Reply to comment by P. Olivier on “Thermal control on the modes of crustal thinning leading to mantle exhumation: Insight from the Cretaceous Pyrenean hot paleomargins”

Camille Clerc (1) , Yves Lagabrielle (2)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 GR - Géosciences Rennes

We thank Philippe Olivier for the great attention he paid in reading our work and for the discussion he initiated. P. Olivier has been alarmed by our proposition that some Pyrenean granulites might have been (re)granulitized during the Cretaceous rifting event. In a rigorous scientific approach, this hypothesis has to be envisioned. However, in the paper, we proposed two alternative scenarios: one involving a Cretaceous (re)granulitization and another one implying a succession of metamorphic events with a first Paleozoic High Temperature (HT) metamorphism event responsible for the granulitization, followed by a second HT metamorphism event during the Cretaceous. Our main point here was to put in relation the strikingly similar fields of metamorphisms responsible for the granulitization of the crystalline basement and for the HT metamorphism of the prerift and synrift Mesozoic sedimentary cover. In other words: with temperatures up to 600°C in the metasedimentary cover, we would expect temperatures at least as high as 600°C in the basement. If not, it would mean that the continental crustal basement was already withdrawn from the metamorphic domain at that point. This scenario corresponds in fact to the concept of lateral extraction of the continental crust that we retained from our field constraints and that we defend here.

Domains: Tectonics

Camille Clerc, Yves Lagabrielle. Reply to comment by P. Olivier on “Thermal control on the modes of crustal thinning leading to mantle exhumation: Insight from the Cretaceous Pyrenean hot paleomargins”. Tectonics, 2015, 34 (10), pp.2275-2278. ⟨10.1002/2015TC003879⟩. ⟨insu-01220281⟩