| 刚果(金)绿纱铜钴矿床黑色页岩Rb-Sr测年及其区域成矿意义 |
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| 引用本文： | 高帮飞,沈阳,钟长汀,马恒,张作伦.刚果(金)绿纱铜钴矿床黑色页岩Rb-Sr测年及其区域成矿意义[J].地质学报,2021,95(4):1029-1049. |
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| 作者姓名： | 高帮飞 沈阳 钟长汀 马恒 张作伦 |
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| 作者单位： | 中铁资源集团有限公司,北京,100039,中国;MKM矿业股份有限公司,科卢维齐,20043,刚果(金);金诚信矿业管理股份有限公司,北京,100070,中国;中铁资源集团有限公司,北京,100039,中国;绿纱矿业股份有限公司,卢本巴西,20043 ,刚果(金);TFM矿业股份有限公司,科卢维齐,20043 ,刚果(金) |
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| 基金项目： | 本文为国外矿产资源风险勘查专项资金项目（编号201120B04700102）和中铁资源集团有限公司科技项目（编号2012- 重点- 02和2016- 重点- 04）共同资助的成果。 |
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| 摘 要： | 中非铜钴矿带是全球最大最具经济价值的沉积型层状铜成矿带之一.区域内铜钴矿床形成分布主要受区域地层和构造控制,成矿具有多期特征.含矿地层中发育大量褶皱前浸染状和顺层脉状矿化,指示可能存在成岩之后和造山主构造变形之前的矿化叠加作用.本文通过绿纱铜钴矿床矿化黑色页岩全岩Rb-Sr测年及Sr-Nd同位素研究,获得早期浸染状矿化黑色页岩等时线年龄为742±32Ma(MSWD=0.39),与木瓦夏-恩古巴裂谷作用同期;晚期脉状矿化黑色页岩及与脉体中白云石、黄铜矿单矿物构成的内部等时线年龄分别为680±24Ma(MSWD=0.95)和678±21Ma(MSWD=1.5),为刚果克拉通与卡拉哈里克拉通俯冲造山作用初期.Sr,Nd同位素特征显示,早期浸染状矿化成矿物质来源长英质基底和同期基性火山岩;晚期脉状矿化成矿物质来源基性基底和赋矿围岩,与盆地内循环热卤水成矿有关.大量证据表明,顺层脉状矿化及其伴生切层脉状和角砾岩状矿化具有三维空间上的连通性,为同期矿化作用产物.脉体的形成与区域挤压作用引起的超高压流体水压致裂和侧向流动有关,区域挤压应力的动力来源于俯冲造山作用.700Ma左右,罗迪尼亚超大陆裂解结束及冈瓦纳超大陆聚合开始,引起区域构造体制从伸展向挤压转换,可能是区域大规模叠加成矿作用发生的地球动力学机制.
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| 关 键 词： | Rb-Sr测年 黑色页岩 绿纱铜钴矿床 中非铜钴矿带 刚果(金) |
| 收稿时间： | 2020/6/19 0:00:00 |
| 修稿时间： | 2020/7/25 0:00:00 |
Rb- Sr dating of the black shale and its significance for regional metallogenesis, Luishia Cu- Co deposit, D R Congo |
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| GAO Bangfei,SHEN Yang,ZHONG Changting,MA Heng,ZHANG Zuolun.Rb- Sr dating of the black shale and its significance for regional metallogenesis, Luishia Cu- Co deposit, D R Congo[J].Acta Geologica Sinica,2021,95(4):1029-1049. |
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| Authors: | GAO Bangfei SHEN Yang ZHONG Changting MA Heng ZHANG Zuolun |
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| Abstract: | The Central African Copper Cobalt Belt is one of the largest and the most economically viable sediment- hosted stratiform Copper belt. The formation and distribution of Cu- Co deposits was controlled by the regional sedimentary rocks and tectonics, and the mineralization has multistage characteristics. A large number of pre- folding, disseminated and bedding, parallel vein- hosted mineralization indicates that there might be a superposition of mineralization after the diagenesis prior to the orogenic tectonic deformation.By using the whole rock Rb- Sr dating and Sr- Nd isotopic tracing,this paper obtained anisochronal age of 742±32Ma (MSWD=0. 39) of the early disseminated mineralized black shale, which is the same age as the Mwashya- Nguba rifting. The late veined mineralized black shale and the internal isochronous line constituted with the dolomite and chalcopyite in the veins yields ages of 680±24Ma (MSWD=0.95) and 678±21Ma (MSWD=1. 5) respectively, which are consistent with the early stage of subduction orogeny caused by Congo- Karahari Craton convergence. Based on the Sr and Nd isotopic characteristics, it is suggested that orematerial in the early disseminated mineralization came from felsic basement and contemporaneous mafic volcanic rocks. However, the metal inthe late vein- hosted mineralization was derived from mafic basement and host rocks, and related to the mineralization of circulating hot brines in the basin.Moreover, field evidence indicates that bedding parallelling vein- hosted mineralization and its associated transgressive veins, and brecciated mineralization with the three- dimensional connectivity are the products of contemporaneous mineralization. These veins weregenetically related to the hydraulic fracturing and lateral excursion of overpressured fluids caused by regional compression that was driven by subduction orogeny. In such context, the end of Rodinia breakup and the beginning of Gondwana assembly around 700Ma resulted in the transformation of regional tectonic regime from extension to compression, which might be the geodynamic mechanism of regional large- scale superposition of Cu mineralization. |
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| Keywords: | Rb- Sr dating black shale Luishia Cu- Co deposit Central African Copper Cobalt Belt D R Congo |
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