地学前缘 ›› 2024, Vol. 31 ›› Issue (3): 170-198.DOI: 10.13745/j.esf.sf.2023.2.78

• 金属成矿作用与成矿预测 • 上一篇    下一篇

试论中亚造山带东部多宝山矿田斑岩铜-浅成低温金系统成矿特征与矿床模型

柏铖璘1(), 谢桂青1,2,3,*(), 赵俊康4, 李伟1, 朱乔乔2   

  1. 1.中国地质大学(北京) 地球科学与资源学院, 北京 100083
    2.中国地质科学院 矿产资源研究所, 北京 100037
    3.自然资源部战略性金属矿产找矿理论与技术重点实验室, 北京 100083
    4.紫金矿业集团股份有限公司 矿产地质勘查院, 福建 厦门 361000
  • 收稿日期:2023-02-02 修回日期:2023-07-18 出版日期:2024-05-25 发布日期:2024-05-25
  • 通信作者: *谢桂青(1975—),男,教授,博士生导师,从事矿床模型与找矿预测的研究工作。E-mail: xieguiqing@cugb.edu.cn
  • 作者简介:柏铖璘(1997—),男,博士研究生,矿床学专业。E-mail: 3057220016@email.cugb.edu.cn
  • 基金资助:
    国家重点研发计划项目(2022YFC2903601);国家杰出青年科学基金项目(41925011)

Metallogenic characteristics and ore deposit model of porphyry copper-epithermal gold system in the Duobaoshan ore field, eastern margin of the Central Asian Orogenic Belt

BAI Chenglin1(), XIE Guiqing1,2,3,*(), ZHAO Junkang4, LI Wei1, ZHU Qiaoqiao2   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
    2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
    3. MNR Key Laboratory for Exploration Theory & Technology of Critical Mineral Resources, Beijing 100083, China
    4. Institute of Geology and Mineral Exploration, Zijin Mining Group Co., LTD, Xiamen 361000, China
  • Received:2023-02-02 Revised:2023-07-18 Online:2024-05-25 Published:2024-05-25

摘要:

多宝山矿田位于中亚造山带东段,是目前我国东北地区规模最大、成矿时代最老(477~470 Ma)的斑岩铜钼-浅成低温热液金成矿系统,已探明铜、钼、金储量分别可达5 Mt、0.16 Mt和130 t。从成矿系统角度,其成矿特征和矿床模型尚不清晰。本文系统分析了矿床的地质地球化学特征和成矿时代,发现该成矿系统存在两期成矿事件,以第一期为主,发生在早奥陶世;第二期为叠加成矿,发生在晚三叠世。成矿作用具有下部为隐爆角砾状铜矿化、中部为脉状铜矿化、上部为金矿化的空间结构特征,围岩蚀变从中心向两侧依次为钾化-黑云母化带、青磐岩化带、黏土化带、碳酸盐化带、绢英岩化带和硅化带。成矿流体主要来源于岩浆水,从多宝山斑岩铜矿到争光浅成热液金矿床呈现大气水加入比例增大的趋势。根据第一期成矿斑岩具有高Ce4+/Ce3+(174~461;均值约290)、高 f O 2埃达克质岩浆特征,进一步得出主成矿期与古生代古亚洲洋俯冲作用相关的壳幔混源岩浆作用有关。成矿受古火山机构所制约,其北西到南东成矿深度增大与剥蚀程度相关,受铜山逆断层作用效应,暗示铜山断层以南为较好的找矿靶区。最后,本文建立了该区古生代斑岩铜-浅成低温热液金成矿系统的矿床模型,以期为该区进一步矿产勘探提供借鉴。

关键词: 斑岩铜-浅成低温热液金成矿系统, 古生代大规模成矿, 成矿特征, 成矿模型, 多宝山矿田, 中亚造山带东部

Abstract:

The Duobaoshan ore field, situated in the eastern part of the Central Asian Orogenic Belt (CAOB), represents the largest porphyry Cu (Mo)-epithermal Au metallogenic system with an ancient mineralization age (477-470 Ma) in Northeast China. The reserves of copper, molybdenum, and gold resources have been preliminarily estimated to be over 5 Mt, 0.16 Mt, and 130 t, respectively. Despite this, the metallogenic characteristics and ore deposit model of this system remain unclear. This study comprehensively analyzes the geological, geochemical characteristics, and timing of the deposit. It suggests the presence of two mineralization events in the metallogenic system: the primary episode, occurring in the early Ordovician, and a subsequent superimposed mineralization event in the late Triassic. The mineralization exhibits spatial zonation, with explosive brecciated copper mineralization in the lower part, vein copper mineralization in the middle part, and gold mineralization in the upper part. Wall-rock alteration progresses from the center to both sides or from early to late, transitioning through potassic-biotite, propylitic, clay, carbonate, phyllic, and silicification alteration zones. The ore-forming fluids are identified as magmatic water, transitioning from porphyry copper to epithermal gold deposits or from Duobaoshan to Zhengguang deposits, with a trend of increasing proportions of meteoric water. The high Ce4+/Ce3+ ratios (174-461; average 290) and high f O 2 characteristics of the adakitic magma suggest a main mineralization related to crust-mantle mixed-sourced magmatism linked to the subduction of the Paleozoic Paleo-Asian Ocean. Mineralization is controlled by ancient volcanic mechanisms, and the increase in metallogenic depth from northwest to southeast is associated with denudation levels. The presence of the Tongshan reverse fault influences mineralization, indicating the south of the Tongshan fault as a promising exploration target. Furthermore, an ore deposit model for the Paleozoic porphyry copper-epithermal gold system in this region is proposed to guide future mineral exploration efforts.

Key words: porphyry copper-epithermal gold metallogenic system, Paleozoic large-scale mineralization, metallogenic characteristics, ore deposit model, Duobaoshan ore field, eastern Central Asian Orogenic Belt

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