Physical Parameters Controlling Subduction Dynamics and Surface Topography in Self-consistent Global Models of Mantle Convection

Abstract:

Recent advances in numerical modelling allow global models of mantle convection to realistically reproduce the behaviour at convergent plate boundaries (Crameri et al., 2012a). This allows for a more extensive study of subduction that, in contrast to the numerous regional models, incorporates the complete framework of mantle convection.

Here, we focus on different aspects of mantle convection including (i) slab dip variations, (ii) variations in radial mantle viscosity, and (iii) the presence of localised mantle upwellings and discuss their control on the dynamics of Earth-like plate tectonics. Additionally, we present the effect these parameter variations have on measurable quantities like dynamic topography and plate velocity.

The models are calculated by the finite-volume code Stag-YY (e.g., Tackley 2008) using a multi-grid method on a fully staggered grid. Second, the sticky-air method (Matsumoto and Tomoda 1983; Schmeling et al, 2008) is applied and thus approximates a free surface when the sticky-air parameters are chosen carefully (Crameri et al., 2012b).

Overall, this study demonstrates the ability of various parameters to significantly influence both subduction dynamics and surface topography.

REFERENCES

Crameri, F., et al. (2012a), Geophys. Res. Lett., 39(3).

Crameri, F., et al. (2012b), Geophys. J. Int., 189(1).

Matsumoto, T., and Y. Tomoda (1983), J. Phys. Earth, 31(3).

Schmeling, H., et al. (2008), Phys. Earth Planet. Int., 171(1-4).

Tackley, P. J. (2008), Phys. Earth Planet. Int., 171(1-4).