sand wave Large-scale, transverse ridge of sand, characteristic of continental-shelf areas such as the southern North Sea. The external morphology is identical to that of the smaller-scale ripple-and-dune bedform (megaripple). The wavelength or spacing of sand-wave crests is 30–500 m and the height is 3–15 m. The down-current migration of sand waves leads to the formation of large-scale cross-bedding.

sand wave A large-scale, transverse ridge of sand that is characteristic of continental-shelf areas (e.g. the southern North Sea). The wavelength or spacing of sand-wave crests is 30–500 m and the height is 3–15 m. The down-current migration of sand waves leads to the formation of large-scale cross-bedding.