Вестник МГТУ, 2021, Т. 24, № 1.

Вестник МГТУ. 2021. Т. 24, № 1. С. 80-87. DOI: https://doi.org/10.21443/1560-9278-2021-24-1-80-87 Introduction The Kola Alkaline Province (KAP) is one of the largest alkaline-carbonatite associations with more than 30 massifs occupying the Kola region, northern Karelia and Finland (Fig. 1). The main stage of alkaline igneous activity in the north-eastern part of the Fennoscandian Shield was marked by the biggest agpaitic complexes of Khibina and Lovozero with numerous carbonatite intrusions of Kovdor, Sokli, Afrikanda, Turiy Mys which were formed in Late Devonian, at 365-370 Ma. The Khibina apatite-nepheline deposits with Lovozero REE commercial mineralization make a great contribution to the mineral resource base of the Arctic zone of the Russian Federation. Geophysical and geological data based on a prospecting drilling program give evidence for significant differences in the internal structure of two giant polyphase magmatic bodies, and commercial mineralization enclosed in these intrusions (Kramm et al., 1993; Kogarko et al., 2019). The Khibina massif is a dome-shaped mountain massif, situated in the central part of the Kola Peninsula. It's located within Archaean gneisses and Proterozoic Pechenga-Imandra-Varzuga palaeoriftogenic volcanic- sedimentary complexes (Fig. 1). In the Khibina massif, peralkaline K-Na and K nepheline syenites are intercalated with the members of the typical ultrabasic-alkaline and carbonatite series. The Khibina massif is a concentrically zoned multiphase intrusion composed of agpaitic nepheline syenites and in a minor amount of ultrabasic alkaline rocks. The zone of fenitized rocks extends for 50-200 m. Numerous nepheline syenite veins and alkaline pegmatites penetrated the country rocks at a distance of more than 100 m from the contact (Arzamastsev et al., 2008). Fig. 1. Scheme of the locations of Kola Alkaline Province intrusions (Arzamastsev et al., 2008): 1 - Khibina; 2 - Lovozero; 3 - Niva; 4 - Mavraguba; 5 - Kovdor; 6 - Sokli; 7 - Sallanlatva; 8 - Vuoriyarvi; 9 - Kandaguba; 10 - Afrikanda; 11 - Ozernaya Varaka; 12 - Lesnaya Varaka; 13 - Salmagora; 14 - Ingozero; 15 - Turiy Mys; 16 - Kurga; 17 - Kontozero; 18 - Ivanovka; 19 - Seblyavr; 20 - Pesochny Рис. 1. Схема расположения интрузий Кольской щелочной провинции (Arzamastsev et al., 2008): 1 - Хибины; 2 - Ловозеро; 3 - Нива; 4 - Маврагуба; 5 - Ковдор; 6 - Сокли; 7 - Салланлатва; 8 - Вуориярви; 9 - Кандагуба; 10 - Африканда; 11 - Озерная варака; 12 - Лесная варака; 13 - Салмагора; 14 - Ингозеро; 15 - Турий Мыс; 16 - Курга; 17 - Контозеро; 18 - Ивановка; 19 - Себлъявр; 20 - Песочный 81