Mineralogical and geochemical feature of the disseminated ores of the southern part of the Noril'sk 1 deposit

9th All Russian petrographic conference with international participation: Petrology of magmatic and metamorphic complexes

Tolstykh, N.D.^1 ; Shvedov, G.I.^2 ; Polonyankin, A.A.^3 ; Zemlyansky, S.A.^4

VS Sobolev Institute of Geology and Mineralogy, SB RAS, Novosibirsk, Russia^1

LLC Geological Technologies, Krasnoyarsk, Russia^2

OOO Russian Platinum, Moscow, Russia^3

Open Company Novogeo, Krasnoyarsk, Russia^4

关键词: Geochemical features;    Host rocks;    Low sulfurs;    Mackinawite;    Ore forming systems;    Sulphide ores;    Topdown;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/110/1/012021/pdf
DOI  :  10.1088/1755-1315/110/1/012021

来源: IOP

【 摘 要 】

The new data on the composition of disseminated sulphide ore in the southern part of the Noril'sk 1 deposit are obtained. It was found that a sulfur-poor assemblage: as Fe-rich (cubanite, mackinawite) and Cu-rich (talnakhite, bornite, chalcocite, native copper) minerals due to the evolution of two different fractions of sulphide melt is characteristic of picritic gabbro-dolerite. It has been formed at relatively low sulfur activity (lgfS2range from -12 to -11). And a high-sulfur assemblage (monoclinic pyrrhotite, pyrite and Ni-rich pentlandite) formed at higher sulfur activity (lgfS2range from -10.5 to -10) due to the pyrrhotite-chalcopyrite fractionation of the sulphide melt is characteristic of olivine gabbro-dolerite. The ratios of Ni/Cu in the rocks decrease from picritic (Ni/Cu = 1.24 average) to olivine gabbro- dolerites (Ni/Cu = 0.69 average). But the Ni/Fe ratios in pentlandite are increasing down the cross-section due to increase of sulfur fugacity during the evolution of ore-forming system. The Pd-parageneses vary along the cross-section top down as follows: Sn → Pb → As → Bi(Te) in picritic gabbro-dolerite and Sn → Sb → As → Te(Bi) in olivine gabbro-dolerite. There is a clear correlation between the sulfide and PGM assemblage and the type of the host rocks.