- 1Department of Earth and Climate Sciences, Tufts University, Medford, MA, USA
- 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM, USA
- 3GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
- 4Institute of Geosciences, University of Potsdam, Potsdam, Germany
- 5Department of Geosciences, University of Fribourg, Fribourg, Switzerland
Rift-inversion orogens such as the High Atlas, Pyrenees, and Greater Caucasus exhibit strain localization primarily due to contractional reactivation of lithospheric weaknesses inherited from continental rifting, rather than from long-lived subduction leading to continental collision along a major plate boundary. These orogens thus experience a transition from extension to compression distinct from their plate-boundary counterparts that impacts georesource development and seismic hazard. It is widely recognized that the initial conditions prior to rift inversion strongly control the structural and thermal evolution of such orogens, yet it is difficult to derive initial conditions from available structural and thermochronologic data.
Here, we present geodynamic numerical modeling designed to capture the structural and thermal evolution of rift-inversion orogens. We complement our study with new Python routines to calculate synthetic low-temperature thermochronometric ages from the model results. This enables directly comparing our numerical results with thermochronometric data collected in natural rift-inversion orogens. Our initial results (Vasey et al., 2024) indicate three end-member structural styles in model orogens: 1) asymmetric underthrusting reminiscent of the Pyrenees and Greater Caucasus, 2) distributed thickening reminiscent of the High Atlas, and 3) polarity flip in which the vergence of the orogen varies over time. Synthetic apatite (U-Th)/He and fission track thermochronometric ages record regions of focused exhumation on the flanks of the initial rifts and in the hanging walls of major thrust faults in the final orogens, mirroring similar relationships between major structures and areas of greater exhumation observed in natural orogens.
These results demonstrate how geodynamic modeling can extend the ability of structural data and low-temperature thermochronology to help distinguish between competing models of pre-orogenic initial conditions.
Reference Cited:
Vasey, D.A., Naliboff, J.B., Cowgill, E., Brune, S., Glerum, A., and Zwaan, F., 2024, Impact of rift history on the structural style of intracontinental rift-inversion orogens. Geology, v. 52, no. 6, 429-434, doi:10.1130/G51489.1
How to cite: Vasey, D. A., Naliboff, J. B., Scully, P. M., Brune, S., Glerum, A., and Zwaan, F.: Modeling structural styles and thermochronometric ages in rift-inversion orogens to test pre-orogenic conditions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4863, https://doi.org/10.5194/egusphere-egu25-4863, 2025.
