Platinum group minerals from the deluvial placer of the Veresovka River, Veresovoborsky dunite-clinopyroxenite massif (the Middle Urals)

The note describes the mineralogical and geochemical features of platinum-bearing vein-disseminated and massive chromitite from the dunites of the Svetloborsky, Veresovoborsky and Kamenushensky clinopyroxenite-dunite intrusions located in the Middle Urals. It was found that platinum in chromitites has an extremely uneven distribution and is concentrated in the form of Pt-Fe intermetallides. The texture-structural features of the chromitites studied, the distribution of platinum group elements and the composition of chromoshpinelides in them are similar to the detailed study of the chromitites of the zonal clinopyroxenite-dunite intrusions of the Urals (Nizhnetagilsky) and Koryakia (Gal’moenan).

Download Full-text

Platinum-group minerals from the Malaya Kamenushka River placer, Middle Urals, Russia

Mineralogical Magazine ◽

10.1180/mgm.2020.87 ◽

2020 ◽

pp. 1-13

Author(s):

Roman S. Palamarchuk ◽

Sergey Yu. Stepanov ◽

Aleksandr V. Kozlov ◽

Dmitry A. Khanin ◽

Dmitry A. Varlamov ◽

...

Keyword(s):

Platinum Group Element ◽

Group Element ◽

Middle Urals ◽

Group Mineral ◽

Refractory Elements ◽

Platinum Belt ◽

Platinum Group Minerals ◽

Platinum Group ◽

Primary Substrate ◽

Vertical Zoning

Abstract This work presents a detailed study of platinum-group mineral (PGM) assemblages from the Malaya Kamenushka River placer, whose formation is associated with the weathering of the Kamenushensky Uralian–Alaskan type massif, Middle Urals, Russian Federation. The deposit is characterised by the dominance of isoferroplatinum, together with significant numbers of inclusions of Os–Ir–Ru alloys and platinum-group element (PGE) sulfides. A study of the Os–Ir–Ru alloys permitted recognition of two types of iridium with different morphology and composition. The similarity of the PGM assemblages from the Malaya Kamenushka River placer and the lode mineralisation of the Kamenushensky massif is demonstrated. A comparison of PGM assemblages from the Malaya Kamenushka River placer with other placers and massifs of the Ural platinum belt demonstrates significant differences in the number of Os–Ir–Ru inclusions. Such differences for minerals of refractory elements cannot be explained by the vertical zoning of the lode mineralisation. Most probably this is associated with the enrichment of the primary substrate with Os, Ir and Ru and/or the degree of melting, depending on the chosen model of formation of the Uralian–Alaskan type massifs.

Download Full-text

Platinum-Group Minerals of Pt-Placer Deposits Associated with the Svetloborsky Ural-Alaskan Type Massif, Middle Urals, Russia

Minerals ◽

10.3390/min9020077 ◽

2019 ◽

Vol 9 (2) ◽

pp. 77 ◽

Cited By ~ 4

Author(s):

Sergey Stepanov ◽

Roman Palamarchuk ◽

Aleksandr Kozlov ◽

Dmitry Khanin ◽

Dmitry Varlamov ◽

...

Keyword(s):

