scholarly journals Paragenesis of multiple platinum-group mineral populations in Shetland ophiolite chromitite: 3D X-ray tomography and in situ Os isotopes

2017 ◽  
Vol 216 ◽  
pp. 314-334 ◽  
Author(s):  
H.M. Prichard ◽  
Stephen J. Barnes ◽  
C.W. Dale ◽  
B. Godel ◽  
P.C. Fisher ◽  
...  
Keyword(s):  
Platinum Group Mineral ◽  
Group Mineral ◽  
X Ray ◽  
Os Isotopes ◽  
Platinum Group

Nipalarsite, Ni8Pd3As4, a new platinum-group mineral from the Monchetundra Intrusion, Kola Peninsula, Russia

2019 ◽  
Vol 83 (6) ◽  
pp. 837-845 ◽  
Author(s):  
Tatiana L. Grokhovskaya ◽  
Oxana V. Karimova ◽  
Anna Vymazalová ◽  
František Laufek ◽  
Dmitry A. Chareev ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Empirical Formula ◽  
Layered Intrusion ◽  
Mean Value ◽  
Platinum Group Mineral ◽  
X Ray Diffraction ◽  
Wavelength Dispersive Spectroscopy ◽  
Group Mineral ◽  
X Ray ◽  
Platinum Group

AbstractNipalarsite, Ni8Pd3As4, is a new platinum-group mineral discovered in the sulfide-bearing orthopyroxenite of the Monchetundra layered intrusion, Kola Peninsula, Russia (67°52′22″N, 32°47′60″E). Nipalarsite forms anhedral grains (5–80 µm in size) in intergrowths with sperrylite, kotulskite, hollingworthite, isomertieite, menshikovite, palarstanide, nielsenite and monchetundtraite enclosed in pentlandite, anthophyllite, actinolite and chlorite. Nipalarsite is brittle, has a metallic lustre and a grey streak. In plane-polarised light, nipalarsite is light grey with a blue tinge. Reflectance values in air (in %) are: 46.06 at 470 nm, 48.74 at 546 nm, 50.64 at 589 nm and 54.12 at 650 nm. Values of VHN20 fall between 400.5 and 449.2 kg.mm–2, with a mean value of 429.9 kg.mm–2, corresponding to a Mohs hardness of ~4. The average result of 27 electron microprobe wavelength dispersive spectroscopy analyses of nipalarsite is (wt.%): Ni 44.011, Pd 28.74, Fe0.32, Cu 0.85, Pt 0.01, Au 0.05, As 25.42, Sb 0.05, Te 0.39, total 99.85. The empirical formula (normalised to 15 atoms per formula unit) is: (Ni8.10Fe0.06)Σ8.16(Pd2.94Cu0.18)Σ3.12(As3.68Te0.03)Σ3.71 or, ideally, Ni8Pd3As4. Nipalarsite is cubic, space group Fm$\bar{3}$m, with a = 11.4428(9) Å, V = 1498.3(4) Å3 and Z = 8. The strongest lines in the powder X-ray diffraction pattern of synthetic Ni8Pd3As4 [d, Å (I) (hkl)] are: 2.859(10)(004), 2.623(6)(313), 2.557(6)(024), 2.334(11)(224), 2.201(35)(115,333), 2.021(100)(044), 1.906(8)(006,244) and 1.429(7)(008). The crystal structure was solved and refined from the single-crystal X-ray diffraction data of synthetic Ni8Pd3As4. The relation between natural and synthetic nipalarsite is illustrated by an electron back-scattered diffraction study of natural nipalarsite. The density calculated on the basis of the empirical formula of nipalarsite is 9.60 g.cm–3. The mineral name corresponds to the three main elements: Ni, Pd and As.

scholarly journals Fleetite, Cu2RhIrSb2, a New Species of Platinum-Group Mineral from the Miass Placer Zone, Southern Urals, Russia

2021 ◽  
Author(s):  
Andrei Y. Barkov ◽  
Luca Bindi ◽  
Nobumichi Tamura ◽  
Robert F. Martin ◽  
Chi Ma ◽  
...  
Keyword(s):  
New Species ◽  
Fluid Phase ◽  
Southern Urals ◽  
Platinum Group Mineral ◽  
Calculated Density ◽  
Group Mineral ◽  
X Ray ◽  
Wavelength Dispersive Spectrometry ◽  
Platinum Group ◽  
A New Species

