Targeting potential cobalt deposits through integration of helicopter-borne magnetic and stream sediment data: Insights from the Bou Azzer Inlier, Central Anti-Atlas, Morocco

Abstract

The study was conducted in the Bou Azzer-El Graara inlier, located in the Central Anti-Atlas chain of Morocco. It is based on a methodological approach aimed at deducing the structural framework of the region and establishing the spatial distribution of geochemical associations to map areas with high cobalt potential. To achieve this, a comprehensive analysis of helicopter-borne magnetic and stream sediment geochemical data was carried out. The magnetic data included the residual magnetic field map (RMI) and the reduced-to-pole map (RTP), which were used for lithological analysis. These maps helped with identifying magnetic anomalies, some of which are associated with the Bou Azzer ophiolitic complex that hosts cobalt mineralization. Additionally, the tilt derivative (TDR) and CET transformation were applied for structural purposes, enabling the mapping of magnetic lineaments oriented WNW-ESE, NE-SW, and E-W. A depth estimation map of magnetic sources was also produced using the Euler deconvolution method (ED), revealing depths ranging from 60 m to 5900 m. Stream sediment geochemical data were processed using factor analysis, further refined by the GMPI method. This approach identified three main geochemical associations: first association: Co-As-Au-Cu, second association: Ni-Cr, and third association: Fe. An in-depth analysis of the results using fuzzy logic was carried out on the metallotects of cobaltiferous mineralizations, highlighting a significant correlation between structural complexity and the spatial distribution of geochemical anomalies. This modeling, presented as a mineral prospectivity map, led to the identification of five potential zones for the discovery of new cobaltiferous occurrences. This validation underscores the relevance and efficiency of the methods applied in mineral exploration within the region.