Located to the north of the Zhenghe County,Fujian Province,the Dayaokeng Gold Deposit is one of the most important deposits in operation in Northewest Fujian.Based on the relationship between the dikes and gold mineralization in the deposit,these dikes can be pided into three types:pre-mineralization,syn-mineralization and post-mineralization.The pre-mineralization dikes are mostly relatively alkaline intermediate-acid ones,while the syn-mineralization dikes are acid ones and the post-mineralization dikes are intermediate to basic ones.Based on the U-Pb dating results for zircons in the pre-mineralization,syn-mineralization and post-mineralization dikes,it is concluded that the mineralization age of the Dayaokeng Gold Deposit is in the range of （107.7±7.0）-（119.3±2.5）Ma,with the major phase mineralization age greater than (112.4±1.9)Ma.Based on the U-Pb dating of the inherited zircons,the probable existence of the ancient Archean crust deep in the Northwest Fujian is suggested.