Application of fuzzy weights of evidence method in metallogenic prediction for alaskite-type uranium deposits in Namibia
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摘要:
纳米比亚埃龙戈地区位于达马拉构造带中部, 是全球重要的铀成矿带, 但纳米比亚第四系覆盖较重, 严重影响了铀矿找矿效果。为摸清纳米比亚铀资源现状, 开展铀资源潜力评价工作, 充分利用和深度挖掘现有资料, 圈定了预测靶区, 为中国矿业企业在海外投资提供支撑。在对纳米比亚埃龙戈地区白岗岩型铀矿床控矿因素系统总结的基础上, 建立了综合信息找矿模型; 在GeoDAS GIS平台上, 利用非线性理论、奇异性理论及分形滤波技术, 实现了对该区隐伏构造、航放铀异常等弱缓信息的提取; 基于模糊证据权方法开展综合信息矿产预测, 圈定铀找矿远景区7个。通过模型检验, 验证了本次预测工作的有效性。认为Ⅰ级远景区内第四系覆盖区还存在巨大的找矿潜力, Ⅱ级远景区也具有较好的成矿条件, 但工作程度较低, 有望实现找矿突破。
Abstract:The Erongo area of Namibia, located in the central of Damara tectonic belt, is an important uranium metallogenic belt in the world. However, the Quaternary coverage in Namibia is heavy, which seriously affects the prospecting effect of uranium deposits. In order to find out the status of uranium resources in Namibia, we have carried out the uranium resources potential evaluation, which has made full use of and deeply excavate the existing data, delineated the prediction target area, and provided support for Chinese mining enterprises to invest overseas. Based on the systematic summary of the ore-controlling factors of the alaskite-type uranium deposits in the Erongo area of Namibia, a comprehensive information prospecting model is established. On the GeoDAS GIS platform, nonlinear theory, singularity theory and fractal filtering technology are used to extract weak and slow information such as hidden structure and aero-released uranium anomaly in this area. Based on the fuzzy evidence weight method, the comprehensive information mineral prediction is carried out, and 7 uranium prospecting areas are delineated. The validity of this prediction is verified by model test. The paper holds that there is still huge prospecting potential in the Quaternary coverage area of the Grade Ⅰ prospect area, and the grade Ⅱ prospect area also has good ore-forming conditions, which is expected to achieve a breakthrough in prospecting because of the low working degree.
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表 1 纳米比亚埃龙戈地区白岗岩型铀矿找矿模型
Table 1. Table of prospecting model for alaskite-type uranium deposit in the Erongo area, Namibia
找矿要素分类 要素显示特征 区域成矿背景 区域构造 位于达马拉构造带，达马拉构造带为新元古代—早古生代形成的碰撞型造山带，主构造线方向以NE向为主，其次为NNE向断裂，其他方向断裂为从属构造 地球物理场 达马拉构造带南部中央区带为高磁区，其他为中低磁区；达马拉构造带南部中央区带具有高的铀钍背景值 地质找矿要素 地层 斯瓦科普群与诺西布群接触带，以及不同地层、岩性交界部位，如罗辛组/可汗组，或者楚斯组/可汗组接触界线附近。 构造 NE向、NNE向深断裂构造控制着白岗岩的展布，为U元素运移提供了通道，穹隆构造边部控制矿体就位 岩浆岩 D型或E型白岗岩脉 围岩蚀变组合 主要蚀变有高岭石化、伊利石化、硅化、黄铁矿化、绿帘石化和绿泥石化。与成矿关系最密切的是硅化、伊利石化、高岭石化 地球物理找矿要素 航磁 高磁区与穹隆构造吻合度高，航磁解译的NE向、NNE向断裂构造控制白岗岩的分布 航放 铀异常与矿床(点)吻合度高 
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表 2 纳米比亚埃龙戈地区有利预测变量
Table 2. Favorable prediction variable scale in the Erongo area, Namibia
编号 预测变量 有利度 1 断裂构造buffer分析 63%的矿床(点)分布于4 km缓冲区内 2 穹隆构造buffer分析 58%的矿床(点)分布于2 km缓冲区内 3 斯瓦科普群和诺西布群地层接触带buffer分析 68%的矿床(点)分布于2 km缓冲区内，大型矿床均距离接触带2 km以内 4 白岗岩(伟晶岩)脉buffer分析 白岗岩脉为赋矿主岩 5 铝羟基蚀变 伊利石化、高岭石化是非常重要的矿化蚀变标志 6 航放铀异常奇异性指数 异常点与已知矿床(点)吻合度高，矿体与异常吻合度高 7 航放铀增量 异常与已知矿床(点)吻合度高，同时有效去除高铀背景地质体的影响
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表 3 各证据图层隶属度(MSF)与模糊证据权计算
