303-2 Landscape–Tectonic Interactions in Continental Rifts: A Modeling Perspective from the East African Rift System

Session: Honoring the Late Professor Mohamed Abdelsalam: Outstanding Researcher, Generous Colleague, Legendary Mentor, and Ambassador for the Geosciences In Africa (Posters)

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The evolution of continental rifts significantly reshapes landscapes by uplifting rift shoulders and subsiding rift basins, driving localized erosion and deposition. The development of rift border and intrarift faults considerably alters the drainage system and river incision in rift regions. These surface processes, in turn, can influence tectonic deformation patterns. However, the sensitivity of faulting to climate-driven landscape evolution remains poorly understood, particularly in oblique rift settings like those in East Africa. In this study, we use 3D numerical models that couple tectonics with surface processes to investigate how climate variability affects long-term fault evolution in oblique rifts. Our results show that erosion and sedimentation modify gravitational potential energy and deviatoric stress, thereby altering patterns of strain localization. Under high rates of erosion and sedimentation, deformation localizes early along border faults, leading to a progressive transition from full-graben to half-graben geometries. In contrast, under limited surface processes, long-lived en-echelon fault networks dominate, and strain migrates away from the initial weak zone. These contrasting faulting styles reshape the locus and orientation of crustal thinning, with implications for magmatism, rift segmentation, and continental breakup. Our findings highlight the critical role of climate-driven landscape evolution in controlling tectonic architecture and offer new insights into the coupled development of surface and tectonic processes in the East African Rift System.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6108

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