2019 journal article
Evolving paleotopography and lithospheric flexure of the Pyrenean Orogen from 3D flexural modeling and basin analysis
Earth and Planetary Science Letters, 515, 26–37.
manuscript.elsevier.com (publisher PDF)
Source: ORCID
Added: March 1, 2024
We present the results of a numerical modeling study of the Pyrenees Mountains investigating the spatio-temporal variation in lithospheric flexure in response to the developing orogen, with the aim of setting constraints on paleotopography. We employ a finite-element method to model the 3D flexural deformation of the lithosphere beneath the Pyrenean orogen since the onset of convergence in the Late Cretaceous. Using subsurface and structural data, we describe the evolving geometry of both the northern Aquitaine and southern Ebro foreland basins at the Paleocene (early orogenic phase), the end- and mid-Eocene (peak orogenic phase), the Oligocene (late orogenic phase), and the present (post-orogenic phase). The flexural modeling provides insight into how both the rigidity of the lithosphere and the paleotopographic load have varied over the course of orogenesis to shape the basin geometry. Employing a 3D continuous-plate model, we find that the overriding European plate has slightly higher rigidity than the underthrusting Iberian plate. The best-fit model results for the modern setting produce a root-mean-square error (RMSE) of 458 m using effective elastic thickness (Te) values of 23 and 16 km for the European and Iberian plates, respectively. We also test a broken-plate model, which produces a similar RMSE but predicts higher Te (32 km for the European plate and 26 km for the Iberian plate). The broken-plate model results indicate minimal vertical plate-boundary forces are necessary to reproduce the observed basin geometry. Flexural modeling results suggest that the topographic load doubled from the Paleocene to the Oligocene, and achieved modern topography by the end of the Eocene. The topography remained relatively stable throughout the Oligocene and Neogene, with only limited growth and decay. These results have implications for surface processes and foreland-basin development of the Pyrenean Orogen, tectonic inheritance, and the geodynamic evolution of Western Europe.