Table 3. Membership of each evidence layer(MSF) and calculation of fuzzy weights of evidence
图层 断裂buffer 穹隆buffer 地层接触带buffer 伟晶岩脉buffer 铝羟基蚀变 U异常奇异性指数 U增量 分类值Value 隶属度MSF 证据权重 隶属度MSF 证据权重 隶属度MSF 证据权重 隶属度MSF 证据权重 隶属度MSF 证据权重 隶属度MSF 证据权重 隶属度MSF 证据权重 1 1 1.36 1 2.19 1 2.44 1 2.87 1 1.72 1 2.44 - - 2 1 1.36 1 2.19 1 2.44 1 2.87 1 1.72 1 2.44 0 -1.43 3 1 1.36 1 2.19 1 2.44 1 2.87 1 1.72 1 2.44 0 -1.43 4 1 1.36 1 2.19 1 2.44 1 2.87 1 1.72 1 2.44 0 -1.43 5 1 1.36 1 2.19 1 2.44 1 2.87 - - 1 2.44 0 -1.43 6 1 1.36 0.83 2.03 0.86 2.23 0.83 2.74 - - 0.83 1.55 0 -1.43 7 1 1.36 0.67 1.85 0.71 1.98 0.67 2.63 - - 0.67 0.95 0 -1.43 8 1 1.36 0.5 1.62 0.57 1.73 0.5 2.51 - - 0.5 0.36 0 -1.43 9 0.6 1.14 0.17 0.98 0.43 1.44 0.17 2.3 - - 0.33 -0.28 0 -1.43 10 0.4 0.95 0 0.4 0.29 1.08 0 2.19 - - 0.17 -1.12 0.17 -0.79 11 0.2 0.62 0 0.4 0.14 0.56 0 2.19 - - 0 -8.9 0.33 -0.29 12 0 -0.16 0 0.4 0 -0.31 0 2.19 - - 0 -8.9 0.5 0.23 13 0 -0.16 0 0.4 0 -0.31 0 2.19 - - 0 -8.9 0.67 0.79 14 0 -0.16 0 0.4 0 -0.31 0 2.19 - - 0 -8.9 0.83 1.5 15 0 -0.16 0 0.4 0 -0.31 0 2.19 - - 0 -8.9 1 3.15 16 - - - - 0 -0.31 - - - - 0 -8.9 1 3.15 17 - - - - 0 -0.31 - - - - - - 1 3.15 18 - - - - 0 -0.31 - - - - - - 1 3.15 19 - - - - 0 -0.31 - - - - - - 1 3.15 20 - - - - 0 -0.31 - - - - - - - - 注：“-”表示无值
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[1] Agterberg F P. Computer programs for mineral exploration[J]. Science, 1989, 245(4913): 76-81. doi: 10.1126/science.245.4913.76
[2] Barnes J F H. Some aspects of the tectonic history of the Khan-Swakop region of the Damara Belt, Namibia[D]. Ph. D. Thesis, University of Leeds, 1981.
[3] Bonham-Carter G F. Geographic information systems forgeoscientists: Modelling with GIS[M]. Pergamon Press, Oxford, 1994: 1-398.
[4] Cheng Q M, Agterberg F P. Fuzzy weights of evidence method and its application in mineral potential mapping[J]. Natural Resources Research, 1999, 8(1): 27-35. doi: 10.1023/A:1021677510649
[5] Cheng Q M. GIS-based multifractal anomaly analysis for prediction of mineralization and mineral deposits[C]//Jeff H. GIS applications in earth sciences. Special Paper of Geological Association of Canada, 2006: 285-296.
[6] Cheng Q M. Non-linear theory and power-law models for information integration and mineral resources quantitative assessments[J]. Mathematical Geosciences, 2008, 40(5): 503-532. doi: 10.1007/s11004-008-9172-6
[7] Corvino A F, Pretorius L E. Uraniferous leucogranites south of Ida Dome, central Damara Belt, Namibia: Morphology, distribution and mineralisation[J]. Journal of African Earth Sciences, 2013, 80: 60-73. doi: 10.1016/j.jafrearsci.2013.01.003
[8] Corvino A F, Pretorius L E. Uraniferous leucogranites south of Ida Dome, central Damara Belt, Namibia: Morphology, distribution and mineralization[J]. Journal of African Earth Sciences, 2013, 80: 60-73. doi: 10.1016/j.jafrearsci.2013.01.003
[9] Coward M P. The tectonic history of the Damaran Belt[C]//Miller R Mc. Evolution of the Damara Orogen of South West Africa. Special Publication of the Geological Society of South Africa, 1983, 11: 409-421.
