Mapping and documentation of lithological varieties and their corresponding geochemistry at the Kitongo uranium mineralization were concerned. The Kitongo U occurrence is hosted by granitic rocks that include interleaved sequences of metasedimentary and metavolcanic rocks of the collectively termed Poli Group. U-mineralization and Na-metasomatism are related and structurally controlled. The most promising uraniferous bodies are intimately related to intersecttions between the ductile ENE-trending faults and the brittle conjugate R' faults postdating the shearing event. The concentration of uranium at fault intersections rather than along individual faults suggests that these zones that are dilatational in nature were also highly permeable and therefore the hydrothermal fluids ponded there could readily precipitate U therein. A two-stage albitization has altered the foliated granitic host rock and the second albitization that has overprinted the first one is more effective at fault intersections. Whole rock geochemistry was performed by using ICP-MS and ICP-AES respectively for major oxides, trace and REE. The U-bearing rock suite exhibits restricted range in SiO 2 concentration (62.89% -70.91%) and Al 2 O 3 (13.16% -18.59%) and it is poor in MgO (0.02% -1.03%), CaO (0.24% -1.88%) and K 2 O (0.08% -5.32%). The mineralized rocks are however comparatively richer in Na 2 O (4.33% -10.92%) compared to their barren counterparts. The host granite and associated granodioritic rocks in the area are weakly metaluminous, peralkaline, and are calc-alkaline. They are moderately to strongly fractionated and have tholeiitic and shoshonitic affinities with moderate to high HFSE (high field strength elements) and LILE (large ion lithophile elements) enrichment. The Rb/Sr, Rb/Ba and Sr/Ba ratios are 0.31, 0.14 and 1.48, respectively. U content in the mineralized granite is up to 651 ppm while the non-mineralized rock has only 2.4 ppm U. The REE patterns of the granite show LREE enrichment and strong Eu negative anomalies (Eu/Eu* = 0.03 to 0.48). The main mineralization stage characterized by local U, Na, Pb, Zn, Ga, Hf, Sr, Fe, Al, P and Zr enrichments is related to the second albitization event and could probably be associated in time with the calcite-uranium stage. The identification of fault segments favorable for uranium mineralization in northern Cameroon (Poli area) is important for understanding the genesis of hydrothermal ore deposits within continental strike-slip faults and therefore has great implications for exploration strategies.

The core of detrital zircons from the southern Meiganga gold-bearing placers were analyzed by Laser Ablation Split Stream analytical techniques to determine their trace element abundances and U-Pb ages. The obtained data were used to characterize each grain, determine its formation condition, and try to trace the provenance. The Hf (5980 to 12,010 ppm), Y (27–1650 ppm), U (25–954 ppm), Th (8–674 ppm), Ti (2–256 ppm), Ta, Nb, and Sr (mainly <5 ppm), Th/U (0.06–2.35), Ti zircon temperature (617–1180 °C), ∑REE (total rare earth element) (98–1030 ppm), and Eu/Eu* (0.03 to <1.35) are predominant values for igneous crustal-derived zircons, with very few from mantle sources and of metamorphic origin. Crustal igneous zircons are mainly inherited grains crystallized in granitic magmas (with some charnockitic and tonalitic affinities) and a few from syenitic melts. Mantle zircons were crystallized in trace element depleted mantle source magmatic intrusion during crustal opening. Metamorphic zircons grown in sub-solidus solution in equilibrium with garnet “syn-metamorphic zircons” and in equilibrium with anatectic melts “anatectic zircons” during crustal tectono-metamorphic events. The U-Pb (3671 ± 23–612 ± 11 Ma) ages distinguish: Eoarchean to Neoproterozoic igneous zircons; Neoarchean to Mid Paleoproterozoic anatectic zircons; and Late Neoproterozoic syn-metamorphic grains. The Mesoarchean to Middle Paleoproterozoic igneous zircons are probably inherited from pyroxene-amphibole-bearing gneiss (TTGs composition) and amphibole-biotite gneiss, whose features are similar to those of the granites, granodiorites, TTG, and charnockites found in the Congo Craton, south Cameroon. The youngest igneous zircons could be grains eroded from Pan-African intrusion(s) found locally. Anatectic and syn-metamorphic zircons could have originated from amphibole-biotite gneiss underlying the zircon-gold bearing placers and from locally found migmatized rocks that are from the Cameroon mobile belt, which could be used as proxies for tracking gold.

