Calculated stability of aqueous tellurium species, calaverite, and hessite at elevated temperatures

Zhang, Xiaomao; Spry, Paul G.

doi:10.2113/gsecongeo.89.5.1152

Cited by 45 publications

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“…Mountain & Wood (1988), Wood et al (1992) and Zhang & Spry (1994) have found in their experiments that parameters of solubility, migration and deposition of hydrosulfide and ammonium complexes are relatively similar for Au, Pt and Pd. The solubility of Au as a bisulfide complex is more likely in environments of massive sulfide ore, being three orders higher than that of Pt and Pd (Gammons & Williams-Jones 1997).…”

Section: Discussionmentioning

confidence: 97%

Gold and Pge in Massive Sulfide Ore of the Uzelginsk Deposit, Southern Urals, Russia

Vikentyev

Yudovskaya

Мохов

et al. 2004

The Canadian Mineralogist

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The Uzelginsk deposit in the southern Urals, in Russia, is an example of a weakly altered classical massive sulfide deposit of the Uralian type. Pyritic Cu-Zn ore contains gold in two main modes: so-called "invisible" gold in sulfides, and mineral forms represented by native gold and tellurides. Gold and PGE concentrations in sulfides from the Uzelginsk deposit have been determined by instrumental neutron-activation analysis (INAA) and wet-chemical analysis with chromatographic and ICP-MS determinations in parallel. Most of the gold occurs invisibly in pyrite and in chalcopyrite, and ranges from 0.7 to 20 ppm and from 1 to 18 ppm, respectively. Sphalerite bearing fine-grained emulsion-like inclusions of chalcopyrite contains 1.8 to 10.6 ppm Au. The gold content of pure grains of sphalerite, as detected by INAA, is between 0.3 and 3 ppm. Tennantite is the main host of Ag; low-iron tennantite (0.1-0.6 wt.% Ag) is the dominant variety, whereas Ag-bearing tennantite (up to 8.4 wt. % Ag) is scarce. Considerable PGE enrichment (up to 354 ppb Pt, 1220 ppb Pd and 707 ppb Rh) was determined in heavy-mineral concentrates from Au-rich mineralization above the quite low levels of PGE background in the ore. Metamorphism of sulfide ores resulted in the redistribution of non-ferrous and precious metals and the formation of submicrometric inclusions of Au-Ag alloy and Au compounds with Te, Se, S, As, Sb and Hg. Some PGE are hosted by pyrite and may be sent to the tailings during processing; the remainder was deposited from a hydrothermal fluid during metamorphism and enriched the products of the latest paragenesis. Sulfide precipitation is shown to have occurred under conditions favorable for the incorporation of gold in solid solution in these minerals at high temperature (250-380 C). The paragenesis of native metals (gold, silver, tellurium and rhenium), tellurides and sulfosalts was formed at the latest stage of the hydrothermal processes, at 165-190 C. SOMMAIRE Le gisement de Uzelginsk, dans le secteur sud des Ourales, en Russie, est un exemple d'un amas classique de sulfures massifs à faible degré d'altération de type Ouralien. Dans le minerai pyritique à Cu-Zn, l'or se présente de deux façons, soit l'or dit "invisible", dans les sulfures, et l'or dans une expresion minéralogique, par exemple l'or natif ou sous forme de tellurures. Les concentrations de l'or et des éléments du groupe du platine (EGP) dans les sulfures de ce gisement ont été établies par activation neutronique et par analyses par voie humide, avec déterminations chromatographiques et par ICP-MS en parallèle. La plupart de l'or est invisible dans la pyrite et la chalcopyrite, entre 0.7 et 20 ppm, et entre 1 et 18 ppm, respectivement. La sphalérite montrant une émulsion d'inclusions très fines de chalcopyrite contient entre 1.8 et 10.6 ppm Au. La teneur en or de la sphalérite pure, telle que détectée par activation neutronique, se situe entre 0.3 et 3 ppm. La tennantite serait l'hôte principal de l'argent; la tennantite à faible teneur en fer (0.1-0.6% Ag, poi...

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Section: Discussionmentioning

confidence: 97%

Gold and Pge in Massive Sulfide Ore of the Uzelginsk Deposit, Southern Urals, Russia

Vikentyev

Yudovskaya

Мохов

et al. 2004

The Canadian Mineralogist

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“…MIZUTA,A. IMAI and Y. ISHIKAWA H 2 Te (aq) with Au(HS) 2 - (Cooke et al, 1996) or directly as aqueous gold-telluride complexes, such as Au 2 (Te 2 )°, Au(Te 2 ) -, and Au(Te 2 ) 2 3- (Seward, 1973;Zhang and Spry, 1994).…”

