Morphological and sedimentary characteristics of dome dunes in the northeastern Qaidam Basin, China

Abstract

Oval dome dunes, which lack a slipface, represent a specific phase of barchan dune evolution that has undergone distinctive morphodynamic processes. In the northeastern Qaidam Basin, China, we measured the morphological parameters of 60 dome dunes by means of real-time kinematic GPS. The dome dunes had an oval plan view and an asymmetrical side view, with mean lengths of 14.49 and 13.26m for the long and short axes, respectively, with mean windward and leeward slopes of 4.56 and 5.07°, respectively. Dune heights ranged between 0.12 and 0.91m, and averaged 0.52m. By examining the characteristics of the dune sediments, the internal sedimentary structures, and regional wind regimes, we found that local alluvial and fluvial sediments appear to provide the necessary materials for the dome dunes, and that the dunes evolved from sand patches under a variable, gentle winter wind. According to our results and the Andreotti saturation length theory, we estimated the lengths at which the dome dunes disperse or begin to evolve into barchan dunes. This knowledge will enhance our understanding of dome dune morphodynamic processes and improve numerical simulations of dune evolution.