Аннотация:Organic substances (OS) are usual components of peralkaline pegmatites. OS can form macroscopic segregations growing on microporous hetero-framework zeolite-like silicates with Ti, Nb or Zr (playing the role of catalysts of OS formation), or intergrowths with minerals of REE, Th, U. The formation of OS is possible only under reductive conditions arising after mass crystallization of aegirine. Oxygen-bearing aromatic substances act as complexing agents towards Th, REE, U, Zr, Ti, Nb and facilitate transportation of these elements under low-temperature hydrothermal conditions in the form of water-soluble associates. Microheterogeneous aggregates with OS can contain alkaline-earth and other elements in the form of carboxylate salts M2+(ArCOO-)2 (where Ar is a polycyclic aromatic radical; M = Ca, Sr, Ba, Pb, REE) and microscopic inclusions of mineral phases with Th, U, REE, Nb, Ti. OS from peralkaline pegmatites of Khibiny and Lovozero massifs (Kola peninsula) have been investigated using IR spectroscopic, electron microprobe and X-ray powder diffraction. Separation of Y (+HREE), Ce, La, Nd, Th and U between organic and different mineral phases is an important distinctive feature of microheterogeneous aggregates with OS from in peralkaline pegmatites, and an important cause for unusual mineral diversity in these formations.
