Abstract:

The northwest region of Vietnam is a combination of the sub-continents of Indochina, China - Vietnam, Sibumasu. This is a large area with long evolutionary and complex history, were recorded many geological, magmatic, tectonic events and associated with the valuable minerals. In the framework of this article, the age of light granites (leucogranites), its vascular distributions and small coverage, they penetrated the rocks of Ye Yen Sun complex (Permian-Triassic age). On the structural framework of Phan Si Pan belt, leucogranites distribute in Thac Bac area and other locations, previously, these fomations were classified as the rocks of Ye Yen Sun complex. Zircons from the leucogranite Thac Bac Sa Pa area, Lao Cai province (V0847-2) have the LA-ICP-MS U-Pb analyses clustered at 31.02 ± 0.66 Ma. The value of 31.02 ± 0.66 Ma dates protolith age for leucogranite Thac Bac. This result is consistent with the new results were recently published by other authors on U-Pb zircon age of Phan Si Pan belt, a mixed record magmatic tectonic activity in the Paleogene period. It is proposed that the leucogranite Thac Bac, Sa Pa in the northwestern Vietnam were related to the stage of the India -Asia collision in during the Paleogene