Next Article in Journal
Rheological and Strength Properties of Steel-Slag Cemented Paste Backfill: Link to Gypsum Type and Dosage
Next Article in Special Issue
Comparative Experiments on the Role of CO2 in the Gold Distribution between Pyrite and a High-Salinity Fluid
Previous Article in Journal
Study of 405 nm Laser-Induced Time-Resolved Photoluminescence Spectroscopy on Spinel and Alexandrite
Previous Article in Special Issue
Volcano–Plutonic Complex of the Tumrok Range (Eastern Kamchatka): An Example of the Ural-Alaskan Type Intrusion and Related Volcanic Series
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 13
Issue 3
10.3390/min13030420
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Au-Ag-Se-Te-S Mineralization in the Maletoyvayam High-Sulfidation Epithermal Deposit, Kamchatka Peninsula

by
Nadezhda Tolstykh
*,
Maria Shapovalova
and
Maksim Podlipsky
Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
*
Author to whom correspondence should be addressed.
Minerals 2023, 13(3), 420; https://doi.org/10.3390/min13030420
Submission received: 15 February 2023 / Revised: 10 March 2023 / Accepted: 13 March 2023 / Published: 16 March 2023
(This article belongs to the Special Issue Precious Metals vs. Base Metals: Nature and Experiment)
Browse Figures
Versions Notes

Abstract

:
The Maletoyvayam high-sulfidation (HS) epithermal Au-Ag deposit is one of the numerous hydrothermal deposits of the Kamchatka volcanogenic belt, consisting of two main associations: Au-rich (Ag-free) and Ag-bearing. The first one derived from acidic solutions, whereas the second assemblage crystallized from moderately dilute solutions, with both occurring at high oxygen fugacity. The Au-rich association contains the most atypical gold chalcogenides of the Au-Se-Te-S system, which are characterized by Se-S and Te-Se substitutions, e.g., a complete series from maletoyvayamite to tolstykhite Au3(Se,S)4Te6; a series of auroselenide Au(Se1.00–0.64S0.36–0.00); a combined series of gachingite Au(Te,Se) and unnamed Au(Se,Te): Au(Te0.80–0.40Se0.20–0.60). Meanwhile, in the second Ag-bearing assemblage, sulfides of the Au-Ag type prevails, e.g., petrovskaite AuAgS, miargyrite (Ag,Au)(Sb,As)S2, uytenbogaardtite Ag3AuS2, fischesserite Ag3AuSe2 with Au-Ag substitution, and tolstykhite. The Se/S ratio, of the second association, decreases while increasing the Ag concentration in the ore-forming system, including Au-Ag substitutions. The Au content in miargyrite (Au,Ag)SbS3 reaches up to 0.48 apfu, suggesting the existence of a new mineral phase of composition AgAuSb2S6. Au oxide complexes, in both associations, are represented by either a mixture of redeposited gold and Fe-Sb oxide or a homogeneous (Au,Sb,Fe)2O3 composition. These oxides are formed by replacement of calaverite. The ore mineralization of this HS deposit is considered unique due to the special conditions of the ore-forming environment, such as acidic solutions, high oxygen fugacity, and log fSe2 above −5.7; all contributed to the formation of AuSe phases.

1. Introduction

The epithermal Maletoyvayam Au-Ag deposit, located in the northern part of the Central Kamchatka volcanogenic belt (Figure 1a,b), is the only one in the Kamchatka peninsula corresponding to high sulfidation (HS), according to [1]. This deposit is confined to the Vetrovayam volcano-tectonic structure. The Maletoyvayam ore field comprises volcano-sedimentary succesions of the Vetrovayam suite: andesites, tuffs, and tuffsandstones (Figure 1c). Features, such us vuggy silica and stockwork quartz veining, in the central parts of the ore field are followed outwards by alunite-, sericite-kaolin-quartz, and kaolin-quartz rocks, and then by argillites and propylites at the periphery [2]. The Gaching ore occurrence, belonging to the Maletoyvayam deposit, is located near the head of the Gachingalhovayam River and is represented by quartz stockworks, hosted by vuggy silica and strongly oxidized quartz-alunite rocks, typical of HS type deposits [3]. The regional geology, structural features, and ore-forming processes of the Maletoyvayam deposit have been extensively reported. A collection of these data is given in [4,5], where the approximate conditions for the activity of sulfur, selenium, tellurium, and oxygen were estimated on the basis of mineral paragenesis. This approach revealed that the productive ore association was derived from very acidic solutions under oxidizing conditions, which are indicative of HS epithermal deposits [6,7]. Additional work about mustard gold and Au oxides in the paragenesis of the Maletoyvayam deposit [8,9], as well as a study on the compositions of fluid inclusions in quartz, have been published [9,10]. Unnamed gold chalcogenides, never described before for other deposits, have been identified in the different ore associations; some of them were synthesized and their experimental analogues studied [11,12], finally leading to the approval, by the International Mineralogical Association (IMA), of four new gold mineral species: maletoyvayamite Au3Se4Te6 [13], gachingite Au(Te1–xSex) [14], tolstykhite Au3S4Te6 [15], and auroselenide AuSe [16]. The presence of four new mineral species among Au-minerals and unnamed Au-compounds at the Maletoyvayam deposit, which have not yet been reported anywhere else, may be related to the special conditions of their forming environment. Acidic ore-forming solutions and high oxygen activity, typical of HS-type epithermal deposits, were accompanied by very high selenium activity: log fSe2 varying between −12.4 and −5.7 at 250 °C [5]. All of this led to a high Se/S ratio in ore-forming solutions, which triggered the formation of the auroselenide (AuSe) species. Recently obtained mineralogical data also revealed the presence of an Ag-bearing association, in a few samples, in addition to the Au-rich (Ag-free) assemblage. Hence, the aim of this study is to reveal the correlation of Au/Ag and Se/S ratios in mineral parageneses, due to the fact that selenium activity increases when the acidity of solutions is increased [17,18,19]. Furthermore, a detailed description of the reference mineralogical collection of the Maletoyvayam deposit (Gaching occurrence), characterizing the products of acidic hydrothermal solutions, is also of great scientific importance to understand the ore genesis of epithermal deposits.

2. Materials and Methods

Samples of quartz veins and alunite-quartz rocks from the mine trench at the Gaching site (one sample of 20 kg and thirteen of 5 kg each) were provided to the authors for research. Samples of rocks were crushed to a particle size of less than 0.5 mm and were later separated by density, using water and a dense liquid tribromomethane to obtain a heavy mineral concentrate. These concentrates were later prepared as epoxy grain mounts for microprobe analysis, along with polished rock chips, for in situ analysis of paragenetic associations.
The chemical compositions of minerals were analyzed at the Analytical Center for Multi-Elemental and Isotope Research at the VS Sobolev Institute of Geology and Mineralogy SB RAS in Novosibirsk (Russia), using a LEO-413VP scanning electron microscope (SEM) equipped with an INCA Energy 350 X-ray EDS system (Oxford Instruments Ltd., Abingdon, UK) (analysts Dr. N. Karmanov and M. Khlestov), operating at an accelerating voltage of 20 kV, beam current of 0.4 nA, 50 s measuring time, and beam diameter of ~1 μm. The following standards were used: pure metals (Ag, Au, Bi, Se, Sb, Fe, Cu), pyrite (S), synthetic HgTe (Te), and sperrylite (As). The detection limit was 0.02%. The following X-ray lines were selected: Lα for Ag, Te, As, Sb, and Se; Kα for S, Fe, Cu, and O; and Mα for Au and Bi. WDS Microprobe analyses of Au-minerals were carried out in the same analytical center, at 20 kV and 50 nA, in a JEOL JXA-8230 microprobe (beam size ∼1 mm) (analyst V. Korolyuk). The following X-ray lines (and standards) were used: SeLα (Bi2Se3), TeLα (AgTe2), AgLα (Ag), SKα (CuFeS2), and AuMα (Au). The results were treated using ZAF correction routines in the native JEOL software. The detection limit was <0.05% for all analyzed elements. More than 2000 microanalyzes for mineral compositions were carried out. All data in the tables are listed according to the detection limits of the elements.

3. Results

3.1. Minerals in the Au-Te-Se-S System

3.1.1. Maletoyvayamite-Tolstykhite Solid Solution (Mty—Tls ss)

These two minerals have been previously described as unnamed phases Au2Te4(Se,S)3 [5]; however, after performing detailed crystallographic studies, a new chemical formula was assigned for each of the compounds—Au3Se4Te6 for maletoyvayamite [13] and Au3S4Te6 for tolstykhite [15]—both of which turned out to be isostructural. Maletoyvayamite and tolstykhite are the most common minerals of the ore-bearing association, prevailing over native high-grade gold. As shown in Figure 2a, the composition of these minerals is clustered in a specific area of the ternary diagram, showing limited variations in the ratios between Au and chalcogens, as well as in tellurium and the (S + Se) sum. The Se-S substitution is substantial, forming a complete solid solution between maletoyvayamite and tolstykhite (Figure 2b). The grain morphology of both minerals and intergrowths, with associated phases, are comparable (Figure 3). Individual grains are characterized by anhedral shapes (Figure 3a,b). Both maletoyvayamite and tolstykhite are opaque with metallic luster. Cleavage is well-developed on {010} and {001}. In plane-polarized reflected light, both minerals are bluish gray with high birefringence and strong anisotropy [13,15].
There are two types of mineral assemblages: (1) maletoyvayamite and tolstykhite are very often intergrown with Fe-Sb oxides (Figure 3c,d)—FeSbO4 and FeSb2O6, which correspond to tripuhyite compositions, as well as with more oxidized species containing Te, As, Bi, and S as minor elements [8]; (2) intergrowths of maletoyvayamite and tolstykhite with calaverite AuTe2 and native gold (Figure 3e,f). In this case, the selenium analogue varies all the way up to a S-free composition (Table 1), spectra 83, 84, 98, 100, and 104. However, when associated with tripuhyite or Ag-bearing minerals (fischesserite), the role of S in solid solutions increases significantly.
A portion of the most Au-rich compositions on the Mty—Tls ss field (Table 1), spectra 85 and 96, lies on the Au/(S + Se + Te) = 1/3 line (Figure 3a) and moves toward the chemical formula Au(Te,Se,S)3, which can be represented as Au(Se,S)Te2.

