Geochemical prospecting for gold in the area north of Isanlu, Nigeria

A combined heavy mineral and stream sediment survey was carried out in the area north of Isanlu to delineate potential areas for a detailed search for gold deposits. The geology of the area is typical of the basement of SW Nigeria with gneisses, schists, amphibolites and granites. Mineralization comprises gold/sulphide-bearing quartz veins and amphibolites.

Data obtained from the stream sediment survey were subjected to statistical interpretation and it was found that the log-normal pattern appears to be the one most applicable to the element distributions. No indicator for gold has been identified, but the significant correlation that exists between Pb/Cu and Pb/Zn was taken to distinguish vein mineralization from disseminated mineralization in amphibolites.

The heavy mineral survey, which was intended to simply check for gold occurrences in the field, also proved useful in detecting other anomalies later confirmed by the stream sediment survey. It was found to be a better exploration tool for gold at the reconnaissance stage. The overall high level of gold in the drainage indicates a metallogenic area favourable for gold. The survey succeeded in delineating possible gold targets worthy of follow-up.