地学前缘 ›› 2018, Vol. 25 ›› Issue (5): 96-118.DOI: 10.13745/j.esf.sf.2018.4.2

• 中亚造山带地质事件与成矿 • 上一篇    下一篇

东准噶尔北缘老山口铁铜金矿床古生代岩浆岩锆石U-Pb年代学、氧逸度特征及地质意义

梁培，陈华勇，吴超，刘振江   

  1. 1. 中国科学院 广州地球化学研究所 矿物学与成矿学重点实验室, 广东 广州 510640
    2. 中国科学院大学, 北京 100049
    3. 新疆地质矿产开发局 第四地质大队, 新疆 阿勒泰 831140
  • 收稿日期:2018-02-08 修回日期:2018-04-12 出版日期:2018-09-15 发布日期:2018-09-15
  • 作者简介:梁培(1990—)，女，博士研究生，矿物学、岩石学、矿床学专业。E-mail:liangpei@gig.ac.cn；liangpei1990@gmail.com
  • 基金资助:
    国家重点基础研究发展计划“973”项目(2014CB440802)；中国科学院交叉学科项目(Y433131A07)；中国科学院创新团队国际合作项目(20140491534)

Geochemistry, geochronology and oxygen fugacity of volcanic and intrusive rocks from the Laoshankou Fe-Cu-Au deposit in the northern margin of East Junggar, NW China.

LIANG Pei，CHEN Huayong，WU Chao，LIU Zhenjiang   

  1. 1. Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. No.4 Geological Party of the Xinjiang Bureau of Geology and Mineral Exploration and Development, Altay 836500, China
  • Received:2018-02-08 Revised:2018-04-12 Online:2018-09-15 Published:2018-09-15

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摘要： 老山口矿床位于新疆东准噶尔北缘，是区域内重要的铁铜金矿床。矿区内岩浆岩发育广泛，对其中的奥陶纪玄武安山岩(约449 Ma)，奥陶纪安山岩(约447 Ma)，泥盆纪火山岩(393~376 Ma)、二长闪长岩(约379 Ma)、黑云母闪长岩(约379 Ma)、石英正长岩(约376 Ma)、细粒闪长岩(约370 Ma)，石炭纪碱性花岗岩(约330 Ma)和粗粒闪长玢岩(约310 Ma)进行了成岩年代学的统计和测试，结果表明老山口矿床存在3期岩浆活动：450~440 Ma、约390~370 Ma以及330~310 Ma。结合区域构造演化可知，其中450~440 Ma和390~370 Ma的岩浆活动形成于不同时期俯冲相关的岛弧环境，而330~310 Ma的岩浆活动则形成于后碰撞板内伸展环境。根据铜金矿化的时代，可将矿区内的岩浆岩分为3期：成矿前、同成矿及成矿后。老山口同成矿期岩浆岩(泥盆纪火山岩、二长闪长岩、闪长玢岩和黑云母闪长岩)具有相对较高的(Eu/Eu*)N、(Ce/Ce*)N和CeⅣ/CeⅢ值，分别为0.13~0.86、1.14~445.92和33.34~1 165.04，说明铁铜金矿化与高氧逸度的岩浆活动有关。

关键词: 东准噶尔北缘, 老山口铁铜金矿床, 锆石U-Pb年代学, 锆石微量元素, 氧逸度

Abstract: The Laoshankou deposit is an important Fe-Cu-Au deposit in the northern margin of the East Junggar, NW China. LA-ICP-MS U-Pb dating of zircon constrains the timing of crystallization of Ordovician basaltic andesite (~449 Ma), Ordovician andesite (~447 Ma), Devonian volcanic rocks (393376 Ma), monzodiorite (~379 Ma), biotite diorites (~379 Ma), quartz syenites (~376 Ma), fine-grained diorite (~370 Ma), alkali granite (~330 Ma) and coarse-grained diorite porphyry (~310 Ma). Zircon dating indicates three periods of magmatism in Laoshankou: 450440 Ma, ~390370 Ma and 330310 Ma. The magmatism for the first two periods occurred in a subduction-related island arc setting; the magmatism for the last one occurred in a post-collision or inplate extensive setting. Pre-, syn- and post-mineralization volcanic and intrusive rocks are divided based on the Fe-Cu-Au mineralization timing. Syn-mineralization intrusions in Laoshankou have relatively high (Eu/Eu*)N, (Ce/Ce*)N and CeIV/CeIII values of 0.130.86, 1.14445.92 and 33.341165.04, respectively, indicating Fe-Cu-Au mineralization was associated with high oxygen fugacity magmatism.

Key words: northern margin of East Junggar, Laoshankou Fe-Cu-Au deposit, zircon U-Pb geochronology, zircon trace elements, oxygen fugacity

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