The Galim-Legalgorou Au–Ag prospect in Northwestern Cameroon has been recently classified as epithermal based on the wall-rock alteration assemblages, ore mineralogy, and chemistry of electrum plus sphalerite. However, questions regarding the host-rock compositions and how these may have interacted with mineralizing fluids remained unanswered. This study presents the host-rock compositions as well as features of quartz-hosted fluid inclusions related to mineralization. Whole-rock major element data show a highly evolved magmatic rock series from basalt to rhyolite, with the latter being the major host to the mineralization. Rare-earth element data of the trachyte and rhyolites show a slight enrichment trend in LREE relative to HREE, with a negative europium anomaly (Eu/Eu*CN = 0.09 to 0.51), suggestive of plagioclase fractionation at the magma source. Coexisting liquid-rich and vapor-rich secondary fluid inclusions are consistent with boiling and vapor loss during the late stages of fluid evolution. LA-ICP-MS data show that Na and K are the dominant ions in fluid inclusions, suggesting that the fluid was in equilibrium with alkali-rich host rocks at the time of mineralization. Homogenization temperatures of 180–303 °C (average 273 °C), with salinities around 2.2 wt

Dimension stone exploration in crystalline basement terrains requires spatially explicit methods that integrate geological potential with environmental, infrastructural, and regulatory constraints. This study develops a GIS-based multi-criteria decision analysis (MCDA) framework combined with Analytic Hierarchy Process (AHP) weighting to evaluate quarry suitability in the West Region of Cameroon. Geological, environmental, topographic and infrastructural criteria were integrated using GIS-AHP to generate a regional quarry suitability model. An additional methodological contribution is the introduction of a suitability density metric, which transforms pixel-based suitability outputs into administrative-unit indicators, enabling interpretation of quarry potential in relation to governance and planning units. This allows identification where suitable rocks occur and where they are spatially concentrated within communes and divisions. Results show that high and very high suitability zones are concentrated in the central-eastern crystalline belt, controlled primarily by granitoid-orthogneiss lithologies, moderate terrain conditions, and reduced environmental constraints. Sensitivity analysis indicates that the spatial pattern is robust under ± 20

The West Region of Cameroon, underlain by granitic and gneissic basement of the Central African Fold Belt, hosts significant dimension stone (DS) potential but remains weakly integrated into national efforts to increase the mining sector’s contribution to development. This study develops a transferable, reconnaissance‑stage, DS‑specific Geographic Information System-Analytic Hierarchy Process (GIS - AHP) framework for quarry - site screening in Precambrian basement terrains and applies it to the West Region as an under‑mapped Pan‑African testbed. Nine criteria grouped into geological (lithology, distance to major faults), environmental (protected areas, land use/land cover, distance to streams), topographic (relative relief, slope) and infrastructural (distance to roads, distance to built‑up areas) domains were standardized, weighted using AHP with acceptable consistency and integrated through weighted overlay analysis. The resulting map delineates four suitability classes, with 43.1% of the Region falling in high to very‑high suitability and extremely suitable zones restricted to 0.8% of the area, forming coherent belts mainly in the central and eastern sectors. To move beyond conventional pixel‑scale suitability maps, we introduce an administrative‑unit suitability‑density metric that quantifies the internal concentration of high‑ranked classes within divisions and communes, highlighting a subset of communes in Noun and neighbouring divisions as priority corridors for field validation, structural characterization and impact assessment. The framework illustrates how DS‑tailored GIS-AHP screening, coupled with suitability‑density analysis, can support conflict‑aware permit pre‑screening, integration of quarry planning into land‑use instruments and strategic positioning of dimension stone as a development mineral in Cameroon and comparable Pan‑African and Brasiliano basement provinces.

