Metamorphic zircons from North Cameroon; implications for the Pan-African evolution of Central Africa

Toteu, S.F.; Macaudiere, Garoua; Bertrand, Jean; Dautel, D.

doi:10.1007/bf01879214

Cited by 49 publications

(27 citation statements)

References 26 publications

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“…In Cameroon, the early tectonic evolution of the central Africa Fold Belt involve thrusting and shortening that leads to the crustal thickening between 630-620 Ma [14]. The age of the biotite-muscovite granite is at the error limit similar to the age of the thrusting event date at 630 ±5 Ma in the Poli micaschist [31], and at 620 ±10 Ma in the Yaoundé granulite [21]. It is not unlikely to consider that the studied biotite-muscovite granite was trigger because of the pre-D2 (perhaps syn-D1) activity of the CCSZ at 647 ±46 Ma in association with the collisional process.…”

Section: Discussionmentioning

confidence: 77%

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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Section: Discussionmentioning

confidence: 77%

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 CAFB was interpreted as a zone of continent-continent collision [13,[17][18][19][20][21][22][23][24][25][26][27] involving three major landmasses: the São Francisco-Congo Craton (SFCC), the Eastern Sahara block and the West African Craton [11] (Figure 1). It comprises two main granulitic rock suites: an Archaean generation in the forefront basement of the Oubanguides chain and a post Archaean generation likely Pan African within the inner zone of that orogeny [28].…”

Section: Regional Geologymentioning

confidence: 99%

“…The metamorphism is of medium-to high-pressure type and localized anatexis resulted in the genesis of migmatites. The associated plutonism evolved from calc-alkaline to alkaline compositions [21,36].…”

Section: Regional Geologymentioning

confidence: 99%

Na-Metasomatism and Uranium Mineralization during a Two-Stage Albitization at Kitongo, Northern Cameroon: Structural and Geochemical Evidence

Kouske¹,

Suh²,

Ghogomu³

et al. 2012

IJG

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Mapping and documentation of lithological varieties and their corresponding geochemistry at the Kitongo uranium mineralization were concerned. The Kitongo U occurrence is hosted by granitic rocks that include interleaved sequences of metasedimentary and metavolcanic rocks of the collectively termed Poli Group. U-mineralization and Na-metasomatism are related and structurally controlled. The most promising uraniferous bodies are intimately related to intersecttions between the ductile ENE-trending faults and the brittle conjugate R' faults postdating the shearing event. The concentration of uranium at fault intersections rather than along individual faults suggests that these zones that are dilatational in nature were also highly permeable and therefore the hydrothermal fluids ponded there could readily precipitate U therein. A two-stage albitization has altered the foliated granitic host rock and the second albitization that has overprinted the first one is more effective at fault intersections. Whole rock geochemistry was performed by using ICP-MS and ICP-AES respectively for major oxides, trace and REE. The U-bearing rock suite exhibits restricted range in SiO 2 concentration (62.89% -70.91%) and Al 2 O 3 (13.16% -18.59%) and it is poor in MgO (0.02% -1.03%), CaO (0.24% -1.88%) and K 2 O (0.08% -5.32%). The mineralized rocks are however comparatively richer in Na 2 O (4.33% -10.92%) compared to their barren counterparts. The host granite and associated granodioritic rocks in the area are weakly metaluminous, peralkaline, and are calc-alkaline. They are moderately to strongly fractionated and have tholeiitic and shoshonitic affinities with moderate to high HFSE (high field strength elements) and LILE (large ion lithophile elements) enrichment. The Rb/Sr, Rb/Ba and Sr/Ba ratios are 0.31, 0.14 and 1.48, respectively. U content in the mineralized granite is up to 651 ppm while the non-mineralized rock has only 2.4 ppm U. The REE patterns of the granite show LREE enrichment and strong Eu negative anomalies (Eu/Eu* = 0.03 to 0.48). The main mineralization stage characterized by local U, Na, Pb, Zn, Ga, Hf, Sr, Fe, Al, P and Zr enrichments is related to the second albitization event and could probably be associated in time with the calcite-uranium stage. The identification of fault segments favorable for uranium mineralization in northern Cameroon (Poli area) is important for understanding the genesis of hydrothermal ore deposits within continental strike-slip faults and therefore has great implications for exploration strategies.

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“…That collision structured the Pan-African North Equatorial belt which extends in Sudan, Central African Republic, Cameroon and through correlations with North-East Brazil (Castaing et al, 1994;Nzenti et al, 1998;Toteu et al,2001;Abdelsalam et al, 2002;Oliveira et al, 2006).In West Cameroon, Pan-African massifsare widely distributed (Fig.1b) andare described as syn to post-collisional, calc-alkaline, ferro-potassic and metaluminous (Tchouankoue, 1992;Nguiessi et al,1997;Tagne -Kamga, 2003;Nzolang et al, 2003;Tetsopgang, 2003;Djouka Fonkwe et al, 2008).According to available ages, the massifswere emplaced during the Pan -African D2 deformation event. The emplacement age (Rb -Sr whole rock and Th -U -Pb methods) are between 720-540 Ma (Toteu et al, 1990;Tchouankoue, 1992;Nguiessi et al, 1997;Tagne -Kamga, 2003;Nzolang et al, 2003;Tetsopgang, 2003;Djouka Fonkwe et al, 2008;Njiekak et al, 2008., Tchaptchet Tchato et al, 2009Kwekam et al, 2010). Plutonic rocks in Bayon area in the southwestern part of the Cameroon orogenic belt havenot yet been investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

Geochemistry of the Bayonplutonic Complex – Western Cameroon

Belnoun¹,

Tchouankoue²,

Itiga³

et al. 2013

Glo Jnl Geo Sci

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The BayonNeoproterozoic plutonic complex located in Western Cameroon intrudes gneisses of Paleo to Neo Proterozoic age. The complex is composed of gabbro, monzogabbro and monzonites frequently crosscut by trachytic and granitic veins. /Lu N = 14 -27) with none or negligible Eu anomalies. The monzonite shows also moderate fractionatedpatterns (La N /Lu N = 20 -27) with fairly positive Eu anomalies. All the studied rocks show flat HREE features. The primitive mantle-normalized element patterns are almost homogeneous with negative anomalie in Ta, Nb, Th, P and Ti. Sm/Nd-wr-Cpx-Pl ages of the complex are 580 ± 13 Ma; 553 ± 32 Ma for the monzogabbro and 547 ± 26 Ma for the monzonite. The Nd/Sr isotopic compositions show that the Bayon plutonic rocks were generated by partial melting of subcontinental lithospheric mantle. The depleted mantle Nd model age TD M of 1.6 -1.7 Ga indicates that the studied rocks originated by partial melting of Mesoproterozoic mantle.

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Metamorphic zircons from North Cameroon; implications for the Pan-African evolution of Central Africa

Cited by 49 publications

References 26 publications

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

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

Na-Metasomatism and Uranium Mineralization during a Two-Stage Albitization at Kitongo, Northern Cameroon: Structural and Geochemical Evidence

Geochemistry of the Bayonplutonic Complex – Western Cameroon

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