Project

mantle wedge; subduction; mantle convection; shear zone; plate tectonics; supercontinent

Lead
Lay summary
The development of the theory of plate tectonics in the 1960s has shaped our knowledge and understanding of the Earth for more than four decades. Even so, many questions still remain unsolved due to the complexity of the plate-mantle system. One major unknown is the link between large-scale global characteristics like the distribution of tectonic plates and their interaction with the floating continents, and smaller-scale processes that cause localization of deformation and heterogeneity at all scales in the lithosphere. The research project presented here will investigate processes from global and regional scales in an attempt to answer the following key questions: (i) What is the role of pre-existing lithospheric heterogeneity on the evolution of plate tectonics? (ii) What are the governing processes to generate lithosphere-scale shear zones and how is subduction initiated? (iii) How do fluids and rocks interact in subduction settings and influence the evolution of subduction zones? All of these questions will be addressed using state-of-the-art numerical models of geodynamical processes, and various other disciplines of Earth sciences will give important constraints and help to push our understanding of these processes forward. The requested funding is to extend for one year the funding of three existing PhD students who were previously funded from the EU Marie-Curie network Crystal2Plate.

Direct link to Lay Summary

Last update: 21.02.2013

Active participation

Number	Title	Start	Funding scheme

The development of the theory of plate tectonics in the 1960s has shaped our knowledge and understanding of the Earth for more than four decades. It was one of the major advances in Earth sciences as it provides a basic framework for the processes that can be observed at Earth's surface, and also for those relevant in the deep interior of the planet and the link between the two. The principles of plate tectonics allow for a general understanding of long-term processes like plate boundary formation, continent-ocean interaction and mountain building, but also short-term, more catastrophic events like earthquakes and magmatic activity, for instance volcanic eruptions.In its original form, plate tectonics was not linked to deep Earth processes evoked by the large-scale convection of the mantle, with the result that both mechanisms were treated almost independently. However, over the last 15 years extensive research on both systems using many different techniques has led to an improved understanding of plate tectonics that is now widely accepted: mantle convection and plate tectonics are not independent processes, but are different aspects of the same process, with the tectonic plates being the surface expression of the Earth's mantle convection.Many questions, for example, regarding the driving forces of plate tectonics, have become much clearer since then, but many others still remain unsolved due to the complexity of the plate-mantle system. One major unknown in our understanding is the link between large-scale global characteristics like the distribution of tectonic plates and their interaction with the floating continents, and smaller-scale processes that cause localization of deformation and heterogeneity at all scales in the lithosphere.The research project presented here will investigate processes from global and regional scales in an attempt to answer the following key questions:(i) What is the role of pre-existing lithospheric heterogeneity on the evolution of plate tectonics?(ii) What are the governing processes to generate lithosphere-scale shear zones and how is subduction initiated?(iii) How do fluids and rocks interact in subduction settings and influence the evolution of subduction zones?All of these questions will be addressed using state-of-the-art numerical models of geodynamical processes, and various other disciplines of Earth sciences will give important constraints and help to push our understanding of these processes forward. In particular these are: geology, petrology, geochemistry, mineral physics and fluid mechanics. The international research team working on these questions consists of three senior researchers with long experience in geodynamics, numerical modeling and geology and three PhD students. The PhD students have already been funded for 3 years as part of a European Marie-Curie network (CRYSTAL2PLATE, grant agreement number: PITN-GA-2008-215353), have already made much progress related to the stated questions (including some publications) and are integrated into an interdisciplinary network. The 12-month extension requested here from SNF would allow the three student to capitalize on the advances and time investment they have already made by pushing the research much further, which would provide substantial added value and make them better prepared for the next stage of their careers. Three experienced PhD students could, in one year, accomplish much more than a single, beginning PhD student working for three years.