中文摘要：

为探讨青海都兰县沟里地区基性脉岩的成岩时代与构造环境，理解早古生代东昆仑地区的地质演化历史，对沟里地区发育的色德日辉绿岩进行了系统的岩石学、岩石地球化学和锆石U—Pb年代学研究。岩石学观察显示，色德日辉绿岩蚀变强烈，但仍保留明显的辉绿结构。岩石地球化学分析表明，辉绿岩的SiO2含量（45．70％-46．70％）与基性岩相当，属亚碱性玄武岩系列；全岩的CaO含量较高（19．64％-21．50％），与碳酸盐化、云母化等蚀变特征吻合；全岩稀土总量较低（64．53×10^-6-182．99×10^-6），具有轻稀土元素富集特征，其δEu为0．80-0．96、δCe为0．84—0．92，均呈负异常；富集大离子亲石元素（Rb、Th和U），而亏损高场强元素（Nb、Ta、Ti和Y）。全岩地球化学特征呈现岛弧玄武岩特征。LA—ICP—MS锆石U—Pb年龄为417．4±3．2Ma，形成于晚志留世。研究表明，色德日辉绿岩是俯冲板片的消减作用引发地幔物质产生部分熔融的产物，其形成与晚志留世东昆仑地区古特提斯洋壳俯冲消减作用有关。

英文摘要：

In order to explore the age and tectonic setting of the Gouli mafic dykes in eastern Kunlun, and further under- stand the early Paleozoic geological evolution of the Gouli area, the petrology, geochronology and geochemistry of the Sed- eri diabase has been performed in this paper. The petrographical characteristics show that the Sederi diabase has experi- enced strong alteration, but remains diabase texture. The rocks have SiO2 contents of 45.70% - 46.70% and belong to sub-alkaline basalt series. They have high CaO contents of 19.64% -21.50%, consistent with the alteration characteristics of carbonatization and micacization. The diabase is characterized by low total REE（ ZREE = 64.53×10^-6-182.99×10^-6） , enrichment in LREE and negative Eu（0.80-0.96）and Ce （0.84-0.92）anomalies. Meanwhile, the rocks are enriched in LILE（ Rb, Th and U）and depleted in HFSE （Nb, Ta, Ti and Y）. Therefore, the geochemistry indicates an are origin. LA-ICP-MS zircon U-Pb age is 417.4-3.2 Ma, indicative of the product of Early Paleozoie magmatie activity. In conclusion, the Sederi diabase is a product of partly melted mantle material caused by Paleo-Tethys oceanic crust subduction during late Silurian in Eastern Kunlun.