DECONSTRUCTING A SAND SEA: AN EXAMPLE FROM THE NORTHERN RUB’ AL-KHALI IN THE UAE

The northern Rub’ Al-Khali sand sea in the United Arab Emirate exhibits a complex pattern of dunes, comprising large compound crescentic dunes in the south and W-E trending linear dunes in the north and east, in addition to areas of crescentic dunes and sand sheets on the northwestern margins of the sand sea. The linear dunes are modified in many places by superimposed crescentic dunes and star dune peaks. The areas of different dunes are hypothesized to represent temporally distinct generations of aeolian accumulation and/or reworking.

Analyses of digital elevation models and satellite images provide new insights into the geomorphic relationships between dune pattern elements and to older partially lithified aeolian units, while synthesis of available luminescence ages provides evidence for multiple periods of aeolian accumulation and stability. The complex pattern of dune pattern elements reflects a long history of sand accumulation and reworking involving both quartz-rich and carbonate-rich sands, as well as modification of pre-existing dunes in response to climatic and sea level changes that affected sediment supply, availability, and mobility. It is however challenging to relate the majority of dune pattern elements to specific episodes of aeolian activity, indicating that carefully targeted programs of luminescence dating are needed for understanding of sand sea and dune evolution and response to climate and sea level changes.