Dr Afifé EL KORH
Research domains: Metamorphic petrology, geochemistry
Subduction-related metamorphism, trace element geochemistry, stable isotope geochemistry
Department of Mineralogy
Section of Earth and Environmental Sciences
Rue des Maraîchers, 13
CH-1205 Geneva, Switzerland
Telephone: +41 22 379 66 26
"Geochemical fingerprints of devolatilisation reactions in the high-pressure rocks of Ile de Groix, France". Terre et Environnement 99, 361 pp. (ISBN 2-940153-98-1)
Supervision: PD Dr. Susanne Th. Schmidt and Prof. Urs Schaltegger, in collaboration with Prof. Torsten Vennemann (University of Lausanne).
Collaboration with Dr. Alexey Ulianov (University of Lausanne) and Prof. Michel Ballèvre (University of Rennes, responsible for the Natural Reserve of the Ile de Groix)
Trace element geochemistry and fluid-rock interactions in HP-LT rocks during subduction-related metamorphism (Ile de Groix, Brittany, France)
My research interests concern the petrology and geochemistry of HP-LT metamorphic rocks (metabasites and metapelites of eclogite, blueschist and greenschist facies) representing ancient subduction zones. Subduction zones play an important role in arc magmatism and volatile recycling processes between the oceanic crust, sediments, and mantle lithosphere. According to physical, petrologic and thermal models for the evolution of subduction zones, large quantities of fluids are involved and may be released during the various stages of subduction. My studies focus on the geochemical processes that occurred in ancient subduction zones (example of the Ile de Groix, France), placing a particular emphasis on trace element cycling and fluid-rock interactions.
Five main directions of research are evidenced:
- 1) Trace and rare-earth element exchange behaviours between minerals during the subduction-related HP-LT metamorphism. Characterisation of the geochemical fingerprints that devolatilisation and rehydration reactions have imprinted on the oceanic subducting crust and metasedimentary rocks.
- 2) Fluid-rock and rock-rock interactions at the different stages of the formation of an accretionary complex. Evaluation of the closure state of the systems, based on the whole rock geochemical (major and trace elements) and isotopic (oxygen) composition.
- 3) Study of the HP and retrograde veins as important places for the fluid infiltration and transport. Determination of element transfer processes between the veins and their host rocks during vein formation. Analysis of the geochemical (trace elements) and isotopic (oxygen) composition of the vein minerals, as a result of the fluid composition. Characterisation of the fluid transport mechanisms and sources in subduction zones during prograde and retrograde metamorphism.
- 4) Laser ablation ICPMS U–Pb dating of the protolith of orthogneisses (zircon and titanite) and determination of the metamorphic age in micaschists (titanite). Geodynamical history of the Ile de Groix.
- 5) Thermodynamics of HP-LT metamorphic rocks.
Methods: LA-ICPMS, EMPA, Oxygen stable isotopes, Optical microscopy, SEM.