CSAMT方法在仓上金矿外围及深部找矿中的应用
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摘要
仓上金矿位于三山岛—仓上断裂西南部,西邻渤海湾,是我国大型露天金矿之一。至2005年闭坑后,在矿山外围及深部找矿一直未取得新进展。为加大勘探深度,探查矿区外围和深部断裂及岩体的空间展布情况,寻找深部金矿资源,采用CSAMT331号地质剖面进行了综合对比分析,结果显示F1推断断层与三山岛—仓上断裂相吻合,提出验证钻孔1个。经钻探工程验证见金矿体,取得了较好的应用找矿效果,为下一步开展地质找矿提供了有价值的地球物理信息依据。
There are abundant gold resources in Jiaodong area,which are mainly controlled by SanshandaoCangshang fault,Jiaojia fault and Zhaoping fault.Three major gold metallogenic belts were formed in the area,where several large and super-large gold deposits have been found. Jiaodong area has provided a large amount of gold reserves,and it’s an significant gold concentration area and gold industrial base in China. The main research area in this paper is Cangshang gold deposit,which located in southwest of Sanshandao-Cangshang fault that adjacent to the Bohai Bay.It is one of the large open-air gold deposit in China. Since Cangshang gold deposit closure in 2005,Shandong Gold Group,many geological exploration agencies and scientific research institutes have conducted a lot of prospecting work around the mine,but no new progress has been made in prospecting.In order to find out the spatial distribution of the fault and rock mass in the depth and periphery of the mining area,and search for deep gold resources,geophysical exploration method was used to conduct deep exploration in the area,and the conventional electrical and magnetic exploration was compared with CSAMT(Controlled Source Audio-Frequency Magnetotellurics).The conventional electric and magnetic exploration is difficult to meet the needs of exploration because the the depth of conventional electric and magnetic exploration is relatively shallow,and the results are reflected on the plane.CSAMT was choose to conduct deep profile exploration in the area. Field construction was carried out in the northern part of the mining area,and two CSAMT sounding sections were arranged along the vertical direction of the Cangshang fault,numbered L4000 and L4300. The length of L4000 section was 1 440 m,and L4300 section was 1 160 m,line distance was 300 m,point distance was 40 m and azimuth angle was 120°.The emission dipole sources AB were arranged in parallel lines in the northeast.The dipole distance of AB was 1.2 km,the receiving dipole distance of MN was 40 m,the receiving and transmitting distance was 5 km,and the detection depth was 1 km. The frequency acquisition range was 1～7 680 Hz,with a total of 40 frequency points. In order to ensure the quality of data acquisition and reduce human interference,a 21 KAV high-power generator was used for power supply.The low frequency current (1 Hz) was not less than 18 A,the high frequency current (7 680 Hz) was not less than 5 A,and the current at intermediate frequency was decreasing. Data processing and inversion were carried out by using software CMTPro and CSAMT-SW V3.0. The data processing included data preprocessing,trip point removal,near-field source correction,static correction and two-dimensional joint inversion.Finally,a map was drawn and the inversion results were compared and analyzed comprehensively with previous geophysical prospecting data and geological profile 331. The inversion results of CSAMT showed that the resistivity characteristics of strata and rock mass were basically consistent with those of conventional electrical methods,and the inferred fault F1 was consistent with Sanshandao-Cangshang fault,indicating that this method has good application effect in this area. In order to verify the low-resistance abnormal zone(F1 fault),a verification borehole was deployed at the corresponding surface location. Through the verification of drilling project,fault mud,weak sericitization granite cataclastic rocks,cataclastic granite rocks and sericitization granite cataclastic rocks were found at the depth of 776.25 ～829.70 m,corresponding to the low-resistance abnormal zone(F1 fault).Gold orebodies were found in sericitization granitic cataclastic rocks,the highest grade is 7.30×10-6 after assay. In summary,good prospecting results are achieved while applying to the field geological exploration work,and will provide valuable geophysical information basis for further geological prospecting.
