Application of Geochemical Block Method in the Potential Prediction of Copper Resources in Eritrea
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摘要: 新元古代东非造山运动在厄立特里亚阿拉伯-努比亚地盾区形成了大面积出露的变质火山沉积岩系及相应的花岗质岩浆岩，与之相关的铜矿资源非常丰富。本文以厄立特里亚1︰100 万水系沉积物地球化学数据样本为基础，应用地球化学块体理论，对该国铜资源潜力进行预测。厄立特里亚共圈定地球化学块体7 个，地球化学区域异常5 个，地球化学块体的铜元素异常下限值为28×10-6。根据不同成矿带内已知铜矿床的资源量推算各区块铜的成矿率，以1 km矿床勘探深度为准则预测各区块潜在铜金属量，估算出厄立特里亚潜在铜资源为930.76 万吨。其中，5、6 号铜地球化学块体可作为下一步铜矿勘查的重点区域，1、2、3、4、7号铜地球化学块体的找矿潜力也值得注意。Abstract: The Neoproterozoic East African orogeny formed a large area of exposed metavolcanic sedimentary rock series and corresponding granitic magmatic rocks in the Arab-Nubian Shield, Eritrea, in which the copper resource is very rich. In this paper, 1:1000000 stream sediment geochemical data in Eritrea was selected as the research object. Based on the theory of geochemical block method, we synthetically evaluated the Cu resource potential of Eritrea. The result of geochemical data shows that the value of geochemical anomaly threshold is 28×10-6. Seven geochemical blocks and five regional anomalies were delineated. According to the reserves of known deposits in different metallogenic belts, the mineral coefficient of Cu in each areawas calculated. The total copper tonnage and mineral resources in each area were calculated based on the exploration depth of the 1km. Thus, we inferred that the total copper tonnage in the 7 geochemical blocks and 5 regional geochemical anomalies of Eritrea (given a 1 km thickness of every rock mass) is 9.3076 million tons. Among them, geochemical blocks 5 and 6 should be used as the focus of the next step, and the exploration potential in geochemical blocks 1, 2, 3, 4 and 7 should also be noted.
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Key words:
- geochemical block /
- copper deposit /
- mineral resources forecast /
- Eritrea
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