Rheology Studies
Orogeny leads to crustal thickening, followed by thermal relaxation and radiogenic production in the thickened crust, culminating in crustal melting and magma intrusions which significantly decrease the crustal viscosity and ultimately cause post-orogenic collapse. During the extension that accompanies orogenic collapse, the upper crust thins by brittle faulting, while the lower crust flows laterally. Localization of the deformation in the upper crust eventually leads to the formation of a metamorphic core complex. In a MCC, a ten to hundred meters thick detachment shear zone (DSZ) separates the brittlely deformed hanging wall from the footwall. DSZs commonly record the transition from brittle to ductile deformation, and are associated with high metamorphic gradients. MCCs and their associated DSZs are therefore ideal setting to study the rheology of the crust.
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This project aims at constraining the timing, strain, strain rate, stress, vorticity, and kinematics of during the evolution of the DSZ in order to better understand crustal processes. This involves doing fieldwork, structural and microstructural analysis, various strain analysis, geochemistry (argon, oxygen and hydrogen stable isotopes, mineral chemistry).