Plate motions continuously reshape the surface of the Earth: mountains rise where plates converge and rifts open up where they move apart. Plate tectonic theory attempts to describe this dynamic evolution of the outer shell of the Earth in terms of lithospheric plates. These plates are the interface between the mantle and the Earth’s outer layers (the oceans and atmosphere); they record mantle-lithosphere interactions through time, including massive LIP volcanic events. Conversely, movement of the plates affect the evolution of oceans, biodiversity and long-term climate.
Wilson Cycles, Mantle Plumes and Climate
It was not until Wilson’s classic paper Did the Atlantic close and then re-open? (Nature 211, 676 – 681, 1966) that plate tectonic processes were understood to have been operating before Pangea. Wilson’s succession of rifting, crustal subsidence and ocean opening, subduction initiation and ocean closure, and finally continent-continent collision was termed the ‘Wilson Cycle’ by CEED collaborator K. Burke. The ‘Wilson Cycle’ concept also spurred an intensive search for older supercontinents — As many as five supercontinents have now been proposed and there may be a periodicity of ~500 Myr for their formation.
Greenhouse climate (warm & humid conditions) that dominated the Phanerozoic climate history is associated with continental dispersal, higher sea-floor production, high sea-level and CO2 production. Dispersal and assembly of landmasses that open and close vital oceanic gateways profoundly affect ocean circulations, climate and distribution of fauna and flora. The oceanic ‘carbon source-sink’ processes also depend fundamentally on the configuration of oceanic areas through time: seafloor spreading rate, the length of active ridges, oceanic crust ages, subduction rates, age and latitude of subducted slabs, and the volumes of ocean basins. In addition, subduction processes contribute to changes in global geochemical cycles through sediment recycling and related volcanism.
Aim of theme 2: Dynamic Earth
The Centre for Earth Evolution and Dynamics – CEED, will explore aspects of Earth’s lithosphere dynamics through the 'Wilson Cycles' with a focus on:
- The link between supercontinents, climate and life evolution
- The link between deep mantle plumes, lithospheric heterogeneities and continental break-up
- The link between Wilson cycles, True Polar Wander and long-term climate trends
- The connection between slab subduction, collision and palaeo-topography.
Results from these studies will be used in themes 1 and 3 – DEEP EARTH, and EARTH CRISIS including collaborative ventures (e.g. global climate modelling) with international collaborators.
Sub-themes:
2.1: Supercontinents, Palaeogeography and Biogeography
2.2: Wilson Kickoff: Passive Margins and Break-up
2.3: Continents adrift and oceanic basin formation, true polar wander & climate changes
2.4: Terminal Wilson: Subduction and Collision
