Abstract:Zhifanggou tectonic slice is located in Mianlue tectonic zone, Lueyang area. On the basis of detailed petrological and geochemical studies, we identify that the main rock types in the Zhifanggou tectonic slice are a combination of tholeiite (type Ⅰ) and calc-alkaline volcanic rocks(type Ⅱ). Type Ⅰ volcanic rocks possess the features of normal mid-ocean ridge basalt on the whole, such as left-leaning REE patterns, Na-rich, and P-poor, indicating that they were generated in mid-ocean ridge setting. Type Ⅱ volcanic rocks have higher SiO2(49.02％~61.86％) and K2O(0.32％~1.55％) concentrations than type Ⅰ, negative anomaly of Nb, Ta, P, Ti, suggesting generation in a continental marginal arc setting. The zircon Lu-Hf isotopic composition show that the zircon εHf(t) of type Ⅱ volcanic rocks ranges from -8.01 to +0.77 , suggesting that these melts were derived from old continental crust material. The LA-ICP-MS zircon U-Pb age determined using laser ablation–inductively coupled plasma–mass spectrometry from Type Ⅱ volcanic rocks is 854±3Ma(MSWD=0.12, n=30) and 844±4Ma (MSWD=0.03, n=15), indicating the crystallized age of the volcanic rocks from Zhifanggou tectonic slice in Middle Neoproterozoic. The volcanic rocks from Zhifanggou tectonic slice are considered as the product of subduction of Neoproterozoic Mianlue Ocean, and the subduction did not quit until about ~800Ma. This process was likely to be response to the amalgamation of Rodinia supercontinent.