Evolution of the High-Elevation Eastern Red Sea Rifted Margin: Morphology, Uplift Processes, and Source-to-Sink Dynamics

This presentation explores the formation and evolution of high-elevation passive margins, focusing on the eastern Red Sea region and the relationship to the Red Sea stratigraphy. We address gaps in our understanding of the origin and evolution of erosional escarpments along rifted margins. We combine geological observations, geomorphic mapping, and paleo-topography to calculate erosion rates and compare them to sedimentation rates. We present a landform map and landscape evolution model of the Eastern Red Sea Rifted Margin (ERSRM). It highlights different erosion phases and their timing for two separate domains: on the Arabian plateau, an old planation surface that was rifted, uplifted and exhumed since the Oligocene, and a young (<15 Ma) foothills belt which formed by the eastward retreat of the Arabian Escarpment. These observations allow estimates of post-rift erosion volumes and rates. At the end of rifting ~14 Ma ago, erosion rates are high and remain relatively high (although decreasing) up to 5 Ma. Then a dramatic drop in erosion rates occurs and we discuss whether this is due to margin equilibrium or climate changes. While eroded and sedimented volumes are in the same range, an overall deficit in eroded volumes is observed. Furthermore, we identified three different settings controlling escarpment evolution along the margin. We discuss the relationship between the morphology of the escarpment and the segmented structure of the ERSRM. By bridging the gap between onshore geomorphic evolution and coastal basin stratigraphy, this study contributes to a comprehensive understanding of the long-term evolution of rifted margins.