ABSTRACT Fleetite, Cu2RhIrSb2, a new species of platinum-group mineral (PGM), was discovered intergrown with an Os–Ir–Ru alloy in the Miass Placer Zone (Au–PGE), southern Urals, Russia. A single grain 50 μm across was found. Osmium, ruthenium, and iridium are the main associated minerals; also present are Pt–Fe alloys, laurite, Sb-rich irarsite, Rh-rich tolovkite, kashinite, anduoite, ferronickelplatinum, heazlewoodite, PGE-bearing pentlandite and digenite, as well as micrometric inclusions of forsterite (Fo93.7), chromite–magnesiochromite, and Mg-rich edenite. In reflected light, fleetite is light gray; it is opaque, isotropic, non-pleochroic, and non-bireflectant. We report reflectance values measured in air. A mean of seven point-analyses (wavelength-dispersive spectrometry) gave Cu 13.93, Ni 8.60, Fe 0.10, Ir 28.07, Rh 7.91, Ru 1.96, Sb 39.28, total 99.85 wt.%, corresponding to (Cu1.41Ni0.58Fe0.01)Σ2.00(Rh0.49Ni0.36Ru0.12)Σ0.97Ir0.95Sb2.08 on the basis of six atoms per formula unit, taking into account the structural results. The calculated density is 10.83 g/cm3. Single-crystal X-ray studies show that fleetite is cubic, space group Fdm (#227), a = 11.6682(8) Å, V = 1588.59(19) Å3, and Z = 16. A least-squares refinement of X-ray powder-diffraction data gave a = 11.6575(5) Å and V = 1584.22(19) Å3. The strongest five reflections in the powder pattern [d in Å(I)(hkl)] are: 6.70(75)(111), 4.13(100)(220), 3.52(30)(311), 2.380(50)(422), 2.064(40)(440). Results of synchrotron micro-Laue diffraction experiments are consistent [a = 11.66(2) Å]. The crystal structure of fleetite was solved and refined to R = 0.0340 based upon 153 reflections with Fo > 4σ(Fo). It is isotypic with Pd11Bi2Se2 and best described as intermetallic, with all metal atoms in 12-fold coordination. Fleetite and other late exotic phases were formed by reaction of the associated alloy phases with a fluid phase enriched in Sb, As, and S in circulation in the cooling ophiolite source-rock. The mineral is named after Michael E. Fleet (1938–2017) in recognition of his significant contributions to the Earth Sciences.

Platinum-group mineral characterisation in concentrates from low-grade PGE chromitites from the Vourinos ophiolite complex, northern Greece

2006 ◽  
Vol 115 (2) ◽  
pp. 49-57 ◽  
Author(s):  
A. Kapsiotis ◽  
T. A. Grammatikopoulos ◽  
F. Zaccarini ◽  
B. Tsikouras ◽  
G. Garuti ◽  
...  
Keyword(s):  
Platinum Group Mineral ◽  
Low Grade ◽  
Northern Greece ◽  
Ophiolite Complex ◽  
Group Mineral ◽  
Platinum Group

Biological role in the transformation of platinum-group mineral grains

2016 ◽  
Vol 9 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Frank Reith ◽  
Carla M. Zammit ◽  
Sahar S. Shar ◽  
Barbara Etschmann ◽  
Ralph Bottrill ◽  
...  
Keyword(s):  
Platinum Group Mineral ◽  
Biological Role ◽  
Group Mineral ◽  
Platinum Group

The role of dithiophosphate as a co-collector in the flotation of a platinum group mineral ore

2012 ◽  
Vol 36-38 ◽  
pp. 100-104 ◽  
Author(s):  
K.C. Corin ◽  
J.C. Bezuidenhout ◽  
C.T. O’Connor
Keyword(s):  
Platinum Group Mineral ◽  
Group Mineral ◽  
Platinum Group

Platinum-group mineral assemblages in the Platreef at the Sandsloot Mine, northern Bushveld Complex, South Africa

2006 ◽  
Vol 70 (1) ◽  
pp. 83-101 ◽  
Author(s):  
D. A. Holwell ◽  
I. McDonald ◽  
P. E. B. Armitage
Keyword(s):  
Small Volume ◽  
Bushveld Complex ◽  
Rock Type ◽  
Platinum Group Mineral ◽  
Main Zone ◽  
Group Mineral ◽  
Multi Stage ◽  
Mineral Assemblages ◽  
Base Metal Sulphides ◽  
Platinum Group

AbstractPlatinum group mineral (PGM) assemblages in the Platreef at Sandsloot, northern Bushveld Complex, in a variety of lithologies reveal a complex multi-stage mineralization history. During crystallization of the Platreef pyroxenites, platinum group elements (PGE) and base-metal sulphides (BMS) were distributed thoughout the interstitial liquid forming a telluride-dominant assemblage devoid of PGE sulphides. Redistribution of PGE into the metamorphic footwall by hydrothermal fluids has formed arsenide-, alloy- and antimonide-dominant assemblages, indicating a significant volatile influence during crystallization. Serpentinization of the footwall has produced an antimonide-dominant PGM assemblage. Parts of the igneous reef were subjected to alteration by a late-stage, Fe-rich fluid, producing ultramafic zones where the telluride-dominant assemblage has been recrystallized to an alloy-dominant one, particularly rich in Pt-Fe and Pd-Pb alloys. A thin, small-volume zone of PGE-BMS mineralization along the base of the hangingwall contains a primary PGM assemblage that is locally altered to one dominated by Pt/Pd germanides. This is thought to have formed when the new pulse of Main Zone magma entered the chamber, and scavenged PGE from the underlying Platreef pyroxenites. That each major rock type at Sandsloot contains a distinctive PGM assemblage reflects the importance of syn- and post-emplacement fluid and magmatic processes on the development of Platreef mineralization.

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