Morphological Features ◽

Middle Urals ◽

Transport Distance ◽

Mechanical Attrition ◽

Platinum Group Minerals ◽

Placer Deposits ◽

Fe Alloys ◽

Platinum Group ◽

Ore Zones

The alteration of platinum group minerals (PGM) of eluval, proximal, and distal placers associated with the Ural-Alaskan type clinopyroxenite-dunite massifs were studied. The Isovsko-Turinskaya placer system is unique regarding its size, and was chosen as research object as it is PGM-bearing for more than 70 km from its lode source, the Ural-Alaskan type Svetloborsky massif, Middle Urals. Lode chromite-platinum ore zones located in the Southern part of the dunite “core” of the Svetloborsky massif are considered as the PGM lode source. For the studies, PGM concentrates were prepared from the heavy concentrates which were sampled at different distances from the lode source. Eluvial placers are situated directly above the ore zones, and the PGM transport distance does not exceed 10 m. Travyanistyi proximal placer is considered as an example of alluvial ravine placer with the PGM transport distance from 0.5 to 2.5 km. The Glubokinskoe distal placer located in the vicinity of the Is settlement are chosen as the object with the longest PGM transport distance (30–35 km from the lode source). Pt-Fe alloys, and in particular, isoferroplatinum prevail in the lode ores and placers with different PGM transport distance. In some cases, isoferroplatinum is substituted by tetraferroplatinum and tulameenite in the grain marginal parts. Os-Ir-(Ru) alloys, erlichmanite, laurite, kashinite, bowieite, and Ir-Rh thiospinels are found as inclusions in Pt-Fe minerals. As a result of the study, it was found that the greatest contribution to the formation of the placer objects is made by the erosion of chromite-platinum mineralized zones in dunites. At a distance of more than 10 km, the degree of PGM mechanical attrition becomes significant, and the morphological features, characteristic of lode platinum, are practically not preserved. One of the signs of the significant PGM transport distance in the placers is the absence of rims composed of the tetraferroplatinum group minerals around primary Pt-Fez alloys. The sie of the nuggets decreases with the increasing transport distance. The composition of isoferroplatinum from the placers and lode chromite-platinum ore zones are geochemically similar.

Download Full-text

Bedrock platinum-group element mineralization of zonal clinopyroxenite–dunite massifs of the Middle Urals

Doklady Earth Sciences ◽

10.1134/s1028334x17100051 ◽

2017 ◽

Vol 476 (2) ◽

pp. 1147-1151 ◽

Cited By ~ 9

Author(s):

K. N. Malitch ◽

S. Yu. Stepanov ◽

I. Yu. Badanina ◽

V. V. Khiller

Keyword(s):

Platinum Group Element ◽

Group Element ◽

Middle Urals ◽

The Middle Urals ◽

Platinum Group

Download Full-text

Platinum Group Minerals from Veresovka River Deluvial Placer, Veresovoborsky Dunite–Clinopyroxenite Massif (Middle Urals)

Geology of Ore Deposits ◽

10.1134/s1075701519080117 ◽

2019 ◽

Vol 61 (8) ◽

pp. 767-781 ◽

Cited By ~ 2

Author(s):

S. Yu. Stepanov ◽

R. S. Palamarchuk ◽

D. A. Varlamov ◽

A. V. Kozlov ◽

D. A. Khanin ◽

...

Keyword(s):

Middle Urals ◽

Platinum Group Minerals ◽

Platinum Group

Download Full-text

Platinum-group minerals from placers related to the Nizhni Tagil (Middle Urals, Russia) Uralian-Alaskan-type ultramafic complex: ore-mineralogy and study of silicate inclusions in (Pt, Fe) alloys

Mineralogy and Petrology ◽

10.1007/s00710-005-0117-1 ◽

2006 ◽

Vol 87 (1-2) ◽

pp. 1-30 ◽

Cited By ~ 15

Author(s):

Z. Johan

Keyword(s):

Middle Urals ◽

Silicate Inclusions ◽

Platinum Group Minerals ◽

Ultramafic Complex ◽

Ore Mineralogy ◽

Fe Alloys ◽

Platinum Group

Download Full-text

The first results of isotopic (U-Pb, ID-TIMS) dating of individual zircon grains from dolerite dikes of the Eastern zone of the Urals

LITOSFERA ◽

10.24930/1681-9004-2020-20-2-224-230 ◽

2020 ◽

Vol 20 (2) ◽

pp. 224-230

Author(s):

V. N. Smirnov ◽

K. S. Ivanov ◽

T. V. Bayanova

Keyword(s):

