地学前缘 ›› 2020, Vol. 27 ›› Issue (2): 373-390.DOI: 10.13745/j.esf.sf.2020.3.27

• 矿床地质地球化学 • 上一篇    下一篇

山西梨园金矿黄铁矿微量元素及S-Pb-He-Ar同位素地球化学特征及其地质意义

甄世民1,2,3(), 庞振山1,2,*(), 朱晓强3, 薛建玲1,2, 方永财4, 贾宏翔3, 石光耀3, 王大钊3, 查钟健3, 宋晓航3   

  1. 1.中国地质调查局 发展研究中心, 北京 100037
    2.自然资源部 矿产勘查技术指导中心, 北京 100083
    3.中国地质大学(北京) 地质过程与矿产资源国家重点实验室, 北京 100083
    4.梨园金矿有限责任公司, 山西 灵丘 034403
  • 收稿日期:2019-11-16 修回日期:2019-12-18 出版日期:2020-03-25 发布日期:2020-03-25
  • 通讯作者: 庞振山
  • 作者简介:甄世民(1984─),男,高级工程师,主要从事矿床学和矿床地球化学研究。E-mail: zhenshimin0001@163.com
  • 基金资助:
    中国地质调查局地质矿产调查与评价专项“全国重要矿集区找矿预测”(DD20160052);“重要锡、锰等矿集区矿产地质调查”(DD20190166);“矿集区矿产调查及深部找矿预测”(DD20190570)

The characteristics of trace elements and S, Pb, He and Ar isotopes in the Liyuan gold deposit in Shanxi Province, and their significance

ZHEN Shimin1,2,3(), PANG Zhenshan1,2,*(), ZHU Xiaoqiang3, XUE Jianling1,2, FANG Yongcai4, JIA Hongxiang3, SHI Guangyao3, WANG Dazhao3, ZHA Zhongjian3, SONG Xiaohang3   

  1. 1. Development and Research Center, China Geological Survey, Beijing 100037, China
    2. Technical Guidance Center for Mineral Resources Exploration, Ministry of Natural Resources, Beijing 100083, China
    3. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences(Beijing), Beijing 100083, China
    4. Liyuan Gold Mine Limited Liability Company, Lingqiu 034403, China
  • Received:2019-11-16 Revised:2019-12-18 Online:2020-03-25 Published:2020-03-25
  • Contact: PANG Zhenshan

摘要:

山西梨园金矿是近年华北克拉通内部金矿找矿的新进展,其矿化样式多,具有较高的研究价值。梨园金矿赋存于太古宙阜平群片麻岩和混合岩化花岗岩中,受区内北北东向断裂控制,主要由爆破角砾岩型的1号矿体和石英脉型的2号矿体组成。矿石矿物主要为黄铁矿、方铅矿和闪锌矿等,脉石矿物主要为石英、绢云母、钾长石等,蚀变类型主要为硅化、钾长石化、绢云母化、绿泥石化等。黄铁矿、黄铜矿和闪锌矿δ34S值为0.9‰~4.3‰,平均值为3.0‰,说明硫源主要来自岩浆;方铅矿δ34S值为-12.8‰~1.4‰,平均值为-4.2‰,pH值升高可能是造成方铅矿高负δ34S值的原因。金属硫化物Pb同位素变化范围较小,206Pb/204Pb为16.697~16.890,207Pb/204Pb为15.239~15.267,208Pb/204Pb为42.186~45.334,均落入下地壳演化线附近,表明成矿流体运移过程中可能淋滤了富Th的下地壳物质。黄铁矿的3He/4He为0.27~1.04 Ra,40Ar/36Ar为1 194.61~5 488.80,38Ar/36Ar为0.204~0.218,表明成矿流体主要来源于地壳,部分来源于地幔流体,具有壳幔混合的岩浆流体特点。微量元素特征显示黄铁矿具有岩浆热液型黄铁矿的特点,辉绿岩脉和石英斑岩的部分物质可能加入了成矿过程。文章认为梨园金矿为与浅成岩浆侵入作用相关的岩浆热液型金矿床,爆破角砾岩型和石英脉型矿体不同的沉淀机制和矿物结晶过程是导致二者REE含量、S-Pb-He-Ar同位素等方面存在差异的主要原因。梨园金矿深部具有寻找细脉浸染型矿体的可能,其成矿作用是太行山中部地区燕山期构造岩浆活动的又一具体表现。

关键词: 微量元素, S-Pb-He-Ar同位素, 梨园金矿, 太行山中部

Abstract:

The Liyuan gold deposit is an exploration breakthrough at the inner North China Craton in recent years. It has many types of mineralization with high research values. The Liyuan gold deposit occurs in the archaean Fuping group gneiss and mixed rocked granite, controlled by the NNE fault in the area, and mainly consists of explosive breccia-type orebody and quartz vein-type orebody. Ore minerals are mainly pyrite, galena and sphalerite, while gangue minerals are mainly quartz, sericite and K-feldspar, and alteration is mainly silicification, K-feldspar, sericitization and chloritization.The δ34S values of pyrite, chalcopyrite and sphalerite are 0.9‰-4.3‰, with an average of 3.0‰, which indicates that the source of sulfur mainly comes from the magma fluids.The δ34S values of galena are -12.8‰-1.4‰, with an average of -4.2‰. The increase in pH value may be the cause of the high negative δ34S value of galena. The variation range of Pb isotopes of metal sulfides is relatively small, and206Pb/204Pb values are 16.697-16.890,207Pb/204Pb values are 15.239-15.267,208Pb/204Pb values are 42.186-45.334, all of which fall near the evolution line of the lower crust. These variations indicate that the ore-forming fluid may have drenched the rich lower crust materials during the migration process. The3He/4He of pyrite is 0.27-1.04 Ra,40Ar/36Ar is 1194.61-5488.80, and38Ar/36Ar is 0.204-0.218, which indicates that the ore-forming fluid is mainly from the crust and partly from the mantle fluid, with the characteristics of magma fluid mixed with the crust and mantle. The characteristics of trace elements indicate that pyrite has the characteristics of magmatic-hydrothermal pyrite, and some materials of diabase vein and quartz porphyry may have been involved in the mineralization process. In conclusion, the Liyuan gold deposit is considered to be the magmatic-hydrothermal gold deposit related to the shallow magmatic intrusion. And the difference in REE and S-Pb-He-Ar isotopes, between the two types, is mainly due to the different precipitation mechanisms and mineral crystallization processes of the explosive breccia-type and quartz vein-type orebodies. In the deep part of the Liyuan gold deposit, it is possible to search for the veinlet-disseminated orebodies, and its mineralization is another specific manifestation of Yanshanian tectono-magmatic activity in the central Taihang Mountains.

Key words: trace elements, S, Pb, He and Ar isotopes, Liyuan gold deposit, central Taihang Mountains

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