College of Earth Science, Jilin University, Changchun 130061, China

The granite of Huangtudaban in Suolun area is mainly composed of syenogranite, monzonitic granite and grangite-porphyry. LA-ICP-MS zircon U-Pb isotopic dating yields age of 129.9±2.3 and 125.9±3.7 Ma, indicating that they were formed in the Early Cretaceous. Geochemical studies show that the granites are characterized by rich silicon and alkalis, poor calcium and magnesium. Hence the granites belong to high-potassium calc-alkaline I-type rocks. he granites are enriched in K, Rb and LREE, and depleted in Nb, Ta, P, Ti, Ba and Sr, with strong negative Eu anomalies (��Eu=0.18~0.60). All above show that the granites were in accord with the characteristics of crust source magma. The zircons in the granites show high values of ��_Hf(t) (5.80~10.70) with two-stage Hf model ages of 502~804 Ma,suggesting that they are derived from the newly formed crust which is separated from Paleozoic-Neoproterozoic depleted mantle. The granites formed in non orogenic intraplate environment and may be closely related to the lithosphere extension after the closure of Mongol-Okhotsk Ocean.