HR: 1340h
AN: V33B-1385    [Abstracts]
TI: P- and S-wave Tomography of the Cameroon Volcanic Line Used to Discriminate Between Formation Models
AU: * Larson, A M
EM: alarson@geosc.psu.edu
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802, United States
AU: Nyblade, A
EM: andy@geosc.psu.edu
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802, United States
AU: Wiens, D
EM: doug@mantle.wustl.edu
AF: Washington University, Department of Earth and Planetary Sciences, St. Louis, MO 63130, United States
AU: Tibi, R
EM: tibi@seismo.wustl.edu
AF: Washington University, Department of Earth and Planetary Sciences, St. Louis, MO 63130, United States
AU: Shore, P
EM: patrick@seismo.wustl.edu.edu
AF: Washington University, Department of Earth and Planetary Sciences, St. Louis, MO 63130, United States
AU: Euler, G G
EM: ggeuler@seismo.wustl.edu
AF: Washington University, Department of Earth and Planetary Sciences, St. Louis, MO 63130, United States
AU: Park, Y
EM: ypark@geosc.psu.edu
AF: Pennsylvania State University, Department of Geosciences, University Park, PA 16802, United States
AU: Nnange, J M
EM: nnangejoe@yahoo.com
AF: INSTITUT DE RECHERCHES GEOLOGIQUES ET MINIERES, BP 4110, Yaounde, 78148, Cameroon
AU: Ateba, B
EM: atebs@yahoo.com
AF: INSTITUT DE RECHERCHES GEOLOGIQUES ET MINIERES, BP 4110, Yaounde, 78148, Cameroon
AU: Tabod, C
EM: ctabod@uycdc.uninet.cm
AF: University of Yaounde I, BP 337, Yaounde, 78148, Cameroon
AB: The Cameroon Volcanic Line (CVL) is a 1600km feature traversing both continental Cameroon in west Africa and the offshore islands of Bioko (part of Equatorial Guinea), Sao Tome and Principe, and Annobon (also part of Equatorial Guinea). The CVL is a fairly linear feature, suggestive of the movement of the African plate over a stationary hotspot, but the volcanic rock ages of the CVL range from 42Ma to the present (with present volcanism occurring in the center of the line at Mt. Cameroon), contrary to what would be expected from a stationary hot spot. Several hypotheses have been proposed for the formation of the CVL. One possible explanation has been that there may be a plume rising to the surface along of previously weakened linear zone. In this scenario, the magma may rise sporadically to the surface at different points along the line thereby explaining the apparent lack of age progression. Other suggested models include edge-flow convection from the nearby Congo craton, the existence of multiple plumes, and a leaky transform. The Cameroon Seismic Experiment was deployed in Cameroon from January 2005 to January 2007, with 8 stations active the first year and an additional 24 stations installed in January 2006. The data from the 32 broadband seismometers is currently being used for a body-wave tomography study to study the upper mantle structure beneath Cameroon. Preliminary results from a P- and S-wave travel time tomography show a linear negative velocity anomaly directly beneath the CVL that extends from shallow mantle depths to at least 350km. This finding suggests that the anomaly is not caused by regional flow patterns associated with the Congo craton.
DE: 7203 Body waves
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7270 Tomography (6982, 8180)
DE: 8415 Intra-plate processes (1033, 3615)
DE: 9305 Africa
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting