Presenter
Xuesong Ding, Ph.D.
Research Assistant Professor
Bureau of Economic Geology
Jackson School of Geosciences
The University of Texas at Austin
Description
Sequence stratigraphic models are used to predict basin-margin facies changes, which have been related to sea level. However, those models do not always account for the role of sediment supply in controlling stratigraphy. Moreover, they can underrepresent the interactions between surface processes and external forcings. We use coupled landscape evolution-stratigraphic models to evaluate the evolution of nearshore deposition as a result of tilting. We create a generic sediment-routing system with sediment transport governed by hillslope diffusion and channel incision, and impose tilting along a hinge axis at the model center. We show that on the subsided side of the model relative sea level rises and rivers are captured. As a result, the subsided side receives more sediment supply compared to the uplifted side, and the stratigraphy shows a transition from more retrogradation to progradation depending on whether subsidence is high or low, respectively. On the uplifted side, rivers are diverted away, the stratigraphy shows degradation unless uplift is slow enough to allow progradation. An additional surprising result of our experiments is that, regardless of tilting magnitude, the uplifted side of the model showed only very local erosion along river pathways; the majority of uplifted surface area is a non-erosive depositional hiatus. Therefore, such surfaces predominantly representing stasis could be indicative of tectonic uplift events.
