Alma de Groot, The Netherlands
Dunes are wind-generated accumulations of sand particles present in desert or coastal land. Sand dunes have smooth and uniform forms, although geometry may be highly variable. The size of particles of sand dunes is highly concentrated around 0.2 mm in diameter due to wind transportation.
The pattern showed in the picture is the result of the formation of aeolian dunes on the beach, that subsequently were wetted by rain, and finally were eroded by wind again. Small pieces of shell debris and other organic material protect the sand locally. The pictured area is about 30 cm across.
This post was also published simultaneously in G-Soil.