dipole-dipole data: the Enfermarias Zn-Pb (Ag, Sb, Au)

The Enfermarias Zn-Pb(Ag, Sb, Au) prospect, located in the Moura-Ficalho region (Alentejo, Portugal), was intensively explored during 1980s. A drilling programme was successful, intersect-ing massive and disseminated sulphide mineralizations. The geological and geophysical data set available for Enfermarias is quite vast and comprises 13 borehole geological logs, as well as grav-ity, magnetic and resistivity data. In this paper, the dipole-dipole resistivity surveys are re-examined and interpreted using both 2D and 3D inversion to provide an interesting comparison of the two dif-ferent approaches. Results from gravity data modelling and data from borehole logs are used as independent validity tests on the quality of the results. The 2D and 3D models indicate a conductive overburden covering more resistive bedrock, which appears at a depth of 70–100 m in the western part of the profiles. Results obtained from 3D inversion, however, show a very clear separation of the most resistive domains in the two different bodies, whereas this separation does not appear in the 2D models. The 3D model also shows a high-er degree of spatial continuity than the partial 2D models, which are, in general, richer in short-wavelength anomalies, and show a higher variation from profile to profile