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New Evidence of the Polycyclic Genesis of Platinum Placer-Forming Formations of the Kondyor Alkaline-Ultramafic Massif: Results of 190Pt–4He Dating.
- Source :
- Doklady Earth Sciences; May2021, Vol. 498 Issue 1, p372-378, 7p
- Publication Year :
- 2021
-
Abstract
- This article presents the <superscript>190</superscript>Pt–<superscript>4</superscript>He dating results of native platinum group minerals from a unique platinum-metals placer deposit in the basin of the Kondyor and Uorgalan rivers and dunite fragments from the Kondyor alkaline-ultramafic massif. The results of <superscript>190</superscript>Pt–<superscript>4</superscript>He dating of 75 samples determine the age of the minerals and also date the ore-forming processes. It confirms the previously developed model of polycyclic genesis of placer-forming formations of platinum group minerals (PGMs) and, thus, sheds light on the duration of the formation of the Kondyor alkaline-ultramafic massif. The following <superscript>190</superscript>Pt–<superscript>4</superscript>He age stages are distinguished: (a) 143 ± 7 Ma, the formation time of the massif itself and early formation stages of PGMs of magmatogenic platinum (Pt) and the magmatogenic–fluid–metasomatic Pt and Os–Pt (Pt > Os) types, as well as PGMs of fluid-metamorphogenic iridium–platinum (Pt > Ir) type; (b) 128 ± 6 Ma, the early formation stages of the magmatogenic–fluid–metasomatic Pd–Pt (Pt > Pd) type and the late stages of the Pt, Pt > Os, and Pt > Ir types; (c) 115 ± 6 Ma, the late formation stages of the Pt > Pd type. The good agreement of these dates with the geological and mineralogical data allows us to conclude that the formation of placer-forming PGMs and their formations in the Kondyor alkaline-ultramafic massif was a polycyclic process for about 30 Ma. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1028334X
- Volume :
- 498
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Doklady Earth Sciences
- Publication Type :
- Academic Journal
- Accession number :
- 150669016
- Full Text :
- https://doi.org/10.1134/S1028334X2105010X