Approximate resistivity and susceptibility mapping from airborne electromagnetic and magnetic data, a case study for a geologically plausible porphyry copper unit in Iran | ||
| Journal of Mining and Environment | ||
| مقاله 19، دوره 4، شماره 2، مهر 2013، صفحه 133-146 اصل مقاله (1.44 M) | ||
| نوع مقاله: Case Study | ||
| شناسه دیجیتال (DOI): 10.22044/jme.2013.266 | ||
| نویسندگان | ||
| Maysam Abedi* 1؛ Gholam-Hossain Norouzi2؛ Nader Fathianpour3؛ Ali Gholami4 | ||
| 1Department of Mining Engineering, University of Tehran | ||
| 2Department of Mining Engineering, College of Engineering, University of Tehran, Iran | ||
| 3Department of Mining Engineering, Isfahan University of Technology, Iran | ||
| 4Institute of Geophysics, University of Tehran, Tehran, Iran | ||
| چکیده | ||
| This paper describes the application of approximate methods to invert airborne magnetic data as well as helicopter-borne frequency domain electromagnetic data in order to retrieve a joint model of magnetic susceptibility and electrical resistivity. The study area located in Semnan province of Iran consists of an arc-shaped porphyry andesite covered by sedimentary units which may have potential of mineral occurrences, especially porphyry copper. Based on previous studies, which assume a homogenous half-space earth model, two approximate methods involving the Siemon and the Mundry approaches are used in this study to generate a resistivity-depth image of underground geologically plausible porphyry unit derived from airborne electromagnetic data. The 3D visualization of the 1D inverted resistivity models along all flight lines provides a resistive geological unit which corresponds to the desired porphyry andesite. To reduce uncertainty arising from single geophysical model, i.e., the resistivity model acquired from the frequency domain electromagnetic data, a fast implementable approach for 3D inversion of magnetic data called the Lanczos bidiagonalization method is also applied to the large scale airborne magnetic data in order to construct a 3D distribution model of magnetic susceptibility, by which the obtained model consequently confirms the extension of an arc-shaped porphyry andesite at depth. The susceptible-resistive porphyry andesite model provided by integrated geophysical data indicates a thicker structure than what is shown on the geological map while extends down at depth. As a result, considering simultaneous interpretation of airborne magnetic and frequency domain electromagnetic data certainly yield lower uncertainty in the modeling of andesite unit as a potential source of copper occurrences. | ||
| کلیدواژهها | ||
| Electromagnetic and Magnetic data؛ Approximate inversion؛ Electrical resistivity؛ Magnetic susceptibility؛ Porphyry copper unit | ||
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