地球化学块体法在埃塞俄比亚铜矿资源评价中的应用  

Application of the geochemical block method to the assessment of copper resources in Ethiopia

作　　者：向文帅 白洋 姜军胜 雷义均 HUNDIE Melka SISAY Degu 张元培 吴颖 郑雄伟 XIANG Wen-Shuai;BAI Yang;JIANG Jun-Sheng;LEI Yi-Jun;HUNDIE Melka;SISAY Degu;ZHANG Yuan-Pei;WU Ying;ZHENG Xiong-Wei(Wuhan Center,China Geological Survey,Central South China Innovation Center for Geosciences,Wuhan 430205,China;Geophysical Exploration Brigade,Hubei Geological Bureau,Wuhan 430056,China;Ethiopian Geological Survey,Addis Ababa 999047,Ethiopia)

机构地区：[1]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),湖北武汉430205 [2]湖北省地质局地球物理勘探大队,湖北武汉430056 [3]埃塞俄比亚地质调查局,亚的斯亚贝巴999047

出　　处：《物探与化探》2023年第4期845-855,共11页Geophysical and Geochemical Exploration

基　　金：中国地质调查局地质调查项目(DD20190443,DD20160109)。

摘　　要：低密度地球化学填图具有采样水系级别高、工作覆盖面积广阔的特征,可有效追溯具有高金属含量的地球化学块体。本次研究以埃塞俄比亚1∶100万低密度地球化学填图数据为基础,通过对原始水系沉积物中Cu测试数据处理后,应用迭代剔除的方法,计算得出Cu的异常下限值为37×10^(-6)。在此基础上,以37×10^(-6)、42×10^(-6)、47×10^(-6)、52×10^(-6)、59×10^(-6)、66×10^(-6)作为分级间隔,共圈定出地球化学块体3个、区域异常2个。通过参考相同成矿带中铜矿勘查研究程度较高的地球化学块体中已知铜矿床储量,计算出研究区的Cu块体成矿率为0.055%。本次以1000 m岩块厚度估算出研究区内Cu的资源量为260万t。结合区域成矿地质条件分析,确定2号、3号、4号地球化学块体所在区域可作为开展进一步详细勘查工作的重点成矿远景区。Low-density geochemical mapping is characterized by high order streams to be sampled and a large coverage area and can be used to effectively trace geochemical blocks with high metal contents.Based on the 1∶1,000,000 low-density geochemical mapping data of Ethiopia and the processing of the testing data of Cu in the original stream sediments,this study calculated the anomaly threshold of Cu at 37×10^(-6)through iterative deletion.Then,this study delineated three geochemical blocks and two regional anomalies with 37×10^(-6),42×10^(-6),47×10^(-6),52×10^(-6),59×10^(-6),and 66×10^(-6)as grading intervals.It calculated the mineralization coefficient of Cu ore bodies in the study area at 0.055%by referencing the known reserves of Cu deposits in geochemical blocks with a high level of copper exploration in the same metallogenic belt.Moreover,this study estimated the Cu resources in the study area at 2,600,000 t based on a rock mass thickness of 1,000 m.By combining the analysis of metallogenic geological conditions,this study determined that the zones where geochemical blocks nos.2,3,and 4 are located can be considered key metallogenic prospect areas for further detailed explora-tion.

关 键 词：埃塞俄比亚 铜 地球化学块体 资源潜力 成矿远景区 

分 类 号：P632[天文地球—地质矿产勘探]