投稿时间：2015-01-10
修订日期：2016-06-30
网络发布日期：2016-10-29
中文摘要: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:LA-ICP-MS zircon U-Pb dating and geochemical data of the diorite-porphyrite rocks, which are related to ore formation, from the Baicaogou gold deposit of Yanbian region were obtained to restrain their formation time and the regional tectonic background. The dating results indicate that these rocks were formed in the Early Cretaceous ((128±3) Ma,MSWD=0.29). The element compositions of these rocks are transitional from shoshonite series to potassium-high calc-alkaline series, characterized by enrichment of LILE(such as K, Ba and Rb),LREE and more mobile incompatible elements (such as Th, U), and relatively depleted in HFSE(such as Ta, Nb, Ti and P). In combination with their Mg# values (42~54), it is suggested that the features of the rocks are similar to the characteristics 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=0.10~0.33, it can be concluded that the magma was derived from mixture of the crust and the mantle. Together with the research on geological features and geochronology, the authors mainly studied diorite-porphyrite rocks similar to ore in formation time, and the formation background of diorite-porphyrite rocks was that of active continental margin closely related to the subduction of paleo-Pacific plate towards the Eurasia continent.
keywords:geochemistry zircon U-Pb chronology Baicaogou gold deposit diorite-porphyrite rocks active continental margin
文章编号：
中图分类号：P618.31
文献标志码：
基金项目:本文得到吉黑东部区域成矿规律综合研究项目（编号：1212011085485）和中央高校基本科研业务费专项资金（编号：310827161011）联合资助
引用文本：
李睿华,孙丰月,刘金龙,李良,赵拓飞,闫佳铭.2016.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[J].矿床地质,35(5):1023~1034LI RuiHua,SUN FengYue,LIU JinLong,LI Liang,ZHAO TuoFei,YAN JiaMing.2016.Zircon U-Pb chronology and geochemistry of diorite-porphyrite from Baicaogou gold deposit in Yanbian region, Jilin Province, and its geological significance[J].Mineral Deposits35(5):1023~1034
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