Elemental and Sr–Nd–Pb isotopic compositions, and K–Ar ages of transitional and alkaline plateau basalts from the eastern edge of the West Cameroon Highlands (Cameroon Volcanic Line)

Lemdjou, Yanick Brice; Zhang, Da; Tchouankoue, Jean Pierre; Hu, Jiaxiu; Ngongang, Nicaise Blaise Tchuimegnié; Tamehe, Landry Soh; Yuan, Yuan

doi:10.1016/j.lithos.2020.105414

Cited by 6 publications

(6 citation statements)

References 75 publications

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“…The Nb/U ratio in primary mantle-derived magma is always greater than 47, and the La/Nb and La/Ta ratios are always smaller than 1.5 and 22, respectively. These ratios can be used to identify the existence of crustal material due to their sensitivity to crustal contamination [62][63][64]. The Nb/U ratio in the GAAB was much higher than crustal material, but close to mantle-derived values.…”

Section: Petrogenesismentioning

confidence: 60%

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

Shang

Chen

2020

Minerals

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The Gejiu Anisian alkaline basalts (GAAB), distributed in the southern part of the Emeishan large igneous province (ELIP), are crucial to understand the tectonomagmatic activity during the Triassic. Geochronological, geochemical, and Sr-Nd-Pb isotopic analyses were systematically applied to explore the origin, petrogenesis, and tectonic setting of the GAAB, and how they relate to the ELIP. Zircon U-Pb dating set the eruption date at 244 Ma. Most of the samples belonged to alkaline basalts and had high TiO2 (2.14–3.23 wt.%) and MgO (4.43–19.58 wt.%) contents. Large ion lithophile elements (LILEs) were enriched relative to high field strength elements (HFSEs). The rare earth elements (REEs) and trace element signatures in the normalized diagrams were similar to oceanic island basalts (OIB) and Emeishan high-Ti basalts. These samples had consistent Sr-Nd isotope compositions: the initial 87Sr/86Sr values ranged from 0.7044 to 0.7048 and εNd(t) = 3.25–4.92. The Pb isotopes were more complex, the (206Pb/204Pb)t, (207Pb/204Pb)t, (208Pb/204Pb)t ratios were 17.493–18.197, 15.530–15.722, and 37.713–38.853, respectively. Our results indicate that the GAAB originated from the deeper enriched mantle with 5% to 15% partial melting of garnet lherzolite and a segregation depth of 2 to 4 GPa (60–120 km). During the formation of the GAAB, clinopyroxene and Ti-Fe oxides were fractionally crystallized with insignificant crustal contamination. The GAAB were formed in a extensional regime that was related to the Gejiu-Napo rift event in the Triassic.

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Section: Petrogenesismentioning

confidence: 60%

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

Shang

Chen

2020

Minerals

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“…The initial ratios were calculated based on mean K–Ar age data of 65 Ma (mean of 43 and 87 Ma; Wilson & Guiraud, 1998) and 231.1 Ma (Aka et al, 2018) for dolerite of Cretaceous sedimentary basin (DCSB) and dolerite of Pan‐African basement (DPB) samples, respectively. Literature data for other Cameroon Line (CL) dykes are from Asaah et al (2022) and those from Cameroon Volcanic Line (CVL) lavas are obtained from Asaah et al (2015), Lemdjou et al (2020), Wembenyui et al (2020) and Asaah et al (2021).…”

