The Cameroon Volcanic Line CVL is an enigmatic structure that defies common dynamic models of melt generation and volcanic activity on Earth.
According to the article A lithospheric instability origin for the Cameroon Volcanic Line Milelli et al. The enigma is due to the CVL having no spatial age progression in the rift system, despite having continual magma intrusion over 70 million years along the onshore-offshore line.
The authors also suggest that The chain is nearly perpendicular to the coastline and terminates in a Y-shaped structure that has not been affected by absolute plate motions, implying that the mantle upwelling that feeds magmatic activity is attached to the continent.
The authors model that rather than a developing rift system, the CVL is likely to be an example of where the lithosphere becomes unstable due to cooling from the crust above. It should be noted that the CVL lies in between 2 cratons, shown as white in the seismic tomography image below from Macquarie Universty - what also should be noted, is the colour of the active East African Rift.
Further, according to the article Formation of the Cameroon Volcanic Line by lithospheric basal erosion: Insight from mantle seismic anisotropy Elsheikh et al. The model is consistent with the lack of age progression of the volcanoes in the CVL, can explain the formation of both the continental and oceanic sections of the CVL, and is supported by previous geophysical observations and geodynamic modeling results.
A key conclusion the authors made regarding the flood basalts and volcanism in the CVL is that observations do not support mantle convection or mantle plume causes, rather, they assert that basal lithospheric erosion due to concentration of mantle flow associated with the sharp change in the orientation of the continental margin of western Africa.The Cameroon experiment will evaluate models for the origin of volcanic lines without age progression (hot lines) by examining the seismic structure of the crust and upper mantle beneath one of the most easily accessible hot lines,the Cameroon Volcanic Line (CVL).
The Cameroon Volcanic Line (CVL) is an enigmatic structure that defies common dynamic models of melt generation and volcanic activity on Earth.
Background. The East African Rift System (EARS), the most extensive rifts on the Earth’s surface, and the Cameroon Volcanic Line (CVL) are the two most prominent tectonic features that attract global seismological collaboration in recent years.
Abstract. AbstractThe origin and petrogenesis of the Cameroon Volcanic Line (CVL), composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, heterogeneity, and nature of available data. A Gravity Study of Cameroon, West Africa, and Geodynamical Implications 1~ XH.
Poudjotn Djornani" and Z AIbouy, ORSTOM Bondy, France SUMMARY Gravity data available in Cameroon are used first to compute a new Bouguer anomaly map of Cameroon.
The Cameroon Volcanic Line (CVL) is an enigmatic structure that defies common dynamic models of melt generation and volcanic activity on Earth. There, magma generation and intrusion has been sustained for more than 70 Myr over a km long chain straddling the ocean–continent boundary, with no detectable spatial age progression.