Relationship between mantle convection and lithosphere dynamics on Earth, Moon and Planets: GFZ

Figure: observed plate motions — Figure 1: Observed plate motions (a, and blue arrows in c and d), model results with plate boundary friction coefficient 0.02 (b, and red arrows ind c), and with friction coefficient 0.0121 at subduction zones and 0.0219 at remaining boundaries. Asthenosphere minimum viscosity cutoff 1020 Pas. For more details, see Osei Tutu et al. (in revision). Figure created by Anthony Osei Tutu. *(Osei Tutu et al. (in revision))*

Abbildung: Amplitude spectra — Figure 2: Amplitude spectra for observed and modelled dynamic topography. *(.)*

Relationship between mantle convection and lithosphere dynamics on Earth, Moon and Planets

Mantle convection provides the driving forces for tectonic plate motions on Earth. By striving for the best possible match between numerical model results and observation data (Figure 1), we constrain plate boundary friction and asthenosphere viscosity (Osei Tutu et al., in press). We also model lithospheric stresses (Osei Tutu et al., 2017), vertical deflection of the lithosphere – so-called dynamic topography (Steinberger, 2016) and the geoid (Ghosh et al., 2017), which all can be compared to observations. An important ingredient of such models is lithosphere thickness (Steinberger and Becker, 2016). A big discrepancy exists for dynamic topography at spherical harmonic degree two: The model predicts much larger amplitude than observed, due to density anomalies in the lower mantle (Steinberger et al, in press; Figure 2). We extend our models to other terrestrial bodies, such as the Moon (Steinberger et al., 2015) to improve our knowledge about interior structure and processes. We are also interested in how dynamic topography may influence surface processes. For example, we have developed a scenario how hot material sourced in the Iceland plume has uplifted eastern Greenland, and this process, together with northward motion of Greenland due to both plate motions and true polar wander, has been a contributing factor to the onset of northern hemisphere glaciations (Steinberger et al., 2015).

Ph. D. Student:

Anthony Osei Tutu

External collaborations:

Selected recent publications:

Osei Tutu, A., Steinberger, B., Sobolev, S. V., Rogozhina, I., and Popov, A. A. (2017): Effects of upper mantle heterogeneities on lithospheric stress field and dynamic topography, Solid Earth Discuss, doi.org/10.5194/se-2017-111.
Osei Tutu, A., Steinberger, B., Rogozhina, I., and Sobolev, S.V.: Evaluating the influence of plate boundary friction and mantle viscosity on plate velocities. - Geochemistry Geophysics Geosystems, in press.
Steinberger, B., Conrad, C.P., Osei Tutu, A., and Hoggard, M.J.: On the amplitude of dynamic topography at spherical harmonic degree two. - Tectonophysics, in press.
Ghosh, A., Thyagarajulu, G., and Steinberger, B. (2017): The importance of upper mantle heterogeneity in generating the Indian Ocean geoid low. - Geophysical Research Letters, 44, 9707–9715.
Steinberger, B., Becker, T. (2016 online): A comparison of lithospheric thickness models. - Tectonophysics.
Steinberger, B. (2016): Topography caused by mantle density variations: observation-based estimates and models derived from tomography and lithosphere thickness. - Geophysical Journal International, 205, 1, p. 604-621.
Steinberger, B., Zhao, D., Werner, S. C. (2015): Interior structure of the Moon: Constraints from seismic tomography, gravity and topography. - Physics of the Earth and Planetary Interiors, 245, p. 26-39.
Steinberger, B., Spakman, W., Japsen, P., Torsvik, T. H. (2015): The key role of global solid-Earth processes in preconditioning Greenland's glaciation since the Pliocene. - Terra Nova, 27, 1, p. 1-8.

Selected press coverage and popular science:

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