Deep Structure and Mineralization of Zhaxikang Ore-Concentration Area, South Tibet: Evidence from Geophysics
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摘要: 扎西康矿集区是近年藏南发现的最具找矿潜力的多金属矿富集区.但是由于工作条件所限，矿集区开展的地球物理工作程度不高，深部结构和地质信息不明，严重制约了矿集区成矿作用与成矿潜力等重要地质问题研究.为了查明西藏扎西康矿集区深部地质结构，探讨成矿作用的深部机制，在扎西康地区开展了重力、磁法和大地电磁等测量，利用二维小波分解重磁异常和反演的密度、电性结构模型，结合岩石物理性质和地质资料综合分析，认为错那洞片麻岩穹窿在地球物理场上具有3层结构，且下部单元（核部）以淡色花岗岩为主，向北侧延伸到扎西康矿区深部，和矿集区近南北向断裂带、其他次级断裂共同组成了扎西康叠加改造锑铅锌银多金属矿床的控岩、控矿、赋矿系统.处在高低电性块体分区的错那洞变质穹窿形成机制可能与藏南拆离系有关，而错那洞岩体深部延伸、岩浆侵位、就位过程驱动了流体循环，在其他因素参与影响下，共同作用了扎西康矿床的形成.Abstract: The Zhaxikang ore-concentration area (ZOCA) is the most abundant polymetallic ore enrichment area discovered recently in the South Tibet. However, the geophysical work carried out in the ore -concentrated areas is not sufficient due to the limited working conditions, and the deep structure and geological information are not clear, which seriously restricts the understanding of its mineralization and potential of the ore-concentrated areas and other important geological problems. In order to find out the deep geological structure and to discuss the deep mechanism of mineralization, measurements of gravity, magnetic and magnetotelluric were carried out in Zhaxikang area. By using gravity and magnetic anomalies due to two-dimensional wavelet decomposition, density and electrical structure model, and analyses of petrophysical and geological properties, it is indicated that there were 3-layers in geophysics of the Cuonadong gneiss dome. In addition, lower unit (core) mainly consisted of leucogranite, which extends north into the deep of the Zhaxikang Pb-Zn polymetallic deposit. The leucogranite combined with N-S normal faultsystem and other secondary faults made up the ore -forming system of the Zhaxikang overprinting and remobilization ore deposit. The Cuonadong gneiss dome was located in high and low zones of electrical blocks, with formation mechanism likely related with the South Tibet Detachment System (STDS). On the other hand, deep extension of Cuonadong rock and emplacement of leucogranite drove fluid circulation, and the Zhaxikang deposit was formed in combination with influence of other factors.
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Key words:
- Zhaxikang ore-concentration area /
- Cuonadong dome /
- fracture /
- deep structure /
- mineralization /
- geophysics
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图 1 西藏扎西康矿集区地形地质图
据付建刚等(2018)修改
Fig. 1. The topographic and geological map of Zhaxikang ore⁃concentration area, Tibet
图 2 扎西康矿集区重磁场与断裂分布
a.二维小波4阶尺度重力细节; b.二维小波3阶尺度磁力细节
Fig. 2. The distribution of faults and the gravity and magnetic field of Zhaxikang ore⁃concentration area
图 3 错那洞穹窿岩石构造单元物理性质
Fig. 3. Physical properties of rock tectonic units of the Cuonadong dome
图 4 EWM2线综合剖面
a.剖面地形; b.布格重力和磁化极; c.剩余重力反演模型; d.大地电磁反演模型; e.地质剖面
Fig. 4. The comprehensive section of EWM2 line
图 5 扎西康矿集区深部电性结构
a.重力东西向细节异常; b.SNM1线大地电磁反演模型; c.长周期大地电磁反演模型; d.SNM1线频率电性主轴统计
Fig. 5. Deep electrical structure of Zhaxikang ore concentration area
图 6 扎西康矿集区不同深度重磁场特征
