MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF PGE-Cu-Ni ORES OF THE MASLOVSKY DEPOSIT IN THE NORIL'SK AREA, RUSSIA

We present new results on the geochemistry and mineralogy of the disseminated ores from the Maslovsky deposit, Noril’sk area, Russia. On the basis of the composition of rocks and of the rock-forming minerals, the deposit consists of two magmatic bodies: the northern one is a continuation of the Noril’sk-1 intrusion, whereas the southern one represents a separate massif. The disseminated ores from these two intrusions have distinctive differences: the Pd:Pt ratio of the northern ores is in the range 5–6, and Ni:Cu is in the range 2–16, whereas in the southern ores, these values are close to 1. The precious metal mineralogy of the disseminated ores reflects their chemical differences. The main PGM of the northern deposit are zvyagintsevite, atokite– rustenburgite and Fe–Pt alloys, whereas Au–Ag and Fe–Pt alloys are typical for the southern part of the deposit. The ore geochemistry and PGM composition of northern part of the Maslovsky deposit is similar to those of the Noril’sk-1 deposit. Calculations of weighted mean compositions (data from cores OM–4, OM–24 and MS–31) show that there is no correlation between ore and rock compositions for these three deposits.