[10] De Kock G S, Eglington B, Armstrong R, et al. U-Pb and Pb-Pb ages of the Naauwpoort Formation rhyolite, Kawakeup leptite and Okongava diorite: implications for the onset of rifting in the Damara belt, Namibia[J]. Communications - Geological Survey of Namibia, 2000, 12: 81-88.
[11] Goscombe B D, Gray D R. Structure and strain variation at mid-crustal levels in a transpressional orogen: A review of Kaoko Belt structure and the character of West Gondwana amalgamation and dispersal[J]. Gondwana Research, 2008, 13: 45-85. doi: 10.1016/j.gr.2007.07.002
[12] Kröner A, Retief E A, Compston W, et al. Single-age and conventional zircon dating of remobilized basement gneisses in the central Damara belt of Namibia[J]. South African Journal of Geology, 1991, 94: 379-387.
[13] Longridge L, Gibson R L, Kinnaird J A. Dome formation mechanisms in the southwestern Central Zone of the Damara Orogen, Namibia[J]. Trabajos de Geología, Universidad de Oviedo, 2009, 29: 440-444.
[14] Longridge L. Tectonothermal Evolution of the southwestern Central Zone, Damara Belt, Namibia[D]. Ph. D. Thesis, University of the Witwatersrand, South Africa, 2012.
[15] Martin H, Porada H. The intracratonic branch of the Damara Orogen in South West Africa I. Discussion of geodynamic models[J]. Precambrian Research, 1977, 5(4): 311-338. doi: 10.1016/0301-9268(77)90039-0
[16] Miller R M G. The geology of Namibia. Volume 2: Neoproterozoic to Lower Palaeozoic[M]. Geological Survey of Namibia, Windhoek, 2008.
[17] Miller R M G. The Pan-African Damara Orogen of South West Africa/Namibia[C]//Miller R M, The Damara Orogen. Evolution of the Damara Orogen of South West Africa/Namibia. Geological Society of South Africa Special Publication, 1983, 11: 431-515.
[18] Nex P A M, Kinnaird J A, Oliver G J H. Petrology, geochemistry and mineralization ofpost-collisional magmatism in the southern Central Zone, Damaran Orogen, Namibia[J]. Journal of African Earth Sciences, 2001, 33: 481-502. doi: 10.1016/S0899-5362(01)00096-3
[19] Nex P A M. Tectono-metamorphic setting and evolution of granitic sheets in the Goanikontes area, Namibia[D]. Ph. D. Dissertation, National University of Ireland, 1997.
[20] Oliver G J H. Mid-crustal detachment and domes in the Central Zone of the Damara Orogen, Namibia[J]. Journal of African Earth Sciences, 1994, 19: 331-344. doi: 10.1016/0899-5362(94)90018-3
[21] Poli L C, Oliver G J H. Constrictional deformation in the Central Zone of the Damara Orogen, Namibia[J]. Journal of African Earth Sciences, 2001, 33(2): 303-321. doi: 10.1016/S0899-5362(01)80065-8
[22] Porada H. Pan-African rifting and orogenesis in southern and equatorial Africa and eastern Brazil[J]. Precambrian Research, 1989, 44(2): 103-136. doi: 10.1016/0301-9268(89)90078-8
[23] 陈金勇, 范洪海, 王生云, 等. 纳米比亚欢乐谷地区白岗岩型铀矿成矿机理剖析[J]. 高校地质学报, 2017, 23(2): 202-212. doi: 10.16108/j.issn1006-7493.2016222
[24] 陈金勇, 范洪海, 王生云, 等. 纳米比亚欢乐谷地区白岗岩型铀矿成矿物质来源分析[J]. 地质学报, 2016, 90(2): 219-230. doi: 10.3969/j.issn.0001-5717.2016.02.002
[25] 陈金勇. 纳米比亚欢乐谷地区白岗岩型铀矿成矿机理研究[D]. 核工业北京地质研究院博士学位论文, 2014.
