1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. Museum of Geology, Jilin University, Changchun 130026, China;
3. Geology Institute of CNPC Greatwall Drilling Company, Panjin 124010, Liaoning, China

Taking the volcanic rocks from Guosong Formation in the Guosong Basin as research objects, accurate zircon U-Pb dating for the andesites of the typical section is undertaken to determine the formation age of the volcanic rocks. Most zircons of the selected samples are euhedral-subhedral in shape, and display distinct oscillatory zoning structures. The values of Th/U range in 0.48~2.77, implying a typical magmatic origin. Zircon U-Pb dating shows that the previous defined Mid-Late Jurassic Guosong Formation volcanic rocks actually formed in 130 Ma (weighted mean age is 130±2 Ma, MSWD=0.48) or 129 Ma(weighted mean age is 129±2 Ma, MSWD=0.14) and should be grouped into the Early Cretaceous. Based on the composition of the Mesozoic rock assemblage in Guosong Basin and combined with newly acquired zircon U-Pb dating and characteristics of fossil assemblages, the Mesozoic stratigraphic sequence in Guosong Basin has been redefined, and the stratigraphic correlation of the Cretaceous units in the Guosong Basin with adjacent areas has been investigated.