Fast switch from extensional exhumation to thrusting of the Ronda Peridotites (South Spain)

Gianluca Frasca (1, 2) , Frédéric Gueydan (1) , Marc Poujol (2) , Fleurice Parat (1) , Patrick Monie (1) , Alexandre Pichat (1) , Sophie Mazier (2) , Jean-Pierre Brun (2)

1 Géosciences Montpellier
2 GR - Géosciences Rennes

The Alboran Domain, situated at the western end of the Mediterranean subductionsystem, is characterized by the Ronda Peridotites, one of the world largest exposures of subcontinental mantle. Using U-Pb (LA-ICP-MS) and Ar-Ar dating, we precisely dated twotectonic events associated with the Tertiary exhumation of the Ronda Peridotites. First,shearing along the Crust-Mantle Extensional Shear Zone caused, at ca. 22.5 Ma, mantleexhumation, local partial melting in the deep crust and coeval cooling in the upper crust.Second, the Ronda Peridotites Thrust triggered the final crustal emplacement of theperidotites onto the continental crust at ca. 21 Ma, as testified by granitic intrusions in thethrust hanging-wall. The tectonic evolution of the western Alboran Domain is thereforecharacterized by a fast switch from a continental lithosphere extension in a backarc setting,with sub-continental mantle exhumation, to a rift inversion by thrusting driven by shorteningof the subduction upper plate

Domaines: Tectonique; Géochimie

Gianluca Frasca, Frédéric Gueydan, Marc Poujol, Fleurice Parat, Patrick Monie, et al.. Fast switch from extensional exhumation to thrusting of the Ronda Peridotites (South Spain). Terra Nova, 2017, 29 (2), pp.117-126. ⟨10.1111/ter.12255⟩. ⟨insu-01441962⟩