Evaluating balanced section restoration with thermochronology data: A case study from the Central Pyrenees

Abstract

We present a new method that can be used to quantitatively evaluate the consistency between balanced section restorations and thermochronological data sets from orogenic belts. We have applied our method to a crustal-scale area-balanced cross-section restoration along a profile in the Central Pyrenees. This restoration is well constrained and supported by a wide variety of geological and geophysical data. Moreover, an extensive thermochronological data set has been collected independently in the area. We use the structural-kinematic software 2D-Move ™ to constrain a set of velocity fields that describes the kinematics of the Central Pyrenees. Using these velocity fields as input for the thermokinematic code PECUBE, we derive predictions of the thermal history and a range of thermochronometric ages for the modeled area. We find that the kinematic history of the belt as inferred from section balancing is in good agreement with the published thermochronological data. High-temperature (zircon fission-track and K-feldspar Ar-Ar) data constrain the thermal structure of the belt as well as the timing of underplating. Low-temperature (apatite fission-track and (U-Th)/He) data require late synorogenic sedimentary burial of the southern flank of the Pyrenees between late Eocene (40 Ma) to late Miocene (9 Ma) times, consistent with previous studies, and imply that no such burial occurred on the northern flank.

Placing limits to shortening evolution in the Pyrenees: Role of margin architecture and implications for the Iberia/Europe convergence

“…Because most thrust units were already emplaced at 35 Ma, an increased of incoming fluxes may have two different origins. If Model A is preferred, this could be related to the indentation of the subducting Iberian basement below the Axial Zone, thus reactivating deformation in the Orri unit [ Beaumont et al ., ; Erdős et al ., ]. Otherwise, as suggested by Huyghe et al .…”

Sediment provenance and routing evolution in the Late Cretaceous–Eocene Ager Basin, south‐central Pyrenees, Spain

“…However, characterization of the ZHe signatures from potential source regions is imperative for utilizing the ZHe signal as a provenance tracer. Low‐temperature thermochronometric constrains on potential source regions in the Pyrenees, north of the Ager Basin, reveal bedrock zircon and apatite fission‐track and (U‐Th)/He cooling ages that are commonly <90 Ma (Beamud et al, ; Bosch et al, ; Erdos, Beek, & Huismans, ; Fitzgerald et al, ; Labaume, Meresse, Jolivet, & Teixell, ; Metcalf et al, ; Morris et al, ; Mouthereau et al, ; Sinclair et al, ; Vergés et al, ). Overall these cooling ages display a systematic spatial trend with ages younging towards the southwest, suggesting a north to south and east to west propagation of exhumation in response to the oblique convergence between Iberia and Eurasia.…”

Detrital zircon (U‐Th)/(He‐Pb) double‐dating constraints on provenance and foreland basin evolution of the Ainsa Basin, south‐central Pyrenees, Spain

“…Thermochronometric studies of the Axial Zone basement rocks reveal a multiphase tectonic and exhumation history from 70 to 20 Ma [ Morris et al , ; Fitzgerald et al , ; Sinclair et al , ; Metcalf et al , ; Beamud et al , ; Rahl et al , ; Rushlow et al , ; Erdos et al , ; Labaume et al , ]. Bedrock zircon fission track, zircon (U‐Th)/He, apatite fission track, and apatite (U‐Th)/He studies show several clear spatial trends in cooling ages of all thermochronometers.…”

“…DZ (U‐Th)/(He‐Pb) double dating represents a potent way of reducing provenance ambiguities and possibly discriminating between these competing models. The laterally continuous exposure, biostratigraphic/magnetostratigraphic depositional constraints [ Puigdefàbregas and Souquet , ; Bentham and Burbank , ; Mochales et al , ; Scotchman et al , ; Mochales et al , ], and well‐constrained structural evolution of the Ainsa Basin [ Teixell , ; Fitzgerald et al , ; Sinclair et al , ; Metcalf et al , ; Erdos et al , ; Teixell et al , ] provide a unique setting to apply DZ (U‐Th)/(He‐Pb) methodology in high resolution. Furthermore, the crystallization and cooling age constraints of the crystalline basement exposed in the Axial Zone allow for a detailed sedimentary provenance analysis and reconstruction of sediment source regions throughout early orogenesis [ Solé et al , ; Denèle et al , ; Hart et al , ; Martínez et al , ] (Figure ).…”