[26] 陈军强, 曾威, 王佳营, 等. 全球和我国铀资源供需形势分析[J]. 华北地质, 2021, 44(2): 25-34. https://www.cnki.com.cn/Article/CJFDTOTAL-QHWJ202102004.htm
[27] 成秋明, 陈志军, Ali Khaled. 模糊证据权方法在镇沅(老王寨)地区金矿资源评价中的应用[J]. 地球科学(中国地质大学学报), 2007, (2): 175-184. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200702003.htm
[28] 成秋明, 张生元, 左仁广, 等. 多重分形滤波方法和地球化学信息提取技术研究与进展[J]. 地学前缘, 2009, 16(2): 185-198. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY200902018.htm
[29] 成秋明. 非线性成矿预测理论: 多重分形奇异性-广义自相似性-分形谱系模型与方法[J]. 地球科学, 2006, (3): 337-348. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200603008.htm
[30] 成秋明. 覆盖区矿产综合预测思路与方法[J]. 地球科学(中国地质大学学报), 2012, 37(6): 1109-1125. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201206005.htm
[31] 顾大钊, 范洪海, 孙远强. 纳米比亚白岗岩型铀矿床找矿方法探讨[J]. 矿床地质, 2014, 33(S1): 1105-1106. https://www.cnki.com.cn/Article/CJFDTOTAL-KCDZ2014S1555.htm
[32] 金若时, 滕雪明. 中国北方砂岩型铀矿大规模成矿作用[J]. 华北地质, 2022, 45(1): 42-57. https://www.cnki.com.cn/Article/CJFDTOTAL-QHWJ202201003.htm
[33] 聂江涛, 范洪海, 张杰林, 等. 纳米比亚中西部EPL3602地区构造地质特征及铀矿控矿因素[J]. 铀矿地质, 2013, 29(4): 223-230. https://www.cnki.com.cn/Article/CJFDTOTAL-YKDZ201304004.htm
[34] 宁福俊, 王杰, 任军平, 等. 纳米比亚达马拉构造带演化和成矿研究综述[J]. 地质调查与研究, 2018, 41(2): 113-120. https://www.cnki.com.cn/Article/CJFDTOTAL-QHWJ201802006.htm
[35] 荣建锋, 林泳钊, 王照良. 纳米比亚湖山铀矿床地质概况[J]. 四川地质学报, 2016, 36(1): 101-106. https://www.cnki.com.cn/Article/CJFDTOTAL-SCDB201601022.htm
[36] 万丽, 刘慧, 曾祥健. 普朗斑岩型铜矿床成矿元素多重分形特征及其矿化强度指示[J]. 吉林大学学报(地球科学版), 2021, 51(4): 1054-1063. https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ202104008.htm
[37] 王佳营, 刘行, 薛生升, 等. 奇异性理论在达来庙草原覆盖区找矿弱信息提取中的应用[J]. 华北地质, 2021, 44(2): 14-24. https://www.cnki.com.cn/Article/CJFDTOTAL-QHWJ202102003.htm
[38] 王佳营, 张晓军, 姚春亮, 等. 非线性理论和模糊证据权方法在内蒙古达来庙草原覆盖区钼多金属矿产预测中的应用[J]. 地质调查与研究, 2019, 42(3): 174-184. https://www.cnki.com.cn/Article/CJFDTOTAL-QHWJ201903003.htm
[39] 王生云. 纳米比亚欢乐谷地区花岗岩地球化学特征及成因[D]. 核工业北京地质研究院博士学位论文, 2013.
[40] 张生元, 成秋明, 张素萍, 等. 加权证据权模型和逐步证据权模型及其在个旧锡铜矿产资源预测中的应用[J]. 地球科学(中国地质大学学报), 2009, 34(2): 281-286. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201206014.htm
[41] 赵希刚, 朱西养, 杨永记, 等. 纳米比亚达马拉造山带白岗岩型铀矿成矿规律及找矿思路[J]. 铀矿地质, 2015, 31(4): 445-452. https://www.cnki.com.cn/Article/CJFDTOTAL-YKDZ201504005.htm
[42] 左立波, 任军平, 邱京卫, 等. 纳米比亚罗辛铀矿床地质特征、地球化学特征及成矿模式[J]. 地质找矿论丛, 2015, 30(S1): 137-145. https://www.cnki.com.cn/Article/CJFDTOTAL-DZZK2015S1018.htm
[43] 左立波, 任军平, 王杰, 等. 非洲中南部铀矿床研究现状及资源潜力分析[J]. 地质科技情报, 2017, 36(1): 128-139. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201701016.htm
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