Two Types of Highly Differentiated Topaz-Bearing Granites of the Salmi Batholith, Southern Karelia

Differences between two types of highly differentiated granites of the Salmi batholith: namely Li-siderophyllite topaz-bearing and Li-F topaz-zinnwaldite granites, were determined based on the study of their structural-morphological, mineralogical and geochemical features are determined. The high degree of the differentiation of these granites is confirmed by the presence of primary topaz, Li-micas of magmatic origin and by the presence of significative tetrad effect of M type. These granites are distinguished due to the types of their micas, the content of topaz (up to 1 and 15%, respectively), the morphology of granite intrusions and the geochemistry of rare elements. The Li-F zinnwaldite granites are depleted in REE and enriched in Ta, Hf, Ba, Sr compared to the Li-siderophyllite granites. The Li-siderophyllite granites clearly fit to the general evolution trend of the Salmi batholith granites, while the genesis of Li-F zinnwaldite granites seems to be associated not only with the processes of crystallization differentiation of the melt but also with the active addition of some components, primarily F and Li, probably from a deeper source, including the mantle.