The enigmatic curvature of Central Iberia and its puzzling kinematics

Abstract

<jats:p>Abstract. The collision between Gondwana and Laurussia that formed the latest supercontinent, Pangea, occurred during Devonian to early Permian times and resulted in a large-scale orogeny that today transects Europe, northwest Africa, and eastern North America. This orogen is characterized by an “S” shaped corrugated geometry in Iberia. The northern curve of the corrugation is the well-known and studied Cantabrian (or Ibero–Armorican) Orocline and is convex to the east and towards the hinterland. Largely ignored for decades, the geometry and kinematics of the southern curvature, known as the Central Iberian curve, are still ambiguous and hotly debated. Despite the paucity of data, the enigmatic Central Iberian curvature has inspired a variety of kinematic models that attempt to explain its formation but with little consensus. This paper presents the advances and milestones in our understanding of the geometry and kinematics of the Central Iberian curve from the last decade with particular attention to structural and paleomagnetic studies. When combined, the currently available datasets suggest that the Central Iberian curve did not undergo regional differential vertical-axis rotations during or after the latest stages of the Variscan orogeny and did not form as the consequence of a single process. Instead, its core is likely a primary curve (i.e., inherited from previous physiographic features of the Iberian crust), whereas the curvature in areas outside the core is dominated by folding interference from the Variscan orogeny or more recent Cenozoic (Alpine) tectonic events. </jats:p>

Evolution of the Alpine orogenic belts in the Western Mediterranean region as resolved by the kinematics of the Europe-Africa diffuse plate boundary

“…To the south, this displacement is suggested to be synchronous with the deformation of the Iberian orocline, in West and South Iberia block, along the North Pyrenean Shear Zone (Ballèvre et al, 2018) during the late Carboniferous-early Permian (Edel et al, 2018;Pastor-Galán et al, 2020). These results suggest that both Ebro and Sardinia-Corsica were tectonically distinct from Iberia.…”

Characterizing the Source of the Eastern Galicia Magnetic Anomaly (NW Spain): The Role of Extension in the Origin of Magnetization at the Central Iberian Arc

“…Extensional detachments probably exist in all these thermal domes, buried at depth as in the Sanabria Dome or hidden by the massive intrusion of late-orogenic, undeformed granites. If these anomalies, all located in the NW Iberian Massif, also imply the existence of a Kiaman remagnetization, the age of the closure of the CIA or even its existence, cannot be established by paleomagnetic techniques alone (Pastor-Galán et al, 2020), as magnetic remanence is probably syn-to-post arc.…”

Paleomagnetism from multi-orogenic terranes is "not a simple game": Pyrenees' Paleozoic warning

“…The trend of the Variscan belt in north Iberia follows a "C" shape known as the Cantabrian Orocline (e.g., Pastor-Galán et al, 2020). The Cantabrian Orocline seems isoclinal, formed by a northern and a southern E-W-trending limbs, but this is likely the product of a retightening during the Alpine orogeny (e.g., Pastor-Galán et al, 2011;Leite Mendes et al, 2021;Fig.…”

“…1) may be equivalent to the northern branch of the Cantabrian Orocline (e.g. García-Sansegundo et al, 2011;Pastor-Galán et al, 2020). Deformation, structural style and metamorphic grade show important differences along strike in the Pyrenees (Autran and García-Sansegundo, 1996;Debon and Guitard, 1996) and a N-S zonation, with fold-related cleavage being pervasive in the central and northern part of the Axial Zone but poorly developed in the south (García-Sansegundo et al, 2011).…”