Robert Moucha, Syracuse University

Continental rifting is an integral process of plate tectonics and a key stage in the tectonic Wilson cycle that can lead to the breakup of continents and generation of new oceanic crust. The evolution of continental rifts involves a combination of tectonic, magmatic, and surface processes. Understanding the intricate interplay between these processes is essential for unraveling their complex history that is recorded in the sedimentary rift basins.  Climate driven processes: weathering, erosion, sediment transport, and deposition, have been shown to impact the stress state and deformation in extensional settings. However, a number of these models have utilized a simplified approach to modeling surface processes (e.g., Olive et al., 2014) and only a few have coupled geodynamic models with sophisticated models of landscape evolution that can separate marine and terrestrial surface processes (e.g. Theunissen & Huismans, 2019; Neuhart et al., 2022). In this presentation I will give an overview of one such coupling approach and present results of our geodynamic-landscape evolution coupling with a focus on the sedimentary system and the influence of paleotopography and different sizes of pre-existing structural weakness. 

To study the behavior of continental rifting we use ThermoMech 2D, a thermomechanical numerical code based on the primitive variable particle-in-cell finite-difference method developed by Taras Gerya and others (Gerya, 2010; & references therein). The advantage of this numerical approach is that specific material properties are inherently traced through time negating the need for numerous high-resolution grids. We track both age and water depth of sediment deposition as well as temperature and pressure. In addition to material properties, surfaces such as topography, basement, and stratigraphical horizons, are also be tracked.  Surface processes are simulated using an open-source landscape evolution code called Fastscape (fastscape.org; Braun & Willett, 2013; Yuan et al., 2019a, 2019b). Fastscape adopts a stream-power law fluvial bedrock erosion with both hillslope and marine diffusion to generate, transport and deposit sediment in marine or lacustrine environments. 

References 

Gerya, T.V., 2010. Introduction to Numerical Geodynamic Modelling. Cambridge University Press, New York. 

Braun, J., & Willett, S. D. (2013). A very efficient O(n), implicit and parallel method to solve the stream power equation governing fluvial incision and landscape evolution. Geomorphology, 180–181, 170–179. https://doi.org/10.1016/j.geomorph.2012.10.008 

Neuharth, D., Brune, S., Wrona, T., Glerum, A., Braun, J., & Yuan, X. (2022). Evolution of Rift Systems and Their Fault Networks in Response to Surface Processes. Tectonics, 41(3). https://doi.org/10.1029/2021TC007166 

Olive, J.A., Behn, M. D., & Malatesta, L. C. (2014). Modes of extensional faulting controlled by surface processes: Normal faulting and surface processes. Geophysical Research Letters, 41(19), 6725–6733. https://doi.org/10.1002/2014GL061507 

Theunissen, T., & Huismans, R. S. (2019). Long‐Term Coupling and Feedback Between Tectonics and Surface Processes During Non‐Volcanic Rifted Margin Formation. Journal of Geophysical Research: Solid Earth, 124(11), 12323–12347. https://doi.org/10.1029/2018JB017235 

Yuan, X. P., Braun, J., Guerit, L., Rouby, D., & Cordonnier, G. (2019a). A New Efficient Method to Solve the Stream Power Law Model Taking Into Account Sediment Deposition. Journal of Geophysical Research: Earth Surface, 124(6), 1346–1365. https://doi.org/10.1029/2018JF004867 

Yuan, X. P., Braun, J., Guerit, L., Simon, B., Bovy, B., Rouby, D., Robin, C., & Jiao, R. (2019b). Linking continental erosion to marine sediment transport and deposition: A new implicit and O(N) method for inverse analysis. Earth and Planetary Science Letters, 524, 115728. 

1. webinar
2. 2024