Rose Noël NGO-BELNOUN

Geometry of the Pan-African nappes at the northern margin of the Congo Craton

Victor Metang, Jacqueline Numbem Tchakounté, Rose Noël Ngo Belnoun, Liliane Njips Nantchou Goudjou, Natacha Abigaelle Fosso Simo, Clarisse Rosine Bikaga et 2 autre(s)

Journal of African Earth Sciences

• #geological and geochemical analysis
• #clay minerals and soil interactions
• #geochemistry and elemental analysis
• #nappe

Nappe tectonics in the Matomb-Hegba area, South-Central Cameroon: Implications on the tectonic evolution of the Yaoundé Group in the Central African Orogenic Belt

Victor Metang, Henri Appolinaire Kenzo, Rose Noël Ngo Belnoun, Dior-Christelle Mboutchouang, Steve Franck Bamou-Wandji, Brigitte Domkam et 1 autre(s)

Geosystems and Geoenvironment

This paper documents the thrust tectonics in the Yaoundé Group using detailed field mapping and satellite imagery data. The litho-stratigraphic of the Matomb-Hegba area located W of the Pan-African Yaoundé series comprised two main metasedimentary units: (1) garnet-kyanite migmatites at the top, dated at 622 ± 43 Ma, and (2) garnet-rutile micaschists at the bottom, with ages ranging between 546 and 604 Ma. The contact between the two lithological units is materialized by a ductile shear zone evidenced by structural and remote sensing data: inversion of the foliation at the contact of the shear zone, P 2 folds with southern vergence, E-W to NE-SW sinistral shear planes, uniform dip (towards the SE) and several criteria indicating a sinistral and dextral kinematics respectively in light grey mylonites and in dark grey mylonites along the ductile shear zone. During D 2 deformation stage, subhorizontal S 2 foliation associated to NE-SW Lm 2 mineral lineations were developed in garnet-kyanite migmatites. The thrusting contact zone is characterized by mylonitized micaschists (light grey mylonites) and migmatites (dark grey mylonites) separated by talcschist and amphibolite boudins which would have served as a ‘‘soap layer’’ leading to the slipping of garnet-kyanite migmatites over garnet-rutile micaschists. The disposition of garnet-kyanite migmatites (sometimes outcrop in the form of klippes) over garnet-rutile micaschists, the presence of a ductile shear zone at the contact of the two lithological units, and the NE-SW mineral lineation suggest the existence of at least two tectonic nappes (garnet-kyanite migmatites and garnet-rutile micaschists) with NE-SW-trends in the Yaoundé Group. This nappe disposition induced by ductile shear corroborates well with the compressive shear tectonics as described in the NE of Brazil and in the northern and eastern part of the Saharan Block.

• #geological and geochemical analysis
• #geochemistry and geologic mapping
• #geological and geophysical studies worldwide
• #nappe

Lithochemistry, and gold and sulphides chemistry from the Abiete-Toko Gold District in the NW edge Congo Craton, Nyong Complex (SW-Cameroon): Insights into the primary source of alluvial gold deposits and occurrence in the area

Eugène Pascal Binam Mandeng, Thierry Bineli Betsi, Rose Noël Ngo Belnoun, Louise Marie Ngo Bidjeck Bondjè, Yvan Demonstel Ntomb, Stella May Nome et 3 autre(s)

Journal of Geochemical Exploration

• #geological and geochemical analysis
• #geochemistry and geologic mapping
• #geochemistry and elemental analysis
• #alluvium

Petrological and Geochemical Characteristics of the Cretaceous Ngaou Boh Anorogenic Complex (Adamawa Plateau, Cameroon Line): Preliminary Constraints

Zénon Itiga, Benoît Joseph Mbassa, Rose Noël Ngo Belnoun, Pierre Wotchoko, Dieudonné Tchokona Seuwui, Sébastien Owona et 3 autre(s)

