TY - JOUR
T1 - Instability of the African large low-shear-wave-velocity province due to its low intrinsic density
AU - Yuan, Qian
AU - Li, Mingming
N1 - Funding Information:
We are grateful to the extensive discussions and comments on the manuscript by E. Garnero. We also thank K. Hosseini for SubMachine datasets and Y. Wang and S. Yu for valuable comments. The numerical models were performed on the Agave cluster at Arizona State University. Both Q.Y. and M.L. are supported by National Science Foundation grant numbers EAR-1849949 and EAR-1855624.
Funding Information:
We are grateful to the extensive discussions and comments on the manuscript by E. Garnero. We also thank K. Hosseini for SubMachine datasets and Y. Wang and S. Yu for valuable comments. The numerical models were performed on the Agave cluster at Arizona State University. Both Q.Y. and M.L. are supported by National Science Foundation grant numbers EAR-1849949 and EAR-1855624.
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2022/4
Y1 - 2022/4
N2 - Seismic observations have revealed two seismic anomalies in the lowermost mantle, one beneath Africa and the other beneath the Pacific Ocean, named large low-shear-wave-velocity provinces. These structures are generally considered to be intrinsically dense thermochemical piles that influence mantle and core processes. However, the controls on their morphology, including their relative height difference and their stability, remain unclear. Here we analyse published global shear-wave tomography models, which show that the African anomaly is about 1,000 km greater in height than the Pacific anomaly. With our numerical simulations, we find that the maximum height a thermochemical pile can reach is more controlled by its density and the surrounding mantle viscosity, and less so by its own viscosity and volume. Comparing these findings suggests that the African anomaly has a relatively lower density and thus may be less stable than the Pacific anomaly, implying the two anomalies have different compositions, dynamics and evolution histories.
AB - Seismic observations have revealed two seismic anomalies in the lowermost mantle, one beneath Africa and the other beneath the Pacific Ocean, named large low-shear-wave-velocity provinces. These structures are generally considered to be intrinsically dense thermochemical piles that influence mantle and core processes. However, the controls on their morphology, including their relative height difference and their stability, remain unclear. Here we analyse published global shear-wave tomography models, which show that the African anomaly is about 1,000 km greater in height than the Pacific anomaly. With our numerical simulations, we find that the maximum height a thermochemical pile can reach is more controlled by its density and the surrounding mantle viscosity, and less so by its own viscosity and volume. Comparing these findings suggests that the African anomaly has a relatively lower density and thus may be less stable than the Pacific anomaly, implying the two anomalies have different compositions, dynamics and evolution histories.
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U2 - 10.1038/s41561-022-00908-3
DO - 10.1038/s41561-022-00908-3
M3 - Article
AN - SCOPUS:85126022417
SN - 1752-0894
VL - 15
SP - 334
EP - 339
JO - Nature Geoscience
JF - Nature Geoscience
IS - 4
ER -