The Monoun Maar Volcano (MMV), located on the Cameroon Volcanic Line (CVL), is a small-volume polygenetic volcano characterized by eruptive activity and interaction with CO 2 -rich fluids. This study presents a revised tephrostratigraphy of the MMV, integrated with grain-size and componentry analyses, to reconstruct its eruption sequence, tephra emplacement mechanisms, and cratering processes. The MMV forms a complex, sigmoidal tephra ring surrounding a 0.62 km 2 maar. Seven stratigraphic units record a multi-phase eruptive history. Activity began with emplacement of a pyroclastic surge (U1), followed by oxidized scoria-fall deposits (U2) and a lava flow (U3). After a repose interval, eruptive loci migrated and produced a surge-dominated sequence with siderite-coated clasts (U4), followed by a lithic-rich tuff breccia (U5), a fresh scoria-fall deposit (U6), and a final surge sequence (U7). Grain-size data from unconsolidated beds analysed from Units 4 to 7 indicate polymodal distributions between − 4.3ϕ and 3.6ϕ, poor to very poor sorting, and median diameters ranging from − 2ϕ to -1ϕ. Componentry data show average proportions of 19.4 vol.% lithic clasts, 21.4 vol.% fresh juvenile clasts, and 59.2 vol.% recycled juvenile clasts. Stratigraphic relationships, sedimentary structures, and componentry variations indicate a two-stage evolution of the MMV. The first stage corresponds to emplacement of Units 1–3 and construction of the western sector of the crater system. The second stage involved renewed activity in the central and eastern sectors, as reflected by a paleosol, angular discontinuities, and the emplacement of Units 4–7 in the south-eastern and south-western sectors. The irregular sigmoidal morphology of the maar, together with paleosols, angular discontinuities, and three eruptive basins of variable depth, indicates prolonged vertical and lateral migration of the eruption loci, producing an amalgamated crater complex. A conceptual model based on fluctuations in fresh juvenile content suggests that changes in explosion loci were the principal control on temporal variations in eruptive style during Group II activity. Within this sequence, Unit 6 records the most juvenile-rich and dominantly magmatic phase, whereas Unit 4 records the least juvenile-rich and most excavational phase.

To constrain the petrogenesis of silicic magma along the Cameroon Volcanic Line (CVL), zircon chemistry is combined with U-Pb ages from two rhyolite samples obtained from Tertiary lithostratigraphic strata separated by a basaltic unit in the Sabga area. Ti in zircon temperatures for both rhyolites mostly vary from 636 -770 degrees C and 644 -779 degrees C for samples CMR01 and CMR02, respectively. Calculated oxygen fugacity values are below the quartz-fayalite-magnetite buffer (log fO2 = -14.5 to -10.8 for CMR01 and -14.2 to - 9.3 for CMR02). The inherited zircon from both samples yielded temperatures values ranging from 654 to 738 degrees C with a corresponding log fO2 between -12.0 to -16.2. These data suggest that both rhyolites share a common, strongly reduced deep crustal source but experienced minor, short-lived thermal variations associated with the separating basaltic unit. The evolution of magma through open-system fractional crystallization coupled with formation of REE-rich accessory minerals occurring concurrently is indicated by REE patterns and systematic co-variation between hafnium and trace element ratios (e.g., Hf vs. Th/U, Hf vs. Sm/Yb, and Hf vs. U). Epsilon Hf values for Tertiary zircon vary from -10.6 to 6.8 and also reveal Mesoproterozoic and Silurian mantle model ages (TDM) between 1144 and 440 Ma. Lu-Hf data disclose mixing between magmas from a juvenile mantle source and Palaeoproterozoic-Neoproterozoic basement rocks with TDM of 2511- 944 Ma.

