Comparative Insights into Banded Iron Formations of Ivory Coast and Guinea

 Corresponding author: Mohamed Samuel Moriah Conté Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Comparative Insights into Banded Iron Formations of Ivory Coast and Guinea Mohamed Samuel Moriah Conté 1, *, N’Guessan Nestor Housou 2, Mohamed Lamine Timité 1, Alain Nicaise Kouamelan 2, Yao Théodore Koffi 2, Adingra Martial Pohn Koffi 2 and Youan Ludovic Irié Bi 2 1 Applied Research Laboratory in Geosciences and Environment, Fundamental Geology and Prospecting Research Unit (URGFP), Department of Geological Services, Higher Institute of Mines and Geology of Boké, BP : 84-Boké, Republic of Guinea 2 Laboratory of Geology, Mineral and Energy Resources, Faculty of Earth Sciences and Mining Resources, Félix Houphouët Boigny University, Abidjan, Ivory Coast. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 Publication history: Received on 09 October 2025; revised on 17 November 2025; accepted on 19 November 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.28.2.3865 Abstract The Banded Iron Formation (BIF) is part of the Precambrian history. They are well studied in several provinces of the world: Harmesley range (Australia), Transvaal (South Africa), Krivoy Rog (Ukraine), Labrador (Canada), Lake Superior (USA), Gunflint and Biwabik (USA) and Isua (Greenland). They constitute a world-class economic reserve in Guinea and Ivory Coast, more particularly in the Nimba-Simandou-Klahoyo-Tia Mountains). The main BIF studied are located on the borders of these two countries. These BIF present close similarities in petrography, structural metallogeny and geochemistry. The metallographic study has shown that the mineralization is essentially composed of magnetite. Although they share some characteristics, they show some typical divergences in terms of metamorphism and age. The Mount Klahoyo and Tia BIF are of Archean Algoma type while those of Guinea are of Proterozoic age, characteristic of BIF of the Lake Superior type. Overall, most of the mineralization is contained in magnetite or itabirite quartzites (BIF). From this, we can deduce that the BIF of Guinea are a continuation of those identified in Ivory Coast. Keywords: Klahoyo; Nimba; Simandou; Guinea; Ivory Coast; BIF 1. Introduction Banded Iron Formations (BIFs) or BIFs are metamorphosed and laminated iron oxide formations in which cherts bands have been recrystallized into granular quartz, where iron is present as hematite, magnetite, and/or martite [1]. They are the most extensively studied of all iron formations, for several major reasons. Firstly, they are of great interest for their economic importance, as they are the world's largest source of iron ore [2]. Secondly, for their scientific importance, given their presumed role in the evolution of the oceans, the early atmosphere and the understanding of ancient geological systems [3]. Also iron ores (hematites, martites, goethites (≥56% Fe)) are the main source of iron for the world's steel industry. Finally, they constitute the main sulphide mineralized facies but also correspond to favourable traps for gold mineralization [4]. BIFs are the Earth's most important commercial source of iron ore, with some of the largest known deposits found around the Lake Superior region in the northern USA and Canada, in the Transvaal Basin in South Africa, in the Carajas Province in Brazil, and in the Hamersley Basin in Western Australia [5]. Sub-Saharan Africa is rich in iron deposits, with over 21 billion tonnes of iron ore in 1967. Ivory Coast contains huge reserves of iron deposits of economic interest, located in and around the Man region in the west. These iron formations are referred to as magnetite quartzites, the main ones being the Mont Klahoyo and Mont Tia deposits [6],[7],[8],[9],[10]. Similar iron formations (quartzites with magnetites) have also been identified in the Guinean part of the Nimba massif and the Simandou range [11],[12],[13],[14],[15],[16],[17]. For some researchers, these known iron formations in these World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1954 two countries appear to be identical, as they consist of magnetite quartzite (itabirite) or ferruginous quartzite (BIF), of Archean and Paleoproterozoic age according to [13],[18],[19],[20],[21]. Furthermore, [9] suggests that they differ in terms of stratigraphic arrangement of layers as well as age, yet no study has yet been carried out between the iron deposits of Ivory Coast and Guinea. In view of this, we feel it is necessary to improve our knowledge by carrying out a comparative study between the banded iron formations (BIF) of Ivory Coast and those of Guinea, in order to understand their characteristics. The overall aim is to summarize the ribboned iron formations of Ivory Coast and Guinea. 