3.1.2. Tellurium-Selenium Solid Solution (Te-Se ss)

Native tellurium, as well as the solid solution it forms with selenium, are representative of the entire ore association. Te-Se ss occur as: (1) individual grains, often intergrown with goldfieldite or selenium goldfieldite (Figure 4a,b,d,e,f); (2) as drop-shaped or rounded inclusions in sulfosalts (tetrahedrite and goldfieldite) (Figure 4c); and (3) as xenomorphic segregations intergrown with Mty—Tls ss (Figure 4d–f). The compositional points of Te-Se ss, confined towards the tellurium region of the diagram (Figure 2a), form an almost continuous series from native tellurium up to Se0.58Te0.42. Minor S, up to 0.65 wt. %, is present in Te-Se solid solutions (Table 2). The main associated minerals are goldfieldite, in which Te predominates over Sb and As, and tetrahedrite (Table 2). All of them include Se within the range 1.00–8.93 wt. %. In some cases, the amount of Se (apfu) prevails over the other chalcogens in the chemical formulae (D_9-1, point 4), which may potentially correspond to a new sulfosalt Cu12Se4S13 (Table 2). Te-Se solid solutions occur intergrown, in almost the same proportion, with both tolstykhite and maletoyvayamite.

3.1.3. Calaverite AuTe2

Calaverite occurs in subordinate amounts compared to other gold minerals. It is found as discrete grains (Figure 5a) in intergrowth with maletoyvayamite or tolstykhite (Figure 5b), but most often together with Au-Fe-Sb oxides (Figure 5c–e), which instead replace calaverite, forming rims (Figure 5d) or completing pseudomorphs with minor relics (Figure 5f). The Ag concentration in calaverite does not exceed 4 wt. %, and it is usually less than 1 wt. % (Table 3). Calaverite oxidizes when reacting with infiltrating fluids containing Fe, Sb ± As, Se, S, and Bi, additionally forming Au oxides (Figure 5). Compositions of Au-Fe-Sb(Te,As,Se) complex oxides, associated with calaverite, are shown in Table 3. Minor arsenic is regularly detected in these oxides, with rather rare Ag, Cu, Se content.

3.1.4. Chalcogenides AuX, X—Te,Se,S: Gachingite Au(Te1–xSex), Auroselenide AuSe, and Unnamed Au(Se,Te) Phase

These minerals are considered the rarest of all ore association in the Maletoyvayam deposit and belong to the category of gold chalcogenides with common formula AuX, where X is Se, Te, and S. Auroselenides occur as irregular fragments rimming native gold by replacement (Figure 6a–f). Auroselenides AuSe are also in close association with Mty-Tls ss (Figure 6b,d,e). Gachingite Au(Te1–xSex), where 0.2 ≈ x ≤ 0.5, or more simply (Te0.8–0.5Se0.2–0.5), occurs as individual rounded to drop-shaped inclusions of 10 µm within gold grains (Figure 6f) [14]. Three discrete grains of gachingite, 20–40 µm in size, (Figure 6a–c) intergrown with maletoyvayamite, calaverite, and Au-Sb oxides were recently observed. All Au chalcogenides are difficult to distinguish from each other in reflected light, due to their size and similar optical properties. Auroselenide, gachingite-like, and Mty-Tls ss are bluish-gray with strong anisotropy, displaying bluish to brownish rotation pleochroism. Nonetheless, gachingite has a lighter blue-gray tone (Figure 6f) and a smoother (polished) mineral surface compared to maletoyvayamite, which possesses a flakier surface (Figure 7a).
In addition, the composition of both auroselenide and gachingite lies on the same AuSe – AuTe line in the (S + Se) – Au – Te system (Figure 2a). Monoclinic AuSe [16] shows rather limited compositions, with slight variations around Au and (Se + S) end-members and between (Se + S) and Te, as well as an extended Se → S substitution series up to Au(Se0.64S0.36) (Figure 2b). The morphology of this phase is comparable to auroselenide, but it differs slightly in lighter shade from other associated minerals (auroselenide, maletoyvayamite, tolstykhite) on SEM images (Figure 8), points 1–3 and 6–11. Compositions of gachingite, as shown in the chemical formula approved by the IMA, also form a limited orthorhombic series from Au1.0Te0.5Se0.5 to Au1.0Te0.8Se0.2 [14]. The analytical results of auroselenide and gachingite are given in Table 4 and Table 5.
Minerals 13 00420 g007 550
Figure 7. SEM images. Individual grains of gachingite (Gcg) (a–c) intergrown with maletoyvayamite (Mty) and calaverite (Clv) (a), and Au,Sb,Se-oxide (c). The numbers of the samples and the points with the numbers of the spectrum correspond to the analyses in Table 5.
Figure 7. SEM images. Individual grains of gachingite (Gcg) (a–c) intergrown with maletoyvayamite (Mty) and calaverite (Clv) (a), and Au,Sb,Se-oxide (c). The numbers of the samples and the points with the numbers of the spectrum correspond to the analyses in Table 5.
Minerals 13 00420 g007
Minerals 13 00420 g008 550
Figure 8. SEM back-scatter image. An individual grain of native gold, partially replaced by various gold minerals: maletoyvayamite (Mty), tolstykhite (Tls), auroselenide (AuSe), and unnamed phase Au(Se,Te). The reference number of the sample and the white EDS points correspond to the analyses given in Table 6.
Figure 8. SEM back-scatter image. An individual grain of native gold, partially replaced by various gold minerals: maletoyvayamite (Mty), tolstykhite (Tls), auroselenide (AuSe), and unnamed phase Au(Se,Te). The reference number of the sample and the white EDS points correspond to the analyses given in Table 6.
Minerals 13 00420 g008

3.2. Minerals in the Au-Ag-Sb(As)-S System from the Ag-Bearing Association

3.2.1. Miargyrite, Petrovskaite, Uytenbogaardtite, and Fischesserite from the Ag-Bearing Association

In this study, new mineralogical data were obtained; a few Ag-bearing mineral species, such as petrovskaite AuAgS, Au-bearing miargyrite (Ag,Au)(Sb,As)S2, uytenbogaardtite Ag3AuS2, and fischesserite Ag3AuSe2, were identified in sample MG-63 from the Maletoyvayam deposit. All of them occur in close association with native gold. The first two Ag-bearing species replace gold grains at the margins (Figure 9a,d); uytenbogaardtite is intergrown with gold (Figure 9b,e), whereas fischesserite with maletoyvayamite are grown together. Each of these minerals has its own compositional features, e.g., petrovskaite is characterized by an excess of silver relative to gold (Ag 1.08–1.13 apfu); uytenbogaardtite has Au-Ag variations (Ag 2.87–3.20 apfu) deviated from the ideal Ag3AuS2 formula (Figure 10a, Table 7); fischesserite contains minor S (0.18–0.24 apfu); and miargyrite and petrovskaite are closely intergrown, forming a typical rim after gold. At the same time, miargyrite contains a significant amount of Au (0.39–0.48 apfu) (Figure 10b), as well as As → Sb substitution, up to 10.2 wt. % or 0.43 apfu (Table 7). In addition, unknown phases, such us (Ag,Au)9(S,Se)2Te3 or (Ag,Au)9(S,Se)3Te5, intergrown with tolstykhite, were found in the Ag-bearing association (sample MG-63). These intergrowths, represented by exsolution textures, are only revealed in reflected light (Figure 9c), but not SEM-BSE image (Figure 9f).

3.2.2. Maletoyvayamite—Tolstykhite Solid Solution in Ag-Bearing Samples

Native tellurium, calaverite, and Mty-Tls ss occur in both Ag-free and Ag-bearing associations (Figure 11a). However, a complete series of solid solution is characteristic of the Ag-free association (Mt-8), whereas, in Ag-bearing samples (MG-63), only the sulfur analogue (tolstykhite) is found; on the other hand, Se is absent in calaverite.

3.2.3. Gold Complex Oxides in the Ag-Bearing Association

Complex compositions of Au-oxides have been reported in the Ag-bearing association, as well as in the previously described Ag-free assemblage [8,9]. They occur, forming rims (Figure 12a), as composites with other chalcogenides and gold (Figure 9f), as well as complete pseudomorphs of primary minerals more likely to be calaverite (Figure 12b,c).
The composition of oxides vary considerably, trending from fine-grade or slightly oxidized gold to tripuhyite or even hematite (Figure 13). Many compositions move towards the general formula (Au,Fe,Sb,As,Se,Te)2O3. For example, the composition of the oxide in Figure 9f is represented by the formula (Au1.50Sb0.29Ag0.08Fe0.06As0.03)1.96O3.04 or simply (Au,Sb)2O3. In some grains, the composition gets closer to the formula (Au,Fe,Sb)2O3 or (Au,Fe,As)2O3, where iron prevails over antimony and other elements (Table 8).
Typically, the composition of oxides in the Ag-bearing assemblage are more oxidized, with a higher concentration of Fe, Sb, Te, As, and Se than those from Ag-free associations (Figure 13). The clustering of compositional points near the hypothetical Au3O are usually linked to high-grade “mustard” porous gold. These tiny pores may be filled with iron and antimony hydroxides [8].

