Conman: vectorizing a finite element code for incompressible two-dimensional convection in the Earth's mantle

King, Scott D.; Raefsky, A.; Hager, Bradford H.

doi:10.1016/0031-9201(90)90225-m

Cited by 184 publications

(97 citation statements)

References 4 publications

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“…The finest mesh employed contains 360 × 180 elements with 1 km grid spacing near the tip of the wedge. The finite element approach used here forms also the basis for the free convection code ConMan (King et al, 1990).…”

Section: Contributing Codesmentioning

confidence: 99%

A community benchmark for subduction zone modeling

Keken

Currie

King

et al. 2008

Physics of the Earth and Planetary Interiors

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144

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Section: Contributing Codesmentioning

confidence: 99%

A community benchmark for subduction zone modeling

Keken

Currie

King

et al. 2008

Physics of the Earth and Planetary Interiors

Self Cite

199

144

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“…To track the geochemical evolution of regions of the mantle, we modified ConMan [King et al, 1989] to include passive tracer particles that are continually added and removed. Particles are advected by determining the velocity of each particle at each timestep and integrating using a predictor-corrector method.…”

Section: Geochemical Tracersmentioning

confidence: 99%

Quantifying mixing and age variations of heterogeneities in models of mantle convection: Role of depth‐dependent viscosity

Hunt

Kellogg

2001

J. Geophys. Res.

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Abstract. Using a two-dimensional finite element model of mantle convection containing over a million tracer particles, we examine the effects of depth-dependent viscosity on the rates and patterns of mixing. We sinrelate the processes of recycling crust at subduction zones and the homogenization of recycled material (by dispersion and by melting at mid-ocean ridges). Particles are continually introduced at dowmvellings and destroyed when they either are so thoroughly dispersed that it would be impossible to measure their presence in the geochemical signature of mid-ocean ridges or oceanic islands, or when they are close to spreading centers, at which point melting would "reset" the geochemical clock. A large number of factors influence the flow pattern and thus the rate at which heterogeneities are dispersed by convection. We examine the effect of increasing the viscosity with depth, and determine how both the residence time of heterogeneities and the extent of lateral mixing and exchange between the upper and lower mantle vary with the viscosity profile of the mantle. We determine the particle distribution resulting from convection models with three viscosity profiles: uniform viscosity, a smooth increase of viscosity with depth, and an abrupt jump in viscosity between the upper and lower mantle. We characterize the resulting distribution of heterogeneities in space and time by examining the age distribution of particles and their locations relative to others introduced into the flow at separate downwellings. Mixing rates in the three models are calculated as a function of the number of particles removed from the flow through time. We fbund that an increase of viscosity at depth does not induce age stratification in which older particles stagnate in the lower mantle, and it does not produce an upper layer (the source of mid-ocean ridge basalt) that is well-mixed compared to the deeper regions. However, pronounced lateral heterogeneity is evident in the distribution of particles of different ages and starting locations that is not apparent from the particle positions alone.

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“…We use ConMan, a finite element computer code [King et al, 1990], to solve the advection-diffusion equations for an incompressible, Newtonian fluid on a two dimensional (2-D) grid. We neglect changes in density except in the calculation of the buoyancy forces (the Boussinesq approximation), so that conservation of mass is given by …”

Section: Numerical Modelsmentioning

confidence: 99%

Numerical models of a dense layer at the base of the mantle and implications for the geodynamics of D″

Montague¹,

Kellogg²

2000

J. Geophys. Res.

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Abstract. To investigate the dynamics of the mantle' s D" layer, we explore numerical models of mantle convection which feature a dense basal boundary layer. We use a double-diffusive finite element convection scheme and vary thermal and chemical Rayleigh numbers and properties including viscosity, thermal conductivity, and internal heating. For isoviscous models with heating only from below, the thermal Rayleigh number (Ra) is set at either 106 or 107. The negative chemical buoyancy of a dense layer produces a stable boundary layer when the ratio of chemical to thermal buoyancy (the buoyancy number B) is around 1. For B = 0.5 the layer is unstable, while B = 0.6 may produce a layer which remains stable for long periods, depending on other factors (such as Rayleigh number, layer thickness, and thermal diffusivity of the layer). At high enough Ra, small-scale convection can occur within the layer. Using Ra = 107, we look at changes in layer thickness from 100 to 300 km at two values of B (0.6 and 1). Convection within the layer takes place most easily when the layer has a greater initial thickness. For B = 0.6, the layer is not always continuous along the lower boundary, so convection within the layer does not occur unless the initial thickness is fairly high (300 km). Increasing the thermal diffusivity of the layer (to simulate enrichment in metals) enhances heat conduction across the layer and can suppress internal convection within D". Enhanced conduction also leads to higher plume temperatures. Including internal heating mainly increases the overall heat flow through the mantle, leading to higher surface heat flux. Finally, we examine models with temperaturedependent viscosity and pressure-dependent viscosity using Rayleigh numbers in the range of 107.Convection within the dense layer is enhanced by the relative reduction in viscosity. Our models exhibit only a modest decrease in viscosity (an order of magnitude) but illustrate how a dense, low-viscosity layer interacts with cold, viscous downwellings.

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Conman: vectorizing a finite element code for incompressible two-dimensional convection in the Earth's mantle

Cited by 184 publications

References 4 publications

A community benchmark for subduction zone modeling

A community benchmark for subduction zone modeling

Quantifying mixing and age variations of heterogeneities in models of mantle convection: Role of depth‐dependent viscosity

Numerical models of a dense layer at the base of the mantle and implications for the geodynamics of D″

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