2. Geological context of Ivory Coast and Guinea 2.1. Geology of Ivory Coast * Figure 1 Simplified geological map of Ivory Coast [18] modified by [21] Ivory Coast belongs to the West African Craton, specifically to the Man Ridge (Fig.1). Geologically, it is covered by two groups: the Precambrian basement, which accounts for around 97.5% of the surface area, and the sedimentary basin, World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1955 which occupies 2.5% of the territory at the crescent-shaped southern end, stretching from Fresco to Axim (in Ghana) [22]. The Precambrian basement is made up of two major domains of different ages, separated by the Sassandra fault [23]: an Archean domain to the west, called the Kenema-Man domain, to which the study area belongs (Fig.1), and a Proterozoic domain to the east, called the Baoulé-Mossi domain. The Archean domain also covers the far west, a large part of Liberia, Guinea and the entire Serra Leone [21]. Geologically, it has been structured by two major orogenic cycles: the Leonian from 3.3 Ga to 3.0 Ga and the Liberian from 2.9 Ga to 2.7 Ga [18],[24],[25],[26],[27]. Petrographically, the Leonian domain is composed of four (4) lithological assemblages, namely magmatic grey gneisses and pink granulites, anatexites, ferriferous quartzites and intrusive charnockites. However, the Liberian domain is characterized by granulites, charnockites, migmatites, quartzites and amphibolo-pyroxenites [9]. 2.2. Geology of Guinea 1. highly metamorphosed rocks, 2. charnockites, 3. intrusive granitoids, 4. metagabbros, metapyroxenites and amphibolites. 5 metagabbros, metapyroxenites and amphibolites, 6. volcano-terrigenous deposits, 7. basite and ultrabasite intrusions, 8. dislocated and metamorphosed terrigenous and pyroclastic deposits, 9. orogenic granitoids, 10. tardiorogenic granitoids and migmatites, 11. postorogenic granitoids, 12.terrigenous deposits, 13. volcano-terrigenous deposits, 14. Acidic (a) and basic (b) intrusions, 15. continental molasse, 15. continental terrigenous deposits, 17. marine terrigenous-carbonate deposits, 19. terrigenous-carbonate deposits, 19. terrigenous deposits, 20. marine terrigenous-carbonate deposits 21. deltaic and littoral terrigenous deposits, Marine terrigenous deposits, 24. peridotite-gabbro intrusions (a), Sills and dolerite dykes, doleritic gabbros and dunites (b) , 25. main faults: subvertical (a), dipping (b) and inferred (c) Figure 2 Geological map of Guinea [19] Like Ivory Coast, Guinea lies on the West African Craton, more precisely at the Man ridge, in the south-western part of the craton. Its geological structure comprises three stages: i) the crystalline platform basement (craton), ii) a folded platform cover comprising two distinct units, and iii) a flat-lying sedimentary cover consisting of numerous intrusions of basic and ultrabasic composition, as well as bodies of kimberlites [19] (Fig.2). This crystalline basement comprises an Archean, early Proterozoic and Pan-African phase. According to Mamedov et al. (2010), the crystalline basement of World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1956 the bedrock is composed solely of Archean consolidation structures: Early Archean (lower) and Late Archean (upper). The study area in the N'zérékoré region belongs to the Archean domain (Kenema-Man), bounded to the west by the Todi shear zone and to the east by the Sassandra-Trou shear zone, which hosts the Simandou chain and the Pic de Fon deposit. Geologically, it is composed of BIF, metagabbros and orthogneisses of granitoid composition [19] and gneissic formations including the Guélématas gneisses (~ 3.5 Ga) [28]. 3. History of work on banded iron formations (BIF) in Ivory Coast and Guinea 3.1. Work carried out on banded iron formations in Ivory Coast A number of studies have been carried out on the iron deposits in and around Man (west of Ivory Coast). Bolgarsky was the first to explore these regions during five missions carried out between 1932 and 1945, highlighting several lithologies containing iron formations. Subsequently, [29], using samples collected by Bolgarsky in western Ivory Coast, carried out a detailed petrographic study of the Man region and surrounding area, revealing the presence of iron formations. Between 1960 and 1962, as part of a major BRGM mission, Carrive studied several massifs, including those of the Dan (Sipilou region), Toura, Baoubly-Kiriao chain and Touba region. His work revealed the most promising showings in the Baoubly-Kiriao chain (Mount Klahoyo iron deposit) and its extension towards Mount Gao. In 1962, Spindler, on the recommendation of BRGM, took up his predecessors' work in the Eburnian part of the Nimba Mountains and supplemented it with an in-depth study combining aerial magnetic prospecting, photogeological analysis and ground