Abstract
The crystallization age of the two mica granite in the Sầm Sơn Block is determined by U-Pb zircon LA-ICP-MS method. Most of the analytical results 206Pb age / 238U ranged from 225-235 Ma., average of 227 ± 4 Ma. This dating results indicated the impact of the Indosinian thermo-tectonic event in the study area. The older dating values centered at ~400Ma and ~750 Ma. suggested that the continental crust of the study area the Middle Paleozoic and Neoproterozoic compositions. εHf(t) show negative values, which varies between -9 ~ -11, Hf model ages (Tdm2) concentrated around ~1.9 Ga. It is proposed that the granite in Sầm Sơn has been formed by partial melting of the Paleoproterozoic crustal materials.