Abstract
Chiêm Hóa granites are exposed as small bodies in the Chiêm Hóa district, Tuyên Quang province. Their petrographical composition includs light colored, small - to medium - grained size biotite granite and two - mica granite, and aplite. The crystallization temperature of granites calculated based on zircon saturation and chemical composition of granites is 787 to 740o C, coreponding to the forming - pressure and depth of <5 Kbar and 15 km, respectively. The rocks have high aluminum content with ASI> 1.1. The results of calculating the temperature by the method of zircon saturation and the main element for the forming temperature fluctuate in a wide range from about 787 to 740oC; The forming pressure is calculated based on the main element, fluctuating in the range <5 Kbar (corresponding to the forming depth of <15 km). Petrographic composition and geochemistry indicate that Chiêm Hóa granite is characterized by S-type granite, originated from the crust and formed at medium to shallow depth, similar to Phia Bioc granite.