3D depth estimation of Mingo’o’s iron mineralization from outcrop data and geophysical analysis (South Cameroon, northern edge of the Congo Craton)

Abstract

Abstract The Mingo’o locality belongs to the Nyong Complex, located on the northern edge of the Congo Craton. In order to estimate the depth parameter of iron mineralization, outcrop studies, and ground magnetic geophysical surveys have been conducted. The petrographic analysis of outcrops reveals that Mingo’o’s banded iron formations comprise quartz–hematite BIFs (QHB) and quartz–magnetite BIFs (QMB). Also, the rocks are magnetic, with well-expressed millimetric dark bands of magnetite and hematite alternating with light bands of quartz. Magnetite and hematite crystals ranged in size from 0.1 to 3 mm, while quartz crystals were between 0.1 and 2 mm. The use of a ground magnetic survey reveals the presence of BIFs highlighted by total magnetic intensity, reduction to the equator, and total gradient, with values of 524.9–8,866.7 nT, -1,464.9 to -41.8 nT, and 36.781–86.470 nT/m, respectively. The 3D modeling shows that magnetic susceptibility values ranging between 0.6 and 3 SI are associated with BIFs. This model shows that the iron mineralization body extends 800 m N-S and 1,000 m E-W, with depth > 500 m, which is also confirmed by the Euler deconvolution method. The correlation of all these results shows a high BIF occurence in the elevated zone (> 400 m). This is a similar hypothesis to some of the previous surveys executed on the northern edge of the Congo Craton.

Keywords

• 3D modeling
• iron mineralization
• ground magnetic survey
• Nyong Complex