3D modeling of a shallow polymetallic ore deposit using 3D inversion of magnetic, electrical resistivity and induced polarization data: a case study from Nahavand, Hamedan Province, Iran

Abstract

The Nahavand polymetallic deposit, located within the metamorphic-magmatic Sanandaj–Sirjan zone, is one of the most important metallogenic zones in the Hamedan Province of Iran. Different ore mineralization has been found in the study area, including Au, Cu, Fe and Zn. Due to trenches lithological sampling analysis, the type of mineralization for this ore deposit is podiform, which has high expansion in all three dimensions (length, width and depth). In this paper, to approach a realistic interpretation, the parameters integration of geophysical surveys including magnetic susceptibility, electrical resistivity, and induced polarization has been simultaneously carried out in the study area. We applied the Li–Oldenburg algorithm and the smoothness-constrained least-squares method to invert magnetic, resistivity data, and induced polarization data in three dimensions. The efficiency of these inversion methods and programs is demonstrated with 3D inversion modeling of both synthetic and field data. The 3D inversion results of whole different geophysical methods determine the depth of the top and bottom of a polymetallic ore deposit and also show that the mineralization controlled by the geological faults and most of the slopes of the mineralization have a direction to the south.