Physics of Mantle Convection

Ricard, Yanick

doi:10.1016/b978-044452748-6.00115-2

Cited by 43 publications

(37 citation statements)

References 222 publications

(149 reference statements)

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“…Whether the a g c part of the buoyancy force can be ignored without making a significant error is an open question; see, for example, x7.02.2.5.2 of Ricard (2007). Braginsky and Roberts (1995) pointed out that, by a minor modification to the definitions of c and p c , a variant of (14) holds even when a g c is retained in (12b).…”

Section: Overview Of Core Dynamicsmentioning

confidence: 97%

On the theory of core-mantle coupling

Roberts

Aurnou

2012

Geophysical & Astrophysical Fluid Dynamics

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Section: Overview Of Core Dynamicsmentioning

confidence: 97%

On the theory of core-mantle coupling

Roberts

Aurnou

2012

Geophysical & Astrophysical Fluid Dynamics

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“…Due to convective stresses, the free surface of a liquid is slightly deformed, to a ''depth'' z52hðx; y; tÞ, much smaller than the fluid thickness, and the normal n to the surface is not strictly vertical [see also Ricard, 2007]. The topography hðx; y; tÞ is often called in the geophysical literature ''dynamic'' topography (i.e., not related to the Moho undulations).…”

Section: Surface Boundary Conditions On Top Of a Convective Fluidmentioning

confidence: 99%

Lifting the cover of the cauldron: Convection in hot planets

Ricard

Labrosse

Dubuffet

2014

Geochem Geophys Geosyst

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Convection models of planetary mantles do not usually include a specific treatment of nearsurface dynamics. In all situations where surface dynamics is faster than internal dynamics, the lateral transport of material at the surface forbids the construction of a topography that could balance the internal convective stresses. This is the case if intense erosion erases the topography highs and fills in the depressions or if magma is transported through the lithosphere and spreads at the surface at large distances. In these cases, the usual boundary condition of numerical simulations, that the vertical velocity cancels at the surface should be replaced by a condition where the vertical flux on top of the convective mantle equilibrates that allowed by the surface dynamics. We show that this new boundary condition leads to the direct transport of heat to the surface and changes the internal convection that evolves toward a heat-pipe pattern. We discuss the transition between this extreme situation where heat is transported to the surface to the usual situation where heat diffuses through the lithosphere. This mechanism is much more efficient to cool a planet and might be the major cooling mechanism of young planets. Even the modest effect of material transport by erosion on Earth is not without effect on mantle convection and should affect the heat flow budget of our planet.

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“…The velocities in eqs (1)-(4) are determined by Darcy's law and a momentum or force balance equation (e.g. McKenzie 1984;Scott & Stevenson 1986;Fowler 1990;Spiegelman 1993;Schmeling 2000;Bercovici et al 2001;Ricard 2009). When the solid flow field is irrotational and the shear viscosity of the solid is constant and uniform, Darcy's law can be written in terms of gradients of an effective pressure and melt buoyancy,…”

Section: G Ov E R N I N G E Q Uat I O N S a N D S E T U Pmentioning

confidence: 99%

“…Scott & Stevenson 1986;Sleep 1988;Fowler 1985Fowler , 1990Schmeling 2000;Bercovici et al 2001;Connolly & Podladchikov 2007;Šrámek. et al 2007;Hewitt & Fowler 2008;Ricard 2009;Hewitt 2010;Simpson et al 2010). The effective pressure can be solved from a Helmholtz equation obtained by combining eqs (1) and (2) and the divergence of eq.…”

Section: G Ov E R N I N G E Q Uat I O N S a N D S E T U Pmentioning

confidence: 99%

A high-order numerical study of reactive dissolution in an upwelling heterogeneous mantle—I. Channelization, channel lithology and channel geometry

Schiemenz

Liang

Parmentier

2011

Geophysical Journal International

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S U M M A R YHigh-porosity channels are important pathways for melt migration in the mantle. To better understand the lithology and geometry of high-porosity melt channels, we conduct highorder accurate numerical simulations of reactive dissolution along a solubility gradient in an upwelling and viscously deformable porous column. In contrast to earlier studies, we assume the dissolution reaction to be at equilibrium, consider a finite soluble mineral abundance, and employ a high-order accurate numerical scheme. Using sustained perturbations in porosity and soluble mineral abundance at the inflow boundary, we explore the structure of steadystate high-porosity melt channels and their associated lithologies over a range of parameters, including soluble mineral abundance, solubility gradient, amplitude and lateral variation in inflow melt flux, melt fraction and upwelling rate. In general, high-porosity dunite channels are transient and shallow parts of pathways for melt migration in the mantle. The lower parts of a high-porosity channel are orthopyroxene-bearing dunite, harzburgite and possibly lherzolite. A wide orthopyroxene-free dunite channel may contain two or three high-porosity melt channels. The depth of dunite channel initiation depends on the solubility gradient, soluble mineral abundance, inflow melt flux, melt suction rate and upwelling rate. The amplitude and length scale of lateral variation in porosity and orthopyroxene abundance at the base of the upwelling column are important in determining the size and dimension of dunite channels, the strength of melt focusing and the melt suction rate, the presence of compacting boundary layer, as well as the number of high-porosity melt branches within a dunite channel. The spatial relations among the high-porosity melt channels, dunite and harzburgite channels documented in our numerical simulations may shed new light on a number of field, petrological and geochemical observations related to melt migration in the mantle.

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Physics of Mantle Convection

Cited by 43 publications

References 222 publications

On the theory of core-mantle coupling

On the theory of core-mantle coupling

Lifting the cover of the cauldron: Convection in hot planets

A high-order numerical study of reactive dissolution in an upwelling heterogeneous mantle—I. Channelization, channel lithology and channel geometry

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