In the last three decades, electromagnetic methods are continuing to develop due to their proven usefulness in the search for massive sulfides. In tropical regions, the overburden is usually conducting. However the effect of this conducting layer is seldon taken into account while interpretating the EM data. this can cause considerable interpretation erros. In this work, we considered the overburden in-contact and not in-contact with the underlying conductor. Reduced scale model experiments were carried out to study the effects of the overburden on the EM anomalies of inclined tabular like bodies. With this objective, response parameters of the conductor and the overburden were varied. The target-conductor is represented in the model experiments by stainless steel sheets. These sheets are, larg compared the coil separation in order to simulated the behavior of a half-plane. The overburden is simulated by a conducting solution. To represented the case of a conductive-overburden the model is placed in galvanic contact with the solution. In case of the inductive-overburden the model is coupled to the overburden only inductively and did not have a galvanic contact. This situation is attained by keeping the model 1) totally out of the solution, and 2) partially in the solution but the model is covered by a resistive film to avoid the galvanic contact with the solution. In the presence of inductive-overburden, the anomalies are slightly attenuated. In the quadrature component the profile is inverted and an extra-peak appear in the case of low dipping models at higher induction numbers of the overburden and the model. Also the anomaly suffers a clockwise rotation which is intense for higher induction number of the conductor. Therefore, in the presence of an inductive-overburden the conductor appears to be more conducting and at higher depth than it really is. In the presence of a conductive-overburden, the anomaly amplitude are slightly enhanced and suffer an anticlockwise phase rotation, which is more intense at the lower induction number of the conductor. However, the other effects in the quadrature component, like the inversion and an appearance of the extra-peak, are similar to that of the inductive-overburden. Due to these effects of the conductive-overburden, the conductor appears to be at a shallower depth and less conducting than it actually is. These modifications in anomalies are caused by: a) The primary and secondary EM fields suffering attenuation and phase rotation when passing through a conducting overburden, b) an inductive interaction between the induced currents in the conductor and the overburden, and also, c) a redistribution of the currents in the overburden when the conductor is placed in it. In case of a conductive-overburden, currents are channeled in the conductor which is in galvanic contact with the less conducting overburden. On the other hand when a conductor covered with a resistive film is placed in the conducting solution, the currents are displaced and they crowd in the solution next to the boundary of the resistive film.
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