Imperial College London
Alternate

Saskia Goes

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Geophysics
 
 
 
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Contact

 

+44 (0)20 7594 6434s.goes

 
 
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Location

 

4.47Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Civiero:2019:10.1029/2019GC008636,
author = {Civiero, C and Armitage, J and Goes, S and Hammond, JO},
doi = {10.1029/2019GC008636},
journal = {G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences},
pages = {6106--6122},
title = {The seismic signature of upper-mantle plumes: application to the northern East African Rift},
url = {http://dx.doi.org/10.1029/2019GC008636},
volume = {20},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Several seismic and numerical studies proposed that below some hotspots uppermantle plumelets rise from a thermal boundary layer below 660 km depth, fed by a deeper plume source. We recently found tomographic evidence of multiple uppermantle upwellings, spaced by several 100 km, rising through the transition zone below the northern East African Rift. To better test this interpretation, we run 3D numerical simulations of mantle convection for Newtonian and nonNewtonian rheologies, for both thermal instabilities rising from a lower boundary layer, and the destabilisation of a thermal anomaly placed at the base of the box (700800 km depth). The thermal structures are converted to seismic velocities using a thermodynamic approach. Resolution tests are then conducted for the same P and Sdata distribution and inversion parameters as our traveltime tomography. The Rayleigh Taylor models predict simultaneous plumelets in different stages of evolution rising from a hot layer located below the transition zone, resulting in seismic structure that looks more complex than the simple vertical cylinders that are often anticipated. From the wide selection of models tested we find that the destabilisation of a 200°C, 100 km thick thermal anomaly with a nonNewtonian rheology, most closely matches the magnitude, the spatial and temporal distribution of the anomalies below the rift. Finally, we find that for reasonable uppermantle viscosities, the synthetic plume structures are similar in scale and shape to the actual lowvelocity anomalies, providing further support for the existence of uppermantle plumelets below the northern East African Rift.
AU  - Civiero,C
AU  - Armitage,J
AU  - Goes,S
AU  - Hammond,JO
DO  - 10.1029/2019GC008636
EP  - 6122
PY  - 2019///
SN  - 1525-2027
SP  - 6106
TI  - The seismic signature of upper-mantle plumes: application to the northern East African Rift
T2  - G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences
UR  - http://dx.doi.org/10.1029/2019GC008636
UR  - https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GC008636
UR  - http://hdl.handle.net/10044/1/75492
VL  - 20
ER  -
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