Citation: | ZHU Yuzhen, ZHANG Wenyan, SHAO Guihang, GAO Zhijun, RU Liang, YAN Bing, YANG Yang. 2024. Application of distributed 3D wide field electromagnetic method in the exploration of high-grade iron ore in the thick covered area of Litun in Qihe−Yucheng, Shandong Province. Geological Bulletin of China, 43(9): 1555-1564. doi: 10.12097/gbc.2022.09.023 |
In recent years, significant progress has been made in the exploration of high-grade iron ores in the Litun heavy-cover area of Qihe—Yucheng, Shandong Province. But the Cenozoic thickness (900~1100 m) in this area is so large that the magnetic iron ore is deeply buried. The geophysical condition caused by the iron ore is thus abnormally weak, and the prospecting is difficult. To reveal the deep geological structure of high-grade iron ore in the Litun, distributed three-dimensional wide field electromagnetic detection was carried out. The high-order 2n sequence pseudo-random signal was used, which can transmit 49 frequencies at a time and receive at the same time, realize distributed rolling measurement, and obtain the geoelectric characteristics of 2000 m underground. Based on this, a detailed interpretation of the underground geological structure was carried out, and a three-dimensional geological model of the key research area was constructed. The interpretation results were in good agreement with the existing seismic and drilling information. It provides effective geological structure constraints for gravity-magnetic joint inversion. Delineates new prospecting targets in combination with gravity and magnetic characteristics and metallogenic laws. The results show that the distributed three-dimensional wide field electromagnetic method is an effective detection method to obtain the deep geological structure in the heavy-cover area and has a good application prospect.
[1] | He J S. 2019. Theory and technology of wide field electromagnetic method[J]. The Chinese Journal of Nonferrous Metals, 29(9): 1809−1816(in Chinese with English abstract). |
[2] | He J S. 2020. New research progress in theory and application of wide field electromagnetic method[J]. Geophysical and Geochemical Exploration, 44(5): 985−990(in Chinese with English abstract). |
[3] | He J S, Yang Y, Li D Q, et al. 2020. Method and system for generating high−order pseudo−random electromagnetic prospecting signal[P]. CN Patent, 202010344733.2 (in Chinese with English abstract). |
[4] | Hou Z, Chen X, Yu C C, et al. 2021. Characteristics of the geological deep structure in QiHe−Yucheng area of Shandong: Characteristics of the geological deep structure in QiHe−Yucheng area of Shandong[J]. Progress in Geophysics, 36(3): 1070−1081(in Chinese with English abstract). |
[5] | Shen L J, Zhu Y Z, Gao Z J. 2020. Paimary Study on Geological Characteristics of Litun Rock Mass in Paimary Study on Geological Characteristics of Litun Rock Mass in[J]. Shandong Land and Resources, 36(2): 23−29(in Chinese with English abstract). |
[6] | Shen L J, Zhu Y Z, Wang H H, et al. 2021a. Geochemical characteristics and geological significance of Litun iron ore deposit in Qihe—Yucheng area, Shandong Province[J]. Geological Review, 67(1): 84−98(in Chinese with English abstract). |
[7] | Shen L J, Zhu Y Z, Li S, et al. 2021b. Application of Geophysical Logging in Deep Metallic Ore Prospecting[J]. Well Logging Technology, 45(4): 431−438(in Chinese with English abstract). |
[8] | Wang H H, Li X Z, Shen L J, et al. 2021a. Geological Characteristics and Metallogenic Model of "Yucheng Type" Rich Iron Deposit in Qihe Yucheng Area in Shandong Province[J]. Shandong Land and Resources, 37(9): 26−35(in Chinese with English abstract). |
[9] | Wang H H, Shen L J, Wang D D, et al. 2021b. Study on Mesozoic magmatic intrusion and Paleozoic multi−mineral genesis mechanism in Huanghebei Coalfield, Shandong Province[J]. Coal Geology & Exploration, 49(2): 83−92(in Chinese with English abstract). |