4. Discussion

4.1. Possible New Minerals in the Au-Te-Se-S System

The unnamed AuTe2Se compositions, at the current stage of research, also belong to the maletoyvayamite field Au3Se4Te6, expanding its stability towards gold enrichment. Nonetheless, it should be noted that, in these compounds, the substitution Se by S is limited, up to 0.52 apfu of S (Figure 2b). Thus, it is very likely that compounds with empirical formula Au(Se,S)Te2 correspond to a theoretically new mineral in the Au-Te-Se-S system, different from maletoyvayamite.
There are also a series of compositions that, according to its empirical formula AuTexSe1–x, where 0.2> x < 0.5, differ greatly from gachingite, and similarly from auroselenide, mainly owing to its high tellurium content (Table 6). These compositions lie on the range Au(Se0.52Te0.48)–Au(Se0.64Te0.36) (Figure 2a) and are located next to the gachingite series, more precisely, towards its end-member Au(Te0.5Se0.5). This innominate phase is separated from pure auroselenide by an immiscibility region, and it is also distinguished by lower S concentrations (Figure 2b). The morphology of this mineral is comparable to that of auroselenide, although it may be differentiated in back-scatter SEM images due to the lighter shades presented in other associated minerals (e.g., auroselenide, maletoyvayamite, tolstykhite) (Figure 8). Furthermore, it is likely that this solid solution series, of apparent limited compositional range Au(Se0.6–0.5Te0.4–0.5), corresponds to a new mineral phase of formula Au(Se1–xTex) 0.4 ≈ x ≤ 0.5; however, this requires additional experimental research.
The unusual composition of goldfieldite is due to selenium in the formula, complementing the tellurium group, although it does not substitute sulfur. In this case, and by assuming an admixture of Se and S, goldfieldite composition would be far from the empirical formula. This problem, however, should be further discussed in future studies.

4.2. Solid Solutions in Natural Gold Chalcogenides

Selenium minerals may be found in sandstones, skarn, uranium deposits, and at epithermal deposits, where Se-rich parageneses occur in association with Te-rich minerals. However, tellurium and selenium do not form mixtures or compounds, due to the fact that the geochemical behavior of tellurium and selenium is different [17]. In nature, tellurides are more common than selenides, with the former tending to produce its own minerals in epithermal deposits, owing to its incompatibility with selenium in the structure of minerals. Therefore, the formation of tellurides is only caused by a Te-rich source, whereas, to form a selenide mineral, a high ƒSe2(g)/ƒS2(g) ratio is not enough, since additional conditions are also required.
They require a highly oxidizing environment with a high pH to form, which is controlled by the H2Se/H2S ratio in aqueous fluids [17,18,19]. A substantial increase of these ratios contributes to the successive substitution of Au–S by Au–Se complexes [20]. Selenium atoms in the structure of sulfides substitute sulfur in sulfides and sulfosalts, even at low H2Se/H2S values, as observed in many low sulfidation epithermal deposits. In particular, it is typical for the Rodnikovskoye and, to some extent, the Baranievskoye deposits in Kamchatka [21,22].
Additionally, selenium often plays a significant role in the formation of ores in LS epithermal deposits around the world, e.g., Kremnica ore district and Central Slovakia, where the experimental contents of Se in sulfosalts are the highest ever measured worldwide [23]. Selenide minerals in the Hope’s Nose occurrence is part of an epithermal system and is linked to a basic-intermediate igneous rocks, hosted in carbonaceous shale [24], which supports the general idea of a correlation between selenium and organic matter, as well as their general evolution [10]. Furthermore, most of the Au-Ag LS epithermal deposits in Chukotka belong to the Se-bearing type (Korrida, Valunistoye, Dvoynoye, etc.) whose ores contain important amounts of selenium-bearing minerals [25,26]. In the Koch-Bulak deposit in Uzbekistan, the main selenium concentrators are sulfides and sulfosalts [27]. Au-Ag selenide (fischesserite) has been described in the West Tuva ore occurrence [28]. The Se concentration in ores from LS deposits, such us the Baran’evskoe and Rodnikovoe deposits in Kamchatka, is 36 and 25 ppm, respectively. However, selenium reaches the highest concentrations at the Maletoyvayam deposit (92 ppm) [10], which is characterized by Au-selenides and sulfoselenides.
In the Au-Ag-Te-Se-S system for epithermal deposits, as a rule, either tellurides—petzite Ag3AuTe2, krennerite Au3AgTe8, sylvanite AgAuTe4, muthmannite AuAgTe2, montbrayite Au2Te3 (simplified formula); or selenides—fischesserite Ag3AuSe2, naumannite Ag2Se; or sulfides—acanthite Ag2S, uytenbogaardtite Ag3AuS2, and petrovskaite AuAg are found. All these minerals are characterized by three types of elemental substitutions: (1) between Au and Ag, (2) Se → S, and (3) Te → Se. In the first case, the existence of a continuous solid solution from naumannite Ag2Se to α-fischesserite Ag3AuSe2 has been experimentally demonstrated; intermediate compositions between monoclinic calaverite AuTe2 and orthorhombic krennerite Ag3AuTe8 have also been demonstrated [29,30]. In addition, significant Au-Ag exchanges have been reported in natural compositions from various deposits in the Au-Ag-S system, including uytenbogaardtite Ag3AuS2 and petrovskaite AuAgS substitution [31].
The substitution of S for Se and Se for S is more common and typical for LS deposits: monoclinic acanthite series from Ag2S to Ag2S0.4Se0.6 and orthorhombic naumannite series from Ag2S0.3Se0.7 to Ag2Se [32,33]. In the fischesserite—uytenbogaardtite series (Ag3AuSe2–Ag3AuS2), there are two structurally different solid solutions: cubic Ag3AuSe2–Ag3AuSeS and trigonal Ag3AuSe0.75S1.25 – Ag3AuS2 [34]. Uytenbogaardtite Ag3AuS2 allows the substitution of S for Se up to 0.5 apfu (AgAuS0.5Se0.5), while mineral phases with a higher Se concentration are metastable [35].
The alloys containing up to 10–15 at.% Te consist of a Te-Se solid solution (by substitution) of phase A, whereas those bearing Te between 50–100 at.% are solid solutions of phase B. Alloys with 15 to 50 at. % Te consist of a two-phase mixture (A + B) [36]. Most of the Te-Se ss compositions in this study are native tellurium (phase B), and only a few analyses lie in a two-phase field (Figure 1). It is likely that, among natural Te-Se solid solutions in epithermal deposits, the Maletoyvayam compositions are the most Se-rich (up to 45.9 wt. % Se or Se3Te2); meanwhile, in epithermal gold deposits, such as HS Kochbulak and Kairagach, Se does not exceed 10.3 wt. % in native tellurium [37]. Te-Se solid solutions obtained, empirically, the following for silver minerals: Ag2Te – Ag(Te0.8Se0.2) and Ag(Te0.6Se0.4) – Ag2TeSe, with monoclinic and orthorhombic structure, respectively [38]. However, for Au minerals, only a limited substitution of Te for Se is known to occur in calaverite Au(Te0.8Se0.2) [39].
A typomorphic feature of the ore association in the Maletoyvayam deposit, compared to other deposits in the world, is the presence of ternary compounds in the system Au-Te-S-Se (Au sulfoselenotellurides (Figure 2), while Ag plays a very limited role, varying from 0.5 to 1.5 wt. %, never exceeding 3 wt. % (in native alloys and calaverite), whereas, in other minerals, it is usually below the detection limit. In this particular deposit, S-Se solid solutions are widely spread, showing a complete series from maletoyvayamite to tolstykhite, as well as auroselenide, in which the content of S reaches up to 35 apfu—Au(Se0.65S0.35). In addition, there is a Te-Se trend in the recently approved gachingite Au(Te0.80–0.50Se0.20–0.50), and in the unnamed Au(Se,Te) phase, in which Te reaches up to 0.48 apfu Au(Se0.52Te0.48). Thus, it may be assumed that the complete series of solid solutions of gachingite Au(Te,Se) continues into the selenium region of the diagram and mixes with a series of compositions of the unknown Au(Se,Te) phase, forming a single solid solution from (Te0.80Se0.20) to Au(Te0.36Se0.64), with no miscibility break (Figure 2a). Moreover, both of these series are characterized by a single substitution Se-Te trend, which differs from the typical Se-S trend of auroselenide (Figure 2b).

