevated Sb content (30-360 ppm Sb) is only related to quartz that immediately preceded deposition of Sb-rich phases. The titanium content of the ore-bearing vein quartz follows bimodal distribution: gold deposits with assumed higher temperature (> 450 °C) formation exhibit higher median values (~10 ppm Ti) than medium-to-low (< 300 °C) temperature deposits (~2 ppm Ti). A statistically significant threshold value (8 ppm Ti) has been recognized as an empirical tool for discriminating between them. In terms of the Ti and Al contents, the studied Bohemian gold deposits fall within and in between fields of orogenic gold and porphyry deposit types.

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Gold to aurostibite transformation and formation of Au-Ag-Sb phases: the Krásná Hora deposit, Czech Republic

Cited by 11 publications

References 26 publications

Characteristics of Supergene Gold of Karst Cavities of the Khokhoy Gold Ore Field (Aldan Shield, East Russia)

Characteristics of Supergene Gold of Karst Cavities of the Khokhoy Gold Ore Field (Aldan Shield, East Russia)

Mustard Gold of the Gaching Ore Deposit (Maletoyvayam Ore Field, Kamchatka, Russia)

Trace-element chemistry of barren and ore-bearing quartz of selected Au, Au-Ag and Sb-Au deposits from the Bohemian Massif

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