ERC Advanced Grant 'Beyond Plate Tectonics'

The plate tectonic theory gave us the framework to understand the deformation and volcanism at plate boundaries. It allowed us to understand surface plate motions, but did not include a mechanism to explain the dynamics of the underlying convective system caused by heat escaping from the core and mantle, and origin of intra-plate volcanism such as hotspots and Large Igneous Provinces (LIPs). Beyond Plate Tectonics explores the mechanisms linking surface volcanism and deformation with processes in the mantle. A main hypothesis is that mantle plumes from the edges of stable areas with low seismic shear velocity above the core-mantle boundary can explain the surface distribution of most hotspots, LIPs and kimberlites.

European Research Council

About the project

Plate tectonics, as fundamentally unifying to the Earth Sciences as Darwin's Evolution Theory is to Life Sciences, characterises the complex and dynamic evolution of the outer shell of the Earth in terms of rigid plates. These plates overlie and interact with the Earth's slowly convecting mantle.

Even though our understanding of links between mantle convection and plate tectonics is improving, notably through subsurface tomographic images, advances in mineral physics and improved absolute plate motion reference frames, there is still no generally accepted mechanism that consistently explains plate tectonics in the framework of mantle convection. It is now a prime challenge to integrate Plate Tectonics into Mantle Dynamics.

Objectives

Our prime aim is to integrate plate tectonics into Mantle Dynamics and develop a theory that explains plate motions quantitatively and dynamically. We will develop a new model of plate kinematics that will be linked to the mantle with the aid of a new plate motion reference frame based on moving hotspots and on palaeomagnetic data. A global reference frame will be corrected for true polar wander (rotation of the entire Earth relative to its spin axis) in order to develop a reference frame with respect to the mantle. The resulting plate reconstructions will constitute the input to subduction models that are meant to test the consistency between the reference frame and subduction histories.

The final outcome will be a novel global subduction reference frame that will be used to explore links between surface processes such as eruption of large igneous provinces and heterogeneities in the deepest mantle.

Background

Scientists at the University of Oslo and the Geodynamics Group at the Geological Survey of Norway play active roles in the project, in addition to several international members of the project Team (e.g. GFZ, Potsdam and Utrecht University) who add scientific value to the project.

The project was originally administrated by the Physics of Geological Processes (PGP), one of Norway’s first Centers of Excellence.

Sub-projects

  • Develop quantitative global plate circuits back to Pangea assembly
  • Develop a global mantle frame since the Cretaceous
  • Develop a global apparent polar wander path which includes correction for sedimentary inclination shallowing and potential non-dipole field contributions
  • Devise time-dependent shapes of continents and plate boundaries back to Pangea assembly
  • Construct a new set of global digital palaeo-age grids
  • Develop numerical subduction models which are driven by plate motions
  • Generate reconstructions for all large igneous provinces (LIP) and kimberlite eruptions since Pangea time to test the slab initiation model
  • Categorize & examine all LIPs and kimberlites outside of Pangaea or older than Pangea assembly, for which no longitude control exists

Financing

Advanced Grant (AdG), details: ERC-2010-AdG_20100224.

Project period is from 2011 to 2016.

Cooperation

Published May 6, 2015 3:56 PM - Last modified Oct. 31, 2018 3:19 PM

Contact

Trond Helge Torsvik, Professor