| VTEM electromagnetic system as a relatively advanced aviation transient electromagnetic measurement system In foreign counties has the advantages of strong resolution large.and other technical advantages.The VTEM system is the latest Chinese aviation transient electromagnetic method equipment imported from abroad.In recent years,it has been tentative stage in domestic aviation electromagnetic prospecting field,and it has achieved good experimental results.In this paper,in combination with the VETM aviation transient electromagnetic measurement experiment imported from abroad by the Nuclear Industry Aeromagnetic Remote Sensing Center,has carried out the transient electromagnetic VTEM system test project in Xinjiang Huangtupo.In order to develop and utilize the system through the experimental research work in the known deposit area to provide effective technical support for the exploration of polymetallic mineral resources in China.In this paper,based on electromagnetic wave foundamental equation,briefly introduce the propadation regulation of electromagnetic waves in the medium,formation principle of secondary field induced by induction and the secondary field decays as time passes From the theory of transient electromagnetic field,discuss the main parameters of avionics data processing,namely the calculation methods of time constant,apparent resistivity,apparent susceptibility and depth visual resistivity imaging technology,and the physical meaning of each parameter.With the help of the Maxwell transient electromagnetic simulation software,we simulate and analyze the electromagnetic response characteristics of the good-guided plate-like body with different geometric parameters.The results show that the electromagnetic response of the low-resistance anomalous body is obvious and has a good regularity.Secondly,based on the avionics and aeromagnetic data measured in the test area,calculating time constants,apparent resistivity at different depths,total aeromagnetic field and apparent magnetic susceptibility,plotting the image maps and comprehensive section diagrams of each parameter.Based on the upper results,mingling with the known geological conditions and distribution data of the deposits in the test area,the electromagnetic response characteristics of the known ore bodies and the avionics and aeromagnetic anomalies are compared and analyzed.The test results show that there are obvious avionics and aeromagnetic anomalies above the known sulfide metal ore,and the aerospace anomaly range and the low resistance body space reflected by the weak magnetic anomaly area are in good agreement with the known main orebody space location.Finally,we based on the apparent resistivity and apparent susceptibility inversion profiles,applying visual resistivity three-dimensional visualization imaging and aeromagnetic three-dimensional inversion techniques to visualize the calculated apparent resistivity and the inverted visual susceptibility,showing the spatial distribution of anomalies immediatly.Also demonstrates the inversion low-resistance anomalous body is consistent with the distribution of known orebodies in spatial distribution,indicating that aviation transient electromagnetic method has good prospecting effect in polymetallic ore exploration. |
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