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对滇西北金沙江带羊拉矿区的基性岩进行了系统的主量元素和微量元素研究,同时对比白茫雪山-拱卡路线上与蛇绿岩共生的玄武熔岩的地球化学性质,探讨羊拉矿区基性岩形成的地质构造背景。研究表明,矿区下石炭统贝吾组玄武岩与白茫雪山-拱卡玄武岩地球化学性质相似,具洋脊之特征,低K,Ti,轻重稀土元素分馏不明显,微量元素特征指示二者可能来自于较富集的源区,均为金沙江洋盆扩张的产物,属于缝合带的组成部分。矿区泥盆系地层内的辉绿岩脉斜交侵入围岩,晚于火山岩和洋盆沉积物的形成,辉绿岩脉稀土元素标准化曲线右倾,强不相容元素富集,Ta、Nb亏损,具大陆边缘岛弧性质,微量元素特征与大洋玄武岩和洋内岛弧玄武岩亦存在一定差异,推测辉绿岩脉可能形成于三叠纪金沙江带陆缘岛弧岩浆活动阶段,对于有的学者确定该区为洋内岛弧构造环境的认识在本次工作中没有得到验证。
The basic elements and trace elements of the basic rocks in the Yilala mining area of Jinsha River in northwestern Yunnan were systematically studied. Meanwhile, the geochemical characteristics of basaltic lavas symbiotic with ophiolites on the Baimoushan-Arca route were compared, Geology and tectonic setting of basic rocks formed in the ore drawing area. The study shows that the Lower Carboniferous Basalts in the Lower Carboniferous of the mining area have similar geochemical characteristics to Ba Mang snow-arched basalt basalt, and are characterized by oceanic ridges. There is no obvious fractionation of low K, Ti and heavy and light rare earth elements, and the trace element characteristics indicate that both may come from In the richer source areas, they are all the products of the Jinsha River basin expansion and are part of the suture zone. The diabase dykes in the Devonian strata of the mining area intruded into the surrounding rocks obliquely. Later than the formation of volcanic and oceanic sediments, the normalization curves of rare earth elements in the diabase dikes are rich in strong incompatible elements, depleted in Ta and Nb, With continental marginal island arc, trace element characteristics and oceanic basalt and intra-oceanic island basalts there are also some differences, suggesting that diabase dikes may form in the Triassic Jinshajiang continental marginal island magmatic activity phase, for some scholars to determine The understanding of this area for the intracontinental island arc tectonic environment has not been validated in this work.