How Rift-related/Plate-forming Processes Control Structure and Shortening in Fold-thrust Belts

Abstract

Fold-thrust belts (FTBs) are archetypical tectonic features adjacent to collisional orogens, where structural traps account for 14% of discovered oil reserves. After decades of field and seismic surveys, detailed geological interpretations have emphasized their high degree of structural complexities. This has dampened academic research interest and impetus towards the understanding of larger scale geodynamic processes related to their development. FTBs express processes by which plate convergence in collisional orogenic belts is accommodated by accretion within the continental lithosphere. Two dominant tectonic modes are observed in FTBs, thin-skinned and thick-skinned. Thin-skinned style characterized regions dominated by underthrusting, suggesting simple-shear subduction of the underlying crust. A recently discovered relationship between structure of FTBs and plate forming processes (Mouthereau et al., 2013) shows that styles of tectonic deformation at the front of orogenic belts are controlled by age-dependent, deep-seated, properties of the crust and sub-continental mantle. More generally, the role of inherited thermo-tectonic properties of the lithosphere and the architecture of former continental margins is increasingly being shown to be a major driver in the evolution of mountain belts. This research should stimulate novel R&D integrated efforts on both rifted margin and thrust belt.