Singularity Modeling of Geo-Anomalies and Recognition of Anomalies Caused by Buried Sources
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摘要: 以个旧锡多金属矿床为例,研究了致矿地质异常的非线性特征.从异常地质事件和成矿作用的奇异性出发,定量分析了地质异常的奇异性、不连续性、非平稳性、混沌性、自相似性、临界性等非线性特征.在此基础上,详细介绍了局部奇异性分析原理和方法,论述了奇异性指数对隐伏源异常的识别能力.结果表明,奇异性分析方法在个旧地区水系沉积物地球化学数据处理和隐伏源地球化学异常识别和圈定应用中是有效的.分析结果一定程度上消除了隐伏源深度的影响,所圈定的局部地球化学异常不仅在个旧东区较好地对应了已发现的大型锡矿床的分布,而且在其他低缓地球化学异常区也圈定了多处局部异常,为进一步开展锡矿勘查提供了重要靶区.奇异性理论和方法有望为深部矿产预测、隐伏矿预测、覆盖区矿产预测等特殊环境开展矿产预测提供了新的实用性理论和方法技术.Abstract: This paper investigates the nonlinear properties of geo-anomalies related to mineralization. It was demonstrated that geochemical anomalies in stream sediments in Gejiu mineral district caused by Sn mineralization can be modeled by fractal and multifractal models and they depict singularity, discontinuity, chaoticality, and indifferentiality. It was also shown that the singularity calculated from 2D geochemical landscape can reflect the causes of buried sources. The concepts and methods were validated using the concentration values of trace elements Sn, Cu, As, Pb, Zn and Cd in stream sediments. The results obtained using windows-based local singularity analysis method not only provide anomalies in general agreement with the locations of known mineral deposits in the eastern Gejiu district but also new anomalies delineated in the other areas of Gejiu that provide potential target areas for further mineral exploration for undiscovered Sn mineral deposits. It is anticipated that the singularity analysis method introduced in the paper will become a new powerful tool applicable for quantitative prediction of buried mineral deposits in covered terrain.
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图 1 个旧地区简化地质图
紫红色多边形代表个旧岩体;黄色多边形代表个旧组碳酸盐地层;白色区域表示其他地层;黑色实线代表断裂构造;圆点代表锡矿床;箭头线A-A'表示剖面线(图 2c)的位置
Fig. 1. Simplified geology of the Gejiu mineral district
图 3 (a) 水系沉积物Sn含量图;(b)密度-面积关系图, 四段直线段由最小二乘法拟合
a图中黑三角形表示锡矿床,等值线表示由图b中密度-面积关系确定的异常区间;白色等值线表示Sn>344×10-6(Ⅰ),黑粗等值线6×10-6<Sn≤344×10-6(Ⅱ),黑细等值线2×10-6<Sn≤6×10-6(Ⅲ)
Fig. 3. (a) Distribution of log-transformed values (10-6) of Sn in stream sediment samples.; (b) C-A (concentration-area) plot showing the cumulative area (number of cells of 4 km2) versus the tin concentration value; the base of logarithms is e
图 4 云南个旧东区某地水系沉积物As元素密度与面积关系(Cheng and Zhao, 2011)
实线代表采用最小二乘法拟合的幂率模型
Fig. 4. Relationship between the concentration density values (10-6/km2) of As and square windows with various window sizes
图 5 (a) 由主成分分析方法所计算的地球化学组合元素(Sn、Cu、As、Pb、Zn and Cd)分布;(b) 采用局部奇异性分析方法所计算的奇异性指数值分布
透明的多边形表示个旧岩体分布范围;白色的圆圈代表锡矿床;黑色线条代表断裂构造
Fig. 5. (a) Scoring map of the first principle component showing the spatial distribution of multiple elements of Sn, Cu, As, Pb, Zn and Cd; (b) Singularity obtained from the anomalies in Fig. 5a, with a positive value of 5 added so that the map has positive values. Singularity was calculated with square windows sized within 26 km
