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The gravel plain of the northern UAE is bounded to the east by the Musandam Mountains and to the west by the northernmost extension of the dunes of the Rub Al-Khali. Further west, beyond the dunes lies the coast of the Arabian gulf. The gravel plain comprises coalescent Quaternary alluvial fans, supplied with sediment from catchments in the Musandam Mountains. The boundary between the plain and the dunes follows the outline of the fans, and its width varies in relation to the size of the drainage basins supplying sediment to the fans. Linear dune ridges appear to wrap around the outline of the margins of the major fans. This suggests that the two landform assemblages are related. Where one wadi system crosses the dunefield the field relationships further suggest some contemporaniety of development. Where the mountain front is drained by catchments too small to sustain fan deposition, the dunes advance to the mountain front.

Correlations with other work suggest that there were major phases of both fan sedimentation and dune accumulation during the late Pleistocene. Cooler and/or wetter climatic conditions enhanced sediment supply to the alluvial fans. Strong northwesterly winds and greater sediment availability from the then dry floor of the Arabian Gulf may have been responsible for dune accumulation. Later dune reworking may reflect Holocene aridity. (C) 2003 Elsevier Ltd. All rights reserved.