Petrology and geochemical framework of dolerites dykes of Temté, North Cameroon, Central Africa

Atour, M. Mey; Bardintzeff, Jacques-Marie; Mefire, Aminatou Fagny; Nkouandou, Oumarou Faarouk; Tchameni, Rigobert; Dinamou, A.

doi:10.1007/s11631-020-00432-4

Cited by 3 publications

(2 citation statements)

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“…Mafic dykes emplaced and crystallized in a very short time and can therefore retain useful information on tectonism and magmatism with high‐quality geochemical, isotopic and paleomagnetic signatures of their source. Mafic and felsic dyke swarms occur in numerous geologic and tectonic environments and their detailed study in space and time is indispensable in the understanding of several geological events (Aka et al, 2018; Asaah et al, 2022; Huang et al, 2021; Keutchafo Kouamo et al, 2019; Mey Atour et al, 2020; Ntieche et al, 2021; Silpa et al, 2021). Contrary to other geological formations of the CL, basaltic dykes have been less studied and those with transitional/subalkaline character have been described in some zones of the continental segment of this line (Aka et al, 2018; Asaah et al, 2022; Keutchafo Kouamo et al, 2019; Ngounouno et al, 2001; Tchaptchet et al, 2017; Tchouankoue et al, 2012; Tchouankoue et al, 2014).…”

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confidence: 99%

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Gountié Dedzo,

Klamadji,

Zangmo Tefogoum

et al. 2023

Geological Journal

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In this study, field descriptions of the dolerite dykes cross‐cutting the Pan‐African basement (DPB) and the dolerite and gabbroic dykes cross‐cutting the Cretaceous sedimentary basin (DGCSB) are used together with petrographic, bulk‐rock geochemistry, as well as Sr–Nd–Pb isotopic data to constrain the geodynamic setting and origin of these mafic (basanite, basalt and basaltic andesite in composition) rocks that outcrop in the Figuil–Léré area. The DPB dykes are alkaline with SiO2 of 46.63–49.03 wt% and MgO of 3.93–7.11 wt%. In contrast, the DGCSB dykes are subalkaline with SiO2 ranging between 50.24 and 53.16 wt% and MgO fluctuating between 5.22 and 7.90 wt%, comparable to dykes described in other regions of the Cameroon Line (CL). The rocks studied belong to the tholeiitic series and were emplaced in within‐plate basalts (WPB) and mid‐ocean ridge basalts (MORBs) setting. The variations in major and trace elements from the basanite to basaltic andesite compositions are dependable with fractional crystallization (FC) of different mineral phases such as opaque minerals, olivine, clinopyroxene, amphibole and alkali feldspar. Most samples exhibit negative Nb–Ta and positive Sr anomalies, which together with the negative correlation between MgO and 87Sr/86Sr, and isotopic ratio of 206Pb/204Pb <19.5 (18.27–19.49) suggests interactions of crustal components. Nevertheless, this contamination seems limited because there is a positive correlation between SiO2 and 143Nd/144Nd plot and low Ba contents (72–210 ppm) of the samples compared to the mid‐continental crust (259–628 ppm). Trace element modelling proposes a derivation of the Figuil–Léré dykes from parental melts generated by 4%–15% partial melting of a source containing garnet peridotite in the mixed lithospheric–asthenospheric mantle. The isotopic data of the dykes studied with hybrid magma composition are characterized by more radiogenic 87Sr/86Sr, 143Nd/144Nd and 206Pb/204Pb isotopic ratios with a dominant mixing of depleted MORB mantle (DMM)–enriched mantle 1 (EM1)–enriched mantle 2 (EM2), like those of other mafic dykes of the CL.

