Movement along faults is a direct response to deformation of the Earth's strong outer shell (the lithosphere), and the main cause of earthquakes. The displacement of lithospheric plates across the Earth's surface is typically accommodated within localized deformation zones such as brittle faults or ductile shear zones. If we are to predict when faults move and by how much, we need to understand the fundamental processes that govern this deformation. As displacement in brittle faults near the earth's surface is linked to ductile flow in shear zones at depth, it is critical to understand the evolution of ductile, deep-crustal shear zones in both space and time. Yet, the mechanisms behind partitioning of deformation into structures that accommodate different types of displacement are not well understood, and recent work has shown that tools and concepts used for studying shear zones are inadequate in a very common, complex type of shear zone deformation (transpression). What is needed now is a new micro-kinematic approach that will make it possible to track the three-dimensional evolution of faults and shear zones through time (i.e. 4D micro-tectonics).
This process-based study aims to constrain the 4D kinematic history of transpressional shear zones by a multi-disciplinary approach, integrating a variety of geological analytical techniques with a novel method employed in materials science (Electron BackScatter Diffraction or EBSD). The outcome will be a well-constrained, field-based model for evolution of crustal-scale transpressional shear zones and the development of a novel integrated, quantitative methodology for micro-kinematic analysis of deformation. The proposed fellow will gain hands-on expertise in state-of-the-art analytical techniques, and the project may act as a catalyst for collaboration between the host institution in Switzerland (an Associated State) and other institutions in Europe as well as in Australia.
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