Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS
The Banyo area, located in the southern prolongation of the Mayo Nolti shear zone trend, belongs to the western Cameroon domain of the Neoproterozoic Central African Belt (NCAB). It is made of granitic rocks that intrude metamorphic banded rocks. Both are sometimes mylonitized. The pluton is dominan...
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2025-03-01
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| author | Alys Calore Mengou Bertille Edith Bella Nke Théophile Njanko Pierre Rochette Roland Kanse Onana François Demory Emmanuel Njonfang |
| author_facet | Alys Calore Mengou Bertille Edith Bella Nke Théophile Njanko Pierre Rochette Roland Kanse Onana François Demory Emmanuel Njonfang |
| author_sort | Alys Calore Mengou |
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| description | The Banyo area, located in the southern prolongation of the Mayo Nolti shear zone trend, belongs to the western Cameroon domain of the Neoproterozoic Central African Belt (NCAB). It is made of granitic rocks that intrude metamorphic banded rocks. Both are sometimes mylonitized. The pluton is dominantly of paramagnetic behavior, as shown by the hysteresis loops and the Fe-bearing silicates crystals are the susceptibility carriers. AMS ellipsoids are dominantly of oblate shape, pointing to the importance of flattening during pluton emplacement. The anisotropy degree of magnetic susceptibility values (≤1.20) characterize the magmatic fabric flow. The microstructural study of the granite reveals magmatic, sub-magmatic, solid-state and mylonitic deformations. Field and AMS fabrics show evidence of polyphase deformation (D<sub>1</sub>–D<sub>3</sub>). The D<sub>1</sub> phase is of flattening mechanism (flat-laying foliation). The D<sub>2</sub> phase points to sinistral ductile simple shear accommodating moderate to steep dipping and N-S- to NW-SE-oriented foliations in plutonic and country rocks and conjugated E-W mylonitic foliation in country rocks bearing sub-horizontal- to moderate-plunge mineral stretching lineation. The D<sub>3</sub> phase is of dextral ductile simple shear. σ- and δ-type kinematic markers in the pluton indicate sinistral top-to-south sense of shear movement, indicating a non-coaxial component of the tectonics. The magnetic fabrics of the pluton are parallel to those of the D<sub>2</sub> deformation phase of the study area. The transpressive D<sub>2</sub> and D<sub>3</sub> events correlate with the D<sub>2</sub> and D<sub>3</sub> phases of the Pan-African tectonic dated at 613–585 Ma and 585–540 Ma, respectively. The pluton, then, emplaced during regional sinistral D<sub>2</sub> deformation under transpressive regime. The emplacement of the NE Banyo granite took place as rock strips sheared in sinistral sense of shear movement. |
| format | Article |
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| institution | Kabale University |
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| spelling | doaj-art-18e409a3ef074ae4bf51da7c46bcba342025-08-20T03:43:36ZengMDPI AGGeosciences2076-32632025-03-011539910.3390/geosciences15030099Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMSAlys Calore Mengou0Bertille Edith Bella Nke1Théophile Njanko2Pierre Rochette3Roland Kanse Onana4François Demory5Emmanuel Njonfang6Soil Analysis and Environmental Chemistry Research Unit (SAERU), Department of Earth Sciences, University of Dschang, Dschang P.O. Box 67, CameroonLaboratory of Geosciences and Sustainable Development, Faculty of Sciences, University of Maroua, Maroua P.O. Box 814, CameroonSoil Analysis and Environmental Chemistry Research Unit (SAERU), Department of Earth Sciences, University of Dschang, Dschang P.O. Box 67, CameroonCentre de Recherche et d’Enseignement de Géosciences de l’Environnement (CEREGE) UMR7330, Aix–Marseille Université CNRS, 13545 Aix-en-Provence, FranceSoil Analysis and Environmental Chemistry Research Unit (SAERU), Department of Earth Sciences, University of Dschang, Dschang P.O. Box 67, CameroonCentre de Recherche et d’Enseignement de Géosciences de l’Environnement (CEREGE) UMR7330, Aix–Marseille Université CNRS, 13545 Aix-en-Provence, FranceLaboratory of Geology, University of Yaoundé I, Yaoundé P.O. Box 47, CameroonThe Banyo area, located in the southern prolongation of the Mayo Nolti shear zone trend, belongs to the western Cameroon domain of the Neoproterozoic Central African Belt (NCAB). It is made of granitic rocks that intrude metamorphic banded rocks. Both are sometimes mylonitized. The pluton is dominantly of paramagnetic behavior, as shown by the hysteresis loops and the Fe-bearing silicates crystals are the susceptibility carriers. AMS ellipsoids are dominantly of oblate shape, pointing to the importance of flattening during pluton emplacement. The anisotropy degree of magnetic susceptibility values (≤1.20) characterize the magmatic fabric flow. The microstructural study of the granite reveals magmatic, sub-magmatic, solid-state and mylonitic deformations. Field and AMS fabrics show evidence of polyphase deformation (D<sub>1</sub>–D<sub>3</sub>). The D<sub>1</sub> phase is of flattening mechanism (flat-laying foliation). The D<sub>2</sub> phase points to sinistral ductile simple shear accommodating moderate to steep dipping and N-S- to NW-SE-oriented foliations in plutonic and country rocks and conjugated E-W mylonitic foliation in country rocks bearing sub-horizontal- to moderate-plunge mineral stretching lineation. The D<sub>3</sub> phase is of dextral ductile simple shear. σ- and δ-type kinematic markers in the pluton indicate sinistral top-to-south sense of shear movement, indicating a non-coaxial component of the tectonics. The magnetic fabrics of the pluton are parallel to those of the D<sub>2</sub> deformation phase of the study area. The transpressive D<sub>2</sub> and D<sub>3</sub> events correlate with the D<sub>2</sub> and D<sub>3</sub> phases of the Pan-African tectonic dated at 613–585 Ma and 585–540 Ma, respectively. The pluton, then, emplaced during regional sinistral D<sub>2</sub> deformation under transpressive regime. The emplacement of the NE Banyo granite took place as rock strips sheared in sinistral sense of shear movement.https://www.mdpi.com/2076-3263/15/3/99deformationshear zonegraniteBanyopan-African tectonicCameroon |
| spellingShingle | Alys Calore Mengou Bertille Edith Bella Nke Théophile Njanko Pierre Rochette Roland Kanse Onana François Demory Emmanuel Njonfang Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS Geosciences deformation shear zone granite Banyo pan-African tectonic Cameroon |
| title | Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS |
| title_full | Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS |
| title_fullStr | Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS |
| title_full_unstemmed | Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS |
| title_short | Structural Characterization of the Pan-African Banyo Area (Western Cameroon Domain): Constraints from Field Observations, Structures and AMS |
| title_sort | structural characterization of the pan african banyo area western cameroon domain constraints from field observations structures and ams |
| topic | deformation shear zone granite Banyo pan-African tectonic Cameroon |
| url | https://www.mdpi.com/2076-3263/15/3/99 |
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