4D-UTECTONICS · Four dimensional microtectonics: quantifying complex deformation paths through time in natural shear zones deformed by general shear
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2006-04-01 → 2008-03-31
- EU contribution
- €188,558
- Participants
- 1
- Scheme
- EIF
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Results in brief
Final Activity Report Summary - 4D-UTECTONICS (Four dimensional microtectonics: quantifying complex deformation paths through time in natural shear zones deformed by general shear)
Movement of the Earth's plates is typically accommodated in zones of localised deformation, and movement along these faults is the main cause of earthquakes. 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. Recent work has shown that the tools used for studying shear zones are inadequate in a very common, complex type of shear zone deformation (transpression). In this study, we have tested a new micro-kinematic approach that helps to track the three-dimensional evolution of faults and shear zones through time (i.e. 4D micro-tectonics). This was done on rock samples from Cap de Creus, Spain, using the orientation of quartz grains, which change their shape and orientation during this deformation in a very specific way. The orientation was obtained using the electron backscatter diffraction technique (EBSD) on a scanning electron microscope (SEM). The results confirm that we have an independent means of establishing the kinematic rotation axis (vorticity vector) of rock samples. This means we can now better test theoretical models of how rocks deform in the middle crust (in general shear). This also aids us in understanding the evolution of mountain belts in general, and fault behaviour in particular.
Data: CORDIS, © European Union
Project objective
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.
Original text from CORDIS.
Participants
- UNIVERSITAET BERN · BERNCoordinatorSwitzerland
Links
Data: CORDIS, © European Union