Isotope Geochemistry ◽

Early Carboniferous ◽

Dynamic Mode ◽

Middle Urals ◽

Volcanic Complex ◽

The Urals ◽

Electron Multiplier ◽

The Middle Urals ◽

Eastern Zone ◽

First Results

Research subject. The article presents the results of dating two dolerite dikes differing in geochemical features from a section along the Iset river in the area of Smolinskoe settlement (the Eastern zone of the Middle Urals). Materials and methods. The dating was performed by an U-Pb ID-TIMS technique for single zircon grains using an artificial 205Pb/235U tracer in the laboratory of geochronology and isotope geochemistry of the Geological Institute of the Kola Science Centre of the Russian Academy of Sciences. The lead isotopic composition and uranium and lead concentrations were measured using a Finnigan-MAT (RPQ) seven-channel mass spectrometer in dynamic mode using a secondary electron multiplier and RPQ quadrupole in ion counting mode. Results. The dikes were dated 330 ± 3 Ma and 240 ± 2 Ma. Conclusions. The research results indicate different ages of dolerite dikes developed within the Eastern zone of the Middle Urals. The oldest of the two established age levels corresponds to the Early Carboniferous era. This fact, along with the proximity of the dolerites to the petrochemical features of the basaltoids of the Early Carboniferous Beklenischevsky volcanic complex, allows these bodies to be considered as hypabyssal comagmates of these volcanics. The youngest obtained age level – Triassic – indicates that the introduction of some dolerite dikes was associated with the final phases of the trapp formation developed rarely within the eastern outskirts of the Urals and widely further east in the foundation (pre-Jurassic basement) of the West-Siberian Plate.

Download Full-text

Tamuraite, Ir5Fe10S16, a New Species of Platinum-Group Mineral from the Sisim Placer Zone, Eastern Sayans, Russia

Minerals ◽

10.3390/min11050545 ◽

2021 ◽

Vol 11 (5) ◽

pp. 545

Author(s):

Andrei Y. Barkov ◽

Nadezhda D. Tolstykh ◽

Robert F. Martin ◽

Andrew M. McDonald

Keyword(s):

National Laboratory ◽

X Ray Diffraction ◽

Calculated Density ◽

Cell Parameters ◽

Reflected Light ◽

Platinum Group Minerals ◽

Platinum Group ◽

Probable Space ◽

Layered Complex ◽

Residual Melt

Tamuraite, ideally Ir5Fe10S16, occurs as discrete phases (≤20 μm) in composite inclusions hosted by grains of osmium (≤0.5 mm across) rich in Ir, in association with other platinum-group minerals in the River Ko deposit of the Sisim Placer Zone, southern Krasnoyarskiy Kray, Russia. In droplet-like inclusions, tamuraite is typically intergrown with Rh-rich pentlandite and Ir-bearing members of the laurite–erlichmanite series (up to ~20 mol.% “IrS2”). Tamuraite is gray to brownish gray in reflected light. It is opaque, with a metallic luster. Its bireflectance is very weak to absent. It is nonpleochroic to slightly pleochroic (grayish to light brown tints). It appears to be very weakly anisotropic. The calculated density is 6.30 g·cm−3. The results of six WDS analyses are Ir 29.30 (27.75–30.68), Rh 9.57 (8.46–10.71), Pt 1.85 (1.43–2.10), Ru 0.05 (0.02–0.07), Os 0.06 (0.03–0.13), Fe 13.09 (12.38–13.74), Ni 12.18 (11.78–13.12), Cu 6.30 (6.06–6.56), Co 0.06 (0.04–0.07), S 27.23 (26.14–27.89), for a total of 99.69 wt %. This composition corresponds to (Ir2.87Rh1.75Pt0.18Ru0.01Os0.01)Σ4.82(Fe4.41Ni3.90Cu1.87Co0.02)Σ10.20S15.98, calculated based on a total of 31 atoms per formula unit. The general formula is (Ir,Rh)5(Fe,Ni,Cu)10S16. Results of synchrotron micro-Laue diffraction studies indicate that tamuraite is trigonal. Its probable space group is R–3m (#166), and the unit-cell parameters are a = 7.073(1) Å, c = 34.277(8) Å, V = 1485(1) Å3, and Z = 3. The c:a ratio is 4.8462. The strongest eight peaks in the X-ray diffraction pattern [d in Å(hkl)(I)] are: 3.0106(26)(100), 1.7699(40)(71), 1.7583(2016)(65), 2.7994(205)(56), 2.9963(1010)(50), 5.7740(10)(45), 3.0534(20)(43) and 2.4948(208)(38). The crystal structure is derivative of pentlandite and related to that of oberthürite and torryweiserite. Tamuraite crystallized from a residual melt enriched in S, Fe, Ni, Cu, and Rh; these elements were incompatible in the Os–Ir alloy that nucleated in lode zones of chromitites in the Lysanskiy layered complex, Eastern Sayans, Russia. The name honors Nobumichi Tamura, senior scientist at the Advanced Light Source of the Lawrence Berkeley National Laboratory, Berkeley, California.

Download Full-text