Next Article in Journal
Pollution Characteristics, Distribution and Ecological Risk of Potentially Toxic Elements in Soils from an Abandoned Coal Mine Area in Southwestern China
Previous Article in Journal
The Effect of Hydrodynamic Conditions on the Selective Flotation of Fully Liberated Low Grade Copper-Nickel Ore
Previous Article in Special Issue
Re-Os Isotope Systematics of Sulfides in Chromitites and Host Lherzolites of the Andaman Ophiolite, India
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 11
Issue 3
10.3390/min11030329
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

Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence

by
Kreshimir N. Malitch
1,*,
Inna Yu. Badanina
1,
Elena A. Belousova
2,
Valery V. Murzin
1 and
Tatiana A. Velivetskaya
3
1
Zavaritsky Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, Vonsovsky 15, 620016 Ekaterinburg, Russia
2
Centre of Excellence for Core to Crust Fluid Systems, Department of Earth and Environmental Sciences, Macquarie University, Sydney, NSW 2109, Australia
3
Far East Geological Institute, Far Eastern Branch of the Russian Academy of Sciences, Prospect 100-letya Vladivostoku 159, 690022 Vladivostok, Russia
*
Author to whom correspondence should be addressed.
Minerals 2021, 11(3), 329; https://doi.org/10.3390/min11030329
Submission received: 31 December 2020 / Revised: 24 February 2021 / Accepted: 17 March 2021 / Published: 22 March 2021
(This article belongs to the Special Issue New Insights into Composition of the Earth’s Mantle Deduced from Osmium Isotope Data in Os-Rich Alloys, Sulfides, and Chromite)
Browse Figures
Versions Notes

Abstract

:
This study presents new compositional and S-Os isotope data for primary Ru-Os sulfides within a platinum-group mineral (PGM) assemblage from placer deposits associated with the Verkh-Neivinsk massif, which is part of the mantle ophiolite association of Middle Urals (Russia). The primary nature of Ru-Os sulfides represented by laurite (RuS2)–erlichmanite (OsS2) series is supported by occurrence of euhedral inclusions of high-Mg olivine (Fo92–94) that fall within the compositional range of mantle (primitive) olivine (Fo 88–93). The sulfur isotope signatures of Ru-Os sulfides reveal a range of δ34S values from 0.3 to 3.3‰, with a mean of 2.05‰ and a standard deviation of 0.86‰ (n = 18), implying that the sulfur derived from a subchondritic source. A range of sub-chondritic initial 187Os/188Os values defined for Ru-Os sulfides (0.1173–0.1278) are clearly indicative of derivation from a sub-chondritic source. Re-depletion (TRD) ages of the Verkh-Neivinsk Ru-Os sulfides are consistent with prolonged melt-extraction processes and likely multi-stage evolution of highly siderophile elements (HSE) within the upper mantle. A single radiogenic 187Os/188Os value of 0.13459 ± 0.00002 determined in the erlichmanite is indicative of a supra-chondritic source of HSE. This feature can be interpreted as evidence of a radiogenic crustal component associated with a subduction event or as an indication of an enriched mantle source. The mineralogical and Os-isotope data point to a high-temperature origin of the studied PGM and two contrasting sources for HSE in Ru-Os sulfides of the Verkh-Neivinsk massif.

1. Introduction

Dominance of Ru-Os-Ir minerals over other platinum-group minerals (PGM) is considered a typical feature of podiform chromitites within the residual mantle in ophiolite-type dunite-harzburgite massifs worldwide [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15], among others. According to equilibrium phase diagrams, experimental results, and empirical data, Ru-Os–Ir alloys and Ru-Os sulfides are considered to be formed during the very early stages of magmatic differentiation, under low fugacity of sulfur, and high-temperature conditions [11,16,17,18,19,20,21,22,23]. Ru–Os sulfides from podiform chromitites within the oceanic mantle are particularly important because they are believed to preserve the isotopic values of the sources of highly siderophile elements (HSE) and sulfur from which these Ru-Os sulfides were formed/crystallized. Usefulness of S-isotopic information collected on Ru-Os sulfides derived from the oceanic mantle has been outlined by Hattori et al. [24], whereas Os isotope data gained for Ru-Os-Ir alloys and sulfides from the dunite-harzburgite massifs worldwide [12,25,26,27,28,29,30,31,32,33,34,35,36], among others, and Ru-Os-Ir alloys from placer deposits [37,38,39,40,41,42,43] shed new insights on the multi-stage evolution history of PGM in mantle-derived ultramafic complexes. Among different points of view on the formation of chromitites and PGM, a significant place is given to the osmium isotope data of PGM, which are discussed in the framework of (i) the long-term evolution of the upper mantle, (ii) the heterogeneity of mantle derivatives, and (iii) the interaction of various sources of PGE/HSE [12,44].
The Urals is a unique structure of the Earth, where the main types of ultramafic massifs formed in various geodynamic settings (continental, oceanic, and island-arc) are found. More than a century of studies of the oceanic dunite-harzburgite massifs of the Urals have shown that both the rocks and the associated types of chromite and PGM were formed in a wide time interval, experienced complex processes of high-temperature plastic deformations, along with dynamic recrystallization; at the same time, they also experienced destruction and amalgamation of individual blocks into larger massifs (complexes).
The Verkh-Nevinsk massif, a typical representative of the mantle ophiolitic association at the Middle Urals (Figure 1a), is characterized by primary and secondary PGM assemblages [45]. The primary PGM assemblage, which is dominated by Ru-Os-Ir alloys over Ru-Os sulfides, Pt-Fe alloys, and other PGM, are typical for chromitites, whereas both the primary and secondary PGM assemblages are found in placer deposits of the Vostochny Shishim River draining different lithological units of the Verkh-Neivinsk massif (Figure 2). Secondary PGM assemblages usually form the outer part of polyphase aggregates, which contain a core composed of a Ru-Os-Ir alloy, rimmed by secondary As-bearing laurite, irarsite (IrAsS), and tolovkite (IrSbS).
Particularities of their chemistry and the physicochemical conditions of formation of Ru-Os-Ir alloys are given elsewhere [22,46,47,48]. The previously collected Os-isotope data for primary Ru-Os-Ir alloys and Ru-Os sulfides from the Verkh-Nevinsk massif revealed a wide range of sub-chondritic 187Os/188Os values (from 0.1162 to 0.1346 [49,50]), whereas first S-isotope data for Ru-Os sulfides showed a restricted range of δ34S values (from 0.2 to 2.3‰ [51]). Both datasets were interpreted as being consistent with a deep-seated source of highly siderophile elements (HSE) and sulfur.
To gain further insight into the origin of Ru-Os sulfides, we have carried out a combined mineralogical and isotope study of laurite (RuS2)–erlichmanite (OsS2) series within a primary PGM assemblage from placer deposit linked to the Verkh-Neivinsk massif. Here, we consider new S-isotope data for 18 Ru-Os sulfide grains, for which Os-isotope data were previously collected on the same spots within PGM samples (16 samples from Reference [50], and 2 new samples). These data are compared with S-isotope data for Ru-Os sulfides [24,51] and Os-isotope data for ultramafic rocks, Ru-Os sulfides and Ru-Os-Ir alloys [49,50,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67]. Information on genetic features of PGM formation is supplemented by compositional data of solid inclusions typical of the studied Ru-Os sulfides. We integrate an application of electron microprobe analyses of Ru-Os sulfides and solid inclusions within PGM, Re-Os LA-MC-ICP-MS analyses of Ru-Os sulfides and coexistent Os-rich alloys, and S-isotope LA-ICP-MS analyses of Ru-Os sulfides, aiming at (i) evaluating compositional signatures of different morphological types of Ru-Os sulfides, and (ii) constraining the sources of HSE and sulfur within this fragment of the Uralian mantle. This study is part of a larger attempt to elucidate the mantle versus crustal origin of HSE/S in oceanic and subcontinental mantle settings [12,22,24,25,26,34,35,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67], among others.

2. Geological Characteristics of Samples

The Verkh-Neivinsk massif is situated at the junction of the Tagil Megasynclinorium and the East Ural Uplift in the zone of the Serov–Mauk deep-seated fault (Figure 1b). It is composed of two complexes: dunite-harzburgite complex that comprises the inner part of the massif and dunite-clinopyroxenite-gabbro complex developed at the periphery (Figure 2). The former complex is attributed to the Late Ordovician–Early Silurian (O3–S1), whereas the latter has Middle Silurian–Middle Devonian (S2–D2) age [45]. Sixty-eight occurrences and small deposits of chromite ores were discovered in lithological units of both complexes. The main occurrences of noble metals (native gold and PGM) are related to the placer deposits of modern and ancient river valleys. Representative collection of 685 grains of Ru-Os-Ir minerals in a size range from 0.1 to 3 mm was sampled from a gold production concentrate during prospecting of the Tertiary and Quaternary sediments of the Vostochny Shishim River that are confined to the southern part of the Verkh-Neivinsk massif (Figure 2). According to Badanina et al. [47], PGM grains are mainly represented by sub-euhedral and euhedral crystals with subordinate amount of crystal aggregates, among which Ru-Os-Ir alloys (83.5%) prevail over Ru-Os sulfides (15.3%) and Pt-Fe alloys (1.2%). In terms of morphology, Ru-Os-Ir alloys are characterized by well-preserved combinations of basal plane, hexagonal prism, and hexagonal dipyramid, whereas Ru-Os sulfides and Pt-Fe alloys have rough, sometimes shallow surfaces of crystal grains and crystal aggregates. Majority of primary PGM are monophasic. The remaining polyminerallic grains are dominated by IPGE alloys (Os, Ir, and Ru), with minor amounts of one or several other PGM inclusions, including laurite RuS2, kashinite Ir2S3, cuprorhodsite CuIr2S4, cooperite PtS, Pt-Fe alloys, irarsite IrAsS, hollingworthite RhAsS, keithconnite Pd20Te7, and ruthenarsenite RuAs [47]. The PGM grains analyzed in this study are nuggets (crystals and aggregates) that fall within a size range between 0.5 and 1.5 mm.