a.地形地质图; b.二维小波4阶尺度重力细节; c.二维小波5阶尺度重力细节; d.二维小波4阶尺度磁力细节; e.磁力二维小波5阶尺度细节
Fig. 6. Gravity and magnetic field characteristics at different depths of Zhaxikang ore concentration area
图 7 扎西康矿集区成矿作用解释示意图
a.扎西康矿集区地形地质图; b.磁异常小波变换4阶细节; c.密度体三维反演(中酸性岩体); d.磁异常小波变换5阶细节; SNM1⁃ SNM1'.大地电磁电阻率反演断面图(红色等值线代表高电阻率)
Fig. 7. Schematic diagram of mineralization of Zhaxikang ore concentration area
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Chen, Z., Liu, Y., Hodges, K. V., et al., 1990. The Kangmar Dome:A Metamorphic Core Complex in Southern Xi-zang (Tibet).Science, 250(4987):1552-1556. https://doi.org/10.1126/science.250.4987.1552 Fu, J.G., Li, G.M., Wang, G.H., et al., 2017.First Field Identification of the Cuonadong Dome in Southern Tibet:Im-plications for EW Extension of the North Himalayan Gneiss Dome. International Journal of Earth Sciences, 106(5):1581-1596. https://doi.org/10.1007/s00531-016-1368-2 Fu, J.G., Li, G.M., Wang, G.H., et al., 2018.Timing of E-W Extension Deformation in North Himalaya:Evidences from Ar-Ar Age in the Cuonadong Dome, South Tibet.Earth Science, 43(8):2638-2650(in Chinese with Eng-lish abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DQKX201808008.htm Gao, L.E., Zeng, L.S., Shi, W.G., et al., 2012.Two Types of Garnets in the Cenozoic Granites from the Himayalan Orogenic Belt:Geochemical Characteristics and Implica-tions for Crustal Anatexis. Acta Petrologica Sinica, 28(9):2963-2980 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-YSXB201209024.htm Hou, Z.Z., Yang, W.C., Liu, J.Q., 1998.Multiscale Inversion of the Density Contrast within the Crust of China. Chi-nese Journal of Geophysics, 41(5):642-651(in Chinese with English abstract). http://cn.bing.com/academic/profile?id=484218c51afc9705f6f0034ba050c02d&encoded=0&v=paper_preview&mkt=zh-cn Jiao, Y.J., Liang, S.X., Guo, J., et al., 2015.Comparative Re-search on the Combinational Test of Geophysical Meth-ods in the Zhaxikang Lead-Zinc Ore Concentration Area, Tibet.Geophysical and Geochemical Exploration, 39(2):245-252(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-WTYH201502006.htm Lee, J., Hacker, B., Wang, Y., 2004.Evolution of North Hima-layan Gneiss Domes:Structural and Metamorphic Stud-ies in Mabja Dome, Southern Tibet.Journal of Structur-al Geology, 26(12):2297-2316. https://doi.org/10.1016/j.jsg.2004.02.013 Li, H. Y., Yang, C. B., Wu, Y. G., et al., 2014. Application of Wavelet Transform for De-Noising and Potential Field Separation in Gravity and Magnetic Data Processing.Global Geology, 33(1):200-208(in Chinese with Eng-lish abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=sjdz201401021 Li, Y. G., Oldenburg, D. W., 1998.3-D Inversion of Gravity Data. Geophysics, 63(1):109-119. https://doi.org/10.1190/1.1444302 Liang, S.X., 2018.A Self-Constrained 3D Inversion and Effi-cient Solution of Gravity Data Based on Cross-Correla-tion Coefficient. Journal of Jilin University (Earth Sci-ence Edition), 48(5):1473-1482(in Chinese with Eng-lish abstract). Liang, S.X., Rouzi, W.S.A.L., Liao, G.Z., et al., 2014.Com-parison and