ISOTOPIC U-PB ZIRCON AGE OF VOLCANIC ROCKS IN THE T LỆ DEPRESSION

Phạm Đức Lương1, Đặng Trần Huyn2, Nguyễn Đnh Hữu2,
Nguyễn Đức Phong2, Nguyễn Thị Bch Thủy3
,

1 Vietnam Union of Geological Sciences, No. 6 Pham Ngu Lao, Hanoi
2
Vietnam2Vietnam Institute of Geosciences and Mineral Resources, Km9, Nguyen Trai, Thanh Xuan, Hanoi

3General Department of Geology and Minerals of Vietnam, No. 6 Pham Ngu Lao, Hanoi
Corresponding author: thuynguyendcks@yahoo.com

Abstract: Based on U-Pb zircon (LA-ICP-MS) analysis zircon U-Pb ages of trachyrhyolite and rhyolite collected in the T Lệ Depression, it was determined that the ages range range mainly from 93 to 118 Ma, corresponding to the Early-Late Cretaceous. These results are consistent with almost all published ages. The rhyolite sample with the age of 256 Ma may have genetic relation with Permian felsic rocks in the Sng Đ intracontinental rift. This sample, perhaps, belongs to the basement of the T Lệ Depression. The T Lệ Depression is an independent structure and was filled mainly with alkaline-subalkaline felsic extrusive rocks, while mafic-ultramafic extrusive rocks are widespread in the Sng Đ intracontinental rift.

Keywords: U-Pb zircon, volcanic rocks, T Lệ Depression.

 


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