3. Analytical Techniques

Microprobe analyses of Ru-Os sulfides and mineral inclusions were carried out with a CAMECA SX-100 equipped with five WDS spectrometers and a Bruker energy dispersive spectrometer system at Common Use Center “Geoanalyst” of Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences (Ekaterinburg, Russia). Quantitative WDS analyses were performed at 25 kV accelerating voltage and 20 nA sample current, with a beam diameter of about 1 µm. The following X-ray lines and standards have been used: RuLα, RhLα, PdLβ, OsMα, IrLα, PtLα, NiKα (all native element standards), FeKα, CuKα, SKα (all chalcopyrite), and AsLα (sperrylite). Corrections were performed for the interferences involving Ru-Rh, Ru-Pd, and Ir-Cu. All elements but Os, Ir, Ru, Rh, Fe, and S were found to be below the statistically reliable detection limits under the analytical conditions. Additional details of the analytical procedures used are described in Badanina et al. [47].
Twenty-six in-situ Os-isotope analyses of Ru-Os sulfides and coexistent Ru-Os-Ir alloys were carried out at the Geochemical Analysis Unit at the CCFS/GEMOC laboratories (Macquarie University, Sydney, Australia) using analytical methods reported in other publications [32,34,64,67]. These analyses used a Nu Plasma Multi-collector ICP-MS attached to a New Wave/Merchantek UP 213 laser microprobe. Ablation was carried out with a frequency of 4 Hz, energies of 1–2 mJ/pulse, and a spot size of 15 μm. A standard NiS bead (PGE-A) with 199 ppm Os [68] and 187Os/188Os = 0.1064 [67], along with a natural Os alloy (i.e., Os1.0) from the Guli massif [69,70], were analyzed between PGM samples to monitor any drift in the Faraday cups. The overlap of 187Re on 187Os was corrected by measuring the 185Re peak and using 187Re/185Re = 1.6742. All the analyzed grains have 187Re/188Os lower than 0.005, thus ensuring that the isobaric interference of 187Re on 187Os was precisely corrected [31]. The data were collected using the Nu Plasma time-resolved software, which allows the selection of the most stable intervals of the signal for integration. For laurite with grain sizes between 50 and 1000 μm and Os average contents of ~10 at.%, a typical run duration of ~75 s was achieved with an average signal intensity of Os~7.8 V on the Faraday cups. This gives a precision for 187Os/188Os ranging from 2.1 × 10−5 to 9.2 × 10−5 (SE). The external reproducibility of 187Os/188Os for the PGE-A standard during the period of measurements was 0.00013 (2σ SD, n = 15) with a mean value of 0.10652. Repeated analyses of a natural crystal of native osmium, which has been used to check the validity of the LA MC ICP-MS measurements, yield 187Os/188Os = 0.12452 ± 0.00004 (2σ SD, n = 27). This perfectly matches two previously measured LA MC ICP-MS analyses (Neptune MC ICP-MS attached to a New Wave Compex-2 DUV 193 laser microprobe, Russian Geological Institute, St. Petersburg, Russia) for the same Os grain with 187Os/188Os ranging between 0.124546 ± 0.000007 and 0.124566 ± 0.000013. Rhenium-depletion model ages (TRD) and Re-Os model ages (TMA) were defined previously by other authors [71,72]. Rhenium-depletion model ages (TRD) are calculated using the equation TRD = (1/λ) × ln((((187Os/188Os)sample–(187Os/188Os)CHUR)/(187Re/188Os)CHUR) + 1), where λ represent a 187Re decay constant of 1.666 × 10−11 a−1 [73], whereas sample and CHUR parameters represent present-day values. The TRD in this study were calculated relative to an Enstatite Chondrite Reservoir (TECR) with 187Re/188Os = 0.421 ± 0.013 [74] and present-day 187Os/188Os = 0.1281 ± 0.0004. Alternative 187Os/188Os values for the present-day mantle, in widespread use for calculation of model ages, are 0.12736 [75], 0.1270 [71], and 0.1296 ± 0.0008 [76], where 187Re/188Os is taken as 0.40186 [71]. Calculations using the first two 187Os/188Os estimates would result in model ages that are approximately 0.15–0.2 Ga younger. If the 187Os/188Os value of primitive upper mantle (PUM) is used, the model ages of PGM are approximately 0.2 Ga older.
Eighteen S-isotope analyses were subsequently performed at the Laboratory of Stable Isotope within Common Use Center of the Far East Geological Institute, Far Eastern Branch of the Russian Academy of Sciences (Vladivostok, Russia). In situ S-isotope data were collected on the same spots within Ru-Os sulfide grains, for which Os-isotopic composition was analyzed previously. Sample preparation for mass spectrometric isotope analysis of sulfur was carried out using a femtosecond laser ablation system, NWR Femto, in combination with a reactor for sulfide aerosol conversion into SF6 gas, a cryogenic and chromatographic purification system, and an isotope ratio mass spectrometer (FsLA-GC-IRMS) [77,78]. Isotope ratios of sulfur were measured using a MAT-253 mass spectrometer (Thermo Fisher Scientific, Germany) equipped with a Faraday cup for simultaneous measurements of the ion currents at m/z 127 (32SF5 +) and 129 (34SF5 +). The measurements were carried out relative to the laboratory working standard, calibrated to the international standards IAEA-S-1, IAEA-S-2, and IAEA-S-3. The sulfur isotope composition in the sample was calculated as δ34S = ((34S/32S)sample-(34S/32S)standard)/(34S/32S)standard × 103 and expressed in ‰ with respect to reference standard VCDT (Vienna Canyon Diablo Troilite). Average accuracy of δ34S analyses was better than 0.2‰ (2σ). Further details of analytical methods are presented elsewhere [77,78].

4. Results

4.1. Compositional Characteristics of Ru-Os Sulfides, Os-Rich Alloys, and High-Magnesian Olivine from Primary PGM Assemblage

Typical morphological features, characteristic textures of Ru-Os sulfides, formed by single relatively large grains and small inclusions in Os-Ir alloy grains (termed as type 1 and 2, respectively), and associated minerals are illustrated in Figure 3, Figure 4 and Figure 5. Representative results of 48 electron microprobe WDS analyses of Ru-Os sulfides and associated Os-rich alloys (out of a total of 219 analyses) and 9 electron microprobe WDS analyses of high-Mg olivine inclusions are shown in Table 1, Table 2 and Table 3 and Figure 6.
Two morphological groups of Ru-Os sulfides were distinguished. The first one (type 1) includes single grains ranging in size from 1.0 to 1.5 mm (Figure 3a–e). They show a complete compositional spectrum, from laurite RuS2 to erlichmanite OsS2 (Figure 7a, Ru # varies from 12 to 89). In addition to Ru, Os, and S, these minerals have significant contents of Ir (3.32–10.71 wt.%) and negligible abundances of Fe, Ni, and Rh, which vary within 0.17–0.40, b.d.l.–0.23, and b.d.l.–0.39 wt.%, respectively (Table 1). Ru-Os sulfides contain inclusions of iridian osmium (Os, Ir) that can be as large as 30 μm across (Figure 3c,f and Table 2, analysis 10), and high-magnesian olivine (Fo92–94) with grain sizes from 5 to 40 μm (Figure 4 and Figure 5, Table 3, analyses 2–9). Ru-Os sulfides of the second morphological group (type 2) represent mineral inclusions (with typical sizes of 30–80 microns) enclosed in Os-Ir-(Ru) alloys (Figure 6, Table 2, analyses 12, 14, 16). These inclusions have higher ruthenium content (Figure 7b, Ru # varies from 54 to 100) and correspond to laurite (Table 2, analyses 11, 13, 15). Rare inclusions of high-magnesian olivine (Fo93) were also revealed in Os-Ir alloy (Figure 4a, Table 3, analysis 1).
Os-Ir-Ru alloys from the primary PGM assemblage of Verkh-Neivinsk are dominated by native osmium, ruthenium, and iridium (Figure 7c). The variation of osmium and ruthenium concentrations are due to the substitution by iridium in the solid solution of osmium (the trend of compositions along the horizontal axis Os-Ir in Figure 7c) or ruthenium (vertical trend of compositions towards Ru, Figure 7c).

4.2. Sulfur Isotope Data

The δ34S values in Ru-Os sulfides of both morphological types show a relatively narrow range from 0.3 to 3.3‰ (Table 4, Figure 8 and Figure 9), with a mean of 2.05‰ and a standard deviation of 0.86‰ (n = 18). The δ34S values in Ru–Os sulfides of type 1 have slightly narrower range from 0.3 to 2.8‰ (Table 4, Figure 10), with a mean of 1.82 ± 0.83‰ (n = 14). We note that the mean δ34S value for laurite (i.e., 1.64 ± 0.91‰, n = 9) corresponds, within the analytical error, to that of erlichmanite (2.16 ± 0.55‰, n = 5; Table 4, Figure 10). Laurite inclusions of type 2 are characterized by δ34S composition ranging from 1.5 to 3.3‰ (Table 4, Figure 10) and a slightly higher δ34S mean of 2.66 ± 0.73‰ (n = 4).

4.3. Osmium Isotope Data

The Os-isotope data for Ru-Os sulfides and associated Os-rich alloys are provided in Table 4 and Figure 8 and Figure 9. Solitary grains of laurite and erlichmanite of type 1 show a very wide range of 187Os/188Os values (between 0.11728 and 0.13459, and 187Re/188Os < 0.00009). 187Os/188Os values in laurite and erlichmanite vary from 0.11728 to 0.12503 and from 0.12061 to 0.13459, respectively (Table 4). Thus, in addition to sub-chondritic values (187Os/188Os < 0.1281), a supra-chondrite isotope composition of osmium was detected in erlichmanite (187Os/188Os = 0.13459 ± 0.00002). If the outliers with the most radiogenic 187Os/188Os values in erlichmanite grains are excluded (i.e., 0.12788 and 0.13459, respectively), the Os-isotope results identify a more restricted 187Os/188Os range for erlichmanite (0.12061–0.12261) of the first morphological type. Laurite inclusions typical of the second morphological type are characterized by a similar degree of Os-isotope variations (187Os/188Os from 0.11774 to 0.12506, Table 4, Figure 9) with that of type 1 laurites. We also note a similarity of the Os-isotopic compositions for coexisting laurite and Os-Ir-(Ru) alloys (Table 4, Figure 9a,b).
Due to very low 187Re/188Os values, the Re-Os model and Re-depletion ages (i.e., TMA and TRD [71,72]) of Ru-Os sulfides are identical. TRD ages for laurite of the first and second type, calculated relative to an Enstatite Chondrite Reservoir (ECR) model [74], display comparable variations (436–1523 and 432–1459 Ma respectively, Table 4), whereas erlichmanites are characterized by more moderate variations (TRD ages from 1059 to 778 Ma).

