Abstract: Tuohe volcanic basin is located in the Keshiketeng, Inner Mongolia, southern segment of the Great Xing'an Range. It belongs
to the Liaoyuan block，which is located between Xar Moron River-Changchun suture zone and Kangbao-Weichang-Chifeng-Kaiyuan
fault zone. The felsic volcanic rocks unconformably overlie the lower Permian Elitu Formation and are overlain by basalts in the basin.
The zircon SHRIMP U-Pb ages of rhyolites in the base indicate a 206Pb / 238U age of 158.5±1.3 Ma, suggesting that it is the product of
the early stage of Late Jurassic magmatism, belonging to the Xinmin Formation. The Tuohe rhyolites show high content of SiO2 A/CNK <
1.1， the content of standard mineral corundum is less than 1% , high ΣREE and the LREE are enriched with an negative Eu
abnormaly, (87Sr/86Sr)i=0.709244~0.713168, εNd(t) =-8.76~-8.42, TDM2=1656~1629 Ma, (206Pb/204Pb)i=17.271~17.326, (207Pb/204Pb) i =
15.401~15.413, (208Pb/204Pb) i =37.614~37.696, δ18OV-SMOW=4.1‰~4.5‰. The main elements, trace elements and Sr-Nd-Pb-O isotopes
geochemical characteristics of rhyolite in Tuohe basin are basically the same as those of rhyolite and rhyolite porphyry in Hongshanzi
Basin and Zhirui Basin, implying that the material sources of these basins are the same. This paper supports the notion that the material
sources are related to both the crust, especially the lower crust, and the mantle, especially the EMI-type mantle. On the diagram of (Yb
+ Ta)-Rb vs. Y-Nb, the rhyolite in the Tuohe Basin shows that it is an intra-plate tectonic setting. Comparing with the rock
assemblages, geological ages, isotopic composition, and uranium mineralization characteristics of the Hongshanzi basin, the
mineralization conditions in Tuohe basin are better. This study suggests that future exploration of uranium deposits in the basin should
be conducted with the guide from the model of Hongshanzi uranium-molybdenum deposits.

Key words: rhyolite, geochemistr, Sr-Nd-Pb-O isotopes, tectonic setting, Xinmin Formation, Tuohe