Displacement transfer from borders to interior of a plate: A crustal transect of Iberia

- N-S crustal transect across the Iberian Plate
- Extensional and contractional structure of the Basque-Cantabrian Zone
- Mid-crustal displacement transfer during intraplate deformation of Iberia
- Tectonic shortening in the upper and middle-lower crust in different ranges of Iberia
- The Alpine shortening of the Iberian Plate is estimated between 267 and 292 km

A N-S crustal transect of the whole Iberian Plate is presented. The displacement transfer during the Alpine deformation from the border ranges (Cantabrian and Betic chains) toward the interior ones was analyzed by means of balanced crustal sections. Inconsistencies in shortening values between upper and middle-lower crust in the Cantabrian Mountains (Basque-Cantabrian Zone) imply a mid-crustal detachment transferring orogenic shortening southward toward the Spanish Central System. Depending on the shortening value attributed to the Central System, this mid-crustal detachment could involve the entire Iberian Plate, connecting the Cantabrian Mountains and the Betic Chain. The very small crustal root in the Central System can be explained as a result of the tectonic load caused by the upper crustal shortening that was transferred from the border ranges. We conclude that a simple shear model, rather than a pure shear with lithospheric folding, better explains the whole Iberia deformation. Finally, the total Alpine shortening of the Iberian Plate is estimated between 267 and 292 km.