Application of distributed 3D wide field electromagnetic method in the exploration of rich iron ore in the thick covered area of Litun

To reveal the fine geological structure in the deep Litun iron-rich deposit in the thick coverage area, distributed three-dimensional wide field electromagnetic detection was carried out. It uses high-order 2ⁿ sequence pseudo-random signal, can transmit 49 frequencies at a time and receive at the same time, realize distributed rolling measurement, and obtain the geoelectric characteristics of 2000m 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 constraints for gravity-magnetic joint inversion and delineates new prospecting targets in combination with metallogenic laws. The results show that the distributed three-dimensional wide field electromagnetic method is an effective detection method to obtain the deep fine geological structure in the thick coverage area and has a good application prospect.