There are abundant gold resources in Jiaodong area,which are mainly controlled by SanshandaoCangshang fault,Jiaojia fault and Zhaoping fault.Three major gold metallogenic belts were formed in the area,where several large and super-large gold deposits have been found. Jiaodong area has provided a large amount of gold reserves,and it’s an significant gold concentration area and gold industrial base in China. The main research area in this paper is Cangshang gold deposit,which located in southwest of Sanshandao-Cangshang fault that adjacent to the Bohai Bay.It is one of the large open-air gold deposit in China. Since Cangshang gold deposit closure in 2005,Shandong Gold Group,many geological exploration agencies and scientific research institutes have conducted a lot of prospecting work around the mine,but no new progress has been made in prospecting.In order to find out the spatial distribution of the fault and rock mass in the depth and periphery of the mining area,and search for deep gold resources,geophysical exploration method was used to conduct deep exploration in the area,and the conventional electrical and magnetic exploration was compared with CSAMT(Controlled Source Audio-Frequency Magnetotellurics).The conventional electric and magnetic exploration is difficult to meet the needs of exploration because the the depth of conventional electric and magnetic exploration is relatively shallow,and the results are reflected on the plane.CSAMT was choose to conduct deep profile exploration in the area. Field construction was carried out in the northern part of the mining area,and two CSAMT sounding sections were arranged along the vertical direction of the Cangshang fault,numbered L4000 and L4300. The length of L4000 section was 1 440 m,and L4300 section was 1 160 m,line distance was 300 m,point distance was 40 m and azimuth angle was 120°.The emission dipole sources AB were arranged in parallel lines in the northeast.The dipole distance of AB was 1.2 km,the receiving dipole distance of MN was 40 m,the receiving and transmitting distance was 5 km,and the detection depth was 1 km. The frequency acquisition range was 1～7 680 Hz,with a total of 40 frequency points. In order to ensure the quality of data acquisition and reduce human interference,a 21 KAV high-power generator was used for power supply.The low frequency current (1 Hz) was not less than 18 A,the high frequency current (7 680 Hz) was not less than 5 A,and the current at intermediate frequency was decreasing. Data processing and inversion were carried out by using software CMTPro and CSAMT-SW V3.0. The data processing included data preprocessing,trip point removal,near-field source correction,static correction and two-dimensional joint inversion.Finally,a map was drawn and the inversion results were compared and analyzed comprehensively with previous geophysical prospecting data and geological profile 331. The inversion results of CSAMT showed that the resistivity characteristics of strata and rock mass were basically consistent with those of conventional electrical methods,and the inferred fault F1 was consistent with Sanshandao-Cangshang fault,indicating that this method has good application effect in this area. In order to verify the low-resistance abnormal zone(F1 fault),a verification borehole was deployed at the corresponding surface location. Through the verification of drilling project,fault mud,weak sericitization granite cataclastic rocks,cataclastic granite rocks and sericitization granite cataclastic rocks were found at the depth of 776.25 ～829.70 m,corresponding to the low-resistance abnormal zone(F1 fault).Gold orebodies were found in sericitization granitic cataclastic rocks,the highest grade is 7.30×10-6 after assay. In summary,good prospecting results are achieved while applying to the field geological exploration work,and will provide valuable geophysical information basis for further geological prospecting.
引文
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[6]李冰,晁代超,魏明君,等.电磁测深技术在深部铁矿探测中的应用研究——以河南舞阳铁矿区为例[J].中国地质,2013,40(5):1644-1654.Li Bing,Chao Daichao,Wei Mingjun,et al.The application of electromagnetic sounding method to deep iron ore exploration:A case study of the Wuyang iron mining area of Henan[J].Geology in China,2013,40(5):1644-1654.
[7]王振军,李伟明,原波.山东三山岛-新立-仓上金矿床构造叠加晕特征浅析[J].黄金科学技术,2013,21(4):48-53.Wang Zhenjun,Li Weiming,Yuan Bo.Features of structural superimposed halos in Sanshandao-Xinli-Cangshang gold deposits,Shandong Province[J].Gold Science and Technology,2013,21(4):48-53.
[8]宋明春,张军进,张丕建,等.胶东三山岛北部海域超大型金矿床的发现及其构造-岩浆背景[J].地质学报,2015,89(2):365-383.Song Mingchun,Zhang Junjin,Zhang Pijian,et al.Discovery and tectonic-magmatic background of superlarge gold deposit in offshore of northern Sanshandao,Shandong Peninsula,China[J].Acta Geologica Sinica,2015,89(2):365-383.
[9]王友芳,孙世福,张荣敏,等.山东省莱州市仓上金矿北部含金破碎蚀变带物探普查成果报告[R].济南:山东省物化探勘查院,2003.Wang Youfang,Sun Shifu,Zhang Rongmin,et al.Results of geophysical survey of gold bearing fragmentation alteration zone in northern Cangshang gold deposit,Laizhou,Shandong[R].Jinan:Shandong Institute of Geophysical and Geochemical Exploration,2003.