prospecting. He concludes that only the titaniferous magnetite lenses of the Dan Mountains massif and certain itabirites of the Nimba Mountains show significant concentrations of iron ore, while emphasizing the absence of highgrade deposits at either surface or depth in this area. [18], in his structural sketch of Ivory Coast, suggests that the ferruginous quartzites of western Ivory Coast are contemporaneous with those of the Simandou chain in Guinea. These formations, homogeneous and 150 to 400 meters thick, are interbedded, folded and recrystallized in amphibolite and sometimes granulite facies. [30] work on Mount Klahoyo identified eight stratigraphic units, of which only the oxidizedfacies magnetite-quartzite units constitute the most important ores in the deposit. Finally, [9], through his petrographic and geochronological study of Archean granulite assemblages and associated formations in the Man region, showed that magnetite quartzites share similarities with those described by [1], distinguishing two main deposit types: Mount Klahoyo and Mount Tia, whose magnetite quartzites are referred to as itabirites due to their mineralogical composition. [31] indicates that magnetite quartzites originate from fine sedimentation in a quiet environment, made possible by the reducing atmosphere of the Precambrian, which allowed the iron derived from alteration of the substratum to remain in the ferrous state and be transported in the form of soluble complexes to the sedimentary basins. According to [10], only magnetite quartzites, or itabirites, make up the bulk of the Mount Klahoyo iron deposit, these formations being associated with felsic migmatitic gneisses (FMGs) and amphibolo-pyroxenites. [32], following his study of the magnetite formations in the Danané-Biankouma region (Yepleu-Bounta sector), concludes that these formations have strong petrographic, metallographic and metamorphic similarities with the Klahoyo and Tia deposits, while differing in their mineralogical composition and the nature of their host rocks. The author suggests that these similarities testify to emplacement in the same geodynamic context and confirm the existence of a manganiferous province in western Ivory Coast, extending from the Man region to Biankouma. 3.2. Work on banded iron formations in Guinea The Republic of Guinea has significant mineral resources, including iron, aluminum, gold and diamonds, as well as other useful minerals such as nickel, uranium, titanium, copper, platinoids, chromium, corundum, graphite, talc, monazite and topaz. These riches have attracted the interest of numerous companies who have come to explore the country's main resources. [11] distinguish two lithotectonic units at the origin of the Nimba and Simandou mountains: one plutonic and the other volcano-sedimentary, separated by tectonic contacts, and conclude that they are lithologically and geochronologically similar. In 2009, a feasibility study carried out by BSG Resources Limited on the Zogota iron deposit revealed that it results from the lateritization of subvertical itabirite units forming the backbone of the Zogota ridge, considered to be the natural extension of the Simandou chain. [19], as part of a study commissioned by the Guinean Ministry of Mines and Geology, showed that the main iron showings are concentrated on the Simandou-Nimba ranges and their southern extension, while highlighting the main useful minerals in the Archean part of the territory, where iron is associated with the magnetite quartzites of the Kasila and Kambui series. [33] indicate that the itabirites of the Nimba and Yekepa region (Tokadeh-Gangra-Yeulliton) correspond to recrystallized iron oxide formations, composed mainly of quartz, magnetite and/or hematite, probably derived from the chemical alteration of upper metavolcanic rocks. Mamadou et al (2011) identified Late Archean and Early Paleoproterozoic ribboned itabirites (magnetite quartzites) on the Nimba and Simandou mountains. Finally, [13] distinguished two groups of rocks within the iron World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1957 formations of the Nimba range and its western extension: (i) magmatic and ortho-magmatic rocks (gneisses, granites, amphibolites and quartzites) of Archean age and (ii) Proterozoic rocks of metasedimentary origin. Their petrographic and metallogenic work revealed two types of banded iron formations: silicate (SIF) and oxidized (OIF), containing minerals such as magnetite, hematite, pyrite, goethite, martite and siderite, and dating from the Proterozoic. 