Spatio-temporal patterns of Pyrenean exhumation revealed by inverse thermo-kinematic modeling of a large thermochronologic data set

ally, a recently published model of orogen-scale topographic evolution (Curry et al., 2019) constrains surface uplift through time, providing a rare opportunity to investigate spatio-temporal variations in both exhumation and rock uplift. Pyrenean exhumation is variably attributed to (1) southward-propagating deformation of an orogenic wedge (Fitzgerald et al., 1999; Sinclair et al., 2005), (2) westward-propagating defor Large thermochronologic data sets enable orogen-scale investigations into spatio-temporal patterns of erosion and deformation. We present the results of a thermo-kinematic modeling study that examines large-scale controls on spatio-temporal variations in exhumation as recorded by multiple low-temperature thermochronometers in the Pyrenees mountains (France/Spain). Using 264 compiled cooling ages spanning similar to 200 km of the orogen, a recent model for its topographic evolution, and the thermo-kinematic modeling code Pecube, we evaluated two models for Axial Zone (AZ) exhumation: (1) thrust sheet-controlled (northsouth) exhumation, and (2) along-strike (east-west) variable exhumation. We also measured the degree to which spatially variable post-orogenic erosion influenced the cooling ages. We found the best fit for a model of along-strike variable exhumation. In the eastern AZ, rock uplift rates peak at >= 1 mm/yr between 40 and 30 Ma, whereas in the western AZ, they peak between 30 and 20 Ma. The amount of post-orogenic (<20 Ma) erosion increases from <1.0 km in the eastern Pyrenees to >2.5 km in the west. The data reveal a pattern of exhumation that is primarily controlled by structural inheritance, with ancillary patterns reflecting growth and erosion of the antiformal stack and post-orogenic surface processes.

Automated summary

By studying large-scale thermokinematic modeling of the Pyrenees mountains, it was found that the pattern of exhumation is primarily controlled by structural inheritance, with ancillary patterns reflecting growth and erosion of the antiformal stack as well as post-orogenic surface processes.