Time factor in formation of metasomatic rocks, veins and veinlets constituting greisen ore deposits

The author examines greisen deposits in Kazakhstan Urals, Transbaykal region and the Lesser Khingan Range. The evolution of the process of mineral deposition is considered from the point of view of microclinization, followed by albitization and silicification, accompanied by a decrease of pH. The process of greisenization accompanies an increase of pH and is followed by the deposition of minerals containing W, Sn, Be, Si and Mo. -- E. A. Alexandrov.