吉林百草沟金矿闪长玢岩锆石U_Pb年代学、地球化学及其地质意义

发布时间：2018-01-16 16:34

  本文关键词：吉林百草沟金矿闪长玢岩锆石U_Pb年代学、地球化学及其地质意义　出处：《矿床地质》2016年05期 　论文类型：期刊论文

  更多相关文章： 地球化学 锆石U_Pb年龄 百草沟金矿 闪长玢岩 活动大陆边缘

【摘要】：文章对延边地区百草沟金矿床与成矿有关的闪长玢岩脉进行了锆石LA_ICP_MS U_Pb年代学和地球化学研究。闪长玢岩中的锆石U_Pb定年结果显示,闪长玢岩形成时代为早白垩世((128±3)Ma,MSWD=0.29)。岩石元素地球化学研究表明岩石属于高钾钙碱性系列,明显富集大离子亲石元素(如K、Ba、Rb)、LREE和强不相容元素(如Th、U),相对亏损高场强元素(如Ta、Nb、Ti、P),Mg#值为42~54,其地球化学特征与活动大陆边缘背景下形成的火成岩相似。岩石中w(Cr)为20.0×10-6~33.4×10-6,Nb/Ta比值为9.7~16.5,La/Nb比值为2.54~3.67,Th/La比值为0.19~0.43,Rb/Sr值比为0.10~0.33,闪长玢岩岩浆是由地壳物质和地幔物质混合形成的。结合野外地质特征及年代学,认为与矿床近同时形成的闪长玢岩,其形成的构造背景应为古太平洋板块斜向亚洲大陆俯冲的活动大陆边缘。
[Abstract]:Zircon LA_ICP_MS of diorite porphyrite veins related to mineralization of Baicaogou gold deposit in Yanbian area has been carried out in this paper. U-Pb geochronology and geochemistry. Zircon dating of zircon from diorite porphyrite shows. The diorite porphyrite was formed at an early Cretaceous age of 128 卤3 MaMSWDU 0.290.The geochemistry of the rocks indicates that the rocks belong to the calc-alkaline series of high potassium. The large ion lithophile elements (such as K _ (+) Ba _ (B) Rb ~ (+)) LREE and strongly incompatible elements (such as Thu U ~ (2 +), relatively depleted high field strength elements (such as Tahe NbTiPe) are obviously enriched. The Mg# value is 42 #number0#, and its geochemical characteristics are similar to those of igneous rocks formed in the active continental margin. The ratio of Nb/Ta to La / NB is 9.7and 16.5nb is 2.54 / 3.67U / L / La ratio is 0.19nb / 0.43. The Rb/Sr ratio is 0.10 ~ 0.33 and the diorite porphyrite magma is formed from the mixture of crustal and mantle materials. Combined with the field geological characteristics and geochronology, it is considered that the diorite porphyrite formed near the same time as the deposit. The tectonic setting is the active continental margin in which the paleo-Pacific plate dips to the Asian continent.
【作者单位】： 中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室;北京大学地球与空间科学学院;吉林大学地球科学学院;
【基金】：吉黑东部区域成矿规律综合研究项目(编号:1212011085485) 中央高校基本科研业务费专项资金(编号:310827161011)联合资助
【分类号】：P597.3;P618.51
【正文快照】： combination with their Mg#values(42~54),it is suggested that the features of the rocks are similar to the charac-teristics of active continental margin magma.Based on the data Cr=(20.0~33.4)×10-6,Nb/Ta=9.7~16.5,La/Nb=2.54~3.67,Th/La=0.19~0.43,and Rb/Sr=，

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