Abstract:Due to the lack of high-precision chronological constraints, the age and stratigraphic attribution of the "Dibucuo Formation" in Nixiong area are controversial. In this paper, the weighted average age of ~120 Ma was obtained through zircon U-Pb dating from the andesite intercalayion in the "Dibucuo Formation". These data, in combination with the existing research data on detrital zircons of the "Dibucuo Formation" in the studied area, led us to conclude that the so-called "Dibucuo Formation" was formed in Early Cretaceous (130~120 Ma), which is consistent with the formation age of the colcanic-sedimentary strata of the Zenong Group in this region. It is thus suggested to tentatively classify the "Dibucuo Formation" into the Zenong Group. According to the whole-rock geochemistry of andesite samples and the in-situ zircon Hf isotopic composition, it is believed that the andesite was derived from of the mixture of crust-derived felsic magma and mantle-derived basaltic magma, and formed in the subduction tectonic environment. By further summarizing and analyzing the spatio-temporal transformation of Meso-Cenozoic magmatism in the Lhasa Terrane, it is revealed that the dynamic mechanism of the formation of this set of andesites is mainly related to the northward subduction of the Neo-Tethys Oceanic slab.