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

Phạm Đức Lương¹, Đặng Trần Huyên², Nguyễn Đình Hữu²,
Nguyễn Đức Phong², Nguyễn Thị Bích Thủy³,

¹ Vietnam Union of Geological Sciences, No. 6 Pham Ngu Lao, Hanoi
²Vietnam²Vietnam 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 Tú 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 Sông Đà intracontinental rift. This sample, perhaps, belongs to the basement of the Tú Lệ Depression. The Tú 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 Sông Đà intracontinental rift.

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

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