ABSTRACT
In the past decades,
several iron ore occurrences have been discovered in the Precambrian Belt of
southern Cameroon, with focus on their economic potential, and little attention
on the deposit type. However, few studies have been geared towards
understanding the different deposit types within this region. This paper seeks
to provide new insight on the different styles of iron ore mineralisation of
two potential, yet least studied iron ore deposits in this region in addition
to enhancing exploration efforts within the different prospects. Petrology and
geochemistry of rock samples from the Binga and Djadom iron prospects in
southern Cameroon are investigated. The structural disposition of the prospects
was mapped and cores described, sampled and subsequently analysed to enhance
the understanding of the alteration mineralogy, ore mineralogy and textural
features of the iron-bearing lithologies. Polished thin sections were studied
by standard microscopy while the bulk rock geochemistry was determined by X-ray
fluorescence (XRF) for major and trace elements. At Binga, the main rock types
are magnetite gneisses, amphibolites, quartz-biotite gneisses, and mafic
intrusions, while the main rocks encountered at Djadom are magnetite gneisses,
amphibolitic BIFs, quartz-biotite gneisses, amphibolites and fault rocks. At
both prospects, the target lithology for iron ore is the magnetite gneiss. The
magnetite gneisses at the Binga prospect are weakly to moderately foliated, but
strongly foliated at Djadom, and both contain fractures that are healed by
irregular magnetite. Magnetite is anhedral to euhedral in outline and it is
closely associated with amphibole, garnet and pyroxene. Iron content of the
magnetite gneisses ranges from 17.44 - 33.40 wt% (at Binga) and 27.73 - 43.39
wt% (at Djadom) and the ore enrichment process involved progressive loss of
silica and aluminium. Trace element concentrations show high contents of Ba,
Zn, Cu and V but lower abundances of Sr and Zr, as well as low values for Ti in
both prospects. At the Binga iron ore prospect, TiO2 and Al2O3 display a linear co-variation with Zr,
while in the Djadom prospect, TiO2, Al2O3 and MgO display a negative
co-variation with Zr. The origin of the former could be linked to a magmatic
fluid-related process, while the genesis of the later is tied to both skarn
formation and hydrothermal enrichment.