5. Discussion

The provenance of the investigated Ru-Os sulfide and Ru-Os-Ir alloy grains is obvious: the placer deposits display a close spatial association with the Verkh-Neivinsk dunite-harzburgite massif (Figure 2). The primary nature of Ru-Os sulfides of the first morphological type is supported by occurrence of euhedral inclusions of high-Mg olivine (Fo92–94) that fall within the compositional range of mantle (primitive) olivine (Fo 88–93) and also perfectly match the composition of olivine (with a pronounced peak between Fo93 and Fo94) in peridotite xenoliths from the mantle beneath Archean cratons [80,81,82]. The primary PGM from chromitites that form relatively small discordant bodies in residual dunites and harzburgites at Verkh-Neivinsk (unpublished data) share mineralogical and compositional characteristics with those of the detrital PGM. These chromitites are characterized by negatively sloped, chondrite-normalized platinum-group element (PGE) patterns [83], which is consistent with the preponderance of a rather limited variety of PGM of the IPGE group (i.e., dominated by laurite and Ru-Os-Ir alloy). Based on these lines of evidence, we suggest that the studied Ru-Os sulfides were derived from mantle residual rocks of the Verkh-Neivinsk massif, although the derivation of these PGM from the Moho-transition zone dunite-clinopyroxenite complex cannot be ruled out. Both options may be verified by distinct Ni concentrations in highly-magnesian olivine inclusions within the studied PGM. High Ni contents (0.33–0.42 wt.%) in all but one forsterite inclusions are consistent with a mantle origin of olivine, whereas moderate Ni abundances (0.14–0.17 wt.%) in forsterite within Os-rich laurite may indicate its derivation from different source rocks that form dunite-clinopyroxenite complex.
The composition of the laurite-erlichmanite series, plotted on the Os-Ir-Ru diagram (Figure 7a), shows common Os substitution for Ru (Ru# between 12 and 89), typical of mantle chromitites from Kempirsai and Rai-Iz (Urals), Kraubath, Eastern Alps, and Unst, Shetland Isles [5,9,11,84]. A high-temperature origin of euhedral inclusions of laurite type 2 in Os-Ir-(Ru) alloys are supported by recent experimental data [18,19,20,21] that quantitatively evaluated the effects of T and f(S2) for laurite + alloy mineral pairs. This is consistent with the presence of a ruthenium trend in Ru-Os-Ir alloys at Verkh-Neivinsk (Figure 7c), which is indicative of high temperature and pressure values that can only be reached under mantle conditions [85]. These integrated data present irrefutable evidence that Os-Ir-Ru alloys have formed at high T-P environments and that the observed chemical compositional variations represent primary features of the grains [26,40,42,70,85,86,87,88]. Thus, these refractory alloys are considered to be representative of depleted mantle material within the mantle sections of ophiolites.
The early formation of laurite and Os-Ir alloys at high T-P conditions implies that the original S- and Os-isotope composition of these PGM reflects the source region in the mantle at the time of their formation. The sulfur-isotope results of this study display a narrow range of δ34S values for single (individual) type 1 laurite grains ranging from 0.3 to 2.8, with a mean of 1.64‰ and a standard deviation of 0.91‰ (n = 9), which is within the analytical uncertainty with that of solitary erlichmanite grains (δ34S mean of 2.16 ± 0.55‰, n = 5) and laurite inclusions of type 2 (δ34S mean of 2.66 ± 0.73‰, n = 4, Figure 10). According to Thode et al. [89], the sulfur isotope composition of the Earth’s mantle is considered to be homogeneous with a mean δ34S of 0.0‰, a value indistinguishable from that of chondrites (δ34S = 0.04 ± 0.31‰, n = 24 [90,91]). Delta34S values beyond 0 ± 2‰ are considered to be a result of the mantle–crust interaction processes (denoting a contribution of crustal-derived sulfur) both at mantle conditions [92] and during formation of mantle magmas under crustal conditions [93]. The sulfur isotope composition of Ru-Os sulfides from the oceanic mantle was initially studied by Hattori et al. [24], who showed that Ru-Os sulfides from placer deposits in Borneo have a mean δ34S value of 1.16 ± 0.36‰, which is consistent with a mantle source of sulfur. In a subsequent investigation of solitary grains of Ru-Os sulfides at Verkh-Neivinsk (δ34S = 1.29 ± 0.65‰) [51], they appeared to be similar to that of Ru-Os sulfides from placers in Borneo [24]. Our S-isotope study of two morphological types (i.e., individual Ru-Os sulfide grains and laurite inclusions in Os-Ir-(Ru) alloys representing the primary PGM assemblage at Verkh-Neivinsk) is indicative of a sub-chondritic source of sulfur. This conclusion is consistent with the osmium isotope data obtained for Os-bearing PGM from the Verkh-Neivinsk massif (Middle Urals). The considerable range of the sub-chondritic 187Os/188Os values in Ru-Os sulfides (0.11728–0.12788, n = 19, Figure 11) and Ru-Os-Ir alloys (0.11619–0.12270, n = 34, Figure 11) are clearly indicative of derivation from a sub-chondritic source. This wide 187Os/188Os range, with rare exceptions [35,63], is similar to that of the PGM from podiform chromitites within the mantle sections of dunite-harzburgite massifs and associated placer deposits (Figure 11, see also Figure 11 in Reference [36]). On the other hand, the osmium isotope data display a restricted range of sub-chondritic 187Os/188Os values for intimately intergrown laurite type 2 and Os-rich alloy pairs that form the primary PGM assemblage (Figure 9a,b). In such pairs, the Os-isotope signature of the adjacent phases is indistinguishable. This is consistent with similar findings for PGM from Witwatersrand, South Africa [42], Shetland, Scotland [35], and Hochgrossen, Eastern Alps, Austria [49].
A single value of 187Os/188Os = 0.13459 ± 0.00002 identified in the erlichmanite indicates derivation from the source that evolved with long-term supra-chondritic Re/Os. This feature can be interpreted as evidence of a radiogenic crustal component, which was introduced during a subduction-related event or alternatively as an indication of an enriched mantle source. Consequently, supra-chondritic 187Os/188Os values (>0.12810), which have also been identified in detrital Os-Ir-(Ru) alloy grains [30,58,94,95], may indicate derivation from a distinct source, which is different from that of residual dunite-harzburgite sequences of an ophiolite complex. Distinct sources of HSE have recently been confirmed for Os-rich alloys derived from different lithologies (i.e., chromitite and clinopyroxenite) of the Kondyor massif [66] that was advocated to have trans-lithospheric mantle origin [96,97].
The time of formation of the oceanic crust in the Uralian ophiolites is usually ascribed to Early Devonian to Middle Ordovician (about 390 to 470 Ma) by Sm-Nd mineral and whole-rock isochrons on ultramafic rocks and gabbros from the Kempirsai massif [98,99] and by U-Pb dating of zircon from rock lithologies of the Vostochny Tagil (Middle Urals) and Nurali (South Urals) ultramafic complexes [100,101]. With the exception of two outliers (samples 160 and 161), the obtained TRD ages of Ru-Os sulfides at Verkh-Neivinsk imply that the mantle domain under Middle Urals experienced melt extraction between 1525 and 435 Ma (Table 4, Figure 12). The Os isotopic compositions of these PGM indicate that they record much older melting events than it would be expected from a single-melting model of un-depleted mantle around 440 Ma. One of the explanations of this phenomenon is that after their formation, Ru-Os sulfides remained isolated from the convecting upper mantle. In this case, ultramafic rocks of the Verkh-Neivinsk massif do not represent a simple residue after partial melting at a mid-ocean ridge setting or evolved back-arc system in the Early Paleozoic. Instead, they may represent a mixture of (1) refractory isolated lithospheric blocks that retain much older ages and (2) ultramafic rocks formed during a partial melting episode in the Early Paleozoic. A similar scenario has been advocated by Parkinson et al. [102] and Snow and Schmidt [103] for the Izu-Bonina-Mariana and Zabargad peridotites, respectively. Osmium isotope systematics suggest that melt depletion events recorded by un-radiogenic 187Os/188Os at Verkh-Neivinsk (Figure 11) and some other peridotite occurrences worldwide, e.g., References [59,62,102,103], etc., are significantly older than the time of their emplacement into crustal levels. This observation is similar to the phenomenon recorded by Re-Os isotopes in sulfide inclusions in diamonds [104]. Variations in the TRD ages of PGM at Verkh-Neivinsk point to prolonged melt-extraction processes and likely multi-stage evolution of HSE within the upper mantle. This is consistent with statistically significant data for Ru-Os-Ir alloys from the dunite-harzburgite massifs of the Urals [39] that show several stages of PGM formation with an average cycle of 150–200 Ma. This variability is likely to be due to discrete mantle melting events, which are probably controlled by deep mantle geodynamic processes [105]. The observed coincidence between the TRD ages of PGM and U-Pb ages of zircon recovered from the ultramafic massifs of the Urals [39,59,98,106,107,108,109] provides a feasible evidence of close relationships between magmatic and ore-forming processes.

6. Conclusions

  • A multi-technique approach, including the use of in-situ analytical methods for geochemical and isotopic analysis, provided a new set of mineralogical and S-Os isotope-geochemical constraints on the origin of detrital Ru-Os sulfides from primary PGM assemblage of the Verkh-Neivinsk ophiolite-type massif.
  • Ru-Os sulfides are recognized within two morphological types, including (i) solitary Ru-Os sulfide grains that have sizes from 0.5 to 1.5 mm and a wide compositional range for the laurite (RuS2)–erlichmanite (OsS2) solid solution series, and (ii) tiny euhedral inclusions of laurite hosted by Os-Ir(Ru) alloys. The primary nature of Ru-Os sulfides is supported by the occurrence of euhedral inclusions of high-Mg olivine (Fo92–94) that fall within the compositional range of mantle (primitive) olivine (Fo 88–93).
  • The δ34S values in solitary Ru-Os sulfide grains of type 1 have a narrow range from 0.3 to 2.8‰, with a mean of 1.82 ± 0.83‰ (n = 14), corresponding, within an error, to that for laurite inclusions of type 2 characterized by δ34S variations ranging from 1.5 to 3.3‰ and a slightly higher δ34S mean of 2.66 ± 0.73‰ (n = 5). The similar sub-chondritic δ34S values reported for the detrital Ru-Os sulfides of the oceanic mantle origin [24,51] is consistent with derivation of sulfur from a sub-chondritic source.
  • The osmium isotope results identified two distinct sources of HSE for Ru-Os sulfides. A considerable range of the sub-chondritic 187Os/188Os values in Ru-Os sulfides (0.1173–0.1278, n = 18 [50], this study) and Ru-Os-Ir alloys (0.1162–0.1227, n = 34 [49], this study) clearly indicate a common near-chondritic source for the HSE.
  • The osmium isotope data display a restricted range of sub-chondritic 187Os/188Os values for intimately intergrown laurite type 2 and Os-rich alloy pairs that form the primary PGM assemblage. This is consistent with similar findings for PGM from Witwatersrand, South Africa [42], Shetland, Scotland [35], and Hochgrossen, Austria [49].
  • A single value of 187Os/188Os = 0.13459 ± 0.00002 identified in the erlichmanite indicated derivation from the source that evolved with a long-term supra-chondritic Re/Os. This feature may be interpreted as evidence of a radiogenic crustal component, which was introduced during a subduction-related event or an indication of an enriched mantle source. Consequently, supra-chondritic 187Os/188Os values (>0.12810) may indicate derivation from a distinct source other than residual dunite–harzburgite sequences of an ophiolite complex.
  • With the exception of two outliers (samples 160 and 161), the obtained TRD ages of Ru-Os sulfides at Verkh-Neivinsk imply that the mantle domain under Middle Urals experienced melt extraction between 1525 and 435 Ma, and they record much older melting events than would be expected from a single-melting model of un-depleted mantle around 440 Ma. We suggest that variations in the TRD ages of the Verkh-Neivinsk PGM point to prolonged melt-extraction processes and likely multi-stage evolution of HSE within the upper mantle.

Author Contributions

This work included contributions from all the authors. K.N.M., I.Y.B., E.A.B., V.V.M. and T.A.V. took part in analytical work, discussing the data, writing and revising the manuscript. All authors have read and agreed to the published version of the manuscript.

Funding

This study was supported by Ministry of Science and Higher Education of the Russian Federation (state assignment # AAAA-A18-118052590026-5) and Russian Foundation for Basic Research (grant 18-05-00988-a to Inna Badanina).

