Aeolian and fluvial sediment transport are important mechanisms in shaping the Earth surface. Both are driven by regional and local environmental conditions, which include interactions between these two geomorphic processes. Along the 400-km segment of the Colorado River that flows through Grand Canyon National Park, USA we find aeolian dunes sourced by fluvial sediment. Many of these dunes are inactive, characterized by vegetated or biological soil crust-covered immobile sediment, though some are active dunes, characterized by bare mobile sediment. In this talk, we explore why active and inactive dunes coexist in this fluvial-aeolian environment and consider if changes in sediment connectivity might drive state transitions. We apply novel aeolian morphodynamics research using geomorphic change detection to evaluate the role of climate, river regulation, and sediment supply on decades of aeolian activity.
Date and Time: Jan 27th, 2026 at 8:00:00 am MST (AZ, USA)