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| 河南大湖金钼矿床成矿物质来源的锶钕铅同位素约束 | |
| 引用本文： | 倪智勇,李诺,张辉,薛良伟.河南大湖金钼矿床成矿物质来源的锶钕铅同位素约束[J].岩石学报,2009,25(11):2823-2832. |
| 作者姓名： | 倪智勇 李诺 张辉 薛良伟 |
| 作者单位： | 1. 北京大学造山带与地壳演化重点实验室,北京,100871;中国科学院地球化学研究所地球深部物质与流体作用地球化学研究室,贵阳,550002 2. 北京大学造山带与地壳演化重点实验室,北京,100871 3. 中国科学院地球化学研究所地球深部物质与流体作用地球化学研究室,贵阳,550002 4. 河南省国土资源科学研究院,郑州,450053 |
| 基金项目： | 国家"973"计划项目，国家自然科学基金项目，中国科学院百人计划项目的资助 |
| 摘 要： | 河南灵宝大湖金钼矿床位于小秦岭金矿田北缘,属典型的断控脉状矿床.前人较好研究了矿床流体包裹体和成矿年代,但对成矿物质来源研究薄弱.本文对16件矿石硫化物及5件赋矿围岩样品进行了Sr-Nd-Pb同位素分析,金属硫化物I_(Sr)=0.70470～0.71312,平均0.70854;(~(143)Nd/~(144)Nd)_i=0.51143-0.51215,平均0.51162;(~(206)Pb/~(204)Pb)_i=17.033～17.285,(~(207)Pb/~(204)Pb)_i=15.358～15.438,(~(208)Pb/~(204)Pb)_i=37.307-37.582,平均值分别是17.162,15.405,37.440.5件太华超群样品I_(Sr)=0.70947～0.73201,平均0.72294;(~(143)Nd/~(144)Nd)_i=0.51076～0.51133,平均0.51107;(~(206)Pb/~(204)Pb)_i=17.127～18.392,(~(207P)b/~(204)Pb)_i=15.416～15.604,(~(208)Pb/~(204)Pb)_i=37.498～37.814,平均值分别是17.547,15.470,37.616.Sr-Nd-Pb同位素特征表明成矿物质来源具壳幔混合特征,初始成矿流体可能来源于亏损的残余洋壳,并通过成矿过程的水岩相互作用与太华超群混合;据此认为,在218Ma年左右,秦岭地区的陆陆碰撞造山作用并没有结束,而仍在进行之中. |
| 关 键 词： | Sr-Nb-Pb同位素 成矿物质来源 大湖金钼矿床 小秦岭金矿田 A型俯冲 |
2009.Pb-Sr-Nd isotope constraints on the source of ore-forming elements of the Dahu Au-Mo deposit, Henan province |
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| NI ZhiYong,LI Nuo,ZHANG Hui,XUE LiangWei.2009.Pb-Sr-Nd isotope constraints on the source of ore-forming elements of the Dahu Au-Mo deposit, Henan province[J].Acta Petrologica Sinica,2009,25(11):2823-2832. | |
| Authors: | NI ZhiYong LI Nuo ZHANG Hui XUE LiangWei |
| Abstract: | The Dahu Au-Mo deposit,Lingbao County,Henan Province is a typical fault-controlled lode deposit occurring in the northern Xiaoqinling gold field.The fluid inclusions and mineralization age have been well documented,but the ore-forming metal source has not been discussed in previous studies.This paper reports analytical results of Sr-Nd-Pb isotope systematics for 16 sulfide samples(7 pyrite,4 molybdenite,3 galena and 2 chalcopyrite)and 5 ore-hosting rocks of Taihua Supergroup gneisses.The sulfides yield I_(Sr) of 0.70470～0.71312,with a mean value of 0.70854,(~(143) Nd/~(144) Nd)_i of 0.51143～0.51215(average 0.51162),and (~(206)Pb/~(204)Pb)_i,(~(207) Pb/~(204)Pb)_i and(~(208) pb/~(204)pb)_i of 17.033～17.285,15.358～15.438 and 37.307～37.582,with a mean value of 17.162,15.405 and 37.440,respectively.Whilst the gneisses of Taihua Supergroup yield I_(Sr) of 0.70947～0.73201 with an average of 0.72294,(~(143) Nd/144Nd)_i of 0.51076～0.51133 with an average of 0.51107,(~(206) Pb/~(204) Pb)_i of 17.127～18.392,averaging 17.547,(~(207)pb/~(204)pb)_i of 15.416～15.604,averaging 15.470 and(~(208)Pb/~(204)Pb)_i of 37.498～37.814,averaging 37.616,respectively.The Sr-Nd-Pb isotope systematics shows a source of mixing crust and mantle.Therefore,it is concluded that the oreforming materials or fluids originated initially from a residual depleted ocean crust,which had subducted and accumulated beneath the interested area,and then mixed the Taihua Supergroup during fluid-rock interaction;and that time the continental collision between Yangtze and North China were not ended yet,instead,it just widely began at about 218 Ma. |
| Keywords: | Sr-Nd-Pb isotope systematics Ore-forming element source Dahu Au-Mo deposit Xiaoqinling gold field A-typesubduction |
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