Section: F S 2 F Co 2 F O 2 F Te 2 and Total Sulfur (σS) Of Orementioning

confidence: 99%

Geology, Mineralogy, and Formation Environment of the Disseminated Gold‐Silver Telluride Bulawan Deposit, Negros Occidental, Philippines

et al. 1998

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: The Bulawan deposit is located in the porphyry copper belt of southwest Negros island, Philippines. Propylitic, K–feldspar, sericitic, and carbonate alteration types can be distinguished in the deposit. Propylite alteration occurs mainly in Cretaceous‐Eocene andesitic lavas and agglomerates while K–feldspar, sericite and carbonate alteration types occur mostly in the Middle Miocene dacite porphyry breccia pipes and stocks which were intruded into the andesites. K‐feldspar zones occur in the inner parts of the sericitized zone. Sericite alteration overprinted the propylitized and K‐feldspar alteration zones, at lower temperature than epidote and chlorite in the propylitized zone. Carbonate alteration is associated with the mineralization in the center of the breccia pipes and along faults. Mineralization consists of gold‐silver telluride ores that are hosted by the carbonate– and sericite‐altered dacite porphyry breccia pipes. The Bulawan ores occur mainly as disseminations, but unlike many epithermal gold deposits, lack classical epithermal colloform and crustiform quartz veins. The ore minerals are sphalerite, galena, chalcopyrite, pyrite and tetrahedite‐tennantite with minor amounts of electrum, calaverite, petzite, sylvanite, hessite, tellurobismuthite, coloradoite, altaite, and rucklidgeite. Electrum and telluride minerals are associated mostly with calcite and dolomite‐ankerite minerals. Fluid inclusions in quartz and calcite in clasts of propylitized andesite in the breccia pipes homogenize from about 300° to 400°C while fluid inclusions in quartz, calcite and sphalerite within the dacite porphyry breccia pipes homogenize between 300° to 310°C. The ores were formed around 300°C from hydrothermal solutions with salinity of about 6. 6 wt % NaCl equivalent. The presence of sylvanite and calaverite as intergrowths with each other, and the Ag content of calaverite are consistent with the above temperature estimate. Based on paragenesis, the Bulawan deposit formed in a pyrite‐stable environment, with pH between 3. 4 and 5. 5, fO2 between 10‐32 to 10‐30 atm, fS2 between 10‐9.8 to 10‐7.8 atm, fTe2 between 10‐8.9 to 10‐6.5 atm, and total sulfur content about 10‐2.8 molal. The dominant reduced sulfur species in the ore solutions may have been H2S(aq), and the likely aqueous tellurium species were H2Te(aq) and H2TeO3(aq). The ore minerals in the Bulawan deposit were probably formed by mixing of slightly saline and low salinity fluids.

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“…Sulfur fugacity could thereby have remained constant or slightly varied within the stability interval of tennantite and pyrite. Thus, enargite passed to tennantite with a drop in against the background of decreasing temperature, whereas the passage of telluride assemblages from the early to the late ones and from the Central to the Southeastern Bereznyakovskoe deposits was largely controlled by As can be seen from the -ç diagram (Zhang and Spry, 1994) shown in Fig. 13, calaverite that occurs at the Central Bereznyakovskoe deposit gives way to a calaverite + native gold assemblage at the Southeastern Bereznyakovskoe deposit due to a decrease in along with an increase in pH within the stability field of pyrite.…”

Section: Discussionmentioning

confidence: 97%

Mineralogy and formation conditions of ores in the Bereznyakovskoe ore field, the Southern Urals, Russia

et al. 2009

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The Bereznyakovskoe ore field is situated in the Birgil'da-Tomino ore district of the East Ural volcanic zone. The ore field comprises several centers of hydrothermal mineralization, including the Central Bereznyakovskoe and Southeastern Bereznyakovskoe deposits, which are characterized in this paper. The disseminated and stringer-disseminated orebodies at these deposits are hosted in Upper Devonian-Lower Carboniferous dacitic-andesitic tuff and are accompanied by quartz-sericite hydrothermal alteration. Three ore stages are recognized: early ore (pyrite); main ore (telluride-base-metal, with enargite, fahlore-telluride, and gold telluride substages); and late ore (galena-sphalerite). The early and the main ore stages covered temperature intervals of 320-380 to 180 ° C and 280-300 to 170 ° C, respectively; the ore precipitated from fluids with a predominance of NaCl. The mineral zoning of the ore field is expressed in the following change of prevalent mineral assemblages from the Central Bereznyakovskoe deposit toward the Southeastern Bereznyakovskoe deposit: enargite, tennantite, native tellurium, tellurides, and selenides → tennantite-tetrahedrite, tellurides, and sulfoselenides (galenoclausthalite) → tetrahedrite, tellurides, native gold, galena, and sphalerite. The established trend of mineral assemblages was controlled by a decrease in , and and an increase in pH of mineral-forming fluids from early to late assemblages and from the Central Bereznyakovskoe deposit toward the Southeastern Bereznyakovskoe deposit. Thus, the Central Bereznyakovskoe deposit was located in the center of an epithermal high-sulfidation ore-forming system. As follows from widespread enargite and digenite, a high Au/Ag ratio, and Au-Cu specialization of this deposit, it is rather deeply eroded. The ore mineralization at the Southeastern Bereznyakovskoe deposit fits the intermediate-or low-sulfidation type and is distinguished by development of tennantite, a low Au/Ag ratio, and enrichment in base metals against a lowered copper content. In general, the Bereznyakovskoe ore field is a hydrothermal system with a wide spectrum of epithermal mineralization styles.

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Calculated stability of aqueous tellurium species, calaverite, and hessite at elevated temperatures

Cited by 45 publications

References 0 publications

Gold and Pge in Massive Sulfide Ore of the Uzelginsk Deposit, Southern Urals, Russia

Gold and Pge in Massive Sulfide Ore of the Uzelginsk Deposit, Southern Urals, Russia

Geology, Mineralogy, and Formation Environment of the Disseminated Gold‐Silver Telluride Bulawan Deposit, Negros Occidental, Philippines

Mineralogy and formation conditions of ores in the Bereznyakovskoe ore field, the Southern Urals, Russia

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