Key to understanding the complex Mediterranean subduction history is the kinematic reconstruction of its paleogeography after Jurassic extension between Iberia, Eurasia, and Africa. While post-Eocene Liguro-Provençal back-arc extension, and associated Miocene ~50° counterclockwise (ccw) rotation of Sardinia-Corsica have been well documented, pre-Oligocene reconstructions suffer uncertainties related to the position of Sardinia-Corsica with respect to Iberia. If a previously constrained major post-middle Jurassic, pre-Oligocene rotation of Sardinia-Corsica can be quantified in time, we can test the hypothesis that Sardinia-Corsica was (or was not) part of Iberia, which underwent a ~35°ccw during the Aptian (121-112 Ma). Here, we present new paleomagnetic results from Triassic, Jurassic, Upper Cretaceous and Lower Eocene carbonate rocks from Sardinia. Our results show a consistent post-early Eocene ~95°ccw rotation relative to Eurasia. An Eocene ~45° ccw rotation of Sardinia-Corsica thus postdated the Iberian rotation. This implies that the two domains must have been separated by a (transform) plate boundary. The Eocene rotation of Sardinia-Corsica was synchronous with and likely responsible for documented N-S shortening in the Provence and the incorporation of the Briançonnais continental domain, likely connected to Corsica, into the western Alps. We argue that this rotation resulted from the interplay between a southward 'Alpine' subduction zone at Corsica, retreating northward, and a northward subduction zone below Sardinia, remaining relatively stationary versus Eurasia.
|Titolo:||Eocene rotation of Sardinia, and the paleogeography of the western Mediterranean region|
|Data di pubblicazione:||2014|
|Tipologia:||1.1 Articolo in rivista|