Stable isotopes fractionation during seismic rupture
A large proportion of Earthquake nucleates within carbonate bearing sediments. It has been experimentally demonstrated that seismic rupture ,or reactivation of pre-existing fault, is associated by a partial thermal decomposition of carbonates in CO2. In this project we aim to investigate the thermal decomposition of carbonate from experiments and natural fault analogues using O and C stable isotopes.
Fluid transfer between seismic and aseismic portions
Fluids compose a key compenent of fault. Their presence are well documented by the presence of veins and newly formed clays, which could modify the fault strenght. We are especially intersted in tracking the sources of fluid passing through fault during their activity. Our first priority is to adress the link between seismic and aseismic portions from the same faults.
Application of Clumped isotope
The mass-47 clumped isotope is a novel tools to document the formation temperature of carbonate (sediments, veins) in low temperature without making assumptions about the fluid composition. Therefore we apply this technique to gain knowledge about temperature and fluid conditions during fault activity, and to reconstruct the paleo-elevation of mountains.
Gold deposits emplacement
Many Au-deposit are structurally controlled along faults or shear zones (e.g. orogenic gold system). However Au-mineralization is strongly influenced by the P-T-t conditions of deformation. Our working group is currently working on different orogenic Au-deposits located worlwide (USA, East Africa and Europe) to document their conditions of formation. For this we combine field-based geological and structural mapping to petrological and geochemical tools (stable isotope, fluid inclusions, Raman, U-Pb dating...).
