Geophysical Research Letters · 2000 · 114 citations · 16 references
Natural SciencesEarth SciencesGeophysicsSeismologyTectonicsVolcanologyMantle SeismologyPlate TectonicsRegional TectonicsRift StructuresRift TectonicsSubduction Zone TectonicsContinental TectonicsEast African Rift SystemPlateau UpliftRift FaultingRift TopographyRift-related FaultingStackingTransition Zone Structure
The study aims to determine relative variations in the thickness of the mantle transition zone beneath Tanzania. This is achieved by applying a three‑dimensional stacking method to receiver functions from the Tanzania Broadband Seismic Experiment. The transition zone under the Eastern rift is 30–40 km thinner than in the interior of the East African Plateau, extending several hundred kilometres and coinciding with a 2–3 % reduction in S‑wave velocities, which can be attributed to a 200–300 K temperature increase that suggests a plume origin for Cenozoic rifting, volcanism, and plateau uplift.
We apply a three‐dimensional stacking method to receiver functions from the Tanzania Broadband Seismic Experiment to determine relative variations in the thickness of the mantle transition zone beneath Tanzania. The transition zone under the Eastern rift is 30–40 km thinner than under areas of the Tanzania Craton in the interior of the East African Plateau unaffected by rift faulting. The region of transition zone thinning under the Eastern rift is several hundred kilometers wide and coincides with a 2–3% reduction in S wave velocities. The thinning of the transition zone, as well as the reduction in S wave velocities, can be attributed to a 200–300°K increase in temperature. This thermal anomaly at >400 km depth beneath the Eastern rift cannot be easily explained by passive rifting and but is consistent with a plume origin for the Cenozoic rifting, volcanism and plateau uplift in East Africa.
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Paul Wessel, Walter H. F. Smith · Eos · 1991 · 4.1K citations