Interplay of extension and erosion in metamorphic core-complex formation

• Applicant: Dr. Zoltán Erdos
• Subject Area: Geology ; Geophysics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569964069

Metamorphic core complexes (MCCs) are dome-shaped structures formed by low-angle extensional detachment faults, exhuming rocks from middle- to lower-crustal depths. Contemporary examples include the Shuswap complex in the North American Cordillera, the Cyclades MCCs and the Tauern window in the Eastern Alps. In general, MCCs often develop in active orogens or post-orogenic settings that are characterised by: (1) a complex, but regionally compressional stress field; (2) hot, thickened crust, with a high geothermal gradient; and (3) high topography. Even though MCCs have been studied extensively, the respective roles of the regional stress field and of the interactions between faulting and surface processes remain unexplored. This project aims at elucidating these outstanding questions by investigating the underlying mechanisms of core-complex formation through coupled 2D and 3D thermo-mechanical and surface-process models. The project consists of three work-packages. First, we will explore the effects of surface processes on MCC formation by conducting coupled surface-process, orographic precipitation and 2D finite-element thermo-mechanical numerical experiments. Second, we will investigate the role of the encompassing regional stress field in MCC formation using state-of-the-art 3D thermo-mechanical numerical experiments. Finally, we will assess the relative importance of surface processes, particularly erosion, and far-field forcing in the development of MCCs through a full 3D coupling of thermo-mechanical and surface-process models. Model predictions will be compared to observations from the Shuswap Complex, the Cyclades and the Tauern window to test the robustness and veracity of the results. These localities are ideally suited as natural laboratories because of their dense data coverage, including a wide range of thermochronological data, and their well-known evolution histories. We will use advanced age-prediction algorithms to generate synthetic thermochronology ages from PTt-paths extracted from our thermo-mechanical model experiments, and compare our findings to data available from our natural laboratories. Our results are expected to have broader implications for understanding continental core complexes globally, including examples like the Kongur Shan and Muztagata domes in the Pamir, as well as various core complexes in the North American Cordillera.

• DFG Programme: Research Grants
• International Connection: Austria, USA
• Co-Investigators: Professor Dr. Pieter van der Beek; Professor Dr. Sascha Brune
• Cooperation Partners: Professor Dr. Christoph von Hagke; Professorin Dr. Donna L. Whitney