This study characterizes quartz veins within the Bétaré Oya gold district (BOGD), Lom Basin, eastern Cameroon, focusing on field occurrence, mineralogy, textural varieties, and pyrite chemistry. Quartz veins, hosted by mica schist, display auriferous and barren categories with textures including smoky, vuggy, brecciated, and bulk types. These veins occur primarily within weathered mica schist and display two principal vein orientations: NE–SW (major) and ENE–WSW (secondary), with minor NW–SE and NNW–SSE components. Auriferous veins are oriented NE–SW and ENE–WSW trends, mirroring the host schistosity, and barren veins show NE–SW predominance with additional ENE–WSW and NNW–SSE components. This structural arrangement indicates a tectonically controlled, multi-phase hydrothermal system driving gold mineralization, with both visible gold and invisible gold hosted in pyrite. EMPA and EDS data show trace Au in pyrite alongside As, Co, Ni, and other metals. Mineralization styles are largely governed by hydrothermal fluid activity and the development of alteration halos (silicification, sericitization, hematization), both of which are structurally controlled by regional shear zones related to Pan-African tectonic processes. The results suggest a multi-stage, structurally controlled hydrothermal system where gold deposition occurred under evolving redox conditions, aided by ilmenite and magnetite hosts, making trace elements in pyrite useful vectors for exploration. Cette étude caractérise les filons de quartz dans le district aurifère de Bétaré Oya (BOGD), bassin de Lom, dans l’est du Cameroun, en se concentrant sur leur occurrence sur le terrain, la minéralogie, les variétés texturales et la chimie de la pyrite. Les filons de quartz, encaissés dans des micaschistes, présentent des catégories aurifères et stériles avec des textures incluant les types fumés, vacuolaires, bréchiques et massifs. Ces filons se trouvent principalement dans les micaschistes altérés et présentent deux orientations principales : NE–SO (majeure) et ENE–OSO (secondaire), avec des composantes mineures NO–SE et NNO–SSE. Les filons aurifères sont orientés selon les directions NE–SO et ENE–OSO, reflétant la schistosité de la roche hôte, tandis que les filons stériles montrent une prédominance NE–SO avec des composantes supplémentaires ENE–OSO et NNW–SSE. Cet arrangement structural indique un système hydrothermal multiphasé contrôlé tectoniquement, qui pilote la minéralisation aurifère, avec de l’or visible et de l’or invisible hébergé dans la pyrite. Les données EMPA et EDS montrent des traces d’Au dans la pyrite aux côtés d’As, Co, Ni et d’autres métaux. Les styles de minéralisation sont largement gouvernés par l’activité des fluides hydrothermaux et le développement d’auréoles d’altération (silicification, séricitisation, hématisation), lesquelles sont toutes deux contrôlées structuralement par des zones de cisaillement régionales liées aux processus tectoniques panafricains. Les résultats suggèrent un système hydrothermal multiphasé et contrôlé structuralement où le dépôt de l’or s’est produit sous des conditions redox évolutives, aidé par des hôtes d’ilménite et de magnétite, rendant les éléments traces dans la pyrite utiles comme vecteurs pour l’exploration.

Enigmatic shear zone-related mega quartz-magnetite veins, hosted by Neoproterozoic granitoids of the Central African Fold Belt (CAFB) in Mayo Binka, western Cameroon, are investigated using new field, ore microscopy, bulk-rock geochemistry, and magnetite microchemical datasets to elucidate their origin and deposit type. Magnetite is paragenetically the earliest Fe-oxide phase in the Mayo Binka prospect. Its partial replacement by mechanically twinned specular hematite and martite, along with ilmenite exsolution textures, indicates hydrothermal processes. The magnetite ores are characterized by high Fe2O3 ( 81 wt

Pressure and temperature conditions and electron microprobe analysis dating on monazite were conducted to investigate the age of the tectono-metamorphic events of Nyong Complex. The purpose of this work is to constrain P-T conditions and age to provide criteria for geodynamic models. The study area is made up of Paleoproterozoic metabasites, restricted Pan-African metasedimentary rocks and the rocks resulting from the melting of igneous rocks. This region displays a complex tectono-metamorphic evolution characterized by three phases of metamorphism associated with three deformational phases: The pre-D1 phase (HP-HT: 784–860 °C, 12–13 kbar) implying its relationship with Archean. The D1 phase (850 and 900 °C, 11–13 kbar) is a Paleoproterozoic event (1734 and 1893 Ma) that was developed under granulite facies metamorphic, implying that charnockitization took place in Paleoproterozoic. Charnockitization is a metamorphic process that transforms granitic rock into charnockite. The last stage D2 (450–500 °C, 7–9 kbar) is Pan-African in age (577–677 Ma) and characterizes the amphibolite facies metamorphism (MP-MT). This implies that the deformation regimes initiated in Paleoproterozoic continue to Neoproterozoic. Paleoproterozoic ages and metamorphic conditions have similarity with those obtained in Ogooué Series (Gabon) and Transamazonian belt (NE Brazil), suggesting the correlation of the Nyong Series with the Ogooué metamorphic domain and the Transamazonian belt. The deformational structures are relevant to a part of a North-South collisional chain and open a debate about the Nyong Series’tectonic affinity. The regional significance of this study imply that the vast portions of Archaean materials have reworked under high-grade conditions during the Paleoproterozoic orogeny.

