[en] The Ibero-Armorican orocline is a central component of the Western European Variscan Belt, a complex continental-scale orogen (1000 km wide and 8000 km long) that formed through a series of protracted collisional events extending from ca.420 Ma to 320 Ma. Variscan deformation represents the closing of at least two ? and possibly four ? oceans between Laurentia, Baltica, Gondwana, and several micro-continents during the Paleozoic amalgamation of the Pangea supercontinent. The Ibero-Armorican orocline is characterized by the arcuate structural trend that traces an arc from Brittany across the Cantabrian Sea into western Iberia, where it is truncated by the Cenozoic Betic-Alpine front in southern Spain. New studies consider the Ibero-Armorican orocline as part of a coupled bend together with the southern Central-Iberian arc. The Ibero-Armorican orocline is a curved orogenic system characterized by a 180o bend of the Variscan structural grain. The Ibero-Armorican orocline has been the object of many studies, especially at its core. The aforementioned studies have attempted to decipher the curved mountain belt kinematics, and a wealth of different hypotheses have been proposed: a primary arc inherited from a Neoproterozoic embayment; a progressive arc resulting from indentation of a point-shaped block situated either in Gondwana or in Avalonia, an oblique collision producing a non-cylindrical orogen, a thin-skinned origin produced by a progressive change in the transport direction of the thrust units similar to a photographic iris, a large scale trans-continental shear zone, and more recently a true orocline formed by the rotation around a vertical axis of an originally linear orogen. In this PhD thesis the kinematics and dynamics of the Ibero-Armorican orocline have been studied at a lithospheric scale through structural analysis, analogue modelling and detrital zircon geochronology. With the data presented in this thesis and all the previous data published, a plausible overall interpretation is that the Variscan orogen was folded around a vertical axis during the Pennsylvanian during a period that lasted about 10 m.y during the Late Pennsylvanian. The structures developed during the formation of Iberian-Armorican orocline buckling suggest that this process occurred due to a large change in the stress field from E-W to N-S (in present day coordinates), which implies that the folding of the orogen was produced by the mechanism of buckling. The buckling process affected the whole lithosphere, which would have been deformed by a dominant mechanism of longitudinal-tangential strain. According to the experimental analogue models, the root formed in the lithospheric-mantle beneath the core of oroclinal was probably caused by lithospheric folding. This root became gravitationally unstable at around the Carboniferous-Permian boundary. At that time it could begin to develop a Rayleigh-Taylor instability ending with the detachment and sinking of the lithosphericmantle in the asthenospheric-mantle. This process of lithospheric-mantle detachment would have produced an inversion of the topography as recorded by the detrital zircons

[es] El oroclinal Ibero Armoricano se sit?a en la cadena Varisca del suroeste de Europa, que es un or?geno a escala continental -con dimensiones de 8000 km de largo y 1000 de ancho- que se form? como consecuencia de una colisi?n continental producida durante el Dev?nico y el Carbon?fero. La deformaci?n Varisca representa la clausura de entre dos y cuatro oc?anos situados entre los continentes de Laurencia, B?ltica, Gondwana y varios microcontinentes durante la amalgamaci?n de Pangea. El oroclinal Ibero Armoricano se caracteriza por presentar un patr?n estructural con forma de arco de 180? que se puede seguir desde la pen?nsula de Breta?a, a trav?s del mar Cant?brico y el oeste de la pen?nsula Ib?rica, donde desaparece bajo el frente alpino del Sur de Iberia. Las interpretaciones m?s recientes consideran al oroclinal Ibero Armoricano parte de un sistema doble de oroclinales con forma de ?S? que contin?a hacia el sur de la pen?nsula en el arco Centroib?rico. El oroclinal Ibero Armoricano ha sido objeto de muchos estudios, especialmente en su n?cleo, que pretend?an resolver la cinem?tica de su curvatura. De estos estudios se han desprendido varias hip?tesis distintas para su formaci?n: un arco primario procedente de un golfo Neoproterozoico, un arco progresivo resultado de la indentaci?n de un bloque puntiagudo situado en Gondwana o Avalonia, una colisi?n no cil?ndrica, un origen epid?rmico basado en el cambio de la direcci?n de transporte de los mantos, una cizalla transcontinental y m?s recientemente un oroclinal verdadero formado por la rotaci?n de un or?geno linear alrededor de un eje vertical. En esta tesis se ha estudiado la cinem?tica y din?mica del oroclinal Ibero Armoricano a trav?s de la geolog?a estructural, la modelizaci?n an?loga y la geocronolog?a de circones detr?ticos. De los datos presentados en este trabajo y publicados anteriormente se puede interpretar que el or?geno Varisco fue plegado alrededor de un eje vertical durante el Pensilvaniense superior en un proceso de 10 millones de a?os de duraci?n. Las estructuras que se desarrollaron durante la formaci?n del mismo, sugieren que el proceso de plegamiento se produjo debido a un cambio en el r?gimen de esfuerzos de este-oeste a norte-sur (en coordenadas actuales) lo que implicar?a que el plegamiento se produjo por pandeo (buckling). Este proceso de plegamiento habr?a ocurrido a escala litosf?rica, que presumiblemente se deform? mediante el mecanismo de deformaci?n longitudinaltangencial. De acuerdo con la modelizaci?n an?loga este plegamiento producir?a una ra?z litosf?rica bajo el n?cleo del oroclinal producida posiblemente por plegamiento litosf?rico. Esta ra?z habr?a dejado de ser estable gravitacionalmente en el l?mite Carbon?fero-P?rmico, momento en el que comenzar?a una inestabilidad tipo Rayleigh-Taylor que acabar?a con el desprendimiento y hundimiento de la ra?z litosf?rica en el manto astenosf?rico. Un proceso dedesprendimiento litosf?rico como el descrito habr?a producido una inversi?n de la topograf?a como la que ha sido registrada en los circones detr?ticos