| 西非矿产资源的地质背景及重要成矿分区 |
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| 引用本文： | 张继纯,严永祥,王建雄,毛晓冬.西非矿产资源的地质背景及重要成矿分区[J].华南地质与矿产,2019,35(1):76-89. |
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| 作者姓名： | 张继纯 严永祥 王建雄 毛晓冬 |
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| 作者单位： | 中国地质调查局武汉地质调查中心(中南地质科技创新中心),武汉,430205;成都理工大学,成都,610059 |
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| 基金项目： | 中国地质调查项目;中国地质调查项目;北部非洲大型铜金资源基地评价资助 |
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| 摘 要： | 西西非地区蕴藏着丰富的矿产资源,尤其以产出众多大型超大型的铝土矿、铁矿、金矿、金刚石矿等著称,在全球占有重要地位。矿床集中分布在三个构造域内,形成于不同的成矿期:(1)太古宙马恩(Man)地盾和雷圭巴特(Reguibat)地盾、古元古界莱奥(Leo)地盾及凯涅巴(Kéniéba)和卡伊(Kayes)构造窗,主要成矿事件包括在2.5-2.3Ga形成了多个巨型铁矿床;几乎所有金矿、斑岩型铜矿、铅锌矿和沉积型锰矿都形成于2.2-2.1Ga;原生金刚石矿床形成于两个时间段,分别是2.2-2.0Ga左右和中生代。(2)泛非期和海西期活动带成矿域,主要成矿事件包括前寒武纪2.1Ga左右以及680Ma左右发生的铁氧化物铜金矿床(IOCG)成矿事件,以及新元古代沉积型铁矿和磷矿。(3)克拉通内盆地和海岸盆地带,包括新生代在中生代辉绿岩之上发生的铝土矿化作用,新近纪/第四纪形成的砂矿床、鲕状铁矿床和沉积型磷矿。西非地区的矿产分布规律与成矿时代、赋矿岩石、区域构造密切相关,不同矿种区域集中分布特征明显。根据已发现的铁矿、铝土矿、金矿、金刚石矿等主要经济矿产的分布,结合区域地质背景等因素,在西非克拉通南部划分了3个重要成矿区:(1)马恩太古宙地盾铁、金刚石巨型成矿区;(2)莱奥古中元古界地盾(包括凯涅巴构造窗)金矿等巨型成矿区;(3)博韦(Bove)新元古-古生代盆地铝土矿巨型成矿区。这些巨型成矿区也是西非地区最重要的矿产地和成矿远景区。
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| 关 键 词： | 西非 地质背景 铁矿 金刚石 金矿 铝土矿 巨型成矿区 |
Geological Background and Important Metallogenic Divisions of Mineral Resources in Western Africa |
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| ZHANG Ji-Chun,YAN Yong-Xiang,WANG Jian-Xiong,MAO Xiao-Dong.Geological Background and Important Metallogenic Divisions of Mineral Resources in Western Africa[J].Geology and Mineral Resources of South China,2019,35(1):76-89. |
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| Authors: | ZHANG Ji-Chun YAN Yong-Xiang WANG Jian-Xiong MAO Xiao-Dong |
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| Institution: | (Wuhan Center of China Geological Survey (Central South China Innovation Center for Geosciences), Wuhan 430205,Hubei,China;Chengdu University of Technology,Chengdu 610059, Sichuan,Hubei) |
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| Abstract: | West Africa is rich in mineral resources, especially in the production of large and super-large bauxite, iron ore, gold, diamond and so on, which occupies an important position in the world. The deposits are concentrated in three tectonic domains and formed in different metallogenic stages:(1) Archean Man shield and Reguibat shield, Paleoproterozoic Leo shield and Kéniéba and Kayes structural window, The main metallogenic events include the formation of several huge iron deposits in 2.5-2.3 Ga;almost all gold deposits, porphyry copper deposits, lead-zinc deposits and sedimentary manganese deposits were formed in 2.2-2.1 Ga, while primary diamond deposits were formed in 2.2-2.0 Ga and Mesozoic respectively.(2) In the Pan-African and Hercynian active metallogenic domains, the main metallogenic events include the occur rence of iron oxide copper-gold deposits (IOCG) in the Precambrian around 2.1 Ga and 680 Ma respectively, as well as the Neoproterozoic sedimentary iron ore and phosphorus deposits.(3) The intracratonic basins and coastal basin belts include bauxite mineralization over Mesozoic diabase in Cenozoic, ancient placer type deposits, oolitic iron deposits and sedimentary phosphate deposits formed in Tertiary/Quaternary. The distribution of mineral resources in West Africa is closely related to metallogenic epoch, ore-hosting rocks and regional structure, and the regional concentration distribution characteristics of different mineral species are obvious. According to the distribution of major economic minerals such as iron ore, bauxite, gold and diamond deposits, and combined with regional geological background, three important metallogenic areas are divided in the southern part of West African craton:(1) Archean shield iron and diamond mega-metallogenic areas in Man shield;(2) Mesoproterozoic Leo shield (including Kaneba structural window) gold deposits;(3) Bowe Neoproterozoic-Paleozoic basin bauxite giant metallogenic area. These mega-metallogenic areas are also the most important mineral resources and metallogenic prospects in West Africa. |
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| Keywords: | West Africa geological background iron deposits diamonds gold deposits bauxite deposit mega-metallogenic area |
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