Abstract

Biotite has been studied extensively and is often used to compare, classify magmas, determine the formation temperature, pressure, determine the phase and formation, determine the acid-base regime of the environment, the origin of the rock and the geochemical conditions of mineral formation. Biotite of Song Hinh massif belongs to the annite - siderophyllite series rich in Fe, high in Mg. According to the composition of biotite in them, the massif was formed at temperatures from 736 to 769°C with an average of 752oC±12°C and at pressure from 1.95 to 2.74 kbar with an average of 2.22 ± 0.68 kbar, corresponding to a depth of ~ 6.63km. Granite of Song Hinh massif belongs to type I-granite. Biotite in the massif is poor in Cl and F, according to mineralization they belong to type-II: Water type, Granitoid related to North American porphyry copper mines, with Au, Cu, Pb, Zn mineralization.