Abstract:The LA-MC-ICP-MS U-Pb dating of the zircons from the two granites in Hugang area, the southwestern Fujian, are carried out.The results show that the n( 206Pb)/n(238U) ages of the zircons from the Zengkeng fine grain monzonitic granite change from 145.4±18.2 Ma to 151.4±7.9 Ma,and the weighted average U-Pb age is 147.98±0.86Ma ( 95% conf.,MSWD=0.62). The n( 206Pb)/n(238U) ages of the zircons from Guanyang medium—fine biotite monzonitic granite change from 141.2±4.1Ma to 145.5±1.9Ma,and the weighted average U-Pb age is 143.0±1.1 Ma (95% conf.,MSWD=0.41). Moreover,the content of trace elements indicate that two plutons were formed in the collision—extrusion tectonic environment and were of strong magmatic differentiation and high magma acidity, n(Al2O3)>\[n(CaO)+n(Na2O)+n(k2O)\], the rates of Rb/Sr and Rb/Nb are higher,but the contents of Ni,Cr are lower and REE patterns are the rightly oblique,which also suggest that the two plutons derive from continental crust and belong to aluminum supersaturation S-type granites.The Zengkeng and Guangyang granites are formed in the Late Jurassic( mid—late Stage of Yanshanian)and provided main material foundation for formation of iron, manganese and copper deposit.