The Ntui-Betamba high-grade gneisses: a northward extension of the Pan-African Yaoundé gneisses in Cameroon

Ngnotue, Timoléon; Nzenti, Jean Paul; Barbey, Pierre; Tchoua, Félix M.

doi:10.1016/s0899-5362(00)00094-4

Cited by 100 publications

(57 citation statements)

References 16 publications

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“…The Pan-African belt also known as Central African Fold Belt (CAFB) or Pan-African North Equatorial Fold Belt [12], is a Neoproterozoic orogen linked to the Trans-Saharan belt of western Africa and to the Braziliano Orogen of northeastern Brazil. The Neoproterozoic belt in Cameroon is subdivided into three main domains [13][14][15][16][17], from south to north (Figure 1(a)) : 1) The southern domain comprises Neoproterozoic metasedimentary units, such as the Ntui-Betamba, Yaoundé and Mbalmayo units; the protoliths of these units were deposited in a passive margin environment at the northern edge of the Congo Craton and were metamorphosed under high P conditions at 616 Ma [12,15,18]. The rocks of this southern domain were thrusted onto the Archean Congo Craton towards the south [19].…”

Section: Lithologic Contextmentioning

confidence: 99%

“…These large NE-striking transcurrent faults, as well as the Adamaoua fault inside the central domain, are regarded as possible prolongations of the major shear zones of NE Brazil in a pre-drift Gondwana reconstruction [20]. This central domain consists of archean to paleoproterozoic high-grade gneisses intruded by widespread Neoproterozoic syntectonic plutonic rocks of high-K calc-alkaline affinities [13,14,17,[21][22][23][24][25][26];…”

Section: Lithologic Contextmentioning

confidence: 99%

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Geophysical and Geotechnical Investigations of a Landslide in Kekem Area, Western Cameroon

Epada¹,

Ganno²,

Tabod³

2012

IJG

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Geophysical and geotechnical surveys were conducted in the Western Cameroon (Kekem area) following a landslide on argillaceous material in order to understand the triggering processes and mechanisms of this landslide and to assess the stability of the slope. The geophysical soundings consisting of vertical electrical soundings with the Schlumberger electrode array configuration were carried out to monitor the behaviour of electrical resistivity in the landslide. Geoelectrical data showed a zone of low resistivity values identified as a clayey sand-filled aquifer. This aquifer played an important role in the triggering process of the landslide. Geotechnical soundings showed that the aquifer had a thickness of 7.0 m. The depth from the landslide crest level to the failure surface reached 3.0 m and 20.6 m. Laboratory tests were then carried out in order to evaluate the cohesion of the soil and the angle of internal friction, and to calculate the safety factor in view of making a stability analysis. The laboratory results exhibited a soil with low consistency, almost doughy. The mean value of the safety factor (1.4) been lower than the slope stability coefficient (1.5), revealed that the slope is unstable, likely to know at any moment a reactivation of the slide. This study showed that electrical soundings coupled with geotechnical surveys are useful tools for the characterization of landslides.

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Section: Lithologic Contextmentioning

confidence: 99%

Section: Lithologic Contextmentioning

confidence: 99%

Geophysical and Geotechnical Investigations of a Landslide in Kekem Area, Western Cameroon

Epada¹,

Ganno²,

Tabod³

2012

IJG

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“…The paleoproterozoic ages referred to igneous and contemporary metamorphic ages. Archean crustal inheritances have been demonstrated in these rocks [2,16]. In Ngaoundere, granitoids are amphibole biotite granite, biotite granite and biotite and muscovite granite of mantle and crustal origin respectively [30].…”

Section: Geological Settingmentioning

confidence: 99%

“…The Central African Fold Belt (CAFB, Figure 1) is classicaly subdivided into three main lithostructural domains [16,18,32]. Between the West Cameroon Domain (WCD) and the Yaounde Domain (YD) lies the Adamawa Yade Domain (AYD).…”

Section: Introductionmentioning

confidence: 99%

The Pan-African Biotite-Muscovite Granite and Amphibole-Biotite Granite of Doua (Central Cameroon): Zircon Features, LA-MC-ICP-MS U-Pb Dating and Implication on Their Tectonic Setting

