Mechanisms for Knickpoint Generation in Response to Sea‐Level Change on Passive Margins

Knickpoints, or topographic perturbations within river profiles, are often attributed to uplift, climate or sea‐level change. However, knickpoint dynamics along continental shelves are poorly understood. Here, we use a landscape evolution model to simulate the response of an artificial passive margin to multiple sea‐level fluctuations in order to understand how knickpoints form and propagate inland. We demonstrate that, while it may be difficult for knickpoints to traverse an entire 100–200 km wide shelf within one lowstand, this is not necessary for preservation. The erodibility contrast between a soft coastal plain and a relatively resistant hinterland allows knickpoints to develop at the contact during eustatic lows. These knickpoints accumulate over multiple sea‐level cycles and generate a broad zone of rapid incision, which we relate to dated fluvial terrace incision along the US mid‐Atlantic margin.