Not all basins are created equal: Lithospheric-scale analogue experiments of selective basin inversion

The inversion of rift basins is commonly associated with the reactivation of normal, basin-bounding faults or shear zones. Analogue models have shown how the reverse reactivation of these pre-existing structures facilitates the uplift of a basin’s sedimentary infill. However, few of these models examine the viscous processes occurring beneath the brittle crust, which may or may not drive basin inversion. In our study, we use lithospheric-scale analogue experiments of orthogonal extension followed by shortening to simulate rifting followed by inversion and orogenesis. Here we explore how the flow behaviours of ductile layers underneath rift basins promote or suppress basin inversion.

In our experiments, we simulate rifting by extending a multi-layer, brittle-ductile lithosphere which floats on a fluid asthenosphere, creating a system of distributed basins. This extension is followed by shortening of the model, during which strain is accommodated by the reactivation of basin-bounding faults and folding or upwelling of the ductile layers. These experiments reveal that the rheology of the ductile lower crust and lithospheric mantle, modulated by the imposed bulk strain rate, determine: (1) how rift basins are distributed during extension and (2) whether all or only some of these basins are inverted during shortening. We interpret that this selective basin inversion is related to the superposition of crustal-scale and lithospheric-scale boudinage during the basin-forming extensional phase. Our findings demonstrate that lithospheric-scale analogue models can be a powerful tool for investigating the interaction between brittle and viscous deformation during basin inversion.