Unravelling raked linear dunes to explain the coexistence of bedforms in complex dunefields.

ABSTRACT: Raked linear dunes keep a constant orientation for considerable distances with a marked asymmetry between a periodic pattern of semi-crescentic structures on one side and a continuous slope on the other. Here we show that this shape is associated with a steady-state dune type arising from the coexistence of two dune growth mechanisms. Primary ridges elongate in the direction of the resultant sand flux. Semi-crescentic structures result from the development of superimposed dunes growing perpendicularly to the maximum gross bedform-normal transport. In the particular case of raked linear dunes, these two mechanisms produces primary and secondary ridges with similar height but with different orientations, which are oblique to each other. The raked pattern develops preferentially on the leewar

SUBMITTER: Lu P 

PROVIDER: S-EPMC5290144 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature