Lithospheric instability and the source of the Cameroon Volcanic Line

Evidence from Rayleigh wave phase velocity tomography

Aubreya N. Adams, Douglas A. Wiens, Andrew Arnold Nyblade, Garrett G. Euler, Patrick J. Shore, Rigobert Tibi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1708-1727
Number of pages20
JournalJournal of Geophysical Research: Solid Earth
Volume120
Issue number3
DOIs
StatePublished - Mar 1 2015

Fingerprint

Cameroon
Rayleigh waves
Phase velocity
phase velocity
Rayleigh wave
tomography
Tomography
wave velocity
craton
volcanology
velocity structure
S-wave
upper mantle
Shear waves
continental lithosphere
cratons
hot spot
infiltration
plume
convection

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Adams, Aubreya N. ; Wiens, Douglas A. ; Nyblade, Andrew Arnold ; Euler, Garrett G. ; Shore, Patrick J. ; Tibi, Rigobert. / Lithospheric instability and the source of the Cameroon Volcanic Line : Evidence from Rayleigh wave phase velocity tomography. In: Journal of Geophysical Research: Solid Earth. 2015 ; Vol. 120, No. 3. pp. 1708-1727.
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Lithospheric instability and the source of the Cameroon Volcanic Line : Evidence from Rayleigh wave phase velocity tomography. / Adams, Aubreya N.; Wiens, Douglas A.; Nyblade, Andrew Arnold; Euler, Garrett G.; Shore, Patrick J.; Tibi, Rigobert.

In: Journal of Geophysical Research: Solid Earth, Vol. 120, No. 3, 01.03.2015, p. 1708-1727.

Research output: Contribution to journalArticle

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