Acknowledgments

The manuscript has benefitted from constructive comments of three anonymous reviewers and careful handling and editorial input by Editor Mauricio Calderón. The analytical work at CCFS/GEMOC was funded by DEST Systemic Infrastructure—Department of Education, Science and Training Systemic Infrastructure (Australia) Grants, ARC LIEF, NCRIS, industry partners, and Macquarie University. We thank Vera Khiller and Vladislav Bulatov for help in the microprobe lab. This is contribution 1614 from the ARC Centre of Excellence for Core to Crust Fluid Systems and 1436 in the GEMOC Key Centre. The Os-isotope data were obtained using instrumentation funded by DEST Systemic Infrastructure Grants, ARC LIEF, NCRIS/AuScope, industry partners and Macquarie University.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Augé, T. Platinum-group-mineral inclusions inophiolitic chromite from the Vourinos Complex, Greece. Can. Mineral. 1985, 23, 163–171. [Google Scholar]
  2. Augé, T. Platinum-group minerals in the Tiebaghi and Vourinos ophiolitic complexes: Genetic implications. Can. Mineral. 1988, 26, 177–192. [Google Scholar]
  3. Rudashevsky, N.S. Platinum-Group Elements in Rocks of Ultramafic Formations (Mineralogy and Genesis). Habil. Thesis, Mining Institute, Leningrad, Russia, 1989. (In Russian). [Google Scholar]
  4. Cabri, L.-J.; Harris, D.C.; Weiser, T.W. Mineralogy and distribution of platinum-group mineral (PGM) placer deposits of the world. Explor. Min. Geol. 1996, 5, 73–167. [Google Scholar]
  5. Garuti, G.; Zaccarini, F.; Moloshag, V.; Alimov, V. Platinum-group minerals as indicators of sulfur fugacity in ophiolitic upper mantle: An example from chromitites of the Rai-Iz ultramafic complex, Polar Urals, Russia. Can. Mineral. 1999, 37, 1099–1115. [Google Scholar]
  6. Melcher, F. Chromite and Platinum-Group Elements as Indicators of Mantle Petrogenesis. Mining University of Leoben, Leoben, Austria, 2000. Unpublished Habil Thesis. [Google Scholar]
  7. Zaccarini, F.; Pushkarev, E.; Garuti, G. Platinum-group element mineralogy and geochemistry of chromitite of the Kluchevskoy ophiolite complex, central Urals (Russia). Ore Geol. Rev. 2008, 33, 20–30. [Google Scholar] [CrossRef]
  8. Zaccarini, F.; Pushkarev, E.; Garuti, G.; Kazakov, I. Platinum-group minerals and other accessory phases in chromite deposits of the Alapaevsk ophiolite, Central Urals, Russia. Minerals 2016, 6, 108. [Google Scholar] [CrossRef] [Green Version]
  9. Malitch, K.N.; Thalhammer, O.A.R.; Knauf, V.V.; Melcher, F. Diversity of platinum-group mineral assemblages in banded and podiform chromitite from the Kraubath ultramafic massif, Austria: Evidence for an ophiolitic transition zone? Miner. Depos. 2003, 38, 282–297. [Google Scholar] [CrossRef]
  10. González-Jiménez, J.M.; Gervilla, F.; Proenza, J.A.; Augé, T.; Kerestedjian, T. Distribution of platinum-group minerals in ophiolitic chromitites. Appl. Earth Sci. 2010, 118, 101–110. [Google Scholar] [CrossRef]
  11. Badanina, I.Y.; Malitch, K.N.; Lord, R.A.; Meisel, T.C. Origin of primary PGM assemblage in chromitite from a mantle tectonite at Harold’s Grave (Shetland Ophiolite Complex, Scotland). Mineral. Petrol. 2013, 107, 963–970. [Google Scholar] [CrossRef]
  12. González-Jiménez, J.M.; Griffin, W.L.; Gervilla, F.; Proenza, J.A.; O’Reilly, S.Y.; Pearson, N.J. Chromitites in ophiolites: How, where, when, why? Part I. A review and new ideas on the origin and significance of platinum-group minerals. Lithos 2014, 189, 127–139. [Google Scholar] [CrossRef]
  13. Kiseleva, O.N.; Zhmodik, S.M.; Damdinov, B.B.; Agafonov, L.V.; Belyanin, D.K. Composition and evolution of PGE mineralization in chromite ores from the Il’chir ophiolite complex (Ospa-Kitoi and Khara-Nur areas, East Sayan). Russ. Geol. Geophys. 2014, 55, 259–272. [Google Scholar] [CrossRef]
  14. O’Driscoll, B.; González-Jiménez, J.M. Petrogenesis of the platinum-group minerals. Rev. Mineral. Geochem. 2016, 81, 489–578. [Google Scholar] [CrossRef] [Green Version]
  15. Kiseleva, O.; Zhmodik, S. PGE mineralization and melt composition of chromitites in Proterozoic ophiolite complexes of Eastern Sayan, Southern Siberia. Geosci. Front. 2017, 8, 721–731. [Google Scholar] [CrossRef] [Green Version]
  16. Massalski, T.B.; Murray, J.L.; Bennet, L.H.; Baker, H. Binary Alloy Phase Diagrams; American Society for Metals: Russel Township, OH, USA, 1993; 2224p. [Google Scholar]
  17. Amosse´, J.; Dable´, P.; Allibert, M. Thermochemical behaviour of Pt, Ir, Rh, and Ru vs fO2 and fS2 in a basaltic melt. Implications for the differentiation and precipitation of these elements. Miner. Pet. 2000, 68, 29–62. [Google Scholar]
  18. Andrews, D.R.A.; Brenan, J.M. Phase-equilibrium constraints on the magmatic origin of laurite + Ru-Os-Ir alloy. Can. Miner. 2002, 40, 1721–1735. [Google Scholar] [CrossRef]
  19. Brenan, J.M.; Andrews, D. High-temperature stability of laurite and Ru–Os–Ir alloy and their role in PGE fractionation in mafic magmas. Can. Mineral. 2001, 39, 341–360. [Google Scholar] [CrossRef]
  20. Fonseca, R.O.C.; Laurenz, V.; Mallmann, G.; Luguet, A.; Hoehne, N.; Jochum, K.P. New constraints on the genesis and long-term stability of Os-rich alloys in the Earth’s mantle. Geochim. Cosmochim. Acta 2012, 87, 227–242. [Google Scholar] [CrossRef]
  21. Fonseca, R.O.C.; Brückel, K.; Bragagni, A.; Leitzke, F.P.; Speelmanns, I.M.; Wainwright, A.N. Fractionation of rhenium from osmium during noble metal alloy formation in association with sulfides: Implications for the interpretation of model ages in alloy-bearing magmatic rocks. Geochim. Cosmochim. Acta 2017, 216, 184–200. [Google Scholar] [CrossRef]
  22. Badanina, I.Y.; Zharkova, E.V.; Kadik, A.A.; Malitch, K.N.; Murzin, V.V. Results of experimental determination of the intrinsic oxygen fugacity of Ru-Os-Ir alloys from the Verkh-Neivinsky dunite-harzburgite massif, Middle Urals, Russia. Geochem. Int. 2015, 53, 658–663. [Google Scholar] [CrossRef]
  23. González-Jiménez, J.M.; Gervilla, F.; Proenza, J.A.; Kerestedjian, T.; Augé, T.; Bailly, L. Zoning of laurite (RuS2)-erlichmanite (OsS2): Implications for the genesis of PGM in ophiolite chromitites. Eur. J. Mineral. 2009, 21, 419–432. [Google Scholar] [CrossRef] [Green Version]
  24. Hattori, K.H.; Cabri, L.J.; Johanson, B.; Zientek, M.L. Origin of placer laurite from Borneo: Se and As contents, and S isotopic compositions. Mineral. Mag. 2004, 68, 353–368. [Google Scholar] [CrossRef]
  25. Hattori, K.; Hart, S.R. Osmium-isotope ratios of platinum-group minerals associated with ultramafic intrusions: Os-isotopic evolution of the oceanic mantle. Earth Planet. Sci. Lett. 1991, 107, 499–514. [Google Scholar] [CrossRef]
  26. Hattori, K.; Cabri, L.J. Origin of platinum-group mineral nuggets inferred from an osmium-isotope study. Can. Mineral. 1992, 30, 289–301. [Google Scholar]
  27. Shi, R.; Alard, O.; Zhi, X.; O’Reilly, S.Y.; Pearson, N.J.; Griffin, W.L.; Zhang, M.; Chen, X. Multiple events in the Neo-Tethyan oceanic upper mantle: Evidence from Ru–Os–Ir alloys in the Luobusa and Dongqiao ophiolitic podiform chromitites, Tibet. Earth Planet. Sci. Lett. 2007, 261, 33–48. [Google Scholar] [CrossRef]
  28. Malitch, K.N.; Junk, S.A.; Thalhammer, O.A.R.; Melcher, F.; Knauf, V.V.; Pernicka, E.; Stumpfl, E.F. Laurite and ruarsite from podiform chromitites at Kraubath and Hochgrцssen, Austria: New insights from osmium isotopes. Can. Mineral. 2003, 41, 331–352. [Google Scholar] [CrossRef] [Green Version]
  29. Ahmed, A.H.; Hanghøj, K.; Kelemen, P.B.; Hart, S.R.; Arai, S. Osmium isotope systematics of the Proterozoic and Phanerozoic ophiolitic chromitites: In-situ ion probe analysis of primary Os-rich PGM. Earth Planet. Sci. Lett. 2006, 245, 777–791. [Google Scholar] [CrossRef]
  30. Pearson, D.G.; Parman, S.W.; Nowell, G.M. A link between large mantle melting events and continent growth seen in osmium isotopes. Nature 2007, 449, 202–205. [Google Scholar] [CrossRef] [PubMed]
  31. Nowell, G.M.; Pearson, D.G.; Parman, S.W.; Luguet, A.; Hanski, E. Precise and accurate 186Os/188Os and 187Os/188Os measurements by Multi-collector Plasma Ionisation Mass Spectrometry, part II: Laser ablation and its application to single-grain Pt–Os and Re–Os geochronology. Chem. Geol. 2008, 248, 394–426. [Google Scholar] [CrossRef]
  32. Marchesi, C.; González-Jiménez, J.M.; Gervilla, F.; Griffin, W.L.; O’Reilly, S.Y.; Proenza, J.A.; Pearson, N.J. In situ Re–Os isotopic analysis of platinum-group minerals from the Mayarí-Cristal ophiolitic massif (Mayarí-Baracoa Ophiolitic Belt, eastern Cuba): Implications for the origin of Os-isotope heterogeneities in podiform chromitites. Contrib. Mineral. Petrol. 2011, 161, 977–990. [Google Scholar] [CrossRef]