4.3. Calaverite Transformation and the Formation of Au Oxides and Native Tellurium

All compositions of AuTe2 are intimately linked to calaverite, since Ag concentration in these minerals (up to 3.94 wt. %) is inadequate to form krenerite, and it is required that Ag exceeds 6 wt. % in the formula Au3AgTe8. Furthermore, krennerite is always metastable at low temperatures and will not form below 270 °C [40]. On the other hand, calaverite is presumably the main, primary mineral of the ores studied in the Maletoyvayam epithermal deposit, although it occurs no more frequently than other minerals. This is due to the fact that calaverite is weakly stable and, under oxidizing conditions, is replaced by Au-Fe-Sb oxides (Figure 4), which are also very common at the Maletoyvayam deposit. Such replacements, from partial to almost complete pseudomorphs, are observed in different ore associations (Figure 5d–f). In earlier publications, including [8], the initial stage of calaverite replacement was revealed in the shape of worm-like veinlets of secondary products, comprising a mixture of fine particles of native gold and Fe-Sb oxides. One of the mechanisms for primary calaverite replacement is AuTe2 + Fe, Sb, Bi, As, Se, and S-containing solutions + O2 → Au + Te,Se solid solution + TeO2 + Fe(Sb,As)O3. The reaction products correspond to high grade (spongy) gold with Sb–Fe oxide ± admixtures and native Se-rich tellurium [8]. All the textural observations considered, in these replacements, suggests that tellurium, which is released from calaverite during detellurization processes, is not redeposited at the place of substitution. Rather, this one migrates as transferable units and bonds with mobile selenium, all of which are later recombined in the form of Te-Se solid solutions, in association with Te-bearing sulfosalts (goldfieldite) (Figure 4). Moreover, the replacement of calaverite by gold oxide only occurs in hydrothermal solutions [41], but not under near-surface conditions. The porosity of mustard gold is deemed as textural evidence for reactions that lead to a negative volume [42]. Thus, the influx of Fe, Sb, As, Se, Bi-atoms, and the removal of oxidized Te takes place in the reaction, contributing to a local decrease in oxygen activity, and hence, favoring the deposition of Au(I) gold [41]. Depending on the degree of oxidation and the rate of Te removal, the final products can be either (1) a fine mixture of spongy gold (redeposited), along with Fe-Sb oxide (tripuhyite), or (2) homogeneous complex Au oxides. These oxides tend toward a stable state when the amount of oxygen reaches 60 at. %, which corresponds to the formula (Au+Fe+Sb+As,Te,Se)2O3 (Table 4). Micron-sized gold particles are the building blocks in the formation of secondary mustard gold aggregates. At the same time, tripuhyite is oxidized to limonite [8], and high-grade gold either clumps, forming coarse-grained gold due to the accretion of smaller particles, or crumbles into dust-like particles, enriching the dusty fraction of ores as a result.

4.4. Comparison of Typomorphic Features in Ag-Free (Au-Rich) and Ag-Bearing Associations

Ag-bearing association of the Maletoyvayam deposit is typical for one sample out of many studied. Within this silvery assemblage, sulfur prevails over Se in chalcogenides. Au-Ag sulfides are rather common and are represented by petrovskaite AuAgS and uytenbogaardtiteAg3AuS2, which have typical Au-Ag variations [31] and sporadic Se. Only S-rich tolstykhite associates with these minerals (Figure 10b). In the case of miargyrite, the significant range of Se-S substitution is characteristic in other deposits as well: up to 0.75 apfu of Se in the Kremnica ore district, Central Slovakia [23], and up to 0.62 apfu from Kutná Hora, Czech Republic [43]. However, in the Ag-bearing association of the Maletoyvayam deposit, no S-Se substitutions have been observed. On the other hand, miargyrite includes As, which is not typical for Au-rich associations, constituting a solid solution with proustite AgSbS3-AgAsS3, up to 0.43 apfu of As. A particular feature of this mineral is defined by its high Au content (up to 0.48 apfu of Au) (Table 7). Furthermore, we suggest the possibility of this compound representing a potential new mineral whose approximate formula may correspond to AuAgSb2S6. Finally, the presence of mineral compounds, including all five elements of the Au-Ag-S-Se-Te system, such as maletoyvayamite, tolstykhite, gachingite, and auroselenide, within the Ag-bearing association, had not yet been reported in natural samples. All this, once again, is evidence of the uniqueness of this geological body and the ore-forming environment.
Au–Ag LS-type epithermal deposits, which are characterized by Ag-rich and S-rich associations (acantite-augilarite), were derived from neutral pH solutions under conditions of fSe2/fS2 < 1 [19]. At low H2Se/H2S values in aqueous fluids, selenium enters sulfides as solid solutions [17] and does not form Au-selenides. The formation of selenides is aided by a significant increase in the activity of selenium, which is only possible in acidic solutions at elevated fO2, when Au–S complexes are successively replaced by Au–Se. Accordingly, the concentration of Ag in ores is positively correlated with the S/Se ratios in such ore-forming systems. At the same time, S/Se ratios in maletoyvayamite-tolstykhite solid solutions are good indicators of the physicochemical conditions of the ore-forming environment. Since LS-type deposits, where silver mineralization dominates, were derived from neutral pH solutions under conditions of fSe2/fS2 < 1 [19], it means that a must-have condition during the formation of the Ag-bearing (and S-rich) association of Maletoyvayam deposit has to do with a decrease in the acidity of solutions. This could have been achieved by diluting acidic magmatic solutions with meteoric water.

5. Conclusions

Two ore associations are typical of the Maletoyvayam deposit: Au rich (Ag-free) and Ag-bearing. The former crystallized from acidic solutions, whereas the latter formed from more diluted ones.
  • In the Au-rich type, in addition to the usual calaverite AuTe2, triple gold chalcogenides, i.e., compounds of the Au-Se-Te-S system, are typical. This association is characterized by Se-S and Te-Se substitution in minerals. The Se-S trend is confirmed by a complete solid solution between maletoyvayamite and tolstykhite Au3Se4Te6 – Au3S4Te6, as well as by a limited solid solution of auroselenide, from AuSe up to Au(Se0.64S0.36). Te-Se substitution is quite evident in native Te-Se alloys up to 0.58 Se apfu, and in two combined series of solid solutions of gachingite Au(Te,Se) and an unnamed Au(Se,Te) phase with common variations of selenium Se0.20–0.60, as well as in calaverite Au(Te,Se)2, with Se content up to 0.2 apfu.
  • In the Ag-bearing association, an increased role of silver and sulfur is observed. Au-Ag sulfides dominate: petrovskaite AuAgS, miargyrite (Ag,Au)(Sb,As)S2, uytenbogaardtite Ag3AuS2, and fischesserite Ag3AuSe2. Among the Mty-Tls ss, only S-rich tolstykhite is present. Au-Ag sulfides are characterized by Au-Ag substitution. Moreover, miargyrite (Au,Ag)SbS3 contains significant Au, the amount of which is sufficient to form a new unnamed mineral AgAuSb2S6. Additionally, a rare compound (Ag,Au)9(S,Se)2Te3 within the same association has been revealed.
  • Complex Au oxides are rather common in both associations, ranging from a finely dispersed mixture of redeposited gold and tripuhyite to homogeneous compounds of (Au,Sb,Fe)2O3 composition. These oxides are mostly the result of calaverite replacement: the removal of oxidized Te and the addition of Fe,Sb into hydrothermal solutions.

Author Contributions

Conceptualization, writing, review, and funding management: N.T.; field work, laboratory research, and editing: M.S. and M.P. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by the RSF, grant number 23-27-00258.

Data Availability Statement

Not applicable.

Acknowledgments

We thank analysts Karmanov N., Khlestov M., Chubarov V., and Korolyk V. for analytical assessment EDS and WDS of gold minerals; Belkina N. for technical support, Petrova E. and Bobrova O. for providing the ore samples.

Conflicts of Interest

The authors declare no conflict of interest. The Sponsors played no role in the design of the study; collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

