We are looking for a highly motivated student with a strong interest in deformation processes and/or metamorphic petrology. Experience with one of the analytical techniques mentioned above and/or phyllosilicate-rich rocks will be appreciated. The applicant should hold a Master degree (or equivalent) in Earth Sciences.
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Sujet
Phyllosilicate deformation and its effect on shear zone formation and fluid circulation in the upper and middle crust: an experimental study of the deformation mechanisms of mica-quartz assemblage
Encadrement
Laura Airaghi, Holger Stünitz, Hugues Raimbourg et Jacques Précigout
Résumé
The mechanisms of strain localization within ductile shear zones in the Earth crust strongly control the dynamics of mountain belts, the nucleation of earthquakes and the formation of lithospheric structures. Fluid influxes during deformation play a major role in the development of these shear zones by means of mineralogical transformations such as the growth of phyllosilicates (as micas). The aim of this project is to investigate the role of micas in strain accommodation and development of shear zones within the upper to middle crust, from the scale of crystal defects to the polycrystalline aggregate.
The project will combine detailed microstructural and petrological study of the mica-quartz samples experimentally deformed under different temperature and strain rate conditions with the observation of naturally deformed samples. A major component of the project will be the characterisation of the deformation mechanisms of phyllosilicates (intra-crystalline, polycrystalline, two-phase mineral aggregate), their dependency on chemical composition as well as the role of mineral reactions in strain accommodation. The project will include the use of multiple techniques, such as the new generation Griggs apparatus, SEM and EBSD, microprobe and TEM.
This project is part of the Labex Voltaire, an interdisciplinary research program focused on fluid transfers in the upper envelopes of the solid Earth. The Voltaire program will provide both the salary for the Ph.D. student and the financial support for PhD research activities.
Contacts
Laura Airaghi (laura.airaghi@univ-orleans.fr)
Date limite de candidature
15 Juin 2020