4. Methodology Field petrography consisted in describing the lithological units observed on the various outcrops and drill cores. This description enabled rocks to be identified on the basis of several criteria, including texture, structure, mineralogical composition, color and lithological family. Representative samples were taken from various outcrops in Ivory Coast and Guinea. Thin sections prepared from these samples were used to determine the mineralogy of the rocks and specify their origin. The mineralogical assemblages observed complemented the macroscopic observations and helped refine the rock classification. Metallographic microscopy was also used to identify the various iron minerals present. Measurements of orientation (alpha and beta angles) and dips of primary and secondary structures were carried out on drill cores from Guinea, while in Ivory Coast, structural analysis was carried out directly on outcrops. The data obtained was then processed using Stereonet stereographic software, in order to interpret the various structures. Finally, major and trace elements were determined by X-ray fluorescence spectrometry (XRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES). 5. Results 5.1. Petrographic and structural data of Ivory Coast BIFs 5.1.1. Petrographic data The geology of Mount Klahoyo consists of magnetite-bearing quartzite (itabirite) hosted in a band of felsic migmatitic gneiss. The deposit is Archean in age, with reserves estimated at around 700 million tonnes (Mt), for 32.72% Fe [9]. In addition to this host rock, other formations associated with the magnetite quartzites include amphibolo-pyroxenite, garnet gneisses, garnet pyroxenites, granites and garnet hypersthenites [6],[9],[10],[30]. According to [9], the Mount Klahoyo and Tia deposits are lithologically similar. Magnetite quartzite It is the host rock of iron ores. It has a massive, gray to whitish-gray appearance. It is characterized by alternating light bands of quartz minerals and dark bands of iron oxides (magnetite or hematite and/or goethite or limonite) (Fig.3A). Microscopically, the rock has a bedded texture (Fig.3B and C), consisting mainly of quartz, iron oxides and pyroxene [9],[10]. Amphibolo-pyroxenites It is a massive, greenish-grey rock with an equant structure and minerals visible to the naked eye (Fig.4A). In places, it is associated bed by bed with quartzites [6],[9],[10]. Macroscopically, the minerals observed have a granoblastic texture (Fig.5B), composed in order of abundance of: amphibole, pyroxene, biotite, feldspars, orthoclase, opaque minerals and rarely quartz (Fig.4B;C and D). World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1958 Qtz: quartz, Pyx: pyroxene, Opq: opaque minerals. Figure 3 Macroscopic and microscopic appearance of magnetite quartzites [10]. (A). Macroscopic sample of magnetite quartzites; (B). Alternating light and dark beds at LN microscopy; (C). Alternating light and dark beds at LP microscope. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1959 Figure 4 Macroscopic and microscopic appearance of amphibolo-pyroxenite [10]. (A). Macroscopic sample of amphibolo-pyroxenite; (B). Pyroxene in association with plagioclase and quartz and (C). Pyroxene in association with amphiboles. Qtz: quartz, Pl: plagioclase, Amp: amphibole, Pyx: pyroxene, opq: opaque minerals Garnet gneiss It is a massive rock with a foliated structure consisting of alternating light and dark bands (Fig.5A). The light bands are rich in felsic minerals (quartz and feldspars) and the dark bands rich in ferromagnesian minerals (biotite and amphibole) [10]. Garnet crystals are scattered throughout the rock. Microscopically, it has a granolepidoblastic texture composed of: quartz, plagioclase, biotite, microcline, garnet, sericite, chlorite and opaque minerals [10]. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1960 Figure 5 Macroscopic and microscopic appearance of garnet gneiss [10].. (A). Macroscopic sample, (B). Microphotograph seen in LPNA. (C). Microphotograph seen in LPA showing the association of plagioclases with quartz, (D). LPA microphotograph. (E). Microphotograph seen in LPA rich in quartzo-feldspar. (F): Microphotograph seen in LPA with a muscovite phenocrystal Garnet granite It is a massive, leucocratic rock with a grainy texture (Fig.6). These minerals are visible to the naked eye. Microscopically, this rock has a grainy texture. It consists of quartz, biotite, feldspar and garnet crystals scattered throughout the rock. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1961 Figure 6 Macroscopic and microscopic appearance of garnet granite [10]. (A). Macroscopic appearance; (B). Microphotograph seen in LPA and (C). Microphotograph seen in LPNA. Qtz: quartz, Pl: plagioclase, Grt: garnet, Bt: biotite, Opq: opaque minerals Garnet hypersthenite It is a massive rock composed of quartz and hypersthene, to which garnet and traces of grünerite are added [6],[9]. It occurs within granulite gneisses and is finely associated with magnetite quartzites. Microscopically, it has a granoblastic texture. 