Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2021

Идентификатор DOI: 10.3390/min11111193

Ключевые слова: base metal sulfides, basic-ultrabasic rocks, fluids enriched in chlorine, norilsk complex, oktyabrsky deposit, pd-pt and au-ag mineralization, platinum group minerals, ree, russia, u and th mineralization, y, zr

Аннотация: Highly atypical mineralization involving Pd-Pt, Au-Ag, REE, Y, Zr, U, Th, and Cl-F-enriched minerals is found in zones with base metal sulfides (BMS; ~5 vol.% to 20 vol.%) in the eastern portion of the Oktyabrsky deposit in the Norilsk complex (Russia). The overall variations in Mg# index, 100 Mg/(Mg + Fe2+ + Mn), in host-rock minerals are 79.8 → 74.1 in olivine, 77.7 → 65.3 in orthopyroxene, 79.9 → 9.2 in clinopyroxene, and An79.0 → An3.7 . The span of clinopyroxene and plagioclase compositions reflects their protracted crystallization from early magmatic to late interstitial associations. The magnesian chromite (Mg# 43.9) trends towards Cr-bearing magnetite with progressive buildups in oxygen fugacity; ilmenite varies from early Mg-rich to late Mn-rich variants. The main BMS are chalcopyrite, pyrrhotite, troilite, and Co-bearing pentlandite, with less abundant cubanite (or isocubanite), rare bornite, Co-bearing pyrite, Cd-bearing sphalerite (or wurtzite), altaite, members of the galena-clausthalite series and nickeline. A full series of Au-Ag alloy compositions is found with minor hessite, acanthite and argentopentlandite. The uncommon assemblage includes monazite-(Ce), thorite-coffinite, thorianite, uraninite, zirconolite, baddeleyite, zircon, bastnäsite-(La), and an unnamed metamict Y-dominant zirconolite-related mineral. About 20 species of PGM (plat-inum group minerals) were analyzed, including Pd-Pt tellurides, bismuthotellurides, bismuthides and stannides, Pd antimonides and plumbides, a Pd-Ag telluride, a Pt arsenide, a Pd-Ni arsenide, and unnamed Pd stannide-arsenide, Pd germanide-arsenide and Pt-Cu arseno-oxysulfide. The atypical assemblages are associated with Cl-rich annite with up to 7.54 wt.% Cl, Cl-rich hastingsite with up 4.06 wt.% Cl, ferro-hornblende (2.53 wt.% Cl), chlorapatite (>6 wt.% Cl) and extensive solid solutions of chlorapatite, fluorapatite and hydroxylapatite, Cl-bearing members of the chlorite group (chamosite; up to 0.96 wt.% Cl), and a Cl-bearing serpentine (up to 0.79 wt.% Cl). A decoupling of Cl and F in the geochemically evolved system is evident. The complex assemblages formed late from Cl-enriched fluids under subsolidus conditions of crystallization following extensive magmatic differentiation in the ore-bearing sequences. © 2021 by the authorsLicensee MDPI, Basel, Switzerland.

Журнал: Minerals

Выпуск журнала: Vol. 11, Is. 11

Номера страниц: 1193

ISSN журнала: 2075163X

Издатель: MDPI

• Barkov Andrei Y. (Cherepovets State Univ, Res Lab Ind & Ore Mineral, 5 Lunacharsky Prospect, Cherepovets 162600, Russia)
• Nikulin Ivan I. (Norilskgeologiya OOO, 11 Grazhdansky Prospect, St Petersburg 195220, Russia)
• Nikiforov Andrey A. (Cherepovets State Univ, Res Lab Ind & Ore Mineral, 5 Lunacharsky Prospect, Cherepovets 162600, Russia)
• Lobastov Boris M. (Siberian Fed Univ, Inst Min Geol & Geotechnol, 79 Svobodny Prospect, Krasnoyarsk 660041, Russia)
• Silyanov Sergey A. (Siberian Fed Univ, Inst Min Geol & Geotechnol, 79 Svobodny Prospect, Krasnoyarsk 660041, Russia)
• Martin Robert F. (McGill Univ, Dept Earth & Planetary Sci, 3450 Univ St, Montreal, PQ H3A 0E8, Canada)

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