New geochronometer for the direct isotopic dating of native platinum minerals (190Pt-4He method)

Shukolyukov, Yu. A.; Yakubovich, O. V.; Mochalov, A. G.; Котов, А. Б.; Сальникова, Е. Б.; Yakovleva, S. Z.; Korneev, S. I.; Gorokhovskii, B. M.

doi:10.1134/s0869591112060033

Cited by 31 publications

(20 citation statements)

References 26 publications

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“…In the placer bedrock, among the weathered and fissured rocks of the massif, higher quantities of platinum grains are found. The age (112 ± 7 Ma) of the placer ferroplatinum (Shukolyukov et al, 2012) agrees with the age of the platinum-bearing dunite as determined by U-Pb dating of baddeleyite and zircon (124.9 ± 1.9 Ma and 125.8 ± 3.8 Ma, respectively; Ronkin et al, 2013).…”

Section: Late Mesozoic Ore Depositsmentioning

confidence: 82%

Geodynamics of late Mesozoic PGE, Au, and U mineralization in the Aldan shield, North Asian Craton

Хомич

Santosh

2015

Ore Geology Reviews

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Section: Late Mesozoic Ore Depositsmentioning

confidence: 82%

Geodynamics of late Mesozoic PGE, Au, and U mineralization in the Aldan shield, North Asian Craton

Хомич

Santosh

2015

Ore Geology Reviews

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“…Massive to semi-massive sulfide ores are located at two levels from the present surface, 130-380 m (bodies Nos. 1,5,6,9) and 420-640 m (bodies Nos. 2-4, 7, 8) with 300-350 m between the levels (Figure 3).…”

Section: Geological Settingmentioning

confidence: 99%

“…This approach avoids contamination of the sample with the material of the extractor of the mass spectrometer and also saves the sample for further determination of U and Th. Details of the He measurement technique and the design of the instrument are described in References [5,102]. The complete procedural blank determined by heating the empty ampoule in the Re cuvette to 1100 • C corresponds to~5 × 10 −10 cm 3 STP, whereas the detection limit of the instrument is~5 × 10 −13 cm 3 STP of 4 He.…”

Section: Measurement Of Radiogenic 4 He Contentsmentioning

confidence: 99%

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U-Th-He Geochronology of Pyrite from the Uzelga VMS Deposit (South Urals)—New Perspectives for Direct Dating of the Ore-Forming Processes

et al. 2020

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We report on the application of the U-Th-He method for the direct dating of pyrite and provide an original methodological approach for measurement of U, Th and He in single grains without loss of parent nuclides during thermal extraction of He. The U-Th-He age of ten samples of high-crystalline stoichiometric pyrite from unoxidized massive ores of the Uzelga volcanogenic massive sulfide (VMS) deposit, South Urals, is 382 ± 12 Ma (2σ) (U concentrations ~1–5 ppm; 4He ~10−4 cm3 STP g−1). This age is consistent with independent (biostratigraphic) estimations of the age of ore formation (ca, 389–380 Ma) and is remarkably older than the probable age of the regional prehnite-pumpellyite facies metamorphism (~340–345 Ma). Our results indicate that the U-Th-He dating of ~1 mg weight pyrite sample is possible and open new perspectives for the dating of ore deposits. The relative simplicity of U-Th-He dating in comparison with other geochronological methods makes this approach interesting for further application.

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“…This allowed elaboration of a new 190 Pt- 4 He method of isotope geochronology for direct determination of the age of platinum mineralization [2].…”

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confidence: 99%

Sperrylite (PtAs2) as a 190Pt-4He geochronometer

2015

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The mineral sperrylite (PtAs2), unlike other Pt minerals, has shown to be resistant to cyanide leaching, even at elevated temperatures of 50°C. This has prevented further development of a two-stage heap leaching process, of which the second stage is cyanide leaching for a Platreef ore, due to a considerable portion of the Pt being present as sperrylite. Through a comprehensive set of leaching tests, this study has shown that sperrylite leaches slowly in cyanide due to eventual passivation. The addition of ferricyanide to the cyanide solution results in significantly more Pt being leached (up to 16 times) than with cyanide only under identical process conditions. However, over time passivation occurred in this system also, but can be seemingly be overcome by filtering, rinsing and re-suspending the sperrylite. This was further investigated using a reactor system continuously fed with a ferricyanide-cyanide to leach a fixed bed of sperrylite mineral. Again, gradual passivation of the mineral phase was observed, which was fully reversible following a day of feeding with distilled water. XPS analysis of fresh and leached mineral indicated a depletion of As on the mineral surface, which tallied with an observed preferential leaching of As during leaching, at least initially. As a result, it is postulated that a less cyanide-soluble compound of the form PtAs(X) forms, where x is less than 2. The ease with which the leaching process can be restarted after rinsing the mineral indicates that the adsorption of solution species is the key step in forming a passivating layer. This adsorption is potentially favoured by the gradual surface transformation. Finally, an electrochemical study confirmed that the ferricyanide-cyanide system facilitated an electron transfer reaction at the sperrylite surface with the likely oxidation of As and reduction of the ferricyanide. Gradual passivation of the surface was also observed in this system.

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New geochronometer for the direct isotopic dating of native platinum minerals (190Pt-4He method)

Cited by 31 publications

References 26 publications

Geodynamics of late Mesozoic PGE, Au, and U mineralization in the Aldan shield, North Asian Craton

Geodynamics of late Mesozoic PGE, Au, and U mineralization in the Aldan shield, North Asian Craton

U-Th-He Geochronology of Pyrite from the Uzelga VMS Deposit (South Urals)—New Perspectives for Direct Dating of the Ore-Forming Processes

Sperrylite (PtAs2) as a 190Pt-4He geochronometer

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