The Cameroon Line: A Review

Dennielou, Bernard; Moreau, Christian; Nkoumbou, C.; Kambou, Robert; Lissom, Justin; Njonfang, Emmanuel; Ghogomu, R.T.; Nono, Alexandre

doi:10.1007/978-3-642-73966-8_12

Cited by 142 publications

(138 citation statements)

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“…Sr and Nd isotopic studies yield similar results for both the continental and oceanic volcanic centers, suggesting that volcanics in both sectors came from the same sublithospheric source [Déruelle et al 2007]. Ultramafic xenoliths are found in multiple locations in the CVL, further strengthening the case for a mantle source of the CVL volcanics [e.g., Déruelle et al, 1991;Princivalle et al, 2000;Déruelle et al, 2007].…”

Section: The Cameroon Volcanic Linementioning

confidence: 73%

“…The earliest igneous activity associated with the CVL consisted of the intrusion of more than 60 alkaline plutonic ring complexes 66-30 Ma [Déruelle et al, 1991[Déruelle et al, , 2007. Volcanism in the continental CVL began 42 Ma, while offshore volcanic activity initiated 30 Ma and is interpreted to be synchronous with the uplift of the crustal arch [Grunau et al, 1975;Meyers and Rosendahl, 1991;Meyers et al, 1998].…”

Section: The Cameroon Volcanic Linementioning

confidence: 99%

“…At all subcrustal depths, velocities beneath the CVL are slower than the background, showing no evidence for typically seismically fast lithospheric mantle beneath most of the CVL. Geochemical evidence from isotopic studies [Déruelle et al, 2007] and studies of mantle xenoliths [Déruelle et al, 1991;Princivalle et al, 2000;Déruelle et al, 2007] indicate that CVL volcanics are sourced from the sublithospheric mantle. This geochemical evidence for sublithospheric melt, together with the slow velocities that extend to the base of the crust beneath the main branch of the CVL, indicates that the lithospheric mantle has likely been eroded or highly altered beneath the main branch of the CVL and has to a lesser extent been thinned beneath the northern branch of the CVL.…”

Section: Lithospheric Instabilitymentioning

confidence: 99%

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Lithospheric instability and the source of the Cameroon Volcanic Line: Evidence from Rayleigh wave phase velocity tomography

et al. 2015

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The Cameroon Volcanic Line (CVL) is a 1800 km long volcanic chain, extending SW-NE from the Gulf of Guinea into Central Africa, that lacks the typical age progression exhibited by hot spot-related volcanic tracks. This study investigates the upper mantle seismic structure beneath the CVL and surrounding regions to constrain the origin of volcanic lines that are poorly described by the classic plume model. Rayleigh wave phase velocities are measured at periods from 20 to 182 s following the two-plane wave methodology, using data from the Cameroon Seismic Experiment, which consists of 32 broadband stations deployed between 2005 and 2007. These phase velocities are then inverted to build a model of shear wave velocity structure in the upper mantle beneath the CVL. Results show that phase velocities beneath the CVL are reduced at all periods, with average velocities beneath the CVL deviating more than -2% from the regional average and +4% beneath the Congo Craton. This distinction is observed for all periods but is less pronounced for the longest periods measured. Inversion for shear wave velocity structure indicates a tabular low velocity anomaly directly beneath the CVL at depths of 50 to at least 200 km and a sharp vertical boundary with faster velocities beneath the Congo Craton. These observations demonstrate widespread infiltration or erosion of the continental lithosphere beneath the CVL, most likely caused by mantle upwelling associated with edge-flow convection driven by the Congo Craton or by lithospheric instabilities that develop due to the nearby edge of the African continent.

