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| Titel |
Influence of the Ringwoodite-Perovskite transition on mantle convection in spherical geometry as a function of Clapeyron slope and Rayleigh number |
| VerfasserIn |
M. Wolstencroft, J. H. Davies |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 2, no. 2 ; Nr. 2, no. 2 (2011-12-19), S.315-326 |
| Datensatznummer |
250000602
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| Publikation (Nr.) |
 copernicus.org/se-2-315-2011.pdf |
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| Zusammenfassung |
| We investigate the influence on mantle convection of the negative Clapeyron slope ringwoodite to
perovskite and ferro-periclase mantle phase transition, which is correlated with the seismic discontinuity
at 660 km depth. In particular, we focus on understanding the influence of the magnitude of the Clapeyron slope
(as measured by the Phase Buoyancy parameter, P) and the vigour of convection (as measured by the Rayleigh number, Ra)
on mantle convection. We have undertaken 76 simulations of isoviscous mantle convection in spherical geometry, varying Ra and P.
Three domains of behaviour were found: layered convection for high Ra and more negative P, whole mantle convection for low Ra
and less negative P, and transitional behaviour in an intervening domain. The boundary between the layered and transitional domain
was fit by a curve P = α Raβ where α = −1.05, and β = −0.1, and the fit for the boundary between the transitional
and whole mantle convection domain was α = −4.8, and β = −0.25. These two curves converge at Ra ≈ 2.5 × 104 (well below Earth mantle vigour) and P ≈ −0.38.
Extrapolating to high Ra, which is likely earlier in Earth history, this work suggests a large transitional domain. It is therefore likely that convection in the
Archean would have been influenced by this phase change, with Earth being at least in the transitional domain, if not the layered domain. |
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