24/10/2024

Dr. Giridas Maiti

16:00 Uhr

Abstract: The horizontal propagation of slab detachment (slab tearing) is proposed to explain lateral migration of the mountain uplift and migration of foreland basin depocenters along many collisional belts. However, along‐strike differential collision due to an oblique passive margin geometry can have the similar effect. In this study, we employ 3D thermomechanical modeling to distinguish between the above-mentioned two processes. In our models, slab breakoff is triggered by the transition from oceanic to continental subduction, occurring earlier on one side of the passive margin than on the other due to the initial oblique configuration. However, once slab breakoff has begun, it spreads horizontally in the form of tearing at high velocity (∼38–118 cm/yr.), and associated topographic uplift also propagates with the same velocity. In contrast, the along‐strike migration of subsequent continental collision and related topographic uplift propagation is typically much slower (∼2–34 cm/yr). Similarly, the vertical magnitude of surface uplift caused by slab tearing is higher (up to 10 mm/yr) than the following collision phase (<4 mm/yr.). The parametric analysis reveals that slab tearing velocity and the associated horizontal propagation of mountain uplift depends on obliquity angle and slab age, whereas the migration of collision‐induced topographic growth is controlled by the convergence velocity and obliquity angle. Finally, our modeling results indicate that observations in nature, such as the relatively slow migration of basin depocenters and sedimentary facies changes, which are often interpreted as a consequence of slab tear propagation, might also be attributed to oblique continental collision.