Analysis of Two-Dimensional Linear Algo-rithm Inversion for Magnetotelluric.Progress in Geophys-ics, 29(6):2702-2707(in Chinese with English abstract). Liang, W., Hou, Z.Q., Yang, Z.S., et al., 2013.Remobilization and Overprinting in the Zhaxikang Pb-Zn-Ag-Sb Polymetal Ore Deposit, Southern Tibet:Implications for Its Metallogenesis. Acta Petrologica Sinica, 29(11):3828-3842(in Chinese with English abstract). Liang, W., Yang, Z.S., Zheng, Y.C., 2015.The Zhaxikang Pb-Zn Polymetallic Deposit:Ar-Ar Age of Sericite and Its Metallogenic Significance.Acta Geologica Sinica, 89(3):560-568(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DZXE201503010.htm Liang, W., Zheng, Y. C., Yang, Z. S., et al., 2014. Multiphase and Polystage Metallogenic Process of the Zhaxikang Large-Size Pb-Zn-Ag-Sb Polymetallic Deposit in South-ern Tibet and Its Implications.Acta Petrologica et Miner-alogica, 33(1):64-78(in Chinese with English abstract). Liu, X.J., Wang, J.L., Chen, B., et al., 2007.Discussion on Fo-cus Inversion Algorithm of 2-D MT Data.Oil Geophysi-cal Prospecting, 42(3):338-342(in Chinese with English abstract). Portniaguine, O., Zhdanov, M.S., 1999.Focusing Geophysical Inversion Images.Geophysics, 64(3):874-887. doi: 10.1190/1.1444596 Qing, C.S., Ding, J., Zhou, Q., et al., 2014.Primary Halo Char-acteristics of the Zhaxikang Lead-Zinc Polymetallic De-posit, Tibet. Acta Petrologica et Mineralogica, 33(6):1113-1126(in Chinese with English abstract). Rodi, W., MacKie, R.L., 2001.Nonlinear Conjugate Gradients Algorithm for 2-D Magnetotelluric Inversion. Geophys-ics, 66(1):174-187. doi: 10.1190/1.1444893 Smith, J.T., Booker, J.R., 1996.Rapid Inversion of Two-and Three-Dimensional Magnetotelluric Data. Journal of Geophysical Research:Solid Earth and Planets, 96(B3):3905-3922. http://cn.bing.com/academic/profile?id=3a5cdc70f7ca165655216015b4da5ce3&encoded=0&v=paper_preview&mkt=zh-cn Wei, W.B., Jin, S., Ye, G.F., et al., 2009.Conductivity Struc-ture and Rheological Property of Lithosphere in South-ern Tibet Inferred from Super-Broadband Magnetotellu-ric Sounding.Science in China (Series D), 39(11):1591-1606(in Chinese). doi: 10.1007/s11430-010-0001-7 Wu, F.Y., Liu, Z.C., Liu, X.C., et al., 2015.Himalayan Leuco-granite:Petrogenesis and Implications to Orogenesis and Plateau Uplift. Acta Petrologica Sinica, 31(1):1-36(in Chinese with English abstract). https://www.researchgate.net/publication/279331756_Himalayan_leucogranite_Petrogenesis_and_implications_to_orogenesis_and_plateau_uplift Yao, C. L., Hao, T. Y., Guan, Z. N., et al., 2003. High-Speed Computation and Efficient Storage in 3-D Gravity and Magnetic Inversion Based on Genetic Algorithms. Chi-nese Journal of Geophysics, 46(2):252-258(in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqwlxb200302020 Zeng, L. S., Liu, J., Gao, L. E., et al., 2009. Early Oligocene Anatexis in the YardoiGneiss Dome, Southern Tibet and Geological Implications.Chinese Science Bulletin, 54(3):373-381(in Chinese). http://cn.bing.com/academic/profile?id=efeef93ba005f445e64960607e226af0&encoded=0&v=paper_preview&mkt=zh-cn