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[1] Cheng, Q.M., 1999. Multifractality and spatial statistics. Computers & Geosciences, 25(10): 949-961. http://www.sciencedirect.com/science/article/pii/S0098300499000606 [2] Cheng, Q.M., 2007a. Mapping singularities with stream sediment geochemical data for prediction of undiscovered mineral deposits in Gejiu, Yunnan Province, China. Ore Geology Reviews, 32(1-2): 314-324. doi: 10.1016/j.oregeorev.2006.10.002 [3] Cheng, Q.M., 2007b. Multifractal imaging filtering and decomposition methods in space, fourier frequency, and eigen domains. Nonlinear Processes in Geophysics, 14(3): 293-303. doi: 10.5194/npg-14-293-2007 [4] Cheng, Q.M., 2007c. Singular mineralization processes and mineral resources quantitative prediction: new theories and methods. Earth Science Frontiers, 14(5): 42-53. [5] Cheng, Q.M., 2007d. GIS based fractal/multifractal anomaly analysis for modeling and prediction of mineralization and mineral deposits. In: Harris, J., Wright, D., eds., GIS for geosciences. Geological Association of Canada, 285-296. [6] Cheng, Q.M., Agterberg, F.P., 2009. Singularity analysis of ore-mineral and toxic trace elements in stream sediments. Computers & Geosciences, 35(2): 234-244. http://www.sciencedirect.com/science/article/pii/S0098300408002203 [7] Cheng, Q.M., Agterberg, F.P., Ballantyne, S.B., 1994. The separation of geochemical anomalies from background by fractal methods. J. Geochemical Exploration, 51(2): 109-130. doi: 10.1016/0375-6742(94)90013-2 [8] Cheng, Q.M., Xu, Y., Grunsky, E., 1999. Integrated spatial and spectral analysis for geochemical anomaly separation. In: Lippard, S.J., Naess, A., Sinding-Larsen, R., eds., Proceedings of the Firth Annual Conference of the International Association for Mathematical Geology, Trondheim, Norway 6-11th August, 1, 87-92. [9] Cheng, Q.M., Zhao, P.D., 2011. Singularity theories and methods for characterizing mineralization processes and mapping geo-anomalies for mineral deposit prediction. Geoscience Frontiers, doi: 10.1016/j.gsf.2010.12.003 [10] Cheng, Q.M., Zhao, P.D., Chen, J.G., et al., 2009a. Application of singularity theory in prediction of tin and copper mineral deposits in Gejiu district, Yunnan, China: weak information extraction and mixing information decomposition. Earth Science—Journal of China University of Geosciences, 34(2): 232-242 (in Chinese with English abstract). doi: 10.3799/dqkx.2009.021 [11] Cheng, Q.M., Zhao. P.D., Zhang, S.Y., et al., 2009b. Application of singularity theory in prediction of tin and copper mineral deposits in Gejiu district, Yunnan, China: information integration and delineation of mineral exploration targets. Earth Science—Journal of China University of Geosciences, 34(2): 243-252 (in Chinese with English abstract). doi: 10.3799/dqkx.2009.022 [12] Cheng, Y.B., Mao, J.W., Xie, G.Q., et al., 2008. Petrogenesis of the Laochang-Kafang granite in the Gejiu area, Yunnan Province: constraints from geochemistry and zircon U-Pb dating. Acta Geologica Sinica, 82(11): 1478-1493 (in Chinese with English abstract). [13] Editorial Board, 2010. Hand book of advanced technologies for geological (deep) mineral exploration (Vol. 4). Geological Publishing House, Beijing (in Chinese). [14] Journel, A.G., Huijbregts, C.J., 1978. Mining Geostatistics. Academic Press, London, 600. [15] Qing, D.X., Tan, S.C., Fan, Z.G., 2004. Geotectonic