Lorenz Michel

Investigating feedbacks between tectonics and earth surface processes during rifting and continental breakup

Disentangling the interactions and possible feedbacks between tectonic and earth surface processes has been a focus of geoscientific research. Many previous studies were conducted in convergent settings and fewer studies focused on extensional settings. Here, we model the formation of continental extensional rift systems, using a geodynamic model coupled with a landscape evolution model.

We compare, how the structure of the subsequent rifts, topography and sedimentary yield evolve over time depending on the combination of five key parameters. This includes varying the crustal rheology, duration of extension, distribution of inherited strain, efficiency of erosion and the base level for erosion. The modeling results show that structure and topography of the intra-continental rifts strongly depend on crustal strength, on the distribution of inherited strain and on the duration of extension. High erosion rates are observed for models with significant topography and elevated rift shoulders. Hence, models that produce high topography (i.e. models with higher crustal strength) display a significant sediment flux during the syn-rift phase. In the post-rift phase, the sediment flux is often impacted by river capture events, which are more likely to occur for models with lower rift shoulders. Taken together, these observations suggest that there is a strong dependency of the sedimentary flux on the respective tectonic setting but also highlight the role played by earth surface processes, in particular in the post rift phase.