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Timing of Eocene–Miocene thrust activity in the Western Axial Zone and Chaînons Béarnais (west-central Pyrenees) revealed by multi-method thermochronology
2GR - Géosciences Rennes (Bâtiment 15 - Université de Rennes 1 - Campus de Beaulieu -263 Av du général Leclerc- CS 74205 - 35042 Rennes Cedex - France - France)
Abstract : We present new apatite (U–Th)/He (AHe), apatite fission track (AFT) and zircon (U–Th)/He (ZHe) data to unravel the timing of exhumation and thrusting in the western Axial Zone of the Pyrenees and the adjacent North Pyrenean Zone (Chaînons Béarnais). In the north, ZHe data yield cooling signals between 26 and 50 Ma in the Chaînons Béarnais, which are consistent with the onset of thrust-related cooling in the neighboring Mauléon Basin modeled by previous authors. Non-reset Triassic ages are found in the footwall of the North Pyrenean Frontal thrust (Aquitaine Basin). To the south, similar ZHe ages in both the hanging wall and footwall of the Lakora thrust record Late Eocene to Oligocene cooling that we attribute to the activity of the Gavarnie thrust. Thermal modeling of samples from the Lakora thrust hanging wall indicates cooling from Early Eocene times, recording activity of the Lakora thrust. Paleozoic detrital samples from the westernmost Axial Zone and from the Eaux-Chaudes and Balaitous–Panticosa granitic plutons yield AFT signals between 20 and 30 Ma and ZHe between 20 and 25 Ma. Modelling indicates fast cooling during this time, which we attribute to the motion of the Guarga thrust. AHe data from these Axial Zone plutons, combined with modelling, show a post-tectonic signal (8–9 Ma), which indicates renewed erosion after a period without major cooling and exhumation between 20 to 10 Ma.
https://hal-insu.archives-ouvertes.fr/insu-01301995 Contributor : Isabelle DubigeonConnect in order to contact the contributor Submitted on : Tuesday, March 2, 2021 - 5:13:28 PM Last modification on : Tuesday, July 5, 2022 - 10:02:31 AM Long-term archiving on: : Monday, May 31, 2021 - 7:39:02 PM
Gemma de Vicente I Bosch, Antonio Teixell, Marc Jolivet, Pierre Labaume, Daniel Stockli, et al.. Timing of Eocene–Miocene thrust activity in the Western Axial Zone and Chaînons Béarnais (west-central Pyrenees) revealed by multi-method thermochronology. Comptes Rendus Géoscience, Elsevier, 2016, From rifting to mountain building: the Pyrenean Belt, 348 (3-4), pp.246-256. ⟨10.1016/j.crte.2016.01.001⟩. ⟨insu-01301995⟩