The mantle transition zone (MTZ) discontinuities beneath the Tanzania Craton and the Eastern and Western Branches of the East African Rift System are imaged by stacking over 7,100 receiver functions. The mean thickness of the MTZ beneath the Western Branch and Tanzania Craton is about 252 km, which is comparable to the global average and is inconsistent with the existence of present-day thermal upwelling originating from the lower mantle. In contrast, beneath the Eastern Branch, an up to 30 km thinning of the MTZ is observed and is attributable to upwelling of higher temperature materials from either the upper MTZ or the lower mantle. The observations are in agreement with the hypothesis that rifting in Africa is primarily driven by gradients of gravitational potential energy and lateral variations of basal traction force along zones of significant changes of lithospheric thickness such as the edges of the Tanzania Craton.
M. Sun et al., "Receiver Function Imaging of Mantle Transition Zone Discontinuities Beneath the Tanzania Craton and Adjacent Segments of the East African Rift System," Geophysical Research Letters, vol. 44, no. 24, pp. 12,116-12,124, American Geophysical Union (AGU), Dec 2017.
The definitive version is available at https://doi.org/10.1002/2017GL075485
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Continental rifting; East African Rift System; Mantle plume; Mantle transition zone; Receiver function
International Standard Serial Number (ISSN)
Article - Journal
© 2017 American Geophysical Union (AGU), All rights reserved.
01 Dec 2017