• Robert Sullivan
Living reference work entry


A relatively large aeolian ripple with a bimodal grain size frequency, the coarser component of which is commonly (but not necessarily) 1–2 mm diameter.


Aeolian ridge (Bagnold 1941); Coarse-grained ripple (Jerolmack et al. 2006); Granule ripple (Sharp 1963). The term “granule ripple” is common but can be misleading if the coarse surface grains are not actually granule-sized. The term “megaripple” (e.g., Greeley and Iversen 1985, p. 154) does not imply a factor of 106. The term “coarse-grained ripple” (Jerolmack et al. 2006) avoids these problems but is not widely used.


Megaripples differ from common aeolian impact ripples by having bimodal texture and generally larger sizes (heights up to several decimeters). Coarse sand (500–1,000 μm), very coarse sand (1–2 mm), or granules (2–4 mm) dominate surfaces, particularly at crests, but significantly finer grains dominate megaripple interiors (Fig. 1). Sinuosity of crests is common. Megaripples occur singly,...


Sand Dune Coarse Sand Coarse Fraction Negev Desert Mars Exploration Rover 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Center for Radiophysics and Space ResearchCornell UniversityIthacaUSA