Geological characteristics and prospecting direction of typical Cu-Co deposits in Northwestern Province, Zambia
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摘要:
卢菲利安弧是全球极为重要的铜钴成矿带,赞比亚西北省铜-金-钴-镍-铀成矿亚带为该成矿带的重要组成部分,但其基础地质工作薄弱,缺乏系统的成矿机制研究。通过水系沉积物地球化学、土壤地球化学、地球物理特征和典型矿床研究,总结梳理了赞比亚西北省的成矿地质演化和成矿规律,提出区域找矿方向,以期在该地区实现找矿新突破。卢菲利安弧穹窿区主要分布于赞比亚西北省内,产有铜、金、钴、铀、镍等重要金属矿种,含矿岩层为罗安群炭质页岩、千枚岩,成矿类型主要为变质热液脉型,矿床成因为在泛非期NW—SE向挤压作用下,成矿物质活化,含矿热液沿断裂迁移,因物理化学条件改变沉淀、富集成矿;复向斜带南缘希富玛IOCG型铜-金-钴矿赋存于NE向的含铜碳酸岩中,矿床成因为初始地幔物质沿深大断裂上升至地壳浅部过程中,由于温度和压力下降,初始岩浆不断演化并最终成矿。通过研究赞比亚西北省典型矿床的成因和成矿模式,提出未来找矿方向应注重在穹窿区基底周缘推覆带内寻找受构造和地层双重控矿的铜-金-铀矿,在复向斜带内的构造岩浆带内应充分利用航磁异常、化探异常来寻找NW向深断裂与NE向断裂交会部位的(碳酸岩型)IOCG型铜-金-钴-银-铁矿。
Abstract:The Luffilian Arc is an extremely important Cu-Co mineralization belt in world, and the Cu-Au-Co-Ni-U mineralization subzone in the Northwestern province of Zambia is an important component of Luffilian Arc.However, its basic geological work is fewer and is lack of systematic research on mineralization mechanisms.Based on the research on the geochemical characteristics of river sediments, soil geochemical characteristics, geophysical characteristics and typical Cu-Co deposits, this paper summarizes the metallogenic geological evolution and metallogenic of Northwestern province of Zambia, and proposes the regional prospecting direction, to achieving in more Cu-Co deposits in this area.The Dome area of Luffilian Arc is mainly distributed in Northwestern province of Zambia, producing copper, gold, cobalt, uranium, nickel and other important metal minerals.The ore bearing strata are carbonaceous shale and phyllite of the Roan Group, and the mineralization type is mainly metamorphic hydrothermal vein type.The ore deposit is formed because of the activation of ore-forming materials and the migration of ore bearing hydrothermal fluid along the fault under the Pan African NW-SE compression, and the precipitation and enrichment of ore-forming due to the change of physical and chemical conditions; The Shivuma IOCG type Cu-Au-Co deposit in the southern margin of the syncline belt occurs in the NE trending copper bearing carbonatite.The deposit is formed because the initial mantle rises along the deep fault to the shallow crust.Due to the temperature and pressure drop, the initial magma continues to evolve and mineralize eventually.By researching the genesis and metallogenic model of the typical deposits in northwest Zambia, it is proposed that the future prospecting direction should find the Cu-Au-Co deposits controlled by both structure and strata in the nappe belt around the basement of the Dome area, and utilizing aeromagnetic anomalies and geochemical anomalies in the tectono magmatic belt in the syncline zone to find IOCG type Cu-Au-Co-Ag-Fe deposits at the intersection of NW trending deep faults and NE trending faults.
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Key words:
- geological characteristics /
- prospecting direction /
- typical deposit /
- Cu-Co /
- Zambia
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图 1 赞比亚西北省区域地质与主要矿床分布简图(据Sikatali et al., 1994)
Figure 1.
图 2 赞比亚姆维尼伦加地区地质图和铜地球化学异常图(据Key et al., 2001)
Figure 2.
图 4 赞比亚坎桑希铜-金矿地质简图(a)和剖面(b) (据张东红等, 2013a; 肖波等, 2014)
Figure 4.
图 5 卡伦比拉矿区地质简图(a, 据张东红等,2013a)和卡伦比拉项目典型剖面(b,据Steven et al., 2003)
Figure 5.
表 1 赞比亚西北省铜钴矿床成矿时代
Table 1. Geochronology of Cu-Co deposits in Northwestern Province, Zambia
矿床名称 矿床类型 测试方法 测试对象 测试结果 资料来源 卢阿玛塔(Luamata) 沉积-改造型铜钴矿 750~710 Ma Steven,2000;Schmandt et al., 2013 卡伦比拉(Kalumbila) 变质热液铜镍矿 SHRIMP U-Pb 独居石
金红石548.6±7.6 Ma
531±21 MaSteven et al., 2003 坎桑希(Kansanshi) 变质热液脉型铜金矿 Re-OS 辉钼矿 512.4±1.2 Ma
502.4±1.2 MaTorrealday et al., 2000 SHRIMP U-Pb 独居石 511±11 Ma 希富玛(Shivuma) 铁氧化物型(IOCG)铜矿 LA-ICP-MS
U-Pb锆石 537.2±7.6 Ma
529±16 Ma边千韬等, 2017 胡克(hook)花岗岩 岩体 LA-ICP-MS
U-Pb锆石 566~519 Ma 古阿雷等, 2020 -
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