Soto, R., J. C. Larrasoaña, E. Beamud, and M. Garcés (2016), Early-Middle Miocene subtle compressional deformation in the Ebro foreland basin (northern Spain); insights from magnetic fabrics, Comptes Rendus – Geoscience, 348(3-4), 213-223, doi: 10.1016/j.crte.2015.10.009.
Abstract
The results of anisotropy of magnetic susceptibility analyses of 19 sites carried out on magnetostrigraphically-dated, Lower to Middle Miocene (20.4 to 13.7 Ma) “non-deformed” mudstones from the central part of the Ebro basin reveal the presence of a subtle tectonic overprint lasting at least until the Langhian (Middle Miocene) in the southern Pyrenean foreland. Magnetic ellipsoids show a sedimentary fabric in 42% of sites and a weak and well-defined magnetic lineation in 47% and 11% of sites. The magnetic lineation is roughly oriented around the east–west direction, compatible with a very weak deformation occurring there and related to the north–south compression linked to the convergence between Europe, Iberia and Africa during the Early–Middle Miocene. A slight variation of the magnetic parameters Km, Pj, and T exists through time, probably due to changes in the sedimentary conditions in the basin.