5.1.2. Metallographic data Metallographic analysis was carried out mainly on quartzites with magnetites. The samples were taken from [10]. Observations were made on three polished sections: KM 05, KM 22 and KM 07. Microscopically, we highlighted two facies: the oxidized facies (magnetite and hematite) and the sulfide facies (pyrite and chalcopyrite) (Fig.7). Magnetite Magnetite is present on two slides (MK 07 and MK 22) analyzed (Fig.7A,D and F). It is the main iron ore in the magnetitebearing quartzites of Mount Klahoyo. It has a gray-brown hue and an automorphic form, with some subautomorphic to xenomorphic sections. It has low reflectivity. It appears on these two slides in association with hematite. Hematite It is mainly found on the MK 05, followed by the MK 07 blade (Fig.7D and F). It has a light gray to white hue and low reflectivity. It has an elongated shape and is always associated with magnetite. It is the second most iron-rich mineral after magnetite. Pyrite Pyrite is the most disseminated and abundant sulfide facies (Fig.7E). It accounts for some 80 to 85% of the sulfides present and comes in a variety of forms. It often occurs as rod and xenomorphs, disseminated or remobilized along the foliation plane in the host rock. These pyrite crystals are oriented in a well-defined direction. It has a yellowish hue. Chalcopyrite They are generally found in association with pyrite (Fig.7C and E). Chalcopyrite occurs as fine xenomorphic grains, sometimes elongated (Lame MK 07). Ilmenite Ilmenite (FeTiO3) or titanium-bearing iron occurs as a grey flake with brownish tips (Lame MK 07) (Fig.7E). World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1968 Figure 15 Microscopic appearance of Tokadeh orthogneiss and metagneiss. (A). Gneissic schist; (B). Gneissified granite (Orthogneiss); (C). Orthoamphibolite; (D). Reorientation of biotites, potassium feldspars, quartz recrystallization; (E). Symplectic or myrmekite association of orthogneiss; (F). Plagioclase in fine orthoclase flecks (antiperthites) and potassium feldspars in streaks In these gneisses, quartz is found in symplectic or myrmekite association (Fig.15E and F). It occurs in the form of fine vermicules, localized at the edges of large feldspar crystals (orthoclase, microcline, but often plagioclase). Microscopically, the plagioclase is rich in fine orthoclase flecks (antiperthites) and the potassium feldspars in albite streaks. Myrmekites are also present (Fig.15E). Phyllites According to stratigraphic data from this area, phyllites are rocks underlying itabirite. They can be observed at three levels. First, basal phyllites are represented by very fine-grained, dark greenish-grey pelites, with minor intercalations of quartzite and itabirite. This is followed by very fine-grained, medium to pale greenish-gray phyllites with locally deformed quartz bands/veins. Finally, there are iron oxide-banded phyllites, with a medium to dark brownish-red color and fine iron oxide bands. Quartzites and cherts The quartzites and cherts of Mount Simandou are the basic formations on which the itabirites abut. These formations are closely associated with the basal phyllites. Microscopically, the quartzites have a granoblastic texture, consisting of quartz, garnet, pyroxene and opaque minerals. Similarly, cherts are composed of silica or microcrystalline quartz. Amphibolites and pegmatites These formations are less abundant in the Tokadeh-Beeton-GangraYeulliton chain. They are intercalated in the gneissic basement. The amphibolites in this area derive from the regional metamorphic transformation of basic gabbro-type rocks (orthoamphibolite) in the Nimba region. They occur as dykes (Fig.16A). Microscopically (Fig.16B and 16C), these amphibolites consist of amphibole, plagioclase, biotite, chlorite, hypersthene, diopside, epidote, quartz, sericite, apatite, muscovite and opaque minerals. Amphiboles account for over 50% of this rock. The pegmatitic facies takes the form of a vein or dyke (Fig.16D) that is genetically related to the granitic pluton. It is formed of residual water-rich liquid from the final crystallization of granitic magma. The presence of water facilitates the diffusion of chemical elements, enabling the growth of large crystals. Microscopically (Fig.16), pegmatite from a World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1969 320m-deep core hole on Mount Tokadeh is composed of large minerals: quartz, plagioclase, microcline, muscovite, biotite and opaque minerals [13]. Figure 16 Macroscopic and microscopic aspects of amphibolites (A) and pegmatites (D). (A). Macroscopic aspect of an amphibolite dyke; (B) and (C). LPA microphotograph of the amphibolitic dyke. (D) Macroscopic aspect of a pegmatite dyke; (E) and (F) LPA microphotograph of the pegmatitic dyke Granites They are abundant in the Nimba region (sub-prefectures of Tounkarata, N'Zoo and Bossou, on the Guinean side). Among these different granites, the most characteristic are the pale pink granites. Microscopically, they consist of: quartz, orthoclase, muscovite, biotite, plagioclase and microcline (Fig.17) [13] Figure 17 Macroscopic and microscopic appearance of pink granite [13]. (A). Granite sample; (B). Inclusion of muscovite microcrystals in potassium feldspars in PAL; (C). Microcline phenocrysts surrounded by microcrystals of biotite, quartz and potassium feldspar (Fk). Pl: plagioclase; Fk: potassic feldspar; Bt: biotite; Qz: quartz; Mc: microcline; Ms: muscovite World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1970 5.2.2. Metallographic data From a metallogenic point of view, all the known iron deposits and showings on Mount Nimba and its western extension, as well as the Mount Simandou deposit (Pic de fon), display a diversity of iron-bearing minerals. Among these minerals, two primary iron ore minerals have been identified: magnetite and pyrite [13]. Magnetite (Fig.18C) has equidimensional grains, while pyrite grains (Fig.18B and D) are automorphic, fine to medium. Magnetite has a grey-brown hue, while pyrite has a light yellow hue. Hematite also occurs occasionally as martite. It arises from the oxidation of magnetite and can also be observed along the cleavage planes in magnetite crystals. Martite appears thanks to secondary transformations caused by surface alteration agents (pseudomorphosis of magnetite into hematite) and/or goethite (Fig.18). Figure 18 Microscopic appearance of magnetite quartzite slides viewed under a metallogenic microscope [13]. (A). Magnetite with striking structures (seen in polished section); (B). Xenomorphic magnetite with automorphic to subautomorphic pyrite; (C). SEM image of an itabirite matrix showing abundant goethite; (D). SEM image of an itabirite matrix showing abundant siderite Mag: magnetite, Py: pyrite, Hem: hematite 5.2.3. Structural data The data we have on the structural analysis of iron formations (BIF) are derived from various previous works [11],[13],[33],[35]. Our synthesis consists of noting the various structural features associated with the previously described rocks and their associated deformation mechanisms. The iron formations of Monts Nimba and Mont Simandou have been affected by two types of deformation (D1 and D2), both belonging to the Paleoproterozoic domain [36],[37]. The D1 deformation is typical of tangential tectonics, characterized by an S1 foliation, developed throughout the tectonic stack. This foliation (S1) carries a stretching lineation L1, oriented NNW-SSE to NNE-SSW in the Simandou and NW-SE to NNW-SSE in the Nimba Mountains. The stretching lineation (L1) is marked in ductile shear zones developed through various levels of the lithotectonic pile. The overall shear direction is southward in these zones, according to tectonic analyses. Indeed, the metamorphic conditions of deformation (D1) vary according to the lithotectonic units, from low degree, medium degree to high degree. In addition, deformation (D2) is characterized by regional-scale P2 folds [36]. These folds are synchronous with an S2 crenulation schistosity, and associated with ductile, brittle, generally senestial World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1971 detachments. Indeed, D2 structures are characteristic of low-grade or low-intensity metamorphic conditions (Chl, Ser or actinote) [36]. 5.3. Metamorphism The magnetite-bearing quartzites of Mont Klahoyo and Tia, as well as their gneiss counterparts, have been affected by granulite facies metamorphism [9]. This metamorphism is expressed by a number of mineralogical equilibria that differ from one lithology to the next and can be observed in both types of deposit: i) in garnet amphibolo-pyroxenite : orthopyroxene + clinopyroxene + brown hornblende + plagioclase (1), ii) in magnetite quartzite (Itabirite): hypersthene + magnetite + garnet + clinopyroxene + quartz (2) and iii) in hypersthenites: hypersthene + garnet + magnetite (3) , hypersthene + garnet + grünerite (4). Paragraphs (1), (2), (3) and (4) confirm that these rocks are typically granulite facies. In addition, the presence of grünerite is evidence of hypersthene retromorphosis. This retromorphosis is manifested in parageneses (1) and (2) by the transformation of clinopyroxenes and actinolitization of brown hornblende, sometimes accompanied by traces of chlorites and calcites. The magnetite-bearing quartzites of Mount Nimba and Simandou, and the various lithologies associated with them, have been affected by prograde metamorphism. This metamorphism varies from greenschist facies to granulite facies to amphibolite facies [13],[33]. These metamorphisms have made it possible to highlight three metamorphic zones (the low-grade zone, the medium-grade zone and the high-grade zone of metamorphism) as a function of depth, temperature and pressure [13]. Indeed, they are characterized by a number of mineralogical equilibria (Table 5). In general, the intensity of metamorphism in these regions increases from east to west [13]. 