Detecting resistivity and induced polarization anomalies of galena veins in the presence of highly chargeable and conductive geological units at Daryan barite deposit in Iran

Abstract

Assessment of resistivity and induced polarization (IP) data for metallic sulfide ore explorations is considered a routine task in the mining industry. The success in these surveys would be challenging if the sulfide ore lies within conductive and chargeable geological units. In this study, the resistivity and IP data of the Daryan area in northwestern Iran were examined for the detection of high-grade galena veins hosted by the Kahar Formation, a complex geological formation with several conductive and chargeable geological units. To facilitate the geophysical interpretations, a simple approach was adopted to solve the problem, and it was shown that a combination of correct geophysical modeling and approximate clustering of physical properties can help to check and revise (if necessary) the geological model or geophysical interpretations. In the Daryan area, the barite mineralization had high resistivity and low IP anomalies. More importantly, it was found that the highest IP and the lowest resistivity values were not the responses of galena mineralization but the graphite-rich shale. Thus, in complicated situations, the data should be treated and interpreted carefully because the “rules of thumb” may not work. This fact highlighted that prioritization of anomalies based on geophysical models alone is not an appropriate strategy in mineral exploration, and the interpretations must always be evaluated with geology. Moreover, it was discussed that both volume concentration and style of conductive minerals can be vital for creating elusive electrical responses, thus caution should be taken while interpreting electrical models in areas with complicated geology.