西准噶尔萨吾尔地区黑山头金矿点二长岩锆石U-Pb年代学和地球化学特征:对成矿前景的指示

发布时间：2018-07-26 16:26

【摘要】：黑山头金矿点是西准噶尔萨吾尔地区最新发现的金矿化点,通过对该金矿点赋矿岩石的LA-ICP-MS锆石U-Pb年龄以及地球化学特征的研究,探讨其构造背景及成因信息。黑山头金矿点赋矿岩石主要为二长岩,矿化区内发育钾长石化、硅化、青磐岩化、碳酸盐化等蚀变。二长岩LA-ICP-MS锆石U-Pb年龄为351.1±3.2 Ma,表明其形成于早石炭世早期。主量元素特征显示其属于钙碱性准铝质岩石,相对洋中脊玄武岩富集Sr、Ba、Th等大离子亲石元素,亏损Nb、Ta、Ti等高场强元素。二长岩为典型的I型花岗岩,区域地质及地球化学特征指示其形成于岛弧环境。矿区内二长岩具有高Sr、Na_2O和Al_2O_3,低Y和HREE等特征,与埃达克岩地球化学特征一致。样品具有较高的ε_(Nd)(t)和较低的(~(87_Sr/~(86)Sr)t,结合它们形成于晚古生代岛弧环境,暗示这些埃达克岩可能由俯冲洋壳熔融形成;而萨吾尔地区早石炭世晚期(340 Ma)中酸性侵入岩可能为玄武质下地壳熔融的产物。本次新发现的埃达克岩为该区进一步寻找斑岩矿床提供了有用线索,并且矿床围岩蚀变特征、矿化特征与斑岩矿床相似,暗示黑山头矿点具有良好的成矿条件和找矿潜力。
[Abstract]:The heyshetou gold spot is the most newly discovered gold mineralization point in the Sawu area of Western Junggar. Through the study of the LA-ICP-MS zircon U-Pb age and geochemical characteristics of the ore bearing rocks in the gold deposit, the tectonic background and genetic information are discussed. The ore bearing rocks of the heyshead gold deposit are mainly two long rocks, and the potash long fossilization, silicification and green are developed in the mineralized area. The LA-ICP-MS zircon U-Pb age of the two long rock is 351.1 + 3.2 Ma, indicating that it was formed in the early Early Carboniferous. The main element characteristics showed that it belonged to the calcium alkaline paralic rock, and the middle ridge basalt was rich in Sr, Ba, Th and other large ionic stone elements, and lost the high field strong elements such as Nb, Ta, Ti and so on. Two long rock was a typical I type. Granite, regional geological and geochemical characteristics indicate that it is formed in the island arc environment. The two long rocks in the mining area have the characteristics of high Sr, Na_2O and Al_2O_3, low Y and HREE, which are consistent with the geochemical characteristics of the epic rocks. The samples have high epsilon (Nd) (t) and lower (~ (87_Sr/~ (86) Sr) t, which are formed in the late Paleozoic island arc environment, implying that Some of the etydic rocks may be fused by subducted oceanic crust; and the acid intrusive rocks in the late Early Carboniferous (340 Ma) in the soual region may be the product of the melting of the basaltic lower crust. The newly discovered etacites provide useful clues for further finding the porphyry deposits in the area, and the alteration of the surrounding rocks of the deposit, mineralization characteristics and porphyry deposits. Similar beds suggest that the hehshan ore deposit has good metallogenic conditions and prospecting potential.
【作者单位】：新疆有色地质勘查局706队;
【基金】：“十二五”国家科技支撑计划项目(2011BAB06B01)资助
【分类号】：P597.3;P618.51

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