Stable Isotope geochemistry
Stable isotope technique composes a suitable tool to constrain the to assess the nature/source of fluid, the fluid-rock interaction processes during fault activities. They are also useful to determine the temperature of deformation processes.
We are principally interested in the calibration of new oxygen fractionation curve between quartz, calcite and chlorite, minerals commonly found along fault zones, associated with ore deposit (gangue) and or related to maturation of organic matter to hydrocarbon.
In addition we also perform mass-47 clumped isotope on carbonate system to understand larger tectonic processes such as paleo-elevation and paleofluid flow associated to major fault zone activity.
Why fault are weak ?
One of the most important aspect of our research is to understand why and how fault become weak. What are the chemical processes involved ? and, What is the kinetic (in terms of fault displacement) of weakening processes ?
For this I use a multiapproach consisting of mass balance calculation and very fine microstructural analyses coupled to a mechanical experiments on a biaxial apparatus (INGV, Roma).
The principal result of this research is that the weak properties of a fault occur during the incipient stage of a fault development (Lacroix et al. 2015 and Tesei et al. 2015).
Thermal evolution of the basin
Constraining the thermal history of tectonically active basins is of special importance. The estimation of geothermal gradients and their evolution thorough time are basic parameters to understand the tectono-sedimentary evolution of fold-and-thrust belts and associated foreland basins. To investigate the thermal evolution we use classical methods, including clay mineralogy, vitrinite reflectance, fluid inclusion microthermonmetry and illite crystallinity coupled to novel tools such as Raman Spectrometry on Carbonaceous Material (RSCM) and mass-47 clumped isotopes.