evolution and tin-polymetallic metallogenesis in Gejiu-Dachang area. Journal of Mineralogy, 24(2): 118-123 (in Chinese with English abstract). http://www.cqvip.com/Main/Detail.aspx?id=9972391 [16] Tan, S.C., Qing, D.X., Chen, A.B., et al., 2004. Regional crust evolution and metallogenesis of Gejiu tin deposit—a discussion. Journal of Mineralogy, 24(2): 157-163 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-KWXB200402011.htm [17] Xia, Q.L., Zhang, S.T., Chen, S.Y., et al., 2007. The key problems for deep mineral potential assessment in Gejiu tin deposit, Yunnan, China. Acta Mineralogica Sinica, 27(Suppl. ): 530-531 (in Chinese with English abstract). [18] Xiong, G.C., Shi, S.T., 1994. Physico-geologic model of the Gejiu tin district and its application. Geological Review, 40(1): 19-27 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DZLP199401002.htm [19] Xu, Q.D., Xia, Q.L., Cheng, Q.M., 2009. Tectono-magmatic evolution related to metallogenic system in the Gejiu ore area, southeastern Yunnan of China. Earth Science—Journal of China University of Geosciences, 34(2): 307-313 (in Chinese with English abstract). doi: 10.3799/dqkx.2009.032 [20] Zhao, P.D., 2001. Three component mineral resource quantitative prediction and assessment: quantitative mineral resource prediction theory and practice. Earth Science—Journal of China University of Geosciences, 27(5): 139-148 (in Chinese with English abstract). [21] Zhao, P.D., 2007. Quantitative mineral prediction and deep mineral exploration. Earth Science Frontiers, 14(5): 1-10 (in Chinese with English abstract). http://www.researchgate.net/publication/285501491_Quantitative_mineral_prediction_and_deep_mineral_exploration [22] Zhuang, Y.Q., Wang, R.Z., Yang, S.P., et al., 1996. Sn and Cu polymetallic mineral deposits in Gejiu. Seismology Press, Beijing, 124 (in Chinese). [23] 编委会, 2010. 现代地质(深部)找矿新技术标准手册(第4卷). 北京: 地质出版社. [24] 成秋明, 赵鹏大, 陈建国, 等, 2009a. 奇异性理论在个旧锡铜矿产资源预测中的应用: 成矿弱信息提取和复合信息分解. 地球科学——中国地质大学学报, 34(2): 232-242. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200902001.htm [25] 成秋明, 赵鹏大, 张生元, 等, 2009b. 奇异性理论在个旧锡铜矿产资源预测中的应用: 综合信息集成与靶区圈定. 地球科学——中国地质大学学报, 34(2): 243-252. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200902002.htm [26] 程彦博, 毛景文, 谢桂青, 等, 2008. 云南个旧老厂-卡房花岗岩体成因: 锆石U-Pb年代学和岩石地球化学约束. 地质学报, 82(11): 1478-1493. doi: 10.3321/j.issn:0001-5717.2008.11.003 [27] 秦德先, 谈树成, 范柱国, 等, 2004. 个旧-大厂地区地质构造演化及锡多金属成矿. 矿物学报, 24(2): 118-123. https://www.cnki.com.cn/Article/CJFDTOTAL-KWXB200402004.htm [28] 谈树成, 秦德先, 陈爱兵, 等, 2004. 个旧锡矿区域地壳演化与成矿探讨. 矿物学报, 24(2): 157-163. doi: 10.3321/j.issn:1000-4734.2004.02.011 [29] 夏庆霖, 张寿庭, 陈守余, 等, 2007. 云南个旧锡矿深部资源潜力评价的几个关键问题. 矿物学报, 27(增刊): 530-531. [30] 熊光楚, 石盛滕, 1994. 个旧锡矿区物理-地质模型及应用效果. 地质论评, 40(1): 19-27. doi: 10.3321/j.issn:0371-5736.1994.01.003 [31] 徐启东, 夏庆霖, 成秋明, 2009. 云南个旧矿集区区域构造-岩浆演化与锡铜多金属成矿系统. 地球科学——中国地质大学学报, 34(2): 307-313. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200902013.htm [32] 赵鹏大, 2001. 三联式矿产资源定量预测与评价: 数值化矿产预测理论与实践. 地球科学——中国地质大学学报, 27(5): 139-148. [33] 赵鹏大, 2007. 成矿定量预测与深部找矿. 地学前缘, 14(5): 1-10. doi: 10.3321/j.issn:1005-2321.2007.05.001 [34] 庄永秋, 王任重, 杨树培, 等, 1996. 云南个旧锡铜多金属矿床. 北京: 地震出版社, 124.