118125 20220908140458.0 doi 10.1007/s11200-017-0143-6 sideral 105452 ART-2018-105452 eng Oliva-Urcia, Belén (orcid)0000-0003-1563-6434 New insights into asymmetric folding by means of the anisotropy of magnetic susceptibility, Variscan and Pyrenean folds (SW Pyrenees) 2018 Magnetic fabric allows to unravel the petrofabric of sedimentary rocks and to assess their deformational history. The use of this technique, in addition to classical structural field observations in the limbs of seven asymmetric folds in the Pyrenees, helps to determine the differences of internal deformation as well as the folding kinematics. Three folds developed during the Variscan Orogeny in Ordovician and Devonian rocks, and four folds developed during the Pyrenean Orogeny in Eocene rocks, are studied. Folds show a variety of structural locations, in different thrust sheets of the Southern Central Pyrenees, different cleavage development, age, geometry and lithology. Sampling follows an equivalent lithological layer in the two limbs, except for one case, of the selected folds. Results show a modified tectonic magnetic fabric in most sites with the magnetic lineation on the tectonic foliation plane. A larger scattering of the magnetic lineation (maximum magnetic anisotropy axis) and a higher intensity of the preferred orientation of minerals (eccentricity of the anisotropy of magnetic susceptibility - AMS ellipsoid) is better observed in the overturned (short) limb of the asymmetric Variscan folds than in the normal (long) limb. On the other hand, the shape parameter in Alpine folds is generally larger in the overturned (short) limb respect to the normal (long) one. A good clustering of the minimum magnetic anisotropy axes is observed in all limbs. The combination of the AMS data with the structural data helps to understand and better constrain the deformation degree in these asymmetric folds and to unravel the deformational history. Access copy available to the general public Unrestricted info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 1.293 2018 GEOCHEMISTRY & GEOPHYSICS 59 / 84 = 0.702 2018 Q3 T3 0.532 2018 Geophysics 2018 Q2 Geochemistry and Petrology 2018 Q2 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Gil-Peña, Inma Soto, Ruth (orcid)0000-0002-1929-8850 Samsó, José María Antolín, Borja Pueyo, Emilio L. Universidad de Zaragoza (orcid)0000-0002-0504-2352 2000 428 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Geodinámica Interna 62 (2018), 291-322 Stud. geophys. geod. STUDIA GEOPHYSICA ET GEODAETICA 0039-3169 1827950 http://zaguan.unizar.es/record/118125/files/texto_completo.pdf Postprint 1925231 http://zaguan.unizar.es/record/118125/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:118125 articulos driver 2022-09-08-11:33:02 ARTICLE