Kepnamou¹,

Alexandre²,

Klötzli³

et al. 2017

JGG

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The Doua area belongs to the Adamawa-Yadé domain (AYD) of the Central African Fold Belt (CAFB) in Cameroon. It is crossed by the Central Cameroonian Shear Zone (CCSZ). The purpose of this research is to determine the tectonic setting of granites of the studied area, based on their petrography, zircons feature and their ages. Petrographicaly, the Doua area is made up of plutonic rocks hosted in an ortho or paraderivative metamorphic basement. Amphibole-biotite granite (ABG) and biotite-muscovite granite form hills and crop out on the hill side, as flagstones in the valley or river bed, and as huge blocks. Amphibole-biotite granite is granular in texture and made up of amphibole, biotite, feldspar, accessory minerals (Sphene, zircon, and apatite) and secondary minerals (sericite). Biotite-muscovite granite (BMG) is granular to granular porphyritic in texture, made up of biotite, muscovite, plagioclase, K-feldspar, quartz, accessory minerals (zircon, opaques minerals) and secondary minerals (chlorite, sericite). ABG show elongated zircon grains with well-developed magmatic oscillatory zonation. LA-ICP-MS U-Pb data from these zircons define a concordia age of 607 ± 3 Ma and considered as crystallization age of the granite. BMG shows zircon with various shape and various internal structures (oscillatory zonation, sector zonation, blurred oscillatory zonation …) which are divided into two sets. The first set regarded as xenocryst from Paleoproterozoic granitoids emplaced at 2126 ±36 Ma or from sediments which detritus comes from such granitoids. The second set of zircons shows effects of recent lead lost and a subconcordant U-Pb age of 646 ± 39 Ma . ABG was emplaced during the D3 deformational phase, date at 607 ± 3 Ma , while BMG was trigger because of syn-D1 activity of the CCSZ at 647 ±46 Ma in association with the collisional process.

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“…In Cameroon, the Neoproterozoic realm [3][4][5][6][7][8][9][10] is subdivided into three domains from south to north (Fig. 1b): (1) The southern domain comprises Neoproterozoic metasedimentary units, such as the Ntui-Betamba, Yaoundé and Mbalmayo units; the protoliths of these units were deposited in a passive margin environment at the northern edge of the Congo Craton and were metamorphosed under high P conditions (T = 750-800°C, P = 0.9-1.3GPa) at 616 Ma [7,11,12]. Alkaline magmatism [13] has been also recognized in association with these Neoproterozoic units.…”

Section: Introductionmentioning

confidence: 99%

Neoproterozoic High-K Calc-Alkaline Granitoids from Bapa-Batié, North Equatorial Fold Belt, Central Cameroon: Petrogenesis and Geodynamic Significance

Chebeu¹

2011

TOGEOJ

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Neoproterozoic granitoids of the Bapa-Batié area crop out within the Central Cameroon Shear Zone (CCSZ). They comprise four rocks: (i) granodiorite, (ii) biotite-granite, (iii) biotite-amphibole-granite, and (iv) granitic dyke. The elongated shape of the plutons and foliation striking parallel to the CCSZ point to syntectonic magma emplacement. The rocks are metaluminous, weakly peraluminous, high-K, and calc-alkaline to shoshonitic ferro-potassic, with mineralogical and geochemical characteristics of I-type granitoids. The rocks are characterized by high Ba, Sr, Zr, Rb, Sr, low Ni and Cr contents, and by variable LREE enrichment, moderate HREE fractionation with strong negative to moderate Eu anomalies (in granodiorite, biotite-granite and biotite-amphibole-granite) and moderate to significant positive Eu anomalies (in granitic enclaves). Trace element distribution patterns show that all these rocks are distinctively depleted in Nb, P, Sr and Ti relative to other trace elements and indicate that these rocks were derived from crustal protoliths. Magmatic zircon grains in these granites yielded LA-ICP-MS U-Pb ages of 600 ± 3.7 Ma and 619 ± 29 Ma. The plutonic rocks of BapaBatié area resemble other Neoproterozoic high-K calc-alkaline granites of Cameroon and also display strong similarities with high-K calc-alkaline plutons of eastern Nigeria and the Borborema Province in NE Brazil.

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The Ntui-Betamba high-grade gneisses: a northward extension of the Pan-African Yaoundé gneisses in Cameroon

Cited by 100 publications

References 16 publications

Geophysical and Geotechnical Investigations of a Landslide in Kekem Area, Western Cameroon

Geophysical and Geotechnical Investigations of a Landslide in Kekem Area, Western Cameroon

The Pan-African Biotite-Muscovite Granite and Amphibole-Biotite Granite of Doua (Central Cameroon): Zircon Features, LA-MC-ICP-MS U-Pb Dating and Implication on Their Tectonic Setting

Neoproterozoic High-K Calc-Alkaline Granitoids from Bapa-Batié, North Equatorial Fold Belt, Central Cameroon: Petrogenesis and Geodynamic Significance

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