选取福建虎岗地区灌洋和增坑二个岩体进行LA-MC-ICP-MS锆石U-Pb测年.增坑细粒二长花岗岩岩体单颗粒锆石U-Pb年龄为145.4±18.2～151.4±7.9 Ma,加权平均值为147.98±0.86 Ma(可信度95%,MSWD=0.62).灌洋中细粒黑云母二长花岗岩岩体单颗粒锆石年龄为141.2±4.1 ～ 145.5±1.9Ma,加权平均值为143.0±1.1Ma(可信度95%,MSWD=0.41).二岩体形成于挤压碰撞的构造环境,微量元素含量表明,岩浆分异作用较强,酸性程度较高,n(A12O3) ＞n(CaO) +n(Na2O) +n(K2O),且有较高的Rb/Sr和Rb/Nb比值,低含量的Ni、Cr含量和右倾型的稀土元素模式,表明岩体岩浆起源于大陆地壳中沉积的源岩,属于铝过饱和S型花岗岩.增坑和灌洋岩体形成年代都为晚侏罗世(燕山中晚期),且为铁铜多金属矿成矿提供了物质基础.%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. IMa 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 ( Al2 O3) > [ n ( CaO) + n ( Na2 O) + n (k2 O ],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.
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