| 甘肃岷县寨上金矿成矿年代及矿床成因探讨SCIEI北大核心CSCD |
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| 引用本文： | 王宇昊,杜志伟,焦学尧,马锦龙.甘肃岷县寨上金矿成矿年代及矿床成因探讨SCIEI北大核心CSCD[J].岩石学报,2022,38(4):1237-1252. |
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| 作者姓名： | 王宇昊 杜志伟 焦学尧 马锦龙 |
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| 作者单位： | 兰州大学地质科学与矿产资源学院, 兰州 730000;甘肃省地质调查院, 兰州 730000 |
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| 基金项目： | 本文受国家自然科学基金项目（41173014）资助. |
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| 摘 要： | 寨上金矿位于西秦岭大规模卡林-类卡林型金矿床集中地之中,是近二十年来探获的又一超大型金矿。通过对寨上金矿的6件矿石样品中的载金矿物黄铁矿进行Rb、Sr、Re、Os同位素分析,获得Rb-Sr、Re-Os等时线年龄分别为273±10Ma、273Ma±22Ma。该数据大于前人所获的二期成矿阶段年龄,在西秦岭已探明的金矿床中尚无报道,反映了寨上金矿更早一期的成矿年龄为273Ma,这也为该区域寻找金矿床拓宽了时间轴。Sr、Os、S同位素及稀土和微量元素研究表明,寨上金矿成矿物质为深源与壳源物质的混合。二叠纪时位于岷礼前陆盆地的吴家山隆起经历了强烈的隆升延展作用,岩浆热液沿断裂通道上升到有较高Au背景值盆地中的褶皱带,使地层中的Au活化富集,在构造有利部位卸载成矿,形成早期寨上金矿床,后期钨矿化及金矿化叠加在早期金矿床之上。寨上金矿第一期金成矿的年龄在时空上与阿尼玛卿洋盆闭合、共和坳拉谷俯冲碰撞、江里沟及中川喜马拉雅型岩体的侵入时间基本吻合,符合“地壳加厚有利于形成金矿床及喜马拉雅型花岗岩与金矿关系密切”的结论,对在该区域寻找同时代金矿床具有一定的指示意义。
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| 关 键 词： | 寨上金矿 成矿年代 成矿期次 矿床成因 成矿物质来源 |
| 收稿时间： | 2021/9/6 0:00:00 |
| 修稿时间： | 2021/11/20 0:00:00 |
Metallogenic age and genesis of the Zhaishang gold deposit in Minxian, Gansu Province |
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| WANG YuHao,DU ZhiWei,JIAO XueYao,MA JinLong.Metallogenic age and genesis of the Zhaishang gold deposit in Minxian, Gansu Province[J].Acta Petrologica Sinica,2022,38(4):1237-1252. |
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| Authors: | WANG YuHao DU ZhiWei JIAO XueYao MA JinLong |
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| Institution: | School of Earth Sciences, Lanzhou University, Lanzhou 730000, China;Geological Survey of Gansu Province, Lanzhou 730000, China |
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| Abstract: | Zhaishang gold deposit is located in the concentrated area of large-scale carlin-like gold deposits in West Qinling Mountains, and it is the second super-large gold deposit discovered in the past 20 years. Rb, Sr, Re, Os isotopes of the pyrite, the gold-bearing mineral of Zhaishang gold deposit, in six ore samples were tested in this paper to determine their metallogenic ages and ore-forming materials. The measured Rb-Sr and Re-Os isochron ages of the pyrite are 273±10Ma and 273Ma±22Ma, which are older than the ages of two metallogenic stages of the Zhaishang deposit obtained by the predecessors, i.e., a earlier metallogenic stage (the first stage of 273Ma) might be exist in this area. This new chronological data may broaden the time axis for searching gold deposits in this area since no same metallogenic ages have ever been reported in the explored gold deposits in West Qinling. Furthermore, analyses results of Sr, Os, S isotopes, REE and trace elements compositions indicate that the ore-forming material of the Zhaishang gold deposit is the mixture of deep source and crust source materials. Tectonically, the Wujiashan Rise which is located in the Minli fore-arc basin experienced a strong geothermal uplift and extension in the Late Hercynian Period, which resulted in the hydrothermal fluids rising along the fault channels to the folded belts of the basin with a high Au background, and the activated Au enriched in the formation and unloaded in suitable structural spaces to form the first stage Zhaishang gold deposit. The later two stages of W and Au mineralization superimposed on the early gold deposit. Compared with regional geological evolutionary events, the age of gold mineralization in the first stage of Zhaishang gold deposit is consistent with the time of the closure of the A''nyemaqen ocean basin in the West Qinling, the subduction collision of Gonghe aulacogen, and the intrusion of Jiangligou and Zhongchuan Himalayan-type plutons, which obeys the rule "crustal thickening is conducive to the formation of gold deposits and Himalayan granites are closely related to gold deposits". It is of indicative significance for searching contemporary gold deposits in this area. |
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| Keywords: | Zhaishang gold deposit Metallogenic age Metallogenic stages Genesis of the deposit Ore-forming materials |
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