Episodic reactivation of carbonate fault zones with implications for permeability – An example from Provence, Southeast France

Early onset of Pyrenean collision (97–90 Ma) evidenced by U–Pb dating on calcite (Provence, SE France)

“…Early stages of subduction of Neotethys Ocean are constrained by shear zone activity at 97-80 Ma in the Eo-alpine orogenic wedge (e.g.,Montemagni et al, 2023), eclogite facies metamorphism in the Sesia-Lanzo zone dated at ca.85-65 Ma (e.g., Cenki-Tok et al, 2011;Inger et al, 1996;Rubatto et al, 1999). Consequently, the tectonic event recorded by the activation of N-directed thrusts and transpressional deformation at 97-90 Ma on East, West and South(Corrêa et al, 2022) parts of Provence region agree with the older range of ages attributed to Africa-Eurasia convergence. Revised stratigraphy of Iberia highlights a similar ~90 Ma compressional phase, featured by long wavelength folds during the Coniacian (Andrieu et al, 2021) at a similar time as shear zone development in the Eastern Alps (97-80 Ma; Montemagni et al, 2023) and as…”

“…In this sample, calcite fibres are observed testifying of a crystallization rate higher than the fracture opening rate and interpreted as the limit between crack‐seal‐slip and crack‐seal textures by Roberts and Holdsworth (2022). This petrological observation suggests that cementation occurred soon after fracturing, included in the uncertainty of the U–Pb age (e.g., Bilau et al, 2023; Corrêa et al, 2022). The dated calcite corresponds to a late stage of the vein opening (Figure 5c) still compatible with the main fibres orientation.…”

“…Based on AFT and stratigraphic cross‐cutting relationships, the uplift of the Massif Central on the western side of the Cevennes Fault is attributed to the Albian‐Aptian (Barbarand et al, 2001; Pagel et al, 1997; Peyaud et al, 2005). Recent studies on the eastern (Provence) side of the Cevennes Fault present younger ages (ranging between 97 and 90 Ma) based on U–Pb geochronology on calcite (Corrêa et al, 2022; Godeau et al, 2018). However, the tectonic context in which the Durance uplift occurred is still puzzling as most authors link this uplift to thermal doming during the development of rifting, like in the Pyrenean domain (e.g., Chorowlcz and Mekarnia, 1992; Balansa et al, 2022), while this event is also recognized as a compressional phase featured by the development of E‐W folds throughout the Provence region (e.g., Caby, 1973; Guieu & Roussel, 1990).…”

“…PFT, penninic frontal thrust; VFZ, ventoux-lure fault. The Star indicates where U-Pb on calcite dating was applied to limestone porosity byGodeau et al (2018) and to calcite cementation related to Castellas fault activity(Corrêa et al, 2022). [Colour figure can be viewed at wileyonlinelibrary.…”

“…[Colour figure can be viewed at wileyonlinelibrary. com] by U-Pb on calcite(Godeau et al, 2018) Domain of Durance Mid Cretaceous emersion (Isthmus) and bauxite formation(Combes 1990) Mesozoic sedimentary cover Dated Castellas fault by U-Pb on calcite(Corrêa et al, 2022) Pyrenean (> 34 Ma) motion…”