Experimental-numerical constraints on the rheological impact of metamorphic reactions

PhD position in experimental constraints on rheology during metamorphic reactions

Main host institution: Ecole Normale Supérieure de Paris, France

Secondement Institutions: ISTerre Grenoble, Frei Universität Berlin (FUB)

The Laboratoire de Géologie of ENS PARIS seeks to appoint a PhD student in experimental rheology. The successful applicant will join the Rock Mechanics team in Paris and will work in a multi—disciplinary environment in close collaboration with Dr. Alexandre Schubnel in Paris, Dr. Stéphane Guillot in Grenoble and Dr. Timm John in Berlin.

In the last twenty years, transformation–‐induced faulting has been evidenced in several rocks undergoing phase transformations both in the laboratory and in the field. Observations have led to believe that phase transformations must play a major role in the triggering and the propagation of earthquakes in subduction environments. Nevertheless, the way mineral reactions can modify the deformation regime of deep rocks, from ductile to brittle  (embrittlement) remains poorly understood, mainly because of the technological challenge it represents. Indeed, being able to deform rocks in a controlled manner at HP- ‐HT conditions, while contemporaneously monitoring the reaction progress, proves to be a challenging interdisciplinary task that lies at the frontier between the High Pressure and the Rock Mechanics communities.

On a practical point of view, systematic set of experiments will be performed in order to characterize the mechanics of a number  of phase transitions (Serpentine dehydration and Eclogitization reactions) typical of subduction zones. Experiments will be performed in a newly designed solid medium deformation (Griggs type) apparatus equipped with acoustics, which will be installed at ENS Paris early 2014. Additional experiments will be performed in the multi–‐anvil deformation apparatus (D–‐DIA) now fully operational on the GSECARS beam line of the Advanced Photon Source synchrotron in Argonne Illinois, USA.

It is crucial for experimentalists to be forced into thinking at a larger scale. In consequence, this project also involves two field studies (Voltri, Italy; Western Gneiss Region, Norway) in order to remember what kind of microstructures we are to reproduce in the laboratory.

Methods: High pressure experiments, some under synchrotron radiation; High frequency acoustics; Petrology; Microscopy (SEM, EBSD, TEM); Field work; mechanical modeling.

Candidates must hold an MSc in Earth Sciences, Applied Mathematics, Physics or a related discipline. Experience and interest in both experimental science -­ in particular high pressure experiments-­ and field geology is highly advantageous. During his PhD, the candidate is expected to collaborate with scientists from various horizons and spend time in the secondment institutions (Grenoble and Berlin), and learn a number of state-­of-­the-­art experimental and analytical techniques.

ENS Paris is situated in the heart of the Latin quarter. Paris is a world capital and yet an extremely liveable city, being one of the largest cultural center in Europe. For further information, please contact Alexandre Schubnel (aschubnel@geologie.ens.fr), Stéphane Guillot (Stephane.Guillot@ujf-grenoble.fr) or Timm John (timm.john@fu-°©‐berlin.de)

Starting date is expected between January and May 2014.

New deadline to apply: Nov, 13th 2013.