5.4. Geochemistry of BIFs Ivory Coast and Guinea 5.4.1. Geochemistry of Ivory Coast BIFs According to the results of chemical analyses of BIFs carried out by [9], BIFs are rich in Fe2O3, FeO and SiO2. These BIFs are rich in Fe2O3, FeO and SiO2. On the other hand, BIFs are poor in TiO2, CaO, MgO, K2O, MnO, Na2O, Al2O3 and P2O5. Geochemical analyses carried out on itabirite samples collected by [9] at Mont Tia, were not assayed for trace elements. Since [9], no geochemical work has been carried out on the BIFs of western Ivory Coast. 5.4.2. Geochemistry of Guinea's BIFs According to the results of chemical analyses carried out by Mohamed et al. (2019), BIFs are rich in Fe2O3, FeO and SiO2. On the other hand, we note that the BIFs are poor in TiO2, CaO, MgO, K2O, MnO, Na2O, Al2O3, and P2O5 as the percentages of these elements are low (Fig.19 and 20). Trace elements in itabirites from the Nimba region have been normalized to chondrites [38]in [13]. Indeed, the magnetite itabirite (SIF.1) shows enrichment in Al, Zn, Pb, Co and depletion in Mg, Ti, V and Ni. On the other hand, itabirite with magnetite (SIF. 2) shows enrichment in Mg, Ti, Zn, Cu and depletion in Mn, Al, V, Ni and Co (Fig.19A). Chlorite itabirites (SIF. 8) and garnet-granite itabirites (SIF. 19) show enrichment in Mg, Zn, Pb, but depletion in Al, Ti, V, Ni and Co (Fig.19B). Garnet (SIF. 33), transition zone (SIF.Tz. 41), garnet-grünerite (SIF. 43 and 45) and brown hornblende (OIF. 24) itabirites show enrichment in Mg, Ti, Zn, Pb and depletion in Mn, Al, V, Ni, Co (Fig.19C). All itabirites from the Nimba region show a significant Pb peak. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1972 Figure 19 (A). Trace element spectra normalized to itabirite chondrite (SIF.1 and SIF.2) from the Nimba region; (B). Trace element spectra normalized to itabirite chondrite (SIF.8 and SIF.18) from the Nimba region; (C). Chondritenormalized trace element spectra of itabirites (SIF.33, SIF.41, SIF.43 and 45, OIF.24 and OIF.25) from the Nimba region; (D). Evolutionary spectra of major elements (SiO2, Al2O3, Fe2O3 and FeO) in itabirites from Ivory Coast and Guinea [38] in [13] World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1973 Figure 20 Major element differentiation diagrams based on Fe2O3 for BIFs from Mont Tia (Ivory Coast and Mont Nimba (Guinea) Figure 20 (continued) Diagrams of major element differentiation as a function of Fe2O3 in the BIFs of Mont Tia (Ivory Coast) and Mont Nimba (Guinea) 6. Discussion 6.1. Petrography Magnetite quartzites, garnet gneisses, granites, amphibolo-pyroxenites and hypersthenites are found in the Mount Klahoyo and Tia area. Of these different formations, only the magnetite quartzites are host to iron mineralization. These formations are encased in a band of migmatitic gneiss [9],[10]. These same itabirites were previously described in the Yepleu-Bounta area by [25],[32]. They were also recorded in the southwestern part of Guiglo by [6],[7] affected by magnesian rocks and to the northwest in the Odienné department by [18]. World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1974 According to [9] and [10], the BIF or itabirite of Mount Klahoyo and Tia are rocks of sedimentary origin belonging to the Archean and the other formations observed are of metamorphic and magmatic origin. Similarly, itabirite-type formations similar to those described in western Ivory Coast have been highlighted in Guinea at Mount Nimba by [11],[13],[33]. These same itabirites have been recorded at Mount Simandou (Guinea) in the Pic de Fon deposit by [35]. These itabirites are sedimentary rocks of Proterozoic age [13],[33]. They are associated with magmatic, metamorphic formations of Archean age (gneisses, granites, amphibolites, quartzites, schists, phyllites, cherts and micaschists) [13],[33]. They are locally associated with volcanosedimentary rocks according to [11]. Indeed, the magnetite-bearing quartzites described above are similar to those found in various parts of the West African craton. For example, [4] highlights the itabirites of Guelb El Rhein in northern Mauritania, which rest on a host rock composed of gneiss, quartzite, amphibolite, leptynite and pegmatite. These itabirites are of Archean (the western extension of Tiris) and Proterozoic (Koedia Idjil) age and sedimentary origin, but the rocks associated with them are of volcanic origin. In Brazil, [39] found itabirites in sedimentary and volcanic rocks hosted in gneisses. In Ukraine, [40] identified itabirites in the Krivoy Rog basin. These itabirites are described as Proterozoic taconite. The same type of formation has also been described in Canada, in the Grenville province of Quebec [10]. 