Journal of Geosciences and Geomatics

The Cretaceous Ngaou Boh anorogenic complex (NBAC) located in the far North Adamawa Plateau, the centre domain of the Cameroon Line constitutes a plutonic-volcanic ring association. The whole rock K-Ar datation yields a crystallization age of ca. 74 Ma. Plutonic rocks comprise abundant alkali feldspar granites, scarce clinopyroxene-amphibole gabbros and alkali feldspar syenites. Alkali feldspar granites are leucocratic, coarse to fine-grained; quartz and K-feldspars are the major rock-forming mineral, besides minor oligoclase, biotite and accessory phases as sphene, zircon and opaques. Alkali feldspar syenites are mesocratic coarse-grained, mainly composed of K-feldspars with small amounts of quartz and biotite. Volcanic rocks consist of a basanite-trachyte-rhyolite suite. Basanites contain olivine and diopside phenocrysts and a groundmass essentially composed of plagioclase and titanomagnetite. Biotite-clinopyroxene trachytes and clinopyroxene-amphibole rhyolites have an almost homogeneous modal composition, mainly made up of sanidine and anorthoclase microliths, scarce phenocrysts of quartz, and minor crystals of biotite, clinopyroxene (augite) amphibole (pargasite, sandagaite); Fe-Ti oxides (ilmenite, titanomagnetite) and fibreglass are often isolated in the groundmass. Plutonic rocks are alkaline, weakly metaluminous with some alkali feldspar granites displaying agpaitic or peralkaline feature. Incompatible Trace elements (HFSE and LILE) distribution and chondrite-normalized REE patterns evidence a significant petrogenetic link between clinopyroxene-amphibole gabbros, alkali feldspar syenites and alkali feldspar granites. All the analysed samples are enriched in incompatible elements, indicating melts from spinel and garnet-bearing mantle source close to OIB component. Indeed, the (Tb/Yb)N ratios of both basanites (2.3-2.5) and clinopyroxene-amphibole gabbros (1.4-1.9) suggest different parental magma sources. Alkali feldspar granites appear as residue of magma differentiation led by crystal fractionation of liquid derived from the partial melting of spinel peridotite mantle. Clinopyroxene-amphibole rhyolites and biotite-clinopyroxene trachytes (Mg#=0.0-15.4) derive through fractional crystallization from basanites (Mg#=64.3-60.1), the most primitive mafic parental melt. Both plutonic rocks and lavas trends evidence a bimodality highlighted by a pronounced “Daly gap”.

• #geological and geophysical studies worldwide
• #geological and geochemical analysis
• #geological and geophysical studies
• #geology

Geochemistry of rutile from the Pan-African Yaoundé metamorphic group: Implications for provenance and conditions of formation

Louise Marie Ngo Bidjeck Bondjè, Thierry Bineli Betsi, Lionel Nicaise Yannick Mama Nga, Rose Noël Ngo Belnoun, Alexia Corinne Molotouala, Chris McFarlane et 1 autre(s)

Journal of African Earth Sciences

• #geological and geochemical analysis
• #geochemistry and geologic mapping
• #geochemistry and elemental analysis
• #geology

The Pan-African post-collision Hosséré Mana plutonic complex and associated Gapi Stock (Western Cameroon Domain, Cameroon): Petrology, mineralogy and geochemistry

Zénon Itiga, Bernard Bonin, Jacques‐Marie Bardintzeff, Pierre Wandji, Rose Noël Ngo Belnoun, Benoît Joseph Mbassa et 4 autre(s)

Journal of African Earth Sciences

• #geological and geochemical analysis
• #high-pressure geophysics and materials
• #earthquake and tectonic studies
• #geology

Structural Relationship between Brittle Deformation and Paleozoic to Mesozoic Basalt Dykes in the Precambrian Basement of the Southern Continental Part of the Cameroon Volcanic Line

Nicole Armelle Wambo Simeni, Depesquidoux Tchaptchet Tchato, Rose Noël Ngo Belnoun, Jean Pierre Tchouankoué, Alembert Alexandre Ganwa

International Journal of Geosciences

The work is a vivid description of the structural relationship between brittle deformation of the Precambrian basement in the southern continental part of the Cameroon Line and intrusive Paleozoic and Mesozoic basalt dykes swarms. A multidisciplinary approach that involves a combination of remote sensing techniques and field studies show that the major trend of brittle structures correspond to well-known regional structures: N70°E (Adamawa Shear Zone), N135°E (upper Benue trend) and N30°E (Cameroon Volcanic Line) corresponding to E-W and N-S directions respectively. Basalt dykes are associated to NE-SW, E-W and NW-SE oriented fractures. An integration of the available information on brittle structures and basalt dykes directions suggest an emplacement of the Mesozoic and Paleozoic basalt dykes structurally controlled by Precambrian structures that were originated through Riedel’s fracture kinematic model with dextral strike-slip Adamawa Shear Zone as the main shear zone during late stage of the Pan-African collision. Spatially, the restriction of the basalt dykes to the corridor of the Adamawa Shear Zone indicate that a rejuvenation of Precambrian faults may very well be the origin of the dykes with possibility that they may have been reworked several times during the Phanerozoic eon.

• #geological and geochemical analysis
• #geochemistry and geologic mapping
• #geological and geophysical studies worldwide
• #geology

Timing and tectonic implications of the Pan-African Bangangte syenomonzonite, West Cameroon: Constraints from in-situ zircon U-Pb age and Hf-O isotopes

Jean Pierre Tchouankoué, Xian‐Hua Li, Rose Noël Ngo Belnoun, Lucas Mouafo, Valderez P. Ferreira

Journal of African Earth Sciences

• #geological and geochemical analysis
• #geochemistry and geologic mapping
• #earthquake and tectonic studies
• #zircon

Petrology, Mineralogy, and Geochemistry of Kekem mafic Complex, Western Cameroon

Rose Noël Ngo Belnoun, Jean Pierre Tchouankoué, Friedrich Koller, Martin Thöni

Phaidra (Universität Wien)

• #geological and geophysical studies
• #geological and geophysical studies worldwide
• #geological and geochemical analysis
• #mafic