[10] | Wang R S, Hao X Z, Hu L, et al. 2023. Discovery of skarn iron−rich deposit based on gravity and magnetic data in the Qihe−Yucheng, Shandong Province: Enlightenment to prospecting of the superdeep coverage area[J]. Geology in China, 50(2): 331−346(in Chinese with English abstract). |
[11] | Yang Y, He J S, Li D Q. 2021. Energy distribution and effective components analysis of 2n sequence pseudo−random signal[J]. Transactions of Nonferrous Metals Society of China, 31(7): 2102−2115. doi: 10.1016/S1003-6326(21)65641-8 |
[12] | Yang Y, He J S, Ling F, et al. 2022. Distributed wide field electromagnetic method based on high−order 2n sequence pseudo random signal[J]. Transactions of Nonferrous Metals Society of China, 32(5): 1609−1622. doi: 10.1016/S1003-6326(22)65897-7 |
[13] | Yang Y, Zhou C, Zhang H, et al. 2023. Denoising CSEM data using least−squares method based on mixed basis of Fourier series and Legendre polynomials[J]. IEEE Transactions on Geoscience and Remote Sensing, 61: 1−12. |
[14] | Zhang Z Q, Li Y P, Wang H H, et al. 2016. Large high−grade iron ore deposit is found in Qihe−Yucheng area of Shandong Province[J]. Shandong Land and Resources, 32(5): 94(in Chinese with English abstract). |
[15] | Zhou M L, Ru L, Zhu Y Z, et al. 2021. Magnetic field characteristics and ore prediction in Qihe−Yucheng area of Shandong Province[J]. Geophysical and Geochemical Exploration, 45(2): 301−307(in Chinese with English abstract). |
[16] | Zhu Y Z, Zhou M L, Gao Z J, et al. 2018. The discovery of the Qihe−Yucheng skarn type rich iron deposit in Shandong and its exploration significance[J]. Geological Bulletin of China, 37(5): 938−944(in Chinese with English abstract). |
[17] | Zhu Y Z, Qiang J K, Wang L F, et al. 2019. Three−dimensional inversion analysis of magnetic data from deep buried iron ore and prediction of prospecting target area[J]. Geophysical and Geochemical Exploration, 43(6): 1182−1190(in Chinese with English abstract). |
[18] | 何继善. 2019. 大深度高精度广域电磁勘探理论与技术[J]. 中国有色金属学报, 29(9): 1809−1816. |
[19] | 何继善. 2020. 广域电磁法理论及应用研究的新进展[J]. 物探与化探, 44(5): 985−990. |
[20] | 何继善, 杨洋, 李帝铨, 等. 2021. 一种高阶伪随机电磁勘探信号生成方法及系统[P]. 山东省: CN202010344733.2. |
[21] | 侯征, 陈雄, 于长春, 等. 2021. 山东齐河—禹城地区深部地质构造特征——来自大地电磁的证据[J]. 地球物理学进展, 36(3): 1070−1081. doi: 10.6038/pg2021EE0422 |
[22] | 沈立军, 朱裕振, 高志军. 2020. 山东齐河—禹城富铁矿区李屯岩体地质特征初探[J]. 山东国土资源, 36(2): 23−29. |
[23] | 沈立军, 朱裕振, 王怀洪, 等. 2021a. 山东齐河—禹城地区李屯富铁矿床地球化学特征及地质意义[J]. 地质论评, 67(1): 84−98. doi: 10.16509/j.georeview.2021.01.007 |
[24] | 沈立军, 朱裕振, 李双, 等. 2021b. 地球物理测井在金属矿深部找矿中的应用[J]. 测井技术, 45(4): 431−438. doi: 10.16489/j.issn.1004-1338.2021.04.015 |
[25] | 王怀洪, 李秀章, 沈立军, 等. 2021a. 山东齐河—禹城地区“禹城式”富铁矿地质特征与成矿模式[J]. 山东国土资源, 37(9): 26−35. |
[26] | 王怀洪, 沈立军, 王东东, 等. 2021b. 山东黄河北煤田中生代岩浆侵入与古生代多矿产成因机制[J]. 煤田地质与勘探, 49(2): 83−92. doi: 10.3969/j.issn.1001-1986.2021.02.011 |
[27] | 王润生, 郝兴中, 胡蕾, 等. 2023. 基于重磁资料在山东齐河—禹城探获矽卡岩型富铁矿及其对超深覆盖区找矿的启示[J]. 中国地质, 50(2): 331−346. |
[28] | 张增奇, 李英平, 王怀洪, 等. 2016. 山东省齐河禹城地区发现大型富铁矿[J]. 山东国土资源, 32(5): 94. doi: 10.3969/j.issn.1672-6979.2016.05.020 |
[29] | 周明磊, 汝亮, 朱裕振, 等. 2021. 山东齐河—禹城地区重磁场特征及找矿预测[J]. 物探与化探, 45(2): 301−307. |
[30] | 朱裕振, 周明磊, 高志军, 等. 2018. 山东齐河—禹城地区矽卡岩型富铁矿的发现及其意义[J]. 地质通报, 37(5): 938−944. |
[31] | 朱裕振, 强建科, 王林飞, 等. 2019. 深埋铁矿磁测数据三维反演分析与找矿靶区预测[J]. 物探与化探, 43(6): 1182−1190. |
Geological map of Pre-Neogene bedrock in Litun mining area
Anomaly characteristics of high-precision geomagnetization pole plane
The high-order 2n sequence pseudo-random signal
Field working method for and distributed WFEM
LG340 line 595 point raw data
Comparison of electric field values before and after denoising
S190 line wide-area electromagnetic resistivity profile
Wide-area electromagnetic 3D model of Xiaoliuzhuang mining section
Comparison of the 00-line cross section of the wide-area electromagnetic method and the seismic section
Gravity magnetoelectric comprehensive geophysical profile