[10]董坤,薄杨.V8工作站CSAMT勘探成果三维可视化研究[J].赤峰学院学报(自然科学版),2013,29(5):44-46.Dong Kun,Bo Yang.Research on 3D visualization of CSAMT exploration results of V8 workstation[J].Journal of Chifeng University(Natural Science Edition),2013,29(5):44-46.
[11]王若,王妙月,底青云,等.CSAMT三维单分量有限元正演[J].地球物理学进展,2014,29(2):839-845.Wang Ruo,Wang Miaoyue,Di Qingyun,et al.3DICCSAMT modeling using finite element method[J].Progress in Geophysics,2014,29(2):839-845.
[12]段文旭,肖宏跃,刘垒,等.CSAMT方法在铁矿勘探中的应用[J].物探化探计算技术,2014,36(2):190-193.Duan Wenxu,Xiao Hongyue,Liu Lei,et al.Application of the CSAMT in iron mine exploration[J].Computing Techniques for Geophysical and Geochemical Exploration,2014,36(2):190-193.
[13]底青云,王妙月,石昆法,等.高分辨V6系统在矿山顶板涌水隐患中的应用研究[J].地球物理学报,2002,45(5):744-748.Di Qingyun,Wang Miaoyue,Shi Kunfa,et al.An applied study on prevention of water bursting disaster in mines with the high resolution V6 system[J].Chinese Journal of Geophysics,2002,45(5):744-748.
[14]夏训银,王身龙,王洪生,等.CSAMT方法在铁路隧道勘探中的应用[J].勘察科学技术,2006(4):61-64.Xia Xunyin,Wang Shenlong,Wang Hongsheng,et al.Application of CSAMT to exploration of railway tunnel[J].Site Investigation Science and Technology,2006(4):61-64.
[15]董晴晴,冯欣欣.AMT方法在深部断裂构造识别中的应用——以南吕-欣木金矿区为例[J].山东国土资源,2016,32(10):48-51.Dong Qingqing,Feng Xinxin.Application of AMT technology in identifying deep fault structures——setting Nanlü-Xinmu gold mine as an example[J].Shandong Land and Resources,2016,32(10):48-51.
[16]韦乖强,赵慧,赵秀玲,等.CSAMT在隐伏地质构造勘查中的三维可视化应用[J].山东国土资源,2015,31(4):56-58.Wei Guaiqiang,Zhao Hui,Zhao Xiuling,et al.Application of three-dimensional visualization of CSAMT in exploring concealed geological structures[J].Shandong Land and Resources,2015,31(4):56-58.
[17]于昌明.CSAMT方法在寻找隐伏金矿中的应用[J].地球物理学报,1998,41(1):133-138.Yu Changming.The application of CSAMT method in looking for hidden gold mine[J].Acta Geophysica Sinica,1998,41(1):133-138.
[2]喻春,陈永凌,李建忠,等.可控源音频大地电磁法在高楼山金矿深部找矿中的应用[J].黄金科学技术,2016,24(1):59-63.Yu Chun,Chen Yongling,Li Jianzhong,et al.Application of CSAMT to deep mine prospecting in the Gaoloushan gold mine[J].Gold Science and Technology,2016,24(1):59-63.
[3]杨炳南,周琦,杜远生,等.音频大地电磁法对深部隐伏构造的识别与应用:以贵州省松桃县李家湾锰矿为例[J].地质科技情报,2015,34(6):26-32.Yang Bingnan,Zhou Qi,Du Yuansheng,et al.Identification and application of audio magnetotellurics to the deep buried structure:A case study of Lijiawan manganese deposit at Songtao County in Guizhou Province[J].Geological Science and Technology Information,2015,34(6):26-32.
[4]郑振云,轩慎英,郑洁,等.可控源音频大地电磁测深法在甘肃寨上金矿区的找矿应用研究[J].黄金科学技术,2017,25(2):7-13.Zheng Zhenyun,Xuan Shenying,Zheng Jie,et al.Application of controlled source audio magnetotelluric sounding method in prospecting of Zhaishang gold mine,Gansu Province[J].Gold Science and Technology,2017,25(2):7-13.
[5]龚飞,底青云,王光杰,等.CSAMT方法对虎跳峡龙蟠右岸变形体的反应特征[J].工程地质学报,2005,13(4):542-545.Gong Fei,Di Qingyun,Wang Guangjie,et al.CSAMTmethod for exploration of deformation bodies in Longpan area[J].Journal of Engineering Geology,2005,13(4):542-545.