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Section: The Cameroon Volcanic Linementioning

confidence: 73%

Section: The Cameroon Volcanic Linementioning

confidence: 99%

Section: Lithospheric Instabilitymentioning

confidence: 99%

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Lithospheric instability and the source of the Cameroon Volcanic Line: Evidence from Rayleigh wave phase velocity tomography

et al. 2015

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“…Structural tectonic activity started with plutonic and metamorphic phases linked to the Pan African Orogeny during the Cambrian period (540 Ma) when gneisses and granites were emplaced [21][22][23]. The CVL, that was emplaced later, starting at 52 Ma, consists of a series of volcanoes which are separated by plains or low lying areas corresponding to collapsed grabens such as: Tombel, Mbo, Noun, and Tikar [3,[5][6][7][8][9][10]. Ndop (this paper) is somewhat different as it is a low lying plain.…”

Section: Geological Outlines Tectonic and Morphological Evolutionmentioning

confidence: 99%

“…1). The CVL is interpreted as a mega shear zone that seems to be structurally subdivided into an important network of faults associated with a system of alternating horsts and grabens [2][3][4][5][6][7]. The morphological formations of numerous plains all along the CVL have been discussed by [8,9] and [10].…”

Section: Introductionmentioning

confidence: 99%

Geohazards (floods and landslides) in the Ndop plain, Cameroon volcanic line

et al. 2016

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Abstract:The Ndop Plain, located along the Cameroon Volcanic Line (CVL), is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually) and landslides (occasionally) occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people) tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide) maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered. The hazard maps revealed that 25% of the area is exposed to flood hazard (13% exposed to high flood hazard, 12% to moderate) and 5% of the area is exposed to landslide hazard (2% exposed to high landslide hazard, 3% to moderate). Some mitigation measures for floods (building of artificial levees, raising foundations of buildings and the meticulous regulation of the flood guards at Bamendjing Dam) and landslides (slope terracing, planting of trees, and building retaining walls) are proposed.

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Late Cretaceous intraplate silicic volcanic rocks from the Lake Chad region: An extension of the Cameroon volcanic line?

Shellnutt

Lee

Torng³

et al. 2016

Geochem Geophys Geosyst

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Silicic volcanic rocks at Hadjer el Khamis, near Lake Chad, are considered to be an extension of the Cameroon volcanic line (CVL) but their petrogenetic association is uncertain. The silicic rocks are divided into peraluminous and peralkaline groups with both rock types chemically similar to within‐plate granitoids. In situ U/Pb zircon dating yielded a mean 206Pb/238U age of 74.4 ± 1.3 Ma indicating the magmas erupted ∼10 million years before the next oldest CVL rocks (i.e., ∼66 Ma). The Sr isotopes (i.e., ISr = 0.7021–0.7037) show a relatively wide range but the Nd isotopes (i.e., 143Nd/144Ndi = 0.51268–0.51271) are uniform and indicate that the rocks were derived from a moderately depleted mantle source. Thermodynamic modeling shows that the silicic rocks likely formed by fractional crystallization of a mafic parental magma but that the peraluminous rocks were affected by low temperature alteration processes. The silicic rocks are more isotopically similar to Late Cretaceous basalts identified within the Late Cretaceous basins (i.e., 143Nd/144Ndi = 0.51245–0.51285) of Chad than the uncontaminated CVL rocks (i.e., 143Nd/144Ndi = 0.51270–0.51300). The age and isotopic compositions suggest the silicic volcanic rocks of the Lake Chad region are related to Late Cretaceous extensional volcanism in the Termit basin. It is unlikely that the silicic volcanic rocks are petrogenetically related to the CVL but it is possible that magmatism was structurally controlled by suture zones that formed during the opening of the Central Atlantic Ocean and/or the Pan‐African Orogeny.

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The Cameroon Line: A Review

Cited by 142 publications

References 0 publications

Lithospheric instability and the source of the Cameroon Volcanic Line: Evidence from Rayleigh wave phase velocity tomography

Lithospheric instability and the source of the Cameroon Volcanic Line: Evidence from Rayleigh wave phase velocity tomography

Geohazards (floods and landslides) in the Ndop plain, Cameroon volcanic line

Late Cretaceous intraplate silicic volcanic rocks from the Lake Chad region: An extension of the Cameroon volcanic line?

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