How sensitive are intraplate inherited structures? Insight from the Cevennes Fault System (Languedoc, SE France)

Deformation in intraplate domains is usually considered as a consequence of tectonic events at plate boundaries. Nevertheless, the occurrence of intraplate earthquakes such as the recent Le Teil event in the south of France along the Cevennes Fault System (CFS), on 11 November 2019, Mw = 4.9, questions whether this far-field deformation only occurs during tectonic pulses at plate boundaries, or if it corresponds to low-intensity but regional continuous deformation through time. To address this question, we have coupled U-Pb geochronology of fault-related calcites with structural analysis along a major fault system (the CFS) in the South-East Basin, France. Weevidence (1) an Albian activity of the CFS and (2) a continuous compressional activity of the CFS and satellite structures during the whole Eocene and probably during the Late Cretaceous - Palaeocene, including periods (e.g. Lutetian) usually considered as phases of tectonic quiescence. We thus demonstrate that the tectonic reactivation of this intraplate fault system is not restricted to periods of high rates of deformation at plate boundaries.

Automated summary

Deformation in intraplate domains is not only limited to tectonic events at plate boundaries, but can also occur as low-intensity continuous deformation in far-field regions. The study of the Cevennes Fault System in the South-East Basin, France, using U-Pb geochronology and structural analysis, reveals continuous compressional activity throughout the Eocene and possibly the Late Cretaceous - Palaeocene, challenging the notion of tectonic pulses at plate boundaries as the sole cause of far-field deformation.