Abstract

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.

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

The study was partially supported by the then Continental Dynamics Program of the U.S. National Science Foundation under grant 1009946 to S.G. and K.L. and by the China Scholarship Council to M.S.

Keywords and Phrases

Continental rifting; East African Rift System; Mantle plume; Mantle transition zone; Receiver function

International Standard Serial Number (ISSN)

0094-8276; 1944-8007

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2017 American Geophysical Union (AGU), All rights reserved.

Included in

Geology Commons

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