“The Wave” located in Arizona near the Utah border in the USA is a colourful rock formation made of sandstone. Initially formed in the Jurassic period by migrating sand dunes the sandstone has since been eroded into this spectacular shape.
Eroded firstly through rainwater runoff sourced from a drainage basin nearby. The rainwater followed the path of least resistance along weak points such as joints and fractures creating the U-shaped troughs as the sediment washed away.
Secondly after the shrinkage of the drainage basin wind became the predominant force of erosion. Over time this created the wave features as the wind was naturally funneled through the troughs. The orientation of the erosional steps and risers show the superior wind direction over the millions of years of erosion. The ribbing that is visible is due to slightly different types of sandstones making up the formation, some more compacted and/or harder than others thus harder to erode so stick out over the weaker types.
Interestingly there have been trace fossils of various types of Jurassic dinosaurs and other desert dwelling creatures of the time found in the formation.
For more information and stunning photos (including the one here):