  1. Hedenquist, J.W.; Arribas, A.; Gonzalez-Urien, E. Exploration for epithermal gold deposits. SEG Rev. Econ. Geol. 2000, 13, 245–277. [Google Scholar]
  2. Melkomukov, B.H.; Razumny, A.V.; Lopatin, W.B. The new highly promising gold objects of Koryakiya. Min. Bull. Kamchatka 2010, 14, 70–74. (In Russian) [Google Scholar]
  3. Berger, B.R.; Henley, R.W. Advances in the understanding of epithermal gold-silver deposits, with special reference to the western United States. In The Geology of Gold Deposits: The Perspective in 1988; Keays, R.R., Ramsay, W.R.H., Groves, D.I., Eds.; Economic Geology Monograph 6; Society of Economic Geologists: Yale, America, 1989; pp. 405–423. [Google Scholar]
  4. Tolstykh, N.D.; Vymazalova, A.; Petrova, E.A.; Stenin, N. The Gaching Au mineralization in the Maletoyvayam ore field, Kamchatka, Russia. In Geological Survey of Canada, Open File 8317, Proceedings of the 14th Biennial SGA Meeting, Quebéc, QC, Canada, 20–23 August 2017; Mercier-Langevin, P., Goutier, J., Dubé, B., Eds.; Society for Geology Applied to Mineral Deposits: Quebec, Canada, 2017; Volume 1, pp. 195–198. ISBN 978-2-9816898-0-1. [Google Scholar]
  5. Tolstykh, N.; Vymazalova, A.; Tuhy, M.; Shapovalova, M. Conditions of formation of Au-Se-Te mineralization in the Gaching ore occurrence (Maletoyvayam ore field), Kamchatka, Russia. Mineral. Mag. 2018, 82, 649–674. [Google Scholar] [CrossRef]
  6. White, N.C.; Hedenquist, J.W. Epithermal gold deposits: Styles, characteristics and exploration. Publ. SEG Newsl. 1995, 23, 9–13. [Google Scholar] [CrossRef]
  7. Hedenquist, J.W.; Arribas, R.A. Epithermal ore deposits: First-order features relevant to exploration and assessment. In Proceedings of the 14th SGA Biennial Meeting, Quebec City, QC, Canada, 20–23 August 2017; Volume 1, pp. 47–50. [Google Scholar]
  8. Tolstykh, N.; Palyanova, G.; Bobrova, O.; Sidorov, E. Mustard gold of the Gaching ore occurrence (Maletoyvayam deposit, Kamchatka, Russia). Minerals 2019, 9, 489. [Google Scholar] [CrossRef] [Green Version]
  9. Sidorov, E.G.; Borovikov, A.A.; Tolstykh, N.D.; Bukhanova, D.S.; Palyanova, G.A.; Chubarov, V.M. Gold mineralization at the Maletoyvayam Deposit (Koryak Highland, Russia) and physicochemical conditions of its formation. Minerals 2020, 10, 1093. [Google Scholar] [CrossRef]
  10. Tolstykh, N.D.; Bortnikov, N.S.; Shapovalova, M.O.; Shaparenko, E.O. The Role of Hydrocarbons in the Formation of Epithermal Gold–Silver Deposits in Kamchatka, Russia. Dokl. Earth Sci. 2022, 507, 994–1000. [Google Scholar] [CrossRef]
  11. Tuhý, M.; Vymazalová, A.; Tolstykh, N.; Plášil, J.; Laufek, F. Gold chalcogenides natural occurrence in Maletoyvayam (Kamchatka, Russia)—An experimental approach. In Proceedings of the 15th Biennial Meeting of SGA, Glasgow, UK, 27–30 August 2019. [Google Scholar]
  12. Palyanova, G.; Beliaeva, T.; Kokh, K.; Seryotkin, Y.; Moroz, T.; Tolstykh, N. Characterization of synthetic and natural gold chalcogenides by electron microprobe analysis, X-ray powder diffraction and Raman spectroscopic methods. J. Raman Spectrosc. Methods 2022, 53, 1012–1022. [Google Scholar] [CrossRef]
  13. Tolstykh, N.D.; Tuhý, M.; Vymazalová, A.; Plášil, J.; Laufek, F.; Kasatkin, A.V.; Nestola, F.; Bobrova, O.V. Maletoyvayamite, Au3Se4Te6, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia. Mineral. Mag. 2020, 84, 117–123. [Google Scholar] [CrossRef]
  14. Tolstykh, N.D.; Tuhỳ, M.; Vymazalova, A.; Laufek, F.; Plášil, F. Gachingite, Au(Te1−xSex) 0.2 ≈ x ≤ 0.5, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia. Mineral. Mag. 2022, 86, 205–231. [Google Scholar] [CrossRef]
  15. Kasatkin, A.V.; Nestola, F.; Plášil, J.; Sejkora, J.; Vymazalová, A.; Škoda, R. Tolstykhite, Au3S4Te6, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia. Mineral. Mag. 2022, 87, 34–39. [Google Scholar] [CrossRef]
  16. Tolstykh, N.; Kasatkin, A.; Nestola, F.; Vymazalová, A.; Agakhanov, A.; Palyanova, G.; Korolyuk, V. Auroselenide, AuSe, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia. Mineral. Mag. 2022, 1–20. [Google Scholar] [CrossRef]
  17. Yuningsih, E.T.; Matsueda, H.; Rosana, M.F. Diagnostic Genesis Features of Au-Ag Selenide-Telluride Mineralization of Western Java Deposits. Indones. J. Geosci. 2016, 3, 67–76. [Google Scholar] [CrossRef] [Green Version]
  18. Hustor, D.L.; Sieb, S.H.; Suterb, G.F. Selenium theoretical and its importance to the study of ore genesis: The basis and its application to volcanic-hosted massive sulfide deposits using pixeprobe analysis. Nucl. Instrum. Methods Phys. Res. 1995, 104, 476–480. [Google Scholar] [CrossRef]
  19. Simon, G.; Kesler, S.E.; Essene, E.J. Phase Relations among Selenides, Sulfides, Tellurides, and Oxides: II. Applications to Selenide-Bearing Ore Deposits. Econ. Geol. 1997, 92, 468–484. [Google Scholar] [CrossRef]
  20. Slobodskoy, R.M. Organoelement Compounds in Magmatic and Ore-Forming Processes; Nauka: Novosibirsk, Russia, 1981. (In Russian) [Google Scholar]
  21. Tolstykh, N.; Bukhanova, D.; Shapovalova, M.; Borovokov, A.; Podlipsky, M. The gold mineralization of the Baranyevskoe Au-Ag epithermal deposit in Central Kamchatka. Minerals 2021, 11, 1225. [Google Scholar] [CrossRef]
  22. Tolstykh, N.D.; Shapovalova, M.O.; Shaparenko, E.O.; Bukhanova, D.S. The Role of Selenium and Hydrocarbons in Au-Ag Ore formation in the Rodnikovoe Low-Sulfidation (LS) Epithermal Deposit, Kamchatka Peninsula, Russia. Minerals 2022, 12, 1418. [Google Scholar] [CrossRef]
  23. Števko, M.; Sejkora, J.; Dolnícek, Z.; Škácha, P. Selenium-Rich Ag–Au Mineralization at the Kremnica Au–Ag Epithermal Deposit, Slovak Republic. Minerals 2018, 8, 572. [Google Scholar] [CrossRef] [Green Version]
  24. Stanley, C.J.; Criddle, A.J.; Lloyd, D. Precious and base metals selenide mineralization at Hope’s Nose, Torquay, Devon. Mineral. Mag. 1990, 54, 485–493. [Google Scholar] [CrossRef] [Green Version]
  25. Kolova, E.; Savva, N.; Zhuravkova, T.; Glukhov, A.; Palyanova, G. Au-Ag-S-Se-Cl-Br Mineralization at the Corrida Deposit (Russia) and Physicochemical Conditions of Ore Formation. Minerals 2021, 11, 144. [Google Scholar] [CrossRef]
  26. Bortnikov, N.S.; Savva, N.E.; Prokofiev, V.Y.; Kolova, E.E.; Dolomanova-Topol’, A.A.; Galyamov, A.L.; Murashov, K.Y. Epithermal Au-Ag-Se-Te deposits of the Chukchi Peninsula (Arctic Zone of Russia): Metallogeny, mineral assemblages, and fluid regime. Russ. Geol. Geophys. 2022, 63, 435–457. [Google Scholar] [CrossRef]
  27. Kirezidi, S.V. Geochemistry of selenium and tellurium in the ores of the Kochbulak deposit. Geol. Miner. Probl. Geoecol. Bashkortostan Ural. Adjac. Areas. 2018, 12, 249–255. (In Russian) [Google Scholar]
  28. Kuzhuget, R.V.; Zaykov, V.V.; Ankusheva, N.N. Au-Se-Te Mineralization of the Aldan-Maadyr Gold-Ore Cluster (Western Tuva). Geosph. Res. 2021, 1, 18–32. (In Russian) [Google Scholar] [CrossRef]
  29. Wiegers, G.A. Electronic and Ionic Conduction of Solid Solutions Ag2−xAuxSe (0 ≤ x ≤ 0.5). J. Less-Common Met. 1976, 48, 269–283. [Google Scholar] [CrossRef]
