Subduction Initiation reconstructed from Neotethyan Kinematics (SINK): An integrated geological and numerical study of the driving forces behind plate tectonics
05 / 2012 - onbekend
The concept of Plate Tectonics, as fundamentally unifying to Earth Sciences as Darwin?s Evolution Theory is to Life Sciences, provides a mathematical description for the complex evolution of Earth?s outer shell in terms of lithosphere plates and their interactions. There is no generally accepted dynamic mechanism, however, that explains why plate tectonics developed and continues. A key element of plate tectonic is subduction of oceanic lithosphere back into the mantle, compensated by spreading of new oceanic lithosphere elsewhere. Half of the subduction zones active today formed since ~60 million years, and subduction initiation must be a common and fundamental element of plate tectonics. Geophysical models demonstrate that tractions acting on pre-existing weakness zones are required to initiate subduction. Potential mechanisms to produce this forcing remain unexplored, but may include clogging of existing subduction zones with continental lithosphere, formation of high plateaus as a result of absolute plate motions and arrival of mantle plumes below plates. I aim to identify the mechanisms producing the forcing of subduction initiation, using a novel and multidisciplinary approach. (1) I will design a geological Natural Laboratory, in which subduction initiation events, absolute and relative plate motions, continental collisions and mantle plumes are reconstructed. The Alpine-Himalayan mountain range, which formed during closure of the Neotethyan Ocean, is an ideal natural laboratory, in which subduction initiation events, and geological expressions of all potential driving mechanisms have been and will be reconstructed. (2) To test whether the reconstructed geological ?incidents? are causally related, numerical modeling experiments will be conducted based on fundamental physical principles. The SINK project will use an iterative integration of natural laboratory study and numerical experiments to advance our understanding of the processes that drive subduction initiation, as an essential step towards a dynamic and quantitative model to explain plate tectonics.