Details of the Abstract
| Title of paper | 3D Inversion of Transient Electromagnetic Data - Imaging the Roter Kamm Impact Crater, Namibia |
| List of authors | Nienhaus, H., Yogeshwar, P., Mörbe, W., Tezkan, B., Liu, Y., Lushetile, B., Melles, M. |
| Affiliation(s) |
University of Cologne, Institute of Geophysics and Meteorology, Cologne, University of Cologne, Institute of Geophysics and Meteorology, Cologne, University of Cologne, Institute of Geophysics and Meteorology, Cologne, University of Cologne, Institute of Geophysics and Meteorology, Cologne, China University of Geosciences, Department of Geophysics, Wuhan, Ministry of Mines and Energy, Geological Survey of Namibia, Windhoek, University of Cologne, Institute of Geology and Mineralogy, Cologne |
| Summary | The Roter Kamm Crater is a meteoritic impact crater in the Tsau //Khaeb (Sperrgebiet) National Park in southern Namibia. Access to the national park, a former diamond mining area, had been restricted for approximately one century until 2008. Since only a limited number of studies were carried out, we provide a new model of the Roter Kamm Crater’s sedimentary infill and determine its geometry and maximum thickness. One transect of the Roter Kamm was explored using a fixed-loop transient electromagnetic (TEM) configuration. The fixed-loop setup uses one large transmitter loop to record data at multiple receiver positions. To complement this data set, we additionally carried out single-loop TEM and sparse audiomagnetotelluric (AMT) measurements to fully image the Roter Kamm Crater at two perpendicular profiles and ensure that we resolve all necessary depth ranges equally well. We inverted the TEM data from both set-ups using a novel 3D TEM inversion algorithm. The inversion of the fixed-loop data used significantly less computational resources than the single-loop inversion, because of a greatly reduced number of transmitters. The 3D TEM and 2D AMT results are in an exceptional agreement with each other. The resistivity models reveal a large planoconvex lens-shaped conductor within the crater rims. We interpret the lower boundary of it as the transition from sediments to brecciated bedrock and the decreased resistivity as higher moisture content of the aeolian sands deposited in the crater’s sedimentary infill. |
| Session Keyword | 3.0 EM methods for exploration (geothermal, mineral resources, etc.) |
| File upload |
3.0_3d_inversion_of_transient_nienhaus_07.pdf
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