2D Inversion of DCR and Time Domain IP data: an example from ore exploration

Abstract:

Ore deposits often appear as disseminated sulfidic materials. Exploring these deposits with the Direct Current Resistivity (DCR) method alone is challenging because the resistivity signatures caused by disseminated material is often hard to detect. The Time-domain Induced Polarization (TDIP) method, on the other hand, is qualified to detect areas with disseminated sulfidic ores due to large electrode polarization effects which result in large chargeability anomalies. By employing both methods we gain information about both, the resistivity and the chargeability distribution of the subsurface.
On the poster we present the current state of the development of a 2D smoothness constraint inversion algorithm for DCR and TDIP data. The implemented forward algorithm uses a Finite Element approach with an unstructured mesh. The model parameters resistivity and chargeability are connected by either a simple conductivity pertubation approach or a complex conductivity approach.
As a case study, the 2D inversion results of DCR/TDIP and RMT data obtained during a survey on a sulfidic copper ore deposit in Turkey are presented. The presence of an ore deposit is indicated by areas with low resistivity and significantly high chargeability in the inversion models.
This work is part of the BMBF/TUEBITAK funded project ``Two-dimensional joint interpretation of Radiomagnetotellurics (RMT), Direct Current Resistivity (DCR) and Induced Polarization (IP) data: an example from ore exploration''.