Tourmaline Supergroup Minerals from Rare-Metal Pegmatites of the Voron’ya Tundra (Kola Peninsula, Russia)

Abstract

Study data on dark-colored, bright, and pale pink tourmalines of rare-metal pegmatites from Mt. Okhmylk in the Voron’ya Tundra region are reported. Chemical compositions and parameters of elementary cells are determined for tourmalines. Dark-colored tourmaline I is schörl–olenite, and pink tourmaline corresponds to elbaite–olenite. Studied tourmalines and tourmalines from spodumene pegmatites of other regions are compared. Based on the rare-earth element distribution in tourmalines, they are suggested to have been formed with involvement of high-temperature postmagmatic solutions. Mineral inclusions in schörl–olenite are represented by biotite and magnetite. Mineral inclusions in elbaite–olenite are cassiterite, pollucite, apatite, and tantalite. Tantalite is characterized by higher tantalum and low niobium. In addition, pure manganotantalite is often present in elbaite–olenite, and simpsonite is always observed at contacts between tantalite inclusions and tourmaline. All these data are indicative that albite–spodumene pegmatites of this region were formed with an active role of metasomatic processes.