Definition of ripple mark

i. An undulatory surface or surface sculpture consisting of alternating subparallel small-scale ridges and hollows formed at the interface between a fluid and incoherent sedimentary material (esp. loose sand). It is produced on land by wind action and subaqueously by currents or by the agitation of water in wave action, and generally trends at right angles or obliquely to the direction of flow of the moving fluid. It is no longer regarded as evidence solely of shallow water.



Ref: AGI

ii. One of the small and fairly regular ridges, of various shapes and cross sections, produced on a ripple-marked surface; esp. a ripple preserved in consolidated rock and useful in determining the environment of deposition. The term was formerly restricted to symmetrical ripple mark, but now includes asymmetrical ripple mark. The singular form may be used to denote general ripple structure (as well as a specific ripple), and the plural form to describe a particular example.