Section: Resultsmentioning

confidence: 99%

“…Trace elements or the proportion of isotopic data also fluctuated in the source of the dykes with the magmatism of CVL. Compared to CVL lavas ( 87 Sr/ 86 Sr = 0.7033, 143 Nd/ 144 Nd = 0.5129 and 206 Pb/ 204 Pb = 19.85; Asaah et al, 2015, 2021; Gountié Dedzo et al, 2019; Lemdjou et al, 2020; Wembenyui et al, 2020), the DPB and DGCSB dykes of Figuil–Léré are radiogenic in 87 Sr/ 86 Sr (i) (mean: 0.7047 and 0.7038, respectively), unradiogenic in 143 Nd/ 144 Nd (i) (mean: 0.5125 and 0.5128, respectively) and 206 Pb/ 204 Pb (i) (mean: 18.85 and 19.9, respectively) as other studied dykes of CL (Asaah et al, 2022). As the trace elements have already demonstrated, the mixing between the asthenospheric magma and the crustal components is also highlighted by the isotopic ratios of some studied dykes.…”

Section: Discussionmentioning

confidence: 99%

“…The depth of melting can be also assessed by trace elements ratios (Putirka, 1999;Zheng et al, 2003). The low Ce/Yb ratios of most DGCSB dyke samples (9.50-13.35) suggest that their magma formed Asaah et al, 2015Asaah et al, , 2021Gountié Dedzo et al, 2019;Lemdjou et al, 2020;Wembenyui et al, 2020), the DPB and DGCSB dykes of Figuil-Léré are radiogenic in 87 Sr/ 86 Sr (i) (mean: 0.7047 and 0.7038, respectively), unradiogenic in 143 Nd/ 144 Nd (i) (mean: 0.5125 and 0.5128, respectively) and 206 Pb/ 204 Pb (i) (mean: 18.85 and 19.9, respectively) as other studied dykes of CL (Asaah et al, 2022).…”

Section: Crustal Contamination Processmentioning

confidence: 99%

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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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“…These tertiary basalts occur as prismatic columnar lava flow at a mean altitude of 1400 m and dominantly consist of 3 -14 Ma alkaline and 36 -47 Ma transitional basalts [21] [22] [23] [24]. Both basalts are the product of the interaction between mantle upwelling and sublithospheric continental during a lithospheric extensional tectonic setting [22] [25].…”

Section: Geological Backgroundmentioning

confidence: 99%

Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Ndé Division, West-Cameroon (Central Africa)

Feumba¹,

Tchouta²,

Youmbi³

et al. 2021

JWARP

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Ndé Division in West-Cameroon is facing with water supply although many attempts of restoring existing SCANWATER facilities by Bangangté Municipality. In order to address the issue, we assess the exploitable pumping flow rate of catchment aquifers and its hydraulic properties by using Jacob and Theis method, and define protection zones with Hoffman and Lillich method. It emerges that the hydraulic conductivity of aquifer is in the order of 10 −4 m/sec, transmissivity varies from 10 −4 to 10 −6 m 2 /sec. Aquifer pumping flow rate (Q) varies between 1.5 and 10.5 m 3 /h. In volcanic rocks, aquifer is more productive (4.5 ≤ Q ≤ 10.5 m 3 /h). Transfer time of pollutants to aquifer varies from 3 to 56 days depending on rock-types and groundwater slope (0.03 -0.13 m/m). Furthermore, 113,624 m and 1123 m are radius to be implemented for a better protection of groundwater against any form of pollutant.

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Elemental and Sr–Nd–Pb isotopic compositions, and K–Ar ages of transitional and alkaline plateau basalts from the eastern edge of the West Cameroon Highlands (Cameroon Volcanic Line)

Cited by 6 publications

References 75 publications

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

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

Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Ndé Division, West-Cameroon (Central Africa)

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Elemental and Sr–Nd–Pb isotopic compositions, and K–Ar ages of transitional and alkaline plateau basalts from the eastern edge of the West Cameroon Highlands (Cameroon Volcanic Line)

Cited by 6 publications

References 75 publications

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

Zircon U–Pb Geochronology, Geochemistry and Geological Significance of the Anisian Alkaline Basalts in Gejiu District, Yunnan Province

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

Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Nd&#233; Division, West-Cameroon (Central Africa)

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Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Ndé Division, West-Cameroon (Central Africa)