Вестник МГТУ, 2021, Т. 24, № 1.

Вестник МГТУ. 2021. Т. 24, № 1. С. 80-87. DOI: https://doi.org/10.21443/1560-9278-2021-24-l-80-87 Results and discussion The Khibina massive nepheline syenites have coarse-grained structure and poikilitic texture (Fig. 3, a , b). The main minerals are automorphic orthoclase, plagioclases, and apatite, among which can be found crystals of aegirine-acmite and xenomorphic crystals of eudialyte. There are also present ilmenite, titanite, magnetite, arfvedsonite, riebeckite, astrophyllite, aenigmatite and lorenzenite. Among the ore minerals it can be found the vast majority of ilmenite, titanite and magnetite. In addition there are relatively often encountered sulfide phases such as pyrite (about 4 %) and in an amount of less than 1 % - chalcopyrite, pentlandite, and arsenopyrite. Chalcozine and sphalerite are also noticed lin some samples. The sulfide phases from Khibina samples - pentlandite ((Fe, Ni)9S8, samples 01CH, 10CH) and pyrite (FeS2, sample 04CH) - show a large spread in 534S values from +0.69 to +4.92 %o VCDT. The 534S values for two analysis of pentlandite range from +0.69 to +2.06 %o, and the pyrite has significantly higher 534S values up to +4.92 %oVCDT (Table). Fig. 2. Schematic geological map of the Khibina and Lovozero massifs (Arzamastsev et al., 2011). Khibina massif: 1 - carbonatite; 2 - pulaskite; 3 - foyaite; 4 - nepheline syenite; 5 - massive rischorrite, jovite and urtite; 6 - apatite-nepheline rock; 7 - ijolite and melteigite; 8 - coarse-grained trachytoid nepheline syenite; 9 - coarse-grained massive nepheline syenite (khibinite). Lovozero massif: 10 - eudialyte lujavrite; 11 - lujavrite, foyaite and urtite of the differentiated complex; 12 - volcanic rocks of the Lovozero Formation; 13 - alkaline-ultramafic rocks. Kurga massif: 14 - nepheline syenite; 15 - peridotite. Host rocks: 16 - basaltic porphyry and dolerite (Late Proterozoic); 17 - granodiorite, tonalite, and trondhjemite (Archean); 18 - dikes of alkaline rocks. The stars indicate the sampling locations Рис. 2. Схематическая геологическая карта Хибинского и Ловозерского массивов (Arzamastsev et al., 201 1). Хибинский массив: 1 - карбонатит; 2 - пуласкит; 3 - фойяит; 4 - нефелиновый сиенит; 5 - массивные рисчоррит, ювит и уртит; 6 - апатит-нефелиновая порода; 7 - ийолит и мельтейгит; 8 - крупнозернистый трахитоидный нефелиновый сиенит; 9 - крупнозернистый массивный нефелиновый сиенит (хибинит). Ловозерский массив: 10 - эвдиалитовый луяврит; 11 - луяврит, фойяит и уртит дифференцированного комплекса; 12 - вулканические породы ловозерской свиты; 13 - щелочно- ультраосновные породы. Кургинский массив: 14 - нефелиновый сиенит; 15 - перидотит. Вмещающие породы: 16 - базальтовые порфиры и долериты (поздний протерозой); 17 - гранодиорит, тоналит и трондьемит (архей); 18 - дайки щелочных пород. Звездами показаны места отбора образцов The Lovozero eudialyte-bearing nepheline syenites are gray-green color rocks with visible red-blood crystals of eudialyte and fine-crystalline feldspars and aegirine (Fig. 3, c, d). These rocks have a coarse-grained structure and a porphyritic, linear texture. The orthoclase crystals, twinned according to the Carlsbad law, often have a very elongated form giving the rocks a linear and pseudo-ophitic structure. Between these crystals there are also albite tablets. When an interaction between the minerals occurs, one meets the needles of aegirine in the company o f ilmenite and titanomagnetite, as well as individual rutile and titanite grains. The stable sulfur isotopes analyses have been carried out on the three sulfide phases from the Lovozero samples: pentlandite ((Fe, 83