Provenance of metasiliciclastic rocks at the northwestern margin of the East Gabonian Block: Implications for deposition of BIFs and crustal evolution in southwestern Cameroon

Tamehe, Landry Soh; Wei, Chongtao; Ganno, Sylvestre; Rosière, Carlos Alberto; Li, Huan; Soares, Mariana Brando; Nzenti, Jean Paul; Santos, João Orestes Schneider; Bekker, Andrey

doi:10.1016/j.precamres.2022.106677

Cited by 23 publications

(17 citation statements)

References 127 publications

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“…Published geochemical data and U-Pb-Hf-O isotopic data demonstrate a paradigm shift in the mantle thermal state and suggest that the protolith of granitic gneiss rocks was predominantly derived from Neoarchean charnockites and TTG suites of the Ntem Complex (Figures 9a and 10b) with a variable and episodic contribution from ca. 2.2-2.0 Ga charnockites of the Nyong (Soh Tamehe et al, 2022).…”

Section: Geodynamic and Tectonic Frameworkmentioning

confidence: 98%

Section: Regional Geologymentioning

confidence: 99%

“…This can be used to explain the greater endowment of iron deposits within the upper craton in the Nyong Complex. Djoukouo et al, 2021;Loose & Schenk, 2018;Nga Essomba et al, 2020;Owona et al, 2022;Owona, Ratschbacher, et al, 2020;Soh et al, 2021;Soh Tamehe et al, 2022) eny (e.g., Bouyo Houketchang et al, 2019;Djoukouo et al, 2021;Fuanya et al, 2019;Kamguia Woguia et al, 2022;Loose & Schenk, 2018;Moudioh et al, 2020;Owona et al, 2021;Owona et al, 2022;Owona, Ratschbacher, et al, 2020;Soh et al, 2021). Continental arcs have an extensive range of compositions, from silica-poor stages associated with the early stages of development of convergent plate margins to highly evolved magmas marking the end of subduction (Santos et al, 2021).…”

Section: Implications For Iron Mineralizationmentioning

confidence: 99%

“…The Palaeoproterozoic Nyong Complex is the result of plate tectonic processes between the São Francisco‐Nigerian Block and an ancient Congo megacraton (Figure 1a,b; Bouyo Houketchang et al, 2019; Feybesse et al, 1998; Ledru et al, 1994; Owona et al, 2022; Santos et al, 2021; Soh Tamehe et al, 2022). The greenstone belt has been demonstrated and constrained by amphibolite to granulite‐facies metamorphism.…”

Section: Geological Settingmentioning

confidence: 99%

“…Several iron deposits in the greenstone belts that surround them have been discovered (Figure 2a). The Nyong Complex iron deposits consist of metasedimentary and metavolcanic rocks as well as syn‐ to late‐tectonic intrusive (Soh et al, 2021; Soh Tamehe et al, 2022). Intrusions of metadiorites, granodiorites, and syenites from the Nyong Complex and post‐tectonic dolerites (Lerouge et al, 2006; Toteu et al, 1994) were observed.…”

Section: Geological Settingmentioning

confidence: 99%

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Petrology and geochemistry of metamorphosed rocks associated with iron formations of the Toko‐Nlokeng iron deposit, (Southern Cameroon): Implications for geodynamic evolution and mineralization

2023

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Detailed petrographic, lithostratigraphic, and geochemical data of metamorphosed orthogneisses and mafic‐ultramafic metavolcanic rocks intruded into the greenstone belt of the Toko‐Nlokeng iron deposit have enabled the reconstruction of the tectonic and geodynamic setting and crustal evolution of the Nyong Complex. Samples were collected from the drill holes TNF11_01 and TNF11_02 from 17.16 m to 335.85 m depth. The lithostratigraphy supported by field and petrographic observations outlines two main lithologies: Iron formations (IFs) and metamorphosed host rocks. The IFs (granular iron formations (GIF) and banded iron formations (BIF)) are intercalated with host rocks consisting of orthogneisses and mafic‐ultramafic rocks. New and published geochemical data of metamorphosed associated IFs from Anyouzok (TNF08 prospect) of the Toko‐Nlokeng iron deposit, Mewengo iron deposit, Bipindi, and Kribi metavolcanic rocks in the Nyong Complex, suggest that these rocks were formed by material from intrusive and extrusive magmatic episodes with mid‐ocean ridge basalts (MORB) contaminated by either subduction or crustal components. CaO/Al2O3 and (Gd/Yb)N ratios >1 and positive Nb anomalies in ultramafic rocks indicate a mantle plume source contaminated by metasomatized subduction mantle lithosphere. These data also show that the mafic‐ultramafic metavolcanic rocks derive from magma of basaltic and basaltic andesite compositions, with a tholeiitic to calc‐alkaline tendency characteristic of the upper mantle. These data reveal that gneisses derive from granite and diorite subalkaline, peraluminous, and ferroan to magnesian compatible with Cordilleran magmas and island arcs with polygenetic crustal signatures. All samples of mafic granulites, garnet‐amphibolite, metabasites, and ultramafic granulites in the Nyong Complex reveal no residual garnet and predominantly show ca. 4% partial melting of an amphibole‐spinel‐peridotite source in the Dy/Yb versus La/Yb. Otherwise, hornblendites of Toko‐Nlokeng display ca. 5% partial melting of an amphibole‐garnet‐peridotite source, average (Gd/Yb)CN ratio of the hornblendites is (Gd/Yb)CN = 7.56 > 2. This result suggests these hornblendites do not have the same magmatic source as other mafic‐ultramafic rocks of the Nyong Complex. Mafic‐ultramafic host rock protoliths are classified as E‐MORB, P‐MORB, and G‐MORB (hornblendites) compositional types and arc, back‐arc ‘B’ in subduction unrelated, rifted margin setting with minor crustal contamination. The tholeiitic to calc‐alkaline and peraluminous affinity of these rocks indicate a mature arc and thickened crust during the Eburnean Trans‐Amazonian orogenic belts of the Congo Craton. This study shows that the host rocks were emplaced in a convergent tectonic setting and affected by a syn‐collisional episode where melts were derived from the partial melting of thick basaltic crust into amphibolite–eclogite facies in the subduction zone. The geochemical signatures of the mafic‐ultramafic rocks support the tectonic accretionary of the Palaeoprotero...

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Section: Geodynamic and Tectonic Frameworkmentioning

confidence: 98%

Section: Regional Geologymentioning

confidence: 99%