6.2. Metallography The metalliferous paragenesis found at Mount Klahoyo consists of iron oxides (magnetite and hematite) and sulfides (pyrite, chalcopyrite and ilmenite). According to [9],[10], magnetite represents the main iron ore in the BIFs of western Ivory Coast. [32] has identified a quasi-identical paragenesis in the Yepleu-Bounta area consisting solely of iron oxide (magnetite and hematite). He also deduced that only magnetite represents the main iron ore in the Yepleu-Bounta BIFs. However, this same paragenesis has been identified in Guinea, more specifically at Mount Nimba and Simandou, consisting of iron oxide (magnetite and hematite), sulfides (pyrite), carbonates (siderite) and goethite. According to [13], magnetite and pyrite represent the main iron ores in the Mount Nimba BIFs. [4] identifies a similar paragenesis consisting of iron oxide (magnetite and hematite) and sulfide (pyrite). 6.3. Structural In the study area, particularly at Mount Klahoyo, the structural markers of deformation are: folds (similar folds, sometimes isoclinal, antiformal, synformal with NE to SE plunging axis, intrafolial S-type and Z-type folds, entrainment folds, and chevron folds), stratifications, foliations, crenulation schistosities, stretching lineations and the intersection lineation between S1 and S2 (L1-2). These folds and foliations were highlighted by the flattening mechanism. There are also NNW-SSE to NNE-SSW oriented fractures and faults affecting the Itabirites. In fact, these various faults and fractures intersect and offset the ductile formations in a NNE-trending sinister movement, testifying to polyphase tectonics (D1 and D2). The main direction of these faults and structures is NE-SW, which according to [18] is characteristic of Birrimian formations. All these structures reveal the existence of a shear corridor. Furthermore, the work at Mount Klahoyo is similar to that in Guinea, particularly at Mount Nimba and Mount Simandou, according to [34]. The NE-SW-trending foliations observed at Mount Klahoyo are identical to those identified at the NESW to NNE-SSE-trending Nimba and the NNE-SSW-trending Mount Simandou [34]. According to [4], the iron deposits of Mauritania (Guelb El Rhein deposit) have also undergone large-scale ductile deformation composed of two phases linked to a compressive regime. This compressive mechanism generated an isoclinal fold and a second one at the origin of the synformal fold. 7. Conclusion Banded iron formations (BIFs) are the most important source of iron ore in the world, particularly in Ivory Coast and Guinea, where they are deposits of high economic value. Most BIFs were formed in the Precambrian, Archean and Proterozoic eras. They are distinguished into two types: Algoma and Lake Superior. The Algoma type is the oldest, more than 2.6 Ga old, typical of Archean formations. The banded iron formations of Mount Klahoyo and Tia (Ivory Coast) belong to this type. The Upper Lake type, on the other hand, is specific to Proterozoic formations. In fact, the itabirites of Guinea are of the Lac Supérieur type, formed in the Proterozoic. The BIFs of Ivory Coast and Guinea were subjected to two types of tectonic events (ductile deformation or D1 and brittle deformation or D2), generating several types of structures. Indeed, ductile deformation or D1 has led to the development of various structures (folds, foliations and lineations) in these two countries. In Ivory Coast, brittle deformation or D2 also led to the formation of faults, fractures, veins and joints, while in Guinea, it led to the formation World Journal of Advanced Research and Reviews, 2025, 28(02), 1953-1977 1975 of folds (P2) [36]. The magnetite quartzites of Guinea, like those of Ivory Coast, are rocks of sedimentary origin. They have a granoblastic or bedded texture. Geochemical data revealed similar scattered and negative correlations in both countries' BIFs with SiO2, TiO2, CaO, MgO, K2O, MnO and P2O5, in addition to the correlations observed only with Al2O3 and FeO in Guinea's BIFs. The metallogenic data reveals that the BIFs from these two countries are similar. This is since magnetite represents the main iron ore in the BIFs of both countries, in addition to pyrite, which is the second ore in Guinea, and hematite, which is the second ore in Ivory Coast. Both deposits are of sedimentary origin. Indeed, this study shows on the one hand that the BIFs of these two countries are lithologically, structurally and metallogenically similar. Thus, we confirm the hypotheses of the players [11],[13] who suggested a similarity of the BIFs of these two countries. 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