Pegmatoid schlieren with tourmaline in granitoids of eastern russia as an attribute of intrusive series completed by ore-bearing Li-F granites

摘要

Tourmaline schlieren in pegmatoids and host granites are widespread in Cretaceous granitoid plutons occurring in tin districts of eastern Russia. These schlieren were formed under the action of fluoricboron fluids, which are considered to be forerunners of rare-metal granite magmatism. The tourmaline schlieren in adamellites, biotite, and two-mica granites are reliable attributes of intrusive series completed by emplacement of ore-bearing Li-F granites.