  30. Echmaeva, E.A.; Osadchii, E.G. Determination of the Thermodynamic Properties of Compounds in the Ag–Au–Se and Ag–Au–Te Systems by the EMF Method. Geol. Ore Depos. 2009, 51, 247–258. [Google Scholar] [CrossRef]
  31. Savva, N.E.; Pal’yanova, G.A. Genesis of gold and silver sulfides at the Ulakhan deposit (northeastern Russia). Russ. Geol. Geophys. 2007, 48, 799–810. [Google Scholar] [CrossRef]
  32. Bindi, L.; Pingitore, N.E. On the symmetry and crystal structure of aguilarite, Ag4SeS. Mineral. Mag. 2013, 77, 21–31. [Google Scholar] [CrossRef]
  33. Pal’yanova, G.A.; Chudnenko, K.V.; Zhuravkova, T.V. Thermodynamic properties of solid solutions in the system Ag2S–Ag2Se. Thermochim. Acta 2014, 575, 90–96. [Google Scholar] [CrossRef]
  34. Seryotkin, Y.V.; Pal’yanova, G.A.; Savva, N.E. Sulfur-selenium isomorphous substitution and morphotropic transition in the Ag3Au(SeS)2. Russ. Geol. Geophys. 2013, 54, 841–848. [Google Scholar] [CrossRef]
  35. Palyanova, G.A.; Seryotkin, Y.V.; Bakakin, V.V.; Kokh, K.A. Sulfureselenium isomorphous substitution in the AgAu(S,Se) series. J. Alloys Compd. 2016, 664, 385–391. [Google Scholar] [CrossRef]
  36. Ghosh, G.; Sharma, R.C.; Li, D.T.; Chang, Y. The Se-Te (Selenium-Tellurium) system. J. Phase Equilibria 1994, 15, 213–224. [Google Scholar] [CrossRef]
  37. Plotinskaya, O.Y.; Kovalenker, V.A.; Seltmann, R.; Stanley, C.J. Te and Se mineralogy of the high-sulfidation Kochbulak and Kairagach epithermal gold telluride deposits (Kurama Ridge, Middle Tien Shan, Uzbekistan). Mineral. Petrol. 2006, 87, 187–207. [Google Scholar] [CrossRef]
  38. Zhu, T.; Su, X.; Zhang, Q.; Tang, X. Structural transformation and thermoelectric performance in Ag2Te1−xSex solid solution. J. Alloys Compd. 2021, 871, 159507. [Google Scholar] [CrossRef]
  39. Palyanova, G.A.; Tolstykh, N.D.; Zinina, V.Y.; Kokh, K.A.; Seryotkin, Y.V.; Bortnikov, N.S. Synthetic Gold Chalcogenides in the Au–Te–Se–S System and Their Natural Analogs. Dokl. Earth Sci. 2019, 487, 929–934. [Google Scholar] [CrossRef]
  40. Cabri, L.J. Phase relations in the Au-Ag-Te system and their mineralogical significance. Econ. Geol. 1965, 60, 1569–1605. [Google Scholar] [CrossRef]
  41. Xu, W.; Zhao, J.; Brugger, J.; Chen, G.; Pring, A. Mechanism of mineral transformations in krennerite, Au3AgTe8, under hydrothermal conditions. Am. Mineral. 2013, 98, 2086–2095. [Google Scholar] [CrossRef]
  42. Xia, F.; Brugger, J.; Chen, G.; Ngothai, Y.; O’Neill, B.; Putnis, A.; Pring, A. Mechanism and kinetics of pseudomorphic mineral replacement reactions: A case study of the replacement of pentlandite by violarite. Geochim. Cosmochim. Acta 2009, 73, 1945–1969. [Google Scholar] [CrossRef]
  43. Pažout, R.; Srein, V.; Korbelova, Z. An unusual Ni-Sb-Ag-Au association of ullmannite, allargentum, Au-rich silver and Au-bearing dyscrasite from Oselske pasmo ‘silver’ Loge of Kutna Hora Pb-Zn-Ag ore district (Czech Republic). J. Geosci. 2018, 62, 247–252. [Google Scholar] [CrossRef] [Green Version]
Minerals 13 00420 g001 550
Figure 1. Location of the Kamchatka Peninsula in the Russian far east (a); geographical position of the Maletoyvayam deposit on the Kamchatka Peninsula (b); simplified geological map of the Vetrovayam volcano-tectonic structure, showing the Gaching ore occurence within the Maletoyvayam deposit (c).
Figure 1. Location of the Kamchatka Peninsula in the Russian far east (a); geographical position of the Maletoyvayam deposit on the Kamchatka Peninsula (b); simplified geological map of the Vetrovayam volcano-tectonic structure, showing the Gaching ore occurence within the Maletoyvayam deposit (c).
Minerals 13 00420 g001
Minerals 13 00420 g002 550
Figure 2. Compositions of Au-S-Se-Te minerals from the Maletoyvayam deposit in the systems (Se + S)-Au-Te (a) and S-Se-Te (b).
Figure 2. Compositions of Au-S-Se-Te minerals from the Maletoyvayam deposit in the systems (Se + S)-Au-Te (a) and S-Se-Te (b).
Minerals 13 00420 g002
Minerals 13 00420 g003 550
Figure 3. SEM back-scattered images of individual grains of tolstykhite Au3Te6S4 (Tls) (a), Tls – Mty solid solutions (b–d) and maletoyvayamite Au3Te6Se4 (Mty) (e,f) in intergrowths with Fe-Sb oxides (e), with calaverite AuTe2 (Clv) and Au-Sb-Fe oxide (e), with native gold (Au) (f), and unnamed phase AuTe2Se (e,f). Sample reference number is at the lower right corner of the images. Black dots with numbers correspond to analytical points (spectrum) in Table 1.
Figure 3. SEM back-scattered images of individual grains of tolstykhite Au3Te6S4 (Tls) (a), Tls – Mty solid solutions (b–d) and maletoyvayamite Au3Te6Se4 (Mty) (e,f) in intergrowths with Fe-Sb oxides (e), with calaverite AuTe2 (Clv) and Au-Sb-Fe oxide (e), with native gold (Au) (f), and unnamed phase AuTe2Se (e,f). Sample reference number is at the lower right corner of the images. Black dots with numbers correspond to analytical points (spectrum) in Table 1.
Minerals 13 00420 g003
Minerals 13 00420 g004 550
Figure 4. SEM back-scatter images of Te-Se solid solution members as separate grains (a), inclusions and intergrowths with goldfieldite (Gf) (b–f), and Au chalcogenide: tolstykhite (Tls) (d,e) and maletoyvayamite (Mty) (f). Sample reference number is at the lower right corner of the images. Black dots with numbers correspond to analytical points (spectrum) in Table 2.
Figure 4. SEM back-scatter images of Te-Se solid solution members as separate grains (a), inclusions and intergrowths with goldfieldite (Gf) (b–f), and Au chalcogenide: tolstykhite (Tls) (d,e) and maletoyvayamite (Mty) (f). Sample reference number is at the lower right corner of the images. Black dots with numbers correspond to analytical points (spectrum) in Table 2.
Minerals 13 00420 g004
Minerals 13 00420 g005 550
Figure 5. SEM back-scatter images of discrete calaverite (Clv) grains (a), intergrown with maletoyvayamite (Mty), tolstykhite (Tls), and goldfieldite (Gf) (b,c); calaverite grains, partially (d,e) or completely (f) replaced by Au-Fe-Sb(As) oxide. The numbers on samples and points with the number of the spectrum correspond to the analyses shown in Table 3.
Figure 5. SEM back-scatter images of discrete calaverite (Clv) grains (a), intergrown with maletoyvayamite (Mty), tolstykhite (Tls), and goldfieldite (Gf) (b,c); calaverite grains, partially (d,e) or completely (f) replaced by Au-Fe-Sb(As) oxide. The numbers on samples and points with the number of the spectrum correspond to the analyses shown in Table 3.
Minerals 13 00420 g005
Minerals 13 00420 g006 550
Figure 6. Reflected light. Textural features and morphology of grains of auroselenide (AuSe) (a–e), and gachingite (Gcg) (f), in association with minerals of the maletoyvaymite-tolstikhite (Mty) series, mostly replacing native gold (Au), as well as discrete inclusions.
Figure 6. Reflected light. Textural features and morphology of grains of auroselenide (AuSe) (a–e), and gachingite (Gcg) (f), in association with minerals of the maletoyvaymite-tolstikhite (Mty) series, mostly replacing native gold (Au), as well as discrete inclusions.
