THE FEATURES OF KOLA ALKALINE PROVINCE

In the NE part of the Fennoscandian Shield there are 24 known alkaline intrusions, regional and local alkaline dike series, eruptive breccia s and alkaline effusive relics. The Kola province is distinguishable d ue to the presence to two world's largest massifs composed mainly of a gpaitic nepheline syenite: the Khibiny and Lovozero massifs located in the center of the Kola peninsula. The oldest intrusions are represent ed by syenite associated with peralkaline granite and gabbroids. These were followed by lower Proterozoic alkaline-gabbroid massifs (Gremyak ha-Vyrmes and Yelety-ozero). The most abundant are the lower Paleozoic (360-400 Ma) alkaline-ultrabasic massifs. The Khibiny and Lovozero pl utons were also developed at that time. Numerous data on Sr-87/Sr-86 r atios measured in apatite from various silicate rocks and carbonatites suggest a deep-seated source for the alkaline intrusions. The alkalin e massifs are confined to the boundaries of Precambrian blocks and to repeatedly appearing deep faults. The distance being about 7 km betwee n them, the Khibiny and Lovozero massifs occur in the jointing zone of three Precambrian blocks and on the intersection point of regional te ctonic zones of the Paleozoic activity of the Shield. The location and the size of the Khibiny-Lovozero complex lead to the hypothesis of it s development at an early stage of the continental rifting which was n ot completed. Alkaline platform massifs of the Kola peninsula contain the rocks confirming occurrence of the late-stage differentiation of t he matter. Big Ti, Fe, Al, K, P deposits are composed either of rocks similar to monomineral ones or to those containing polycrystalline mon omineral aggregates. The geochemical features of province are P, Zr, N b, Sr, and REE concentrations and the best diversity of agpaitic miner alization (Khibiny, Lovozero). Although the Khibiny apatites deposit a re very distinctive, their presence in the massif is in a good agreeme nt with the empirical data: Khibiny is the Paleozoic massif including the carbonatites and foidolites with deep differentiation of the nephe line magmas.