Lake Monoun (LM) is a maar volcano located on the Cameroon Volcanic Line in West-Central Africa. In 1984, a limnic eruption occurred at LM, releasing large amounts of magmatic CO2 gas that had accumulated in the lake. The CO2 gas asphyxiated 37 people in the surrounding area. Despite this hazard, the volcanic history of LM maar remains unknown. This study presents the first comprehensive results of lithostratigraphy, physical volcanology, 14C dating and petrology of LM eruptive products. The lake has a WSW-ENE-aligned morphology with three main craters, the walls of which expose tephra and lava that can be divided into 5 stratigraphic units (A, B, C, D, and E from bottom to top). Unit A, a pyroclastic surge deposit in the NW, was produced by a phreatomagmatic eruption and deposited on a thick (ca.170 cm) paleosol developed on granitic basement. The paleosol yields a 14C age of ca 1.3 cal. ka. Units B (weathered scoria fall) and C (lava flow) in the NW part of the lake were respectively produced by strombolian and effusive eruptive activities. The SE side consists of unit D (scoria fall) a product of violent strombolian activity and unit E (voluminous surge) deposited by phreatomagmatic activity. The surge deposits of units A and E are rich in lithic fragments such as granite and lava, indicating subterranean excavation of country (accidental) and volcanic (accessory) rocks. A short time break represented by thin (ca. 15 cm, 0.1-0.3 cal. ka) paleosol can be recognized between units A and E in the distal facies. Based on the temporal and spatial distribution of these deposits, the eruption history of LM can be grouped into two stages. The first stage led to the development of the western and central craters and is recorded by units A to C in the NE section. The second stage proceeded after a short hiatus represented by the thin paleosol and a shift of the eruptive locus to the SE part of the lake. This gave rise to the largest eastern crater characterized by well-preserved units D and E. The LM case study reveals a potential time-space evolutionary pathway for crater formation, implying a polygenetic origin. Juvenile materials from the units are basanitic in composition with narrow chemical variation, suggesting a common magma system through the two stages. Silica content gradually increases from units A to E (SiO2 = 43.4 to 45.8 wt%), suggesting that the magma was differentiated with time (from units A to E) and

The Etam granite-gneissic complex is located in western part of the Tombel graben in the Central African Fold Belt in Cameroon. It includes plutonic rocks (coarse-grained granite, fine-grained granite and biotite granite) partially mylonitised and a metamorphic basement constituting gneiss and migmatites. Granites are syn- to post-tectonic and S-type, ferroan and strongly peraluminous. The high Rb/Sr (0.92–1.46) and low Sr/Ba (0.18–0.26) ratios coupled with an important negative Eu (Eu/Eu* = 0.37–0.59) anomaly characterize the lower degrees of crustal melting upon their formation accompanied with the dehydration of hydrous minerals as biotite. A CaO/Na2O ratio greater than 0.3 indicates that granites from Etam were derived from clay-poor, plagioclase-rich psammitic source material. Etam granites are peraluminous and display high potassic and alkali content. These characteristics are in line with the continental collision setting. The evidence of heterogeneous deformation in these rocks suggest syn to late collisional setting. The estimated crystallization temperature is resolved to be between 750 and 875 °C for Etam granites. Mylonites exhibit granitic composition with high SiO2 and Al2O3 contents similar to granites. Coarse-grained granite and mylonites show only little changes in magmatic minerals content. However, the grain size varies, decreasing from the coarse-grained granite to mylonite. The gneiss and mylonite plot in the igneous field in discrimination diagram. These characters suggest the igneous protoliths that are probably the surrounding coarse-grained granite for mylonite and an earlier intrusion for gneiss.

