Details of the Abstract
| Title of paper | Joint inversion of MT and CSEM data for Deep Mineral Exploration: Case Study of Koillismaa Layered Intrusion Complex |
| List of authors | S. Védrine, C. Patzer, F. Bretaudeau, R., Rochlitz, U. Autio, B. Kim, F. Vermeersch, J. Kamm, C. Truffert, M. Darnet |
| Affiliation(s) | BRGM France, Geological Survey of Finland, BRGM France, Leibniz Institute for Applied Geophysics Hanover Germany, Geological Survey of Finland, BRGM France, IRIS Instruments France, Geological Survey of Finland, IRIS Instruments France, BRGM France |
| Summary | A large-scale magnetotelluric (MT), controlled-source electromagnetic (CSEM), and deep induced polarization (IP) acquisition campaign was carried out around the Koillismaa Layered Intrusion Complex in northeastern Finland. The objective was to characterize deep-seated ultramafic intrusion with anomalous electrical and chargeability properties at approximately 1.4 km depth (as inferred by core values) and the associated alteration zones. MT is effective for targeting the deepest parts of the subsurface. However, its vertical resolution can be limited due to the plane wave nature of its sources. CSEM enhances and densifies data coverage by using a high number of powerful active current sources in the near field or transient zone of the receivers and by using less demanding measurement systems. Increasing transmitter (Tx) and receiver (Rx) points will, in turn, improve the vertical and lateral resolution at intermediate depths (< 3 km). In this paper, our goal is to present the key steps of combining MT and CSEM, encompassing survey design and logistics, data processing, and the final joint inversion. We display the isotropic resistivity models obtained from CSEM and MT individual inversions using a finite-element code. Additionally, we introduce the joint MT-CSEM inversion model, which merges the different sensitivities and resolutions of both methods and aligns with the expected geology of the area. Finally, we discuss future developments, such as exhaustive synthetic studies to validate our findings, IP effect correction or anisotropic inversions. |
| Session Keyword | 3.0 EM methods for exploration (geothermal, mineral resources, etc.) |
| File upload |
3.0_joint_inversion_of_mt_and_vedrine_01.pdf
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