Armin DIELFORDER
Supervisor:
Mary Ford, CRPG Nancy
Major Results
Late Cretaceous Iberia-Europe convergence caused the formation of a convergent plate boundary fault between the continents. The rheological strength of the fault governed plate coupling and the transmission of compressive stress into Europe. Initially strong plate coupling drove deformation in Europe, which ceased after ~15–20 Myr due to a weakening of the plate boundary fault.
Abstract
Based on mechanical considerations, numerical simulations, and geological reconstructions, we examine how the dynamics of intraplate deformation were governed by the formation of a convergent plate boundary fault between Iberia and Europe. During the Late Cretaceous, plate convergence was accommodated by the inversion of a young hyperextended rift system separating Iberia from Europe. Our analysis shows that the strength of the lithosphere beneath this rift was initially sufficient to transmit large compressive stresses far into Europe, though the lithosphere beneath the rift was thinned and thermally weakened. Continued convergence forced the formation of the plate boundary fault between Iberia and Europe.
The fault evolved progressively and constituted a lithosphericscale structure at the southern margin of Europe that weakened rheologically. This development caused a decrease in mechanical coupling between Iberia and Europe and a reduction of compressional far field stresses, which eventually terminated intraplate deformation in Central Europe. Taken together, our findings suggest that the Late Cretaceous intraplate deformation event records a high force transient that relates to the earliest strength evolution of a lithospheric-scale plate boundary fault.
Setup and key variables of the numerical simulations of hyperextension followed by convergence and inversion, showing in particular the initiation of the plate boundary fault. (a) Model setup. LAB = lithosphere-asthenosphere boundary. (b) Post-rift/pre-convergence margin structure. (c-e) Fault kinematics. (f-h) Strain rate. (i-k) Friction coefficient. (l-n) Geotherms derived from the numerical simulations.
Formation of the Iberian‐European Convergent Plate Boundary Fault and Its Effect on Intraplate Deformation in Central Europe
Formation of the Iberian‐European Convergent Plate Boundary Fault and Its Effect on Intraplate Deformation in Central Europe
Dielforder, A., Frasca, G., Brune, S. & Ford, M. (2019): Formation of the Iberian- European Convergent Plate Boundary Fault and Its Effect on Intraplate Deformation in Central Europe. AGU.
keywords: intraplate deformation, orogeny, plate boundary fault, plate coupling force, Pyrenees, lithosphere dynamics