Neoproterozoic syn-collision magmatism in the Nkondjock region at the northern border of the Congo craton in Cameroon: Geodynamic implications for the Central African orogenic belt

Kamani, Michele Sandra Kamguia; Wang, Wei; Tchouankoue, Jean Pierre; Huang, Si-Fang; Yomeun, Bovari Syprien; Xue, Er-Kun; Lu, Gui-Mei

doi:10.1016/j.precamres.2020.106015

Cited by 19 publications

(9 citation statements)

References 76 publications

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“…The Grt‐amp gneiss and granitic gneiss samples from the TNF11 prospect are comparable to those of the syn‐collisional to post‐orogenic mantle‐fractionated granites of Batchelor and Bowden (1985; Figure 10e). These parameters indicate that the composition of the granitic gneisses samples from the study area is similar to the orthogneisses of the syn‐collisional to post‐orogenic described by Kamani et al (2021) and the granitic gneisses studied by Kouankap Nono et al (2022). The ternary diagram Hf‐Rb/30‐Ta 3 , proposed by Harris et al (1986), displays most of the granitic gneiss samples of the Toko‐Nlokeng and Mewengo iron deposits plots in the volcanic arc field, with a few samples in the intraplate field (Figure 10c).…”

Section: Discussionsupporting

confidence: 83%

“…(2) the Palaeoproterozoic Nyong Complex (e.g., Bouyo Houketchang et al, 2019;Loose & Schenk, 2018;Soh et al, 2021;Toteu et al, 1994) to the NW of the Congo Craton; and (3) the Neoproterozoic Yaoundé Group (e.g., Kamani et al, 2021;Nzenti et al, 1988;Toteu et al, 2022) representing the southern part of the Central African Pan-African Range that resulted from the convergence and continental collision at ca. 600 Ma (Figure 1a,b) (e.g., Kamani et al, 2021;Ledru et al, 1994;Owona, Ratschbacher, et al, 2020). In these areas, low to ultra-highpressure mafic-ultramafic rocks that have the most data indicate HP granulite facies assemblages (e.g., Lerouge et al, 2006;Loose & Schenk, 2018;Penaye et al, 2004).…”

Section: Regional Geologymentioning

confidence: 99%

“…The Precambrian basement of the Ntem Complex (Figure 1c) consists of three major structural units, including (1) the Congo Craton, locally called the Ntem Complex, consisting of Archean cratonic geological formations (e.g., Akame et al, 2021; Maurizot et al, 1986; Pouclet et al, 2007; Tchameni et al, 2010) in the south; (2) the Palaeoproterozoic Nyong Complex (e.g., Bouyo Houketchang et al, 2019; Loose & Schenk, 2018; Soh et al, 2021; Toteu et al, 1994) to the NW of the Congo Craton; and (3) the Neoproterozoic Yaoundé Group (e.g., Kamani et al, 2021; Nzenti et al, 1988; Toteu et al, 2022) representing the southern part of the Central African Pan‐African Range that resulted from the convergence and continental collision at ca. 600 Ma (Figure 1a,b) (e.g., Kamani et al, 2021; Ledru et al, 1994; Owona, Ratschbacher, et al, 2020). In these areas, low to ultra‐high‐pressure mafic‐ultramafic rocks that have the most data indicate HP granulite facies assemblages (e.g., Lerouge et al, 2006; Loose & Schenk, 2018; Penaye et al, 2004).…”

Section: Geological Settingmentioning

confidence: 99%

“…The Nyong Complex is generally considered to have been in an oceanic lithosphere subduction environment during the Palaeoproterozoic (Bouyo Houketchang et al, 2019; Loose & Schenk, 2018; Owona et al, 2022). Eburnian metamorphism is associated with syn‐and post‐tectonic magmatism where the low‐pressure metamorphic type developed beneath a volcanic chain in the adjacent island arc or continental margin and the high‐pressure metamorphic one developed beneath a trench zone with a compressional regime later overprinted by transpression and thrust tectonic faults (e.g., Kamani et al, 2021; Lerouge et al, 2006; Owona, Mvondo, et al, 2020). This work presents the lithostratigraphic, petrographic, and geochemical data of mafic‐ultramafic rocks associated with IFs collected from 17 to 410 m depth.…”

Section: Introductionmentioning

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: Discussionsupporting

confidence: 83%

Section: Regional Geologymentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

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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“…Migmatites are associated with orthogneisses and display high K to shoshonitic characters [12]. The spatial distinction in pre-to syn-orogenic magmatism allows recognition of a north to south potassium increasing trend, compatible with the existence of a northwestern trending Pan-African subduction (e.g., [15]). This sheared margin is marked by the superposition of two mylonitic foliations operating in opposing sense (at constant direction), under high and low metamorphic conditions (e.g., [13]).…”

Section: Geological Settingmentioning

confidence: 99%

Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line

et al. 2021

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In the western Cameroon, crop out several dyke swarms of Paleozoic–Mesozoic age. These dykes intrude the Precambrian basement in the southern continental part of the Cretaceous Cameroon Volcanic Line. In the Njimom area, two groups of mafic dykes that crosscut the Neoproterozoic basement rocks have been observed. A first group intrudes the mylonites whereas the second group intrudes the granites. The dykes are alkaline basalts and hawaiites. The mineralogical assemblage of both groups of dykes consists of plagioclase, clinopyroxene, altered olivine, and opaque oxides. The dykes that cross-cut the Precambrian mylonitic gneisses show moderate TiO2 (1.7–2.0 wt.%), low MgO (4.4–7.1 wt.%), and compatible trace element concentrations (e.g., Cr = 70–180 ppm; Ni = 30–110 ppm). The dykes that intrude the granites have TiO2 contents between 2.3 and 2.5 wt.% and moderate compatible trace element concentrations (e.g., Cr = 260–280 ppm; Ni = 170–230 ppm). MgO varies from 5.9 to 9.2 wt.%. All mafic dykes are enriched in light lanthanide element and show moderate Zr/Nb and high Zr/Y, Nb/Yb, and Ti/V ratios similar to those of average ocean island basalt (OIB)-type magmas. Some dykes that intrude the mylonites show evidence of contamination by continental crust. The composition of the clinopyroxenes of the dykes that intrude the mylonites clearly indicate different and unrelated parental magmas from dykes that intrude the granites. Contents and fractionation of the least and the most incompatible elements suggest low degrees of partial melting (3–5%) of heterogeneous source slightly enriched in incompatible elements in the spinel stability field. The geochemical features of Njimom dykes (in particular the dykes that intrude the granites) are similar to those of Paleozoic and Mesozoic dykes recorded in the southern continental part of the Cameroon Volcanic Line, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of the South Atlantic Ocean.

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Arc magmatism in the Nkoula granitoid suites, Central African Fold belt in Cameroon: evidence of a metasomatized high oxidized S- and I- type magma

Ntieche

Nguet

Moundi

et al. 2022

Int J Earth Sci (Geol Rundsch)

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Neoproterozoic syn-collision magmatism in the Nkondjock region at the northern border of the Congo craton in Cameroon: Geodynamic implications for the Central African orogenic belt

Cited by 19 publications

References 76 publications

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

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

Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line

Arc magmatism in the Nkoula granitoid suites, Central African Fold belt in Cameroon: evidence of a metasomatized high oxidized S- and I- type magma

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