Trace element concentrations and U-Pb ages were obtained using Laser Ablation Split Stream Method from the core of 115 zircon grains from the western Meiganga gold placer deposit. The data was used to characterize zircon, to understand the history of crystallization and to locate source rocks within the local and regional geological settings. Zircon trace element geochemistry was used to distinguish between magmatic and metamorphic affinity. The magmatic zircons have characteristics compatible with their probable origin from granitoid, syenite, tonalite, charnockite and mafic to ultramafic rocks. The metamorphic zircons composition is compatible with growth from anatectic melts and by sub-solidus crystallization in equilibrium with garnet. The zircon ages reveal Archean, Paleoproterozoic, Mesoproterozic, and Neoproterozoic events with the principal source could mainly belong to Paleoproterozoic magmatic lineage. Some of the Paleoproterozoic magmatic zircons were probably sourced from two mica granite found within the local geology, whereas the remaining zircons have features indicating source rocks within the Congo Craton. We suggest that the geologic history of these zircons is related to crustal-scale magmatic and/or tectono-metamorphic events, possibly linked to Eburnean and Pan-African orogeny.

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Syenitic and mafic rocks in Mindif Complex (Far North of Cameroon) were surveyed and characterized to classify them, understand their formation history, and assess their economic interest. Syenitic bodies (hololeucocratic microsyenites; mesocratic aplitic quartz-syenite; leucocratic porphyritic quartz-biotite syenite, and leucocratic porphyritic biotite-syenite) are silica-oversaturated to silica-saturated, alkaline, and metaluminous. Hololeucocratic microsyenites are structural oriented rocks, cooled in shallow depth from low trace and REE dry residual alkaline melts. Mesocratic aplitic quartz-syenite also crystallized in shallow depth from a much Ba-rich less dry residual melt. Leucocratic porphyritic quartz-biotite and biotite syenitic stocks represent two different rock types cooled from hydrous-rich melts in deep seated environments. The Mindif syenites probably crystallized in crustal source magmas (with important alkali feldspar accumulation) from partial melting of pre-existing igneous protoliths. Medium to coarse-grained-peraluminous granite found at the edge of pink microsyenitic dykes (in contact with granite host), is probably a crystallized product from magmatic mixture between the intrusive syenitic melt and a melt from partial fusion of the granite host rock. Mafic igneous rocks in Mindif are peridotgabbro and gabbro with different characteristics. Peridotgabbro, alkaline, holomelanocratic, medium-grained and ultrabasic, is an REE and incompatible elements depleted rock crystallized in shallow depth from a more evolved mantle source magma with plagioclase accumulation. Tholeiitic gabbro, melanocratic, and also medium-grained, was

This study presents the ore texture, mineralogy and whole rock geochemistry of iron occurrence from the Edea North area located at the upper limit of the Nyong Unit, part of the Congo craton. This iron mineralization is of magnetite quartzite type enclosed by metamorphic rocks of the granulite facies. Two main facies have been identified over the study area including the banded and the massive facies. The mineralogical set of these facies is in majority represented by magnetite, quartz and pyroxene martite in addition to minor biotite, apatite, and amphibole. Magnetite presents as irregular and elongated minerals which can contain quartz inclusions of various shapes and sizes, as blasts clustering, around pyroxenes and isolated xenomorphic magnetite minerals in the silicate phases. Quartz varies from fine to coarse-grained and ribbon quartz. This indicates re-crystallization and deformation during metamorphism. Electron microprobe analysis on magnetite and martite show Fe 2 O 3 contents that vary between 96.11 and 99.76. Whole rock chemical data showed that Fe-contents are as high as 62.9 wt%. The SiO 2 content varies between 33.8 wt% and 51.2 wt%. Iron oxides and SiO 2 are negatively correlated. Moreover, the low positive correlations between Al 2 O 3 and HFSE, and LILE suggest a contribution of clastic materials in the protolith of studied materials. The samples show low contents of V, Cr, Ba, Zr with respect to igneous rocks. This may infer a sedimentary origin for the studied rocks; furthermore, these materials may have undergone hydrothermal alteration. The REE patterns re- 660veal enrichment in LREE compared to HREE. Some samples show positive Eu (1.82) and other negative anomalies Eu (0.54 to 0.97). The lack of Ce anomalies suggests that the depositional environment of the Edea North iron occurrence was anoxic or suboxic. Overall, the Edea North iron occurrence may have undergone significant input from hydrothermal sources with imprints of the clastic during its deposition.

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