The recent development of U/Pb LA-ICP-MS analyses on carbonates opened the way to unambiguously constrain the timing of deformation in the brittle field using crystallization of syn-tectonic calcites from fault planes/rocks whatever their size or finite displacement. It appears therefore possible to date increments of slip on a fault plane, to estimate duration of fault activity or the field stress responsible of deformation and ultimately to propose rates of deformation.

In order to explore the deformation record associated with rifting tectonics, a wealky deformed portion of the Golfe du Lion passive margin was selected. Providing exceptional outcrop conditions, the Corbières area displays the most proximal meso-scale normal faults associated with a dense microstructure array.

In a first step, meso-scale structures that are often characterized by thick breccia bodies, were mapped, while their local kinematics were determined. In parallel, microstructures were used to derive robust palaeostress field reconstructions. Results show a quite homogeneous paleostress field in which meso-scale structure integrate well despite a potentially strong tectonic inheritance and a subsequent reactivation. This detailed structural analysis was used as the base for the calcite sampling strategy allowing to select calcite samples from both microstructures and meso-scale fault breccias. Textures, growth history and an evaluation of the geochronological potential of the sample were conducted using conbined catholuminescence and LA-ICP-MS mapping tools on polished 2mm-thick oriented rock-sections.

Geochronological results show a quite large and common age span from ca. 28 Ma to 14 Ma, a dominant between ca. 28 to 21 Ma and a subbordinate between 17 to 14 Ma for both meso-scale structures and microstructures in distinct two age clusters. Taking into account errors, it seems that extensional field stress appears immediately recorded by the activity of meso-scale structures. Proximal portions of the margin far away from the hinge line do record the whole thinning history of the continental crust. The whole volume of the extended domain therefore remained active with dratically different bulk strain rates and fault slip rates. Conversely, it appears tempting to ascribe the ca. 21 to 17Ma period of inactivity to the spreading period in the Algero-Provençal Basin.