The importance of inherited lithospheric architecture on foreland basin architecture: inferences from the Molasse Basin

The architecture of a foreland basin records the adjacent mountain range's tectonic evolution and climatic history. The Northern Alpine Foreland Basin, also known as the Molasse Basin, has a non-cylindrical architecture, hinting at along-strike variations in Alpine tectonics and climate history. Previous studies suggest that slab tearing, a process by which slab breakoff propagates along-strike, is the primary driver of the foreland basin’s non-cylindrical evolution. However, a quantitative assessment of the slab tearing on the evolution of Molasse Basin architecture is lacking. Moreover, the heterogeneity present in the European passive margin architecture can add further complexity to the slab tear evolution and associated foreland basin evolution. Here, we integrate geodynamic and stratigraphic (depositional) forward models to evaluate the effect of potential drivers and compare them to Molasse Basin architecture. In the geodynamic models, we vary along-strike passive margin age, initial obliquity of the passive margin with respect to the upper plate, and presence of microcontinent. We quantify the effects of these processes on the slab tear evolution, subsequent continental collision and resulting along‐strike variable foreland basin development. Our results highlight that the subduction of the irregular European passive margin caused a cascade of regional tectonic events leading to the heterogeneous architecture of the Molasse Basin. More specifically, the lateral propagation of slab tearing was the dynamic response to the collision of the irregular passive continental margin. The resultant along-strike variations in slab pull controlled the contrasting evolution of depositional environments in the Molasse Basin along the strike.