对曙光村角闪辉长岩主量、稀土和微量元素以及锆石LA-ICP-MS U-Pb进行测年分析.研究结果表明:SiO2平均质量分数为41.38％,具有明显的贫硅特点,明显贫碱,富Al,低K,Ti和P,镁值Mg#平均为40.99,低于原生岩浆范围(68～75),表明岩石经历了一定程度的分异演化;稀土模式曲线向右缓倾,轻重稀土分馏程度低,δ(Eu)弱正异常,暗示存在斜长石较弱的堆晶作用；总体上大离子亲石元素(LILE)Rb,Sr和K富集；高场强元素(HFSE)Nb和Zr中等亏损;锆石w(Th)/w(U)为0.66～1.48,且大多具有清晰的牛长振荡环带,表明为岩浆锆石；测年结果为(215±2.0) Ma,说明曙光村角闪辉长岩为晚三叠世岩浆活动的产物;形成于太平洋板块俯冲背景下佳木斯地块与松嫩地块碰撞后的伸展构造环境,地幔基性岩浆通过底侵作用,在上升过程中 与地壳物质发生混染.%The main element, rare earth element (REE) and trace element in bojite in Shuguang village and the dating method by zircon LA-ICP-MS U-Pb were analyzed. The results show that in bojite, the average mass fraction of SiCb is 41.38%, with obvious characteristics of depleted silicon. And alkali is poor but Al is rich. And K, Ti and P are lower. The average value of Mg# is 40.99, which is lower than primary magma range (68-75). This shows that the rock has experienced a certain degree of differentiation and evolution. It suggests the presence of weak cumulate effect of Plagioclase because the rare earth mode curve is gently inclined to right, and the degree of fractionation of heavy and light REE is low, and δ(Eu) is positive anomaly weakly. On the whole aspects, the large ion lithophile elements (LILE) including Rb, Sr and K in enrichment and the high strength elements (HFSE) including Nb and Zr in medium loss. The ratio of zircon w(Th)/w(U) is 0.66-1.48. And many of them have a clear growth oscillatory zoning, which indicates that they are magmatic zircon. By the dating result of (215±2.0) Ma, we speculat that the bojite in Shuguang village is the product of magma activity in Late Triassic, and is formed in the extensional tectonic environment after the collision of Jia Musi plots and Songnen mass if with the background of the subduction of the Pacific plate. Through the underplating, the mafic magma from the mantle showed contamination with crustal material in the rising process.
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