Journal de géologie et géophysique
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Characterization of Iron Ore Deposit using 2D Resistivity Imaging and Induced Polarization Techniques at Diddaye: Potiskum Area, Northeastern Nigeria

Aliyu Mohammed Lawan

2D Electrical resistivity imaging and Induced polarization (IP) techniques were used to characterize Iron Ore deposit at Diddaye-Potiskum area of Yobe State, Northeastern Nigeria. The area lies between latitudes 11⁰46'00'' and 11⁰56' 00'' N, and longitudes 11⁰00'00'' and 11⁰10'00'' E. The survey was targeted at determining resistivity and chargeability values that are associated with the iron ore deposit and determining possible depth, thickness of the deposit. The protocol chosen were the Wenner-Schlumberger array and dipole-dipole for 2D resistivity and induced polarization imaging respectively. Data processing and interpretation were carried out using RES2DINV software. This research characterized the alluvium deposit in the study area into two: the alluvium deposit that is enriched with iron ore and alluvium deposit with disseminated iron ore. The portion of the models characterized by resistivity and chargeability values of 32 Ωm to 886 Ωm and 0.376 msec to 2.4 msec respectively is inferred as highly enriched iron ore alluvium; The other part is the portion of alluvium with disseminated iron ore. The range of resistivity and chargeability values of this portion are respectively 252 Ωm to 1161 Ωm and 1.28 msec to 12.11 msec. The study delineated high resistive medium to coarse sandstone with resistivity value that range from 3182 Ωm to 124309 Ωm at fringes of depth range between 9 m to 11 m at models of profile one, four and six. The fracture inferred in this research has been suggested to be filled with the resistive medium to coarse sandstone. This fracture zone cannot be mapped with IP since it is sensitive to disseminated iron ore that the zone probably contains. Therefore it can be concluded that the occurrence of iron ore deposit is probably more at northeast and southwest directions of the survey area that is profile one to six. It can also be inferred that the iron ore deposit is striking in the Northeast- Southwestdirection.