Two-dimensional resistivity imaging in the Kestelek boron area by VLF and DC resistivity methods

A VLF and DC resistivity investigation was conducted in the Kestelek area, western Turkey, to determine the two-dimensional images of the boron deposits. The two-dimensional resistivity images were obtained by the inversion of tipper and resistivity data for VLF and DC resistivity methods, respectively. The VLF tipper data also were improved applying the Fraser and Karous & Hjelt (K&H) filtering to delineate the boundaries of the subsurface boron deposits. The main findings are: (1) moderate (> 25 Ωm) and relatively high (> 40 Ωm) resistivity zones in the two-dimensional models, which is mostly supported by the K&H real part of tipper as the negative current density peaks, may be interpreted as middle level of potatoes type colemanite and lower level of crystal type colemanite boron deposits inside the conductive units, respectively. (2) Transition from positive peaks (conductive zones) to negative peaks (resistive zones) in the K&H real part of tipper current density pseudosections may indicate the potential locations of the boron deposits. (3) Drilling well results obtained around two profiles of the study area are consistent with distribution of the resistive boron deposits in the two-dimensional resistivity models and K&H real part of tipper filtering images.

► In 2-D models, boron deposits produce strong variations in subsurface resistivity.
► The consistency between VLF and DC 2-D resistivity models is an interesting finding.
► We obtained quite good characteristic strong VLF resistivity and phase responses.
► Locations of the boron deposits may be determined by following K&H inflections.
► The combination of two methods can be used for 2-D imaging of buried boron deposits.