The Cretaceous Koum Basin is a rift-related half-graben in northern Cameroon, which constitutes a portion of the Yola Arm of the Upper Benue Trough. This study presents the first comprehensive dataset combining mineralogical, bulk-rock geochemical, and stable C–H–O isotopic data for dark-gray, fine-grained mudstones from the basin, providing new insights into its sediment source, paleoenvironment, and geodynamic setting. The mudstones primarily consist of phyllosilicates ( 8.6

In order to determine the nature of the original chemical precipitate and the ocean during the emplacement of BIF in the northern part of the Congo Craton data from the Njweng prospect anomaly was utilized. During field mapping and ground-truthing of this anomaly, samples were collected and the geochemical data of 26 representative samples constitute the core of this contribution. The selected samples for geochemical studies represented the various facies: oxide facies BIF composing of magnetite, hematite/martite, quartz; the silicate facies BIF composing of quartz, magnetite, hematite/martite and goethite. The ore (≥75 wt.% Fe) is a hematite-martite-goethite assemblage. The BIF show a characteristic banding and no association with volcanic activity. Chemical analysis was accomplished using a combination of the Inductively Coupled Plasma Emission Spectrometry (ICP-ES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) on the major and trace elements respectively. The BIF have Fe2O3(T) content that ranges from 47.2 to 88.5 wt% and SiO2 from 1.87 to 49.28 wt% with the low silica content in the ore. The BIF show average SiO2 content of 41.20 wt% and 53.9 wt% Fe2O3. Both the oxide and silicate facies BIF samples show modern seawater characteristics (depletion in LREEY relative to HREEY, positive Eu(Eu/Eu*), Y anomalies and super chondritic Y/Ho ratios). The BIF reveals low Al2O3, TiO2, Na2O, K2O, HFSE and Nd concentrations. The average concentration of V, Ni, and Cu in the BIF is low.

Urban wetlands in sub-Saharan Africa face increasing pressure from rapid urbanization, yet the geochemical and mineralogical characterization of their sediments crucial for environmental assessment, monitoring, and sustainable management remains limited. This study investigates the recent sediment layers of the Mfoundi floodplain, a heavily urbanized wetland in Yaoundé, Cameroon, to determine their mineralogical and geochemical composition, provenance, and environmental implications. Nine sediment pits, excavated to depths of up to 2 m, were logged and sampled for granulometric, mineralogical (XRD and Raman spectroscopy), and geochemical (XRF and ICP-MS) analyses. The sediments are predominantly sandy to silty sand, with a heavy mineral assemblage comprising zircon, tourmaline, rutile, and kyanite, reflecting derivation from proximal metamorphic basement rocks, including gneisses, quartzites, and migmatites. The bulk geochemical data show high SiO2, and low concentrations of major and trace elements, consistent with quartz-rich, compositionally mature sediments. The sediments display overall depletion in trace elements and rare earth elements (REEs) relative to the upper continental crust (UCC), attributed to intense chemical weathering, quartz dilution, and low retention in sandy textures. High Chemical Index of Alteration (CIA: 50–98.92

Heavy minerals in stream sediment play a vital role in provenance studies and mineral prospection campaigns. Seventeen stream sediments and six pit samples were obtained from the Ekomedion uranium–molybdenum prospect and evaluated for their heavy mineral content. The mineralogical assemblage includes zircon, rutile, tourmaline, garnet, ilmenite, chlorite, micas, and kyanite; ultra-stable minerals are the most abundant. This mineral assemblage revealed a great diagnostic of the catchment geology that is observed to be deeply weathered in the field. Geochemical signatures for representative ilmenite megacrysts were obtained and analyzed. Measured TiO2 concentrations range from 27.00 to 60.92 wt.

