Exploration targeting of copper deposits using staged factor analysis, geochemical mineralization prospectivity index, and fractal model (Western Anti-Atlas, Morocco)

Abstract

The present work aims to identify the geochemical signatures of copper deposits in the Igherm area (Anti-Atlas, Morocco) using stream sediment data. We applied factor analysis on the data normalized by log transformation. This approach identified three geochemical data associations (F1, F2, and F3) which were then used to calculate the values of the geochemical prospectivity index (GPMI). The results indicated that the large GMPI Cu values correlate strongly with the surface indices. A concentration-surface (C-A) fractal classification was applied to separate the geochemical anomalies from the regional background. To recognize and geo-position the significant geochemical signatures of the deposit, we applied the prediction zone (P-A) plot. A geographic information system (GIS) was used to define the spatial distribution of the anomalies at the sub-watershed level. The results represent the first approach to evaluating potential mineral resources at the scale of the Anti-Atlas: 90% of the anomalous sub-catchments mapped are located along the Precambrian-Cambrian transition (Base Series), 67% are traversed by major tectonic faults, and 40% contain copper showings and/or deposits. The remaining 60% are devoid of any visible surface copper occurrences. They constitute promising areas for future exploration of Cu deposits hidden under the Cambrian cover.