Interpreting and modelling late Quaternary dune accumulation in the southern Arabian Peninsula

• Relationship between dune chronological records and environmental forcing examined.
• OSL ages from the southern Arabian Peninsula are reviewed and evaluated.
• Numerical model can reproduce aeolian record.
• External forcing and local controls both important in influencing preserved record.

One of the fundamental questions in the reconstruction of Quaternary dryland environmental conditions is: what do dune OSL ages mean in terms of palaeoenvironmental change? This paper investigates the relationship between dune chronological records and external environmental forcing in the southern Arabian Peninsula during the last 30 ka. Aeolian records from the region are reviewed with reference to other regional palaeoenvironmental proxies, and these findings are related to a modelled assessment of dune response to the aeolian system state of the northeastern Rub' al Khali. The model replicates a range of features of the regional dune chronology when forced by three external parameters (sediment supply, sediment availability, and transport capacity), including extensive regional dune accumulation during the late Pleistocene–Holocene transition and reduced activity during the early Holocene humid period. Dune chronologies incorporate the influence of both external forcing parameters and localised short-term factors included as stochastic processes. Thick sedimentary units most likely represent external forcing conditions conducive to aeolian sediment transport and deposition, but at the same time these factors may be represented by periods of erosion of sediment at different sites. Confident interpretation of past environmental conditions is therefore not possible based on results from individual stratigraphic records. Sampling at multiple locations is needed in order to distinguish dune accumulation and preservation due to external forcing from stochastic processes of dune development.