赣东北蛇绿岩和张村岩群的锆石SHRIMP U-Pb年龄及对江南造山带构造演化的讨论
发布时间：2018-10-29 21:41
【摘要】：本文对赣东北樟树墩蛇绿混杂岩中基性—超基性岩的地球化学分析表明,其中辉长岩具有MORB的地球化学特征,蛇纹岩强烈亏损各微量元素。辉长岩的锆石SHRIMP O同位素分析结果给出了非常均一的O同位素组成(5.12‰±0.62‰,2σ),与地幔锆石的O同位素组成(5.3‰±0.3‰)接近。这些地球化学特征和其形成于大洋环境吻合。锆石SHRIMP U-Pb定年给出了辉长岩的形成年龄为1009±5 Ma(MSWD=1.15)。在作为赣东北蛇绿岩的围岩张村岩群中,选取凝灰岩样品进行的锆石SHRIMP U-Pb定年给出了833±10 Ma(MSWD=1.5)的形成年龄,表明蛇绿岩就位时代晚于833 Ma。结合前人的研究,本文指出赣东北蛇绿岩形成于中元古代末—新元古代初的大洋中脊环境,不同于皖南伏川蛇绿岩所代表的弧后小洋盆环境。这些新资料为华南区域大地构造演化研究提供了新的约束。
[Abstract]:Geochemical analysis of basic-ultrabasic rocks in the Zhangshudun ophiolite in northeastern Jiangxi shows that the gabbro has the geochemical characteristics of MORB and the ophiolite is strongly depleted of trace elements. The results of zircon SHRIMP O isotope analysis of gabbro show that there is a very uniform O isotope composition (5.12 鈥，
本文编号：2298910
[Abstract]:Geochemical analysis of basic-ultrabasic rocks in the Zhangshudun ophiolite in northeastern Jiangxi shows that the gabbro has the geochemical characteristics of MORB and the ophiolite is strongly depleted of trace elements. The results of zircon SHRIMP O isotope analysis of gabbro show that there is a very uniform O isotope composition (5.12 鈥，
本文编号：2298910
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