Geodynamics

Geodynamics studies the forces driving tectonics by integrating atmosphere, surface and deep Earth processes. At Getech, we have focussed on building the following observational databases which are the consequence of geodynamics: the Global Plate Model, palaeolandscape maps, ocean age, crustal architecture and structural and tectonic evolution. We are now starting to investigate the geodynamic processes responsible for these observations and how this understanding can be used to refine our interpretations.

Geodynamics research considers all aspects of Earth evolution to better understand our planet. Geodynamics considers the interaction of processes from atmosphere to crust and lithosphere to the deep Earth interior. Interaction between disciplines improves understanding of individual systems and Earth as a whole. Deep Earth and atmospheric processes influence both horizontal and vertical motions of the surface, including plate motions and the evolution of topography.

Geodynamics links to Getech’s Global Plate Model and crustal architecture by analysing the driving forces acting on the lithosphere to drive global tectonics and the mechanisms for breaking up (super)continents and passive margin formation.

Vertical motion of the surface, including that arising from mantle convection, influences plate motions, petroleum systems and sea level. Geodynamics also considers how plate kinematics affects the mantle convection and ocean circulation systems.

Possible dynamic contribution to Earth’s topography calculated from mantle circulation models. (a) including density variations from the whole mantle. Continents are ‘depressed’ as they are stable and cold for long periods of time. Near surface process contribute to the elevation of oceanic crust. (b) density variations in the upper 300 km of mantle are set to zero. This predicts long wavelength, broadly degree 2 pattern dynamic topography, suggesting a link to deep Earth processes.

Possible dynamic contribution to Earth’s topography calculated from mantle circulation models. (a) including density variations from the whole mantle. Continents are ‘depressed’ as they are stable and cold for long periods of time. Near surface processes contribute to the elevation of oceanic crust. (b) density variations in the upper 300 km of mantle are set to zero. This predicts long wavelength, broadly degree 2 pattern dynamic topography, suggesting a link to deep Earth processes.

Isostasy alone cannot explain Earth’s observed topography. An additional component created by convection processes in the deep Earth, known as dynamic topography, is important for understanding tectonic and landscape evolution and sea level changes. Dynamic topography links whole mantle convection to surface processes on a number of scales. Large scale, stable lower mantle features produce sustained dynamic elevation in areas (such as southern Africa) which have been unaffected by mountain building processes in the recent geological past.

More transient, shallower convection patterns also produce smaller scale dynamic topography with changes on timescales of a few million years.

Feedback from earth system modelling and climate studies also contribute to geodynamic studies. Configuration of the continents affects global ocean circulation and climate belts, whilst glaciation affects the rate of erosion and the isostatic response. Integration of many disciplines is required to understand the mechanisms for horizontal and vertical motions of Earth’s crust.

Example of ‘dynamic’ and ‘tectonic’ topography. In (a) positive elevations are caused by hot material upwelling from the lower mantle and negative elevations from subducting material sinking to depth. In (b) plate tectonic processes thin or thicken the lithosphere, altering crustal thickness and therefore topography. From Braun (2010) Nat. Geosci.

Example of ‘dynamic’ and ‘tectonic’ topography. In (a) positive elevations are caused by hot material upwelling from the lower mantle and negative elevations from subducting material sinking to depth. In (b) plate tectonic processes thin or thicken the lithosphere, altering crustal thickness and therefore topography. From Braun (2010) Nat. Geosci.

To find out more about Getech’s Geodynamics Expertise, please contact us at info@getech.com.