New paleomagnetic Mesozoic data from the Algarve (Portugal): fast rotation of Iberia between the Hauterivian and the Aptian

We sampled nine sites of Jurassic and Cretaceous limestones in the Algarve region, Portugal. Our study yields a paleopole for the Portlandian-Valanginian (Φ = 256°, λ = 58°, A95 = 5°) and a paleopole for the Aptian-Albian (Φ = 232°, λ = 75°, A95 = 8°). These results allow better constraint of the relative rotation of Iberia with respect to Europe: this rotation of 22° ± 14° is a rather fast event occurring during the Barremian, between 132 and 124 Ma. Confinement of Iberia between Africa and Eurasia would explain the rapid rotation of this microplate. The Iberian plate was probably attached to Europe until 132 Ma, then detached from Europe and acted as an independent plate during the time of fast rotation preceding the oceanic spreading in the Bay of Biscay.