Minerals 13 00420 g006
Minerals 13 00420 g009 550
Figure 9. Ag-bearing microparagenesises in reflected light (a–c) and SEM back-scatter images (d–f). Miargyrite (May) and petrovskaite (Pvk) occur as rims around gold (Au) grains (a,d), intergrowths of gold with uytenbogaardtite (Uyt) (b,e), and tolstykhite (Tls), intermixed with unnamed phases (Ag,Au)9(S,Se)2Te3 and (Ag,Au)9(S,Se)3Te5. The reference number on samples, as well as the marked points, correspond to the analyses in Table 7.
Figure 9. Ag-bearing microparagenesises in reflected light (a–c) and SEM back-scatter images (d–f). Miargyrite (May) and petrovskaite (Pvk) occur as rims around gold (Au) grains (a,d), intergrowths of gold with uytenbogaardtite (Uyt) (b,e), and tolstykhite (Tls), intermixed with unnamed phases (Ag,Au)9(S,Se)2Te3 and (Ag,Au)9(S,Se)3Te5. The reference number on samples, as well as the marked points, correspond to the analyses in Table 7.
Minerals 13 00420 g009
Minerals 13 00420 g010 550
Figure 10. Composition of petrovskaite AuAgS, uytenbogaardtite Ag3AuS2, fischesserite Ag3AuSe2 (a), and Au-bearing miargyrite (Ag,Au)(Sb,As)S2 (b).
Figure 10. Composition of petrovskaite AuAgS, uytenbogaardtite Ag3AuS2, fischesserite Ag3AuSe2 (a), and Au-bearing miargyrite (Ag,Au)(Sb,As)S2 (b).
Minerals 13 00420 g010
Minerals 13 00420 g011 550
Figure 11. Compositions of maletoyvayamite-tolstykhite solid solution, occurring in the Ag-bearing association (MG-63) in (Se + S) – Au – Te (a), and S – Se – Te systems (b), compared to those in the Ag-poor association (Mt-8) in the Au – (Se + S) – Te and Se-S-Te systems.
Figure 11. Compositions of maletoyvayamite-tolstykhite solid solution, occurring in the Ag-bearing association (MG-63) in (Se + S) – Au – Te (a), and S – Se – Te systems (b), compared to those in the Ag-poor association (Mt-8) in the Au – (Se + S) – Te and Se-S-Te systems.
Minerals 13 00420 g011
Minerals 13 00420 g012 550
Figure 12. SEM back-scatter images of Au-complex oxides occurring intergrown with gold (a,c) and as an individual grain (b) from Ag-bearing associations. The reference number on samples, as well as the marked points, correspond to the analyses in Table 8.
Figure 12. SEM back-scatter images of Au-complex oxides occurring intergrown with gold (a,c) and as an individual grain (b) from Ag-bearing associations. The reference number on samples, as well as the marked points, correspond to the analyses in Table 8.
Minerals 13 00420 g012
Minerals 13 00420 g013 550
Figure 13. Compositional variations of Au, Fe, and Sb complex oxides, with minor Te, As, Se.
Figure 13. Compositional variations of Au, Fe, and Sb complex oxides, with minor Te, As, Se.
Minerals 13 00420 g013
Table
Table 1. Compositions (wt. %) of maletoyvayamite, tolstykhite, and associated minerals shown in Figure 3.
Table 1. Compositions (wt. %) of maletoyvayamite, tolstykhite, and associated minerals shown in Figure 3.
No.SampleSp.AuTeSeSTotalFormulas
1Mt-4_1-113237.1851.21.089.7399.19Au2.70(S4.35Se0.20)4.55Te5.75
2Mt-4_1-113337.0951.330.629.398.34Au2.76(S4.24Se0.11)4.35Te5.89
3Mt-4_1-514637.9150.353.937.4599.64Au2.88(S3.48Se0.74)4.22Te5.90
4Mt-4_1-514736.6250.674.547.0698.89Au2.81(S3.33Se0.87)4.20Te6.00
5Mt-4_1-614836.1947.599.944.0597.77Au2.95(S2.03Se2.02)4.05Te5.99
6Mt-4_1-615037.7250.963.957.73100.36Au2.82(S3.55Se0.74)4.29Te5.89
7Mt-4_2-416236.3347.3711.652.7398.08Au3.04(Se2.43S1.40)3.83Te6.12
8Mt-4_2-416335.9847.3612.012.5797.92Au3.02(Se2.52S1.33)3.85Te6.14
9G1-f_3-18295.86 97.08 *(Au0.98Ag0.02)1.00
10G1-f_3-18334.7246.3417.34 98.4Au3.00Se3.73Te6.17
11G1-f_3-18434.5446.2219.2 99.96Au2.92Se4.05Te6.03
12G1-f_3-18535.5246.1415.52 97.18Au0.98Te1.96Se1.06
13G1-f_2-110242.4353.511.5 97.44Au0.99(Te1.92Se0.09)2.01
14G1-f_2-110342.1753.721.63 97.52Au0.98(Te1.93Se0.09)2.02
15G1-f_2-19834.7846.218.24 99.22Au2.98Se3.90Te6.12
16G1-f_2-110033.7245.3217.68 96.72Au2.97Se3.88Te6.15
17G1-f_2-110433.0345.5318.02 96.58Au2.90Se3.94Te6.16
18G1-f_2-19636.346.7715.8 98.87Au0.98Te1.95Se1.07
*—Total includes 1.22 wt. % Ag. 1–6—tolstykhite; 7–8, 10–11, 15–17—maletoyvayamite; 9—gold; 12, 18—AuTe2Se, 13–14—calaverite; Sp.—spectrum number.
Table
Table 2. Compositions (wt. %) of native tellurium and Te-Se solid solutions, as well as their associated minerals, as shown in Figure 4.
Table 2. Compositions (wt. %) of native tellurium and Te-Se solid solutions, as well as their associated minerals, as shown in Figure 4.
No.SampleSp.FeCuAuAgSbTeAsSeSTotalFormulas
1D_4-41 53.14 45.770.4599.36Se0.57Te0.41S0.01
2D_4-42 52.25 45.850.3698.46Se0.58Te0.41S0.01
316h_1- 51 96.74 1.73 98.47Te0.97Se0.03
416h_1- 52 42.33 5.2814.776.488.9321.6799.46Cu11.36(Te1.97Se1.93As1.47Sb0.74)6.11S11,53
516h_2- 510.6843.15 0.410.5311.755.224.6423.3299.69(Cu11.39Fe0.20Ag0.06)11.65(Te1.54Sb1.45As1.17Se0.99)5.15S12.20
616h_2- 52 98.42 0.860.6599.93Te0.96S0.03Se0.01
716h_1- 21 38.56 50.65 4.217.06100.48Au2.94 (S3.30Se0.80)4.10Te5.96
816h_1- 22 89.61 11.06 100.67Te0.83Se0.17
916h_1- 230.4542.29 9.3615.661.635.7925.49100.67(Cu10.94Fe0.13)11.07(Te2.02Sb1.26Se1.21As0.36)4.85S13.08
10D_6-91 36.47 50.39 7.055.4799.38Au2.87 (S2.64Se1.38)4.02Te6.11
11D_6-92 79.96 19.560.2899.8Te0.71Se0.28S0.01
12D_6-930.243.36 17.27 6.62.7729.7799.97(Cu10.53Fe0.06)10.59(Sb2.19As1.36Se0.54)4.09S14.33
13D_6-94 32.63 43.13 122.0398.79Cu9.60(Te6.32Se0.24)6.56S12.85
14D_9-11 35.5 47.61 14.761.2399.1Au3.01 (Se3.12S0.64)3.76Te6.23
15D_9-12 35.47 47.08 15.411.0899.04Au3.01 (Se3.26S0.56)3.82Te6.17
16D_9-13 89.43 7.99 97.42Te0.87Se0.13
17D_9-140.3542.11 6.2313.76.198.6522.4999.72(Cu11.17Fe0.11)11.28(Se1.85Te1.81As1.39Sb0.86)5.91S11.82
1–3, 6, 8, 11, 16—Te-Se solid solutions; 4–5, 9, 13—goldfieldite; 7, 10—tolstykhite; 14–15—maletoyvayamite; 12—tetrahedrite; 17—Se-analogue of goldfieldite.
Table
Table 3. Compositions (wt. %) of calaverite AuTe2 and associated minerals, displayed in Figure 5.
Table 3. Compositions (wt. %) of calaverite AuTe2 and associated minerals, displayed in Figure 5.
No.SampleSpFeCuAuAgSbSOTotalFormulas
1D_5-101 43.81.01 0.36 102.31(Au0.95Ag0.04)0.99(Te1.86Se0.10S0.05)2.01
2D_5-102 42.061.09 98.46(Au0.96Ag0.05)1.01(Te1.89Se0.10)1.99
3D_5-103 43.150.9 0.26 101.15(Au0.95Ag0.04)0.99(Te1.87As0.10S0.04)2.01
416h_1-41 38.563.94 100.24(Au0.85Ag0.16)1.01(Te1.92Se0.07)1.99
516h_1-42 34.70 2.56 97.01Au2.91(Se2.71S1.32)4.03Te6.06 (Se2.71S1.32)
616h_2-21 42.980.93 100.85(Au0.96Ag0.04)1.00(Te1.89Se0.11)2.00
716h_2-227.280.6454.261.1112.55 12.8384.87(Au1.00Fe0.47Sb0.37As0.11Cu0.04Ag0.04Te0.04Se0.02)2.09O3.00
816h_2-237.80.7655.591.2213.44 15.5890.54(Au0.89Fe0.44Sb0.35As0.11Cu0.04Ag0.04Te0.03Se0.03)1.93O3.07
9D_7-61 44.27 0.54 101.33Au0.98(Te1.91S0.07Se0.04)2.02
10D_7-62 45.22 0.54 103.15Au0.98(Te1.88S0.07Se0.06)2.01
11D_7-633.32 61.810.759.94 13.1887.79(Au1.25Sb0.33Fe0.24As0.11Ag0.03)1.96O3.04
12D_5-61 44.04 0.45 99.29Au1.00(Te1.89S0.06Se0.05)2.00
13D_5-621.60 58.890.7713.950.5614.0891.39(Au1.08Sb0.41Fe0.10As0.08S0.06Te0.04Ag0.03)1.80O3.19
14D_5-631.75 57.981.1313.430.8712.8788.49(Au1.13Sb0.42Fe0.12S0.10As0.07Ag0.04Te0.03)1.91O3.09
Table