[6]李冰,晁代超,魏明君,等.电磁测深技术在深部铁矿探测中的应用研究——以河南舞阳铁矿区为例[J].中国地质,2013,40(5):1644-1654.Li Bing,Chao Daichao,Wei Mingjun,et al.The application of electromagnetic sounding method to deep iron ore exploration:A case study of the Wuyang iron mining area of Henan[J].Geology in China,2013,40(5):1644-1654.
[7]王振军,李伟明,原波.山东三山岛-新立-仓上金矿床构造叠加晕特征浅析[J].黄金科学技术,2013,21(4):48-53.Wang Zhenjun,Li Weiming,Yuan Bo.Features of structural superimposed halos in Sanshandao-Xinli-Cangshang gold deposits,Shandong Province[J].Gold Science and Technology,2013,21(4):48-53.
[8]宋明春,张军进,张丕建,等.胶东三山岛北部海域超大型金矿床的发现及其构造-岩浆背景[J].地质学报,2015,89(2):365-383.Song Mingchun,Zhang Junjin,Zhang Pijian,et al.Discovery and tectonic-magmatic background of superlarge gold deposit in offshore of northern Sanshandao,Shandong Peninsula,China[J].Acta Geologica Sinica,2015,89(2):365-383.
[9]王友芳,孙世福,张荣敏,等.山东省莱州市仓上金矿北部含金破碎蚀变带物探普查成果报告[R].济南:山东省物化探勘查院,2003.Wang Youfang,Sun Shifu,Zhang Rongmin,et al.Results of geophysical survey of gold bearing fragmentation alteration zone in northern Cangshang gold deposit,Laizhou,Shandong[R].Jinan:Shandong Institute of Geophysical and Geochemical Exploration,2003.
[10]董坤,薄杨.V8工作站CSAMT勘探成果三维可视化研究[J].赤峰学院学报(自然科学版),2013,29(5):44-46.Dong Kun,Bo Yang.Research on 3D visualization of CSAMT exploration results of V8 workstation[J].Journal of Chifeng University(Natural Science Edition),2013,29(5):44-46.
[11]王若,王妙月,底青云,等.CSAMT三维单分量有限元正演[J].地球物理学进展,2014,29(2):839-845.Wang Ruo,Wang Miaoyue,Di Qingyun,et al.3DICCSAMT modeling using finite element method[J].Progress in Geophysics,2014,29(2):839-845.
[12]段文旭,肖宏跃,刘垒,等.CSAMT方法在铁矿勘探中的应用[J].物探化探计算技术,2014,36(2):190-193.Duan Wenxu,Xiao Hongyue,Liu Lei,et al.Application of the CSAMT in iron mine exploration[J].Computing Techniques for Geophysical and Geochemical Exploration,2014,36(2):190-193.
[13]底青云,王妙月,石昆法,等.高分辨V6系统在矿山顶板涌水隐患中的应用研究[J].地球物理学报,2002,45(5):744-748.Di Qingyun,Wang Miaoyue,Shi Kunfa,et al.An applied study on prevention of water bursting disaster in mines with the high resolution V6 system[J].Chinese Journal of Geophysics,2002,45(5):744-748.
[14]夏训银,王身龙,王洪生,等.CSAMT方法在铁路隧道勘探中的应用[J].勘察科学技术,2006(4):61-64.Xia Xunyin,Wang Shenlong,Wang Hongsheng,et al.Application of CSAMT to exploration of railway tunnel[J].Site Investigation Science and Technology,2006(4):61-64.
[15]董晴晴,冯欣欣.AMT方法在深部断裂构造识别中的应用——以南吕-欣木金矿区为例[J].山东国土资源,2016,32(10):48-51.Dong Qingqing,Feng Xinxin.Application of AMT technology in identifying deep fault structures——setting Nanlü-Xinmu gold mine as an example[J].Shandong Land and Resources,2016,32(10):48-51.
[16]韦乖强,赵慧,赵秀玲,等.CSAMT在隐伏地质构造勘查中的三维可视化应用[J].山东国土资源,2015,31(4):56-58.Wei Guaiqiang,Zhao Hui,Zhao Xiuling,et al.Application of three-dimensional visualization of CSAMT in exploring concealed geological structures[J].Shandong Land and Resources,2015,31(4):56-58.
[17]于昌明.CSAMT方法在寻找隐伏金矿中的应用[J].地球物理学报,1998,41(1):133-138.Yu Changming.The application of CSAMT method in looking for hidden gold mine[J].Acta Geophysica Sinica,1998,41(1):133-138.