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Coupling Surface Evolution and Mantle Dynamics

ASEG Webinar

Presenter: Claire Mallard

Title: Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics, Eustasy and Surface Processes

Abstract: Over deep time, mantle flow-induced dynamic topography as well as plate tectonic evolution drive deposition moderated by higher-frequency fluctuations in climate and sea level. The effects of deep mantle convection and lithospheric deformation impact all the segment of the source to sink systems at different wavelengths and over various scales which remains poorly quantified. Field observations and numerical investigations suggest that the long-term stratigraphic record along continental margins contains essential clues on the interactions between dynamic topography and surface processes. However, it remains challenging to isolate the fingerprints of dynamic topography, lithospheric deformation, eustatic variation and climate change in the geological record. In the first part of the talk, I will show you how we use a new numerical simulation package that couples the open-source surface evolution code Badlands (https://badlands.readthedocs.io/en/la...) with lithospheric-scale thermo-mechanical models (https://uwgeodynamics.readthedocs.io/...) for unravelling the effect of rift obliquity on the distribution of facies and the evolution of stratigraphic architecture in syn-rift deposits. The second part will focus on the integration of mantle convection simulation results into Badlands to quantify the impact of different timings and wavelengths of dynamic topography migration on the surface. I will present an example of the last 40 Ma evolution of the South African landscape. The results suggest that our source-to-sink numerical workflow can be used to explore, in a systematic way, the interplay between dynamic topography and surface processes and can provide insights into recognizing the geomorphic and stratigraphic signals of dynamic topography in the geological record.