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Section: Introductionmentioning

confidence: 99%

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Gountié Dedzo,

Klamadji,

Zangmo Tefogoum

et al. 2023

Geological Journal

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“…The formation of basic to intermediate intrusions which very often outcrop in dykes and sills is considered to be a direct consequence of tectonic events that have affected the Pan-African basement (Toteu et al, 1987(Toteu et al, , 1990. In Cameroon, mafic dykes have been studied in southern Cameroon in many localities: 1) Biden in the south-east of Ngaoundéré (Vicat et al, 2001); 2) Mayo Oulo-Léré (Ngounouno et al, 2001); 3) Banganté, Maham, Kendem, Dschang, Bangoua and Manjo (Tchouankoué et al, 2012(Tchouankoué et al, , 2014; 4) Mbaoussi (Nkouandou et al, 2016); 5) Likok (Nkouandou et al, 2015); 6) Mongo in Central Chad (Nkouandou et al, 2017); 7) Temte (Poli) in North Cameroon (Atour et al, 2020); 8) Figuil and Léré (Far North Cameroon and SW of Chad) where these dykes intersect the Pan-African basement (Klamadji et al, 2020). In the Cretaceous sedimentary basins of the study area, straddling Cameroon and Chad (Figuil and Léré), basic intrusions of a doleritic nature have so far not been the subject of a detailed petrological study.…”

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confidence: 99%

Fractional Crystallization and Crustal Contamination of Doleritic and Trachytic Dykes Crosscutting the Cretaceous Sedimentary Basins from Figuil (North Cameroon) and Léré (South-Western Chad): Geodynamic Implications

Klamadji¹,

Dedzo²,

Tchameni³

et al. 2021

GEP

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Magmatism in the Cretaceous sedimentary basins of the Figuil and Léré regions constitutes one of the fundamental parameters in the reconstruction of the history of the Cretaceous sedimentary basins. The main objective of this paper is to constrain the petrogenetic processes of hypovolcanic rocks and to determine their geodynamic context of emplacement. The petrographic study of mafic hypovolcanic and trachytic rocks was carried out under a polarizing microscope on thin sections. For the geochemical study, the major oxides and some trace elements were analyzed by ICP-AES. Trace and rare earth elements were analyzed by ICP-MS. The dolerites of the Cretaceous sedimentary basins are composed of dykes of amphibole bearing dolerites, biotite and pyroxene bearing dolerite, pyroxene bearing dolerites and trachytes. The dykes are in the order of 20 to 100 m wide by several kilometers long and oriented from N23˚E to N90˚E. The textures of these rocks are sub-ophitic to intergranular for dolerites and trachytic for evolved rocks (trachytes). The geochemical study shows that the dolerites are basaltic in composition with alkaline to subalkaline character. The sampled dykes have an evolution dominated by fractional with the minor impact of the crustal assimilation characterized by low Rb/Y ratios for dolerites (0.36 -0.97) and high values of Rb/Y for the Pan-African granitoids' samples (1.95 -4.01). The nature of doleritic and trachytic magma sources is supported by their (Tb/Yb)N > 1.

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Petrography and Major Oxide Geochemistry of Dolerite Dykes from Kunnam Region Villupuram, Tamil Nadu, Southern India

Mohammed,

Ramachandran,

Pitchaimani

et al. 2024

Advances in Geographical and Environmental Sciences

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Petrology and geochemical framework of dolerites dykes of Temté, North Cameroon, Central Africa

Cited by 3 publications

References 37 publications

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Fractional Crystallization and Crustal Contamination of Doleritic and Trachytic Dykes Crosscutting the Cretaceous Sedimentary Basins from Figuil (North Cameroon) and Léré (South-Western Chad): Geodynamic Implications

Petrography and Major Oxide Geochemistry of Dolerite Dykes from Kunnam Region Villupuram, Tamil Nadu, Southern India

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Petrology and geochemical framework of dolerites dykes of Temté, North Cameroon, Central Africa

Cited by 3 publications

References 37 publications

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Major, trace elements and Sr–Nd–Pb isotopes systematics of mafic dykes from the Figuil (northern Cameroon) and Léré (southwestern Chad) areas

Fractional Crystallization and Crustal Contamination of Doleritic and Trachytic Dykes Crosscutting the Cretaceous Sedimentary Basins from Figuil (North Cameroon) and L&#233;r&#233; (South-Western Chad): Geodynamic Implications

Petrography and Major Oxide Geochemistry of Dolerite Dykes from Kunnam Region Villupuram, Tamil Nadu, Southern India

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Fractional Crystallization and Crustal Contamination of Doleritic and Trachytic Dykes Crosscutting the Cretaceous Sedimentary Basins from Figuil (North Cameroon) and Léré (South-Western Chad): Geodynamic Implications