Mineralogical attributes and causes of high-pressure crystallization of Li-F granites

Abstract

Mineralogical indications of high-pressure crystallization of Li-F granites from Russia, Kazakhstan, and Mongolia are discussed. Syngenetic deformation of minerals (protoclasis) in these rocks has been revealed and described for the first time. A possible cause of the effect of high pressure on the solid phase during its crystallization from melt is considered. A progressive increase in pressure and manifestation of fluid overpressure in the course of crystallization is established. It is suggested that the idea of overpressure stated by V.S. Sobolev and N.L. Dobretsov may be applied to rare-metal magmatism.