Polyphased brittle deformation around a crustal fault: A multi-scale approach based on remote sensing and field data on the mountains surrounding the Têt hydrothermal system (Eastern Pyrénées, France)

Abstract

Highlights1. Geological features of adjacent mountains that allow the hydrothermal circulation.2. The Têt fault system was formed during recent and polyphased tectonic stages.3. Plio-Quaternary brittle faulting is widely distributed and reactivates oldest faults. 4. Fracture opening at depth are favored in crystalline rocks than in metasediments.5. Fault intersections with background fracturing provide pathways for hydrothermal fluids.

Deciphering the Cenozoic Exhumation History of the Eastern Pyrenees Along a Crustal‐Scale Normal Fault Using Low‐Temperature Thermochronology

“…Note that despite the proximity of a huge gouge zone and evidence for fluid alteration, the Rare Earth Element distribution of this sample remains unaffected by hydrothermalism (see Figure S4 in Supporting Information S1) compared to our previous observations along the Têt fault itself (Milesi, Monié, Münch, et al., 2020). NW‐SE trending faults are frequent in this western segment of the Têt fault (see Milesi, 2020; Taillefer et al., 2021) and their activity can account for an important segmentation of the Carança massif with therefore a spatial variability in AHe data due to slightly different cooling histories within the different sub‐blocks. In spite of these local perturbations by NW‐SE faults in the Carança block, AHe and ZHe data are well reproduced by the QTQt model (Figure 6c), and only mean track lengths show important differences between observed and modeled data, which can be explained by the small amount of tracks measured on the three samples (see Table 2 for details).…”

“…In the Carança massif, thermal modeling based on AHe data (Milesi, Monié, Münch, et al., 2020; Milesi et al., 2019) suggests two main cooling events that occurred in the Oligo‐Miocene, a major one between 30 and 24 Ma (at a rate of 25°C/Ma) followed by a second episode between 12 and 9 Ma (at a rate of 15°C/Ma). Despite these previous thermochrological studies, the spatio‐temporal evolution of the main tectonic structures in the eastern part of the Axial Zone of the Pyrenees since the Priabonian remains still poorly constrained (see Taillefer et al., 2021).…”

“…This orogen segment shows a similar nappe structure as further West (Calvet et al., 2021; Laumonier et al., 2015, 2017) but has experienced significant post‐orogenic crustal thinning to 25 km of total thickness, as indicated by recent geophysical data (Chevrot et al., 2018; Diaz et al., 2018; Lacan & Ortuño, 2012; Nercessian et al., 2001). This thinning is assigned to the presence of numerous and widely distributed normal faults onshore and offshore (Calvet et al., 2021; Jolivet, Menant, et al., 2021; Jolivet et al., 2020; Romagny et al., 2020; Séranne et al., 2021; Taillefer et al., 2021). The geodynamic origin for the onset of the extension has been linked to either the initiation of the West European Rifting which formed a large intraplate feature (Angrand & Mouthereau, 2021; Mouthereau et al., 2021) or the early onset of back‐arc extension leading to the formation of the Gulf of Lion (Séranne, 1999; Séranne et al., 2021) The Têt fault is the most prominent normal fault of the Eastern Pyrenees, which localizes high‐relief massifs in its footwall such as the Canigou and Carança (Figure 1).…”

“…The development of these high topographic reliefs has been attributed to normal faulting during the Oligo‐Miocene period (Maurel et al., 2008). However, the pre‐extensional history of this area, the onset of extension and its polyphase activity along strike during the Cenozoic are still poorly understood (e.g., Angrand & Mouthereau, 2021; Huyghe et al., 2020; Jolivet, Baudin, et al., 2021; Jolivet, Menant, et al., 2021; Jolivet et al., 2020; Taillefer et al., 2021).…”

“…The study area is outlined with an open purple‐dashed box. (b) Structural sketch map of the study area showing the different massifs (in bold italics) and basins (in italics) along the Southwestern (SW) and Northeastern (NE) segments of the Têt fault (modified from Taillefer et al., 2021). Secondary faults are indicated by red numbers (see legend for details).…”