Trap formation of the Kola peninsula

Abstract

The nepheline syenites and foidolites of the world’s largest Lovozero and Khibiny allkaline massifs contain numerous xenoliths of intercalating olivine basalts, their tuffs, tuffites, and quartzitosandstones that experienced more (in the Khibiny Massif) or less (in the Lovozero Massif) intense thermal-metasomatic transformation. In terms of geological, petrographical, and petrochemical features, the unaltered rocks of the Lovozero Formation can be ascribed to the rocks of the trap formation, while all wealth of the rocks formed during their contact-metasomatic alteration (sekaninaite-anorthoclase, annite-anorthoclase, fayalite-anorthoclase, rutile-freudenbergite-anorthoclase, topaz-andalusite-anorthoclase, and others) was formed due to alkaline metasomatism. The Fourier analysis of the color variation curves for the volcanogenic-sedimentary rocks revealed the identity between bedding of initial tuffs (tuffites) and banding of their fenitized analogues.