文章摘要
王波华,李利,倪培,王国光,陈辉,江来利,张怀东.安徽北淮阳地区金矿化相关火山岩的形成年代和源区特征:锆石U-Pb定年和Hf同位素的制约[J].矿产勘查,2017,8(3):348-357
安徽北淮阳地区金矿化相关火山岩的形成年代和源区特征:锆石U-Pb定年和Hf同位素的制约
Formation age and characteristics of magma sources of volcanics related to gold mineralization in the Beihuaiyang zone,Anhui: Constraints from zircon U-Pb dating and Hf isotopes
投稿时间：2016-12-02  
DOI：
中文关键词: 金矿化  新店河英安岩  LA-ICP-MS  锆石U-Pb定年  锆石Hf同位素  安徽
英文关键词: gold mineralization, Xindianhe dacite, LA-ICP-MS zircon dating, zircon Hf isotope, Anhui
基金项目:安徽省公益性地质(科技)项目(编号:2009-19)和国家重点研发计划(编号:2016YFC0600206)联合资助。
作者单位
王波华 安徽省地质矿产勘查局313地质队, 六安 237010 
李利 南京大学内生金属矿床成 矿机制研究国家重点实验室,地质流体研究所,地球科学与工程学院, 南京 210046 
倪培 南京大学内生金属矿床成 矿机制研究国家重点实验室,地质流体研究所,地球科学与工程学院, 南京 210046 
王国光 南京大学内生金属矿床成 矿机制研究国家重点实验室,地质流体研究所,地球科学与工程学院, 南京 210046 
陈辉 国土资源部矿产勘查技术指导中心,北京 100037 
江来利 安徽省地质调查院,合肥 230001 
张怀东 安徽省地质矿产勘查局313地质队, 六安 237010 
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中文摘要:
      安徽北淮阳地区发育中酸性陆相火山岩相关的金矿化,本次研究选取金矿化相关的新店河英安岩开展锆石LA-ICP-MS U-Pb年代学及LA-MC-ICP-MS Lu-Hf 同位素研究。结果显示锆石Th/U比值为1.21~2.57,明显高于Th/U比值小于0.1的变质成因的锆石,为典型岩浆成因锆石。英安岩年龄加权平均值为(130±2)Ma(n=13,MSWD=1.4)；结合锆石自形、发育岩浆环带等特点,该年龄是新店河英安岩的成岩年龄。锆石Hf同位素研究显示,新店河英安岩的εHf(t)在-31.6～-26.3之间,两阶段模式年龄变化范围为2.82～3.15 Ga,为中—新太古代的基底部分熔融而成。新店河英安岩有较好的金矿化潜力,因此北淮阳地区金矿化可能形成于早白垩世后碰撞伸展环境,是大别造山带构造垮塌导致的大规模岩浆作用的产物。结合前人资料,北淮阳地区矿化可以划分为两个阶段:早期火山热液型金矿化(130 Ma)和晚期斑岩型钼矿化(114 Ma)。
英文摘要:
      This paper presents LA-ICP-MS zircon dating and zircon Hf isotopic data of the Xindianhe dacite related to gold mineralization in the Beihuaiyang zone, Anhui Province. The Th/U ratios of zircons range from 1.21 to 2.57, which indicated that they are magmatic zircons in origin. The Xindianhe dacite has weighted mean age of (130±2) Ma (n=13, MSWD=1.4), which indicated it is the crystallization age of the Xindianhe dacite in consideration of euhedral texture and zonary structure of zircon mineral. The measurement of zircon Hf isotopes show that εHf(t) value ranges from -31.6 to -26.3 and corresponding two-stages ages are 2.82 to 3.15 Ga, which indicated that it was formed by the melting of the Meso-Archean to Neo-Archean basement. The gold mineralization in the Beihuaiyang region likely results from the large-scale magmatism related to the orogenic collapse which were formed in the post-collisional extensional setting in the post early Cretaceous period. In combination with previous data, two-stages of gold mineralization are identified, i.e., early stage epithermal gold mineralization (about 130 Ma age) and late stage porphyry Mo mineralization (about 114 Ma age). Therefore there is great prospecting potential for epithermal gold deposit in the Xindianhe region.
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