Prospecting of Gold Mineralization Indices in the Eastern of Meiganga (Adamawa Region, Cameroon)

Abstract

In order to search for secondary gold in the eastern part of Meiganga, alluvial and eluvial field explorations, geological and mineralogical, morphoscopical studies have been carried out in Fell, Gbatoua, and Kombo-Laka. Alluvial and eluvial field explorations have allowed locating six main concentrations points of gold and heavy minerals (olivine, zoisite, rutile, zircon, …). Many rocks types are found: volcano-sedimentary (basalts, rhyolites, conglomerates), metamorphic (quartzites, chloritoschists, schists) to deteriorated quartzic and ironic other (consolidated clays). Quartzites are the most represented in the whole area. Alluviums are concentrated in special zones of waterways. One eluvial pit described reveals a sequence of three horizons from the bottom to top: horizon C with residual quartzitic parental rock, a light red (10YR/8/7 to 2.5YR/2/8) horizon B with clays and sands and a yellowish brown (2.5YR/8/6 to 10YR/8/6) horizon A with clays. Grain size distribution of alluvium shows they are globally sandy sediment, with some predominance of gravels and/or coarse sand grains. The “Sorting Index” values show that these sediments are well sorted. The heavy minerals reveal the presence of zircon, zo?site, magnetite, hematite, ilmenite and opaque minerals. Statistics studies done on these minerals show a predominance of opaque minerals and zoisite. Gold grains have been found in the top of horizon C and in the banks of Fel, Bandoungui, Sokour, Mifek and Wan Toro waterways. Their morphoscopical study shows mainly shiny sub-blunt with some shiny sub-angular and blunt grains. Their forms are nuggets, powders and dusts. Any form characterizes a locality. The mineralogical results obtained suggest that these mineralized sediments have a multiple origin source, which is supposed to be determined.