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MANTLE HETEROGENEITY AND FLOW FROM MULTIDISCIPLINARY DATA
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A thermal model of the mantle can be derived assuming that heterogeneity is due only to temperature anomalies. The “Africa Superplume” uniquely requires an additional high compositional anomaly to also fit geodynamic data (From Simmons et al., 2007. Thermochemical structure and components of the African Superplume. Geophysical Research Letters, 34, l02301, doi:10.1029/2006gl028009)
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Mantle heterogeneity is most commonly shown as seismic velocity anomalies, because seismic waves are the most direct mantle probe, but these static images are difficult to directly translate to mantle flow. More complete tomographic images of the mantle can be derived through joint inversion of seismic data and a suite of convection-related observations, including surface gravity and topography, core-mantle boundary topography, and tectonic plate divergences, interpreted with viscous-flow response functions and mineral physics constraints. Temperature variations dominate shear-wave and density heterogeneity in the non-cratonic mantle, but notable compositional anomalies are evident, most strongly within the “African Superplume.” Time-dependent flow calculations from the jointly derived density models suggest that even minor compositional anomalies play an important dynamic role, not just beneath the African plate, but also in anomalous flow
patterns that coincide with the New Madrid Seismic Zone, the Colorado Plateau, and other tectonic features.</p>

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