Zhang, J. J., 2007. A Review on the Extensional Structures in the Northern Himalaya and Southern Tibet. Geological Bulletin of China, 26(6):639-649(in Chinese with Eng-lish abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=zgqydz200706003 Zhang, L. K., Zhang, Z., Li, G. M., et al., 2018. Rock Assem-blage, Structural Characteristics and Genesis Mechanism of the Cuonadong Dome, Tethys Himalaya. Earth Sci-ence, 43(8):2664-2683(in Chinese with English ab-stract). Zhu, D., Liu, T. Y., Li, H. W., 2018. Separation of Potential Field Based on Singular Spectrum Analysis. Chinese Journal of Geophysics, 61(9):3800-3811(in Chinese with English abstract). http://d.old.wanfangdata.com.cn/Periodical/dqwlxb201809028 付建刚, 李光明, 王根厚, 等, 2018.北喜马拉雅E-W向伸展变形时限:来自藏南错那洞穹隆Ar-Ar年代学证据.地球科学, 43(8):2638-2650. http://www.earth-science.net/WebPage/Article.aspx?id=3902 高利娥, 曾令森, 石卫刚, 等, 2012.喜马拉雅造山带新生代花岗岩中两类石榴石的地球化学特征及其在地壳深熔作用中的意义.岩石学报, 28(9):2963-2980. http://d.old.wanfangdata.com.cn/Conference/8276183 侯遵泽, 杨文采, 刘家琦, 1998.中国大陆地壳密度差异多尺度反演.地球物理学报.地球物理学报.41(5):642-651. doi: 10.3321/j.issn:0001-5733.1998.05.007 焦彦杰, 梁生贤, 郭靖, 等, 2015.西藏扎西康铅锌矿集区的物探方法组合试验.物探与化探, 39(2):245-252. http://d.old.wanfangdata.com.cn/Periodical/wtyht201502006 李红雨, 杨长保, 吴燕冈, 等, 2014.小波变换在位场资料去噪和位场分离中的应用.世界地质, 33(1):200-208. doi: 10.3969/j.issn.1004-5589.2014.01.021 梁生贤, 2018.互相关系数自约束的重力三维反演与高效求解.吉林大学学报(自然科学版), 48(5):1473-1482. http://d.old.wanfangdata.com.cn/Periodical/cckjdxxb201805016 梁生贤, 吾守艾力·肉孜, 廖国忠, 等, 2014.大地电磁线性反演算法比较.地球物理学进展, 29(6):2702-2707. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ201406035.htm 梁维, 侯增谦, 杨竹森, 等, 2013.藏南扎西康大型铅锌银锑多金属矿床叠加改造成矿作用初探.岩石学报, 29(11):3828-3842. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201311015 梁维, 杨竹森, 郑远川, 2015.藏南扎西康铅锌多金属矿绢云母Ar-Ar年龄及其成矿意义.地质学报, 89(3):560-568. http://d.old.wanfangdata.com.cn/Periodical/dizhixb201503009 梁维, 郑远川, 杨竹森, 等, 2014.藏南扎西康铅锌银锑多金属矿多期多阶段成矿特征及其指示意义.岩石矿物学杂志, 33(1):64-78. doi: 10.3969/j.issn.1000-6524.2014.01.005 刘小军, 王家林, 陈冰, 等, 2007.二维大地电磁数据的聚焦反演算法探讨.石油地球物理勘探, 42(3):338-342. doi: 10.3321/j.issn:1000-7210.2007.03.020 卿成实, 丁俊, 周清, 等, 2014.西藏扎西康铅锌多金属矿床原生晕特征.岩石矿物学杂志, 33(6):1113-1126. doi: 10.3969/j.issn.1000-6524.2014.06.009 魏文博, 金胜, 叶高峰, 等, 2009.藏南岩石圈导电性结构与流变性-超宽频带大地电磁测深研究结果.中国科学(D辑), 39(11):1591-1606. http://www.cqvip.com/Main/Detail.aspx?id=32218085 吴福元, 刘志超, 刘小驰, 等, 2015.喜马拉雅淡色花岗岩.岩石学报, 31(1):1-36. http://d.old.wanfangdata.com.cn/Periodical/dqkx200503003 姚长利, 郝天珧, 管志宁, 等, 2003.重磁遗传算法三维反演中高速计算及有效存储方法技术.地球物理学报.46(2):252-258. doi: 10.3321/j.issn:0001-5733.2003.02.020 曾令森, 刘静, 高利娥, 等, 2009.藏南也拉香波穹隆早渐新世地壳深熔作用及其地质意义.科学通报, 54(3):373-381. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=kxtb200903018 张进江, 2007.北喜马拉雅及藏南伸展构造综述.地质通报.26(6):639-649. doi: 10.3969/j.issn.1671-2552.2007.06.003 张林奎, 张志, 李光明, 等, 2018.特提斯喜马拉雅错那洞穹隆的岩石组合、构造特征与成因.地球科学, 43(8):2664-2683. http://www.earth-science.net/WebPage/Article.aspx?id=3904 朱丹, 刘天佑, 李宏伟, 2018.基于奇异谱分析的重磁位场分离方法.地球物理学报, 61(9):3800-3811. http://d.old.wanfangdata.com.cn/Periodical/dqwlxb201809028 -
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