Due to an increasing interest in mineral prospection, Manjo granites which are orogenic have been studied in terms of the geochemistry of whole rock and isotopes of interest found in the associated zircons. This was done to define and situate these rock unit within the context of the regional belt that is Pan African in age, establish the source of Manjo granites and their evolution during the Pan-African orogeny. More so, this study sheds more light on the controversy around the orogenic statues of granites in this section of the geological region, examines their potential for hosting molybdenum, establishes their link with other rocks within this part of the region and how they relate to the Mo-U-bearing biotite-granite in its Ekomedion neighborhood. Sixty-six zircon grains gotten from the granites and their trace elements and Lu-Hf isotopic signatures were examined. The zircon grains' ages were gotten by mass spectrometric method using the U-Pb systematics by laser ablation.The zircons ratios of U to Th varry between 0.2-2.3 relating to sources that are originally magmatic and totally different from those related to souces related to hydrothermalism and metamorphism. The granites were emplaced within the 585 +/- 17-616 +/- 12 Ma age bracket. Zircons in this study similar to the nearby Ekomedion U-Mo-bearing two mica granites and other felsic massifs found within the shear zones of central Africa (CASC)point to the fact that the Manjo granites were formed at low oxygen fugacity (log & fnof;O-2; -15.848 to -4.515, and log & fnof;O-2@FMQ; -17.409 to -3.677). More so, samples plot mainly outside the defined fertile fields on plots of Eu/Eu* Vs (Ce/Nd)/Y, 10000 x (Eu/Eu*)/Y Vs (Ce/Nd)/Y and Eu/Eu* Vs Dy/Yb. The above points support dominantly plagioclase fractionation in a reduced and less hydrous melt system pointing to a low Mo fertility potential of this pluton emplaced at an average Ti-in-zircon temperature of 861 +/- 56 degrees C. The apparent epsilon Hf(t) values for CMR-01 zircon grains range between -15.84 and -1.45 and apparent epsilon Hf-(t) values for CMR-02 zircon grains vary from -25.02 to -12.39. On spidergraphs, the grainites are depleted in HREE and enriched in LREE . These plots together with epsilon Hf-(t) values and other indications point to the fact that the granites were derived through partial melting of quartzo-feldspathic crustal magmatic sources. More so, the data showing a new age here show clear signs of post collisional Pan-African magmatism at similar to 585 +/- 17 Ma in the context of a pre-drift Gondwana evolution.

Banded Iron Formations (BIFs) interbedded with schists characterize the Mbarga prospect in the Ntem Complex at the northwest edge of the Congo Craton. This study presents new whole-rock geochemical, Sr-Nd, and zircon U-Pb isotopic data for the BIFs and schists to constrain the timing and geodynamic setting of the deposit. The abundances of SiO2 (52.81 to 79.14 wt%) and Na2O+K2O (4.24 to 8.54 wt%) in the schists indicate andesitic, dacitic, to rhyolitic protoliths. Trace element signatures, such as high Ba and depleted Nb-Ta concentrations, suggest a volcanic arc affinity. A well-defined U-Pb zircon age of 2890 +/- 4 Ma implies a Mesoarchaean protolith age, while an imprecise Rb-Sr whole-rock age of ca. 2.65 Ga is consistent with known tectonothermal events ( 2.75 and 2.65 Ga) in the Ntem Complex. Initial epsilon Nd(2.89) values of + 0.8 to + 2.0 for the schists indicate an unevolved, mantle-like source for the protoliths. The BIFs show partial to extensive alterations of magnetite to hematite-martite and are of the Algoma type. They are characterized by high Fe2O3 ( 54.06 wt%) and SiO2 ( 45.40 wt%) but low Al2O3 ( 0.14 wt%), TiO2 ( 0.1 wt%), Zr ( 4.92 ppm), Th ( 0.11 ppm), and REE-Y contents. Rare earth patterns marked by LREE depletion, positive Eu anomalies ( 2), mild Ce depletion (Ce/ Ce* 0.67 to 1.16), and super-chondritic Y/Ho ratios ( 34) suggest formation under anoxic to suboxic Archaean marine conditions, possibly involving mixing of Archaean seawater with minor (0.1-1 %) contributions from medium- to high-T hydrothermal fluids. Sparse 2951 +/- 24 Ma zircons, presumably of detrital origin, establish a depositional link to the associated schists, redefining the age of BIF deposition within the Ntem Complex to ca. 2.95-2.89 Ga. However, whole-rock Sm-Nd isotope data for five BIF samples define a scattered array with an imprecise slope equivalent to an age near 1004 +/- 78 Ma, which may reflect a previously unrecognized recrystallization event in the BIFs. The initial epsilon Nd of this array (-11.1 +/- 2.0) suggests a crustal source. The mineralogical, geochemical, and isotopic datasets reconcile the Mbarga BIF prospect with arc magmatism in the Late Archaean, suggesting their formation in a back-arc basin setting.

