首页 | 本学科首页   官方微博 | 高级检索  
     检索      

河南东沟钼矿花岗斑岩成因: 岩石地球化学、锆石U-Pb年代学及Sr-Nd-Hf同位素制约
引用本文:戴宝章,蒋少涌,王孝磊.河南东沟钼矿花岗斑岩成因: 岩石地球化学、锆石U-Pb年代学及Sr-Nd-Hf同位素制约[J].岩石学报,2009,25(11):2889-2901.
作者姓名:戴宝章  蒋少涌  王孝磊
作者单位:南京大学地球科学系内生金属矿床成矿机制研究国家重点实验室,南京,210093
基金项目:科技部973计划课题 
摘    要:本研究对东沟超大型钼矿床的成矿母岩-东沟花岗斑岩开展了系统的年代学、岩石地球化学及Sr-Nd-Hf同位素分析工作.LA-ICP-MS锆石U-Pb定年结果表明,东沟花岗斑岩成岩年龄为114~117Ma,与已有的成矿年龄(116±2Ma,Re-Os法)一致,证实了东沟钼矿为一斑岩型矿床.详细的岩石地球化学分析显示东沟花岗斑岩岩体与区域上太山庙大型花岗岩基为同源演化关系,它们均为弱过铝质,具有富Si、富K、富Rb、Th、U等大离子亲石元素、富Nb、Ta、Zr、Hf等高场强元素,贫Fe、Mg、Ca,贫Sr、Ba,Ga/Al比值较高等地球化学特征,属铝质A型花岗岩,形成于伸展构造体制,东沟岩体是母岩浆经历了强烈结晶分异高度演化的产物;东沟岩体Nd同位素组成为0.51166~0.51182,ε_(Nd)(t))值在-17.3~-14.3之间,锆石的ε_(Hf)(t)值变化较大,由-3.4至-18.7,另有一颗年龄为1715Ma的捕获锆石的ε_(Hf)(t)值为-2.4,Nd、Hf模式年龄分别为1.5~1.8Ga与1.3~1.7Ga.我们认为东沟岩体的岩浆源区以古老地壳物质为主,但也有少量幔源组分参入,并且幔源物质的加入及很高的岩浆演化程度可能对东沟钼矿的成岩成矿过程具有重要作用.

关 键 词:东沟超大型斑岩钼矿  铝质A型花岗岩  锆石U-Ph定年  Sr-Nd-Hf同位素  伸展体制  幔源物质

Petrogenesis of the granitic porphyry related to the giant molybdenum deposit in Donggou, Henan province, China: Constraints from petrogeochemistry,zircon U-Pb chronology and Sr-Nd-Hf isotopes.
DAI BaoZhang,JIANG ShaoYong,WANG XiaoLei.Petrogenesis of the granitic porphyry related to the giant molybdenum deposit in Donggou, Henan province, China: Constraints from petrogeochemistry,zircon U-Pb chronology and Sr-Nd-Hf isotopes.[J].Acta Petrologica Sinica,2009,25(11):2889-2901.
Authors:DAI BaoZhang  JIANG ShaoYong  WANG XiaoLei
Abstract:In this study,we carried out a comprehensive research including zircon U-Pb dating,petrogeoehemistry and Sr-Nd-Hf isotope analysis on the granitic porphyry related to the giant molybdenum deposit in Donggou,Henan Province,China.LA-ICP-MS zircon U-Pb chronology indicated that the Donggou porphyry emplaced at 114~117Ma,identical with the time when the molybdenum deposit were formed(116±2Ma,Re-Os age).Both the Donggou porphyry and the large Taishanmiao batholith to its south are enriched in Si,K,LILEs such as Rb,Th and U,and HFSEs such as Nb,Ta,Zr and Hf,while depleted in Fe,Ms,Ca,Sr and Ba.They are weakly peraluminous and show high Ga/Al ratios,and thus can be classified as aluminous A-type granite.The primitive magma experienced very high extent of crystal fractionation and then emplaced to form the Donggou porphyry in an extension setting.The Nd isotopic compositions of the Donggou samples range from 0.51166 to 0.51182,with corresponding ε _(Nd)(t)values of-17.3 to -14.3.The ε_(Hf)(t)values also show a large range(-3.4 to-18.7)with a xenocryst yielding ε_(Hf)(t)value of-2.4 at 1715Ma.Based on above isotopic data,we argue that the magma sources of the Donggou porphyry were composed of mainly old crustal rocks,but may also involve some portions of mantle materials.We suggested that input of mantle-derived melt and highly evolved nature of the Donggou porphyry are important for the formation of the giant molybdenum deposit.
Keywords:Donggou giant porphyry-type molybdenum deposit  aluminous A-type granite  zircon U-Pb dating  Sr-Nd-Hf isotopes  extension setting  mantle materials
本文献已被 万方数据 等数据库收录!
点击此处可从《岩石学报》浏览原始摘要信息
点击此处可从《岩石学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号