Axis 2

Lithospheric Dynamics

The deformation of rocks, traditionally addressed from a mechanical and physical perspective (e.g., stress, friction), is strongly influenced by chemical processes (fluid-rock interactions, mineralogical reactions, and material transfer) that play a fundamental role in crustal and lithospheric dynamics. In this axis, GEODE group aims to quantify and model the key parameters and processes controlling fluid-rock interactions from the nanometer to centimeter scale.
© Alban Cheviet
Mineralogical and mechanical transformations of Rocks, feedback relationships with fluids

The objectives are to characterize and quantify the mineralogical and petrophysical changes in rocks during interactions with fluids in diagenetic, metamorphic, or hydrothermal systems. The main projects involve (1) changes in the petrological and petrophysical properties of reservoir rocks and sediments during diagenesis, (2) the instability of faults and the triggering of earthquakes, (3) the impact of metamorphic (sub- and suprasolidus) and metasomatic reactions on rock mechanics and the nucleation and operation of shear zones, regardless of pressure and temperature conditions, and (4) the dynamics of gravitational instabilities, particularly through the management of observatories (e.g., Séchilienne [OMIV]).

Lithospheric tectonic processes and related transfers
The interactions between fluids and rocks, along with their mechanical and chemical impacts, are addressed here on a larger spatial and temporal scale. We aim to understand the feedback relationships between deformation partitioning in the crust, fluid circulation, metamorphic and magmatic processes, and their implications for the tectonic and seismo-mechanical evolution of continents.
The primary questions under consideration include: (1) The influence of regional structural inheritance on recent deformation and the nucleation and propagation of seismic events (Jura, Alps). (2) Local earthquakes and microseismic events, and their interactions with subsurface water reservoirs, especially karst (Jura), (3) The role of hydration and dehydration reactions on the control of strain distribution and the trigger of earthquakes, within orogenic crust and along subduction zones, (4) The partitioning of ductile deformation in subduction zones (e.g., the Alps) and in hot, partially molten orogenic crusts (e.g., the Variscan Orogeny, Trans-Hudsonian Orogeny, and Trans-North-China Orogeny).
The research group collaborates with OSU THETA in providing active deformation observation services at the front of the Jura region, including projects such as JURAQUAKE and GPS-JURA [Résif-RENAG].

 © Philippe Goncalves