  33. González-Jiménez, J.M.; Griffin, W.L.; Gervilla, F.; Kerestedjian, T.N.; O’Reilly, S.Y.; Proenza, J.A.; Pearson, N.J.; Sergeeva, I. Metamorphism disturbs the Re-Os signatures of platinum-group minerals in ophiolite chromitites. Geology 2012, 40, 659–662. [Google Scholar] [CrossRef]
  34. González-Jimenéz, J.M.; Locmelis, M.; Belousova, E.; Griffin, W.; Gervilla, F.; Kerestedjian, T.N.; O’Reilly, S.Y.; Pearson, N.J.; Sergeeva, I. Genesis and tectonic implications of podiform chromitites in the metamorphosed ultramafic massif of Dobromirtsi (Bulgaria). Gondwana Res. 2015, 27, 555–574. [Google Scholar] [CrossRef]
  35. Badanina, I.Y.; Malitch, K.N.; Lord, R.A.; Belousova, E.A.; Meisel, T.C. Closed-system behaviour of the Re-Os isotope system recorded in primary and secondary PGM assemblages: Evidence from a mantle chromitite at Harold’s Grave (Shetland ophiolite Complex, Scotland). Ore Geol. Rev. 2016, 75, 174–185. [Google Scholar] [CrossRef] [Green Version]
  36. González-Jimenéz, J.M.; Mondal, S.K.; Ghosh, B.; Griffin, W.L.; O’Reilly, S.Y. Re-Os isotope systematics of sulfides in chromitites and host lherzolites of the Andaman ophiolite, India. Minerals 2020, 10, 686. [Google Scholar] [CrossRef]
  37. Kostoyanov, A.I. Model Re-Os ages of platinum-group minerals. Geol. Rudn. Mestorozhdenii 1998, 40, 545–550. (In Russian) [Google Scholar]
  38. Malitch, K.N.; Auge, T.; Badanina, I.Y.; Goncharov, M.M.; Junk, S.A.; Pernicka, E. Os-rich nuggets from Au-PGE placers of the Maimecha-Kotui Province, Russia: A multi-disciplinary study. Mineral. Petrol. 2002, 76, 121–148. [Google Scholar] [CrossRef]
  39. Kostoyanov, A.I.; Ivanov, D.Y.; Manoilov, V.V. Polycyclic formation of platinum-group minerals from placers of the Ural and Timan. Geochem. Int. 2003, 41, 534–544. [Google Scholar]
  40. Malitch, K.N.; Merkle, R.K.W. Ru-Os-Ir-Pt and Pt-Fe alloys from the Evander Goldfield (Witwatersrand Basin, South Africa): Detrital origin inferred from compositional and osmium isotope data. Can. Mineral. 2004, 42, 631–650. [Google Scholar] [CrossRef]
  41. Pašava, J.; Malec, J.; Griffin, W.L.; González-Jiménez, J.M. Re-Os isotopic constraints on the source of platinum-group minerals (PGMs) from the Vestřev pyrope-rich garnet placer deposit, Bohemian Massif. Ore Geol. Rev. 2015, 68, 117–126. [Google Scholar] [CrossRef]
  42. Badanina, I.Y.; Malitch, K.N.; Merkle, R.K.W.; Antonov, A.V.; Kapitonov, I.N.; Khiller, V.V. Chemical and isotopic composition of Os-rich alloys and sulfide from the Evander Goldfield of the Witwatersrand Basin (South Africa). Lithosphere 2016, 16, 129–144. (In Russian) [Google Scholar]
  43. Dijkstra, A.H.; Dale, C.W.; Oberthür, T.; Nowell, G.M.; Pearson, D.G. Osmium isotope compositions of detrital Os-rich alloys from the Rhine River provide evidence for a global late Mesoproterozoic mantle depletion event. Earth Planet. Sci. Lett. 2016, 452, 115–122. [Google Scholar] [CrossRef] [Green Version]
  44. González-Jiménez, J.M.; Griffin, W.L.; Proenza, J.A.; Gervilla, F.; O’Reilly, S.Y.; Akbulut, M.; Pearson, N.J.; Arai, S. Chromitites in ophiolites: How, where, when, why? Part II. The crystallisation of chromitites. Lithos 2014, 189, 140–158. [Google Scholar] [CrossRef]
  45. Murzin, V.V.; Sustavov, S.G.; Mamin, N.A. Gold and Platinum-Group Element Mineralization of Placer Deposits of the Verkh-Neivinskii Massif of Alpine Type Ultrabasites (Middle Urals); Ural State Mining University: Yekaterinburg, Russia, 1999; p. 93. (In Russian) [Google Scholar]
  46. Volchenko, Y.A.; Koroteev, V.A.; Neustroeva, I.I. Platinum-group elements in Alpine-type ultramafic rocks and related chromite ores of the Main Ophiolite Belt of the Urals. Geol. Ore Depos. 2009, 51, 162–178. [Google Scholar] [CrossRef]
  47. Badanina, I.Y.; Malitch, K.N.; Murzin, V.V.; Khiller, V.V.; Glavatskikh, S.P. Mineralogical and geochemical particularities of PGE mineralization of the Verkh-Neivinsk dunite-harzburgite massif (Middle Urals, Russia). Proc. Inst. Geol. Geochem. UB RAS 2013, 160, 188–192. (In Russian) [Google Scholar]
  48. Murzin, V.V.; Sustavov, S.G. New data about minerals of laurite-erlichmanite series and their As-bearing varieties. Dokl. Akad. Nauk 2000, 370, 380–382. (In Russian) [Google Scholar]
  49. Badanina, I.Y.; Malitch, K.N.; Belousova, E.A.; Murzin, V.V.; Lord, R.A. Osmium isotope systematics of Ru–Os–Ir alloys and Ru–Os sulfides of the dunite–harzburgite massifs: A synthesis of new data. Proc. Inst. Geol. Geochem. UB RAS 2014, 161, 167–172. (In Russian) [Google Scholar]
  50. Malitch, K.N.; Badanina, I.Y.; Belousova, E.A.; Murzin, V.V. Chemical and Os-isotopic composition of Ru-Os sulfides from Verkh-Neivinsky dunite-harzburgite massif (Middle Urals, Russia). Dokl. Earth Sci. 2018, 483, 1437–1441. [Google Scholar] [CrossRef]
  51. Murzin, V.V.; Badanina, I.Y.; Malitch, K.N.; Ignatiev, A.V.; Velivetskaya, T.A. Sulfur isotope composition of Ru-Os sulfides from the Verkh-Neivinsky dunite-harzburgite massif (Middle Urals, Russia): New data. Dokl. Earth Sci. 2019, 488, 1097–1099. [Google Scholar] [CrossRef]
  52. Riesberg, L.; Lorand, J.P. Longevity of subcontinental mantle lithosphere from osmium isotope systematics in orogenic peridotite massifs. Nature 1995, 376, 159–162. [Google Scholar] [CrossRef]
  53. Malitch, K.N. Platinum-Group Elements in Clinopyroxenite-Dunite Massifs of the Eastern Siberia (Geochemistry, Mineralogy, and Genesis); St. Petersburg Cartographic Factory VSEGEI Press: St. Petersburg, Russia, 1999; p. 296. (In Russian) [Google Scholar]
  54. Malitch, K.N.; Kostoyanov, A.I. Model Re-Os isotopic age of the PGE mineralization at the Gulinsk Massif (at the northern Siberian Platform, Russia). Geol. Ore Depos. 1999, 41, 126–135. [Google Scholar]
  55. Walker, R.J.; Prichard, H.M.; Ishiwatari, A.; Pimentel, M. The osmium isotopic composition of convecting upper mantle deduced from ophiolite chromites. Geochim. Cosmochim. Acta 2002, 66, 329–345. [Google Scholar] [CrossRef]
  56. Malitch, K.N. Osmium isotope constraints on contrasting sources and prolonged melting in the Proterozoic upper mantle: Evidence from ophiolitic Ru-Os sulfides and Ru-Os-Ir alloys. Chem. Geol. 2004, 208, 157–173. [Google Scholar] [CrossRef]
  57. Carlson, R.W. Application of the Pt–Re–Os isotopic systems to mantle geochemistry and geochronology. Lithos 2005, 82, 249–272. [Google Scholar] [CrossRef]
  58. Walker, R.J.; Brandon, A.D.; Bird, J.M.; Piccoli, P.M.; McDonough, W.F.; Ash, R.D. 187Os–186Os systematics of Os-Ir-Ry alloy grains from southwestern Oregon. Earth Planet. Sci. Lett. 2005, 230, 211–236. [Google Scholar] [CrossRef]
  59. Tessalina, S.G.; Bourdon, B.; Gannoun, A.; Campas, F.; Birck, J.-L.; Allegre, C.J. Complex proterozoic to paleozoic history of the upper mantle recorded in the Urals lherzolite massifs by Re–Os and Sm–Nd systematics. Chem. Geol. 2007, 240, 61–84. [Google Scholar] [CrossRef]
  60. Coggon, J.A.; Nowell, G.M.; Pearson, D.G.; Parman, S.W. Application of the 190Pt–186Os isotope system to dating platinum mineralization and ophiolite formation: An example from the Meratus Mountains, Borneo. Econ. Geol. 2011, 106, 93–117. [Google Scholar] [CrossRef]
  61. González-Jiménez, J.M.; Gervilla, F.; Griffin, W.L.; Proenza, J.A.; Augé, T.; O’Reilly, S.Y.; Pearson, N.J. Os-isotope variability within sulfides from podiform chromitites. Chem. Geol. 2012, 291, 224–235. [Google Scholar] [CrossRef]
  62. Tessalina, S.G.; Malitch, K.N.; Augé, T.; Puchkov, V.N.; Belousova, E.; McInnes, B. Origin of the Nizhny Tagil clinopyroxenite-dunite massif (Uralian Platinum Belt, Russia): Insights from PGE and Os isotope systematics. J. Petrol. 2005, 56, 2297–2318. [Google Scholar] [CrossRef] [Green Version]
  63. Malitch, K.N.; Anikina, E.V.; Badanina, I.Y.; Belousova, E.A.; Pushkarev, E.V.; Khiller, V.V. Chemical composition and osmium isotope systematics of primary and secondary platinum-group mineral assemblages from high-Mg chromitite of the Nurali lherzolite massif, South Urals, Russia. Geol. Ore Depos. 2016, 58, 1–19. [Google Scholar] [CrossRef]
  64. Malitch, K.N.; Belousova, E.A.; Griffin, W.L.; Badanina, I.Y.; Knauf, V.V.; O’Reilly, S.Y.; Pearson, N.J. Laurite and zircon from the Finero chromitites (Italy): New insights into evolution of the subcontinental mantle. Ore Geol. Rev. 2017, 90, 210–225. [Google Scholar] [CrossRef]
  65. Luguet, A.; Nowell, G.M.; Pushkarev, E.; Ballhaus, C.; Wirth, R.; Schreiber, A.; Gottman, I. 190Pt-186Os geochronometer reveals open system behaviour of 190Pt-4He isotope system. Geochem. Perspect. Lett. 2019, 11, 44–48. [Google Scholar] [CrossRef] [Green Version]
  66. Malitch, K.N.; Puchtel, I.S.; Belousova, E.A.; Badanina, I.Y. Contrasting platinum-group mineral assemblages of the Kondyor massif (Russia): Implications for the sources of HSE in zoned-type ultramafic massifs. Lithos 2020, 376–377, 105800. [Google Scholar] [CrossRef]
