1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. The 3rd Oil Production Plant of Daqing Oilfield, Daqing 163318, Heilongjiang, China

Zircon LA-ICP-MS U-Pb geochronology of Huoluotai granite in the studied area shows that the weighted mean age of the rock is 148.12±0.85 Ma, which is of Early Cretaceous. The composition of elementary geochemistry indicates that the granite has high content of SiO₂(66.53%-68.92%), K₂O+Na₂O (8.80%-9.02%) and Al₂O₃ (15.16%-16.09%), but low MgO (0.72%-0.91%) and Mg^# (23.59-29.51). The aluminum saturation index (A/CNK) is 0.87-0.95, with high Sr content of (466.00-688.00)×10^-6 and low Y of (4.65-6.22)×10^-6. It is indicated that the granite is a set of adakitic rocks with the characteristics of high-K calc-alkaline series. Fraction of light and heavy rare earth elements is obvious, with (La/Yb)_N=58.22-117.91, and anomaly of Eu is feeble (δEu=0.83-0.99). The samples are also enriched in light rare earth elements and large ion elements (Rb, K), depleted in heavy earth elements and high field strength elements (Nb,Ti, P, Zr). Combined with the characteristics of regional tectonic evolution, it is suggested that the fine granite originated from the partial melting of the thickened lower crust, which should be related to the collision compression orogeny after the closure of the Mongolia-Okhotsk Ocean.