Plymouth University ( Drake Circus Plymouth Devon PL4 8AA United Kingdom - United Kingdom)
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 : Variscan shear zones in the Armorican Massif represent sites of strong fluid‐rock interaction. The hydrogen isotope composition of muscovite (δDMs) from syntectonic leucogranite allows to determine the source of fluids that infiltrated the footwall of three detachment zones and the South Armorican Shear Zone. Using temperatures of hydrogen isotope exchange estimated from microstructural data, we calculate the hydrogen isotope ratios of water (δDwater) present within the shear zones during high‐temperature deformation. A ~40‰ difference in δDwater values from deep to shallow crustal level reveals a mixing relationship between deep crustal fluids with higher δD values that range from −34 to −33‰, and meteoric fluids with δD values as low as −74‰ in the upper part of detachment footwalls.
https://hal-insu.archives-ouvertes.fr/insu-02270566 Contributor : Isabelle DubigeonConnect in order to contact the contributor Submitted on : Friday, August 7, 2020 - 2:19:14 PM Last modification on : Thursday, June 2, 2022 - 2:48:16 PM Long-term archiving on: : Monday, November 30, 2020 - 4:22:43 PM