  67. Pearson, N.J.; Alard, O.; Griffin, W.L.; Jackson, S.E.; O’Reilly, S.Y. In situ measurement of Re-Os isotopes in mantle sulfides by laser ablation multicollector-inductively coupled plasma mass spectrometry: Analytical methods and preliminary results. Geochim. Cosmochim. Acta 2002, 66, 1037–1050. [Google Scholar] [CrossRef]
  68. Lorand, J.-P.; Alard, O. Platinum-group element abundances in the upper mantle: New constraints from in situ and whole-rock analyses of Massif Central xenoliths (France). Geochim. Cosmochim. Acta 2001, 65, 2789–2806. [Google Scholar] [CrossRef]
  69. Malitch, K.N.; Lopatin, G.G. New data on the metallogeny of the unique Guli clinopyroxenite-dunite Massif, Northern Siberia, Russia. Geol. Ore Depos. 1997, 39, 209–218. [Google Scholar]
  70. Merkle, R.K.W.; Malitch, K.N.; Grasser, P.P.H.; Badanina, I.Y. Native osmium from the Guli Massif, Northern Siberia (Russia). Mineral. Petrol. 2012, 104, 115–127. [Google Scholar] [CrossRef]
  71. Shirey, S.B.; Walker, R.J. The Re-Os isotope system in cosmochemistry and high-temperature geochemistry. Annu. Rev. Earth Planet. Sci. 1998, 26, 423–500. [Google Scholar] [CrossRef]
  72. Walker, R.J.; Carlson, R.W.; Shirey, S.B.; Boyd, F.R. Os, Sr, Nd, and Pb isotope systematics of Southern African peridotite xenoliths: Implications for the chemical evolution of subcontinental mantle. Geochim. Cosmochim. Acta 1989, 53, 1583–1595. [Google Scholar] [CrossRef]
  73. Smoliar, M.I.; Walker, R.J.; Morgan, J.W. Re-Os ages of group IIA, IIIA, IVA, and IVB meteorites. Science 1996, 271, 1099–1102. [Google Scholar] [CrossRef]
  74. Walker, R.J.; Horan, M.F.; Morgan, J.W.; Becker, H.; Grossman, J.N.; Rubin, A.E. Comparative 187Re-187Os systematics of chondrites: Implications regarding early solar system processes. Geochim. Cosmochim. Acta 2002, 66, 4187–4201. [Google Scholar] [CrossRef]
  75. Yin, Q.; Jagoutz, E.; Palme, H.; Wanke, H. NUR—A possible proxy for CHUR reference for Re-Os system derived from 187Os/188Os ratio of the Allende CAI. In Proceedings of the Lunar and Planetary Science Conference XXVII, Houston, TX, USA, 18–22 March 1996; pp. 1475–1476. [Google Scholar]
  76. Meisel, T.; Walker, R.J.; Irving, A.J.; Lorand, J.-P. Osmium isotopic composition of mantle xenoliths: A global perspective. Geochim. Cosmochim. Acta 2001, 65, 1311–1323. [Google Scholar] [CrossRef]
  77. Ignatiev, A.V.; Velivetskaya, T.A.; Budnitskiy, S.Y.; Yakovenko, V.V.; Vysotskiy, S.V.; Levitskii, V.I. Precision analysis of multisulfur isotopes in sulfides by femtosecond laser ablation GC-IRMS at high spatial resolution. Chem. Geol. 2018, 493, 316–326. [Google Scholar] [CrossRef]
  78. Velivetskaya, T.A.; Ignatiev, A.V.; Yakovenko, V.V.; Vysotskiy, S.V. An improved femtosecond laser-ablation fluorination method for measurements of sulfur isotopic anomalies (∆33S and ∆36S) in sulfides with high precision. Rapid Commun. Mass Spectrom. 2019, 33, 1722–1729. [Google Scholar] [CrossRef] [PubMed]
  79. Harris, D.C.; Cabri, L.J. Nomenclature of platinum-group-element alloys: Review and revision. Can. Mineral. 1991, 29, 231–237. [Google Scholar]
  80. Boyd, F.R.; Mertzman, S.A. Composition and structure of the Kaapvaal lithosphere, southern Africa. In Magmatic Processes: Physicochemical Principles; Mysen, B.O., Ed.; Geochemical Society: Washington, WA, USA, 1987; Volume 1, pp. 13–24. [Google Scholar]
  81. Gaul, O.F.; Griffin, W.L.; O’Reilly, S.Y.; Pearson, D.G. Mapping olivine compositions in the lithospheric mantle. Earth Planet. Sci. Lett. 2000, 182, 223–235. [Google Scholar] [CrossRef]
  82. Pearson, D.G.; Canil, D.; Shirey, S.B. Mantle samples included in volcanic rocks: Xenoliths and diamonds. In Treatise on Geochemistry, 2nd ed.; Holland, H.D., Turekian, K.K., Eds.; Elsevier: Amsterdam, The Netherlands, 2014; Volume 3, pp. 169–253. [Google Scholar]
  83. Badanina, I.Y.; Malitch, K.N.; Murzin, V.V.; Proskurnin, V.F. Geochemical particularities of PGE and gold in chromitites of dunite-harzburgite and clinopyroxenite-dunite massifs. Proc. Inst. Geol. Geochem. Ub Ras 2019, 166, 95–101. (In Russian) [Google Scholar]
  84. Melcher, F.; Grum, W.; Simon, G.; Thalhammer, T.V.; Stumpfl, E.F. Petrogenesis of the ophiolitic giant chromite deposits of Kempirsai, Kazakhstan: A study of solid and fluid inclusions in chromite. J. Petrol. 1997, 38, 1419–1458. [Google Scholar] [CrossRef]
  85. Bird, J.M.; Bassett, W.A. Evidence of a deep mantle history in terrestrial osmium-iridium-ruthenium alloys. J. Geophys. Res. 1980, 85, 5461–5470. [Google Scholar] [CrossRef]
  86. Cabri, L.J.; Harris, D.C. Zoning in Os–Ir alloys and the relation of the geological and tectonic environment of the source rocks to the bulk Pt:Pt+Ir+Os ratio for placers. Can. Mineral. 1975, 13, 266–274. [Google Scholar]
  87. Peck, D.C.; Keays, R.R.; Ford, R.J. Direct crystallization of refractory platinum-group element alloys from boninitic magmas: Evidence from western Tasmania. Aust. J. Earth Sci. 1992, 39, 373–387. [Google Scholar] [CrossRef]
  88. Bird, J.M.; Meibom, A.; Frei, R.; Nagler, T.F. Osmium and lead isotopes of rare OsIrRu minerals: Derivation from the core-mantle boundary region? Earth Planet. Sci. Lett. 1999, 170, 83–92. [Google Scholar] [CrossRef]
  89. Thode, H.G.; Monster, J.; Dunford, H.B. Sulphur isotope geochemistry. Geochim. Cosmochim. Acta 1961, 25, 159–174. [Google Scholar] [CrossRef]
  90. Gao, X.; Thiemens, M.H. Isotopic composition and concentration of sulfur in carbonaceous chondrites. Geochim. Cosmochim. Acta 1993, 57, 3159–3169. [Google Scholar] [CrossRef]
  91. Gao, X.; Thiemens, M.H. Variations in the isotopic composition of sulfur in enstatite and ordinary chondrites. Geochim. Cosmochim. Acta 1993, 57, 3171–3176. [Google Scholar] [CrossRef]
  92. Pushkarev, Y.D. Two types of interaction of crustal and mantle matter and a new approach to the problems of deep ore formation. Dokl. Russ. Acad. Sci. 1997, 335, 524–526. (In Russian) [Google Scholar]
  93. Ripley, E.M.; Li, C. Applications of stable and radiogenic isotopes to magmatic Cu-Ni-PGE deposits: Examples and cautions. Earth Sci. Front. 2007, 14, 124–132. [Google Scholar] [CrossRef]
  94. Meibom, A.; Frei, R.; Sleep, N.H. Osmium isotopic compositions of Os-rich platinum group element alloys from the Klamath and Siskiyou Mountains. J. Geophys. Res. 2004, 109, B02203. [Google Scholar] [CrossRef]
  95. Brandon, A.D.; Walker, R.J.; Puchtel, I.S. Platinum-osmium isotope evolution of the Earth’s mantle: Constraints from chondrites and Os-rich alloys. Geochim. Cosmochim. Acta 2006, 70, 2093–2103. [Google Scholar] [CrossRef]
  96. Lazarenkov, V.G.; Landa, E.A. Evidences for non-intrusive nature of the Kondyor massif and problems of the mantle diapirism. Proc. Russ. Acad. Sci. Geol. Ser. 1992, 6, 102–113. (In Russian) [Google Scholar]
  97. Burg, J.P.; Bodinier, J.-L.; Gerya, N.; Bedini, R.-M.; Boudier, F.; Dautria, J.-M.; Prikhodko, V.; Efimov, A.; Pupier, E.; Balanec, J.-L. Translithospheric mantle diapirism: Geological evidence and numerical modeling of the Kondyor zoned ultramafic complex (Russian Far-East). J. Petrol. 2009, 50, 289–321. [Google Scholar] [CrossRef]
  98. Edwards, R.; Wasserburg, G.J. The age and emplacement of obducted oceanic crust in the Urals from Sm–Nd and Rb–Sr systematics. Earth Planet. Sci. Lett. 1985, 72, 389–404. [Google Scholar] [CrossRef]
  99. Melcher, F.; Grum, W.; Thalhammer, T.V.; Thalhammer, O.A.R. The giant chromite deposits at Kempirsai, Urals: Constraints from trace element (PGE, REE) and isotope data. Miner. Depos. 1999, 34, 250–272. [Google Scholar] [CrossRef]
  100. Krasnobaev, A.A.; Valizer, P.M. Zircons and zircon geochronology of gabbro from the Nurali massif (Southern Urals). Lithosphere 2018, 18, 574–584. (In Russian) [Google Scholar] [CrossRef]
  101. Krasnobaev, A.A.; Rusin, A.I.; Busharina, S.V.; Rodionov, N.V. Zirconology of ultramafic rocks from the Vostochnotagilskii massif (Middle Urals). Dokl. Earth Sci. 2014, 455, 441–445. [Google Scholar] [CrossRef]
  102. Parkinson, I.J.; Hawkesworth, C.J.; Cohen, A.S. Ancient mantle in a modern arc: Osmium isotopes in Izu-Bonin-Mariana forearc peridotites. Science 1998, 281, 2011–2013. [Google Scholar] [CrossRef]
  103. Snow, J.E.; Schmidt, G. Proterozoic melting in the northern peridotite massif, Zabargad island: Os isotopic evidence. Terra Nova 1999, 11, 45–50. [Google Scholar] [CrossRef]
  104. Spetsius, Z.V.; Belousova, E.A.; Griffin, W.L.; O’Reilly, S.Y.; Pearson, N.J. Archean sulfide inclusions in Paleozoic zircon megacrysts from the Mir kimberlite, Yakutia: Implications for the dating of diamonds. Earth Planet. Sci. Lett. 2002, 199, 111–126. [Google Scholar] [CrossRef]
  105. Dobretsov, N.L.; Kirdyashkin, A.G. Deep-Level Geodynamics; Swets and Zeitlinger: Rotterdam, The Netherlands, 1998; 328p. [Google Scholar]