Table 4. Composition (wt. %) of auroselenide AuSe, shown in Figure 6.
Table 4. Composition (wt. %) of auroselenide AuSe, shown in Figure 6.
No.SampleAuTeSeSTotalFormulas
1d_3-869.401.9523.991.8897.22Au0.97(Se0.83S0.16Te0.04)1.03
2d_3-971.843.0221.832.0799.27Au0.99(Se0.77S0.18Te0.06)1.01
3d_6-1271.631.8723.472.5699.53Au0.96(Se0.79S0.21Te0.04)1.04
4d_2-468.030.6923.691.8594.77 *(Au0.97Ag0.01)0.98(Se0.84S0.16Te0.02)1.02
*—Total includes 0.51 wt. % Ag.
Table
Table 5. Compositions (wt. %) of gachingite Au(Te1–xSex) and related minerals. See Figure 7.
Table 5. Compositions (wt. %) of gachingite Au(Te1–xSex) and related minerals. See Figure 7.
No.SampleSp.AuTeSeTotalFormulas
1Mt13_3-4a1962.0627.867.8597.77Au1.00(Te0.69Se0.31)1.00
2Mt13_3-4a2062.2528.537.2998.07Au1.00(Te0.71Se0.29)1.00
3Mt13_3-4a2162.0127.957.4797.43Au1.00(Te0.70Se0.30)1.00
4Mt13_3-4a2261.3327.948.4297.69Au0.98(Te0.69Se0.33)1.02
5Mt13_3-4a2343.6153.631.6798.91Au1.00(Te1.90Se0.10)2.00
6Mt13_3-4a2435.8945.2714.6397.65 *Au3.04(Se3.09S0.97)4.06Te5.91
7Mt13_1-1_2-12562.8925.529.9898.39Au0.99(Te0.62Se0.39)1.01
8Mt13_1-1_2-12662.4725.549.5497.55Au0.99(Te0.63Se0.38)1.01
9Mt13_1-1_2-12762.8927.918.1198.91Au1.00(Te0.68Se0.32)1.00
10Mt13_1-1_2-12862.3728.947.3598.66Au0.99(Te0.71Se0.29)1.00
11Mt13_1-1_2-12962.3226.569.2198.09Au0.99(Te0.65Se0.36)1.01
12Mt13_1-1_2-13062.8724.879.9597.69Au1.00(Te0.61Se0.39)1.00
13Mt13_3-63662.6227.96.9197.43Au1.02(Te0.70Se0.28)0.98
14Mt13_3-63762.1327.87.7697.69Au1.00(Te0.69Se0.31)1.00
15Mt13_3-63862.4528.097.2597.79Au1.01(Te0.70Se0.29)0.99
16Mt13_3-63962.9528.137.698.68Au1.00(Te0.69Se0.30)0.99
*—Total includes 1.86 wt. % S. 1–4, 7–16—gachingite; 5—calaverite; 6—maletoyvayamite.
Table
Table 6. Compositions (wt. %) of Au(Se,Te) phases and their associated minerals included in native gold in Figure 8.
Table 6. Compositions (wt. %) of Au(Se,Te) phases and their associated minerals included in native gold in Figure 8.
No.SampleSp.AuTeSeSTotalFormulas
1D_11-3166.2617.9016.53 100.69Au0.98(Se0.61Te0.41)1.02
2D_11-3267.9816.3016.770.39101.44Au0.99(Se0.61Te0.37S0.03)1.01
3D_11-3367.1016.2715.900.5699.83Au0.99(Se0.59Te0.37S0.05)1.01
4D_11-3473.05 25.472.05100.57Au0.98(Se0.85S0.17)1.02
5D_11-3571.99 25.431.0298.44Au1.02(Se0.90S0.09)0.99
6D_11-3665.4618.041.410.3598.26Au1.00(Se0.55Te0.42S0.03)1.00
7D_11-3766.6517.4514.260.4097.76Au1.01(Se0.54Te0.41S0.04)0.99
8D_11-3866.2516.5815.550.3298.70Au1.00(Se0.59Te0.39S0.03)1.01
9D_11-3965.6417.0714.410.4897.60Au1.00(Se0.55Te0.40S0.05)1.00
10D_11-31065.5117.2515.760.5399.05Au0.97(Se0.58Te0.40S0.05)1.03
11D_11-31164.1417.5414.890.5997.16Au0.97(Se0.56Te0.41S0.05)1.02
12D_11-312 6.635.3438.07100.34Au2.91(S3.12Se1.02)4.14Te5.94
13D_11-313 4.968.8936.8599.86Au2.90(S2.40Se1.74)4.14Te5.96
14D_11-314 0.8417.1136.02101.56Au2.98(Se3.53S0.43)3.96Te6.07
15D_11-315 0.9317.4836.15101.78Au2.97(Se3.58S0.47)4.05Te5.98
16D_11-316 0.7916.983. 17101.64Au2.99(Se3.51S0.40)3.91Te6.10
17D_11-317 98.5199.79 *Au0.98Ag0.03
18D_11-318 96.8998.31 **Au0.97Ag0.03
*, **—1.21 and 1.42 wt. % Ag, respectively, included in the total. 1–3, 6–11—unnamed Au(Se,Te); 4–5—auroselenide; 12–13—tolstykhite; 14–15—maletoyvayamite; 17–18—gold.
Table
Table 7. Compositions (wt. %) of Ag-bearing minerals, shown in Figure 9, from the Maletoyvayam deposit.
Table 7. Compositions (wt. %) of Ag-bearing minerals, shown in Figure 9, from the Maletoyvayam deposit.
No.SiteSp.AuAgSbTeAsSeSTotalFormulas
1MG-63_10-5198.12 98.12Au1.00
2MG-63_10-52100.20 100.2Au1.00
3MG-63_10-5328.2418.1734.12 0.91 19.29100.73(Ag0.56Au0.48)1.04(Sb0.93As0.04)0.97S2.00
4MG-63_10-5428.4218.6925.11 8.22 20.37100.81(Ag0.55Au0.45)1.00(Sb0.65As0.35)1.00S2.00
5MG-63_10-5527.7620.2421.37 10.24 20.0899.69(Ag0.59Au0.44)1.03(Sb0.55As0.43)0.98S1.98
6MG-63_10-5627.6519.0325.48 8.47 20.28100.91(Ag0.55Au0.44)0.99(Sb0.66As0.36)1.02S1.99
7MG-63_10-5723.1819.6333.53 1.85 19.9798.16(Ag0.60Au0.39)0.99(Sb0.90As0.08)0.98S2.04
8MG-63_10-5852.1236.95 10.3599.42Ag1.10Au0.85S1.04
9MG-63_10-5952.7438.01 10.13100.88Ag1.13Au0.86S1.01
10MG-63_10-51051.5936.36 1.4510.0999.49Ag1.08Au0.84(S1.01Se0.06)1.07
11MG-63_10-711100.51 100.51Au1.00
12MG-63_10-712100.52 100.52Au1.00
13MG-63_10-71336.6952.25 10.9299.86Ag2.87Au1.11S2.02
14MG-63_10-71431.2357.05 2.179.4799.92Ag3.14Au0.94(S1.75Se0.16)1.91
15MG-63_10-71528.2957.89 0.7310.1297.03Ag3.20Au0.86(S1.88Se0.06)1.94
16MG-63_10-71630.2956.66 11.4898.43Ag3.04Au0.89S2.07
17MG-63_10-84439.19 50.58 2.617.4599.83Au3.00(S3.51Se0.50)4.01Te5.99
18MG-63_10-85138.58 49.46 1.997.6597.68Au3.01(S3.66Se0.39)4.05Te5.95
19MG-63_10-85238.91 49.81 2.337.4898.53Au3.02(S3.57Se0.45)4.02Te5.97
20MG-63_10-84938.16 50.08 2.557.398.09Au2.98(S3.50Se0.50)4.00Te6.03
21MG-63_10-84530.5742.24 22.80 1.053.62100.28(Ag6.44Au2.55)8.99(S1.86Se0.22)2.08Te2.94
22MG-63_10-85030.4341.94 23.00 1.093.68100.14(Ag6.39Au2.54)8.93(S1.89Se0.23)2.12Te2.96
23MG-63_10-84631.2629.65 31.21 1.404.0097.52(Ag5.69Au3.29)8.98(S2.58Se0.37)2.95Te5.07
1–2, 11–12—gold; 3–7—miargyrite (Ag,Au)(Sb,As)S2; 8–10—petrovskaite AgAuS; 13–16—uytenbogaardtite Ag3AuS2; 17–20—tolstykhite Au3S4Te6; 21–23 13–16—unnamed phases from the Ag-Au-Te-S-Se system: (Ag,Au)9(S,Se)2Te3 and (Ag,Au)9(S,Se)3Te5; 17–20—tolstykhite Au3S4Te6; 21–23—unnamed phases from the Ag-Au-Te-S system: (Ag,Au)9(S,Se)2Te3 and (Ag,Au)9(S,Se)3Te5.
Table
Table 8. Compositions (wt. %) of Au(Ag)-Fe-Sb oxides, shown in Figure 12, from Ag-bearing associations.
Table 8. Compositions (wt. %) of Au(Ag)-Fe-Sb oxides, shown in Figure 12, from Ag-bearing associations.
SampleSp.FeAuAgSbTeAsOTotalFormulas
MG-63_10-148.2562.89 9.89 1.5914.9589.32(Au1.37Fe0.55Sb0.07As0.04Te0.03)2.06O2.95
MG-63_10-368.7877.16 2.510.960.7513.4894.86(Au0.62Fe0.52Sb0.04As0.03Te0.02)1.23O3.76
MG-63_10-3816.6669.39 3.001.461.3734.29109.51(Au0.80Fe0.59Sb0.31As0.08)1.78O3.22
MG-63_10-116711.0953.47 12.65 2.1217.4485.68(Au0.77Fe0.60Sb0.31As0.09Ag0.03)1.80O3.21
MG-63_10-117112.0054.291.0513.74 2.2918.4189.78(Au0.85Fe0.57Sb0.29As0.08Ag0.03)1.82O3.19
MG-63_10-117210.7557.140.9112.06 1.9917.3789.47(Au1.46Fe0.57As0.07)2.10O2.90
MG-63_10-11737.9872.05 1.3011.6484.99(Au1.35Fe0.55As0.07Sb0.03)2.00O3.01
MG-63_10-11748.2171.76 0.96 1.3712.9787.06(Au1.46Fe0.54As0.07Sb0.03)2.10O2.90
MG-63_10-11757.8775.31 0.97 1.3712.1489.79(Au1.06Fe0.49Sb0.27As0.07)1.89O3.11
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Tolstykh, N.; Shapovalova, M.; Podlipsky, M. Au-Ag-Se-Te-S Mineralization in the Maletoyvayam High-Sulfidation Epithermal Deposit, Kamchatka Peninsula. Minerals 2023, 13, 420. https://doi.org/10.3390/min13030420

AMA Style

Tolstykh N, Shapovalova M, Podlipsky M. Au-Ag-Se-Te-S Mineralization in the Maletoyvayam High-Sulfidation Epithermal Deposit, Kamchatka Peninsula. Minerals. 2023; 13(3):420. https://doi.org/10.3390/min13030420

Chicago/Turabian Style

Tolstykh, Nadezhda, Maria Shapovalova, and Maksim Podlipsky. 2023. "Au-Ag-Se-Te-S Mineralization in the Maletoyvayam High-Sulfidation Epithermal Deposit, Kamchatka Peninsula" Minerals 13, no. 3: 420. https://doi.org/10.3390/min13030420

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop