Lithospheric characterization of the Central Pyrenees based on new magnetotelluric data

Terra Nova, 23, 213–219, 2011 Abstract The Pyrenees resulted from the continent–continent collision between the Iberian and European plates during the Alpine orogeny. Although the subduction of the Iberian lower crust is currently accepted, the physical processes that occur at the boundary between the plates are still a topic of open discussion today, as illustrated by the debate about the presence or absence of partial melting in the Iberian Subducted Lower Crust. Long Period Magnetotelluric data acquired for the first time in the Central Pyrenees constrain the low electrical resistivity structure in the Iberian Subducted Lower Crust better than previous studies, plotting their upper limit 9 km deeper. This new upper limit reinforces the hypothesis of partial melting. Additionally, Long Period Magnetotelluric data constrain the lithosphere–asthenosphere boundary at 90 and 130 km deep below the Iberian and European plates, respectively, and are compatible with electrical resistivity values between 10 and 18 ohm·m for the asthenosphere.