Galim-Legalgorou, located on the Cameroon volcanic line, is now known to host significant epithermal Au-Ag mineralization, likely of the low sulfidation type. Although ore mineralogy and microchemistry of electrum and sphalerite have largely demonstrated this claim, questions regarding the fluid sources and physico-chemical conditions at mineralization remained unanswered. This study presents the major fluid inclusion features (petrography, microthermometry, composition) and attempts an explanation of their bearing on the origin and evolution of the mineralization. Secondary assemblages with co-existing liquid and vapor inclusions suggest that a vapor phase existed at mineralization, and may have been triggered by hydrothermal explosions leading to hydrofracturing and brecciation. All fluid inclusions are two-phase aqueous solutions with low average salinities (2.2 wt% NaCleqv), and homogenization temperatures ranging from 176 - 303 C-0 (av. 263 C-0), typical of conditions in epithermal systems. A negative correlation is observed between homogenization temperatures and fluid salinities indicating a volatile-free fluid boiling process that excludes fluid mixing as a principal trigger of mineralization. Inclusion composition shows that Na and K are the dominant ions in solution, suggesting that the fluid was in equilibrium with Na- and K-rich rocks and minerals. These data further support the claim of an epithermal mineralization at Galim-Legalgorou.

The Mbarga itabirite deposit in the Mbalam iron district on the northwest edge of the Congo Craton (CC) hosts two main types of iron ore enrichments: supergene and specularite ores. This study presents mineralogical, geochemical, and isotopic datasets on these ores to determine their genesis. Ore microscopic studies indicate that the itabirites are of the oxide facies type, with magnetite showing partial to extensive alteration to hematite-martite. The supergene ores consist of hematite + martite + goethite +/- gibbsite +/- magnetite +/- quartz, while the specularite ores are mainly composed of hematite + martite +/- quartz. Magnetite microchemistry suggests formation under low-T hydrothermal conditions (similar to 200-300 degrees C) with high fO(2). Geochemical analyses show that the supergene and specularite ores have higher Fe2O3 (88.27 to similar to 100 wt%) and lower SiO2 (<0.01 to 0.18 wt%) contents than the itabirites (31.95 wt% Fe2O3, 67.16 wt% SiO2). The enrichment of Fe in the supergene ores is attributed to the depletion of major oxides and trace elements due to weathering and supergene enrichment, while the high Fe content in the specularite ores stems from the precipitation of iron-rich, but trace- and rare earth elements (REE)-deficient hydrothermal fluids. The slightly higher Al2O3 content and positive Ce anomalies in the supergene ores suggest the retention of Al-bearing minerals (gibbsite) and reveal highly oxidative conditions during martitization. Stable isotope analyses reveal that the supergene and specularite ores have delta O-18 values of -2.5 to -0.3 parts per thousand and - 2.0 to -3.4 parts per thousand, and delta H-2 values of -75 to -123 parts per thousand and - 70 to -119 parts per thousand, respectively, suggesting the involvement of isotopically light-evolved meteoric water in their formation. In contrast, the itabirites exhibit heavier delta O-18 (8.5 to 10.2 parts per thousand) and delta H-2 (-85 to -91 parts per thousand) values, suggesting formation from mixed magmatic and metamorphic fluid sources. A "polygenic-supergene-hydrothermal" model is suggested for the formation of the Mbarga itabirite-hosted iron ores.

Local populations in Cameroon thrive on forest resources and the flow of ecosystem services they provide are pivotal in sustaining national economy, improving people's lives, safeguarding biodiversity, and mitigating the impacts of environmental changes. The exploitation of these resources invariably leads to deforestation and forest degradation. This study was designed to evaluate land use land cover change (LULCC) in the Eseka alluvial gold mining district with the aid of Landsat images. In the investigation of forest cover change, four Landsat satellite images for (1990, 2002, 2015 and 2022) were used. Ground-truthing also helped to identify the activities carried out by the local population and to determine agents, drivers and pressures of land use and land cover change. Four main land cover classes namely: forest, agricultural land, settlement/mining camps and water bodies were selected. Between 1990 and 2022, the proportion of forest decreased from 98% to 34% while those of agricultural land and settlement/mining camps increased from 2% to 60% and 0.54% to 6% respectively. Analysis showed ongoing deforestation with forest cover loss of ~98,263 ha in 32 years giving a cover change percentage of 63.94%. Kappa coefficient for the study period ranged from 0.92 to 0.99. Forest cover loss could be attributed to farming activities, wood extraction and alluvial gold mining activities. Economic motives notably the need to increase household income from a frequent demand for farm and wood products in neighbouring towns and the quest for gold were the main drivers of these activities. Hence, this study assesses the impact of human activities from the mining sector on the forest ecosystem in a bid to inform mitigation policies.