Formation and reorganization timescales of aeolian landscapes

Abstract

Landscapes created through sediment transport are shaped by the interaction of flow and form. In landscapes where wind is the agent of geomorphic work, this is clear at the small-scale; equilibrium landform morphology is linked to the wind climate and the supply of sediment. At larger scales, this linkage becomes ambiguous because the form of giant dunes and dune fields integrate long histories of varied wind and sand supply. Without a framework to assess aeolian landscape evolution at this scale, the time taken to form and reorganize these landscapes has been largely unexplored quantitatively. We show that these timescales can be understood by linking modern wind and topographic datasets for one of the most expansive and morphologically diverse dune fields, the Rub’ al Khali. By linking sediment flux to the surface area and slope of the mobile landscape, and growth to the divergence in that flux, we fully couple form and flow at the aeolian landscape-scale. Our results show quantitatively how wind-blown landscape formation and reorganization is outpaced by climate change, the scale below-which the landscape can equilibrate with climate, and the implications for stratigraphic interpretation.