  106. Savelieva, G.N.; Suslov, P.V.; Larionov, A.N. Vendian tectono-magmatic events in mantle ophiolitic complexes of the Polar Urals: U-Pb dating of zircon from chromitite. Geotectonics 2007, 41, 105–113. [Google Scholar] [CrossRef]
  107. Fershtater, G.B. Paleozoic Intrusive Magmatism of the Middle and Southern Urals; Ural Branch of RAS: Ekaterinburg, Russia, 2013; 368p. (In Russian) [Google Scholar]
  108. Krasnobaev, A.A.; Anfilogov, V.N. Zircons: Implications for dunite genesis. Dokl. Earth Sci. 2014, 456, 535–538. [Google Scholar] [CrossRef]
  109. Krasnobaev, A.A.; Valizer, P.M.; Anfilogov, V.N.; Sergeev, S.A.; Rusin, A.I.; Busharina, S.V.; Medvedeva, E.V. Zirconology of ultrabasic rocks of the Karabash massif (Southern Urals). Dokl. Earth Sci. 2016, 469, 674–679. [Google Scholar] [CrossRef]
Minerals 11 00329 g001 550
Figure 1. (a) Scheme of location of ophiolite- and zoned-type massifs of the Urals. (1) dunite-harzburgite ophiolite-type massifs, (2) dunite-clinopyroxenite-gabbro zoned-type massifs of the Platinum belt. Box corresponds to inset in Figure 1b. (b) Tectonic scheme of the Middle Urals and position of the Verkh-Neivinsk massif. (1–6) intrusive formations: (1) granitic (granite, granodiorite, alaskite); (2) granitoid (granodiorite, tonalite, granite); (3) plagiogranitic (plagiogranite, quartz diorite); (4) gabbroic (gabbro, gabbronorite, diorite); (5) dunite-harzburgite (dunite, harzburgite, serpentinite, chromitite); (6) dunite–clinopyroxenite (dunite, chromitite, wehrlite, clinopyroxenite, horblendite); (7) rocks of the amphibolite, amphibolite–gneiss, gneiss, and migmatite associations; (8) volcanogenic sedimentary rocks of the island arc sector of the Urals; (9) flysch, flyschoid, molasse, and terrigenous–carbonate, and carbonate formations of the continental sector of the Urals; (10) boundaries of mega zones ((I) Western Urals, (II) Central Urals, (III) Tagil-Magnitogorsk, (IV) Eastern Urals, (V) Transurals); (11) sampling location.
Figure 1. (a) Scheme of location of ophiolite- and zoned-type massifs of the Urals. (1) dunite-harzburgite ophiolite-type massifs, (2) dunite-clinopyroxenite-gabbro zoned-type massifs of the Platinum belt. Box corresponds to inset in Figure 1b. (b) Tectonic scheme of the Middle Urals and position of the Verkh-Neivinsk massif. (1–6) intrusive formations: (1) granitic (granite, granodiorite, alaskite); (2) granitoid (granodiorite, tonalite, granite); (3) plagiogranitic (plagiogranite, quartz diorite); (4) gabbroic (gabbro, gabbronorite, diorite); (5) dunite-harzburgite (dunite, harzburgite, serpentinite, chromitite); (6) dunite–clinopyroxenite (dunite, chromitite, wehrlite, clinopyroxenite, horblendite); (7) rocks of the amphibolite, amphibolite–gneiss, gneiss, and migmatite associations; (8) volcanogenic sedimentary rocks of the island arc sector of the Urals; (9) flysch, flyschoid, molasse, and terrigenous–carbonate, and carbonate formations of the continental sector of the Urals; (10) boundaries of mega zones ((I) Western Urals, (II) Central Urals, (III) Tagil-Magnitogorsk, (IV) Eastern Urals, (V) Transurals); (11) sampling location.
Minerals 11 00329 g001
Minerals 11 00329 g002 550
Figure 2. Schematic geological map of the Verkh-Neivinsk massif with locations of Au-PGE placer deposits and studied PGM grains.
Figure 2. Schematic geological map of the Verkh-Neivinsk massif with locations of Au-PGE placer deposits and studied PGM grains.
Minerals 11 00329 g002
Minerals 11 00329 g003 550
Figure 3. Back-scattered images of laurite grains of type 1 at Verkh-Neivinsk: (a)—sample 153, (b)—sample 156, (c)—sample 159, (d)—sample 162, (e)—sample 166, (f)—detail of Figure 2c. LR—laurite, ERL—erlichmanite, (Os,Ir)—iridian osmium. Numbers 1–10 denote areas of electron microprobe analyses corresponding to the same numbers in Table 1 and Table 2.
Figure 3. Back-scattered images of laurite grains of type 1 at Verkh-Neivinsk: (a)—sample 153, (b)—sample 156, (c)—sample 159, (d)—sample 162, (e)—sample 166, (f)—detail of Figure 2c. LR—laurite, ERL—erlichmanite, (Os,Ir)—iridian osmium. Numbers 1–10 denote areas of electron microprobe analyses corresponding to the same numbers in Table 1 and Table 2.
Minerals 11 00329 g003
Minerals 11 00329 g004 550
Figure 4. Back-scattered electron images of forsterite inclusions in: (a) osmian iridium (Os,Ir), (b–d) laurite (LR). Numbers 1–9 denote areas of electron microprobe analyses corresponding to the same numbers in Table 3.
Figure 4. Back-scattered electron images of forsterite inclusions in: (a) osmian iridium (Os,Ir), (b–d) laurite (LR). Numbers 1–9 denote areas of electron microprobe analyses corresponding to the same numbers in Table 3.
Minerals 11 00329 g004
Minerals 11 00329 g005 550
Figure 5. X-ray maps of high-Mg olivine inclusion in laurite (sample 164). (a)—MgKα, (b)—FeKα, (c)—SiKα, (d)—RuLα, (e)—SKα.
Figure 5. X-ray maps of high-Mg olivine inclusion in laurite (sample 164). (a)—MgKα, (b)—FeKα, (c)—SiKα, (d)—RuLα, (e)—SKα.
Minerals 11 00329 g005
Minerals 11 00329 g006 550
Figure 6. Back-scattered images of laurite grains of type 2 at Verkh-Neivinsk: (a)—sample 9, (b)—sample 24, (c)—sample 26. LR—laurite, (Os,Ir)—iridian osmium. Numbers 11–16 denote areas of electron microprobe analyses corresponding to the same numbers in Table 2.
Figure 6. Back-scattered images of laurite grains of type 2 at Verkh-Neivinsk: (a)—sample 9, (b)—sample 24, (c)—sample 26. LR—laurite, (Os,Ir)—iridian osmium. Numbers 11–16 denote areas of electron microprobe analyses corresponding to the same numbers in Table 2.
Minerals 11 00329 g006
Minerals 11 00329 g007 550
Figure 7. Chemical composition of: (a) Ru-Os sulfides type 1, (b) coexisting laurite type 2 and Os-rich alloy grains, (c) Ru-Os-Ir alloys from the Verkh-Neivinsk massif in coordinates Ru-Os-Ir (at.%). Numbers 7–16 in Figure 7b correspond to the same numbers of electron microprobe analyses in Table 1 and Table 2. Squares and circles refer to laurite and Os alloy, respectively. Different symbol colors denote laurite–alloy pairs shown in Figure 3c,f and Figure 6. Numbers 1 and 2 in Figure 7c correspond to rutheniridosmine and miscibility gap, respectively (after nomenclature of Harris and Cabri [79]).
Figure 7. Chemical composition of: (a) Ru-Os sulfides type 1, (b) coexisting laurite type 2 and Os-rich alloy grains, (c) Ru-Os-Ir alloys from the Verkh-Neivinsk massif in coordinates Ru-Os-Ir (at.%). Numbers 7–16 in Figure 7b correspond to the same numbers of electron microprobe analyses in Table 1 and Table 2. Squares and circles refer to laurite and Os alloy, respectively. Different symbol colors denote laurite–alloy pairs shown in Figure 3c,f and Figure 6. Numbers 1 and 2 in Figure 7c correspond to rutheniridosmine and miscibility gap, respectively (after nomenclature of Harris and Cabri [79]).
Minerals 11 00329 g007
Minerals 11 00329 g008 550
Figure 8. Back-scattered electron images of Ru-Os sulfides type 1 at Verkh-Neivinsk: (a)—sample 153, (b)—sample 154, (c)—sample 155, (d)—sample 157, (e)—sample 159, (f)—sample 160, (g)—sample 162, (h)—sample 163, (i)—sample 161, (j)—sample 164, (k)—sample 166, (l)—sample 165. Yellow circles with a diameter of 15–40 μm denote areas of Os-isotope analyses listed in Table 4. Yellow numerals in the numerator and denominator correspond to the 187Os/188Os value and the measurement error, respectively. Black circles with a diameter ca. 100 μm denote spots of S-isotope analyses listed in Table 4. The numbers correspond to the δ34S (‰) value. LR—laurite, ERL—erlichmanite, (Os, Ir)—iridian osmium, OL—high-Mg olivine.
Figure 8. Back-scattered electron images of Ru-Os sulfides type 1 at Verkh-Neivinsk: (a)—sample 153, (b)—sample 154, (c)—sample 155, (d)—sample 157, (e)—sample 159, (f)—sample 160, (g)—sample 162, (h)—sample 163, (i)—sample 161, (j)—sample 164, (k)—sample 166, (l)—sample 165. Yellow circles with a diameter of 15–40 μm denote areas of Os-isotope analyses listed in Table 4. Yellow numerals in the numerator and denominator correspond to the 187Os/188Os value and the measurement error, respectively. Black circles with a diameter ca. 100 μm denote spots of S-isotope analyses listed in Table 4. The numbers correspond to the δ34S (‰) value. LR—laurite, ERL—erlichmanite, (Os, Ir)—iridian osmium, OL—high-Mg olivine.
Minerals 11 00329 g008
Minerals 11 00329 g009 550
Figure 9. Back-scattered electron images of Ru-Os sulfides type 2 and associated Os-rich alloys at Verkh-Neivinsk: (a)—sample 9, (b)—sample 24, (c)—sample 26. “Craters” with a diameter of 15–40 μm denote areas of Os-isotope analyses listed in Table 4. The numerals in the numerator and denominator correspond to the 187Os/188Os value and the measurement error, respectively. Black circles with a diameter ca. 100 μm denote spots of S-isotope analyses listed in Table 4. LR—laurite, (Os, Ir)—iridian osmium, (Os, Ru, Ir)—osmium.
