TO THE ONTOGENESIS OF AESCHYNITE IN FELDSPAR VEIN NO. 31 OF THE VISHNEVYE GORY, SOUTH URALS

Abstract

Small grains of accessory aeschynite in feldspar vein no. 31 of Vishnevye Mountains (South Urals) co-crystallize with late growth zones of feldspar crystals, as well as with ilmenite, titanomagnetite, muscovite, zircon, monazite, thorite, rutile, columbite and other minerals. Crystallization of aeschynite was followed by its metamict decay and formation of a nanocrystalline structure and further repeated dissolution and metasomatosis along microfractures of the mineral aggregate. Metasomatosis of aeschynite was accompanied by the formation of microporosity in muscovite-ilmenite aggregates at the contact with aeschynite grains.

Keywords

• aeschynite
• paragenesis
• ontogenesis
• metamict decay
• metasomatism
• microporosity
• feldspar pegmatites