Figure 9. Back-scattered electron images of Ru-Os sulfides type 2 and associated Os-rich alloys at Verkh-Neivinsk: (a)—sample 9, (b)—sample 24, (c)—sample 26. “Craters” with a diameter of 15–40 μm denote areas of Os-isotope analyses listed in Table 4. The numerals in the numerator and denominator correspond to the 187Os/188Os value and the measurement error, respectively. Black circles with a diameter ca. 100 μm denote spots of S-isotope analyses listed in Table 4. LR—laurite, (Os, Ir)—iridian osmium, (Os, Ru, Ir)—osmium.
Minerals 11 00329 g009
Minerals 11 00329 g010 550
Figure 10. Sulfur isotope data for Ru-Os sulfides of type 1 and 2 within primary PGM assemblage from the Verkh-Neivinsk massif.
Figure 10. Sulfur isotope data for Ru-Os sulfides of type 1 and 2 within primary PGM assemblage from the Verkh-Neivinsk massif.
Minerals 11 00329 g010
Minerals 11 00329 g011 550
Figure 11. Os-isotopic composition of Ru-Os sulfides and Ru-Os-Ir alloys of dunite-harzburgite massifs. Os-isotopic data for Ru-Os sulfides of the Kraubath and Hochgrossen massifs (Eastern Alps) and Ru-Os-Ir alloys from the Timan, Polar, and Middle Urals according to References [39,49,56]. Present-day enstatite chondrite reservoir after Reference [74].
Figure 11. Os-isotopic composition of Ru-Os sulfides and Ru-Os-Ir alloys of dunite-harzburgite massifs. Os-isotopic data for Ru-Os sulfides of the Kraubath and Hochgrossen massifs (Eastern Alps) and Ru-Os-Ir alloys from the Timan, Polar, and Middle Urals according to References [39,49,56]. Present-day enstatite chondrite reservoir after Reference [74].
Minerals 11 00329 g011
Minerals 11 00329 g012 550
Figure 12. Histogram of mantle-depletion (TRD) ages of Ru-Os sulfides at Verkh-Neivinsk.
Figure 12. Histogram of mantle-depletion (TRD) ages of Ru-Os sulfides at Verkh-Neivinsk.
Minerals 11 00329 g012
Table
Table 1. Electron microprobe analyses of Ru-Os sulfides of type 1 from the Verkh-Neivinsk massif.
Table 1. Electron microprobe analyses of Ru-Os sulfides of type 1 from the Verkh-Neivinsk massif.
Analysis123456789
Sample #153153153156156156159162166
MineralLRLRLRLRLRLRLRERLERL
FigureFigure 3aFigure 3aFigure 3aFigure 3bFigure 3bFigure 3bFigure 3cFigure 3dFigure 3e
wt. %
Feb.d.l.b.d.l.0.170.380.400.32b.d.l.b.d.l.b.d.l.
Nib.d.l.b.d.l.b.d.l.0.23b.d.l.b.d.l.b.d.l.b.d.l.b.d.l.
Ru37.2436.5237.1039.2038.0838.8931.6912.7421.48
Rh0.270.390.270.260.250.290.040.110.01
Os19.1619.0819.5820.7921.3421.5333.0451.2342.41
Ir10.3810.719.485.966.105.523.327.815.88
S33.2433.0833.8133.8733.8033.4232.1328.1729.63
Asb.d.l.b.d.l.b.d.l.b.d.l.b.d.l.b.d.l.b.d.l.b.d.l.b.d.l.
Total100.2999.78100.41100.6999.9799.97100.22100.0699.40
at.%
Fe0.000.000.190.430.450.360.000.000.00
Ni0.000.000.000.000.250.000.000.000.00
Ru23.5723.2723.2424.2723.7824.3920.809.5815.29
Rh0.170.250.160.160.150.180.030.080.01
Os6.456.466.526.847.087.1811.5320.4716.04
Ir3.463.593.121.942.001.821.153.092.21
S66.3566.4466.7766.1166.5466.0766.4966.7866.46
Ru #787878787777643249
LR—laurite, ERL—erlichmanite, Ru# = 100 × Ru at.%/(Ru + Os) at.%. b.d.l.—below the detection limit; the detection limits here and in Table 2 are as follows (wt.%): Os—0.15, Ir—0.75, Ru—0.24, Rh—0.01, Pt—0.09, Pd—0.27, Fe—0.15, Ni—18, Cu—0.15, S—0.13, As—0.01.
Table
Table 2. Electron microprobe analyses of Ru-Os sulfides of type 2 and coexisting Os-Ir alloys from the Verkh-Neivinsk massif.
Table 2. Electron microprobe analyses of Ru-Os sulfides of type 2 and coexisting Os-Ir alloys from the Verkh-Neivinsk massif.
Analysis10111213141516
Sample #1599924242626
Mineral(Os,Ir)laurite(Os,Ir)laurite(Os,Ir)laurite(Os,Ir)
FigureFigure 3eFigure 6aFigure 6aFigure 6bFigure 6bFigure 6cFigure 6c
wt.%
Feb.d.l.b.d.l.b.d.l.b.d.l.b.d.l.0.270.22
Ru1.2626.981.3449.5611.4422.810.95
Rhb.d.l.b.d.l.b.d.l.0.250.150.12b.d.l.
Os89.1336.9283.8211.4477.5136.9957.26
Ir9.384.5414.661.8310.498.2841.55
Sb.d.l.31.34b.d.l.36.95b.d.l.31.30b.d.l.
Total99.7799.7899.82100.0399.5999.7799.98
at.%
Fe0.000.000.000.000.000.330.74
Ru2.3518.262.5028.5919.6215.611.77
Rh0.000.000.000.140.260.080.00
Os88.4413.2883.123.5170.6613.4556.75
Ir9.211.6214.380.569.462.9840.74
S0.0066.840.0067.200.0067.550.00
Ru # 56 89 54
(Os,Ir)—iridian osmium. Ru# = 100 × Ru at.%/(Ru + Os) at.%. b.d.l.—below the detection limit; detection limit for concentrations in iridian osmium were as follows, wt.%: Os—0.18, Ir—0.85, Ru—0.27, Rh—0.11, Pt—0.99, Pd—0.30, Fe—0.16, Ni—0.18, Cu—0.15, S—0.06, As—0.03.
Table
Table 3. Electron microprobe analyses of high-Mg olivine inclusions in osmian iridium and Ru-Os sulfides from primary PGM assemblage of the Verkh-Neivinsk massif.
Table 3. Electron microprobe analyses of high-Mg olivine inclusions in osmian iridium and Ru-Os sulfides from primary PGM assemblage of the Verkh-Neivinsk massif.
Analysis123456789
Sample #8164164164154154154165165
FigureFigure 4aFigure 4bFigure 4bFigure 4bFigure 4cFigure 4cFigure 4cFigure 4dFigure 4d
Host mineral(Ir,Os)LRLRLRLRLRLRLRLR
wt.%
SiO240.3340.6840.5540.3939.7240.9640.7440.7341.21
MgO50.4250.6950.6150.6151.9251.8351.6652.2352.37
FeO6.707.727.737.786.106.646.336.195.95
NiO0.400.330.340.350.420.410.420.140.17
MnO0.130.060.140.110.080.090.100.250.32
Total97.9899.4899.3799.2498.2499.9399.2599.54100.02
ApfuCations on the basis of 4 O atoms
Si1.000.990.990.990.980.990.990.990.99
Mg1.861.851.851.851.911.871.881.891.88
Fe2+0.140.160.160.160.130.140.130.130.12
Ni0.010.010.010.010.010.010.010.000.00
Mn0.000.000.000.000.000.000.000.010.01
Fo93 92 92 92 94 93 94 94 94
(Ir,Os)—osmian iridium, LR—laurite, ERL—erlichmanite, (Ru,Os,Ir)—ruthenium; Al2O3, CaO, TiO2, and Cr2O3 were below the detection limit, Fo = 100 × Mg/(Mg + Fe).
Table
Table 4. Sulfur and osmium isotope data of Ru-Os sulfides and associated Os-rich alloys at Verkh-Neivinsk.
Table 4. Sulfur and osmium isotope data of Ru-Os sulfides and associated Os-rich alloys at Verkh-Neivinsk.
Sample Number, FigureMineral, Ru#187Os/188Os *1σ *187Re/188Os *TRDECR* (Ga)1σ
(Ga)		δ34S, ‰
Ru-Os sulfides of type 1 and inclusions of iridian osmium
153, Figure 8aLR, 780.121350.000030.000020.9550.0042.5
154, Figure 8bLR, 77 0.123810.000030.000090.6090.0042.0
156, Figure 3bLR, 770.123860.000020.000030.6020.0032.2
157, Figure 8dLR, 750.122010.000020.000050.8630.0022.2
159-1, Figure 3c and Figure 8eLR, 640.117280.000020.000011.5230.0032.6
159-2, Figure 3f and Figure 8e(Os,Ir)0.117200.000090.000231.5350.012-
163, Figure 8hLR, 750.125030.000010.000030.4360.0021.9
164-1, Figure 8jLR, 890.119460.000030.000041.2190.0040.5
164-2, Figure 8jLR, 89 0.119430.000040.000021.2230.0050.6
165, Figure 8lLR, 640.118890.000020.000061.2980.0020.3
155, Figure 8cERL, 320.122130.000020.000020.8450.0031.9
160, Figure 8fERL, 440.127880.000030.00060.0290.0051.7
161, Figure 8iERL, 12 0.134590.000020.00002--2.8
162, Figure 3d and Figure 8gERL, 320.122610.000020.000030.7780.0021.7
166, Figure 3e and Figure 8k ERL, 490.120610.000010.000021.0590.0022.7
Ru-Os sulfides of type 2 and associated Os-rich alloys
9, Figure 9aLR, 56 0.123020.000030.000020.7200.004n/d
9, Figure 9a (Os,Ir)0.123060.000020.000090.7140.003-
24, Figure 9bLR, 89 0.117740.000040.000011.4590.0063.1
24, Figure 9b(Os,Ru,Ir)0.117860.000020.000031.4430.003-
26, Figure 9c LR, 540.125060.000020.000020.4320.0033.3
26, Figure 9c(Os,Ir)0.125120.000010.000360.4230.002-
71LR, 890.124910.000030.000080.4530.0052.4
71(Os,Ir,Ru) 0.125050.000020.000330.4340.002-
126LR, 1000.124100.000130.000190.5680.0181.5
194LR, 100 0.118980.000090.000311.2860.014n/d
194(Ru,Os,Ir)0.118910.000030.001401.2960.004-
Ru# = 100 × Ru at.%/(Ru + Os) at.%. *—data after Reference [50], except sample numbers 160 and 126. TRDECR values estimated by Walker et al. [74] and a decay constant of λ = 1.666 × 10−11 year−1 [73]. Uncertainties on model ages are based on within-run errors only. LR—laurite; ERL—erlichmanite; (Os,Ir), (Os, Ru, Ir), (Os,Ir,Ru)—osmium; (Ru,Os,Ir)—ruthenium, n/d—not determined.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Malitch, K.N.; Badanina, I.Y.; Belousova, E.A.; Murzin, V.V.; Velivetskaya, T.A. Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence. Minerals 2021, 11, 329. https://doi.org/10.3390/min11030329

AMA Style

Malitch KN, Badanina IY, Belousova EA, Murzin VV, Velivetskaya TA. Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence. Minerals. 2021; 11(3):329. https://doi.org/10.3390/min11030329

Chicago/Turabian Style

Malitch, Kreshimir N., Inna Yu. Badanina, Elena A. Belousova, Valery V. Murzin, and Tatiana A. Velivetskaya. 2021. "Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence" Minerals 11, no. 3: 329. https://doi.org/10.3390/min11030329

APA Style

Malitch, K. N., Badanina, I. Y., Belousova, E. A., Murzin, V. V., & Velivetskaya, T. A. (2021). Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence. Minerals, 11(3), 329. https://doi.org/10.3390/min11030329

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